JPH03166228A - Photosensitive heat-resistant resin composition and formation of multi-layer wiring of semiconductor device using same composition - Google Patents

Abstract

PURPOSE:To obtain the title composition useful for semiconductor device, having flattening function and high-sensitivity throughhole pattern forming function by far ultraviolet light irradiation, containing an organosilicon polymer having a specific repeating unit and a given weight-average molecular weight. CONSTITUTION:A polymer having a specific repeating unit shown by the formula (R<1> comprises >=5% unsaturated hydrocarbon, >=5% aromatic compound residue and the rest of lower alkyl if the rest exists; n is 1-6; m is 10-5,000) and 3,000-500,000 weightaverage molecular weight. The objective composition comprising an organosilicon polymer prepared by replacing at least part of H of silanol group remaining at the end of the polymer with a triorganosilyl group shown by the formula (R<2>)3Si-(R<2> is 1-6C alkyl or epoxy) and an azide compound.

Description

Detailed Description of the Invention (Summary of the Invention) This invention relates to a photosensitive heat-resistant resin composition and a method for forming an insulating film of a semiconductor device using the same as an interlayer insulating film. The purpose of the present invention is to provide a photosensitive heat-resistant resin composition which can be formed into a shape and which can be formed into a through hole with high sensitivity by ultraviolet irradiation. /2) II
+ ”・(1) (In the formula, R1 is an unsaturated hydrocarbon group at 5% or more) (In the formula, R1 is an unsaturated hydrocarbon group at 5% or more) (In the formula, R1 is an unsaturated hydrocarbon group at least 5%) If present, it represents a lower alkyl group having 1 to 6 carbon atoms, n represents an integer of 1 to 6, and m represents an integer of 10 to 5000), and 3. 000～soo
, ooo, or triorganosilyl groups ((R
A photosensitive heat-resistant resin composition is composed of an organosilicon polymer substituted with ``)ffSi-) and an azide compound.
INDUSTRIAL APPLICATION FIELD The present invention relates to a photosensitive heat-resistant resin composition and a method for forming an insulating film of a semiconductor device using the same as an interlayer insulating film.

With the increasing integration of semiconductors, miniaturization of unit elements, miniaturization of wiring, and multilayering are widely carried out, and the photosensitive heat-resistant resin according to the present invention is particularly useful as an insulating film between the eyebrows of multilayer wiring. .

[Conventional technology]

A method of using polysylalkylene siloxane as an insulating film between the eyebrows of a semiconductor is known (Japanese Patent Application No. 1-10779).
(See Application No. 7). Furthermore, a method of forming a negative pattern using a resin having a vinyl group or an allyl group in a side chain is also known.

However, silalkylene siloxanes that have unsaturated double bonds such as vinyl groups or allyl groups in their side chains have low sensitivity to deep-UV light and require long exposure when forming patterns. There was a problem (sensitivity 2 J/cJ).

On the other hand, inorganic films that have been conventionally processed using CVD (Chem)
In a method of forming an insulating film on a substrate using a method such as ical vapor deposition, when an insulating film is formed on a semiconductor substrate surface having an uneven surface, the unevenness of the underlying substrate is reproduced as it is on the surface of the film. This causes disconnection of the upper layer wiring and poor insulation of the insulating film. Therefore, there has been a problem in that it has become essential to develop an insulating film that can flatten the unevenness of the underlying substrate.

Therefore, conventional methods for flattening the inorganic film surface are as follows:
After applying the resin by spin coating to obtain a flat surface,
An etch-back method that performs controlled etching of the resin and inorganic film to obtain a flat inorganic film, and a bias sputtering method that attempts to obtain a flat inorganic film by depositing the inorganic film and etching the convex portions at the same time. Such studies have been conducted.

Further, a method of applying a resin by spin coating and curing it by heating to obtain a flat insulating film is also being considered.

[Problem to be solved by the invention]

However, no matter which method is used, in order to form a through hole connecting upper and lower wiring layers,
It is necessary to form a resist pattern on the insulating film and then etch the insulating film, which poses a problem in that many steps are required to form the insulating film.

For these reasons, it has long been desired to establish a method for forming multilayer interconnections using patternable heat-resistant resin materials as semiconductor insulating film materials. Therefore, the present invention
It is an object of the present invention to provide a photosensitive heat-resistant resin composition capable of solving the problems of the prior art described above and forming an insulating film material capable of flattening the surface of a semiconductor substrate.

The present invention also forms through holes connecting upper and lower wiring layers in an insulating film by forming a pattern using a resist on a substrate as in the conventional method, and then etching the insulating film using this as a mask. It is not necessary, and it is possible to form a through hole with high sensitivity by irradiating ultraviolet rays.) (In the formula, R1 is
Moreover, it is an object of the present invention to provide a photosensitive heat-resistant resin that can be used as an insulating film as it is.

[Means to solve the problem]

According to the present invention, the above problem can be solved by formula (I): (R'SiO
z/z(CnHi)+zz) Im (I)
(In the formula, 5% or more of Rl is an unsaturated hydrocarbon group) (In the formula, R1 is an unsaturated hydrocarbon group of 5% or more) (In the formula, R1
represents a lower alkyl group having 1 to 6 carbon atoms, n represents an integer of 1 to 6, and m represents 1
(representing an integer from 0 to 5000) and a weight average molecular weight of 3.000 to 500,000, or silanol groups remaining at the ends of this organosilicon polymer. At least some of the hydrogen atoms are represented by the formula (R")s S f - (wherein, R2 is each independently a lower alkyl group having 1 to 6 carbon atoms, or a lower alkyl group having 6 to 1 carbon atoms.
2, an organosilicon polymer substituted with a triorganosilyl group represented by an epoxy group optionally substituted with an alkyl group or an alkyl group having 1 to 4 carbon atoms, and an azide compound. This can be achieved by a photosensitive heat-resistant resin composition comprising the following, and its use.

According to the present invention, the insulating film material having the formula (1) can be used as an insulating film material that can flatten the underlying level difference in a semiconductor device shape and has a photosensitive characteristic that allows through holes to be opened with high sensitivity by exposure to deep ultraviolet rays. The silalkylene siloxane resin shown below is used. This silalkylene siloxane resin, which has a substituent with an unsaturated double bond in the side chain and an unsaturated hydrocarbon group, has the property of being able to form a negative pattern with high sensitivity by irradiation with deep ultraviolet rays. It's for a reason.

The organosilicon polymer having the repeating unit of the formula (1) is, for example, a repeating unit of the formula (II) and (II[) or a formula (■), (I
II) and (■): X X X R4 is C, ~C + Z
Aryl group or C. -C. Indicates an unsaturated hydrocarbon group such as an aryl group which may be substituted with an alkyl group, and R5
represents C1-C, lower alkyl group, and X represents halogen or C, -C. Low grade? It can be produced by reacting silicon compounds (representing an alkoxy group and n representing an integer of 1 to 6) in any desired ratio, followed by hydrolysis (X→OH) and thermal dehydration polymerization.

For the purpose of the present invention, the organosilicon polymer having the general 2N) repeating unit thus obtained is Rl
is 5% or more of unsaturated hydrocarbon groups, preferably 70% or less, particularly preferably 10 to 40%) (wherein, R1 is a group containing 5% or more of unsaturated hydrocarbon groups, preferably 70% or less, particularly preferably (10 to 40%) (wherein R1 is the remainder lower alkyl (which may be absent).

The weight average molecular weight of this organosilicon polymer is 3,000 to 5.
00,000, preferably 5.000~too,oo
It is o.

According to the second aspect of the present invention, part or all of the hydrogen atoms of the silanol groups (-SiOH) remaining at the ends of the organosilicon polymer having the repeating unit of the general formula (1) are replaced with the triorgan Silyl group (R") 3s t - (wherein, R2 is each independently C, ~ C6 lower alkyl group, 0
6-CI■ indicates an aryl group (a phenyl group or an alkyl or alkenyl substituted product thereof) or an epoxy group optionally substituted with a C, to C4 alkyl group) to produce a silylated organosilicon polymer.

According to the present invention, a photosensitive heat-resistant resin composition is prepared from the organosilicon polymer or silylated organosilicon polymer and an azide compound.

Examples of the azide compounds used in the present invention include azides such as p-azidobenzaldehyde, p-azidoacetophenone, p-azidobenzoic acid, sodium p-azidobenzaldehyde-2-sulfonate, and p-azidoacetophenone; and 4,4'-diazochalcone, 2,6-bis(4'-azidobenzal)cyclohexanone, 2,6-bis(4'-azidobenzal)4-methylcyclohexanone, 1,3-bis(4'-azidobenzal)-2 -propane, p-azitobenzalacetone, sodium p-azidobenzalacetone-2-sulfonate, 1,3-bis(4'-azidocinnamoisodene)-2-propane, 13-bis(4'- azidobenzal)-2-propane 2'-sulfonic acid, 4,4'-
Diazidostilbene-2,2-disulfonic acid, 1,3-
Bis(4'-azidobenzal)-2-propane 2,2'
-disulfonic acid, 2.6-bis(4'-azidobenzal)cyclohexanone 2',2'1'disulfonic acid, 2.
Bisazides such as 6-bis(4'-azidobenzal)-4-methylcyclohexanone-2',2'-disulfonic acid and azidopyrene can be mentioned.

Although there is no particular limitation on the blending ratio of the organosilicon polymer and the azide compound in the photosensitive heat-resistant resin composition according to the present invention,
The azide compound is preferably blended in an amount of 1 to 15% by weight, particularly preferably 5 to 10% by weight, based on the organosilicon polymer.

The photosensitive heat-resistant resin composition according to the present invention can be used in a suitable solvent, such as acetone, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethylene glycol ethers and esters such as methyl cellosolve, acetate, ethyl cellosolve acetate, benzene, etc. , tonoleene, xylene, etc., for example, with a solid content concentration of 5 to 60% by weight, more preferably 15 to 30%.
It can be dissolved in % by weight and applied according to a conventional method. A general-purpose photosensitizer (for example, the above-mentioned azide compound) can be further added to this solution if necessary.

In addition, in the general formula (1), C n H z n is not particularly limited, but lower alkylene such as methylene and ethylene is desirable for practical purposes. Further, the ratio of silalkylene bonds to siloxane bonds in the molecular chain may be any value, but from the viewpoint of heat resistance, it is desirable to include 25% or more of silalkylene bonds. When an organosilicon polymer obtained using such a material is used as an interlayer insulating film, it is surprisingly possible to use a conventional silyl having side chains of unsaturated double bonds such as vinyl groups and allyl groups. Sensitivity is improved by more than an order of magnitude compared to when alkylene resin is used.

Next, the present inventors took into consideration that organosilicon polymers are used on wiring materials with a large coefficient of thermal expansion, such as Al ξ wiring.
As a method of imparting flexibility to the above organosilicon polymer,
The above-mentioned triorganosilyl group (
R") ssi- substituted resin is used. This is because replacing the silanol reduces the crosslink density after heat treatment and increases the flexibility of the membrane.

[Effect]

As explained above, according to the present invention, it is possible to flatten unevenness and steps on the substrate surface by spin coating,
Through deep ultraviolet light exposure, it is possible to form through-hole patterns with high sensitivity, and it is also possible to form interlayer insulating films with excellent heat resistance and crack resistance. This is because the organosilicon polymer of the present invention has a substituent having an unsaturated double bond in the side chain, and at the same time, the silalkylene resin containing an aromatic compound exhibits high sensitivity and negative pattern formation when irradiated with ultraviolet rays. This allows the through-hole to be used as an insulating material that can be self-formed. According to this method, multilayer semiconductor wiring can be easily formed.

That is, when forming multilayer wiring for ICs, LSIs, etc. using the organosilicon polymer, for example, by applying a film using a spin coating method, it is possible to flatten the underlying level difference, and after coating and drying the solvent, deep -υV light irradiation is performed. (In the formula, R1 is The reliability of the device can also be increased.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on Examples, but it goes without saying that the technical scope of the present invention is not limited to these Examples.

Methyl cellosolve 10 in a rainbow 300cc four-eyed flask
0cc and 30cc of ion-exchanged water, and while stirring, add 5g of bis(p-vinyldimethoxysilyl)methane and 5g of bis(p-phenyldimethoxysilinole)methane to 50cc of tetrahydrofuran. The dissolved solution was added dropwise. After the dropwise addition was completed, the reaction mixture was heated to reflux temperature and reacted for 3 hours. After the reaction was completed, 200 cc of methyl isobutyl ketone was added to remove water from the system by azeotropy. The concentration of the obtained resin solution was corrected by adding ethyl cellosolve acetate, and the solution was heated at 5000 rpm.
It was prepared so that it could be coated to a thickness of 1.5 μm under conditions of pm and 45 seconds.

The weight average molecular weight of the obtained resin was 30,000.

This resin solution (resin concentration 25% by weight) was added with an azide compound of 0.0% to the resin solution. 2% by weight of 2,6-bis(4'
-azidobenzal) cyclohexanone was further dissolved to prepare a photosensitive heat-resistant resin composition.

After removing water from the system, pyridine and dimethylphenylchlorosilane were added to the resin synthesized in Main Example 1, and the mixture was reacted at 70°C for 2 hours to synthesize a resin in which the reaction terminal was substituted with trimethylsilyl.

The obtained resin solution was washed with water, and then the resin was precipitated and collected, and a benzene solution was freeze-dried to obtain a resin powder. This resin powder was dissolved in 20% by weight of methyl isobutyl ketone, and an azide compound of 2% by weight was added to the resin solution.
A photosensitive heat-resistant resin composition was prepared by dissolving 6-bis(4'-azidohenzal)cyclohexanone.

The main semiconductor element was formed using silicon-based Fi with the first layer of Poly-Si wiring (the thickness of the Poly-Si wiring was 1 μm).
The photosensitive heat-resistant resin composition prepared in Example 1 (can be coated to a thickness of 1.5 μm on a Si plate) was applied using the Subin coating method at 5000 rpm and 45 seconds on the substrate (minimum line spacing is 1.2 μm). . After coating, heat treatment was performed at 80'C for 20 minutes to dry the solvent. Next, deep-IJ was applied to this membrane.
Irradiated with V light (230 to 260 nm) at an exposure dose of 300 mJ/cfI, organic A 2 μm square through hole was formed by developing with a container (a mixed solution of methylisopropylene ketone and isopropylene alcohol).

Next, this was subjected to heat treatment at 350° C. for 1 hour under a nitrogen stream to form an insulating film. At this time, the level difference on the substrate surface is 0.2 μm) (in the formula, R1 is the I
The micrometer level difference was flattened. A second layer of Poly-Si wiring was further applied on the insulating film formed as described above, and four-layer wiring was sequentially formed in the same steps. No cracks were observed in the formed multilayer wiring.

In Example 3, the photosensitive resin composition of Example 2 was used in place of the photosensitive resin composition prepared in Example 1, and a four-layer wiring was formed in the same process. This semiconductor device is heated at -50°C → 350°C
No cranking was observed even after repeating the thermal cycle at 500°C.

A silicon substrate on which a semiconductor element is formed and a first layer of Al wiring is applied (the thickness of the Al wiring is 1 μm, the minimum line spacing is 1.5 μm).
2 μm) using the Subin coating method at 5000 rpm,
The photosensitive resin composition prepared in Example 2 (S
(can be coated to a thickness of 2 μm on a flat plate). After application,
The solvent was dried by heat treatment at 80"C for 20 minutes. Next,
Deep-UV light (230-260nII1) at 250
A 2 μm square through hole was formed by irradiating with an exposure amount of mJ/cTA and developing with an organic solvent (a mixture of methyl isobutyl ketone and isobrobyl alcohol). Next, heat treatment was performed at 350° C. for 1 hour under a nitrogen stream to form an insulating film. At this time, the level difference on the substrate surface is about 0. 1 μm) (in the formula, R1 indicates that a 1 μm step caused by the wiring has been flattened).

A second layer of Al wiring was further applied on the insulating film formed as described above, and four-layer wiring was sequentially formed in the same steps. No cracks were observed in the formed multilayer wiring. Moreover, this semiconductor device is -50″C→35
Even after repeating the heat cycle at 0''C 500 times, no cranking was observed.

Methyl cellosolve 150 in a 500cc four-bottle flask
cc and 50 cc of ion-exchanged water, and add 50 cc of bis(P-vinyldimethoxysilyl)methane while stirring.
g and bis(p-phenyldimethoxysilyl)methane 5
g and bis(p-methyldimethoxysilyl)methane 5g
A solution prepared by dissolving the above in 70 cc of tetrahydrofuran was added dropwise. After the dropwise addition was completed, the temperature was raised to reflux temperature and the mixture was reacted for 4 hours. After the reaction was completed, 200 cc of methyl isobutyl ketone was added to remove water from the system by azeotropy. The concentration of the obtained resin solution was corrected by adding ethyl cellosolve acetate, and the solution was heated at 5000 rpm for 30 seconds.
．． It was prepared so that it could be applied to a thickness of 5 μm. The weight average molecular weight of the obtained resin was 30,000. In this resin solution (resin concentration: 25%), 2,6-bis(4'-azidobenzal)cyclohexanone was further dissolved as an azide compound in an amount of 2% by weight based on the resin solution to obtain a photosensitive resin composition.

After removing water from the system, pyridine and dimethylphenylchlorosilane were added to the resin synthesized in Example 6 to obtain a 70"
A resin in which the reaction terminal was substituted with trimethylsilyl was synthesized by reacting with C for 2 hours. The obtained resin solution is
After washing with water, the resin was precipitated and recovered, and freeze-dried as a benzene solution to obtain a resin powder. The resin powder was dissolved in 20% by weight of methyl isobutyl ketone, and 2% by weight of 2,6-bis(4'-azidobenzal)cyclohexanone was further dissolved in the resin solution as an azide compound to obtain a photosensitive resin composition. Ta.

A silicon substrate on which the main semiconductor element was formed and the first layer of Poly-Si wiring was applied (the thickness of the Poly-Si wiring was 1 μm).
, the minimum line spacing is 1.2 μm) by spin coating at 5000 rpm for 45 seconds (can be applied to a thickness of 1.5 μm on a Si flat plate).
was applied. After application, heat treatment at 80℃ for 20 minutes, dry the solvent, and then apply Deep-UV light (230~260℃).
2 μm square through holes were formed by irradiating the film with an exposure dose of 300+aJ/cia and developing with an organic solvent (a mixture of methyl isobutyl ketone and isopropyl alcohol). This was then heated under a nitrogen stream for 35 minutes.
An insulating film was formed by heat treatment at 0°C for 1 hour. At this time, the step difference on the substrate surface is approximately 0.1 μm) (where R1 is
The 1 μm step difference caused by the wiring had been flattened.

A second layer of Poly-St wiring was further applied on the insulating film formed as described above, and four-layer wiring was sequentially formed in the same steps. No cracks were observed in the well-formed multilayer wiring.

In Group E Example 8, a four-layer wiring was formed in the same process using the photosensitive resin composition of Example 7 instead of the photosensitive resin composition prepared in Example 6. This semiconductor device is -50'C → 35
No cranking was observed even after repeated thermal cycles at 0° C. in the smooth direction.

A silicon substrate with a patterned semiconductor element and a first layer of AI2 wiring (the thickness of the An wiring is 1 μm, the minimum line spacing is 1.5 μm).
2 μm) by spin coating at 5000 rpm,
The photosensitive resin composition prepared in Example 7 (S
(can be applied to a thickness of 2 μm on the T-plane) was applied. After application,
After heat treatment at 80°C for 20 minutes and drying the solvent, De
ep-UV light (230-260nm) at 250mJ/c
A 2 μm square through hole was formed by irradiating with an exposure amount of J and developing with an organic solvent (a mixture of methyl isobutyl ketone and isopropyl alcohol). Next, this was heat-treated at 350° C. for 1 hour under a nitrogen stream to form an insulating film. At this time, the level difference on the substrate surface is about 0.
1 μm) (in the formula, R1 indicates that a 1 μm step caused by the wiring has been flattened).

A second layer of Al wiring was further formed on the insulating film formed as described above, and four-layer wiring was formed in the same steps. No cracks were observed in the formed multilayer wiring. Also, this semiconductor device has a temperature of -50°C→35°C.
Even after repeating the thermal cycle at 0"C 500 times, no cracks were observed.

〔Effect of the invention〕

When the photosensitive heat-resistant resin composition of the present invention is used to form an insulating film between the eyebrows of a semiconductor device, the resin's flattening function, highly sensitive through-hole pattern formation function by deep ultraviolet irradiation, and high heat resistance can be utilized. This makes it possible to form an insulating film. Further, the formed insulating film can be used without causing cranking due to subsequent heat treatment. This makes it possible to simplify the semiconductor multilayer interconnection process.) (In the formula, R1 is
Manufacturing costs can also be reduced.

Claims (1)

[Claims] 1. General formula (I): [R^1SiO_2_/_2(CnH_2n)_1_/
_2]_m...(I) (wherein, 5% or more of R^1 is an unsaturated hydrocarbon group, 5% or more is an aromatic compound residue, and the rest, if present, is represents a lower alkyl group, n represents an integer of 1 to 6, and m is 10 to 50
has a repeating unit represented by (representing an integer of 00),
and an organosilicon polymer having a weight average molecular weight of 3,000 to 500,000. 2. A photosensitive heat-resistant resin composition comprising the organosilicon polymer according to claim 1 and an azide compound. 3. At least a part of the hydrogen atoms of the silanol groups remaining at the ends of the organosilicon polymer according to claim 1 are replaced by the formula (R^2
)_3Si- (in the formula, each R^2 independently has a carbon number of 1
An organosilicon substituted with a triorganosilyl group represented by an epoxy group optionally substituted with a lower alkyl group having 6 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkyl group having 1 to 4 carbon atoms. A photosensitive heat-resistant resin composition comprising a polymer and an azide compound. 4. A method for forming an insulating film for a semiconductor device, characterized in that the photosensitive heat-resistant resin composition according to claim 2 or 3 is used as an interlayer insulating film in a multilayer arrangement of a semiconductor device.