Composition for metal electroplating comprising leveling agent

Abstract

A composition comprising a source of metal ions and at least one additive comprising at least one polyaminoamide, said polyaminoamide comprising the structural unit represented by formula I ##STR00001##
or derivatives of the polyaminoamide of formula I obtainable by complete or partial protonation, N-functionalization or N-quaternization with a non-aromatic reactant,
wherein D.sup.6 is, for each repeating unit 1 to s independently, a divalent group selected from a saturated or unsaturated C.sub.1-C.sub.20 organic radical, D.sup.7 is, for each repeating unit 1 to s independently, a divalent group selected from straight chain or branched C.sub.2-C.sub.20 alkanediyl, which may optionally be interrupted by heteroatoms or divalent groups selected from O, S and NR.sup.10, R.sup.1 is, for each repeating unit 1 to s independently, selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, or, together with R.sup.2, may form a divalent group D.sup.8, and R.sup.2 is, for each repeating unit 1 to s independently, selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, or, together with R.sup.1, may form a divalent group D.sup.8, and D.sup.8 is selected from straight chain or branched C.sub.1-C.sub.18 alkanediyl, which may optionally be interrupted by heteroatoms or divalent groups selected from O, S and NR.sup.10, s is an integer from 1 to 250, R.sup.10 is selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl.

Claims

1. A composition, comprising: a source of metal ions, at least one additive comprising at least one polyaminoamide comprising a structural unit represented by the formula I: ##STR00014## or a derivative of the polyaminoamide of the formula I obtained by complete or partial protonation, N-functionalization or N-quaternization with a non-aromatic reactant, wherein D.sup.6 is selected from a straight chain or branched, acyclic or cyclic C.sub.1-C.sub.20 alkanediyl, wherein D.sup.6 is the same or different when s is more than 1, D.sup.7 is a divalent group selected from straight chain or branched C.sub.2-C.sub.20 alkanediyl, which may optionally be interrupted by heteroatoms or divalent groups selected from O, S and NR.sup.10, wherein D.sup.7 is the same or different when s is more than 1, R.sup.1 is selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, or, together with R.sup.2, may form a divalent group D.sup.8, wherein R.sup.1 is the same or different when s is more than 1, R.sup.2 is selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, or, together with R.sup.1 , may form a divalent group D.sup.8, wherein R.sup.2 is the same or different when s is more than 1, D.sup.8 is selected from straight chain or branched C.sub.1-C.sub.18 alkanediyl, which may optionally be interrupted by heteroatoms or divalent groups selected from O, S and NR.sup.10, s is an integer from 1 to 250, and R.sup.10 is selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl, and an accelerating agent.

2. The composition according to claim 1, wherein the polyaminoamide is represented by the formula IV: ##STR00015## wherein E.sup.3, E.sup.4 are independently selected from the group consisting of: (a) NH—C.sub.1-C.sub.20-alkyl or NH—C.sub.1-C.sub.20-alkenyl, (b) N—(C.sub.1-C.sub.20-alkyl).sub.2 or N—(C.sub.1-C.sub.20-alkenyl).sub.2 or N—(C.sub.1-C.sub.20-alkyl)(C.sub.1-C.sub.20-alkenyl) (c) NR.sup.2-D.sup.7-NR.sup.2H, and (d) NR.sup.2-D.sup.7-NR.sup.2—CH.sub.2—CH.sub.2—CO—NH—(C.sub.1-C.sub.20-alkyl) or NR.sup.2-D.sup.7-NR.sup.2—CH.sub.2—CH.sub.2—CO—NH—(C.sub.1-C.sub.20-alkenyl).

3. The composition according to claim 2, wherein E.sup.3 and E.sup.4 are independently defined as NR.sup.1-D.sup.7-NR.sup.2H.

4. The composition according to claim 1, wherein the metal ions comprise copper ion.

5. The composition according to claim 1, wherein: D.sup.6 is (CH.sub.2).sub.g, and g is an integer from 1 to 6.

6. The composition according to claim 1, wherein D.sup.7 is a straight chain C.sub.2- to C.sub.6-alkanediyl.

7. The composition according to claim 1, wherein s is an integer from 1 to 150.

8. The composition according to claim 1, wherein R.sup.1 is selected from the group consisting of H, C.sub.1-C.sub.20-alkyl, and C.sub.1-C.sub.20-alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl.

9. The composition according to claim 1, wherein R.sup.2 is selected from the group consisting of H, C.sub.1-C.sub.20-alkyl, and C.sub.1-C.sub.20-alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl.

10. The composition according to claim 1, wherein R.sup.1 and R.sup.2 together form a divalent group D.sup.8, with D.sup.8 being a straight chain or branched C.sub.1-C.sub.18 alkanediyl, which may optionally be interrupted by at least one heteroatom or divalent group selected from the group consisting of O, S and NR.sup.10, with R.sup.10 being selected from H, C.sub.1-C.sub.20 alkyl, and C.sub.1-C.sub.20 alkenyl, which may optionally be substituted by hydroxyl, alkoxy or alkoxycarbonyl.

11. The composition according to claim 1, further comprising a suppressing agent.

12. The composition according to claim 1, wherein s is an integer from 2 to 100.

13. The composition according to claim 1, wherein s is an integer from 2 to 50.

14. A process for depositing a metal layer on a substrate, the process comprising: a) contacting a metal plating bath comprising the composition according to claim 1 with a substrate; and b) applying a current density to the substrate for a time sufficient to deposit a metal layer onto the substrate.

15. The process according to claim 14, wherein the substrate comprises micrometer or nanometer sized features and the deposition is performed to fill the micrometer or nanometer sized features.

16. The process according to claim 15, wherein the nanometer-sized features have a size from 1 to 1000 nm, an aspect ratio of 4 or more, or both.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1a schematically shows a dielectric substrate 1 seeded with a copper layer 2a.

(2) FIG. 1b schematically shows a copper layer 2′ deposited onto the dielectric substrate 1 by electrodeposition.

(3) FIG. 1c schematically shows the removed overburden of copper 2b by chemical mechanical planarization (CMP).

(4) FIG. 2a schematically shows the result of an electrodeposition without using a leveling agent.

(5) FIG. 2b schematically shows the result of an electrodeposition by using a leveling agent.

(6) FIG. 3a shows a profilometry cross-sectional scan of nested trenches having 0.130 micrometer width with a separation of 0.130 micrometer without a leveler according to comparative example 2.

(7) FIG. 3b shows a profilometry cross-sectional scan of 0.250 micrometer features without a leveler according to comparative example 2.

(8) FIG. 4a shows a profilometry cross-sectional scan of nested trenches having 0.130 micrometer width with a separation of 0.130 micrometer with a leveler according to example 3.

(9) FIG. 4b shows a profilometry cross-sectional scan of 0.250 micrometer features with a leveler according to example 3.

(10) The following examples shall further illustrate the present invention without restricting the scope of this invention.

EXAMPLES

(11) The amine number was determined according to DIN 53176 by titration of a solution of the polymer in acetic acid with perchloric acid.

(12) The acid number was determined according to DIN 53402 by titration of a solution of the polymer in water with aqueous sodium hydroxide solution.

(13) The molecular weight (Mw) was determined by size exclusion chromatography using hexafluoroisopropanol containing 0.05% potassium trifluoroacetate as eluent, hexafluoroisopropanol-packed (HFIP) gel columns as stationary phase and polymethylmethacrylate (PMMA) standards for determination of the molecular weights.

Example 1

Polyaminoamide from Piperazine and Methylene Bisacrylamide (Molecular Ratio 19:18)

(14) ##STR00013##

(15) A 500 ml apparatus flushed with nitrogen was charged with methylene bisacrylamide (50.0 g, 324 mmol), water (150 g) and butylated hydroxyanisole (150 mg, 0.8 mmol). The resulting mixture was stirred vigorously (900 rpm). The reaction flask was protected from light by wrapping the apparatus with aluminum foil. The mixture was cooled to 0° C. and piperazine (29.5 g, 342 mmol) was added in portions during 30 min. After the complete addition of piperazine the resulting mixture was stirred additional 60 min at 0° C. Then, the cooling bath was removed and the reaction mixture was stirred at ambient temperature for 48 h at 500 rpm. The crude reaction mixture was concentrated under reduced pressure to give the title compound as light pink solid.

(16) The resulting polyaminoamide showed an amine number of 2.95 mmol/g. Gel permeation chromatography revealed an average molecular weight of M.sub.w=37400 g/mol and a polydispersity of M.sub.w/M.sub.n=1.7.

Comparative Example 2

(17) A copper plating bath was prepared by combining 40 g/l copper as copper sulfate, 10 g/l sulfuric acid, 0.050 g/l chloride ion as HCl, 0.100 g/l of an EO/PO copolymer suppressor, and 0.028 g/l of SPS and DI water. The EO/PO copolymer suppressor had a molecular weight M.sub.w of below 5000 g/mol and terminal hydroxyl groups.

(18) A copper layer was electroplated onto a structured silicon wafer purchased from SKW Associate Inc. containing grooves, so called trenches. These lines varied in width ranging from 130 nm to several micrometers with a depth of approximately 250 nm and a separation ranging from 130 nm to several micrometers. Such wafer substrates were brought into contact with the above described plating bath at 25 degrees C. and a direct current of −5 mA/cm.sup.2 for 120 s followed by −10 mA/cm.sup.2 for 60 s was applied.

(19) The thus electroplated copper layer was investigated by profilometry inspection with a Dektak 3, Veeco Instruments Inc. The 130 nm and 250 nm feature sizes a field of nested wires was scanned and the height difference between the unstructured and structured area was measured.

(20) The results without using a leveling agent are shown in FIGS. 3a and 3b and show a profilometry cross-sectional scan of nested trenches having 0.130 micrometer width with a separation of 0.130 micrometer (FIG. 3a) and a cross-sectional scan of 0.250 micrometer features (FIG. 3b), respectively. Both, FIGS. 3a and 3b show a higher copper deposition rate on the structured area (a) in relation to the unstructured area (b). This phenomenon is well known as mounding and is strongly pronounced over the 0.130 and 0.250 micrometer trenches. The measured values are depicted in table 1.

Example 3

(21) The procedure of comparative example 2 was repeated except that 1 ml/l of a 1% by weight aqueous solution of the polymer from example 1 was added to the plating bath.

(22) A copper layer was electroplated onto a wafer substrate as described in comparative example 2. The thus electroplated copper layer was investigated by profilometry as described in comparative example 2.

(23) The results using a plating bath with a leveling agent according to the present invention are shown in FIGS. 4a and 4b for different trench sizes. The profilometry cross-sectional scan of nested trenches having 0.130 micrometer width with a separation of 0.130 μm (FIG. 4a), respectively a cross-sectional scan of 0.250 μm features (FIG. 4b) show a significant reduction of the mounding compared to the prior art. The measured values are depicted in table 1.

(24) TABLE-US-00001 TABLE 1 Feature size 0.130 micrometer 0.250 micrometer example 2 (prior art) +570 nm +265 nm example 3  −5 nm  −22 nm