JPS58168047A - Photosensitive material - Google Patents

Abstract

PURPOSE:To obtain a photosensitive material with high sensitivity and high resolving power to far ultraviolet rays and electron beams and stability to heat, moisture, etc. by using a high polymer compound having halogenated benzoic acid residues or halogenated phenoxycarbonyl groups as a film forming photosensitive component. CONSTITUTION:A photosensitive soln. is prepared by dissolving a high polymer compound having about 500-500,000mol.wt. in a solvent. The compound has 1- 100mol% bonded groups represented by the formula (where each of X, X' and X'' is C, Br or I, Y is carboxyl or hydroxycarbonyl, and l, m and n are numbers satisfying l+m+n=1-5), and the stock polymer includes a copolymer of 20- 90mol% vinyl monomer having a benzene ring such as styrene with other vinyl monomer. By applying the photosensitive soln. to a silicon wafer or the like, a resist film is formed to obtain a photosensitive material for forming a fine pattern used in the manufacture of an integrated circuit by a drawing method with far ultraviolet rays or electron beams.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photosensitive material, and more particularly to a photosensitive material suitable for microfabricated lenost.

In recent years, in the field of microelectronics, as the degree of integration has become larger and more complex, processing precision reaching submicron levels is required, and electron beam lithography has been adopted. The electron beam lithography method has excellent processing accuracy and also functions as a turn generator, so it is used in the production of master masks.

However, at present, the electron beam lithography method has a slow lithography speed, so it is not suitable as a means for producing large quantities of identical strips. Therefore, there is a need for a technology that transfers with high precision from a master mask created by electron beam lithography. 3300-450. Conventional photolin graphs using OA's relatively long wavelength ultraviolet rays (referred to as near ultraviolet rays) are accompanied by significant diffraction and radiation, resulting in ultraviolet radiation of 1 μm or less.
It is impossible to transfer the turn). For this reason, transfer methods using X-rays or electron beams are also being researched, but no practical device has been developed yet.

By the way, in 1975, KB, J, and Lin were 2000-2.
Ultraviolet rays with relatively short wavelengths (deep ultraviolet rays, Dee
By using pUV (called pUV), submicron
We announced that e-turn transcription is possible (B, J
, Lin 2Deep UV LITHOGRAPH
Y, Journal of Vacuum3cien
ce and Technology, vol, l
2. Jli ('+.

1975, pp 1317-1320+. For this reason, research is progressing rapidly as a technology with high feasibility, and a practical exposure apparatus has already been developed. However, DeepU
■Even with RISOGRAPH 3, sufficient resolution cannot be obtained by using conventional photorenost as is.

B, J, and Lin obtained the above results using polymethyl methacrylate (PMMAI), which is also known as a high-resolution electron beam renost.

be. The aforementioned PMMA is a positive renost. Dee
A practically satisfactory negative resist for pUV lithography has not yet been developed. In microfabrication or depending on the process, it is advantageous to use both a bottom type and a negative type soto, and it is a practical negative type DI/ep.
The development of UV Resost is required.

In general, photosensitive materials for negative tone renosts are made by chemically bonding a crosslinking group to a film-forming substance (mainly a high molecular compound) as a base substance, or by using a crosslinking agent (low molecular compound).
can be prepared by mixing with a film-forming substance.

From this point of view, the present inventors have carried out extensive research and have found a group 1r represented by the general formula (1).

Polymer acupuncture needles with
It exhibits extremely high sensitivity to K, and is highly stable against visible light, heat, moisture, etc., making it extremely suitable as a crosslinkable photosensitizer for negative-tone Deep UV renost. They discovered that it is also effective as a photosensitive component 4) and completed the present invention 1.!
That is, the present invention aims to provide a photosensitive material that can be used as a negative type deep UV resist and an electron beam resist, and has the following gist.

General formula (where x, x /, x // are the same or different! 3 represents a chlorine atom, a bromine atom, yellow represents an iodine atom, Y is a carboxyl group 5 (/') satisfies the condition (representing an integer of 0 or 1 or more). Also,
For the same purpose, the present invention is a photosensitive material characterized by containing a low molecular weight compound having a group represented by the general formula (1) as a photosensitive component and also containing a coating film forming substance.

According to the present invention, it is possible to obtain a deep UV resist and an electron beam renost, particularly a practical negative-tone deep UV renost that is excellent in sensitivity, film formability, adhesion to a substrate, resolution, corrosion resistance, and stability. General formula (
The groups represented by 1) may be the same or different, and may contain one or more groups bonded together. In addition, in the group represented by general formula (1), the 〇-position or/and p-position
Those having a substituent at that position exhibit particularly high sensitivity. The basic substance or film-forming substance used in the present invention includes natural polymer compounds such as cellulose gel, phenol nopolanox resin, polyester resin, polyamide, ll+1
Condensation polymers such as fats or addition polymers such as vinyl polymers σ) could be used. Among these, for vinyl polymers, the type of monomer and the mixing ratio can be selected relatively freely, and it is possible to change the polymerization initiator elf or use a chain transfer agent (generally well-known). It is easy to adjust the degree of polymerization by a method and can be used advantageously. Generally, the physical properties of a polymer can be predicted to some extent from the composition of the monomers constituting it. styrene, a
- Polymers containing a large amount of monomers with benzene nuclei such as methylstyrene, vinyltoluene, vinylnaphthalene, vinylcarbazole, and acenaphthylene have excellent resistance to so-called dry etching such as plasma etching, reactive ion etching, and ion etching. It is well known in the art for this. On the other hand, when the ratio of such benzene nucleus-containing monomer increases, Vζ cracks tend to occur when formed into a thin film, and the adhesion to the substrate tends to deteriorate. Rubber-based polymers such as polycitatsuene tend to swell with organic solvents, making it difficult to obtain resists with high resolution. Furthermore, since resists are often used at high temperatures of 100° C. or higher, it is not preferable to use a resist that contains a large amount of monomer that lowers the softening temperature of the polymer. Sll-1
Furthermore, monomers containing fluorine atoms tend to deteriorate the adhesion of the filter to the substrate. The knowledge described here is well known in the technical field, and from this point of view, the type and ratio of monomers can be selected depending on the purpose.

When bonding a group represented by general formula (1) to a polymer,
At least one kind of monomers constituting the polymer is
It must have a functional group to which the group represented by general formula (1) can be bonded by a chemical method. As such mono-7-, monomers having functional groups such as epoxy groups, hydroquine groups, carboxyl groups, and carboxylic acid halide groups are advantageously used.

In the case of negative tone Lennost, the resolution tends to improve as the molecular weight of the base material decreases, but at the same time the sensitivity decreases in proportion to the molecular weight.

In addition, if the molecular weight is too small, the mechanical strength of the coating film tends to deteriorate, so it is impossible to make the molecular weight of the basic material extremely small. From this point of view, the molecular weight range of the basic substance can be determined, but in the case of the present invention, it is generally used that has a molecular weight of about 500 to 500,000, preferably about 5,000 to 200,000. Used to advantage. As a basic substance, the molecular weight is about 500~
500. ．． When a group represented by the general formula (1) is bonded to a polymer of 000, the amount introduced can be selected within the range of 1 to 100 mol per repeating unit of the polymer, but preferably 2 to 50 mol. selected within the relevant range.

When the amount of the introduced group shown in general formula (1) is less than 2 moles, it is necessary to make the molecular weight of the base substance relatively large.
This is disadvantageous because the scope for obtaining high-resolution Lennost becomes narrower.

The group represented by general formula (1) may be bonded to a monomer in advance, or may be bonded to a polymer by reaction. The reaction method for bonding to the side chain of a polymer or a polymer as shown in the general formula (1) is not particularly limited and may be any of the commonly known methods. By bonding a fatty acid residue to the compound in addition to the group represented by the general formula (1), it is possible to obtain a photosensitive material with even more excellent properties. The effect of fatty acid residues is mainly to improve the resolution of renost by suppressing the swelling of renost during development.
There are many things. The fatty acids used in the present invention are preferably saturated fatty acids and unsaturated fatty acids having 2 to 6 carbon atoms. Examples of such fatty acids are acetic acid,! Examples include lopionic acid, butyric acid, crotonic acid, vinylacetic acid, acrylic acid, and methacrylic acid. The ratio of introduction thereof is preferably 0.2 to 3 fatty acid residues per one group represented by the formula ().

When a low-molecular-weight compound having a group represented by the general formula (11) is used as a photosensitive component, the mixing ratio of the film-forming substance to 1 part of the film-forming substance is lJ, 05 to 1.
It can be selected within the range of 0 parts by weight. When the amount added is less than 0.05 parts by weight, sufficient sensitivity cannot be obtained, and when it exceeds 1.0 parts by weight, it may adversely affect film formability and resolution. The photosensitive component used in the present invention has the general formula (1)
It is a low-molecular compound having 1 or 2 to 5 or more groups represented by, for example, the general formula (wherein,
n HY represents the same flavor as @, and 2 represents a hydrogen atom, an alkyl group, or a lower hydrocarbon chain. ).

Examples of such compounds include 2,4-sochlorobenzoic acid, methyl 2,4-sochlorobenzoate, 0-chlorobenzoic acid ethylene glycolenoester, 0-chlorobenzoic acid pentaerythritol triester, 2,4- Examples include, but are not limited to, sochlorophenol acetate.

The photosensitive material of the present invention forms effective VC renosts with light and electron beams with wavelengths of about 2000-3000, but especially with light with wavelengths of about 2000-2600 (De
Valid for ep UV l vc.

For example, when the photosensitive material of the present invention is used for eep UV renost, the photosensitive material of the present invention is bathed in a suitable solvent such as ethylene glycol monomethyl ether acetate on a substrate such as a silicon wafer. Then, apply it uniformly using a spinner and dry to form a 4-1 μm thick lennost layer. Next, apply a light source that efficiently emits light with a wavelength of about 2000 to 2600, such as a xenon-mercury lamp. A mask using a material that transmits this light, such as an artificial quartz plate, is used as a support.
Exposure through turns. Next, if this is immersed in a developer, such as a mixed solvent of methyl ethyl ketone and ethanol, and the unexposed areas are exposed, it is possible to obtain minute turns that are faithful to the mask. Since the photosensitive material σ) of the present invention is not sensitive to visible light, it can be handled in a bright room. In addition, it is stable against moisture and heat, does not require special care in handling, and has excellent storage stability.

The photosensitive material of the present invention is also useful as a resist for electron beam photolithography 1-. It exhibits a sensitivity of more than 10 microcoulombs/c11 to an electron beam with an accelerating voltage of 10 to 30 KV, and has a lattice shape of 0.3 μm. Turns can be resolved.

Next, the present invention will be explained in more detail from Example 911K. However, the present invention is not limited to these Examples.

Practical example 1 (Synthesis of polymeric compound) Molecule B22 consisting of 85 moles of base material Tojimata methacrylate and 15 moles of glycitul methacrylate. A copolymer of ooo was prepared, and the derivatives shown in Table 1 were attached to the epoxy group in 1O molar bond to the polymer. An example of the reaction used here is as follows.

The aforementioned copolymer 282 and 2,4-duchlorobenzoic acid 12
F was dissolved in 250 ml of methyl ethyl ketone (250 ml/kg), and a catalyst was added to it.
．． 52 was added, and the mixture was heated under reflux for 4 hours while stirring.

After cooling, the reaction solution was poured into inzorobil alcohol and the polymer was recovered, which was dried under reduced pressure at room temperature. A portion of the thus obtained polymer was taken and the amount of unreacted epoxy groups was determined by a conventional method. As a result, the amount of 2,4-duchlorobenzoic acid introduced was 10 moles relative to the polymer.

(Preparation and use of photosensitive number) Next, polymer 20 to which each derivative shown in Table 1 was added was prepared.
2 was dissolved in ethylene glycol monomethyl ether acetate (1OO-) to prepare a photosensitive solution.

This photosensitive solution was applied onto a silicon wafer using a spinner and then baked at 90° C. for 30 minutes to remove the bathing agent and form a resist film with a thickness of 7 μm (7). This resist film was heated at 500W from a distance of 15crn.
After exposure with a xenon-mercury lamp for varying times in stages, it was placed in a bath mixture of methyl ethyl ketone and ethanol for 60 minutes.
The film was immersed for a second and developed, and the sensitivity was evaluated by the reciprocal of the time required for the remaining film thickness to become equal to the coated film thickness, and the results shown in Table 1 were obtained. The relative sensitivities in Table 1 are expressed as 1, with the sensitivity of the base polymer itself used here being 1.

Table 1 Example 2 The same base polymer as used in Example 1 and 2,4-dichlorobenzoic acid were added in proportions of 3 mol and 6 mol'1, respectively.
．． 10 molar bonds were made. The sensitivity of these photosensitive materials obtained in the same manner as in Example 1 was measured in the same manner as in Example 1, and the results shown in Table 2 were obtained.

Table 2 (Note) * Same as Table 1 & 4 above Example 3 A copolymer with a molecular weight of 11,000 consisting of 40 moles of methylene ref and 60 moles of glycitul methacrylate was prepared as the base material, and the same as in Example 1 was prepared. 2,4 in the manner described
- 0.2 dichlorobenzoic acid per repeating unit of the polymer
These six photosensitive materials, which were synthesized from photosensitive materials in which each individual was bonded, exhibited a relative sensitivity of 300 according to the standards shown in Table 1.

Example 4 Same backbone polymer 282.2,4 as used in Example 1
-dichlorobenzoic acid 12t and 3-planoic acid 242 methyl ether) y2
The mixture was seeded at 50 dK, and 0.52 ml of triethylbennolammonium chloride was added thereto, followed by heating and refluxing for 4 hours while stirring.

After cooling, the reaction solution was poured into isozorobyl alcohol to recover the polymer, which was dried under reduced pressure at room temperature. A portion of the polymer obtained in this way was taken, and the composition was calculated by quantifying the amount of chlorine atoms and the amount of unreacted epoxy groups in the polymer. The amounts introduced were 6 mol % and 5 mol %, respectively, relative to the base polymer.

Further, the relative sensitivity of this photosensitive material measured using the same criteria as in Table 1 was 350.

Example 5 The basic substance was 90 mol% of methyl methacrylate and 100 mol% of 2-hydroxyethyl methacrylate, with a molecular weight of 20.
000 copolymer was prepared. This copolymer 109 and 2.47 nochlorobenzoic acid chloride 25f were dissolved in methyl ethyl ketone 50-, and triethyl chloride was added to the solution. raremin 1
After adding 7 cc and stirring at room temperature for 24 hours, the polymer was poured into water at t7 and recovered. This polymer was purified by bathing it in methyl ethyl ketone C, reprecipitating it in isoglozonol, and drying it under reduced pressure at room temperature. Almost no hydroxyl group around 3400 tyn' was observed in the infrared absorbing polymer thus obtained, indicating that the esterification proceeded quantitatively.

A photosensitive solution was prepared by dissolving lOv of this photosensitive material in 50% of ethylene glycol monomethyl ether acetate,
Sensitivity was measured in the same manner as in Example 1.

This photosensitive material has a relative sensitivity of 5 using the same comparison criteria as in the iE1 table.
It showed 00.

Example 6 2.4~Duchlorphenol 259 was soaked in a 5% caustic soda water bath 1140f and cooled on ice. Methacrylic acid chloride 16f was added dropwise to the mixture and stirred for FLIQ minutes, and then the mixture was returned to room temperature and stirred for an additional 30 minutes. The formed crystalline precipitate was collected by filtration, washed with a 1% caustic soda water bath, and then dried under reduced pressure at room temperature. Further, it was recrystallized with ethanol to obtain needle-like crystals of 18.7 F.

The melting point of this crystal was 56-57°C, which corresponded to the melting point of 2,4-dichlorophenyl methacrylate, 56°C. It was also confirmed that the infrared absorption spectrum ( ) was 2,4-dichlorophenyl methacrylate.
．． 69 (20 mol%) and methyl methacrylate8. O
(80 mol) was added to methyl ethyl ketone 10, azobisinzotyronitrile was added, and the mixture was heated to 80° C. with stirring. After 2 hours, 5 grams of methyl ethyl ketone was added, and the mixture was kept at 8°C for 1 hour, cooled, and then poured into inozolopanol to sinter the polymer.

This was bathed in methyl ethyl ketone and reprecipitated with isozolopanol to obtain purified polymers of t o and o t. The molecular weight of this polymerized μ was approximately 30,000.

This polymer 202 was bathed in ethylene glycol monomethyl ether acetate (100) to prepare a photosensitive solution, and the sensitivity was measured in the same manner as in Example 1.

This photosensitive material was negative-tone and had a relative sensitivity of 7o according to the same evaluation criteria as in Table II1.

Example 7 Photosensitive material 20f shown in Table 2 A 2 vζ of Example 2
ethylene glycol monomethyl ether acetate l
Dissolve in 0.2 μm membrane filter
A photosensitive solution was prepared. This photosensitive solution was applied using a spinner onto a silicon substrate having an oxide film of 5,000 Å in thickness, and then baked at 90° C. for 30 minutes to form a resist film with a thickness of 7 μm. Next, a quartz mask pattern was brought into close contact with this resist film, and
After exposure for 6 seconds with a xenon-mercury lamp of W, the volume ratio l:
60 l of methyl ethyl ketone and ethanol mixed bath agent
By immersing it for a second to develop it, and then washing it with isozolosenol, it was possible to accurately obtain a transferred image of a turn on a 0.5 μm mask.

Next, the silicon substrate on which the Renost i+turn was formed was baked at 120° C. for 30 minutes, and then placed on the cathode side O of a parallel plate type plasma etching apparatus, and the silicon oxide film was etched under the following conditions.

Renost shows sufficient dry etching resistance and can be etched faithfully to the mask pattern. I was able to get a turn.

Etching conditions: Etching gas CF4+ (20%) Gas pressure 0.02 Torr Gas flow rate 70SCCM RF power 200W Example 8 Dissolve the photosensitive material 2 of Example 9'll 3 in ethylene glycol monomethyl ether acetate 100- A photosensitive solution prepared by filtering through a 0.2 μm membrane filter was applied onto a silicon wafer with a 5000A oxide film using a spinner, and heated at 90°C for 30 minutes.
Baking was performed for a minute to form a Lenost film with a thickness of 7 μm. A quartz mask was placed in close contact with this Renost film, and a 500W
After exposure to a xenon-mercury lamp for 8 seconds, the mixture was developed with a bath mixture of inozolopanol and methyl ethyl ketone in a 7:3 volume ratio, and rinsed with n-hebutane.
We were able to transfer micrometer patterns with high precision. Next, the silicon wafer with the mother turns formed thereon was heated to 150°C.
After baking for 30 minutes at 30°C and then immersing it in a 30°C hydrofluoric acid buffer bath (g + 401 hydrofluoric acid I N + 6 parts of 401 ammonium fluoride aqueous solution) for 4 minutes and etching, there was no seepage or peeling of the renost. I was able to obtain an etching noso turn that was faithful to the mask/mother turn.

Example 9 The photosensitive material 2Of obtained in Example 4 was treated with ethylene glycol monomethyl ether acetate 100W1t [soaked,
A photosensitive solution prepared by filtering through a 0.2 μm membrane filter was applied to a silicon wafer using a spinner and baked at 90 C for 30 minutes to form a resist film with a thickness of 7 μm. A quartz mask was brought into close contact with this resist film, and after exposure for 6 seconds with a 500 W xenon-mercury lamp, it was developed in the same manner as in Example 7 with a mixed solvent of methyl ethyl ketone and ethanol, and then washed with isozolo-zonol. The swelling of the Lennost image during development was very small, and an extremely accurate transfer pattern was obtained.

In fact, scary example 10 2,4-dichlorobenzoic acid 2.72 as a low-molecular compound with a group represented by general formula (1) and 85 mol of methyl ref as a film-forming substance and 15 mol of glycidyl methacrylate as a film-forming substance. A photosensitive solution was prepared by bathing copolymer 20F with a molecular weight of 22,000 consisting of the following in 100% of ethylene glycol monomethyl ether acetate.

As a result of an investigation using the same evaluation method as in the case of implementation, σ
) The relative sensitivity was 4. In addition to these results, Table 3 summarizes the results obtained using another type of low-molecular-weight compound.

Table 3 Example 11 The paste prepared in Example 7 was added to glass soil to a thickness of 7.
Coated on a chrome substrate with a chromium layer of 0.00 and heated at 90℃
A resist film having a thickness of 0.6 μm was formed by baking for 30 minutes.

This substrate was placed in a vacuum, and after sweeping the Lennost surface with an electron beam with an acceleration voltage of 27 KV, it was taken out, developed in a mixed bath of methyl ethyl ketone and ethanol in the same manner as in Example 7, and then washed with isopro7ol. However, a Lennost image was obtained in the area irradiated with the electron beam.

This Lennost image was able to resolve gratings/turns of 0.3 μm. Further, the amount of charge irradiated at this time was 8 microcoulombs per square centimeter, and the thickness of the resist film after development was 0.35 μm.

Reference Example [In the general formula (1), Y is neither a carboxyl group nor an oxycarbonyl group] Chlorstyrene (a mixture of 65 parts of 0-chlorostyrene and 35 parts of p-chlorostyrene) is combined with a compound having a molecular weight of '20.
000 polychlorostyrene was obtained. This polymer 2O
f Seedlings are grown in 100m/100m of wochlorobenzene, (), 2μ
It was filtered with a membrane filter of 1.0 m.

Next, this polymer gfiY was applied onto a silicon wafer using a spinner, and then baked at 9 oc for 30 minutes to form a 7 μm thick polymer film. This polymer membrane was applied to conduction 1 (il + 1) and 5 ocw
After exposure with a xenon-mercury lamp of
The relative sensitivity (), which is the same as in Table 1, was 9 or less.

Claims (1)

[Scope of Claims] (1) Represents any of the general formulas (in the formula, x, x', x'' are the same or different! 7 is a chlorine atom, a bromine atom, and an iodine atom), and Y is a carboquine m , n are the same or different and 1
≦ represents an integer of 0 or 1 or more that satisfies the condition of 10m10n≦5. ) A photosensitive material comprising a polymeric compound having a group exhibiting the above properties as a film-forming photosensitive component. (2) The group represented by the general formula (11) is a 0-chlorobenzoic acid residue, p-chlorobenzoic acid residue, 2゜4-nochlorobenzoic acid residue, 2,6-dichlorobenzoic acid residue, 0 −
The photosensitive material according to claim (1), which is either a chlorophenoxycarbonyl group, a p-chlorophenoxycarbonyl group, a 214-dichlorophenoxycarbonyl group, or a 2,6-nochlorophenoxycarbonyl group (3) The photosensitive component is a polymer having a molecular weight of about 500 to 500,000, and is a polymer compound having 1 to 100 molar groups represented by the general formula (1).
) Photosensitive materials. (41i optical component) A vinyl monomer having a benzene nucleus such as styrene, vinyltoluene, a-methylstyrene, vinylnaphthalene, vinylcarbazole, acenaphthylene (2() to 90 mol) and one or more other vinyl monomers. A copolymer composed of monomers with a molecular weight of about 5,000 to 200,000 and having the general formula (1
) A photosensitive material falling within the range (1), which is a polymeric compound having 2 to 50 moles of groups represented by the formula (O). (5) The photosensitive component has one group represented by the general formula (1), C2 to VC. Claim (1), which is a polymer compound having 0.2 to 3 fatty acid residues bonded together (
7') Photosensitive material. (Represents any of the 61 general formulas, Y is carboquine m, and n is the same or different and represents an integer of 0 or 1 or more satisfying the condition l≦L+m+n≦5.) 1. A photosensitive material, characterized in that it contains a low-molecular-weight compound as a photosensitive component, and also contains a film-forming substance. (7) The group represented by general formula (1) is 0~chlorobenzoic acid residue, p-chlorobenzoic acid residue, 2゜4~sochlorobenzoic acid residue, 2,6-dichlorobenzoic acid residue, Claim (6) Which is a 0-chlorophenoxycarbonyl group, a p-chlorophenoxycarbonyl group, a 2,4-dichlorophenoxysulfonyl group, or a 2,6-dichlorophenoquine carbonyl group. photosensitive material.