USE OF COMPOSITIONS COMPRISING A SOLVENT MIXTURE FOR AVOIDING PATTERN COLLAPSE WHEN TREATING PATTERNED MATERIALS WITH LINE-SPACE DIMENSIONS OF 50 NM OR BELOW

Abstract

The invention relates to the use of a composition comprising a C.sub.1 to C.sub.6 alkanol and a carboxylic acid ester of formula (I) wherein R.sup.1 is selected from a C.sub.1 to C.sub.6 alkyl, which may be unsubstituted or substituted by OH or F, and —X.sup.21—[O—X.sup.22].sub.n—H; R.sup.2 is selected from a C.sub.1 to C.sub.6 alkyl, which may be unsubstituted or substituted by OH or F, and —X.sup.21—[O—X.sup.22].sub.n—H; X.sup.21, X.sup.22 are independently selected from C.sub.1 to C.sub.6 alkandiyl, which may be unsubstituted or substituted by OH or F; n is an integer from 1 to 5. wherein, the C.sub.1 to C.sub.6 alkanol and the carboxylic acid ester are selected so as to form an azeotropic mixture and are present in an amount from 20% by weight below to 20% by weight above such azeotropic mixture.

##STR00001##

Claims

1. A method of treating a substrate comprising a pattern having line-space dimensions of 50 nm or less and an aspect ratio of 4 or more, the method comprising contacting the substrate with a composition comprising a C.sub.1 to C.sub.6 alkanol and a carboxylic acid ester of the following formula I ##STR00004## wherein R.sup.1 and R.sup.2 are each independently selected from the group consisting of a C.sub.1 to C.sub.6 alkyl, which may be unsubstituted or substituted by OH or F, and —X.sup.21—[O—X.sup.22].sub.n—H; wherein X.sup.21 and X.sup.22 are each independently a C.sub.1 to C.sub.6 alkanediyl, which may be unsubstituted or substituted by OH or F; and n is an integer of 1 to 5, and the C.sub.1 to C.sub.6 alkanol and the carboxylic acid ester are selected so as to form an azeotropic mixture and are present in an amount of 20% by weight below to 20% by weight above the azeotropic mixture.

2. The method of claim 1, wherein the C.sub.1 to C.sub.6 alkanol and the carboxylic acid ester are selected so as to form an azeotropic mixture having a temperature minimum and are present in an amount of 10% by weight below to 10% by weight above the azeotropic mixture.

3. The method of claim 1, wherein the C.sub.1 to C.sub.6 alkanol is selected from the group consisting of methanol, ethanol, 1-propanol and 2-propanol.

4. The method of claim 1, wherein R.sup.1 is a C.sub.1 to C.sub.4 alkyl.

5. The method of claim 4, wherein R.sup.1, R.sup.2 or both R.sup.1 and R.sup.2 are selected from the group consisting of methyl, ethyl, 1-propyl and 2-propyl.

6. The method of claim 1, wherein R.sup.1, R.sup.2 or both R.sup.1 and R.sup.2 are —X.sup.21—[O—X.sup.22].sub.n—H, wherein X.sup.21 and X.sup.22 are each independently an unsubstituted C.sub.1 to C.sub.4 alkandiyl.

7. The method of claim 6, wherein X.sup.21 and X.sup.22 are each independently selected from the group consisting of methanediyl, ethanediyl, propane-1,3-diyl and propane-1,2-diyl.

8. The method of claim 1, wherein the carboxylic acid ester is selected from the group consisting of ethyl acetate and 1-methoxy-2-propylacetate.

9. The method of claim 1, wherein the C.sub.1 to C.sub.6 alkanol is 2-propanol and the carboxylic acid ester is ethyl acetate.

10. The method of claim 9, wherein the composition comprises 2-propanol in an amount of 15 to 35% by weight and ethyl acetate in an amount of 65 to 85% by weight.

11. The method of claim 1, wherein the composition consists essentially of the C.sub.1 to C.sub.6 alkanol and the carboxylic acid ester of formula I.

12. A method for manufacturing an integrated circuit device, an optical device, a micromachine and/or a mechanical precision device, the method comprising: (1) providing a substrate comprising a patterned material layer having line-space dimensions of 50 nm or less, an aspect ratio of 4 or more, or a combination thereof; (2) contacting the substrate at least once with a rinsing composition; and (3) removing the rinsing composition from the contact with the substrate, wherein the rinsing composition comprises a C.sub.1 to C.sub.6 alkanol and a carboxylic acid ester of the following formula I ##STR00005## wherein R.sup.1 and R.sup.2 are each independently selected from the group consisting of a C.sub.1 to C.sub.6 alkyl, which may be unsubstituted or substituted by OH or F, and —X.sup.21—[O—X.sup.22].sub.n—H; wherein X.sup.21 and X.sup.22 are each independently a C.sub.1 to C.sub.6 alkandiyl, which may be unsubstituted or substituted by OH or F; and n is an integer of 1 to 5.

13. The method of claim 12, wherein the patterned material layer has line-space dimensions of 32 nm or less and an aspect ratio of 4 or more.

14. The method of claim 12, wherein the patterned material layer is selected from the group consisting of a patterned developed photoresist layer, a patterned barrier material layer, a patterned multi-stack material layer and a patterned dielectric material layer.

15. The method of claim 12, wherein the substrate is provided by a photolithographic process comprising: (i) providing a substrate with an immersion photoresist, EUV photoresist or eBeam photoresist layer; (ii) exposing the photoresist layer to actinic radiation through a mask with or without an immersion liquid, to obtain an exposed photoresist layer; and (iii) developing the exposed photoresist layer with a developer solution, to obtain a pattern having line-space dimensions of 50 nm or less and an aspect ratio of 4 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention is directed to a composition particularly suitable for manufacturing patterned materials comprising sub 50 nm sized features like integrated circuit (IC) devices, optical devices, micromachines and mechanical precision devices, in particular IC devices.

[0031] Any customary and known substrates used for manufacturing IC devices, optical devices, micromachines and mechanical precision devices can be used in the process of the invention. Preferably, the substrate is a semiconductor substrate, more preferably a silicon wafer, which wafers are customarily used for manufacturing IC devices, in particular IC devices comprising ICs having LSI, VLSI and ULSI.

[0032] The composition is particularly suitable for treating substrates having patterned material layers having line-space dimensions of 50 nm and less, in particular, 32 nm and less and, especially, 22 nm and less, i.e. patterned material layers for the sub-22 nm technology nodes. The patterned material layers preferably have aspect ratios above 4, preferably above 5, more preferably above 6, even more preferably above 8, even more preferably above 10, even more preferably above 12, even more preferably above 15, even more preferably above 20. The smaller the line-space dimensions and the higher the aspect ratios are the more advantageous is the use of the composition described herein. The critical aspect ratio also depends on the substrate to be treated for anti pattern collapse. For example, since low-k dielectrics are more unstable and tend to collapse aspect ratios of 4 are already challenging.

[0033] The composition according to the present invention may be applied to substrates of any patterned material as long as structures tend to collapse due to their geometry.

[0034] By way of example, the patterned material layers may be [0035] (a) patterned silicon layers or silicon oxide or silicon nitride coated Si layers, [0036] (b) patterned barrier material layers containing or consisting of ruthenium, cobalt, titanium nitride, tantalum or tantalum nitride, [0037] (c) patterned multi-stack material layers containing or consisting of layers of at least two different materials selected from the group consisting of silicon, polysilicon, silicon dioxide, low-k and ultra-low-k materials, high-k materials, semiconductors other than silicon and polysilicon, and metals, and [0038] d) patterned dielectric material layers containing or consisting of silicon dioxide or low-k or ultra-low-k dielectric materials.

[0039] The composition comprises two types or organic solvents, a C.sub.1 to C.sub.6 alkanol and a carboxylic acid ester.

Alkanol

[0040] The first organic solvent of the composition is a linear or branched C.sub.1 to C.sub.6 alkanol (also referred to as “alkanol”).

[0041] Preferably the alkanol is a C.sub.1 to C.sub.5 alkanol, more preferably a C.sub.1 to C.sub.4 alkanol, most preferably methanol, ethanol, 1-propanol or 2-propanol. Particularly preferred is 2-propanol.

Ester

[0042] The second organic solvent of the composition is a carboxylic acid ester of formula I (also referred to as “ester”):

##STR00003##

wherein [0043] R.sup.1 is selected from a linear or branched C.sub.1 to C.sub.6 alkyl, which may be unsubstituted or substituted by OH or F, and —X.sup.21—[O—X.sup.22].sub.n—H; [0044] R.sup.2 is selected from a linear or branched C.sub.1 to C.sub.6 alkyl, which may be unsubstituted or substituted by OH or F, and —X.sup.21—[O—X.sup.22].sub.n—H; [0045] X.sup.21, X.sup.22 are independently selected from a linear or branched C.sub.1 to C.sub.6 alkandiyl, which may be unsubstituted or substituted by OH or F; [0046] n is an integer from 1 to 5.

[0047] In a first preferred embodiment R.sup.1 is selected from a linear or branched C.sub.1 to C.sub.5 alkyl, more preferably C.sub.1 to C.sub.4 alkyl, most preferably methyl, ethyl, 1-propyl or 2-propyl. Such alkyl which may be unsubstituted or substituted by OH or F. R.sup.2 is selected from a linear or branched C.sub.1 to C.sub.5 alkyl, more preferably C.sub.1 to C.sub.4 alkyl, most preferably methyl, ethyl, 1-propyl or 2-propyl. Such alkyl which may be unsubstituted or substituted by OH or F.

[0048] In a second preferred embodiment R.sup.1 is selected from a linear or branched C.sub.1 to C.sub.5 alkyl, more preferably C.sub.1 to C.sub.4 alkyl, most preferably methyl, ethyl, 1-propyl or 2-propyl. Such alkyl which may be unsubstituted or substituted by OH or F. R.sup.2 is —X.sup.21—[O—X.sup.22].sub.n—H, wherein X.sup.21, X.sup.22 are independently selected from a linear or branched C.sub.1 to C.sub.6 alkandiyl, preferably C.sub.1 to C.sub.5 alkandiyl, more preferably C.sub.1 to C.sub.4 alkandiyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl or propane-1,2-diyl; and is an integer from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, even more preferably 1 or 2, most preferably 1. Such alkanediyl may be unsubstituted or substituted by OH or F.

[0049] In a third preferred embodiment R.sup.1 is —X.sup.21[O—X.sup.22].sub.n—H, wherein X.sup.21, X.sup.22 are independently selected from a linear or branched C.sub.1 to C.sub.6 alkandiyl, preferably C.sub.1 to C.sub.5 alkandiyl, more preferably C.sub.1 to C.sub.4 alkandiyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl or propane-1,2-diyl; and is an integer from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, even more preferably 1 or 2, most preferably 1. Such alkanediyl may be unsubstituted or substituted by OH or F. R.sup.2 is selected from a linear or branched C.sub.1 to C.sub.5 alkyl, more preferably C.sub.1 to C.sub.4 alkyl, most preferably methyl, ethyl, 1-propyl or 2-propyl.

[0050] In a forth preferred embodiment R.sup.1 is —X.sup.21—[O—X.sup.22].sub.n—H, wherein X.sup.21, X.sup.22 are independently selected from a linear or branched C.sub.1 to C.sub.6 alkandiyl, preferably C.sub.1 to C.sub.5 alkandiyl, more preferably C.sub.1 to C.sub.4 alkandiyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl or propane-1,2-diyl; and is an integer from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, even more preferably 1 or 2, most preferably 1. Such alkanediyl may be unsubstituted or substituted by OH or F. R.sup.2 is —X.sup.21—[O—X.sup.22].sub.n—H, wherein X.sup.21, X.sup.22 are independently selected from a linear or branched C.sub.1 to C.sub.6 alkandiyl, preferably C.sub.1 to C.sub.5 alkandiyl, more preferably C.sub.1 to C.sub.4 alkandiyl, most preferably methanediyl, ethanediyl, propane-1,3-diyl or propane-1,2-diyl; and is an integer from 1 to 5, preferably from 1 to 4, more preferably from 1 to 3, even more preferably 1 or 2, most preferably 1. Such alkanediyl may be unsubstituted or substituted by OH or F.

[0051] Particularly preferred esters are ethyl acetate, methyl acetate, isopropyl acetate and 1-methoxy-2-propyl acetate, also known as propylene glycol monomethylether acetate or PGMEA.

Composition

[0052] The alkanol and the ester need to be capable of forming an azeotropic mixture, preferably an azeotropic mixture showing a temperature minimum. Generally, the content of the alkanol in the solvent mixture of the alkanol and the ester preferably is from 20% by weight below to 20% by weight above the azeotropic mixture.

[0053] In a preferred embodiment, the content of the alkanol in the solvent mixture of the alkanol and the ester preferably is from 15% by weight below to 15% by weight above the azeotropic mixture. More preferably the content of the alkanol in the solvent mixture of the alkanol and the ester preferably is from 10% by weight below to 10% by weight above the azeotropic mixture. Even more preferred the content of the alkanol in the solvent mixture of the alkanol and the ester preferably is from 8% by weight below to 8% by weight above the azeotropic mixture. Most preferably the content of the alkanol in the solvent mixture of the alkanol and the ester preferably is from 5% by weight below to 5% by weight above the azeotropic mixture.

[0054] In a particularly preferred embodiment the anti pattern collapse cleaning (APCC) composition essentially consists of organic solvents, particularly it essentially consists of the alkanol and the carboxylic acid ester.

[0055] In another embodiment the composition is a homogeneous (one phase) composition.

[0056] If a combination of 2-propanol and ethyl acetate is used the 2-propanol is preferably present in an amount of from 15 to 35% by weight, particularly from 20 to 30% by weight.

[0057] Preferably the composition is non-aqueous. As used herein, “non-aqueous” means that the composition may only contain low amounts of water up to about 1% by weight. Preferably the non-aqueous composition comprises less than 0.5% by weight, more preferably less than 0.2% by weight, even more preferably less than 0.1% by weight, even more preferably less than 0.05% by weight, even more preferably less than 0.02% by weight, even more preferably less than 0.01% by weight, even more preferably less than 0.001% by weight. Most preferably essentially no water is present in the composition. “Essentially” here means that the water present in the composition does not have a significant influence on the performance of the additive in the non-aqueous composition with respect to pattern collapse of the substrates to be treated.

[0058] Furthermore, it was surprisingly found that in contrast to the use of a single organic solvent and a siloxane-type additive as described in European patent application No. 17199807.3 the composition according to the present invention is highly tolerable with respect to its water content. Therefore, the composition may contain up to 10% by volume of water and a pre-drying of the solvents can be avoided. Preferably the water content may be from 0.5 to 5% by weight.

[0059] The solvent mixture should have a boiling point sufficiently low to be removed by heating without negatively impacting the substrate treated with the composition. For typical substrates, the boiling point of the organic solvent should be 150° C. or below, preferably 100° C. or below.

[0060] Besides the two organic solvents other organic solvents may be present in amounts up to 10% by weight.

[0061] Further additives like surfactants may be present in the compositions in an amount to support the anti pattern collapse characteristics of the composition. Such surfactants may be, but are not limited to those of formulae I to IV in unpublished European patent application No. 17199807.3, which are explicitly incorporated herein by reference.

[0062] The content of other compounds should preferably be below 1% by weight, more preferably below 0.5% by weight, even more preferably below 0.1% by weight, most preferably below 0.01% by weight. It is particularly preferred that the compositions, essentially consist of the two organic solvents present in the compositions according to the present invention. As used herein, “Essentially consisting of” means that the content of other components does not influence the anti pattern collapse characteristics of the composition.

[0063] In accordance with the method of the invention, the composition comprising the alkanol and the ester may be used for different purposes and objects. Thus, it may be used as an immersion liquid for immersing photoresists during irradiation with actinic light through a mask, as a developer solution for photoresist layers exposed to actinic radiation through a mask and as a chemical rinse composition for rinsing the patterned material layers.

[0064] In one embodiment, the method for manufacturing integrated circuit devices, optical devices, micromachines and mechanical precision devices has been found, the method comprising the steps of [0065] (1) providing a substrate having patterned material layers having line-space dimensions of 50 nm and less and aspect ratios of greater or equal 4, [0066] (2) contacting the substrate at least once with a composition comprising the alkanol and the ester as described herein, [0067] and [0068] (3) removing the composition from the contact with the substrate.

[0069] In the third step of the method according to the invention, composition is removed from the contact with the substrate. Any known methods customarily used for removing liquids from solid surfaces can be employed.

[0070] Preferably the substrate is provided by a photolithographic process comprising the steps of [0071] (i) providing the substrate with an immersion photoresist, EUV photoresist or eBeam photoresist layer, [0072] (ii) exposing the photoresist layer to actinic radiation through a mask with or without an immersion liquid, [0073] (iii) developing the exposed photoresist layer with a developer solution to obtain a pattern having line-space dimensions of 32 nm and less and an aspect ratio of 4 or more, [0074] (iv) applying the composition described herein to the developed patterned photoresist layer, and [0075] (v) spin drying the semiconductor substrate after the application of the composition.

[0076] Any customary and known immersion photoresist, EUV photoresist or eBeam photoresist can be used. The immersion photoresist may already contain at least one of the siloxane additives or a combination thereof. Additionally, the immersion photoresist may contain other nonionic additives. Suitable nonionic additives are described, for example, in US 2008/0299487 A1, page 6, paragraph [0078]. Most preferably, the immersion photoresist is a positive resist.

[0077] Beside e-Beam exposure or extreme ultraviolet radiation of approx. 13.5 nm, preferably, UV radiation of the wavelength of 193 nm is used as the actinic radiation.

[0078] In case of immersion lithography preferably, ultra-pure water is used as the immersion liquid.

[0079] Any customary and known developer solution can be used for developing the exposed photoresist layer. Preferably, aqueous developer solutions containing tetramethylammonium hydroxide (TMAH) are used.

[0080] Preferably, the chemical rinse compositions are applied to the exposed and developed photoresist layers as puddles.

[0081] It is essential for photolithographic process according to the method of the invention, that the chemical rinse composition contains the alcohol and the ester in combination.

[0082] Customary and known equipment customarily used in the semiconductor industry can be used for carrying out the photolithographic process in accordance with the method of the invention.

Examples

[0083] Patterned silicon wafers with a circular nano pillar pattern were used to determine the pattern collapse performance of the formulations during drying. The (aspect ratio) AR 20 pillars used for testing had a height of 600 nm and a diameter of 30 nm. The pitch size was 90 nm. 1×1 cm wafer pieces where processed in the following sequence without drying in between: [0084] 50 s Dilute Hydrofluoric Acid (DHF) 0.9% dip, [0085] 60 s ultra-pure water (UPW) dip, [0086] 30 s 2-propanol (isopropanol, IPA) dip, [0087] 60 s dip with a composition consisting 2-propanol in an amount specified in table 1 and ethyl acetate at room temperature, [0088] 60 s IPA dip, [0089] N.sub.2 blow dry.

[0090] The dried silicon wafers where analyzed with top down SEM and the collapse statistics for the examples are shown in Tables 1 to 4. Since the collapse varies from center to edge only structures taken from essentially the same center edge distance were compared.

[0091] The pattern collapse Cluster Size Distribution was determined from the SEM images. The cluster size corresponds to number of uncollapsed pillars the respective cluster consist of. By way of example, if the wafer before treatment comprises 4×4 pillars and 8 remain uncollapsed, 4 collapsed into two clusters comprising 2 pillars and 4 pillars collapse into one cluster comprising 4 pillars the ratio would be 8/11 single clusters, 2/11 double clusters and 1/11 clusters with four pillars. The more single (1) clusters are present, the better is the performance of the anti pattern collapse treatment. The more 3 or 4 or even >5 clusters are present the worse is the effect of treatment.

TABLE-US-00001 TABLE 1 Cluster Size Distribution in 2-propanol collapsed structures [%] Example [mass %] 1 2 3 or 4 >5 1 (comp.) 100 46.2 20.8 32.8 0.3 3 30 99.1 0.9 0.0 0.0 4 25 99.9 0.1 0.0 0.0 5 20 99.4 0.6 0.0 0.0 6 15 69.6 3.7 36.2 0.5

[0092] Table 1 shows that compositions 3 to 6 show a beneficial effect on the degree of pattern collapse compared to the composition with 2-propanol only. Particularly the compositions close to the azeotropic mixture with 20 to 30% by weight of 2-propanol and 70 to 80% by weight of ethyl acetate show essentially no collapse at all.

TABLE-US-00002 TABLE 2 Cluster Size Distribution in 2-propanol collapsed structures [%] Example [mass %] 1 2 3 or 4 >5 7 (comp.) 100 62.1 12.8 24.8 0.3 8 (comp) 0 42.2 8.1 49.2 0.5 9 25 100.0 0.0 0.0 0.0

[0093] The results of experiments 7 to 8 depicted in Table 2 show that the combination of the claimed solvents show a dramatic effect on the anti pattern collapse compared to the singles solvents.

TABLE-US-00003 TABLE 3 Cluster Size Distribution in 2-propanol collapsed structures [%] Example [mass %] 1 2 3 or 4 >5 10 (comp.) 100  32.5 20.2 47.0 0.3 11 (comp) 90* 26.7 17.6 55.4 0.3 12 25* 99.9 0.1 0.0 0.0 *azeotropic mixture is approx. 25% by weight of 2-propanol

[0094] The results of experiments 10 to 12 depicted in Table 3 show that high amounts of 2-propanol have no positive effect on the anti pattern collapse treatment in contrast to the claimed amounts.

TABLE-US-00004 TABLE 4 Cluster Size Distribution in H2O 2-propanol collapsed structures [%] Example [mass %] [mass %] 1 2 3 or 4 >5 13 (comp.) 100 32.5 20.2 47.0 0.3 14 25 99.9 0.05 0.05 0.0 15 0.1 24.95 99.9 0.05 0.05 0.0 16 1 24.5 99.9 0.05 0.05 0.0 17 10 20 99.8 0.2 0.0 0.0

[0095] The results of experiments 13 to 17 depicted in Table 4 show that surprisingly, and in contrast to the use of a single solvent in combination with additives like the siloxane-type surfactants described in unpublished European Patent Application No. 17199807.3, the solvent mixture is ex-tremely tolerant with respect to its content of water. Even an amount of 10% of water shows only a minor effect on the anti pattern collapse performance of the composition. Extensive drying of the solvents can be omitted in this way.