JPH0743903A - Resist material and formation of pattern using the same - Google Patents

Abstract

PURPOSE:To provide the chemical amplification type resist material having excellent exactness of patterns and excellent controllability of pattern sizes. CONSTITUTION:This resist material is composed to include a resin compsn. which is changed in solubility to an aq. alkaline soln. by an acid and an absorbance changeable acid generating agent which generates an acid simultaneously with degradation in absorbance by irradiation with UV rays or far UV rays. The resist material is otherwise composed to include an acid generating agent which generates an acid and a dyestuff compd. which is degraded in absorbance by the irradiation with the UV rays, etc., in addition with the resin compsn. A color fading reaction progresses during exposure by applying the exposure sufficient to generate the acid necessary for the change in the solubility of the resin compsn. to the patterns when this resist material is applied on a substrate 1 and the patterns 2A are formed by subjecting the resist material to a treatment, such as irradiation with the UV rays 4, etc., and therefore, there is no degradation in resolution even if the resist having low initial transmittance is used. The influence of the reflection from the substrate 1, such as standing wave and halation, is suppressed and the exact patterns 2A are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist material used for pattern formation when manufacturing a semiconductor element or an integrated circuit, and a pattern forming method using the resist material.

[0002]

2. Description of the Related Art Conventionally, fine pattern formation in the manufacture of ICs and LSIs is carried out by photolithography using ultraviolet rays. In recent years, with the miniaturization of elements, the wavelength of the exposure light source has been shortened, and further, the development of a resist corresponding to the short wavelength light source has been promoted. As a resist compatible with a short wavelength light source, a resist introduced with a concept called chemical amplification has been developed for the purpose of obtaining high transparency, high resolution and high sensitivity to short wavelength light. This resist is a multi-component substance containing an acid generator that generates an acid when irradiated with ultraviolet rays or deep ultraviolet rays, and a resin composition that changes in solubility in an alkaline aqueous solution which is a developer by reacting with an acid. is there.

An example of a pattern forming method using the above-described conventional chemically amplified resist will be described below with reference to FIG. FIG. 6 shows a cross section of a substrate in a conventional pattern forming process.

First, a chemically amplified resist material having the following composition: poly (p-tert-butoxycarbonyloxystyrene) 10.0 g triphenylsulfonium hexafluorophosphate 0.2 g ethylcellosolve acetate 40.0 g was prepared, and 1 After this resist material is dropped onto and spin-coated, baking is performed for 1 minute on a hot plate at 90 ° C. to form a resist film 2 having a thickness of 1.0 μm. The transmittance of the resist film 2 for far ultraviolet rays having a wavelength of 248 nm is about 55%.

Next, as shown in FIG. 6A, the resist film 2 is irradiated with a KrF excimer laser beam 4 having a wavelength of 248 nm through a mask 3.

At this time, if the irradiation of the KrF excimer laser light is continued, as shown in FIG. 6B, in the semiconductor substrate 1 including the step, reflection occurs in an oblique direction from the step, so that a portion which is not originally exposed is exposed. Exposed by reflected light 4,
The exposure area extends to below the light shielding portion of the mask 3 (see the broken line in the figure).

After that, as shown in FIG.
After baking on a hot plate at ℃ for 1 minute,
The resist pattern 2A is formed by developing for 1 minute with an organic alkaline aqueous solution.

[0008]

At this time, when the above-mentioned conventional resist material is used, as described above, in the semiconductor substrate 1 including the step, since there is oblique reflection from the step, the portion which is not originally exposed is exposed. Is exposed by the reflected light, so that the portion of the resist pattern 2A that should remain is removed as shown in FIG. 6C. That is, a phenomenon called halation occurs in which the reflected light prevents accurate transfer of the mask 3.

On the other hand, FIG. 7 is a graph showing the variation of the pattern dimension depending on the resist film thickness, and shows the effect of so-called standing wave caused by multiple interference of incident light and reflected light inside the resist. When the film thickness of the applied resist material changes by several tens of nm, the energy accumulated in the resist film varies greatly depending on whether there is a node or an antinode of the waveform of the standing wave at the surface position of the resist film. May vary by 0.1 μm or more.

That is, as described above, particularly on a substrate having a high reflectance and a step, when a fine pattern is transferred, the transfer becomes inaccurate and it is difficult to control the pattern size with high accuracy. To be

In this case, looking at the causes of the halation and the standing wave, these phenomena are caused by reflected light on the surface of the substrate or the interface between the resist film and the outside. Becomes higher, or the more light is reflected at the interface between the resist film surface and the outside after being reflected by the substrate surface inside the resist film, the more remarkable. That is, it depends on the reflectance of the substrate and the light transmittance of the resist film.

Therefore, in order to avoid this effect, an antireflection film that absorbs light is formed on the substrate to reduce the reflectance of the substrate surface, or a dye compound is added to the resist material to increase the transmittance. It is possible to reduce the amount.
However, the former method may complicate the process and may cause a dimension shift during etching, and the latter method may deteriorate the resolution of the resist.

As described above, the chemically amplified resist exhibits a high resolution due to its high light transmittance, but on the other hand, it has a high transmittance, and therefore, as described above, particularly on a stepped substrate having a high reflectance, halation may occur. However, the effect of standing waves is also increased, which hinders accurate formation of fine patterns and high-precision dimensional control, and there is a problem that the excellent characteristics are not fully utilized.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a chemically amplified resist material whose solubility in an alkaline aqueous solution is changed by the generation of an acid and a pattern forming method using the same, in which ultraviolet rays or By giving a certain degree of absorbance before the irradiation of far-ultraviolet light, and by having the function of changing the absorbance with the progress of irradiation, while suppressing the deterioration of resolution, mitigating the effects of standing waves and halation, Therefore, it is intended to improve the accuracy of the pattern and the controllability of the pattern dimension.

[0015]

In order to achieve the above object, the means of the invention of claim 1 is applied to a substrate such as a semiconductor substrate to form an acid as a resist material for forming a predetermined pattern. Reacting in the presence of the resin composition, the solubility of which changes in an aqueous alkali solution, and the irradiation of ultraviolet rays or far ultraviolet rays of a predetermined wavelength, the absorbance for the ultraviolet rays or far ultraviolet rays of the predetermined wavelength at the same time the resin composition The composition has an absorbance-changing acid generator that generates an acid capable of inducing a reaction of a substance.

According to a second aspect of the invention, in the invention of the first aspect, the absorbance-changing acid generator is irradiated with ultraviolet rays or far ultraviolet rays having a predetermined wavelength to reduce the absorbance for ultraviolet rays or far ultraviolet rays. It is intended.

According to a third aspect of the present invention, in the invention of the second aspect, the acid generating characteristic and the absorbance changing characteristic of the absorbance changing acid generator are treated with ultraviolet rays or UV rays in a state in which a resist material is applied. When irradiated with far ultraviolet rays, when the amount of acid necessary for changing the solubility of the resin composition in the entire thickness in the aqueous alkaline solution is generated at the latest, the absorbance of the light absorption necessary for improving the light transmittance of the entire resist material The structure is adjusted so that the reduction reaction is completed.

According to a fourth aspect of the present invention, in the above-mentioned first, second or third aspect of the present invention, the absorbance-changing acid generator has a wavelength of ultraviolet rays or deep ultraviolet rays.
It has a maximum absorption.

According to a fifth aspect of the present invention, a resist material coated on a substrate such as a semiconductor substrate and used as a resist material for forming a predetermined pattern reacts in the presence of an acid and has a solubility in an alkaline aqueous solution. A changing resin composition,
Upon irradiation with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength, an acid generator that generates an acid capable of inducing a reaction of the resin composition,
It is configured to have a dye compound whose absorbance changes with respect to the ultraviolet ray or the deep ultraviolet ray having the predetermined wavelength upon receiving the irradiation with the ultraviolet ray or the deep ultraviolet ray having the predetermined wavelength.

According to a sixth aspect of the present invention, in the above-mentioned fifth aspect of the invention, the dye compound has a reduced absorbance for ultraviolet rays or far ultraviolet rays upon irradiation with ultraviolet rays or far ultraviolet rays having the predetermined wavelength. It is a thing.

According to a seventh aspect of the invention, in the above-mentioned sixth aspect of the invention, the acid generating characteristic of the acid generating agent and the absorbance changing characteristic of the dye compound are changed to ultraviolet rays or ultraviolet rays in a state in which a resist material is applied. When irradiated with deep ultraviolet rays, when the amount of acid necessary for changing the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated at the latest, the above dye necessary for improving the light transmittance of the entire resist material. The composition is adjusted so that the reaction of decreasing the absorbance of the compound is completed.

The means taken by the invention of claim 8 is the invention of claim 7, wherein the acid generation rate of the acid generator is reduced by the absorbance of the dye compound upon irradiation with ultraviolet rays or far ultraviolet rays having a predetermined wavelength. It is configured to be adjusted to be lower than the rate.

According to a ninth aspect of the invention, in the invention of the fifth, sixth, seventh or eighth aspect, the dye compound has a maximum absorption for light having a wavelength in the ultraviolet ray or far ultraviolet ray region. It is what

According to a tenth aspect of the invention, means for protecting the resin composition in the invention of the first, second, third, fourth, fifth, sixth, seventh, eighth or ninth aspect is stable against acid. Group-containing phenolic resin, a combination of an alkali-soluble phenolic resin and an acid-labile protective group,
It is configured to have at least one of a combination of an alkali-soluble phenolic resin and a compound having a property of being crosslinked by the action of an acid.

[0025] The means of the invention as set forth in claim 11 is to subject the resin composition, which reacts in the presence of an acid to change its solubility in an aqueous alkali solution, to an ultraviolet ray or a deep ultraviolet ray having a predetermined wavelength to give the above-mentioned predetermined amount. As a pattern forming method using a resist material having an absorbance-changing acid generator that generates an acid capable of inducing a reaction of the resin composition at the same time that the absorbance with respect to ultraviolet rays or far ultraviolet rays having a wavelength changes, a substrate such as a semiconductor substrate On the above, the step of forming the resist film by applying the resist material and heat-treating, and by irradiating the ultraviolet ray or the far ultraviolet ray of the predetermined wavelength through a mask, the absorbance of the absorbance-changing acid generator is changed. However, the reaction of the resin composition with the acid is promoted by performing the step of generating an acid from the absorbance-changing acid generator and the heat treatment. A step of changing the solubility Te and developed in the resist film by an alkaline aqueous solution, a method of providing and forming a resist pattern.

According to a twelfth aspect of the present invention, the resin composition reacts in the presence of an acid to change its solubility in an alkaline aqueous solution, and is irradiated with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength to produce the above resin. An acid generator that generates an acid capable of inducing a reaction of the composition, and a dye compound that changes its absorbance with respect to the ultraviolet ray or the far ultraviolet ray having the predetermined wavelength when irradiated with the ultraviolet ray or the far ultraviolet ray having the predetermined wavelength are provided. As a pattern forming method using a resist material, a step of applying the resist material on a substrate such as a semiconductor substrate and forming a resist film by heat treatment, and irradiating the ultraviolet ray or the far ultraviolet ray having the predetermined wavelength through a mask Thus, a step of generating an acid from the acid generator while changing the absorbance of the dye compound, and a heat treatment are carried out to remove the acid by the acid. A step of changing the solubility to facilitate the reaction of the resin composition, followed by development of the resist film by an alkaline aqueous solution, a method of providing and forming a resist pattern.

According to a thirteenth aspect of the present invention, in the method according to the twelfth aspect, the acid generation characteristic of the acid generator and the absorbance change characteristic of the dye compound are treated with ultraviolet rays or UV rays in a state in which a resist material is applied. When irradiated with far ultraviolet rays,
Before the amount of acid required to change the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated, the reaction of changing the absorbance of the dye compound necessary for improving the light transmittance of the resist film is completed. In addition, the step of irradiating the ultraviolet ray or the far ultraviolet ray having the predetermined wavelength is performed until the amount of acid necessary for changing the solubility of the resin composition in the entire thickness from the acid generator is generated. is there.

[0028]

With the above construction, in the invention of claim 1, when the resist material is applied onto the substrate for pattern formation, when the material is exposed to ultraviolet rays or deep ultraviolet rays, the resist material is changed in absorbance. Since the generator is included, the light transmittance of the resist film varies greatly between the initial stage of ultraviolet irradiation and the end of irradiation, but the light transmittance of the resist film is average over the entire exposure period. It becomes a value. Therefore, the halation caused by the reflection from the step portion is reduced, and the variation in the pattern dimension caused by the standing wave in the resist film is also reduced, while the resolution caused by the existence of the light-absorbing substance called the light-absorbency changing acid generator is reduced. Will be suppressed.

According to the second aspect of the invention, when the resist material is applied and irradiated with ultraviolet rays or the like, the transmittance of the resist film is initially low, so that the unexposed portion in the opening area of the mask is exposed. While absorbing the exposure light sufficiently, the absorbance-changing acid generator decreases the absorbance simultaneously with the generation of acid as the exposure progresses, so that the light transmittance of the resist film is improved. Therefore, the portion of the opening area of the mask which is exposed by the direct incident light is improved in light transmittance at the end of the exposure step and is exposed to the bottom of the resist, so that the resolution is not lowered. On the other hand, since ultraviolet rays are absorbed in the resist film, the reflected wave is sufficiently weak, and the reflected light to the area covered by the mask is easily absorbed, reducing the effects of halation and standing waves. To do.

According to the third aspect of the present invention, by adjusting the acid generation characteristics and the absorbance change characteristics of the absorbance-changeable acid generator, when the resist material is coated with ultraviolet rays or deep ultraviolet rays, at the latest, all the rays are irradiated. When an amount of acid necessary for changing the solubility of the resin composition in the thickness in the alkaline aqueous solution is generated, the reaction of decreasing the absorbance required for improving the light transmittance of the resist material is completed, and therefore, at the end of exposure. The light transmittance of the resist material is surely increased, and the resolution is maintained excellent.

In the invention of claim 4, the absorbance-changing acid generator has a maximum absorption for ultraviolet or far-ultraviolet light, so that the change in absorbance with respect to irradiation with ultraviolet or far-ultraviolet becomes particularly large, The action of the invention of claim 1, 2, or 3 becomes remarkable.

In the inventions of claims 5 to 7, the same effects as those of the inventions of claims 1 to 3 can be obtained due to the acid generating action of the acid generator and the absorbance change characteristic of the dye compound due to the irradiation of ultraviolet rays.

In the invention of claim 8, it is easy to adjust the acid generation rate at the time of irradiation with ultraviolet rays and the like by adjusting the addition amount of the acid generator and the like. Therefore, the solubility of the resin composition in the total thickness in an alkaline aqueous solution is Can be easily adjusted so that the reaction of decreasing the absorbance is completed when the required amount of acid is generated, and the light transmittance of the resist material surely becomes high at the end of the exposure, and the resolution is easily good. Secured in.

In the invention of claim 9, since the dye compound has the maximum absorption for the light of ultraviolet rays or far ultraviolet rays,
The change of the absorbance with respect to the irradiation of ultraviolet rays or far ultraviolet rays becomes particularly large, and the effect of the invention of claim 5, 6, 7 or 8 becomes remarkable.

According to the tenth aspect of the invention, whether the resin composition is a so-called negative type or positive type, the phenol resin, in particular, has a high transmittance for ultraviolet rays or far ultraviolet rays, and therefore maintains a high resolution. However, the action of each invention can be obtained.

In the eleventh aspect of the invention, in the step of irradiating the resist material containing the absorbance changing acid generator with ultraviolet rays or deep ultraviolet rays, the absorbance changes simultaneously with the generation of acid from the absorbance changing acid generator. The light transmittance of the resist film during the entire period of irradiation with ultraviolet rays or the like is an intermediate value. That is, in the region of the resist film adjacent to the opening of the mask, halation due to reflection from the step portion is reduced, and variation in pattern size due to standing waves in the resist film is also reduced. On the other hand, in the opening portion of the mask, the light transmittance of the resist film during irradiation with ultraviolet rays or the like is not so low on average, so that the deterioration of resolution is suppressed.

According to the twelfth aspect of the invention, the above-mentioned first aspect is obtained by the change in the absorbance of the dye compound and the acid generation of the acid generator.
The same effect as that of the first aspect of the invention can be obtained.

According to the thirteenth aspect of the present invention, by adjusting the acid generating characteristics of the acid generator and the absorbance change characteristics of the dye compound,
In the irradiation process of ultraviolet rays or deep ultraviolet rays to the resist,
When the amount of acid necessary for changing the solubility of the resin composition in the total thickness in the aqueous alkali solution is generated at the latest, the reaction of decreasing the absorbance necessary for improving the light transmittance of the resist film is completed, so that the exposure At the end, the light transmittance of the resist material is surely increased, and the resolution is maintained particularly good.

[0039]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) First, Embodiment 1 will be described with reference to FIGS.

Here, FIGS. 1A to 1C are views showing steps for forming a fine pattern, and FIGS. 2A to 2C are views before and during irradiation with the KrF excimer laser beam 4, respectively. It is a figure which expands a part of substrate at the time of completion | finish of irradiation, and shows the changed state in a resist film.

First, a resist material having the following composition: diethylene glycol dimethyl ether 40 g poly (p-tert-butoxycarbonyloxystyrene) 10.0 g (matrix polymer) benzoin tosylate 0.5 g (absorbance changing acid generator) was prepared, and this resist was prepared. The material is dropped on the semiconductor substrate 1, spin-coated at 3000 rpm, baked at 90 ° C. for 1 minute, and 1 μm.
A thick resist film 2 is formed.

Here, benzoin tosylate has the following chemical formula

[Chemical 1] Has a molecular structure represented by the following formula, and has a characteristic that the absorbance is maximum with respect to light having a wavelength of around 248 nm (maximum absorption characteristic), and decomposes by exposure to generate an acid and generate 248
The compound capable of changing to a compound having a low absorbance for light having a wavelength near nm, and is the absorbance-changing acid generator according to claim 1.

Subsequently, as shown in FIG. 1A, a 248 nm KrF excimer laser beam 4 was irradiated through the mask 3. At this time, before the irradiation with the KrF excimer laser light 4, as shown in FIG. 2A, the benzoin tosylate particles 5 are dispersed in the resist film 2 over the entire cross section. In this state, the transmittance of the resist film for far ultraviolet rays of 248 nm is about 40%, which is considerably lower than the light transmittance of the conventional chemically amplified resist film. The light transmittance is
An ultraviolet-transparent substrate such as a quartz substrate is used instead of the semiconductor substrate 1 and a resist film is formed, so that the measurement can be easily performed.

By irradiating the KrF excimer laser beam 4 of 248 nm, a region having a high light transmittance (the unhatched portion in FIG. 1A) is moved downward from the upper side to the lower side of the opening of the mask 3. Expanding. That is, FIG.
As shown in (b), in the upper region of the resist film 2, the benzoin tosylate particles 5 are decomposed by irradiation of the KrF excimer laser light 4 to generate an acid, and
This is due to the change to particles 5a made of a compound having a low absorbance.

At the end of the exposure process, the process shown in FIG.
As shown in (b), the opening portion of the mask 3 is a region having a high light transmittance over the entire cross section (unhatched portion in FIG. 1B).
Has become. That is, as shown in FIG. 2C, the benzointosylate particles 5 are changed to the compound particles 5 a having a low absorbance over the entire cross section of the resist film 2.
At this time, the transmittance of the resist film 2 for the KrF excimer laser light is about 60%.

After that, as shown in FIG.
The resist pattern 2A is obtained by baking at 1 ° C. for 1 minute to decompose the t-butoxycarbonyl group, and then developing with a 2.38% tetramethylammonium hydroxide aqueous solution for 1 minute.

Further, in FIG. 3, the above resist material is applied onto a semiconductor substrate and baked at 90 ° C. for 1 minute,
A resist film having a thickness of 0.9 μm to 1.1 μm is formed, and the obtained resist film is irradiated with a 248 nm KrF excimer laser beam through a mask and baked at 110 ° C. for 1 minute, and then, with an organic alkali aqueous solution. The pattern dimension changes with the resist film thickness obtained by measuring the line and space pattern of 0.3 μm after development for 1 minute. The minimum value is 0.93 μm, and the maximum value is 0.97 μm. , The difference is 0.07 μm. This value is sufficiently smaller than the difference between the maximum value and the minimum value of the conventional chemically amplified resist of 0.15 μm (see FIG. 7).

That is, in this embodiment, the benzoin tosylate particles 5 which are the light-absorbency-changing acid generators before being exposed have a sufficient light-absorbance for exposure light.
Although the resist film 2 before exposure has a low transmittance, when it is decomposed by exposure, it becomes compound particles 5a having low absorption of exposure light, and as a result, the light transmittance of the entire resist film 2 is improved (recovered) at the end of the exposure.

That is, during pattern formation, the main factors that hinder the accuracy of the pattern are halation caused by reflection from the interface between the resist film and the substrate (especially noticeable at the step portion), and inside the resist film surface. There are variations in size due to standing waves generated by multiple interference of reflected light to the light and deterioration in resolution due to low light transmittance of the resist film. Then, if any one of these elements becomes remarkable, the pattern accuracy as a whole deteriorates even if the other elements are excellent. Therefore, as in the conventional case, in the case of a resist material containing no dye compound, since the light transmittance of the resist film is high from the beginning of exposure, halation occurs in the resist pattern due to scattering by the step portion (see FIG. 6).
(See (c)), the high light transmittance causes a large variation in dimensions due to standing waves. On the other hand, as in Example 1 above, the presence of the benzointosylate particles 5 having a high absorbance at the beginning of the exposure causes the light transmittance of the entire resist film 2 for the KrF excimer laser light 4 to be low, so that the reflection from the substrate step Halation caused by light and dimensional variation caused by standing waves are suppressed. However,
As it is, the resolution may be deteriorated due to the low light transmittance, but the light transmittance of the resist film 2 as a whole is also changed by changing the benzointosylate particles 5 to the compound particles 5a having low absorbance as the exposure progresses. The increase in the resolution and the reduction in the resolution are suppressed.

The above relationship is shown in Table 1 below.

[Table 1] (However, in Table 1, ⊚ indicates that the characteristics are particularly improved, ∘ indicates that the characteristics are improved, Δ indicates that the characteristics are not affected, and × indicates that the characteristics are deteriorated.) . That is, the resist material of the present invention contains benzoin tosylate, which is an acid generator having a high absorbance, so that the resolution is lowered to some extent. It is possible to improve the dimensional variation element due to waves,
Therefore, it is possible to maintain the pattern dimension accuracy and improve the dimension controllability at the time of pattern formation.

In the above-mentioned Example 1, the acid generation and the absorbance change of the absorbance-changing acid generator are made to proceed at the same time, but even if there is a difference in the substantial progress of both due to the strength of the acid. Let's be good. However, when ultraviolet rays or deep ultraviolet rays are applied while the resist material is applied,
When at least the amount of acid necessary for changing the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated at the latest, it is necessary to adjust so that the reaction of decreasing the absorbance necessary for improving the light transmittance of the resist film is completed. Therefore, the effect of improving the pattern accuracy and the like is great.

Further, in the above-mentioned Example 1, a two-component type positive resist was used in which the polymer compound in which the hydroxyl group of polyvinylphenol was substituted was used as the resist matrix polymer. However, 3 containing an alkali-soluble polymer and a dissolution inhibitor was used. Similar effects can be obtained with either a component type positive resist or a negative resist containing an alkali-soluble polymer and a crosslinking agent.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS.

FIG. 4 is a diagram showing a changed state in the resist film in the fine pattern forming process of the second embodiment.

First, the following composition poly (p-tert-butoxystyrene) 5 g (matrix polymer) 2,6-dinitrobenzyl tosylate 0.2 g (acid generator) 5-diazo-meldrumic acid 0.8 g (colorant compound) Prepare resist material.

Here, the above-mentioned 5-diazo-meldrum acid is
The following chemical formula

[Chemical 2] It has a molecular structure represented by, and exhibits maximum absorption near the wavelength of 248 nm of KrF excimer laser light before being exposed, and by irradiation with KrF excimer laser light, a diazo group is cleaved to cause a chemical change, The absorption for deep ultraviolet rays of 248 nm, that is, the absorbance is reduced.

Next, a pattern is formed on the semiconductor substrate 1 using this resist material, and the change of the entire substrate at that time is almost the same as the change shown in FIGS. 1A to 1C in the first embodiment. Since it is the same, illustration is omitted. This resist material is dropped on the semiconductor substrate 1, spin-coated, and baked at 100 ° C. for 1 minute to form a resist film 2 having a thickness of 1 μm. In this state,
As shown in (a), 2,6-dinitrobenzyl tosylate particles 6 as an acid generator and 5-diazo-meldrum acid particles 7 as a dye compound are present in the resist film 2. , KrF excimer laser light 4 on resist film 2
The transmittance for (far ultraviolet rays of 248 nm) is about 40%. Then, the resist film 2 has a K of 248 nm.
By irradiating the rF excimer laser beam 4 as shown in FIG.
As shown, in the upper unhatched portion, the 2,6-dinitrobenzyl tosylate particles 6 become acidic compound particles 6a, and the Meldrum's acid particles 7 have a low absorbance.
Changes to. Then, when the exposure step is completed, almost all the 5-diazo-Meldrum's acid 7 which is a dye compound is converted into compound particles 7a having a low absorbance. The transmittance of the resist film 2 in this state is about 55%.

That is, in this embodiment, the substance having a high absorbance in the resist film 2 before being exposed is the dye compound, 5-diazo-meldrum acid 7. This dye compound undergoes a chemical change upon exposure to light, and its absorption of far ultraviolet rays of 248 nm decreases. Since the reaction efficiency of 2,6-dinitrobenzyl tosylate, which is the acid generator used here, with far-ultraviolet rays is low, the reaction of the dye compound takes precedence over the reaction of the acid generator. Therefore, the reaction of the dye compound is completed and the transmittance of the resist film 2 is recovered by the time the amount of acid required for pattern formation is generated.

Therefore, by the same operation as that of the first embodiment, it is possible to form a pattern accurately without being influenced by reflection even on a substrate having a step and a high reflectance.

Further, in FIG. 5, the film thickness is 0.9 μm to 1.1 μm.
The dimensional change of 0.3 μm line-and-space pattern when the thickness is changed in μm is shown. The minimum value is 0.93 μm, the maximum value is 0.97 μm, and the difference is 0.05.
μm. This value is sufficiently smaller than 0.15 μm of the conventional chemically amplified resist.

As described above, according to the second embodiment, the chemically amplified resist contains a compound capable of absorbing exposure light and reacting with the exposure light to reduce its absorbance.
By suppressing the sensitivity to the exposure dose with which this compound reacts, the fading reaction of the resist is promoted during exposure, and accurate pattern formation becomes possible without being affected by the resist film thickness and reflection.

In the second embodiment, as defined in claim 6, the acid generating characteristic of the acid generating agent and the absorbance changing characteristic of the dye compound are irradiated with ultraviolet rays or deep ultraviolet rays in the state in which the resist material is applied. When the amount of acid necessary for the change in the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated at the latest, that is, at the end of the exposure,
Although the adjustment is made so that the reaction of decreasing the absorbance of the dye compound necessary for improving the light transmittance of the resist film 2 is completed, the dye compound necessary for improving the light transmittance of the resist film 2 is not necessarily required at the end of the exposure. It is not necessary that the reaction of decreasing the absorbance is completed, and if the transmittance of the resist film 2 is improved (recovered) to some extent, the effect of improving the pattern accuracy and the like can be obtained. However, by doing so, the effect of suppressing the deterioration of the resolution becomes large, so that the effect of improving the pattern accuracy and the like is also large. Further, in order to give priority to the action of decreasing the absorbance of the dye compound over the action of generating the acid, the acid generation rate of the acid generator is set to be lower than that of the dye compound as in Example 2 above. Alternatively, the generated acid may be a weak acid.

In Example 2 above, 5-diazo-meldrumic acid was used as the dye compound, but other diazo-
The same effect can be obtained by using a dicarbonyl compound.
For example, 1-diazo-2,6-dicarbonylcyclohexane,
3-diazo-2,4-dicarbonylpentane, 1-diazo-2,6-
Dicarbonyl-4,4-dimethylcyclohexane, 1-ethoxy-2-diazo-1,3-dicarbonylbutane, 3,8-diazo-
2,4,7,9- Tetracarbonyldecane, 2-diazo-1,3-dicarbonyl-1- (N, N-dimethylamino) butane, 2-diazo-1,3-dicarbonyl-1- (N , N-Diethylamino) butane, 4-diazo-3,5-dicarbonyl-1,7-diphenylheptane, 4-diazo-3,5-dicarbonyl-1,7-di (p-methylphenyl) heptane, 4 -Diazo-3,5-dicarbonyl-1,7
-Since the absorbance of di (p-chlorophenyl) heptane or the like changes by irradiation with far ultraviolet rays, the same effect can be obtained by using it as a dye compound.

In Example 2, a two-component positive resist was used in which the polymer compound in which the hydroxyl group of polyvinylphenol was substituted was used as the resist matrix polymer. However, 3 containing an alkali-soluble polymer and a dissolution inhibitor was used. Similar effects can be obtained with either a component type positive resist or a negative resist containing an alkali-soluble polymer and a crosslinking agent.

Further, depending on the conditions, whether the absorbance-changing acid generator in Example 1 and the acid-generating agent as in Example 2 are used in combination, or whether the absorbance-changing acid generator and the dye compound are used in combination. Alternatively, the absorbance-changing acid generator, the acid generator and the dye compound may be used in combination.

Furthermore, the absorbance-changing acid generator in Example 1 or the dye compound in Example 2 is
In both cases, the one with high absorbance was used before UV irradiation, and the absorbance was decreased by UV irradiation.On the contrary, the one with low absorbance was used before UV irradiation and the absorbance was increased with UV irradiation. Even in this case, since the light transmittance during the exposure process is averaged, the same effect as that of each of the above embodiments can be obtained.

[0068]

As described above, according to the invention of claim 1, as a resist material for forming a predetermined pattern on a substrate such as a semiconductor substrate, it reacts in the presence of an acid to dissolve in an alkaline aqueous solution. Since the resin composition having a changeable property and a composition having an absorbance-changing acid generator that generates an acid at the same time that the absorbance changes when it is irradiated with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength, the resist material is on the substrate. In the coated state, by setting the light transmittance of the resist film to an average value during the period in which ultraviolet rays or deep ultraviolet rays are irradiated, halation caused by reflection from the step portion is suppressed while suppressing deterioration of resolution. It is possible to reduce the variation in the pattern dimension due to the standing wave, and thus to improve the accuracy of the resist pattern and the controllability of the pattern dimension. Kill.

According to the invention of claim 2, in the invention of claim 1, the absorbance-changing acid generator is such that the absorbance for ultraviolet rays or the like is lowered by irradiation with ultraviolet rays or far ultraviolet rays having a predetermined wavelength. When the resist material is applied and irradiated with ultraviolet rays or the like, the resolution is improved by maintaining the light transmittance of the resist film low initially and increasing the light transmittance of the resist film at the end of the irradiation step. While maintaining the decrease, it is possible to reduce the effects of halation and standing waves, so that the accuracy of the resist pattern and the controllability of the pattern size can be improved.

According to the invention of claim 3, in the invention of claim 2, the acid generating characteristic and the absorbance changing characteristic of the absorbance-changing acid generator are determined when the resist material is irradiated with ultraviolet rays or deep ultraviolet rays. Since the composition is adjusted so that the reaction of decreasing the absorbance is completed when the generation of the required acid is completed, it is possible to reliably ensure a high light transmittance of the resist film at the end of the exposure. The resolution can be kept good.

According to the invention of claim 4, the above-mentioned claim 1
In the invention of 2 or 3, since the absorbance-changing acid generator has a maximum absorption with respect to light of ultraviolet rays or far ultraviolet rays, it is possible to particularly increase the change of absorbance with respect to irradiation of ultraviolet rays or far ultraviolet rays. Therefore, the effects of the invention of claim 1, claim 2 or claim 3 can be remarkably exhibited.

According to the invention of claim 5, as a resist material for forming a predetermined pattern on a substrate such as a semiconductor substrate, a resin composition which reacts in the presence of an acid to change its solubility in an alkaline aqueous solution. Since the resist composition is coated on the substrate, the composition has an acid generator that generates an acid upon irradiation with ultraviolet rays or far ultraviolet rays, and a dye compound whose absorbance changes upon irradiation with ultraviolet rays. Therefore, by setting the light transmittance of the resist film to an average value during the period of being irradiated with ultraviolet rays or deep ultraviolet rays, while suppressing deterioration of resolution, halation and standing waves caused by reflection from the stepped portion are suppressed. It is possible to reduce the variation in the pattern dimension due to it, and thus it is possible to improve the accuracy of the resist pattern and the controllability of the pattern dimension.

According to the invention of claim 6, in the invention of claim 5, since the absorbance of the dye compound is reduced by irradiation with ultraviolet rays or the like, the absorption of ultraviolet rays or the like is reduced. As a result, the influence of standing waves can be reduced, so that the accuracy of the resist pattern and the controllability of the pattern size can be improved.

According to the invention of claim 7, in the invention of claim 6, the acid generating characteristics of the acid generator and the absorbance change characteristics of the dye compound are determined when the resist material is irradiated with ultraviolet rays or deep ultraviolet rays. Since the adjustment is made so that the reaction of decreasing the absorbance is completed when the generation of acid is completed, the light transmittance of the resist film can be surely ensured to be high at the end of the exposure, and the resolution is particularly high. Can be maintained well.

According to the invention of claim 8, in the invention of claim 7, the acid generation rate of the acid generator is adjusted to be lower than the absorbance decrease rate of the dye compound with respect to irradiation of ultraviolet rays or deep ultraviolet rays. Since it is configured to be kept, it becomes possible to easily adjust so that the reaction of decreasing the absorbance is completed when the amount of acid necessary for the change in the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated. The effect of the invention of Item 7 can be easily obtained.

According to the invention of claim 9, the above-mentioned claim 5,
In the invention of 6, 7 or 8, since the dye compound has the maximum absorption for the light of the ultraviolet ray or the far ultraviolet ray, the change of the absorbance with respect to the irradiation of the ultraviolet ray or the like can be made particularly large. Item 5, 6, 7 or 8
The effect of the invention can be remarkably exhibited.

According to the invention of claim 10, in the invention of claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, the resin composition has an acid-labile protecting group. At least one of a phenolic resin, a combination of an alkali-soluble phenolic resin and a compound having an acid-labile protective group, and a combination of an alkali-soluble phenolic resin and a compound having a property of crosslinking by the action of an acid. Since we have one, so-called negative type,
The effect of each invention can be exhibited while maintaining a high resolution by utilizing the characteristics of the phenol resin having a high transmittance to ultraviolet rays or far ultraviolet rays for any of the positive type.

According to the invention of claim 11, as a pattern forming method using the resist material having the constitution of the invention of claim 1, the resist material is applied on a substrate such as a semiconductor substrate and heat-treated to form a resist film. And a step of irradiating ultraviolet rays or far ultraviolet rays through a mask to generate an acid while changing the absorbance of the absorbance-changing acid generator, and heat treatment to accelerate the reaction of the resin composition to dissolve the resin composition. Since the step of changing the property and the step of developing the resist film with an alkaline aqueous solution to form a resist pattern are provided, while suppressing deterioration of the resolution, halation and standing of the resist caused by reflection from the stepped portion are suppressed. It is possible to reduce variations in pattern dimensions due to waves, and thus improve accuracy of resist patterns and controllability of pattern dimensions. It is possible to achieve the above.

According to the twelfth aspect of the invention, a resin composition which reacts in the presence of an acid to change its solubility in an aqueous alkali solution and an acid generating acid which is irradiated with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength As a pattern forming method using a resist material comprising an agent and a dye compound whose absorbance changes upon irradiation with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength,
A step of applying a resist material on a substrate such as a semiconductor substrate and heat-treating it to form a resist film, and irradiating ultraviolet rays or deep ultraviolet rays of a predetermined wavelength through a mask to change the absorbance of a dye compound and generate an acid. The step of generating an acid from the agent, the step of promoting the reaction of the resin composition by the acid by heat treatment to change the solubility, and the step of developing the resist film with an alkaline aqueous solution to form a resist pattern are provided. Therefore, the same effect as the invention of claim 11 can be exhibited by the change in the absorbance of the dye compound and the acid generation of the acid generator.

According to the invention of claim 13, said claim 1
In the method of 2, the dissolution of the resin composition in the alkali aqueous solution in the entire thickness at the latest in the step of irradiating the resist with ultraviolet rays or deep ultraviolet rays by adjusting the acid generation characteristics of the acid generator and the absorbance change characteristics of the dye compound. When the amount of acid required for the change in the acidity is generated, adjustment is performed so that the reaction of decreasing the absorbance necessary for improving the light transmittance of the resist film is completed, and the irradiation process of ultraviolet rays or the like is completely performed from the acid generator. Since the amount of acid required to change the solubility of the resin composition in the thickness is generated until the amount of acid is generated, the light transmittance of the resist film can be reliably increased at the end of exposure, and therefore, the resolution is particularly good. Can be maintained at.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the procedure of a fine pattern forming method in Example 1.

FIG. 2 is a partial cross-sectional view illustrating a changed state in the resist film during a fine pattern forming process in Example 1.

FIG. 3 is a diagram showing a change in pattern dimension with respect to a change in resist film thickness in Example 1.

FIG. 4 is a partial cross-sectional view illustrating a changed state in the resist film during a fine pattern forming process in Example 2.

FIG. 5 is a diagram showing a change in pattern dimension with respect to a change in resist film thickness in Example 2.

FIG. 6 is a cross-sectional view showing steps of a conventional fine pattern forming method.

FIG. 7 is a diagram showing a change in pattern dimension with respect to a change in resist film thickness in a conventional fine pattern forming method.

[Explanation of symbols]

 1 Semiconductor Substrate 2 Resist Film 2A Resist Pattern 3 Mask 4 KrF Excimer Laser Light 5 Benzoin Tosylate Particles (Absorbance Changeable Acid Generator) 5a Low Absorbance Compound Particles 6,2,6-Dinitrobenzyl Tosylate Particles (Acid Generator) 6a Acid Compound particles 7 5-diazo-meldrum acid particles (dye compound) 7a Low absorbance compound particles

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masako Sasako 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Inside the research institute (72) Inventor Toru Soki Kimura, Kawagoe City, Saitama 1633 Matoba, Wako Pure Chemical Industries, Ltd. Tokyo Research Center

Claims (13)

[Claims] 1. A resin composition which is applied on a substrate such as a semiconductor substrate to form a predetermined pattern, the resin composition reacting in the presence of an acid to change its solubility in an alkaline aqueous solution, It is provided with an absorbance-changing acid generator that generates an acid capable of inducing a reaction of the resin composition at the same time that the absorbance with respect to the ultraviolet ray or the deep ultraviolet ray having the predetermined wavelength changes upon irradiation with the ultraviolet ray or the deep ultraviolet ray having the predetermined wavelength. A resist material characterized in that 2. The resist material according to claim 1, wherein the absorbance-changing acid generator has a reduced absorbance for ultraviolet rays or far ultraviolet rays upon irradiation with ultraviolet rays or far ultraviolet rays having a predetermined wavelength. Resist material. 3. The resist material according to claim 2, wherein the acid-generating property and the light-absorbing property of the light-absorbency-changing acid generator are obtained when ultraviolet rays or deep-ultraviolet rays are applied while the resist material is applied. , When the amount of acid required to change the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated at the latest, adjustment is made so that the reaction of decreasing the absorbance necessary for improving the light transmittance of the entire resist material is completed. A resist material characterized in that 4. The resist material according to claim 1, 2 or 3, wherein the absorbance-changing acid generator has a maximum absorption for light having a wavelength in the ultraviolet ray or far ultraviolet ray region. Resist material. 5. A resin composition, which is applied on a substrate such as a semiconductor substrate to form a predetermined pattern, and which reacts in the presence of an acid to change its solubility in an alkaline aqueous solution, An acid generator that generates an acid capable of inducing a reaction of the resin composition by receiving irradiation with ultraviolet rays or far ultraviolet rays having a predetermined wavelength, and irradiation with ultraviolet rays or far ultraviolet rays having the predetermined wavelength is used. A resist material comprising: a dye compound whose absorbance with respect to ultraviolet rays or deep ultraviolet rays changes. 6. The resist material according to claim 5, wherein the dye compound has a reduced absorbance for ultraviolet rays or far ultraviolet rays upon irradiation with ultraviolet rays or far ultraviolet rays having the predetermined wavelength. 7. The resist material according to claim 6, wherein the acid generating characteristic of the acid generating agent and the absorbance change characteristic of the dye compound are obtained when ultraviolet rays or deep ultraviolet rays are applied while the resist material is applied. When the amount of acid necessary for changing the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated at the latest, the reaction of decreasing the absorbance of the dye compound necessary for improving the light transmittance of the entire resist material is completed. A resist material characterized by being adjusted to 8. The resist material according to claim 7, wherein the acid generation rate of the acid generator is adjusted to be lower than the absorbance reduction rate of the dye compound upon irradiation with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength. A resist material characterized in that 9. The resist material according to claim 5, 6, 7 or 8, wherein the dye compound has a maximum absorption for light having a wavelength in the ultraviolet ray or far ultraviolet ray region. material. 10. Claims 1, 2, 3, 4, 5, 6, 7,
8. The resist material according to 8 or 9, wherein the resin composition comprises: a phenolic resin having an acid-labile protective group; a combination of an alkali-soluble phenolic resin and a compound having an acid-labile protective group; A resist material comprising at least one of a combination of a soluble phenolic resin and a compound having a property of being crosslinked by the action of an acid. 11. A resin composition which reacts in the presence of an acid to change its solubility in an aqueous alkaline solution and is irradiated with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength, and has an absorbance for ultraviolet rays or deep ultraviolet rays having the predetermined wavelength. A pattern forming method using a resist material having an absorbance changing acid generator that generates an acid capable of inducing a reaction of the resin composition at the same time, wherein the resist material is formed on a substrate such as a semiconductor substrate. Apply
A step of forming a resist film by heat treatment, by irradiating the ultraviolet ray or deep ultraviolet ray of the predetermined wavelength through a mask, while changing the absorbance of the absorbance-changing acid generator, the acid from the absorbance-changing acid generator is changed. And a step of promoting the reaction of the resin composition with an acid to change the solubility by heat treatment, and a step of developing the resist film with an aqueous alkaline solution to form a resist pattern. A pattern forming method comprising: 12. A resin composition which reacts in the presence of an acid to change its solubility in an alkaline aqueous solution, and an acid capable of inducing a reaction of the resin composition upon irradiation with ultraviolet rays or deep ultraviolet rays having a predetermined wavelength. In the pattern forming method using a resist material comprising an acid generator that generates an ultraviolet ray or a deep ultraviolet ray having a predetermined wavelength, and a dye compound having a change in absorbance for the predetermined wavelength ultraviolet ray or deep ultraviolet ray. So, apply the above resist material on a substrate such as a semiconductor substrate,
A step of forming a resist film by heat treatment, by irradiating the ultraviolet ray or deep ultraviolet ray of the predetermined wavelength through a mask, while changing the absorbance of the dye compound, a step of generating an acid from the acid generator, It is characterized by comprising a step of accelerating the reaction of the resin composition with an acid to change the solubility by heat treatment, and a step of developing the resist film with an alkaline aqueous solution to form a resist pattern. And a pattern forming method. 13. The pattern forming method according to claim 12, wherein the acid generating characteristic of the acid generating agent and the absorbance changing characteristic of the dye compound are obtained when ultraviolet rays or deep ultraviolet rays are applied while the resist material is applied. In addition, before the amount of acid required to change the solubility of the resin composition in the total thickness in the alkaline aqueous solution is generated, the change reaction of the absorbance of the dye compound necessary for improving the light transmittance of the resist film is completed. Is adjusted so that the irradiation step of ultraviolet rays or far ultraviolet rays of the predetermined wavelength is performed until the amount of acid necessary for changing the solubility of the resin composition in the entire thickness is generated from the acid generator. And a pattern forming method.