JPH04184444A - Production of photosensitive heat resistant resin composition and semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a photosensitive resin compsn. not causing cracking at the time of heat treatment by using a resin represented by a specified formula and enabling the formation of a negative pattern by irradiation with UV rays. CONSTITUTION:A resin represented by formula I is used and the formation of a negative type pattern by irradiation with UV rays is enabled. In the formula I, each R<1> is 1-3C lower alkyl or aryl, plural R<1>'s may be different from each other, >=20% of plural R<2>'s are ethylene oxide, the remainder is vinyl, lower alkyl or aryl and each of n, m and l is a positive integer. The resin can satisfy both photosensitivity and heat resistance because it contains ethylene oxide as mentioned above and a photosensitive heat resistant resin compsn. not causing cracking at the time of heat treatment is obtd.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for forming an insulating film made of an organic silicon polymer, the following method is used for the purpose of forming a flat insulating film using a resin that is photosensitive and has excellent heat resistance. It is represented by the composition formula of
A photosensitive heat-resistant resin composition that can form a negative pattern by irradiation with ultraviolet rays is used, and the photosensitive heat-resistant resin composition is applied onto the semiconductor substrate on which the wiring pattern has been formed to form a resin film. A semiconductor characterized by forming a pattern made of a resin film by irradiating ultraviolet rays except for the pattern forming part, developing it, and then forming an insulating film on the substrate to obtain a flat insulating film. A method for manufacturing the device is configured.

(Si02), (R'SiO+ s)
(SIR23), (1) R1 represents a lower alkyl group or aryl group having j to 3 carbon atoms, and may be the same or different.

At least 20% of R2 is ethylene oxide, and the remainder is vinyl, lower alkyl, or aryl.

n, m, and 1 represent positive integers.

[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 have become increasingly integrated, and LSI and VLSI have been put into practical use.

Conventionally, integration has been achieved by miniaturizing unit elements, and along with this, the minimum line width of conductor wiring has also come to be in the submicron range.

Additionally, to improve the degree of integration, a three-dimensional structure has been adopted instead of a two-dimensional structure.

That is, after forming an integrated circuit with a two-dimensional structure using a silicon (S) single crystal substrate, a chemical vapor deposition method is applied on the integrated circuit.
An insulating film is created using a method such as ion (abbreviated as C to ID method) or a spin code method that coats a resin composition, and after forming a pie hole using photolithography, a second layer of wiring is formed on top of this. However, by repeating this process, multiple layers are created.

In this way, the degree of integration is improved by multilayering, and I
This requires excellent heat resistance and flatness, as well as the formation of through holes to connect the upper and lower conductor lines, or the easy formation of an insulating film.

[Conventional technology]

In the manufacture of semiconductor integrated circuits, a large number of semiconductor elements and conductor lines are formed on a semiconductor substrate, so the surface thereof is uneven and has steps.

Therefore, the interlayer insulating film formed thereon must not only have excellent insulation properties but also be able to flatten the surface.

An inorganic insulator or an organic insulator is used as an insulating film between the eyebrows.

And, as an inorganic insulator, silicon dioxide (S]02),
Examples include silicon nitride (5iJ4) and phosphosilicate glass (abbreviated as PSG), and are formed on a substrate to be processed by a CVD method or the like.

However, SiO□ film made by CVD method, S+3N
4 film and PSG film are excellent in terms of heat resistance.
, it does not serve the purpose of planarization because it faithfully reproduces the unevenness of the underlying substrate.

Therefore, the bias sputtering method, which deposits and etches the inorganic film at the same time and forms a flat inorganic film while scraping the convex parts of the film, and the bias sputtering method, which forms a resin film as an upper layer and separates the resin film and the inorganic film, are used. Etch-back methods that obtain a flat insulating film through controlled etching are being considered.

In addition, it is necessary to form through holes in the interlayer insulating film to connect the electronic circuits formed above and the electronic circuits formed below, and if an inorganic insulating film is used, it is necessary to form a photoresist. Depending on the photo-etching technique (lithography) used, it is necessary to make holes in the insulating film again.

On the other hand, the spin-coding method can be used to form an organic insulating film, and this method is advantageous because it allows a flat film to be formed on a substrate with steps, and the material is an organic compound with excellent heat resistance. Polymers are attracting attention.

However, conventionally used polyimide has an angle of about 450°.
There are problems in that C may cause decomposition, it is highly hygroscopic, and it contains alkali metals as impurities.

Another problem is that silicone resins are oxidized at temperatures of about 400° C., or undergo thermal decomposition at temperatures above 500° C., and the resulting distortion tends to cause cracks in the film.

Furthermore, when these resins are subjected to oxygen plasma treatment, there is a problem in that degassing and cracking due to oxidation can be observed.

Therefore, a resin with high heat resistance and low moisture absorption is required.

In addition, it is desirable to develop a photosensitive resin that is photosensitive itself for the formation of through-holes and undergoes cross-linking polymerization when irradiated with ionizing radiation such as ultraviolet rays, which fully satisfies these requirements. Resin compositions that do this have not yet been put to practical use.

[Problem to be solved by the invention]

Requirements for the resin composition used as a material for forming interlayer insulating films in the formation of integrated circuits are: 1. It must be heat resistant to 450°C or higher and will not crack during heat treatment; 2. It must be free from corrosive impurities such as alkali metals. ■It is photosensitive and can form fine through-hole patterns.

Furthermore, in order to form an integrated circuit with excellent reliability, it is necessary to establish a technique for forming an interlayer insulating film with excellent flatness.

[Means to solve the problem]

The above problem is solved by using a photosensitive heat-resistant resin composition that can form a negative pattern by irradiation with ultraviolet rays. A resin film is formed by coating the substrate, and after irradiation with ultraviolet rays except for the wiring pattern forming area, development is performed to form a pattern made of the resin film, and then an insulating film is further formed on the substrate to make it flat. This problem can be solved by configuring a method for manufacturing a semiconductor device that is characterized by obtaining an insulating film.

(Si02)ゎ (R'5i01.5)yu (S+R2
5)+...(1) R1 represents a lower alkyl group or aryl group having 1 to 3 carbon atoms, and may be the same or different.

R2 is at least 20% ethylene oxide, and the remainder is vinyl, lower alkyl, or aryl.

n, m, l represent positive integers.

[Effect]

The present invention constitutes an interlayer insulating film using a polyorganosiloxane resin represented by the general formula (1).

The resin represented by the general formula (1) is characterized in that R2 contains at least 20% of ethylene oxide, and therefore can achieve both photosensitivity and heat resistance.

In addition, n is an integer of 10 to 101000, m is 0 to 10
,000, and I represents an integer from 8 to 1000.

Furthermore, this resin has negative photosensitivity, and by irradiating it with ultraviolet rays before heat curing and developing it with an organic solvent, it is possible to form any pattern such as through holes.

In addition, in order to form a flat interlayer insulating film using an organic silicon compound having such photosensitivity, it is necessary to coat the resin composition on the substrate on which the wiring of the first layer is formed by a spin-coating method. By irradiating and developing ultraviolet rays on areas other than the areas where the wiring of the -th layer is formed, the resin film is left only on the areas where the wiring is not formed.

Next, if an insulating film is formed on this by the conventional CVD method or spin code method, a flat interlayer insulating film can be formed.

Ru.

〔Example〕

Synthesis Example 1: (Corresponding to Claim 1) In a 1000 cc fourth flask, 25.8 g (0.2 mol) of hexamethyldisiloxane, 80 g of concentrated hydrochloric acid, 120 g of ion exchange water, 60 g of methanol, and 300 cc of methyl isobutyl ketone were added. After heating to reflux temperature in a water bath, add 30.44 g of tetramethoxysilane.
(0.2 mol) was slowly added dropwise over 2 hours using a dropping funnel.

After the completion of the dropwise addition, heating was continued for about 30 minutes to obtain a polymer bomb having a molecular weight of 5.0 Xl03 (in terms of polystyrene).

After removing the aqueous layer of this resin solution, pyridine 100c
100 cc of dimethylvinylchlorosilane
was added to silylate unreacted silanol residues.

After the silylation was completed, the organic layer was washed with water and methanol was added to the organic layer to precipitate and recover the polymer.

Next, the freeze-dried second polymer was dissolved in dichloromethane, kept at 20°C in a water bath, and mixed with peracetic acid at 30°C.
C was added.

After the reaction was completed, it was washed 5 times with a 0.5% aqueous solution of sodium bisulfite, and then washed 10 times with pure water.

After washing, 20 g of white powder was collected in the same manner as the hair polymer.

The synthesized resin was dissolved in methyl isobutyfuketone and 25
% resin solution by weight.

Synthesis Example 2 (Corresponding to Claim 1) Put 16.24 g (Oi mol) of hexamethylchloroxane, 80 g of concentrated hydrochloric acid, 120 g of ion-exchanged water, 80 g of methanol, and 100 cc of methyl isobutyl ketone into a 1000 cc four-loaf flask, and place in a water bath. After heating to reflux temperature, 30.44 g of tetramethoxysilane
(0°2 mol) and methyltrimethoxysilane 15.2
Using a dropping funnel, a mixture of 1 mol of g CO was slowly added dropwise over a period of 2 hours.

After the dropping was completed, heating was continued for about 30 minutes (y,
A noricorn polymer having a molecular weight of 3.0 XIO' (in terms of polystyrene) was obtained.

After removing the aqueous layer of this resin solution, pyridine 150c
150 cc of dimethylvinylchlorosilane
was added to silylate unreacted silanol residues.

After the silylation was completed, the organic layer was washed with water and methanol was added to the organic layer to precipitate and recover the polymer.

Next, this freeze-dried polymer was dissolved in dichloromethane and kept at 20°C in a water bath.
CC was added.

After the reaction is completed, 0°596 of sodium bisulfite
It was washed 5 times with an aqueous solution, and then washed 10 times with pure water.

After washing, 20 g of white powder was collected in the same manner as the hair polymer.

Example 1. (Example of forming an integrated circuit with through-holes) The resin solution prepared in Synthesis Example 1 was placed on a Si substrate on which semiconductor elements were formed and layer A1 wiring was applied.
Spin coded to a thickness of μm.

At the knee, the thickness of the Aj7 wiring is 1 μm, and the minimum line width is 1 μm.
, the minimum line spacing is 1.5 μm.

After coating, the solvent was dried at 80°C for 20 minutes, followed by irradiation with excimer laser light using an exposure mask except for the through-hole formation area, and the through-hole was immersed in isopropyl alcohol. A resin layer was obtained.

At this time, the diameter of the through hole is 1.5 μm, and then,
The Si substrate was heat-treated at 450°C for ] hours in a N2 stream.

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

Next, conduct the second layer of A7 wiring, and use 1.2 as a protective layer.
After forming a μm-thick PSG film, a window for taking out the electrodes was opened to obtain a semiconductor device.

The second semiconductor device was subjected to a heating test at 450°C for 1 hour in the atmosphere, and no defects were found even after 10 thermal shock tests at -65°C to 150°C.

Example 2: (Corresponding to Claim 2) The resin solution prepared according to Synthesis Example 1 was applied to a Si substrate on which a semiconductor element was formed and a first layer Al wiring was applied.
．． It was spin coded to a thickness of 5 μm.

2\The thickness of the Aβ wiring is 1 μm, the minimum line width is 1 μm,
The minimum line spacing is 1.5 μm.

After coating, the solvent was dried at 80°C for 20 minutes, and then irradiated with excimer laser light using an exposure mask except for the area where the A1 wiring of the first layer was applied, and an alkaline developer was applied. (Product name: MP-312).
A flattened surface was obtained with resin remaining only between the wires.

Next, a PSG film with a thickness of 1 μm was formed thereon by the CVD method, resulting in an interlayer insulating film with no steps.

Next, using a resist formed by electron beam exposure as a mask, a diameter of 0.5 mm was applied. A through hole of czm was formed, a second layer of A1 wiring was formed on this interlayer insulating film, and a PSG film with a thickness of 1.5 μm was formed as a protective film on top of this, thereby completing a semiconductor device.

This semiconductor device was subjected to a heating test at 450°C for 1 hour in the atmosphere, and after 10 thermal shock tests from -65°C to 150°C, no defects were found.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a resin composition that is photosensitive, has excellent heat resistance, and does not generate cracks during heat treatment, and by carrying out the present invention, a resist is used to form through holes when forming a semiconductor device. It is also possible to do this without any additional steps, which can significantly shorten the manufacturing process.

Claims (2)

[Claims] (1) A photosensitive heat-resistant resin composition represented by the following compositional formula and capable of forming a negative pattern by ultraviolet irradiation. (SiO_2)_n(R^1SiO_1_._5)_m
(SiR^2_3)_l...(1) Here, R^1 represents a lower alkyl group or aryl group having 1 to 3 carbon atoms, and may be the same or different. At least 20% of R^2 is ethylene oxide, and the remainder is a vinyl group, lower alkyl group, or aryl group. n, m, l represent positive integers. (2) A resin film is formed by applying the photosensitive heat-resistant resin composition according to claim 1 on the semiconductor substrate on which the wiring pattern has been formed, and after irradiating with ultraviolet rays except for the wiring pattern forming area, development is carried out. 1. A method of manufacturing a semiconductor device, which comprises: forming a pattern made of a resin film, and then forming an insulating film on the substrate to obtain a flat insulating film.