JPH0263057A - Photosensitive heat resistant resin composition and production of integrated circuit - Google Patents

Abstract

PURPOSE:To enable to prepare a flattened integrated circuit provided with through-holes required to be formed as layer insulation by using a specified organosilicon polymer having silanol groups substituted by specified triorganosilyl groups, in the polymer. CONSTITUTION:An organosilicon polymer described in the 'PURPOSE' is expressed by the formula I and has 3,000-5,000,000 weight average mol.wt., wherein silanol groups contained in the polymer are expressed by the formula II and substituted by triorganosilanol groups contg. at least >=5% lower alkenyl group. In the formulas I and II, R1 is H, OH group, lower alkyl group, etc.; R2 is arylene group; n is an integer 10-50,000; R is lower alkenyl group, lower alkyl group, or aryl group, which may be same or different to each other. Thus, an insulating film having flattening function and through-holes opened therein is obtd.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to put into practical use a resin composition made of an organosilicon polymer that is photosensitive and has excellent heat resistance. A polyorganosylarylene siloxane represented by the general formula (Rz)l/□]7, in which the hydrogen atom of the silanol group contained in this polymer is substituted with a triorganosilyl group represented by (R)zsi- A resin composition is constructed using the following.

[Industrial application field]

The present invention relates to a photosensitive heat-resistant resin composition.

Due to the need to process large amounts of information at high speed, semiconductor devices are becoming increasingly integrated, and LSI and VLSI have been put into practical use.

Conventional integration is achieved by miniaturizing unit elements, and submicron wiring is used as the minimum line width, and patterns are formed on the insulating film formed on the semiconductor substrate to be processed. Formed and used.

On the other hand, in order to increase the degree of integration, three-dimensional structures are being studied instead of such two-dimensional structures.

That is, after forming an integrated circuit having a two-dimensional structure using a silicon (St) single crystal substrate, a chemical vapor deposition method (Chemical Vapor Deposition method) is applied thereon.
An insulating layer is created using ion (CvD method) or a spin code method, and a pie hole is formed using photolithography and an electronic circuit is formed.
By repeating this process, multilayering is achieved and an LSI having three-dimensional wiring is formed.

In this way, the degree of integration has been improved by multilayering, but in order to improve reliability, it is necessary to use an insulating film that has excellent heat resistance and flatness, and also allows easy formation of through holes that connect upper and lower conductor lines. formation is necessary.

[Conventional technology]

Integrated circuits are formed not only on semiconductor devices but also on electronic components such as magnetic bubble memory devices, but they are typically formed on Si single crystal substrates (wafers), and LSI
It is a semiconductor integrated circuit (IC) that constitutes a VLSI.

Hereinafter, conventional techniques and problems will be explained using a Si integrated circuit as an example.

In forming Si integrated circuits, a combination of inorganic and organic insulating films are used as insulating films.

That is, silicon dioxide (5tOz) is used as the inorganic insulating film.
, silicon nitride (5i3N4L phosphosilicate glass (abbreviated as psG)
etc., and is formed by heat treatment, CVD method, etc.

However, although SiO□ films made by heat treatment, 5iOz films, 5i3Nn films, and PSG films made by CVD methods have excellent heat resistance, they require flattening to faithfully reproduce the unevenness of the underlying substrate. It doesn't serve the purpose.

Therefore, when forming semiconductor devices, if there is a significant step difference, there is a risk that thin and submicron-width wiring will easily break, so the above-mentioned method is recommended for applications that require planarization. It is difficult to use an inorganic insulating film alone, and a method of flattening the surface by spin-coating an organic compound with excellent heat resistance is being used.

Organic silicon compounds soluble in organic solvents, such as polyorganosilsesquioxane, have been used as organic insulators suitable for this purpose and having excellent heat resistance.

This polyorganosilsesquioxane is made by using organotrichlorosilane or organotrialkoxysilane as a starting material, hydrolyzing this compound, and then dehydrating and condensing it, but the trifunctional silicone is used as the structural unit. The organosilicon compound, which partially or entirely has a ladder-shaped structure, is soluble in an organic solvent, and can be coated using a spin coating method to form an insulating film.

In addition, as an organosilicon compound with excellent heat resistance and a linear structure, there is polytetramethylsilphenylene siloxane, which has alternating siloxane bonds and diarylene bonds, and this is 1,4-bis(hydroxydimethylsilyl). ) It is made by dissolving benzene in benzene and condensing it under reflux conditions while removing the water produced.

However, when these organosilicon polymers are used in the planarization process of semiconductor devices and subjected to heat treatment at 400°C or higher,
There was a problem in that the insulating film cracked because it could not withstand stress caused by internal strain caused by decomposition and hardening reactions and the difference in thermal expansion coefficient with the wiring material, and an improvement was needed.

[Problem to be solved by the invention]

As described above, conventional insulating films made of organic silicon polymers have a problem in that they are susceptible to cranking during the formation of semiconductor devices.

In addition to using the insulating film for planarization, it is also necessary to provide through holes in the insulating film to connect the upper and lower wiring layers to the circuit.

The conventional method for forming these through holes is to coat the insulating film with photoresist, selectively irradiate it with ultraviolet rays, develop it to create a resist pattern, and then dry-etch it to form the through holes. However, if the organosilicon compound itself has photosensitivity without such a complicated process, through-holes can be easily formed, which greatly contributes to shortening the process.

Therefore, the challenge is to put organic silicon compounds into practical use that can solve these concerns.

[Means to solve the problem]

The above problem is an organosilicon polymer represented by the general formula (1) and having a weight average molecular weight of 3000 to 5.000.000, in which the silanol groups contained in the polymer are (
The problem can be solved by using a photosensitive heat-resistant resin composition represented by the formula 2), which is substituted with a triorganosilyl group containing at least 5% of lower alkenyl groups.

(R, 5t(hz□(Rz)+z□)7...
(1) However, R1 is hydrogen, a hydroxy group, a lower alkyl group, a lower alkoxy group, R2 is an arylene group, n is an integer of 10 to 50,000, (R)zsi-... (2) However, R is lower alkenyl represents a group, a lower alkyl group, or an aryl group, and may be the same or different.

[Effect]

The inventors used (R+5iOtzz(Rz)+/z) rr as an insulating material to eliminate the occurrence of cranks in device formation and to obtain negative photosensitive characteristics.
...We propose the use of a silicon polymer represented by the general formula (1), where R1 is a hydroxy group, a lower alkyl group, or a lower alkoxy group, and R is a phenylene group (-C6H*-), etc. This is a polymer or mixture of organosilicon materials represented by the following two structural formulas.

Here, R1 is a hydroxy group, lower alkyl group or lower alkoxy group, and R is a lower alkenyl group.

It may be any of a lower alkyl group, a lower alkoxy group, or an aryl group, but it is necessary that at least 5% or more of the group consists of a lower alkenyl group.

In other words, lower alkenyl groups such as vinyl groups and allyl groups are highly sensitive to irradiation with high-energy rays such as ultraviolet rays, excimer laser light, or ionizing radiation and cause crosslinking reactions, making it easy to form negative patterns. Become.

One advantage of the present invention is that the steps required for forming through holes in the manufacturing process of semiconductor devices can be reduced, and thus manufacturing costs can be reduced.

Here, the arylene group is not particularly limited as long as it is an organic group having a benzene skeleton, but practically a p- or m-phenylene group is preferred.

In addition, the ratio of the diarylene bond and the siloxane bond in the molecular chain of the polyorganodylarylene siloxane may be any value, but from the viewpoint of heat resistance, the ratio is 25% by weight.
It is desirable to have the above diarylene bond.

In addition, since the hydrogen (I4) atom of the silanol group at the end of the organosilicon polymer represented by general formula (1) is replaced with a trio-organosilyl group (R), +Si-, the crosslinking density decreases. , which increases flexibility and makes it less prone to cranking.

Here, as a method for substituting H- of the silanol groups shown in formulas (3) and (4) with (R)3Si-, these organosilicon polymers are replaced with triorganosilane (R)sSiX. Hexaorganodisilazane (R) 3SiNH3i (
R) 3hexaorganodisiloxane (R) sS
iOs 1(R) 3 However, R may be a vinyl group, a lower alkyl group, or an aryl group, and may be the same or different.

X is halogen, cyano group, isocyanate to group or isothiocyanato group, It is sufficient to react with any of the following.

Note that the organosilicon polymer (polyorganosyl arylene disiloxane resin) according to the present invention is soluble in many organic solvents, and can be applied onto a half-door body fluid-treated substrate by a spin code method and flattened. Can be done.

In addition, it is possible to form a negative pattern by irradiation with ultraviolet rays, excimer laser light, ionizing radiation, etc., and therefore it is possible to create through holes that need to be formed when used as an interlayer insulating layer without using a resist. .

Furthermore, regarding heat resistance, the film quality can be maintained without undergoing thermal oxidation up to 400° C. or higher.

〔Example〕

Example 1: (Synthesis Example 1) 100 cc of methyl isobutyl ketone and 50 cc of methyl cellosolve acetate were placed in a 300'cc fourth flask.
Then, 30 cc of water was added, and 15 cc of triethylamine was added thereto as a catalyst, and the mixture was cooled to -60°C while stirring.

Separately 1,4-bis(methyldichlorosilyl)benzene 1
A sample of 0 g was dissolved in 50 cc of tetrahydrofuran and added dropwise to the fourth flask over 40 minutes.

After dropping, the system was heated at a rate of 2.0°C/min to 80°C.
and continued stirring for 2 hours.

After the reaction was completed, it was cooled to room temperature and washed with a large amount of water.

The reaction solution washed with water was further subjected to azeotropic distillation to remove remaining water.

Thereafter, 20 cc of pyridine was added as a catalyst, and after heating to 60° C., 20 cc of vinyldimethylchlorosilane was added and reacted at this temperature for 3 hours to replace the hydrogen atoms of unreacted hydroxyl groups with vinyldimethylsilyl groups.

After the reaction was completed, the reaction solution was poured into a large amount of water to precipitate the resin, which was recovered and freeze-dried to obtain 5.1 g of white powder.

The weight average molecular weight determined by gel permeation chromatography in terms of polystyrene was 3.5.
It was XIO'.

Example 2: (Synthesis Example 2) Add 100 cc of methyl isobutyl ketone, 50 cc of methyl cellosolve acetate and 30 cc of water to a 300 cc fourth flask, add 15 cc of triethylamine as a catalyst, and heat to -60°C while continuing to stir. Cooled.

Separately 1,4-bis(methyldichlorosilyl)benzene 1
A solution of 0 g dissolved in 50 cc of tetrahydrofuran was prepared, and the solution was added dropwise to the four-necked flask over 40 minutes.

After dropping, the system was heated at a rate of 2.0°C/min to 80°C.
and continued stirring for 2 hours.

After the reaction was completed, it was cooled to room temperature and washed with a large amount of water.

The reaction liquid clogged with water was further removed by azeotropy to remove remaining water.

Then, 20cc of pyridine was added as a catalyst and the mixture was heated to 60°C.
Then, vinyldimethylchlorosilane LOcc and phenyldimethylchlorosilane 10cc were added and reacted at this temperature for 3 hours to replace the hydrogen atoms of unreacted hydroxyl groups with vinyldimethylsilyl groups and phenyldimethylsilyl groups.

After the reaction was completed, the reaction solution was poured into a large amount of water to precipitate the resin, which was recovered and freeze-dried to obtain 5.2 g of white powder.

The weight average molecular weight determined by gel permeation chromatography in terms of polystyrene was 3.4.
It was XIO'.

Example 3: (Formation of semiconductor IC 5, related to Synthesis Example 1) The white powder obtained in Synthesis Example 1 was dissolved in methyl isobutyl ketone to prepare a 20% by weight resin solution.

This resin solution was applied to the first layer of poly-Si wiring (1 μm thick,
Si with minimum line width of 1 μm and minimum line spacing of 1.5 μm)
Spin coding was performed on the substrate at 3000 rpm for 45 seconds.

After coating, the solvent was dried at 80°C for 20 minutes,
Further heat treatment was performed at 250°C for 30 minutes and at 400°C for 60 minutes.

The level difference on the substrate surface after the heat treatment was about 0.2 μm, and the level difference caused by the wiring had been flattened.

Next, through-holes are formed and a second layer of poly-Si wiring is formed, and a 1 μm thick PSC film is deposited as a protective layer by atmospheric pressure CVD, and then a window for taking out the electrodes is opened to obtain a semiconductor device. Ta.

This device was subjected to a heating test at 450° C. for 1 hour in the atmosphere, and then subjected to 10 thermal cycles at −65 to 150° C., but no defects occurred.

Example 4: (Through-hole formation 2 construction example 1 related) After coating and drying the resin layer in the same manner as in Example 3, irradiation with excimer laser light was performed, leaving only the through-hole portion unirradiated. The resin layer was then immersed in methyl isobutyl ketone to obtain a resin layer in which through holes with a diameter of 2 μm were formed.

After heating and curing, a semiconductor device was obtained in the same manner as in Example 2, but this device was subjected to a heating test at 450°C for 1 hour in the air, and then heated 10 times at -65 to 150°C. I ran the cycle, but no defects occurred.

Example 5: (Formation of a composite film with PSG 3 Related to Synthesis Example 1) After forming a resin layer in the same manner as in Example 3 except that the resin was applied at 500 rpm, a layer of 0.3 μm was further formed by atmospheric pressure CVD. A thick PSG film was deposited.

This film flattened the underlying level difference to 0.3 μm.

Thereafter, a semiconductor device was manufactured in the same manner as in Example 3, and the same tests were conducted, but no cracks were observed.

Example 6: (Related to Semiconductor IC Formation Example 1 and Synthesis Example 2) The white powder synthesized in Example 2 was dissolved in methyl isobutyl ketone to prepare a 20% by weight resin solution.

This resin solution is applied to the first layer of poly-Si! l! A (thickness 1
Spin coding was performed on a Si substrate with a minimum line width of 1 μm, a minimum line width of 1 μm, and a minimum line spacing of 1.5 μm under conditions of 300 rpm and 45 seconds.

After coating, dry the solvent at 80℃ for 20 minutes,
Further heat treatment was performed at 250°C for 30 minutes and at 400°C for 60 minutes.

The level difference on the substrate surface after the heat treatment was about 0.2 μm, and the level difference caused by the wiring had been flattened.

Next, through-holes are formed and a second layer of poly-Si wiring is formed, and a 1 μm thick PSC film is deposited as a protective layer by atmospheric pressure CVD, and then a window for taking out the electrodes is opened to obtain a semiconductor device. Ta.

This device was subjected to a heating test at 450° C. for 1 hour in the atmosphere, and then subjected to 10 thermal cycles at −65 to 150° C., but no defects occurred.

Example 7: (Through Hole Formation 2 Related to Formation Example 2) After coating and drying the resin layer in the same manner as in Example 6, irradiation with excimer laser light was performed, leaving only the through hole portion unirradiated. The resin layer was then immersed in methyl isobutyl ketone to obtain a resin layer in which through holes with a diameter of 2 μm were formed.

After heating and curing, a semiconductor device was obtained in the same manner as in Example 2, but this device was subjected to a heating test at 450°C for 1 hour in the air, and then heated 10 times at -65 to 150°C. I ran the cycle, but no defects occurred.

Example 8: (Used in combination with PSG layer 5 Related to Synthesis Example 2) After forming the resin layer in the same manner as in Example 6 except that the resin was applied at 500 rpm, a 0.3 μm thick film was further formed by atmospheric pressure CVD. A PSG film was deposited.

This film flattened the underlying level difference to 0.3 μm.

Thereafter, a semiconductor device was manufactured in the same manner as in Example 6, and the same tests were conducted, but no cracks were observed.

〔Effect of the invention〕

According to the present invention, a new and useful organosilicon polymer can be efficiently produced by a simple method.

Furthermore, it is possible to form a semiconductor tC having an insulating film that has a planarization function and does not cause damage even when used in a high-temperature oxygen atmosphere.

Furthermore, when forming a semiconductor IC, through holes between wiring layers can be formed by directly irradiating ionizing radiation without using a resist.

From the above, it becomes possible to efficiently manufacture a highly reliable semiconductor IC.

Claims (2)

[Claims] (1) Represented by the general formula (1), with a weight average molecular weight of 3
000 to 5,000,000, wherein the silanol group contained in the polymer is represented by the formula (2) and is composed of a triorganosilyl group containing at least 5% or more of a lower alkenyl group. A photosensitive heat-resistant resin composition characterized by being substituted. [R_1SiO_2_/_2(R_2)_1_/_2]
_n...(1) However, R_1 is hydrogen, hydroxy group, lower alkyl group, lower alkoxy group, R_2 is arylene group, n is an integer of 10 to 50,000, (R)_3Si-...(2) However, R is lower alkenyl represents a group, a lower alkyl group, or an aryl group, and may be the same or different. (2) The organosilicon polymer according to claim 1 is used as an insulating film, or selectively irradiated with ultraviolet rays or ionizing radiation to form through holes and used as an interlayer insulating film. A method for manufacturing integrated circuits.