JP2538118B2 - Negative radiation-sensitive resist composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel negative-type radiation-sensitive resist composition, and more specifically, to a resolution and resist pattern profile suitable for microfabrication in the field of manufacturing semiconductor devices. The present invention relates to a negative-type radiation-sensitive resist composition which is excellent in shape and has small radiation dose dependency.

2. Description of the Related Art In recent years, the progress of high density and high integration in semiconductor devices has been remarkable, and the resolution in the fine processing technology has been demanded up to the submicron region. Also, with respect to the lithography technology, which is the mainstream in the field of manufacturing semiconductor devices, fine processing of 0.5 μm or less is required, and in order to meet this, Deep UV, i-line and g-line which are short-wavelength ultraviolet rays, etc. It is proposed to use a light source that emits a wavelength of 200 to 500 nm for exposure. In recent years, an excimer laser has been developed and a KrF laser (wavelength: 248 nm) has been used. In addition, the development of resists sensitive to electron beams and X-rays is also underway.

Research on negative resist compositions compatible with radiation as described above has also been actively conducted, for example, Deep
A composition composed of a phenol novolak resin and a bisazide compound as one sensitive to UV, i-rays and g-rays, and a composition composed of a mixture of chloromethylated polystyrene or polyvinylphenol and an aromatic bisazide compound as one sensitive to excimer laser ( JP-B-62-8777), a thermosetting resin and a photoacid generator which are sensitive to excimer laser, Deep UV and X-ray.
A composition comprising a halogenated organic compound that absorbs actinic radiation in the range of 0 to 299 nm (JP-A-62-16405), and a composition sensitive to electron rays, such as polymethylmethacrylate (JP-B-45-30225). No.), polyglycidyl methacrylate ["Journal of Electrochemical Society (JECS)" Vol. 118, p. 669 (1
971)] Chloromethylated polystyrene (JP-A-57-176)
No. 034) and the like are known.

However, in the resist composition for this,
The resist pattern obtained therefrom has a drawback in that the cross-sectional shape is apt to sew, the profile shape is poor, and high resolution cannot be obtained. Furthermore, since these resist compositions have a large dimensional change amount of the resist pattern with respect to changes in the irradiation amount of radiation such as Deep UV, i-ray, g-line, excimer laser, electron beam, and X-ray, a fine resist pattern is formed. At this time, there is also a problem that a blank portion of a space between resist patterns is bad and it is difficult to form a fine line-and-space resist pattern.

Thus, Deep UV, i-line, g-line, excimer laser, electron beam,
As for a negative resist used in lithography using X-rays or the like, a practical resist has not yet been obtained.

Therefore, in the field of semiconductor device manufacturing, the resolution and profile shape are excellent, and the dimensional change amount of the resist pattern with respect to the change in the irradiation amount of the various radiations is small, and a fine line-and-space resist pattern is formed. There is a strong demand for development of a negative-working radiation sensitive resist composition.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In response to such a demand, the present invention is sensitive to various radiations, has high resolution and excellent profile shape, and has a fine line-and-space resist pattern with a small dimensional change amount. It was made for the purpose of providing a negative-type radiation-sensitive resist composition capable of forming a film.

Means for Solving the Problems As a result of intensive studies to develop a negative-type radiation-sensitive resist composition having the above-mentioned preferable properties, the present inventors have found that a specific cresol novolac resin, a specific triazine compound and an alkoxy compound. It has been found that a composition containing a methylated urea resin can achieve the object, and based on this finding, the present invention has been completed.

That is, the present invention provides (A) m-cresol 30% by weight.
Cresol novolac resin obtained from a phenolic compound containing the above, (B) general formula (I) (Z in the formula is R ¹ and R ² are an alkyl group having 1 to 5 carbon atoms, R ³ and
R ⁴ are each a hydrogen atom, a hydroxyl group or a carboxyl group, which may be the same or different from each other), and (C) an alkoxymethylated urea resin. The present invention provides a negative type radiation sensitive resist composition containing the same.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, the cresol novolac resin used as the component (A) is a phenolic compound containing 30% by weight or more of m-cresol, preferably m-cresol.
A mixed phenolic compound containing 30% by weight or more of cresol and at least one selected from p-cresol, 2,5-xylenol and 3,5-xylenol as the remaining component, more preferably It is obtained from a mixed phenolic compound containing 55 to 75% by weight of m-cresol and 45 to 25% by weight of at least one selected from p-cresol and 3,5-xylenol. .

By using such a cresol novolac resin, a resist pattern having an excellent profile shape can be formed.

The cresol novolak resin is, for example, m-cresol, p-cresol, 2,5-xylenol and 3,5-
It can be produced by subjecting a mixed phenolic compound containing at least one selected from xylenol in predetermined proportions to formalin in a condensation reaction in the presence of an acid catalyst.

Among such cresol novolac resins, those having a weight average molecular weight of 2000 to 20000, preferably 3000 to 15000 are practically used.

Specific examples of the triazine compound represented by the general formula (I) used as the component (B) in the composition of the present invention include 2 (p-methoxyphenyl) -4,6-bis (trichloromethyl) -1,3. , 5-Triazine, 2- (p-ethoxyphenyl) -4,6-bis (trichloromethyl)-
1,3,5-triazine, 2- (p-propoxyphenyl)
-4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (p-butoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4 -Methoxynaphthyl) -4,6-bis (trichloromethyl) -1,
3,5-triazine, 2- (4-ethoxynaphthyl) -4,6
-Bis (trichloromethyl) -1,3,5-triazine, 2
-(4-propoxynaphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-butoxynaphthyl) -4,6-bis (trichloromethyl) -1,3,5 −
Triazine, 2- (4-methoxy-6-carboxynaphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxy-6-hydroxynaphthyl) -4,6- Examples thereof include bis (trichloromethyl) -1,3,5-triazine. These triazine compounds may be used alone or in combination of two or more kinds.

The alkoxymethylated urea resin used as the component (C) in the composition of the present invention is obtained by reacting urea with formalin in boiling water to obtain a condensate, which is then reacted with methyl alcohol, ethyl alcohol, propyl alcohol, butyl. It can be prepared by etherifying with a lower alcohol such as alcohol and then cooling the reaction solution to take out the precipitated resin.

Specific examples of the alkoxymethylated urea resin include a methoxymethylated urea resin, an ethoxymethylated urea resin,
Propoxymethylated urea resins, butoxymethylated urea resins, and the like. These may be used alone,
You may use it in combination of 2 or more type.

Regarding the blending ratio of each of the above components in the composition of the present invention, the weight ratio of the cresol novolac resin as the component (A) and the alkoxymethylated urea resin as the component (C) is 60:40.
It is desirable to use it in a ratio of from 95: 5 to 95: 5, preferably from 75:25 to 90:10. If the ratio of the component (A) to the component (C) deviates from the above range, the object of the present invention cannot be achieved, which is not preferable.

Further, the triazine compound as the component (B) is blended in an amount of 0.5 to 10% by weight, preferably 1 to 7% by weight, based on the total amount of the components (A) and (C). If the amount is less than 0.5% by weight, the object of the present invention is not sufficiently achieved, and if it exceeds 10% by weight, the solubility of the resist in an alkaline aqueous solution is deteriorated and the developability is deteriorated, which is not preferable.

The composition of the present invention is usually used in the form of a solution obtained by dissolving the above components in an organic solvent. Examples of the organic solvent used at this time include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate or diethylene glycol monoacetate, or their monomethyl ether, monoethyl ether. , Polypropyl alcohols such as monopropyl ether, monobutyl ether or monophenyl ether and their derivatives; cyclic ethers such as dioxane; and methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, Examples thereof include esters such as ethyl pyruvate. These may be used alone or as a mixture of two or more.

The composition of the present invention may contain additives that are compatible as desired within a range that does not impair the purpose of the present invention, such as an additional resin.
Conventional additives such as plasticizers, stabilizers, surfactants, sensitizers, dyes and the like can be added.

Next, a method of forming a fine pattern using the solution of the negative-type radiation-sensitive resist composition thus prepared will be described. First, a solution of the resist composition on a substrate such as a silicon wafer. Is coated with a spinner and dried to form a radiation sensitive layer, then g
Line, i-line, Deep UV, excimer laser, X-ray selectively irradiates through a mask or electron beam scans and irradiates, then heat treatment is applied, and then, for example, 2 to 10 wt% of tetramethylammonium By developing with an organic alkaline aqueous solution such as hydroxide or choline, the non-irradiated portion is selectively dissolved and removed, and a resist pattern having an excellent profile shape can be formed.

EFFECTS OF THE INVENTION The negative-type radiation-sensitive resist composition of the present invention can form a resist pattern having excellent resolution and profile shape, and since the dimensional change of the resist pattern with respect to the change of the irradiation dose of radiation is small, Since it is difficult for adjacent resist patterns to be bonded to each other in a fine pattern and a good resist pattern can be formed, the resist pattern is particularly preferably used for manufacturing a semiconductor element in which microfabrication is advanced.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 70:30 by weight ratio of m-cresol and p-cresol
4 g of cresol novolac resin (weight average molecular weight 6000) obtained by condensation by a conventional method using an oxalic acid catalyst and 1 g of methoxymethylated urea resin were dissolved in 15 g of ethyl lactate. Then, in this solution, 2- (p-methoxyphenyl) -4, relative to the total amount of cresol novolac resin and methoxymethylated urea resin was added.
Add 6-bis (trichloromethyl) -1,3,5-triazine to 3
A resist solution was obtained by pressurizing and filtering what was added and dissolved at a ratio of wt% using a membrane filter having a pore size of 0.2 μm.

Next, the resist solution thus obtained is left to stand in an atmosphere of hexamethyldisilazane for 7 minutes, spin-coated on a 5-inch silicon wafer surface-treated at 4000 rpm for 20 seconds, and dried on a hot plate at 80 ° C. for 90 seconds. By doing so, a resist layer having a thickness of 1.0 μm was obtained. Then, the obtained resist layer is selectively exposed to i-line by an i-layer reduced projection exposure apparatus LD-5011iA (manufactured by Hitachi Ltd.),
A heat treatment was carried out at 110 ° C. for 90 seconds, and then, immersion in a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 1 minute was carried out to dissolve and remove the non-irradiated portion of i-line to obtain a resist pattern. This resist pattern was a 0.50 μm resist pattern having a good profile shape that was vertically raised from the silicon wafer surface, and its sensitivity was 100 ms. Further, when the appropriate irradiation amount for obtaining a resist pattern of 0.50 μm was set separately and the dimensional change amount of the resist pattern when the set irradiation amount was changed by ± 15% was calculated, it was ± 0.05 μm.

Examples 2 to 23 The composition of the cresol component in the cresol novolac resin, the kind of the alkoxymethylated urea resin, the mixing ratio of the cresol novolac resin and the alkoxymethylated urea resin, the kind and the blending amount of the triazine compound are shown in Table 1. Perform the same operation as in Example 1 except that
The resolution, sensitivity, profile shape and dimensional change amount of the resist pattern of each resist composition were determined. Table 2 shows the results.

Example 24 The same as Example 1, except that the reduction projection exposure apparatus for i-line used in Example 1 was replaced with HHS-2R manufactured by Hitachi, Ltd. and an electron beam was selectively irradiated with an accelerating voltage of 20 kV. When a resist pattern was obtained by various operations, this resist pattern was a 0.50 μm resist pattern having a good profile shape that was substantially perpendicular to the silicon wafer surface, and the sensitivity at a residual film ratio of 90% was 3.0 μC / cm ² Met. In addition, an appropriate dose of electron beam for obtaining a 0.50 μm resist pattern is set separately, and the set dose is set to ± 15.
When the dimensional change when% changed was determined, it was ± 0.07
μm.

Example 25 2- (p-methoxyphenyl) -4, used in Example 1,
6-bis (trichloromethyl) -1,3,5-triazine and i
And a reduction projection exposure apparatus for lines, respectively, and 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -1,3,5
A resist pattern was obtained by the same operation as in Example 1 except that triazine and a reduction projection exposure apparatus for g-line were replaced, and this resist pattern had a good profile shape that was substantially perpendicular to the silicon wafer surface. It has a resist pattern of 0.55 μm and its sensitivity is
It was 90ms. In addition, an appropriate dose for obtaining a resist pattern of 0.50 μm is set separately, and the set dose is ±
When the amount of dimensional change when changing by 15% was calculated, it was ± 0.
It was 08 μm.

Comparative Example 1 A resist pattern was obtained in the same manner as in Example 1 except that the cresol novolac resin in Example 1 was replaced with a phenol novolac resin, and the obtained resist pattern had a resolution of 0.70 μm, a sensitivity of 200 ms, and a broad spread. And the dimensional change was ± 0.3 μm.

Comparative Example 2 The procedure of Example 1 was repeated except that the weight ratio of m-cresol and p-cresol in Example 1 was changed to 25:75.
Although it was 0.60 μm, the sensitivity was 120 ms, and the amount of dimensional change was ± 0.1 μm, the cross-sectional shape had a soot-like spread.

 ─────────────────────────────────────────────────── ───Continued from the front page (56) References JP-A 2-146044 (JP, A) JP-A 2-217855 (JP, A) JP-A 62-164045 (JP, A) JP-A 53- 133428 (JP, A) JP 4-226454 (JP, A) JP 4-230757 (JP, A) JP 4-358155 (JP, A)

Claims (3)

(57) [Claims] 1. A cresol novolac resin obtained from a phenolic compound containing (A) 30% by weight or more of m-cresol, and (B) a general formula. (Z in the formula is R ¹ and R ² are an alkyl group having 1 to 5 carbon atoms, R ³ and
R ⁴ are each a hydrogen atom, a hydroxyl group or a carboxyl group, and they may be the same or different from each other), and (C) an alkoxymethylated urea resin. A negative-type radiation-sensitive resist composition containing the same. 2. A cresol novolac resin as the component (A) contains 30% by weight or more of m-cresol, and p-cresol, 2,5-xylenol and 3,5 as the remaining components.
A negative-type radiation-sensitive resist composition according to claim 1, which is obtained from a mixed phenolic compound containing at least one selected from xylenol. 3. A mixed phenolic compound is m-cresol.
The negative radiation-sensitive resist composition according to claim 2, which comprises 55 to 75% by weight and 45 to 25% by weight of at least one selected from p-cresol and 3,5-xylenol.