NITROGEN-CONTAINING AROMATIC OR RING STRUCTURE MOLECULES FOR PLASMA ETCH AND DEPOSITION
20240242971 ยท 2024-07-18
Inventors
Cpc classification
H01L21/32056
ELECTRICITY
International classification
H01L21/311
ELECTRICITY
H01L21/3205
ELECTRICITY
Abstract
A method for forming a substantially vertical structure comprises: exposing a substrate to a vapor of an additive comprising a nitrogen-containing cyclic compound, the substrate having a film disposed thereon and a patterned mask layer disposed on the film, activating a plasma to produce an activated nitrogen-containing cyclic compound, and allowing an etching reaction to proceed between the film uncovered by the patterned mask layer and the activated nitrogen-containing cyclic compound to selectively etch the film from the patterned mask layer, thereby forming the substantially vertical structure, wherein the nitrogen-containing cyclic compound reduces a charge that builds up along sidewalls of the substantially vertical structure forming a conductive sidewall passivation layer on the sidewalls thereof. A method of depositing a conductive polymer layer on a substrate and a cyclic method are also disclosed.
Claims
1. A method for forming a substantially vertical structure, the method comprising: exposing a substrate to a vapor of an additive comprising a nitrogen-containing cyclic compound, the substrate having a film disposed thereon and a patterned mask layer disposed on the film; activating a plasma to produce an activated nitrogen-containing cyclic compound; and allowing an etching reaction to proceed between the film uncovered by the patterned mask layer and the activated nitrogen-containing cyclic compound to selectively etch the film from the patterned mask layer, thereby forming the substantially vertical structure, wherein the nitrogen-containing cyclic compound reduces a charge that builds up along sidewalls of the substantially vertical structure forming a conductive sidewall passivation layer on the sidewalls thereof.
2. The method of claim 1, further comprising prior to activating the plasma, sequentially or simultaneously exposing the substrate to one or more hydrofluorocarbon or fluorocarbon etching gases with the additive, wherein the one or more hydrofluorocarbon or fluorocarbon etching gases are selected from C.sub.4F.sub.6, C.sub.4F.sub.8, C.sub.4H.sub.2F.sub.6, CHF.sub.3, CH.sub.2F.sub.2, CH.sub.3F, CF.sub.4, C.sub.2F.sub.6, C.sub.3F.sub.8, SF.sub.6, NF.sub.3, C.sub.2F.sub.4, C.sub.3F.sub.6, C.sub.4F.sub.10, C.sub.5F.sub.8, C.sub.6F.sub.6, C.sub.1-C.sub.6 C.sub.xF.sub.y molecule (x and y are integers), C.sub.2H.sub.5F, C.sub.3H.sub.7F, C.sub.3H.sub.2F.sub.6, C.sub.2HF.sub.5, or combination thereof, or HBr, HCl, HI, HF, or H.sub.2.
3. The method of claim 1, further comprising prior to activating the plasma, sequentially or simultaneously exposing the substrate to an inert gas with the additive, wherein the inert gas is selected from Ar, Kr, Xe, Ne, N.sub.2, He or combination thereof.
4. The method of claim 1, further comprising prior to activating the plasma, sequentially or simultaneously exposing the substrate to a co-reactant with the additive, wherein the co-reactant is selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS or combinations thereof.
5. The method of claim 1, wherein the nitrogen-containing cyclic compound contains a cyclic or aromatic structure, at least 1 double C?C bond and at least one nitrogen contained within the cyclic or aromatic structure.
6. The method of claim 1, wherein the nitrogen-containing cyclic compound has a general formula C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3; X=F, Cl, Br or I (halogens), X=F, Cl, Br, I (halogens) or CN group, where X?X, provided that the nitrogen-containing cyclic compound excludes C.sub.5F.sub.5N (CAS No.: 700-16-3), C.sub.3F.sub.4N.sub.2 (CAS No.: 478693-81-1), C.sub.4N.sub.2F.sub.4 (CAS No.: 13177-77-0), C.sub.4N.sub.2F.sub.4 (CAS No.: 767-79-3), C.sub.3F.sub.3N.sub.3 (CAS No.: 675-14-9), C.sub.4NF.sub.5 (CAS No.: 445235-48-3), C.sub.3F.sub.4N.sub.2 (CAS No.: 478693-82-2), C.sub.4N.sub.2F.sub.4 (CAS No.: 7627-80-7), C.sub.3F.sub.2N.sub.3Cl (CAS No.: 696-85-5), C.sub.3FN.sub.3Cl.sub.2 (CAS No.: 696-84-4), and C.sub.3N.sub.3Cl.sub.3 (CAS No.: 108-77-0).
7. The method of claim 1, wherein the nitrogen-containing cyclic compound is selected from C.sub.5HF.sub.4N (CAS No.: 2875-18-5), C.sub.5F.sub.5N (CAS No.: 700-16-3), C.sub.3F.sub.3N.sub.3 (CAS No.: 675-14-9), C.sub.3F.sub.3N.sub.3 (CAS No.: 112291-51-7), C.sub.3F.sub.3N.sub.3 (CAS No.: 75995-67-4), C.sub.4F.sub.4N.sub.2 (CAS No.: 13177-77-0), C.sub.4F.sub.4N.sub.2 (CAS No.: 7627-80-7), C.sub.4F.sub.4N.sub.2 (CAS No.: 767-79-3), C.sub.6F.sub.9N.sub.3 (CAS No.: 368-66-1), C.sub.5H.sub.2F.sub.3N (CAS No.: 3512-18-3), C.sub.5H.sub.2F.sub.3N (CAS No.: 67815-54-7), C.sub.5H.sub.2F.sub.3N (CAS No.: 76469-41-5), C.sub.5H.sub.2F.sub.3N (CAS No.: 837365-04-5), C.sub.3HF.sub.2N.sub.3 (CAS No.: 1207861-13-9), C.sub.3HF.sub.2N.sub.3 (CAS No.: 919785-60-7), C.sub.3H.sub.2FN.sub.3 (CAS No.: 96100-45-7), C.sub.5F.sub.7N.sub.3 (CAS No.: 714-56-7), C.sub.5F.sub.7N.sub.3 (CAS No.: 717-62-4), C.sub.4F.sub.5N.sub.3 (CAS No.: 368-55-8), C.sub.5H.sub.4NI (CAS No.: 5029-67-4), C.sub.5H.sub.4NI (CAS No.: 1120-90-7), C.sub.5H.sub.4NI (CAS No.: 15854-87-2), C.sub.3F.sub.4N.sub.2 (CAS No.: 478693-82-2), C.sub.3F.sub.4N.sub.2 (CAS No.: 478693-82-1), C.sub.3F.sub.4N.sub.2 (CAS No.: 442872-78-8), C.sub.4NF.sub.5 (CAS No.: 445235-48-3), C.sub.5H.sub.4FN (CAS No.: 372-47-4), C.sub.3Cl.sub.3N.sub.3 (CAS No.: 108-77-0), CHCl.sub.4N (CAS No.: 2402-79-1), C.sub.5H.sub.4ClN (CAS No.: 626-60-8), C.sub.5H.sub.5N (CAS No.: 110-86-1), C.sub.4H.sub.4N.sub.2 (CAS No.: 289-95-2), C.sub.4H.sub.4N.sub.2 (CAS No.: 290-37-9), C.sub.3H.sub.3N.sub.3 (CAS No.: 290-87-9), C.sub.6F.sub.7N (CAS No.: 3244-44-8), C.sub.6F.sub.7N (CAS No.: 3146-94-9), C.sub.6F.sub.7N (CAS No.: 440367-82-8), C.sub.5F.sub.6N.sub.2 (CAS No.: 27077-33-4), C.sub.5F.sub.6N.sub.2 (CAS No.: 27077-34-5), C.sub.5F.sub.6N.sub.2 (CAS No.: 27077-35-6), C.sub.5F.sub.6N.sub.2 (CAS No.: 442872-68-6), C.sub.6F.sub.8N.sub.2 (CAS No.: 49616-39-9), C.sub.6F.sub.8N.sub.2 (CAS No.: 67096-98-4), C.sub.6F.sub.8N.sub.2 (CAS No.: 57684-66-9), C.sub.6F.sub.8N.sub.2 (CAS No.: 55827-93-5), C.sub.6F.sub.8N.sub.2 (CAS No.: 54415-66-6), C.sub.6F.sub.8N.sub.2 (CAS No.: 54415-65-5), C.sub.5H.sub.3F.sub.2N (CAS No.: 1513-65-1), C.sub.5H.sub.3F.sub.2N (CAS No.: 84476-99-3), C.sub.5H.sub.3F.sub.2N (CAS No.: 71902-33-5), C.sub.5H.sub.3F.sub.2N (CAS No.: 1513-66-2), C.sub.5H.sub.3F.sub.2N (CAS No.: 34941-90-7), C.sub.5H.sub.3F.sub.2N (CAS No.: 82878-63-5), C.sub.4HF.sub.3N.sub.2 (CAS No.: 696-82-2), C.sub.4HF.sub.3N.sub.2 (CAS No.: 17573-78-3), C.sub.4HF.sub.3N.sub.2 (CAS No.: 17573-79-4), C.sub.4HF.sub.3N.sub.2 (CAS No.: 55215-60-6), C.sub.4HF.sub.3N.sub.2 (CAS No.: 103526-69-8), C.sub.4HF.sub.3N.sub.2 (CAS No.: 2386912-84-9), C.sub.4H.sub.3FN.sub.2 (CAS No.: 675-21-8), C.sub.4H.sub.3FN.sub.2 (CAS No.: 31575-35-6), C.sub.4H.sub.3FN.sub.2 (CAS No.: 4949-13-7), C.sub.4H.sub.3FN.sub.2 (CAS No.: 31462-55-2), C.sub.4H.sub.3FN.sub.2 (CAS No.: 157496-33-8), C.sub.4H.sub.3FN.sub.2 (CAS No.: 157496-32-7), C.sub.4H.sub.2FN.sub.3 (CAS No.: 2169434-14-2), or C.sub.4H.sub.2FN.sub.3 (CAS No.: 2116289-91-7).
8. The method of claim 1, wherein the nitrogen-containing cyclic compound is C.sub.5HF.sub.4N (CAS No.: 2875-18-5).
9. The method of claim 1, wherein the substantially vertical structure is an aperture, via, hole, or trench formed in the film and has an aspect ratio between approximately 1:1 and approximately 500:1.
10. The method of claim 1, wherein the conductive sidewall passivation layer contains at least C, F, and N.
11. The method of claim 1, wherein a nitrogen content contained in the conductive sidewall passivation layer is greater than 2.5%.
12. A method of depositing a conductive polymer layer on a substrate, the method comprising a) exposing the substrate to a vapor of an additive comprising a nitrogen-containing cyclic compound; b) activating a plasma to produce an activated nitrogen-containing cyclic compound; and c) forming the conductive polymer layer on the substrate by depositing at least part of the nitrogen-containing cyclic compound thereon, wherein a nitrogen content contained in the conductive polymer layer is greater than 2.5%.
13. The method of claim 12, wherein the nitrogen-containing cyclic compound has a general formula C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3; X=F, Cl, Br or I (halogens), X=F, Cl, Br or I (halogens), where X?X.
14. The method of claim 12, wherein the nitrogen-containing cyclic compound is C.sub.5HF.sub.4N (CAS No.: 2875-18-5).
15. The method of claim 12, further comprising sequentially or simultaneously exposing the substrate to an oxidizer with the additive at step a), wherein the oxidizer is selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS or combinations thereof.
16. A cyclic method of forming a structure, the structure being formed in a film disposed on a substrate and a patterned mask layer disposed on the film, the method comprising: a) exposing a substrate to a vapor of an additive comprising a nitrogen-containing cyclic compound; b) activating a plasma to produce an activated nitrogen-containing cyclic compound; c) forming a conductive polymer layer on the substrate by depositing at least part of the nitrogen-containing cyclic compound thereon; d) performing a purging process with an inert gas; e) exposing the substrate to an etching gas selected from the nitrogen-containing cyclic compound, a hydrofluorocarbon, hydrocarbon, HBr, HCl, HI, HF, H.sub.2, or combinations thereof; f) activating a plasma to produce an activated etching gas; g) allowing an etching reaction to proceed between the activated etching gas and the film uncovered by the patterned mask layer and the conductive polymer layer to selectively etch the film and the conductive polymer layer from the patterned mask layer, h) performing another purging process with the inert gas; and i) repeating steps a) to h), until a desired depth of the structure in the film is formed.
17. The method of claim 16, wherein a nitrogen content contained in the conductive polymer layer is greater than 2.5%.
18. The method of claim 16, wherein the nitrogen-containing cyclic compound has a general formula C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3; X=F, Cl, Br or I (halogens), X=F, Cl, Br or I (halogens), where X?X.
19. The method of claim 16, wherein the nitrogen-containing cyclic compound is C.sub.5HF.sub.4N (CAS No.: 2875-18-5).
20. The method of claim 16, further comprising sequentially or simultaneously exposing the substrate to an oxidizer with the additive at step a), wherein the oxidizer is selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS or combinations thereof.
21. The method of claim 16, further comprising sequentially or simultaneously exposing the substrate to an inert gas with the etching gas at step e), wherein the inert gas is selected from Ar, Kr, Xe, Ne, N.sub.2, He or combination thereof.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0127] For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:
[0128]
[0129]
[0130]
[0131]
[0132]
[0133]
DESCRIPTION OF PREFERRED EMBODIMENTS
[0134] Disclosed are etching methods of using an additive or an additive chemical or using the additive as a main etching gas to support the formation of a high conductive sidewall polymer passivation layer or a conductive layer on sidewalls of etched structures during HAR etch. The disclosed methods provide using a novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound or etching gas or a new etching material as an additive or as a main etching gas during HAR etch to form the high conductive sidewall polymer passivation layer or the conductive layer. The conductive layer may be a polymer passivation layer. The conductive state of the generated polymer passivation layer reduces charge buildup along the sidewalls to prevent twisting of HAR holes or structures formed by bleeding off the charge and ensuring proper control of critical dimension (CD) variations at low bias power level or less to no bias power. In addition, the generated polymer passivation layer is easily to be cleaned with traditional cleaning processes such as, plasma cleaning methods such as using O.sub.2 or CF.sub.4 or wet cleaning methods using water, organic solvents, or acids such as HF, and will have no extra chamber contamination issues, since volatile byproducts are formed in plasma phase and may be pumped out of an etch chamber rapidly.
[0135] The disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound or etching gas may also be considered as low bias energy etching gas, since with minimized sidewall charge, less plasma bias power is required for reactive ions to reach the bottom of HAR apertures. In addition, the novel aromatic nitrogen-containing fluorocarbons and iodine-containing compounds, additives or etching gases disclosed herein does not contain any hard-to-clean elements, which also minimize chamber contamination issues and reduce tool maintenance/down time. Furthermore, it has been found that the disclosed novel aromatic nitrogen-containing fluorocarbons and iodine-containing compounds, additives or etching gases create conductive polymers by themselves without a need of additional dopant additives. The conductivity of the generated polymer passivation layer is significantly increased as compared to traditional etching gases known in the art.
[0136] The disclosed are also deposition methods of using the disclosed additive or the additive chemical as a deposition precursor to deposit a conductive layer on a surface that may be planer or patterned in a substrate. The disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound or a new etching material as an additive may be used as a main deposition precursor to form the conductive layer on a planar or a patterned surface in semiconductor applications.
[0137] The disclosed methods may be used in a deposition step and the disclosed aromatic nitrogen-containing fluorocarbon and iodine-containing compound used as additives may also be used as a deposition precursor in a cyclic or continuous deposition/etch process to deposit a conductive passivation layer on a surface such as in an ALE process or a TSV etching process, or in other applications for which a conductive polymer might be useful.
[0138] Regarding aromatic nitrogen-containing fluorocarbons and iodine-containing compounds, there are two key differences of having N inside the ring versus outside the ring. N inside the ring (vs C?N, NH, etc.) may be more stabilized to form larger fragments. Thus, preferably, the disclosed novel aromatic nitrogen-containing fluorocarbons and iodine-containing compound or etching gases or the new etching materials contain at least one nitrogen inside the ring or aromatic structure. The rings may open up and form polymer chains. We believe hydrogen on the ring itself may be a key advantage over a fully fluorinated structure. The CH bond is likely to break and this is a known reactive site that may then polymerize. It has been known that hydrogen in the molecule is known to form more polymerizing structure. In some key applications such as etching nitride film it is advantageous to have hydrogen in the molecule. In addition, decreased F:C ratio may increase more cross-linked film, which result in higher selectivity to the mask. Moreover, both H and C?C increases selectivity to the mask and polymer deposition rate, but H may be more favorable with less polymer but improved selectivity. Ion energy may help break the deposition from a double bond molecule more easily than a hydrogen containing molecule, but double bond deposited protection of the mask may be less than the one with hydrogen.
[0139] The disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound comprises cyclic or aromatic nitrogen-containing ring molecules having the formula: C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3; X=F, Cl, Br or I (halogens), X=F, Cl, Br, I (halogens) or CN group, where X?X.
[0140] Alternatively, the disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound comprises cyclic or aromatic nitrogen-containing ring molecules having the formula: C.sub.xH.sub.yF.sub.zI.sub.aN.sub.b, or C.sub.xH.sub.yI.sub.zN.sub.b, or C.sub.xH.sub.yCl.sub.zN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3. For example, when z=0, the disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound includes pyridine (C.sub.5H.sub.5N). More specifically, the disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound excludes the following compounds: C.sub.5F.sub.5N (CAS No.: 700-16-3), C.sub.3F.sub.4N.sub.2 (CAS No.: 478693-81-1), C.sub.4N.sub.2F.sub.4 (CAS No.: 13177-77-0), C.sub.4N.sub.2F.sub.4 (CAS No.: 767-79-3), C.sub.3F.sub.3N.sub.3 (CAS No.: 675-14-9), C.sub.4NF.sub.5 (CAS No.: 445235-48-3), C.sub.3F.sub.4N.sub.2 (CAS No.: 478693-82-2), C.sub.4N.sub.2F.sub.4 (CAS No.: 7627-80-7), C.sub.3F.sub.2N.sub.3Cl (CAS No.: 696-85-5), C.sub.3FN.sub.3Cl.sub.2 (CAS No.: 696-84-4), and C.sub.3N.sub.3Cl.sub.3 (CAS No.: 108-77-0) which are disclosed in patent U.S. Pat. No. 6,508,948B2.
[0141] The disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound is a new etching and deposition material.
[0142] Disclosed etching and deposition composition for forming high conductive sidewall passivation layer during HAR etch may include the following components, each component may be contained one or more. [0143] Etch gas such as fluorocarbon/fluorohydrocarbon selected from C.sub.4F.sub.6, C.sub.4F.sub.8, C.sub.4H.sub.2F.sub.6, CHF.sub.3, CH.sub.2F.sub.2, CH.sub.3F, CF.sub.4, C.sub.2F.sub.6, C.sub.3F.sub.8, SF.sub.6, NF.sub.3, C.sub.2F.sub.4, C.sub.3F.sub.6, C.sub.4F.sub.10, C.sub.5F.sub.8, C.sub.6F.sub.6, C.sub.1-C.sub.6 C.sub.xF.sub.y molecules (x and y are integers), C.sub.2H.sub.5F, C.sub.3H.sub.7F, C.sub.3H.sub.2F.sub.6, C.sub.2HF.sub.5, or combination thereof, or other etching gas such as HBr, HCl, HI, HF or H.sub.2; [0144] Co-reactant or oxidizer selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS; [0145] Inert gas selected from Ar, Xe, Kr, Ne, He, N.sub.2 or combinations thereof; and [0146] New etching and deposition material used as an additive having a general formula of C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3; X=F, Cl, Br or I (halogens), X=F, Cl, Br, I (halogens) or CN group, where X?X, or C.sub.xH.sub.yF.sub.zI.sub.aN.sub.b, or C.sub.xH.sub.yI.sub.zN.sub.b, or C.sub.xH.sub.yCl.sub.zN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3, wherein the new etching material contains at least 1 double C?C bonds, a cyclic or aromatic structure and at least one nitrogen that is contained within the cyclic or aromatic structure, wherein the new etching material excludes the following compounds: C.sub.5F.sub.5N (CAS#700-16-3), C.sub.3F.sub.4N.sub.2 (CAS #478693-81-1), C.sub.4N.sub.2F.sub.4 (CAS #13177-77-0), C.sub.4N.sub.2F.sub.4 (CAS #767-79-3), C.sub.3F.sub.3N.sub.3 (CAS #675-14-9), C.sub.4NF.sub.5 (CAS #445235-48-3), C.sub.3F.sub.4N.sub.2 (CAS #478693-82-2), C.sub.4N.sub.2F.sub.4 (CAS #7627-80-7), C.sub.3F.sub.2N.sub.3Cl (CAS #696-85-5), C.sub.3FN.sub.3Cl.sub.2 (CAS #696-84-4), and C.sub.3N.sub.3Cl.sub.3 (CAS #108-77-0).
[0147] Some of the exemplary molecules of the disclosed novel aromatic nitrogen-containing fluorocarbon and iodine-containing compound or new etching and deposition material may be used as the additive with CAS No. and boiling points are shown in Table 1.
TABLE-US-00001 TABLE 1 Mol. Structure Mol. Formula CAS No. Boiling Point
[0148] The molecules identified in the Table 1 are novel for their use as an etching gas or an additive and have not been mentioned in any identified references for using as an etching gas or an additive. U.S. Pat. No. 6,508,948 discloses aromatic N-containing molecules but all molecules listed do not contain hydrogen. The molecules in Table 1 containing hydrogen are considered advantageous for applications requiring etch of SiN films such as HAR etch of ONON channels for 3D NAND application. In this regard, the N-containing molecules may support the tuning of the SiO and SiN etching rate which may help provide a smooth sidewall and less scalloping. In addition, U.S. Pat. No. 6,508,948 does not give a formula for these molecules, just the general term perfluorinated heteroaromatic amines, and use the term hydrocarbons that means containing hydrogen. It has not been mentioned in the art that these molecules may produce highly conductive sidewall polymers. U.S. Pat. No. 6,508,948 does not disclose use of Kr or Xe.
[0149] The addition of hydrogen into the structure of the molecules is well known to enhance the etch rate of SiN which can be critical for 3D NAND etching of alternating layers of SiO and SiN. However, the addition of H may play two roles. This may be important to control the etching rate of SiO and SiN to prevent scalloping in the sidewall of a HAR structure in ONON 3DNAND etching application. As such controlling the etching rate of each material is critical. A material that etches one material faster than the other could be used as a tuning gas to increase or decrease the etch rate of one material to result in a smoother sidewall.
[0150] In addition, specifically, some of the exemplary N-containing aromatic molecules without containing H listed in Table 1 may be used as an additive are shown in Table 2, which shows the permutations of F to CF.sub.3 substitution and C to N substitution.
TABLE-US-00002 TABLE 2 F to CF.sub.3 substitution .fwdarw. no CF.sub.3 terminal CF.sub.3 (CF.sub.3).sub.2 (CF.sub.3).sub.3 C to N N.sub.1 C.sub.5F.sub.5N C.sub.6F.sub.7N substitution N.sub.2 C.sub.4F.sub.4N.sub.2 C.sub.5F.sub.6N.sub.2 C.sub.6F.sub.8N.sub.2 .fwdarw. N.sub.3 C.sub.3F.sub.3N.sub.3 C.sub.4F.sub.5N.sub.3 C.sub.5F.sub.7N.sub.3 C.sub.6F.sub.9N.sub.3 C.sub.5F.sub.7N.sub.3 C.sub.6F.sub.9N.sub.3
[0151] Specifically, some of the exemplary N-containing aromatic molecules containing H listed in Table 1 that may be used as an additive are shown in Table 3, which shows the permutations of F to H substitution and C to N substitution.
TABLE-US-00003 TABLE 3 F to H substitution .fwdarw. H H.sub.2 H.sub.3 H.sub.4 C to N N.sub.1 C.sub.5HF.sub.4N C.sub.5H.sub.2F.sub.3N C.sub.5H.sub.3F.sub.2N C.sub.5H.sub.4FN substitution N.sub.2 C.sub.4HF.sub.3N.sub.2 C.sub.5H.sub.2F.sub.2N.sub.2 C.sub.4H.sub.3FN.sub.2 C.sub.4H.sub.4N.sub.2 .fwdarw. N.sub.3 C.sub.3HF.sub.2N.sub.3 C.sub.4H.sub.2FN.sub.3 C.sub.3H.sub.3N.sub.3
[0152] The disclosed new etching and deposition materials maybe used as the additive are suitable to engineer the passivation layer property formed on sidewalls of the HAR holes/trenches. The sidewall passivation and downward etch occur simultaneously. The passivation layer may be formed from the carbon source in plasma etching gas, from the reactions between etching gases and the materials being exposed, or from the redeposition of byproduct from the etch process. The additives to the etchant strongly affect the chemical composition of the sidewall passivation by introducing conductive elements and/or chemical bonds, thereby positively affect the conductivity of the sidewall passivation. Over the course of plasma etching, the potential of the bottom of an etched structure charges positively while the sidewalls charge negatively, thereby building undesired local electrical fields within the etched structure. Only energetic ions with energy larger than the potential difference along a local electrical field may reach to bottom. Charges on the sidewall dissipates fast as conductivity of sidewall passivation increases. The required bias power is below a baseline process.
[0153] The disclosed etching gases may be fluorocarbons/hydrofluorocarbons. Exemplary disclosed fluorocarbons/hydrofluorocarbons include C.sub.4F.sub.6, C.sub.4F.sub.8, C.sub.4H.sub.2F.sub.6, CHF.sub.3, CH.sub.2F.sub.2, CH.sub.3F, CF.sub.4, C.sub.2F.sub.6, C.sub.3F.sub.8, SF.sub.6, NF.sub.3, C.sub.2F.sub.4, C.sub.3F.sub.6, C.sub.4F.sub.10, C.sub.5F.sub.8, C.sub.6F.sub.6, C.sub.1-C.sub.6 C.sub.xF.sub.y molecules (x and y are integers), C.sub.2H.sub.5F, C.sub.3H.sub.7F, C.sub.3H.sub.2F.sub.6, C.sub.2HF.sub.5, or combination thereof. The disclosed fluorocarbons/hydrofluorocarbons etching gases are suitable for etching silicon-containing films that include a layer of silicon oxide (SiO), silicon nitride (SiN), pure silicon (Si) such as crystalline Si, poly-silicon (p-Si or polycrystalline Si); amorphous silicon, low-k SiCOH, SiOCN, SiC, SiON, Si.sub.aO.sub.bH.sub.cC.sub.dN.sub.e, where a>0; b, c, d and e?0; metal containing films (e.g., copper, cobalt, ruthenium, tungsten, indium, platinum, palladium, nickel, ruthenium, gold, etc.), or the like. The silicon-containing film may also include alternating SiO and SiN (ONON) layers or SiO and p-Si (OPOP) layers. The silicon-containing films contain O and/or N. The silicon-containing films may also include dopants, such as B, C, P, As, Ga, In, Sn, Sb, Bi and/or Ge, and combinations thereof. The disclosed etching gas may be other etching gas such as HBr, HCl, HI, HF, or H.sub.2.
[0154] The disclosed new etching and deposition materials used as the additive and the disclosed fluorocarbons/hydrofluorocarbon etching gases are provided at greater than 95% v/v purity, preferably at greater than 99.99% v/v purity, and more preferably at greater than 99.999% v/v purity.
[0155] The disclosed new etching and deposition materials used as the additive and the disclosed fluorocarbons/hydrofluorocarbon etching gases contain less than 1% by volume trace gaseous impurities, with less than 150 ppm by volume of impurity gases, such as N.sub.2 and/or H.sub.2O and/or CO.sub.2, contained in said trace gaseous impurities. Preferably, the water content in the additive is less than 20 ppmw by weight. The purified additive product may be produced by distillation and/or passing the gas or liquid through a suitable adsorbent, such as a 4 ? molecular sieve.
[0156] The disclosed new etching and deposition materials used as the additive and the disclosed fluorocarbons/hydrofluorocarbon etching gases contain less than 10% v/v, preferably less than 1% v/v, more preferably less than 0.1% v/v, and even more preferably less than 0.01% v/v of any of its isomers, which may be purified by distillation of the gas or liquid to remove isomers and may provide better process repeatability.
[0157] The disclosed new etching and deposition materials used as the additive and/or the disclosed fluorocarbons/hydrofluorocarbon etching gases selectively etch the silicon-containing layers from a buried landing layer or material which is a metal layer located at the bottom of the structure to be etched in most applications. The disclosed fluorocarbons/hydrofluorocarbons do not etch metal landing layers. The buried landing layer may be an etching stop layer or a diffusion barrier layer. Materials of the metal landing layers may be a tungsten metal worldline in a 3D NAND structure and/or another metal such as W, Cu, Al, Ru, Pt, Ti, Ta, Ni, Co, Mo, Mn, Pd, Ir, Nb, Cr, Rh, V, Au, Ag or combination thereof and/or etch stop layers such as metals or metal oxides or nitrides layer such as AlO, WO, HfO, TiO, TaO, InO, CrO, RuO, CoO, MoO, ZrO, SnO TiN, TaN, HfN, AlN, WN, MON, NIN, NbN, CrN, RuN, CON, ZrN, SnN or combination thereof etc.
[0158] The disclosed new etching and deposition materials used as the additive and/or the disclosed etching gases such as fluorocarbons/hydrofluorocarbon may be used to plasma etch silicon-containing films on a substrate. The disclosed plasma etching method may be useful in the manufacture of semiconductor devices such as NAND or 3D NAND gates or Flash or DRAM memory or transistors such as fin-shaped field-effect transistor (FinFET), Gate All Around(GAA)-FET, Nanowire-FET, Nanosheet-FET, Forksheet-FET, Complementary FET (CFET), Bulk complementary metal-oxide-semiconductor (Bulk CMOS), MOSFET, fully depleted silicon-on-insulator (FD-SOI) structures. The disclosed new etching and deposition materials used as the additive and/or the disclosed etching gases such as fluorocarbons/hydrofluorocarbon may be used in other areas of applications, such as different front end of the line (FEOL) and back end of the line (BEOL) etch applications. Additionally, the disclosed new etching and deposition materials used as the additive and/or the disclosed etching gases such as fluorocarbons/hydrofluorocarbon may also be used for etching Si in 3D through silicon via (TSV) etch applications for interconnecting memory to logic on a substrate and in MEMS applications.
[0159] The disclosed etching method includes providing a reaction chamber having a substrate disposed therein. The reaction chamber may be any enclosure or chamber within a device in which etching methods take place such as, and without limitation, reactive ion etching (RIE), CCP with single or multiple frequency RF sources, inductively coupled plasma (ICP), or microwave plasma reactors, or other types of etching systems capable of selectively removing a portion of the silicon-containing film or generating active species or depositing films. Preferred chamber is a CCP chamber. One of ordinary skill in the art will recognize that the different plasma reaction chamber designs provide different electron temperature control. Suitable commercially available plasma reaction chambers include but are not limited to the Lam Research Dual CCP reactive ion etcher Dielectric etch product family sold under the trademark Flex? or the Tokyo Electron Tactras? or Episode? UL. The RF power in such may be pulsed to control plasma properties and thereby improving the etch performance (selectivity and damage) further.
[0160] The reaction chamber may contain one or more than one substrate. For example, the reaction chamber may contain from 1 to 200 silicon wafers having from 25.4 mm to 450 mm diameters. The substrates may be any suitable substrates used in semiconductor, photovoltaic, flat panel or LCD-TFT device manufacturing. Examples of suitable substrates include wafers, such as silicon, silica, glass, Ge, SiGe, GeSn, InGaAs, GaSb, InP, or GaAs wafers. The wafer will have multiple films or layers on it from previous manufacturing steps, including silicon-containing films or layers. The layers may or may not be patterned. Examples of suitable layers include without limitation silicon (such as amorphous silicon, p-Si, crystalline silicon, any of which may further be p-doped or n-doped with B, C, P, As, Ga, In, Sn, Sb, Bi and/or Ge), silica, silicon nitride, silicon oxide, silicon oxynitride, Si.sub.aO.sub.bH.sub.cC.sub.dN.sub.e, (wherein a>0; b, c, d, e?0), Ge, SiGe, GeSn, InGaAs, GaSb, InP; mask layer materials such as amorphous carbon with or without dopants, antireflective coatings, photoresist materials, a metal oxide, such as AlO, TiO, HfO, ZrO, SnO, TaO etc. or a metal nitride layer such as AlN, ZrN, SnN, HfN, titanium nitride, tantalum nitride etc. or combinations thereof; etch stop layer materials such as silicon nitride, polysilicon, crystalline silicon, silicon carbide, SiON, SiCN or combinations thereof, device channel materials such crystalline silicon, epitaxial silicon, doped silicon, Si.sub.aO.sub.bH.sub.cC.sub.dN.sub.e, (wherein a>0; b, c, d, e?0) or combinations thereof. The silicon oxide layer may form a dielectric material, such as an organic based or silicon oxide based low-k dielectric material (e.g., a porous SiCOH film). An exemplary low-k dielectric material is sold by Applied Materials under the trade name Black Diamond II or III. Additionally, layers comprising tungsten or noble metals (e.g. platinum, palladium, rhodium or gold) may be used. Furthermore, examples of the silicon-containing films may be Si.sub.aO.sub.bH.sub.cC.sub.dN.sub.e, (wherein a>0; b, c, d, e?0). Throughout the specification and claims, the wafer and any associated layers thereon are referred to as substrates.
[0161] In the disclosed etching methods, the plasma process time may vary from 0.01 s to 10000 s. Preferably from 1 s to 30 s. N.sub.2 purge time may vary from 1 s to 10000 s. Preferably 10 s to 60 s.
[0162] The disclosed etching method includes pumping the reactor chamber down to a high vacuum after placing the substrate into the chamber and before introducing the disclosed fluorocarbons/hydrofluorocarbons and/or disclosed new etching and deposition materials into the chamber. The high vacuum may range from 0.01 mTorr-10 mTorr.
[0163] The temperature of the reactor chamber may be controlled by either controlling the temperature of the substrate holder or controlling the temperature of the reactor wall. Devices used to heat the substrate are known in the art. The reactor wall is heated to a sufficient temperature to prevent condensation on the wall or the reactor chamber, especially when a shower head reactor is used, in which the substrate temperature is higher than the temperature of the wall. A non-limiting exemplary temperature range to which the reactor wall may be heated includes a range from approximately ?100? C. (LN temp) to approximately 500? C. , preferably from approximately 20? C. to approximately 150? C., more preferably from 20? C. to approximately 110? C.
[0164] The temperature and the pressure within the reaction chamber are held at conditions suitable for the silicon-containing film to react with the activated etching gas or the activated etching components. For instance, The pressure within the reaction chamber are held at conditions suitable for an etchant or a process gas the portions of the substrate not being covered by the patterned mask layer. Here the etchant or the process gas may include a hydrofluorocarbon or fluorocarbon etching gas, an additive, co-reactants, etc. For instance, the pressure in the reactor may be held between approximately 1 mTorr and approximately 100 Torr, preferably between approximately 1 mTorr and approximately 50 Torr, more preferably between approximately 1 mTorr and approximately 10 Torr, even more preferably between approximately 1 mTorr and approximately 50 mTorr, as required by the etching parameters. Likewise, the substrate temperature in the chamber may range between approximately ?110? C. to approximately 2000? C., preferably between approximately ?70? C. to approximately 1500? C., more preferably between approximately ?20? C. to approximately 1000? C., even more preferably between approximately 25? C. to approximately 700? C., even more preferably between approximately 25? C. to approximately 500? C., and even more preferably between approximately 25? C. to approximately 50? C. Chamber wall temperatures may range from approximately 25? C. to approximately 100? C. depending on the process requirements. In a cryogenic etch process the preferred temperature will be less than ?20? C.
[0165] In one embodiment, each component of the disclosed etching and deposition composition may be introduced to the chamber at a flow rate ranging from approximately 1 sccm to approximately 10 slm. Preferably 1 sccm to 100 sccm. The inert gas may be introduced to the chamber at a flow rate ranging from approximately 1 sccm to approximately 10 slm. Preferably 10 sccm to 200 sccm. One of ordinary skill in the art will recognize that the flow rate may vary from tool to tool.
[0166] Etching and deposition conditions may change during the etching process. For example parameters such as gas flow, plasma power, pressure, temperature may be higher or lower during the beginning part of the etch as compared to the end part of the etch near the bottom of the hole or trenches. Alternatively, different etching gases may be added at different points in the etch to improve the performance such as to reduce or enhance the polymer deposition rate.
[0167] The disclosed etching and deposition methods provide high selectivity to mask layers, photoresist, etch stop layers and device channel materials and no profile distortion in HAR structures, such as those having an aspect ratio ranging from 1:1 to 500:1 such as DRAM and 3D NAND structures and contact etch applications. The disclosed etching methods are suitable for etching HAR patterned structure having an aspect ratio between approximately 1:1 and approximately 500:1. Alternatively, the disclosed etching methods are suitable for etching HAR patterned structure having an aspect ratio between approximately 1:1 and approximately 200:1, an aspect ratio between approximately 1:1 and approximately 20:1, an aspect ratio between approximately 21:1 and approximately 200:1, an aspect ratio between approximately 1:1 and approximately 60:1, or an aspect ratio between approximately 61:1 and approximately 500:1.
[0168] The disclosed etching and deposition methods provide high selectivity of one material vs multiple other materials and could be used for multicolor etching or other selective etching processes whereby etch of one material is highly selective to multiple other materials. This would also enable tuning the etching process for the SiO and SiN etching rate by adding the N-containing gas into an etching gas mixture to prevent scalloping and result in a smooth sidewall.
[0169] The disclosed etching and deposition methods comprise the steps of [0170] 1) Positioning a patterned substrate with a-C mask on a substrate holder in a plasma processing chamber, such as a CCP plasma etcher; [0171] 2) Pumping the processing chamber down to a high vacuum; [0172] 3) May or may not introducing an etching gas such as fluorocarbon/fluorohydrocarbon (C.sub.xH.sub.yF.sub.z, x, y, z are integers), HBr, HCl, HI, HF, or H.sub.2 into the chamber and allowing it to equilibrate; [0173] 4) May or may not include introducing an inert gas selected from Ar, Kr, Xe, Ne, N.sub.2, He into the chamber and allowing it to equilibrate; [0174] 5) Introducing an additive having a general formula of C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b, where x=3-6; y=0-4; z=0-8; a=0-1; b=1-3; X=F, Cl, Br or I (halogens), X=F, Cl, Br, I (halogens) or CN group, where X?X, or C.sub.xH.sub.yF.sub.zI.sub.aN.sub.b (wherein x=3-6; y=0-4; z=0-8 a=0-1; b=1-3) into the chamber and allowing it to equilibrate; [0175] 6) May or may not include introducing a co-reactant or an oxidizer into the chamber and allowing it to equilibrate; [0176] 7) Turning on a source power to ignite plasma; [0177] 8) May or may not include turning on a bias power to set plasma bias; [0178] 9) Keeping the plasma process running for a specified time; and [0179] 10) Turning all plasma source power off.
[0180] In the above etching steps, the flow rate of C.sub.xH.sub.yX.sub.zX.sub.aN.sub.b or C.sub.xH.sub.yF.sub.zI.sub.aN.sub.b, inert gas, co-reactant, and other gases such as C.sub.xH.sub.yF.sub.z or other reactants are chosen based on the specific process regime common to the process. The plasma power (bias and source) may be pulsed or continuous. The gas flows may be a continuous flow or a pulsing flow. In addition, a cyclic process could be performed separating the flow of the depositing gas and the co-reactant or inert gas to better control the polymer deposition process and the etching process similar to the concept of atomic layer etching. In the cyclic process, the pressure, flow and plasma configuration for each of the individual steps may be customized for source power, bias power, pulsing or continuous mode.
[0181] The co-reactant may be an oxidizer selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS or combinations thereof. The vapor of the additive and the co-reactant may be mixed together prior to introduction into the reaction chamber. The oxidizer may comprise between approximately 0.01% v/v to approximately 99.99% v/v of the mixture introduced into the chamber (with 99.99% v/v representing introduction of almost pure oxidizer for the continuous introduction alternative).
[0182] Alternatively, the co-reactant may be introduced continuously into the chamber and the vapor of the disclosed additive molecules and the vapor of the fluorocarbon or hydrofluorocarbon etching gas or HBr, HCl, HI, HF, or H.sub.2 etching gas may be introduced into the chamber in pulses. The co-reactant may comprise between approximately 0.01% v/v to approximately 99.99% v/v of the mixture introduced into the chamber (with 99.99% v/v representing introduction of almost pure co-reactant for the continuous introduction alternative).
[0183] Each component, molecule, gas or vapor in the disclosed etching and deposition methods may be supplied either in a cylinder or in a bubbler with a dip tube. The molecule may be bubbled with an inert gas such as Ar, where the bubbler may be heated and lines may be heated to increase the vapor delivered to the chamber. The bubbler may be located close to the tool to reduce the likelihood of condensation in the line and the pressure drop across long delivery lines. The bubbler may also not have a dip tube and instead use just a vapor draw and sweep gas configuration with an inert gas such as Ar. Other common methods of delivery of low vapor pressure molecules including methods such as vaporizers could be used.
[0184] The disclosed additive and etching gas such as fluorocarbon or hydrofluorocarbon etching gases or HBr, HCl, HI, HF, or H.sub.2 etching gas may be, respectively, mixed with other gases either prior to introduction into the reaction chamber or inside the reaction chamber. Preferably, the gases may be mixed prior to introduction to the chamber in order to provide a uniform concentration of the entering gas.
[0185] The vapor or gas of each component or molecule in the disclosed etching and deposition methods are activated by plasma to produce an activated etching gas. The plasma decomposes the additive, etching gas, oxidizer and inert gas into radical form (i.e., the activated additive, etching gas, oxidizer and inert gas). The plasma may be generated by applying RF or DC power. The plasma may be generated with a RF power ranging from about 25 W to about 100,000 W. The plasma may be generated remotely or within the reactor itself. The plasma may be generated in dual CCP or ICP mode with RF applied at both electrodes. RF frequency of plasma may range from 100 KHz to 1 GHz. Different RF sources at different frequency may be coupled and applied at same electrode. Plasma RF pulsing may be further used to control molecule fragmentation and reaction at substrate. One of skill in the art will recognize methods and apparatus suitable for such plasma treatment.
[0186] A quadrupole mass spectrometer (QMS), optical emission spectrometer, FTIR, or other radical/ion measurement tools may measure the activated additive, etching gas, oxidizer and inert gas from the chamber exhaust to determine the types and numbers of species produced. If necessary, the flow rate of the additive, etching gas, oxidizer and/or inert gas may be adjusted to increase or decrease the number of radical species produced.
[0187] The disclosed new etching and deposition materials used as the additive and/or the disclosed etching gas such as fluorocarbons/hydrofluorocarbon or HBr, HCl, HI, HF, or H.sub.2 etching gases may be mixed with other gases or co-reactants either prior to introduction into the reaction chamber or inside the reaction chamber. Preferably, the gases may be mixed prior to introduction to the chamber in order to provide a uniform concentration of the additive and the entering gas.
[0188] In another alternative, the vapor of the disclosed new etching and deposition materials used as the additive and/or the disclosed etching gas such as fluorocarbons/hydrofluorocarbon or HBr, HCl, HI, HF, or H.sub.2 etching gases may be, respectively, introduced into the chamber independently from the other gases, such as when two or more of the gases react or are easier to deliver independently.
[0189] In the deposition process, the bias power could be set to zero power to allow deposition of a conducting polymer layer but may also be turned to a power greater than zero. A bias power may impact the properties of the resulting deposited film.
[0190] A patterned substrate may contain silicon-containing film, a patterned a-C mask layer, an antireflective coating layer, and a photoresist layer may be displaced on top of the silicon-containing film. In the disclosed etching method, the silicon-containing films and the activated etching gas, i.e., the activated additive gas and/or etching gas such as fluorocarbon or hydrofluorocarbon or HBr, HCl, HI, HF, or H.sub.2 etching gas, react to form volatile by-products that are removed from the reaction chamber. The patterned a-C mask, antireflective coating, and photoresist layers are less reactive with the activated etching gas. Thus, the activated etching gas selectively reacts with the silicon-containing film to form volatile by-products. The reactions between the silicon-containing film and the activated etching gas result in anisotropic removal of the silicon-containing film from the substrate. Atoms of nitrogen, oxygen, and/or carbon may also be present in the silicon-containing film. The removal is due to a physical sputtering of silicon-containing film from plasma ions (accelerated by the plasma) and/or by chemical reaction of plasma species to convert Si to volatile species, such as SiFx, wherein x ranges from 1-4.
[0191] The disclosed etching and deposition method may be applied to etching Si-containing layers, such as alternating layers of different Si materials such as SiO.sub.2 and SiN selective vs a mask layer for example a-C or doped a-C, high aspect ratio etching and 3D NAND, deposition of conducting polymer layers, etc.
[0192] The disclosed etching and deposition method with the additive produces apertures such as channel holes, gate trenches, staircase contacts, capacitor holes, contact holes, contact etch, slit etch, self-aligned contact, self-aligned vias, super vias etc., in the silicon-containing films. The resulting apertures may have an aspect ratio ranging from approximately 1:1 to approximately 500:1, preferably from approximately 20:1 to approximately 500:1, more preferably from 20:1 to 400:1; and a diameter ranging from approximately 5 nm to approximately 500 nm, preferably less than 100 nm. For example, one of ordinary skill in the art will recognize that a channel hole etch produces apertures in the silicon-containing films having an aspect ratio greater than 50:1.
[0193] Typical materials that need to be etched may be SiO. A process of etching SiO may be relevant to etching trenches in Borophosphosilicateglass (BPSG), Tetraethylorthosilicate (TEOS), or low deposition rate TEOS (LDTEOS). An etch stop layer may be silicon nitride or silicon oxygen nitride (SiON) or poly silicon. A mask material used may be a-C, p-Si, or photo resist materials. Herein, the disclosed nitrogen-containing aromatic or ring structure additive etching compounds are applied to etch SiO, SiN, p-Si and/or a-C substrate films.
[0194] The disclosed etching and deposition method with the additive may deposit a highly conductive film of thickness ranging from 0.1 nm to 1 micron depending on the application. The deposition method may be used in a cyclic process where the polymer is deposited using the additive gas and an etching step with an etching gas is used to remove material. The material deposited on may be but not limited to a silicon based material or other materials such as carbon, metals, III-V. The deposition method may be used in a cyclic process such as atomic layer etching process or a Bosch etch process. The cyclic etch process may have an inert gas purge step before and after the deposition and etching step. For example, a Bosch etch process for TSV etch application may involve a method of depositing a highly conductive film on a silicon surface, purging the chamber with an inert gas, etching the silicon surface and the conductive film using an etching gas such as C.sub.4F.sub.8 and then purging the chamber with an inert gas. This cycle may be repeated until a desired depth of a structure is formed.
[0195] In one embodiment, the disclosed deposition method may be applied to deposit a conductive polymer passivation layer on a planar surface or a patterned surface on a substrate. The patterned surface may be sidewalls of an etched structure, such as an aperture, via, hole or trench, in a substrate, in which the etched structure is formed in a film disposed on the substrate and a patterned mask layer disposed on the film. The disclosed deposition method of depositing the conductive polymer passivation layer comprises: [0196] a) exposing the substrate to a vapor of an additive comprising a nitrogen-containing cyclic compound; [0197] b) activating a plasma to produce an activated nitrogen-containing cyclic compound; and [0198] c) forming the conductive polymer passivation layer on the substrate by depositing at least part of the nitrogen-containing cyclic compound thereon, wherein the nitrogen-containing cyclic compound reduces a charge that builds up along the substrate forming the conductive polymer passivation layer thereon, wherein a nitrogen content contained in the conductive polymer layer is greater than 2.5%.
[0199] At step a), the substrate may be exposed to a co-reactant or an oxidizer sequencailly or simultaneously with the additive. The oxidizer is selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS or combinations thereof.
[0200] Furthermore, in one embodiment, the disclosed etching and deposition method may be a cyclic etching and deposition method that may be applied to deposit a conductive polymer passivation layer on sidewalls of an etched structure, such as an aperture, via, hole or trench, in a substrate, in which the etched structure is formed in a film disposed on the substrate and a patterned mask layer disposed on the film. The disclosed cyclic etching and deposition method of forming a structure on a substrate comprises: [0201] a) exposing the substrate to a vapor of an additive comprising a nitrogen-containing cyclic compound; [0202] b) activating a plasma to produce an activated nitrogen-containing cyclic compound; and [0203] c) forming the conductive polymer passivation layer on the substrate by depositing at least part of the nitrogen-containing cyclic compound thereon, wherein the nitrogen-containing cyclic compound reduces a charge that builds up along the substrate forming the conductive polymer passivation layer thereon; [0204] d) performing a purging process with an inert gas such as Ar; [0205] e) exposing the substrate to an etching gas such as hydrofluorocarbon or hydrocarbon etching gas, HBr, HCl, HI, HF, or H.sub.2, the vapor of the nitrogen-containing cyclic compound, or combinations thereof; [0206] f) activating a plasma to produce an activated etching gas such as hydrofluorocarbon or hydrocarbon etching gas, HBr, HCl, HI, HF, or H.sub.2, the activated nitrogen-containing cyclic compound, or combinations thereof; [0207] g) allowing an etching reaction to proceed between the film uncovered by the patterned mask layer and the conductive polymer layer and the activated hydrofluorocarbon or hydrocarbon etching gas, the activated nitrogen-containing cyclic compound, or combination thereof, to selectively etch the film and the conductive polymer layer from the patterned mask layer; [0208] h) performing another purging process with the inert gas such as Ar; [0209] i) repeating steps a) to h), until a desired depth of the structure in the film is formed.
[0210] Here note, a purging step using an inert gas such as N.sub.2 or Ar may be optionally applied between the exposures at steps a) and e). That is, in some embodiments, step d) and step h) may be eliminated. At step a), the substrate may be exposed to an inert gas, such as Ar, and/or a co-reactant or an oxidizer selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS, simultaneously or sequentially with the additive. Then an activated inert gas and/or activated oxidizer are produced if the oxidizer and inert gas are applied. At step e), the substrate may be exposed to an inert gas, such as Ar, and/or a co-reactant or an oxidizer selected from O.sub.2, CO, CO.sub.2, NO, NO.sub.2, N.sub.2O, SO.sub.2, H.sub.2S, or COS, simultaneously or sequentially with the etching gas such as hydrofluorocarbon, hydrocarbon, HBr, HCl, HI, HF, or H.sub.2 etching gas and/or the nitrogen-containing cyclic compound. In this case, an activated inert gas and/or an activated co-reactant are then produced if the inert gas and/or the co-reactant are applied. Besides Ar used in the purging process, other inert gas selected from Xe, Kr, Ne, He, N.sub.2 or combinations also may be used.
[0211] The disclosed method may deposit a high nitrogen content polymer containing C, F, and N and potentially other elements such as O and Si. The nitrogen content is greater than 2.5%. High nitrogen content polymer may be beneficial in HAR etching process. The high nitrogen content polymer may be deposited on the sidewall of the HAR structure during the etching process using the nitrogen containing etching gases.
[0212] The disclosed method to etch a HAR structure may use an etching process where the process conditions are changed as the etching is getting deeper and deeper in the structure. For example, the etch recipe may include different process conditions during the etching at the beginning, middle and end corresponding to etching the top, middle and bottom portions of the pattern structure. Accordingly, the disclosed methods may be used to etch only portions of the HAR structure. The disclosed molecules may be used to etch only during the etch of the top, or the middle or the bottom of the pattern structure depending on the etching properties of the etchant or molecule. For example, it may be beneficial to have a highly conductive passivation sidewall polymer when etching the bottom of the structure. It may be beneficial to have a high nitrogen content polymer or plasma during the etch of the top, the middle or the bottom of the pattern structure.
EXAMPLES
[0213] The following non-limiting examples are provided to further illustrate embodiments of the invention. However, the examples are not intended to be all inclusive and are not intended to limit the scope of the inventions described herein.
Example 1
[0214]
[0215] Test condition of C.sub.5F.sub.5N: 5 sccm of C.sub.5F.sub.5N (CAS No.: 700-16-3), 250 sccm of Ar and varying flow of O.sub.2 were flown into a 200 mm dual CCP plasma etch chamber. The plasma power was 750 W/1500 W for 60 s.
[0216] Test condition of C.sub.3F.sub.3N.sub.3 and C.sub.5HF.sub.4N: 15 sccm of etch gas, 150 sccm of Ar and varying flow of O.sub.2 were flowed into a 300 mm dual CCP plasma etch chamber. The plasma power was 700 W/6000 W for 60 s.
[0217] Test condition of C.sub.4F.sub.8: 25 sccm of etch gas, 150 sccm of Ar and varying flow of O.sub.2 were flowed into a 300 mm dual CCP plasma etch chamber. The plasma power was 700 W/6000 W for 60 s.
[0218]
TABLE-US-00004 TABLE 4 O.sub.2 Flow Rate Etch Rate Selectivity (sccm) SiO.sub.2 SiN p-Si a-C SiO.sub.2:a-C SiO.sub.2:p-Si 0 70.3 0 ?40 ?38.4 10 56.3 40 0 42.4 13.3 98.6 20 586.9 90 30 115.5 5.1 18.4 30 506.6 110 35 128.8 3.9 15.2 40 381.2 160 40 148.3 2.6 8.9
[0219] The trend for SiO.sub.2 vs a-C etch selectivity: C.sub.5HF.sub.4N>C.sub.4F.sub.8>C.sub.3F.sub.3N.sub.3. Results suggest C.sub.5HF.sub.4N is more polymerizing than C.sub.3F.sub.3N.sub.3 even though their C:F ratio are very similar. Especially at an etch gas vs O.sub.2 flow ratio of 1.5, C.sub.5HF.sub.4N demonstrates infinite selectivity of SiO.sub.2 to p-Si and a-C thin films but also at a ratio of 0.75 there is an increase in selectivity vs C.sub.3F.sub.3N.sub.3 (3.6 vs 2.8). Based on these it may be concluded that the selectivity of SiO.sub.2 vs a-C may not be driven by the C:F ratio as demonstrated by the higher selectivity by C.sub.4F.sub.8 VS C.sub.3F.sub.3N.sub.3. As the results show the N-containing aromatic molecules may be beneficial under certain process conditions such as low-O.sub.2 flow rate, to have high selective etch of SiO vs other materials including SiN, p-Si and a-C as compared to C.sub.4F.sub.8. But C.sub.5HF.sub.4N shows a wider process window for infinite selectivity of SiO vs other films as compared to C.sub.3F.sub.3N.sub.3.
[0220] Due to H-containing structure of C.sub.5HF.sub.4N, C.sub.5HF.sub.4N should be also a promising candidate for ONON etch. It may be seen that the SiO.sub.2:SiN etch rate for C.sub.5HF.sub.4N is closer to 1:1 than for C.sub.3F.sub.3N.sub.3 at 20 sccm of O.sub.2 where the a-C selectivity is 3.6 vs 2.8 showing a benefit of C.sub.5HF.sub.4N vs C.sub.3F.sub.3N.sub.3. Hydrogen is not required to etch SiN as may be seen for C.sub.4F.sub.8 and C.sub.3F.sub.3N.sub.3 but may enhance the etch rate.
Example 2
[0221] Polymer conductivity comparison between C.sub.5HF.sub.4N and molecules known in the art (US 2019P00634): C.sub.4F.sub.6, C.sub.4F.sub.8, C.sub.3F.sub.3N.sub.3, C.sub.6F.sub.6, C.sub.4H.sub.2F.sub.6 and a silicon doping gas, is shown in
TABLE-US-00005 TABLE 5 Chemistry Current (A) @ 0.3 V Aromatic? (Y/N) C.sub.4F.sub.8 4E?11 N C.sub.4F.sub.6 2E?11 N C.sub.6F.sub.6 3E?10 Y C.sub.3F.sub.3N.sub.3 2E?10 Y C.sub.4H.sub.2F.sub.6 4E?11 N C.sub.4H.sub.2F.sub.6 + silicon dopant gas 4E?8 N C.sub.5HF.sub.4N 1E?5 Y
[0222] C.sub.4F.sub.8 is a traditional etching gas with all CC single bonds. C.sub.4F.sub.6 has two C?C double bonds. However, the conductivities of C.sub.4F.sub.8 and C.sub.4F.sub.6 are similar; therefore, C.sub.4F.sub.8 and C.sub.4F.sub.6 have very little difference in sidewall polymer conductivity and in ability to reduce sidewall charge buildup. Similarly, C.sub.4H.sub.2F.sub.6 has one C?C double bond and shows similar conductivity as C.sub.4F.sub.8 and C.sub.4F.sub.6. C.sub.6F.sub.6 is a traditional chemistry but with aromatic C?C structure and it may be seen a 3-10 times improvement in the conductivity of the polymer as compared to molecules without the aromatic structure. C.sub.3F.sub.3N.sub.3 also has an aromatic structure and similar conductivity as C.sub.6F.sub.6. Thus, the addition of the aromatic structure in the molecules may improve the conductivity of the deposited polymer. However, C.sub.5HF.sub.4N demonstrates a significant increase in the polymer conductivity (>10,000 higher) than the other aromatic molecules.
[0223] This is a critical difference showing that the aromatic structure in the molecules alone does not lead to significant increases in polymer conductivity but specific structures, such as C.sub.5HF.sub.4N, demonstrated the significant increase in the polymer conductivity. The reason may be due to the CH bond which may as a reactive site be more able to maintain the pi* bond structure of the aromatic ring in the polymer. In addition, a silicon dopant gas was added to C.sub.4H.sub.2F.sub.6 as a comparison and as may be seen while the conductivity does increase significantly as compared to the undoped film the increase in conductivity of the polymer is significantly less than for C.sub.5HF.sub.4N.
[0224] The increase in conductivity of the polymer created by C.sub.5HF.sub.4N in the plasma is a significant improvement as compared to the molecules known in the art, similar aromatic molecules, as well as polymer doped with a silicon dopant.
Example 3
[0225] Comparison of the mass spec data of C.sub.5F.sub.5N and C.sub.5HF.sub.4N.
##STR00068##
[0226] Compared to C.sub.5F.sub.5N, C.sub.5HF.sub.4N may generate higher concentration of larger fragments, such as C.sub.4 and C.sub.5 fragments, especially hydrogen containing fragments, which may increase the degree of cross-linking of the polymer formed in the plasma phase and hence makes the polymer more electrically conductive. This property makes C.sub.5HF.sub.4N a desirable molecule to reduce the charge buildup in the high aspect ratio etch process.
Example 4
[0227] Comparison of the polymer composition of C.sub.5HF.sub.4N vs a molecule known in the art: C.sub.4F.sub.6 using a 300 mm dual CCP plasma etch chamber. Polymer was deposited on a blanket silicon wafer with a flow rate of 5 sccm of C.sub.5HF.sub.4N and 150 sccm of Ar, or 5 sccm of C.sub.4F.sub.6 and 150 sccm of Ar. The pressure was 22 mTorr, the RF source power was 950/200 W and the Bias power was 4000/200 W with a duty cycle of 70% and a Frequency of 500 Hz. The thickness of the polymer was ?50 nm for each film. Table 6 shows the composition of the polymer for each as measured using XPS.
TABLE-US-00006 TABLE 6 Gas used C % F % N % O % Other % C.sub.4F.sub.6/Ar 57 35.3 0.35 4.45 2.9 C.sub.5HF.sub.4N/Ar 60.1 22.8 7.1 6.2 3.8
[0228] As can be seen from the XPS results the polymer film deposited using C.sub.4F.sub.6 has a C:F ratio of 1.6 and for C.sub.5HF.sub.4N of 2.6. The higher C:F ratio can be beneficial for HAR etch. Also, the C.sub.5HF.sub.4N has a high concentration of nitrogen, ?7.1%. Polymer was also deposited on a blanket Si wafer using C.sub.3F.sub.3N.sub.3 and Ar or C.sub.4F.sub.8 and Ar in a similar manner on the 300 mm dual CCP plasma etch chamber. The polymer composition by XPS is shown below in Table 7.
TABLE-US-00007 TABLE 7 Gas used C % F % N % O % Other % C.sub.4F.sub.8/Ar 47.4 49.6 0 3.02 C.sub.3F.sub.3N.sub.3/Ar 53.3 16.5 14.4 13.6 2.2
[0229] As can be seen from Table 7 the C.sub.3F.sub.3N.sub.3 also gave high nitrogen composition and a higher C:F ratio than C.sub.4F.sub.8 of 3.2 vs 0.96 for C.sub.4F.sub.8. Both C.sub.3F.sub.3N.sub.3 and C.sub.5HF.sub.4N are advantageous to make high nitrogen content fluorocarbon based polymer layers using plasma.
Comparative Example 1
[0230] Polymer was deposited on a blanket silicon wafer using C.sub.3HF.sub.4N (CAS No.: 431-32-3) in a 200 mm plasma dual CCP plasma etch tool. XPS analysis of the polymer is shown in Table 8. As can be seen from this comparative data C.sub.3HF.sub.4N does not produce high nitrogen content polymer even though it contains the same number of N atoms per molecule as C.sub.5HF.sub.4N.
TABLE-US-00008 TABLE 8 Gas used C % F % N % O % Other % C.sub.3HF.sub.4N/Ar 71.8 24.8 2.5 0.9
[0231] Although the subject matter described herein may be described in the context of illustrative implementations to process one or more computing application features/operations for a computing application having user-interactive components the subject matter is not limited to these particular embodiments. Rather, the techniques described herein may be applied to any suitable type of user-interactive component execution management methods, systems, platforms, and/or apparatus.
[0232] It will be understood that many additional changes in the details, materials, steps, and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above and/or the attached drawings.
[0233] While embodiments of this invention have been shown and described, modifications thereof may be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments described herein are exemplary only and not limiting. Many variations and modifications of the composition and method are possible and within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims which follow, the scope of which shall include all equivalents of the subject matter of the claims.