Coating composition for the production of insulating thin films

• US 20030099844A1
• Filed: 10/04/2002
• Published: 05/29/2003
• Est. Priority Date: 04/04/2000
• Status: Active Grant

• Current Assignee: Asahi Kasei Kabushiki Kaisha (Asahi Kasei Corporation)
• Original Assignee: Asahi Kasei Kabushiki Kaisha (Asahi Kasei Corporation)
• Inventors: Nakamura, Mikihiko, Araki, Toru, Hanahata, Hiroyuki
• Granted Patent: US 6,787,191 B2
• Time in Patent Office: Days
• US Class Current: 428/447
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: C09D 183/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C09D183/10 takes precedence
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02282 liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/3121 Layers comprising organo-silicon compounds
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 21/316 composed of oxides or glassy oxides or oxide based glass
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Disclosed is a coating composition for use in producing an insulating thin film, comprising:

(A) at least one silica precursor comprised of at least one compound selected from the group consisting of an alkoxysilane and a hydrolysis product thereof;

(B) at least one organic polymer;

(C) water;

(D) at least one alcohol; and optionally

(E) an organic solvent for a mixture of the components (A), (B), (C) and (D);

wherein the weight ratio (WR) of the water (C) to the at least one silica precursor (A) satisfies the formula 0.01<WR<10, and the weight of the water (C) is larger than that of the at least one alcohol (D),

with the proviso that when the at least one organic polymer (B) is insoluble in a mixture of the water (C) and the alcohol (D), the coating composition comprises all of the components (A) to (E).

Claims

1. A coating composition for use in producing an insulating thin film, comprising:

(A) at least one silica precursor selected from the group consisting of the following silica precursors (A-1) and (A-2);

a silica precursor (A-1) comprised of at least one compound selected from the group consisting of an alkoxysilane represented by the following formula (1) and a hydrolysis product thereof;

R¹_nSi(OR²)<sub>4−

n</sub>  

 

(1)

wherein each R¹ independently represents a hydrogen atom, a straight chain or branched alkyl group having 1 to 6 carbon atoms, a vinyl group or a phenyl group, each R² independently represents a straight chain or branched alkyl group having 1 to 6 carbon atoms and n represents an integer of from 0 to 3; and

a silica precursor (A-2) comprised of at least one compound selected from the group consisting of an alkoxysilane represented by the following formula (2) and a hydrolysis product thereof;

R³_m(R⁴O)<sub>3−

m</sub>Si—

(R⁷)_p—

Si(OR⁵)<sub>3−

q</sub>R⁶_q  

 

(2)

wherein each R³ independently represents a hydrogen atom, a straight chain or branched alkyl group having 1 to 6 carbon atoms, a vinyl group or a phenyl group, each R⁴ independently represents a straight chain or branched alkyl group having 1 to 6 carbon atoms, each R⁵ independently represents a straight chain or branched alkyl group having 1 to 6 carbon atoms, each R⁶ independently represents a hydrogen atom, a straight chain or branched alkyl group having 1 to 6 carbon atoms, a vinyl group or a phenyl group, R⁷ represents an oxygen atom, a phenylene group or a group represented by the formula;

—

(CH₂)_r—

wherein r represents an integer of from 1 to 6, each of m and q independently represents an integer of from 0 to 2, and p represents 0 or 1;

(B) at least one organic polymer;

(C) water;

(D) at least one alcohol; and

optionally

(E) an organic solvent for a mixture of said components (A), (B), (C) and (D);

wherein the weight ratio (WR) of said water (C) to said at least one silica precursor (A) satisfies the formula 0.01<

WR<

10, and the weight of said water (C) is larger than that of said at least one alcohol (D),

with the proviso that when said at least one organic polymer (B) is insoluble in a mixture of said water (C) and said alcohol (D), said coating composition comprises all of said components (A) to (E).

2. The composition according to claim 1, wherein the weight ratio (WR) satisfies the formula 0.1<

WR<

10.

3. The composition according to claim 1 or 2, wherein the weight ratio of said water (C) to said alcohol (D) is 5 or less.

4. The composition according to any one of claims 1 to 3, wherein said organic polymer (B) is selected from the group consisting of:

(B-1) an organic polymer having at least one polymerizable functional group in a molecule thereof; and

(B-2) an organic polymer having at least one terminal group which is inert to said silica precursor (A).

5. The composition according to claim 4, wherein said terminal group of said organic polymer (B-2) is an alkyl ether group.

6. The composition according to any one of claims 1 to 5, wherein said organic polymer (B) has a number average molecular weight of from 200 to 1,000,000.

7. The composition according to any one of claims 1 to 6, wherein said organic polymer (B) is present in an amount of from 0.01 to 10 parts by weight, relative to 1 part by weight of a product obtained by gelation of the whole amount of said silica precursor (A).

8. The composition according to any one of claims 1 to 7, which further comprises phosphoric acid.

9. The composition according to any one of claims 1 to 8, wherein said silica precursor (A) has at least one Si—

O—

P—

linkage.

10. A silica/organic polymer composite thin film, which is produced by a process comprising:

coating the composition of any one of claims 1 to 9 on a substrate to form a thin film of the composition on the substrate, and

subjecting said thin film to gelation with respect to said silica precursor (A) to thereby obtain a silica/organic polymer composite thin film.

11. A porous silica thin film which is obtained by removing said organic polymer (B) from the silica/organic polymer composite thin film of claim 10.

12. A multilevel interconnect comprising a plurality of insulating layers and circuits formed on said insulating layers, wherein at least one layer of said insulating layers comprises the thin film of claim 10 or 11.

13. A semiconductor device comprising the multilevel interconnect of claim 12.

14. A method for producing a porous silica thin film, which comprises the steps of:

(1) coating the composition of any one of claims 1 to 9 on a substrate to form a thin film of the composition on the substrate,

(2) heating said thin film at a temperature T₁ satisfying the formula 60°

C.≦

T₁≦

Ta in an atmosphere of inert gas having an oxygen concentration of not higher than 5% by volume, wherein Ta represents the temperature at which a 1% by weight decrease in weight of said at least one organic polymer (B) is reached when said at least one organic polymer (B) is heated at a temperature elevation rate of 10°

C./min in an atmosphere of inert gas, wherein the inert gas is fed at a feeding rate of 40 ml/min, to thereby effect gelation of said silica precursor (A) and obtain a silica/organic polymer composite thin film, and

(3) heating said composite thin film at a temperature T₂ satisfying the formula Ta≦

T₂≦

450°

C., wherein Ta is as defined above, in an atmosphere of inert gas having an oxygen concentration of not higher than 5% by volume, to thereby remove said organic polymer (B) from said composite thin film.