JPH021778A - Coating liquid for forming oxide coating film and production of oxide coating film - Google Patents

Abstract

PURPOSE:To provide the subject coating liquid containing a reaction product produced by the hydrolysis and condensation of a specific silane compound and a specific metal alkoxide compound, having high thermal stability and good film-forming property and useful for the coating of an interlayer step in a multilayer wiring of semiconductor. CONSTITUTION:The objective coating liquid contains a reaction product produced by the hydrolysis and condensation of (A) a silane compound of formula RmSi(OR)4-m (R is 1-4C alkyl or aryl; m is 0-2) [e.g., Si(OCH3)4] and (B) a metal alkoxide compound of formula M(OR')n (M is Mg, B, P, Zr, Y, Ti or Ba; R' is 1-4C alkyl or aryl; n is atomic valence of M) [e.g., B(O-iC3H7)3] in a solvent in the presence of a catalyst (e.g., hydrochloric acid or oxalic acid).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a coating solution for forming an oxide film and a method for producing an oxide film, and more specifically to a coating solution for forming an oxide film and a method for producing an oxide film that is thermally stable and has good film formability. The present invention relates to a method for producing an oxide film and a coating liquid for forming the oxide film.

(Prior art) Conventionally, as a method for glabellar insulation of semiconductor devices such as ICs and LSIs, a hydrolysis/condensation product of a silanol compound is fired.
Methods of forming oxide films are well known. The most studied method is to use tetrafunctional silanes such as tetraethoxysilane (ethyl silicate), but in the method using only tetrafunctional silanes, the three-dimensional cross-linked structure is extremely difficult to form when firing to form a silica film. Since the film becomes dense and rigid, it has the disadvantage that cracks occur as the film becomes thicker. In order to improve this drawback, methods of co-hydrolyzing bifunctional and trifunctional silanes are shown in Japanese Patent Application Laid-open No. 191219/1983, but these methods do not contain a large amount of carbon in the condensate or film. is included, and if carbon remains in the film after firing, there is a drawback that cracks will occur in the subsequent semiconductor manufacturing process. In addition, in order to desorb carbon contained in the film, K requires a high temperature of 500°C or higher, and the film shrinks due to desorption of carbon or the heat generated between the desorbed film and the substrate such as silicon or aluminum. Due to the large difference in expansion coefficient,
There is a drawback that cracks occur in the film.

(Problem to be solved by the invention) The object of the present invention is to eliminate the drawbacks of the prior art.

The object of the present invention is to provide a method for producing an oxide film that is thermally stable and has good film formability, and a coating liquid for forming the oxide.

(Means for Solving the Problems) As a result of various studies to achieve the above object, the present inventors have found that no cracks occur on substrates such as silicon and aluminum, and even with subsequent oxygen 7° plasma treatment. In order to form a crack-free oxide film, (1) reduce the curing shrinkage strain during firing; (2) Bringing the coefficient of thermal expansion of the membrane close to that of the substrate.

(3) It is necessary to use a coating solution that satisfies the condition of extremely reducing or eliminating the carbon content in the film, and the coating solution is made by applying a specific compound in the presence of a solvent using a catalyst. The present invention was achieved by discovering that it can be obtained by hydrolysis and condensation.

The present invention is a general prisoner 2 Rm Sr (OR) 4-m (
During the ceremony.

几 is an alkyl group or an alkyl group having 1 to 4 carbon atoms.

mit, meaning an integer from 0 to 2), and (B) a silane compound represented by the general formula M(OR')n (wherein 9M is a metal of magnesium, boron, phosphorus, zirconium, yttrium, titanium, or barium); Atom, R' has 1 or more carbon atoms
A reaction product obtained by hydrolyzing and condensing a metal alkoxide compound represented by the alkyl group or aryl group of 4 (n means the valence of the metal atom M) using a catalyst in the presence of a solvent. The present invention relates to a coating liquid for forming an oxide film comprising the coating liquid and a method for producing the coating liquid.

The silane compound used in the present invention has the general formula Rm
S r (OR)4-m, specifically 5i(O
CH3)4, Si (OC2H5)4, Si
Tetrafunctional silane such as (OCsHy)4, CHsSi
(OCHs)s, CHsSi (OC2H5)3
.

CHsSi (OC3H7)3, CzHsS
i (OCHs)3, CaHs5i(OC
Trifunctional silanes such as Hs)s and CH35i (OCaHs)s.

(CHs)zsi (OCH3)21 (CHs)z
si (OCzHs)z.

(CH3)zsi (OCsHy)2* (CzHs
)zsi (OCJ-13)2 *(CaHs)zsi
(OCH3)21 (CHs)zsi (OCaHs
) z and other difunctional silanes. These silane compounds can be used alone or in combination of two or more.

The metal alkoxide compound used in the present invention is:

It is represented by the general 2M(OR')n, specifically B(0
-i C3H7)! , Mg(OC3H7)2,
P (0-i C3H?)3.

Ti (0-i C3H7)4, Ti (OCI!
H5)4 etc. are mentioned.

These metal alkoxide compounds can be used alone or in combination of two or more. Also, R in the general formula
and R' may be equal or different.

The copolymerization composition of the silane compound and metal alkoxide compound used in the present invention is preferably in the range of 70 to 90 mol of the silane compound and 10 to 30 mol of the metal alkoxide compound, from the viewpoint of film formability, carbon residue, etc.
Moreover, these silane compounds are either tetrafunctional silane 51 (0 几) 4 or tetrafunctional silane Si (OR) 420-4
0 molti, trifunctional silane R8i (OR)s 20~
60 molti, and bifunctional silane R2Si (OR)2
Preferably, it is a mixture having a molar ratio of 0 to 40.

From the viewpoint of film-forming properties, the solvent used in the present invention is an alcohol having the same number of carbon atoms as the alkyl group or aryl group in the silane compound, or an amide such as N,N-dimethylformamide that does not react with the alkyl group or aryl group. A system solvent is used. These may be used in combination.

Examples of the reaction catalyst used in the present invention include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, and hydrofluoric acid.

Oxides such as phosphorus pentoxide and boron oxide, organic acids such as oxalic acid, and the like are used. The amount of the catalyst added is preferably 0.1 to 5% by weight in total based on the silane compound and metal alkoxide compound.

The coating liquid of the present invention is obtained by hydrolyzing and condensing the alkoxysilane compound and the metal alkoxide compound using the catalyst in the presence of a solvent.

Further, the thermal expansion coefficient of the oxide film obtained using the solution can be arbitrarily changed depending on the type and amount of the selected metal alkoxide compound.

When forming an oxide film using the coating liquid of the present invention, silicon, glass, and ceramics are used.

After applying the coating liquid onto the surface of a substrate such as aluminum using a spinner, sprayer, etc.9, the temperature is usually 50 to 200°C, preferably! I'1 Dry at 1100-150℃ 9 then usually 4
Firing is performed at 00 to 800°C, preferably 400 to 500°C.

The oxide film obtained using the coating liquid of the present invention is as follows.

Compared to the oxide film obtained using conventional silanol metal condensates, it has a lower carbon content and contains magnesium, phosphorus, phosphorus, zirconium, yttrium,
Contains oxides of titanium or barium, which are 81
Since it forms a copolymer with 02, it is thermally stable and has good film forming properties.

(Example) The present invention will be explained in detail below with reference to nine examples.

Example I Si (OCJ(3) 451 g, CH35j (O
CH3)3 45 g+(CH3)zsi(OCHs)
z 12 g, B(i-OCsHy)s 31 g
, Mg(OC3Ht)z 109 was dissolved in a mixed solvent of N,N-dimethylformamide 1609 and methyl alcohol 409, and oxalic acid 0.6 was added to this solution.
Hydrolyze by adding 559 g of water dissolved in it.

Condensation was performed to prepare one reactant solution.

This solution was applied to Si using a spinner at 3000 rpm.
After coating on a wafer, it was dried at 150° C. for 1 hour and then baked in an electric furnace at 400° C. for 1 hour, resulting in a colorless, transparent, crack-free silica-based coating.

The thickness of the silica-based coating was measured using a 9 surface roughness meter (trade name: Talystep, manufactured by Rank Taylor Hopson) and found to be 0.7 μm. In addition, when the absorption spectrum of the coating was measured using an infrared spectrophotometer, it was found that 5i
In addition to O-8i absorption.

Absorption of Mg-0 and B-0 bonds was observed, and it was confirmed that the film was a complete oxide film. Furthermore, this oxide film was treated at 400 W for 20 minutes using a barrel-type oxygen plasma ashing device PR-501A (Yamato Kagakusha Exhibition), but no cracks were observed in the film.

In addition, the solution was applied to Si on which an aluminum pattern with a thickness of 0.7 μm and a line and space width of 0.5 to 5 μm was vapor-deposited.
When a film was formed on a wafer under the same conditions as above, a colorless and transparent oxide film without cracks was obtained.

After further drying the solution at 150° C. for 3 hours.

The obtained powder was compression molded into a pellet shape with a diameter of 12 Mn, and fired at 1000° C. for 1 hour in an electric furnace.

The thermal expansion coefficient of this sample was measured using a thermal physical tester T manufactured by Rigaku Denki Co., Ltd.
When measured with MA8150 model, the average linear thermal expansion coefficient from room temperature to 450° C. was 7.0×10”.

Example 2 Si (OCzHg) 4145 g, P (OC3H
7) 3 41 y.

14 g of Mg (OC3H?12) was dissolved in 3009 ethyl alcohol, and 66 g of water in which 0.8 g of oxalic acid had been dissolved was added to the solution for hydrolysis and condensation to prepare a reaction product solution.

When this liquid was applied onto a Si wafer under the same conditions as in Example 1, dried, and fired, a colorless, transparent, crack-free silica-based film with a thickness of 0.5 μm was obtained. Further, the solution was applied to S on which an aluminum pattern was vapor-deposited under the same conditions as in Example 1.
When a film was formed on an i-wafer, a colorless and transparent oxide film without cracks was obtained.

Example 3 Si (OC2H5) 469 g, CH35i fO
c2Hs) 359 g.

(CH3)25i (OC2H5)2259. B(0
-i C3H7) 3319 is dissolved in a mixed solvent of ethyl alcohol 269 and N,N-dimethylformamide 1059, and water 569 in which 0.6 g of oxalic acid is further dissolved is added to this solution to perform hydrolysis and condensation. 1. A reactant solution was prepared.

When this solution was deposited under the same conditions as in Example 1 on a Sl wafer on which Si sea urchin and aluminum patterns had been deposited, a colorless and transparent oxide film with a thickness of 0.7 μm and no cracks was obtained. Ta.

Example 4 451 g of Si (OCH3), CHsSi (
OCH3) 330 g.

C5HsSi (OCHs)s 229. (CH3
)zsi (OCH3)212 g, B(i 0
03Hy) 331 g, Mg(OCaH7)zl 0
g'& diethylene glycol diethyl ether 200
5 g of water and 0.59 g of phosphoric acid dissolved in this solution.
59 was added to perform hydrolysis and condensation.

A reactant solution was created.

When this solution was deposited under the same conditions as in Example 1 on Si Ueno-- and Si Ueno-1- on which an aluminum pattern had been deposited, a colorless, transparent, crack-free oxide film with a thickness of 0.8 μm was obtained. Ta.

Comparative Example I Si (53435 g of OC2H was dissolved in ethyl alcohol 6
49 and ethyl acetate 269, and water 129 in which 0.5 g of oxalic acid was further dissolved was added to perform hydrolysis and condensation to prepare a silanol oligomer solution.

When this solution was applied onto Sl Ueno-- in the same manner as in Example 1, a film of about 0.4 μm was obtained, but the film had many cracks.

Comparative example 2 Si (OCH3)4179, CHsSi (OC
H3)s 25 g and (CHs)2si(OCH
3) z 5 g to N,N-dimethylformamide 4
The silanol oligomer solution was dissolved in a mixed solvent of 8G and methanol 69, and water 209 in which phosphoric acid o and sg were further dissolved was added to perform hydrolysis and condensation to prepare a silanol oligomer solution.

When this solution was applied onto 8i Ueno in the same manner as in Example 1, a film of about 0.7 μm was obtained.

When the absorption spectrum of the film was measured using an infrared spectrophotometer, strong absorption of Si-CH3 was observed in addition to 5i-0-8i absorption, and it was confirmed that the film was not a complete KSiCh film. In addition, this film was prepared in the same manner as in Example 1.
When oxygen plasma treatment was performed at 00W for 20 minutes, cracks occurred in the film.

(Effects of the Invention) The coating solution for forming an oxide film of the present invention is thermally stable and has excellent film-forming properties, so that the oxide film formed on the surface of the substrate using the coating solution has a thickness of 1.5 μm. No cracks occur even at a certain thickness. Therefore, the coating liquid for forming an oxide film of the present invention can be applied to electronic parts.

In particular, coatings for interlayer steps in semiconductor multilayer wiring.

It is effective for flattening the surface of devices such as magnetic bubble memories.

Claims (1)

[Claims] 1. (A) General formula RmSi(OR)_4_-_m (wherein R is an alkyl group or aryl group having 1 to 4 carbon atoms, m
means an integer from 0 to 2), and (B) a silane compound represented by the general formula M(OR')n (wherein M is a metal of magnesium, boron, phosphorus, zirconium, yttrium, titanium, or barium); Atom, R' is an alkyl group or aryl group having 1 to 4 carbon atoms, and n means the valence of the metal atom M) is hydrolyzed using a catalyst in the presence of a solvent. , a coating liquid for forming an oxide film, comprising a reactant obtained by condensation. 2. After coating the coating liquid according to claim 1 on the substrate surface,
A method for producing an oxide film by drying at ~200°C and then firing at 400-800°C.