JPH046563A - Material for intermediate layer in three-layer resist and formation of pattern - Google Patents

Abstract

PURPOSE:To attain formation of a hardened film having uniform thickness without generation of a crack in a short period by using a thermosetting polyorganosiloxane component consisting of a specified polyorganosiloxane and an organic peroxide having a catalytic amount. CONSTITUTION:The thermosetting polyorganosiloxane component for an intemediate layer in a three-layer resist is consisting of the polyorganiosiloxane which has an aliphatic unsaturated group bonded to at least two silicon atoms in the molecule and the softening point is higher than a normal temp, and is soluble in organic solvents, and a catalytic amount of organic peroxide. Hence when an upper layer of the resist is applied, the dissolution coating the upper resist and the dissolution in forming the mixing layer and the dissolution in for the forming of the mixing layer and the development of the upper resist are eliminated. Thus the hardening of the film is performed by a heat treatment in a short period and the by-product in the hardening reaction s hardly generated, so that the hardened film without a cruck is easily formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is a three-layer method for forming fine resist patterns on a substrate with high precision in the manufacture of various solid-state devices including semiconductor integrated circuits. Regarding intermediate layer materials for resist lithography technology, in particular, they have excellent storage stability with little change over time, can be cured with short heat treatment, can form the upper layer resist into a uniform thin film with good workability, and are resistant to oxygen etching. The present invention relates to an intermediate layer material for a three-layer resist that has excellent pattern transferability to a lower resist layer, and a method for forming 1< turns on a substrate using the intermediate layer material.

[Prior Art] In forming patterns on semiconductor substrates in the manufacture of LSIs, bubble memory devices, etc., lithography methods are used that combine a breeding resist and reduction projection exposure using near-ultraviolet light, direct electron beam writing, or X-ray exposure. It is being recent years,
High-precision processing of fine nof turns at the sub-micron level is required as the integration becomes higher.
Instead of conventional wet etching, it has become necessary to use dry etching using gas plasma, reactive sputter etching, ion milling, etc., and with this, it has become necessary to use dry etching techniques such as gas plasma, reactive sputter etching, and ion milling. Excellence is now required.

In addition, in the actual device manufacturing process, it is sometimes necessary to apply a thick resist layer to flatten the steps on the substrate to be processed. In such cases, the resolution of the resist generally decreases. Additionally, as pattern dimensions become finer, the main causes of decreased pattern accuracy are the standing wave effect caused by light reflected from the substrate in the case of light exposure, and the proximity effect caused by reflected electrons in the case of electron beam lithography. This is,
This is an essential problem during exposure that cannot be avoided even if a resist with high sensitivity, high resolution, and high dry etching resistance is used.

To solve these problems, a three-layer resist method was proposed by J.M. Moran in the Journal of Vacuum Science and Technology (J, Vacuum.

Sci, and,Technol,), Volume 16, No. 16
It is proposed on page 20 (1979). this is,
After flattening the steps on the substrate by thickly coating an organic polymer material (lower layer resist) that is highly resistant to dry etching for processing the substrate as the first layer, this first layer is applied as an intermediate layer. An inorganic compound material layer having excellent dry etching resistance using oxygen for processing is formed, and then a resist layer (upper resist layer) is formed as a third layer on this intermediate layer. This resist layer is pattern-exposed by a known method using light or an electron beam, and then developed, and the intermediate layer is dry-etched using the resulting resist pattern as a mask. Subsequently, using this pattern-transferred intermediate layer as a mask, the first layer is processed by oxygen-based dry etching to obtain a thick and fine pattern. Note that the third resist layer is removed at the same time by this oxygen-based dry etching. Using such a three-layer resist method,
The resist layer for pattern formation can be thin, and since the resist layer is separated from the substrate, it is less likely to be directly affected by standing waves and other effects from the substrate, so it has excellent dry etching resistance during substrate processing. It becomes possible to obtain fine resist patterns with high resolution. A problem with this three-layer resist method is that the process is longer than the conventional method. A two-layer resist method has also been proposed that simplifies the process by creating a two-layer structure by omitting the intermediate layer in the resist method.

However, there are only a few resists that are used as an upper layer for the two-layer resist method that develops sufficient sensitivity and resolution for each exposure source, and conventional resists, exposure methods, and development methods can be applied as is. 3 resists are more useful at this stage.

[Problems to be Solved by the Invention] As the intermediate layer of the three-layer resist, a material having sufficient oxygen-based dry etching resistance, such as an inorganic material such as S++S 1021AI, is used as it serves as a mask during processing of the first layer. There is. As a method for forming this intermediate layer, generally any one of a CVD method, a sputtering method, and a vapor deposition method is used. However, recently, polyorganosiloxane (commonly known as silicone resin) or 51o472 coating liquid (commonly known as spin-on Glass: 5OG) has come to be used as the above-mentioned intermediate layer. This is because the spin code method takes an extremely short formation time and can be performed with simple operations compared to the CVD method, sputtering method, and vapor deposition method. As the above-mentioned 31Q47a coating liquid, a coating agent containing a silanol compound as a main component has been commercialized, but in order to obtain a completely cured film that does not dissolve when applying the upper layer resist, it is necessary to slowly raise the temperature at a high temperature and compare It requires heat treatment for a relatively long time, and strict control of conditions during heat treatment is required. If heat treatment is performed outside the specified conditions, a completely cured film may not be formed or cracks may appear in the film. In addition, since the curing reaction is a condensation reaction that is sensitive to moisture, it tends to change over time, and has the disadvantage that it may harden at the tip of the spin cord nozzle or gel during long-term storage. was.

On the other hand, the silicone resin is
0. This product has the general formula: %Formula%) (wherein R is m groups selected from the group consisting of -valent hydrocarbon groups, hydrogen, hydroxyl groups, and alkoxy groups, which may be the same or different) , -+n”p+q=1, score〉
0, +1. p, Q≧O, and I/Q≦1 ((however, q≠
0)) or ■/p≦0.3 ((however, p≠0))
It is a polyorganosiloxane represented by (and q are not O at the same time) and has a very high heat softening temperature, so the film surface is not sticky and a film with excellent heat resistance can be formed. Furthermore, since the molecule contains many silicon atoms, it has extremely excellent resistance to oxygen-based dry etching. Furthermore, it has extremely superior storage stability compared to condensation curing type materials such as the above-mentioned SOG. Therefore, there is no problem in systems where only solvents with low dissolving power for polyorganosiloxane compounds are used, such as commonly used photoresists, where the solvent is cellosolve or alcohol-based and the developer is aqueous. Because of its versatility, it is attracting attention as an excellent intermediate layer material. However, since it is a non-curing type, it has the advantage that it can be easily removed using a solvent, but on the other hand, a ketone-based or aromatic-based solvent is used as a solvent or developer, especially in the case of EB resist. If the upper resist layer is coated, the intermediate layer may dissolve when the upper resist layer is applied, a mixing layer may be formed at the interface with the upper layer, or the intermediate layer may dissolve when the upper resist layer is developed, so it cannot be used with confidence. The problem remained that there was no such thing.

[Problems to be Solved by the Invention] Therefore, the purpose of the present invention is to be able to form a cured film with a uniform thickness without cracks using the spin code method and short-time heat treatment, and to prevent dissolution and mixing during application of the upper layer resist. To provide a polyorganosiloxane composition for an intermediate layer of a three-layer resist, which does not dissolve during layer formation and upper layer resist development, has excellent resistance to oxygen-based dry etching, and has little change over time and excellent storage stability. be.

Furthermore, another object of the present invention is to use 3F! using the above-mentioned intermediate layer material! An object of the present invention is to provide a method of forming a highly accurate pattern on a substrate using a resist.

[Means for Solving the Problems and Their Effects] The above object is to produce a polyorganosiloxane which has at least two aliphatic unsaturated groups bonded to silicon atoms in its molecule and has a softening temperature higher than room temperature and is soluble in organic solvents. and a catalytic amount of an organic peroxide, a thermosetting polyorganosiloxane composition for a three-layer resist intermediate layer, and a thermosetting polyorganosiloxane composition for forming a pattern on a substrate as an intermediate layer in a three-layer resist method. This is achieved by using organosiloxane compositions.

First, in the thermosetting polyorganosiloxane composition for a three-layer resist intermediate layer of the present invention, the polyorganosiloxane as the component (A) is a base polymer. at least 2 in the molecule
It is necessary to have an aliphatic unsaturated group bonded to silicon atoms, and secondly, in order for the surface of the spin cord film to be non-sticky and to have a uniform thickness, the softening temperature must be higher than room temperature. is necessary. When the softening temperature is higher than room temperature, room temperature means a temperature in the range of about 10 to 40'C, but it goes without saying that the temperature needs to be higher than the atmosphere during the pattern forming operation. Aliphatic unsaturated groups are recombined by radicals generated by thermal decomposition of the organic peroxide contained as a crosslinking agent.
Any structure that can cause a reaction such as quantification or chain polymerization may be used, for example, CH2:CH-CH2=C
H (CH2), - (where n = 1.2, 3, 4), cyclohexenyl group-containing group, CHR, = CR2COO (C
H2), -(where R+ is H or C6H6, R2 is H
or CH3, m=1.2.3.4).

The polyorganosiloxane of component (A) may have a monovalent hydrocarbon group other than the above aliphatic unsaturated group, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, a pentyl group, Examples include phenyl group, tolyl group, and xylyl group, but ease of synthesis, storage stability,
From the viewpoint of heat resistance and oxygen-based dry etching resistance, a methyl group or a phenyl group is preferable.

In addition, all R used as an abbreviation in the following text shall mean a monovalent hydrocarbon group. The softening temperature of the polyorganosiloxane component (A) is higher than room temperature, and room temperature here means a range of approximately 10 to 40°C. A typical example of a polyorganosiloxane that is soluble in organic solvents and has a high softening temperature is the general formula: [R510272]
Examples include polyorganosilsesquioxanes having a structural unit represented by the following as a basic skeleton and polyorganosiloxanes having a structural unit represented by the formula: [5102] as a basic skeleton or in the skeleton.

Polyorganosilsesquioxane has no terminals,
Even if it is a so-called cage type polysilsesquioxane,
It may be a so-called ladder type polysiloxane having a group represented by the general formula: [XOl, 2 (here, X is R or Ra5i) at the end, or The general formula: [R25i
those in which the structural unit represented by O] is partially introduced,
SIY group as a hydrolyzed condensation residue (where Y is OH,
OR or C1) may be included, but in order for the softening temperature to be higher than room temperature, the molecular weight must be higher than a certain level, or the R in the [R3l0372] structural unit must contain many aromatic groups. It is necessary to

On the other hand, as a polyorganosiloxane having a softening temperature in its skeleton and having a structural unit represented by the general formula: [:5tOa, □, for example, the general formula = [R351012
] a [5102] b T: Indicated;
81Oh721 partially introduced structural unit, and SiY group as a hydrolyzed condensation residue (here, Y
may contain OH10R or CI), but in order for the softening temperature to be higher than room temperature, the molecular weight must be higher than a certain level, or the R in the [R3S lo 12] structural unit must contain an aromatic group. Furthermore, the molar ratio of a to b in the above general formula is 0.25 to 1.5, that is, the H content of the [Sl○2 costructural unit in one molecule is 40 It is desirable that the content be in the range of ~80 mol%. If this molar ratio is less than 0.25, the molecular weight will become too high during synthesis, or it will be difficult to gel and obtain a product soluble in organic solvents in good yield. Because it is difficult to increase the molecular weight, it is only possible to obtain a liquid form at room temperature. This molar ratio is preferably within the range of 0.3 to 1.2 in order to be able to synthesize a material having a softening temperature higher than room temperature with good yield.

It is known that the oxygen dry etching resistance of polyorganosiloxanes or silicon-containing polymers is correlated with the silicon atom content in the polymer (for example,
Sem1con, 11orld.

19811i(1), p, 59P, 59-p, 65,
Polymer, 1988. Volume 37 (Ili), P
, 4GO~p, 4G3, J, Electroche
LSoc, 1983, vol. 130. p, 1
9G2, etc.), and in order to function as a sufficient mask when etching and sowing the underlying breeding resist, such as polyimide, in addition to being heat resistant, it must contain at least 10% by weight of silicon atoms. On the other hand, on the other hand, whether the breeding group contained in the polymer is easily detached or not,
It is believed in principle that the lower the content, the better. Therefore, as mentioned above, in the molecular skeleton the general formula:
Introducing structural units represented by [:R8I○372co and/or [Sio2co] is necessary to increase the softening temperature of polyorganosiloxane, and as a result, R contained in the molecule The proportion of groups is [R2510
Since it is smaller than a co-structured material, its resistance to oxygen-based dry etching is correspondingly improved, and it functions as a three-layer resist intermediate layer material superior to ordinary polyorganosiloxane.

The aliphatic unsaturated groups, which must exist at least two times in one molecule, may be contained as any R in these polyorganosiloxanes, but the aliphatic unsaturated groups contained in one molecule If the ratio of the groups is too low, the curability of the composition of the present invention as a whole may deteriorate, the crosslinking density of the cured film may become low, and the adhesion to the upper resist layer during coating or development may become poor. In order to have sufficient curing reactivity and adhesion, it is desirable that one molecule contains at least 10 mol % of aliphatic unsaturated groups.

Cholera polyorganosiloxane can be synthesized by known methods. That is, one to four types of triorganochlorosilane, diorganodichlorosilane, organotrichlorosilane, and tetrachlorosilane corresponding to each structural unit; or triorganoalkoxysilane, diorganodialkoxysilane, organotrialkoxysilane, and tetrachlorosilane; It is relatively easily synthesized by hydrolyzing and condensing one to four alkoxysilanes under acidic or basic conditions. Polyorganosiloxane produced by such a condensation polymerization reaction is often obtained as a mixture of polyorganosiloxanes with a relatively wide molecular weight range, but in addition to having a low softening temperature, the low molecular weight components do not reach the surface of the cured film. Because it tends to ooze out and reduce the adhesion to the upper resist,
For example, it is desirable to remove it by extraction or reprecipitation purification with a solvent that has the ability to dissolve only low-molecular-weight polyorganosiloxanes, such as methanol or acetone.

Next, the organic peroxide which is component (B) acts as a crosslinking agent for thermosetting the polyorganosiloxane which is component (A). Specific examples include ketone peroxides such as methyl ethyl ketone peroxide and methyl cyclohexane peroxide, diacyl peroxides such as benzoyl peroxide and acetyl peroxide, hydroperoxides such as t-butyl hydroperoxide, dicumyl Peroxide, dialkyl peroxides such as dibutyl peroxide, peroxyketals such as dibutylperoxytrimethylcyclohexane, alkyl peresters such as dibutylperoxybenzoate and dibutylperoxyazelate, butylperoxyisopropyl carbonate, etc. Examples include percarbonates. Among these, dicumyl peroxide, dibutyl peroxide, and dibutyl peroxybenzoate are particularly preferred from the viewpoint of reactivity, stability, and compatibility with polyorganosiloxane and solvent.

Component (B) is preferably added in an amount of 1 to 20% by weight relative to component (A).

The curing time depends on the curing temperature, but for use in the lithography process of semiconductor manufacturing, the curing time is 180°C.
It is desirable to cure at a temperature below and in a short time. It is desirable to cure within 120 minutes at 120″C, and within 30 minutes at 180°C.

The polyorganosiloxane composition of the present invention is usually used by dissolving a predetermined amount in an organic solvent so that a film can be formed by the spin foot method. The amount of dissolution may be determined as appropriate depending on the required film thickness. The organic solvent may be selected depending on the influence on the underlying resist and the coating characteristics under each condition. Since the polyorganosiloxane used in the present invention generally has an organic group, it has excellent solubility in organic solvents compared to silicic acid, etc., and has a wide range of solvent selection.

In addition, the organic solvent should have a boiling point of 180°C or less, preferably 16°C or less, so that it can be easily removed by baking after application.
It is desirable to select one with a temperature below 0°C. Specifically, heftane, octane, xylene, propatool, imbutanol, amyl alcohol, nclohexanone,
Examples include methyl isobutyl ketone, diisobutyl ketone, butyl acetate, isoamyl acetate, and ethyl cellosolve acetate.

Incidentally, the polyorganosiloxane composition of the present invention may contain small amounts of dyes, pigments, surfactants, adhesion promoters, heat resistant agents, etc., if necessary.

Next, a pattern forming method using a three-layer resist using the polyorganosiloxane composition as an intermediate layer, which is the second invention of the present application, will be described. To do this, a lower resist layer made of an organic polymeric material, an intermediate layer made of a cured product of the polyorganosiloxane composition, and an upper resist layer made of an madder molecular material that crosslinks or decomposes when irradiated with radiation are placed on the substrate to be processed. After forming a desired pattern on the upper resist layer by exposing and developing the upper resist layer, the intermediate layer and the lower resist layer are sequentially etched, and then the substrate is etched. A preferred embodiment of this patterning method is as follows. First, a lower resist layer is spin-coded onto a semiconductor substrate to a thickness of usually 1 to 2 μm, and then heated. Next, as an intermediate layer, the above polyorganosiloxane composition was applied in an amount of 0.15 to 0.
．． After spin-coding to a thickness of about 4 μm,
A heat treatment at 80° C. for about 120 to 30 minutes completely removes the spin cord solvent and at the same time forms a cured film. Next, an arbitrary resist is spin-coded as a shoe resist under predetermined conditions, heat-treated, and then exposed and developed to obtain an upper resist pattern. At this time, depending on the fences of the upper layer resist, the adhesion with the surface of the cured polyorganosiloxane film of the intermediate layer may be compromised, resulting in non-uniform film thickness when applying the upper layer resist or peeling of the resist pattern during development. . Such a case can be solved by treating the surface of the intermediate layer with oxygen plasma or 03 for a very short time after coating or heat curing the intermediate layer.

Next, the intermediate layer is etched by anisotropic active ion etching (RIE) using a gas containing F atoms, usually CF a, using the previously formed pattern of the upper resist layer as a mask. Next, the lower layer is usually etched by RIE using an oxygen-based gas, and the upper resist pattern is transferred to the lower layer. Thereafter, the semiconductor substrate is processed by any method using the obtained lower resist pattern as a mask. Here, the lower resist material of the three-layer resist is not particularly limited as long as it is a bred polymer that can form a thick film, has excellent dry etching resistance, heat resistance, and planarization properties, and can be processed by oxygen-based RrE. , novolak resin and polyimide resin. Further, the lower resist material may contain a light absorber in order to prevent adverse effects caused by reflection of irradiated light on the substrate during upper resist patterning.

In addition, the upper layer material of the three-layer resist is UV resist,
There are EB resists, electron beam resists, X-ray resists, ion beam resists, etc.

In addition, if the substrate to be processed is an organic material or aluminum, etc., the substrate can be processed with precision using a two-layer structure using the polyorganosiloxane composition of the present invention as a lower layer resist, without the need for special underwear. It can be processed well.

When processing aluminum, RI using chlorine gas
It is effective to do E.

In addition, since the polyorganosiloxane composition of the present invention has excellent dry etching resistance and heat resistance as described above, it can be used in other resist processes such as T, 15
hli, T., Matsuda, K., Harada,
85 Sympo, onVLSI Technology
It can also be effectively used as a mask material in the 5IEL method proposed in , Digest, P, 7G (1985).

[Example] The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples in any way.

Synthesis Example 1 While vigorously stirring a solution consisting of toluene/alcohol/water, a toluene solution in which a small amount of hydroquinone was added to dimethyldichlorosilane and γ-tacryloxypropyltrichlorosilane was added dropwise to hydrolyze the solution, and then toluene was added. The layer was thoroughly washed with water, dehydrated and filtered. A solid acid catalyst and hexamethyldinoxane were added to this filtrate.
The reaction was carried out at 0°C for 5 hours. After cooling, the reaction solution was poured into methanol to form a polyorganosiloxane (base polymer A) having methacrylic groups as curable reactive groups.
) was synthesized.

The obtained polymer had a methacryloxypropyl group content of 65.7% by weight, a Si content of 17.1% by weight, a weight average molecular weight of 21,000°, and a softening temperature of about 70°C.

Synthesis Example 2 While vigorously stirring a solution consisting of toluene/alcohol/water, phenyltrichlorosilane was added dropwise to the solution for hydrolysis, and the toluene layer was thoroughly washed with water and then dehydrated. γ-methacryloxypropyldimethylchlorosilane was added to this toluene filtrate and reacted at 80 to 100°C for 8 hours.

This reaction filtrate was neutralized and filtered, and then poured into methanol to synthesize a ladder-type phenylpolysiloxane whose terminal was γ-methacryloxypropyldimethylsiloxylated (base polymer B).

The obtained polymer had a γ-methacryloxypropyl group content of 9.96% by weight, a Si content of 20.6% by weight, a weight average molecular weight of 5100, and a softening temperature of about 230°C.

Synthesis Example 3 Perform the same operation as in Synthesis Example 2 using a mixture of methyltrichlorosilane and 5-hexenyltrichlorosilane instead of phenyltrichlorosilane, and using trimethylchlorosilane instead of γ-methacryloxypropyldimethylchlorosilane, A polyorganosiloxane (base polymer C) having a hexenyl group as a curable reactive group was obtained.

The resulting polymer had a content of 5-hexenyl groups of 46.
4% by weight, the S1 content was 25.9% by weight, the weight average molecular weight was 105001, and the softening temperature was about 185°C.

Synthesis Example 4 Dilute hydrochloric acid was dropped into a solution consisting of alcohol/toluene/trimethylchlorosilane/S-hexenyldimethylchlorosilane/tetrachlorosilane under stirring with heating, and 5
After heating under reflux for an hour, the toluene layer was thoroughly washed with water. This toluene solution was dehydrated by azeotropy, hexamethyldisilazane was added, and the mixture was refluxed under heating for 4 hours.
By pouring the cooled toluene solution into methanol, a polyorganosiloxane having [S+○2 co-units as a basic skeleton was synthesized (base polymer D).

The obtained polymer has an average compositional formula of [:(CH3)*S
iO+z2koi,+s[(CHs)2(CH2=C
H(CH2)4)S10t72koQlTro5IO2ko4
．． It is expressed as , Si content is 33.4% by weight, [Si○
2 content is 64.5 mol%, molecular weight is 450 on weight average
001 Softening temperature was 300°C or higher.

Synthesis Example 5 While stirring a solution consisting of water/salt ftl/alcohol/toluene/hexamethyldisiloxane at 80 to 100°C, a mixture of tetraethoxysilane and γ-methacryloxypropyltrichlorosilane was dropped and heated for 8 hours. After refluxing, the toluene layer was thoroughly washed with water. This toluene solution was dehydrated by azeotropy, hexamethyldisilazane was added, and the mixture was heated under reflux for 4 hours.The cooled reaction solution was poured into methanol to form the [5j02:] unit as a basic skeleton and harden. A polyorganosiloxane whose sexually reactive group is a methacrylic group was synthesized (base polymer E).
.

The obtained polymer has an average compositional formula of [(CH3)5S
iO+72]a, s+[CH2= C(CH3)CO
○(CH2)3S 103/2koθ, s-[S +04
・It is expressed as 2 1.1 and the 1Si content is 39.9% by weight.
The [Sl○4/2] content was 66.2 mol%, the weight average molecular weight was 79,000, and the softening temperature was 300°C or higher.

Example 1 1 each of base polymers A to E synthesized in Synthesis Examples 1 to 5 above
Solutions a to e were prepared by dissolving 00 parts by weight of dibutyl peroxide and 5 parts by weight of dibutyl peroxide in n-octane to form a 15% by weight solution.

Each solution was spin-coded onto a Si wafer, 170″
When heated for 20 minutes on a C hot plate, a film of uniform thickness with no cracks was formed in each case. When this wafer was immersed in n-heptane, MIBK, and xylene, each film was completely cured without being attacked by any of the solvents.

In addition, exactly the same results were obtained in the case of MIBK in which dibutyl peroxybenzoate was used instead of dibutyl peroxide and n-octane was used.

Comparative Example 1 An n-octane solution was prepared in exactly the same manner as in Example 1 except that dibutyl peroxide was not added, and when it was spin-corded and heated, a film of uniform thickness with no cracks was obtained in both cases. Been formed. However, when this wafer was immersed in n-hebutane, MIBK, and xylene, all of the films were completely dissolved.

Example 2 When RIE was performed on the Si wafer having the hardened film of Example 1 under the conditions of high frequency power of 150 W, oxygen gas flow rate of 20 SCCM, and gas pressure of 2 Pa, the rate of decrease in film thickness (etching rate) for all of the hardened films was shown. was 40/min or less on average over 5 minutes. On the other hand, a commercially available novolac resin resist under the same conditions was
The etching rate of the film formed by heating for 15 minutes at 'C is 10
00/min or more. Therefore, it can be judged that each cured film in Example 1 has sufficient oxygen etching resistance.

Example 3 0FPR-8 manufactured by Tokyo Ohka Co., Ltd. was used as a lower layer resist on a silicon substrate on which a 0.5 μm thick aluminum thin film was deposited.
00 was spin-neated to a thickness of 2 μm and heat-treated at 250° C. for 5 minutes.

Next, as an intermediate layer, 0.2% of the solution a prepared in Example 1 was added.
It was spin-coded to a thickness of μm and heated on a hot plate at 170°C for 20 minutes. Thereafter, FBM-G, which is an electron beam positive type resist, was spin-coded to a thickness of 0.5 μm as an upper layer resist, and subjected to electron beam irradiation and development treatment to form a desired upper layer resist pattern.

Next, RIE using CF4 + 25% H2 mixed gas (
Using the upper resist pattern as a mask, the intermediate layer was etched using the upper resist pattern as a mask. Next, switch the gas to oxygen, 150 W120
Under conditions of S CC'M and 2 Pa, the lower layer was etched using the intermediate layer pattern as a mask. Next, aluminum thin film 300W1 CC1a gas 50S
After etching with CCM125Pa gas plasma, 100 WlCF* + 5% oxygen mixed gas, 1
The intermediate layer was removed by plasma etching under the conditions of 50 SCCM and 110 Pa, and finally the lower layer was ashed using oxygen plasma of 200 W and 150 Pa, thereby obtaining an aluminum thin film pattern with a width of 0.4 μm on the substrate.

Note that similar results were obtained when solutions S, c, d, and e prepared in Example 1 were used instead of solution a used here as the Zhongran layer.

Comparative Example 2 In Example 3, when each solution used in Comparative Example 1 was used instead of solution a as the intermediate layer, a mixing layer was formed when FBM-G, which is the upper layer resist, was spin coded. Alternatively, the desired upper resist pattern could not be obtained because the intermediate layer was dissolved during development after exposure.

Example 4 A photoresist AZ-1350Jt manufactured by Sibley Co., Ltd., which is a composition of cresol formaldehyde novolac resin, was spin-coded to a thickness of 1 μm as a lower layer resist on a silicone substrate on which polycrystalline silicon was deposited with a thickness of 0.3 μm. , heat treatment was performed at 150° C. for 30 minutes in a nitrogen atmosphere.

Next, as an intermediate layer, 0.2% of the solution a prepared in Example 1 was added.
It was spin-coded to a thickness of μm and heated on a hot plate at 170°C for 20 minutes. Thereafter, AZ-1350J was spin-coded to a thickness of 1 μm as an upper layer resist, exposed to ultraviolet light at 438 nm, and developed to form a desired upper layer resist pattern. Next, in the same manner as in Example 3, the middle layer and lower layer were coated. Continued item, 500W1 C012F2 gas 25SCCM, 1
Polycrystalline silicon was etched under conditions of 2 Pa. Thereafter, the lower layer and intermediate layer were removed by heating to 100°C and using a too-)chlorobenzene-tetrachloroethylene mixture to obtain a polycrystalline silicon pattern with a width of 1.0 μm on the substrate.

Note that similar results were obtained when solutions S, C+ d, and e prepared in Example 1 were used as the intermediate layer instead of solution a used here.

[Effects of the Invention] The thermosetting polyorganosiloxane composition for the three-layer resist intermediate layer of the present invention does not have the problems of dissolution during coating of the upper resist layer, dissolution during mixing layer formation, and dissolution during development of the upper resist layer, and does not have the problems of dissolution during coating of the upper resist layer and dissolution during the development of the upper resist layer, and does not require the conventional condensation process. Unlike molds, the coating can be cured with a short heat treatment, and almost no by-products are generated during the curing reaction, so a crack-free cured coating can be easily formed. In addition, since it is not affected by moisture in the atmosphere, there is little change over time during use.
It also has excellent storage stability. In addition, as the base polymer in the composition is an organic solvent-soluble polyorganosiloxane with a softening temperature higher than room temperature, the surface will become sticky and dust will not adhere to it, and the film will not have uneven film thickness during film formation. A uniform thin film can be formed by a simple spin-coding method without causing any problems.

In addition, the cured film formed by the composition of the present invention has excellent heat resistance,
Furthermore, since the composition contains many silicon atoms, it has excellent resistance to oxygen-based dry etching during lower layer processing, and by using the composition of the present invention as an intermediate layer material of a 3-layer resist, it is possible to It is possible to reliably form highly accurate submicron patterns.

Claims (1)

[Claims] 1(A) has at least two aliphatic unsaturated groups bonded to silicon atoms in one molecule, and has a softening temperature higher than room temperature;
Thermosetting polyorganosiloxane composition 2 (A) component polyorganosiloxane for a three-layer resist intermediate layer, characterized by comprising an organic solvent soluble polyorganosiloxane and (B) a catalytic amount of an organic peroxide. The polyorganosiloxane composition 3 (A) of the polyorganosiloxane composition according to claim 1, wherein the siloxane is a polyorganosilsesquioxane, has a formula S in the molecule.
Polyorganosiloxane composition 4 according to claim 1, having a structural unit represented by iO_4_/_2 A lower resist layer and an intermediate layer made of an organic polymer material are cross-linked with radiation on a substrate to be processed. Alternatively, an upper resist layer made of a decomposable polymeric material is sequentially laminated, a desired pattern is formed on the upper resist layer by exposing and developing the upper resist layer, and then the intermediate layer and the lower resist layer are sequentially etched. In a three-layer resist method in which a pattern is formed on a substrate by then etching the substrate, the intermediate layer is
A pattern forming method characterized by using the polyorganosiloxane composition according to item 1, 2 or 3.