JP3307709B2 - Method of forming resist pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a resist pattern, and more particularly, to a method of forming a resist pattern capable of improving a pattern shape, increasing resolution, and forming a stable resist pattern. It relates to a forming method.

[0002]

2. Description of the Related Art Semiconductor integrated circuits have been increasingly integrated and VLSIs have been put into practical use rather than LSIs. The VLSI is realized by miniaturization of a conductor wiring, an electrode, and the like. At present, a VLSI having a minimum pattern of less than 1 μm (submicron) is in practical use. With miniaturization, the light beam used for exposure when forming a resist pattern shifts from a conventionally used ultraviolet ray to a short wavelength, and radiation such as far ultraviolet rays, an electron beam, and X-rays is used. Was.

However, there is a problem that the output of a high-pressure mercury lamp used for exposure is considerably reduced when the output is shifted to far ultraviolet light. Therefore, in order to cope with this problem, studies have been made to use excimer laser light, which is the most powerful coherent light source in the ultraviolet region. On the other hand, in terms of material, high sensitivity can be achieved by using a chemically sensitized resist.

A chemically sensitized resist increases the sensitivity by adding a photoacid generator that generates an acid upon exposure to the resist, and can be applied to both a positive type and a negative type like conventional resists. It is. As the photoacid generator, diaryliodonium salts, triarylsulfonium salts, derivatives thereof, and the like are known.

As a positive type chemically sensitized resist, a resist obtained by mixing a polymer with a photoacid generator is used. When the resist is exposed to light (irradiation with light), Bronsted acid generated from the photoacid generator upon exposure is exposed. By acting as a catalyst, a elimination reaction or a hydrolysis reaction is caused in the polymer in a chain, and a hydrophilic group is formed in the polymer, so that the exposed portion becomes soluble in an alkali developing solution, and a positive resist is formed.

As the negative type chemically sensitized resist, a resist obtained by mixing a photoacid generator and a crosslinking agent with a polymer is used. When the resist is exposed (irradiated with light),
The Brønsted acid generated from the photoacid generator upon exposure acts as a catalyst to decompose the cross-linking agent, and the cross-linking agent cross-links the polymers to form a polymer, making the exposed part insoluble in the alkaline developer. , A negative resist is formed.

However, in a positive type chemically sensitized resist, the photoacid generator is decomposed by exposure,
As shown in FIGS. 4 and I, the acid concentration near the resist surface increases, and the internal bleaching effect for improving the transparency of the resist cannot be expected. For this reason, when this is developed, FIG. 4, J
As a result, the pattern shape becomes a forward taper type as shown in FIG. In addition, since the acid generated by exposure is unstable, after exposure, the sensitivity changes during the exposure time by leaving it to bake after exposure. There is a problem that a hardly soluble layer is formed.

On the other hand, in the case of a negative type chemically sensitized resist, the photoacid generator is decomposed by exposure to light, and FIG.
As shown in the figure, the acid concentration near the resist surface increases,
No internal bleaching effect to improve the transparency of the resist can be expected. Therefore, when this is developed, it becomes an inverted tapered pattern shape as shown in FIG. 4 and L, and it is not possible to increase the resolution. Further, since the acid generated by the exposure is unstable, the acid diffuses into the unexposed area, and FIG.
There is a problem that bridging as shown in (1) is formed.

As described above, the resolution of the chemically sensitized resist cannot be increased, and there is an unstable factor in the pattern forming process, which hinders practical use. Therefore, it is desired to increase the resolution and stabilize the pattern forming process.
The present invention has been made in view of the above-described problems, and provides a method of forming a resist pattern in which a pattern shape is improved, resolution can be increased, and a stable resist pattern can be formed. It is intended to be.

According to the present invention, a positive or negative type chemically sensitized resist containing a photoacid generator and optionally a crosslinking agent is applied to a substrate, the resist is prebaked, and the substrate is exposed before exposure. Is treated in a gas atmosphere of an acid quenching compound to expose the resist, the exposed resist in the case of a positive resist, the unexposed portion of the resist in the case of a negative resist, a resist developed with a developing solution A method for forming a pattern is provided.

The substrate used in the present invention is not particularly limited as long as it is a substrate generally used in manufacturing a semiconductor device, and a silicon substrate or a compound semiconductor can be used. As the compound semiconductor substrate, for example, GaAs, AlGaAs, InAlA
A substrate such as s, InGaAs, InGaAsP, or InP can be used.

The positive type chemically sensitized resist of the present invention comprises a base polymer, a photoacid generator, a dissolution inhibitor and a solvent. However, even if a dissolution inhibitor is not used, it can function as a resist, and the positive type chemically sensitized resist of the present invention can be constituted by a base polymer, a photoacid generator and a solvent.

The base polymer, photoacid generator, dissolution inhibitor and solvent used in the present invention include polymers, photoacid generators, dissolution inhibitors and solvents which are generally used for forming chemically sensitized resists. Can be applied.
Examples of the base polymer include a novolak polymer in which the hydroxyl group is blocked with a substituent in order to reduce the dissolution rate in an alkali developer.
Examples of the substituent introduced to block the hydroxyl group of the novolak polymer include a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, a trimethylsilyl group and the like. ~ 15% is appropriate and 11-14
% Is preferred.

The molecular weight of the base polymer is appropriately selected depending on the developer used and the concentration of the developer.
For example, when a 2.38 wt% tetramethylammonium hydroxide (TMAH) developer is used, when a base polymer having an average molecular weight of about 10,000 or less is used,
The dissolution rate in the developer becomes 100 nm / sec or more, which is not appropriate because the developing process is not stable. When a 2.38% by weight tetramethylammonium hydroxide developer is used, the average molecular weight of the base polymer is suitably about 10,000 to 20,000. However, when a 1.90% by weight tetramethylammonium hydroxide developer is used, a base polymer having an average molecular weight of about 10,000 or less can be used. In this case, about 6
A pattern can be formed in a development time of 0 second, and the development process is stabilized.

As the photoacid generator, for example, triphenyl
Sulfonium or diphenyliodonium compounds
And the like. Triphenylsulfonium compounds
Is, for example, triphenylsulfonium trifluoro
Methanesulfonate (Ph _Three-SCF_ThreeSO_Three) And its
Phenyl, methyl, methoxy, thiophenyl, t
-A compound into which a substituent such as a butyl group is introduced, Ph_Three−SP
F_Five, Ph_Three-SSbF_Five, Ph_Three-SAsF_Five, Ph_Three-S
BF_FourDiphenyliodonium compounds
The thing is Ph_Two-IPF_Five, Ph_Two-ISbF_Five, Ph
_Two-IAsF_FiveAnd the like.

Examples of the dissolution inhibitor include aromatic carboxylic esters such as t-butoxycarbonylated bisphenol A manufactured by Sharp Corporation. In addition, even if the resist does not contain a dissolution inhibitor as a component of the resist, it can function as a resist,
In that case, the resolution limit without film loss is 0.32 μm
l: 1 line / space, slightly lower resolution.

Examples of the solvent include methoxyisopropanol, ethoxyisopropanol, diglyme, ethyl lactate and the like. The composition ratio (weight percentage) of the base polymer, photoacid generator and dissolution inhibitor constituting the positive type chemically sensitized resist is 10 to 20:
0.2 to 1.2: 0 to 4 are suitable, and 14 to 17:
0.4-0.8: 3.0-3.2 is preferable, and the total weight percentage is adjusted to 100 with a solvent.

Next, the negative type chemically sensitized resist of the present invention comprises a base polymer, a photoacid generator, a crosslinking agent and a solvent. Examples of the base polymer and the photoacid generator are the same as those for forming a positive type chemically sensitized resist. As the cross-linking agent used in the present invention, a cross-linking agent generally used for a negative type chemically sensitized resist can be used. For example, triazine, ammonium bichromate, a polyfunctional diazonium salt,
And water-soluble bis azide compounds.

The composition ratio (weight percentage) of the base polymer, the photoacid generator and the crosslinking agent constituting the negative type chemically sensitized resist is 10 to 20: 0.2 to 1.
2: 1-5 are suitable, 14-17: 0.4-1.
0: 1 to 3 is preferable, and the total weight percentage is adjusted to 100 with a solvent. As a method of applying a positive or negative type chemically sensitized resist in the present invention, a commonly used application method can be applied, and examples thereof include a spin coating method, a spray method, and a gas phase application method. The thickness of the chemically sensitized resist is 0.5 μm to 2.0 μm.
μm is appropriate.

In the present invention, the conditions such as temperature and time for pre-baking and post-exposure baking in pre-baking and post-exposure baking are appropriately selected according to the composition of the positive or negative type chemically sensitized resist to be used. Is done. The light beam used for exposure in the present invention is not particularly limited, but a light beam used for forming a fine resist pattern is particularly effective.
That is, far ultraviolet rays are preferably used as the light beam, and in this case, it is preferable to use excimer laser light. The exposure amount is appropriately selected according to the composition of the positive or negative type chemically sensitized resist to be used.

As the developing solution used in the present invention, a developing solution generally used for forming a resist pattern can be used, for example, tetramethylammonium hydroxide (TMAH). The concentration of the developer is appropriately selected according to the molecular weight of the base polymer used. In the present invention, the above-mentioned positive or negative type chemically sensitized resist is applied to a substrate, and the resist applied to the substrate is prebaked and then processed in a gas atmosphere of an acid quenching compound.

The acid quenching compound used in the present invention is a compound capable of decomposing a photoacid generator and / or a compound capable of quenching a Bronsted acid generated from a photoacid generator by exposure to light. Any one may be used as long as it is a silyl compound such as hexamethyldisilazane, heptamethyldisilazane, diethylaminotrimethylsilane, trimethylsilyl chloride or trimethylsilyldiethylamine, or an amine compound such as ethylenediamine or methylamine.

The apparatus used in the present invention for treating a substrate coated with a positive or negative type chemically sensitized resist under a gas atmosphere of an acid quenching compound may be obtained by vaporizing an acid quenching compound. Any device capable of forming the saturated atmosphere and placing the substrate under the saturated atmosphere may be used.
Such a device is mentioned.

The process of treating a substrate coated with a positive or negative type chemically sensitized resist in a gas atmosphere of an acid quenching compound will be described with reference to FIG. In FIG. 1, 1 is a substrate, 2 is a closed container, 3 is an exhaust port, 4 is an acid quenching compound, 5 is a tank containing an acid quenching compound, and 6 is dry nitrogen. First, the acid quenching compound 4 is vaporized by introducing dry nitrogen 6 into the acid quenching compound 4 while bubbling, and the vapor of the acid quenching compound 4 is introduced into the closed container 2 at room temperature to form the acid quenching compound. 4 to form a saturated atmosphere.

Next, the substrate 1 coated with the positive or negative type chemically sensitized resist is allowed to stand in a closed container 2 at room temperature in which a saturated atmosphere of the acid quenching compound 4 is formed. Compound 4 is treated in a gas atmosphere. The standing time (time during which the treatment of the acid quenching compound 4 is performed in a gas atmosphere) and the temperature (treatment temperature) at that time are in the order in which the treatment steps are performed under the gas atmosphere of the acid quenching compound 4, and It is appropriately selected according to the combination of the composition of the chemically sensitized resist used and the acid quenching compound used.

For example, pt-butoxycarbonylhydroxystyrene (t-butoxycarbonylation ratio: 13%, average molecular weight: about 13,000) is used as a base polymer.
A positive type containing 6% by weight, 0.8% by weight of triphenylsulfonium trifluoromethanesulfonate as a photoacid generator, and 3.2% by weight of t-butoxycarbonylated bisphenol A manufactured by Sharp Corporation as a dissolution inhibitor. A chemically sensitized resist can be used. The treatment temperature is suitably room temperature, preferably 23 to 30 ° C.

Thereafter, the substrate 1 is taken out of the sealed container 2 and exposed.

[0028]

According to the present invention, after prebaking, the substrate coated with the positive or negative type chemically sensitized resist is treated in a gas atmosphere of an acid quenching compound so that the light contained in the resist is reduced. The acid generator reacts with the acid quenching compound to decompose and deactivate. The photoacid generator on the surface of the positive or negative type chemically sensitized resist treated under the gas atmosphere of the acid quenching compound is decomposed, so that the concentration of the photoacid generator on the resist surface decreases, and the resist surface has The generation of Bronsted acid is suppressed to a low level.

[0029]

Therefore, by treating the positive or negative type chemically sensitized resist in a gas atmosphere of an acid quenching compound after prebaking, the concentration gradient of Bronsted acid near the surface of the resist and near the substrate is eliminated. In the case of a positive resist, the shape of a portion which dissolves in an alkali developing solution is improved, and in the case of a negative resist, the shape of a portion which does not dissolve in an alkali developing solution is improved.

[0031]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples. Also, percentages (%) used in the following examples mean percentages by weight (% by weight) unless otherwise defined.

Example 1 As a base polymer, pt-butoxycarbonylhydroxystyrene (t-butoxycarbonylation ratio: 13)
%, Average molecular weight: about 13,000), 16% as a photoacid generator, 0.8% as triphenylsulfonium trifluoromethanesulfonate, and Sharp Corporation as a dissolution inhibitor.
A methoxyisopropanol solution containing 3.2% of t-butoxycarbonylated bisphenol A manufactured by Co., Ltd. was prepared to obtain a positive type chemically sensitized resist.

This solution was placed on a 6-inch silicon substrate which had been previously subjected to dehydration baking and hydrophobic treatment with hexamethyldisilazane vapor at 120 ° C. for 40 seconds at 3000 rpm.
Spin coating method at a rotation speed of, and prebaked on a hot plate at 100 ° C for 120 seconds to obtain 1 μm
Then, a resist film having a thickness of 5 mm was formed. Next, using hexamethyldisilazane as an acid quenching compound, the silicon substrate coated with the resist was treated in a gas atmosphere of hexamethyldisilazane using the apparatus shown in FIG.

First, hexamethyldisilazane 4 is vaporized by bubbling dry nitrogen 6 into hexamethyldisilazane 4, and the vapor of hexamethyldisilazane 4 is introduced into closed vessel 2 at room temperature. A saturated atmosphere of hexamethyldisilazane 4 was formed. Thereafter, the sealed container 2 in which the saturated atmosphere of hexamethyldisilazane 4 is formed is kept at 24 ° C., and the silicon substrate 1 coated with the resist is left in the sealed container 2 kept at 24 ° C. for 5 seconds. Thus, the treatment was performed in a gas atmosphere of hexamethyldisilazane 4.

After treatment in a gas atmosphere of hexamethyldisilazane, irradiation with far ultraviolet rays (KrF excimer laser light of 248 nm) in combination with a stepper having a numerical aperture NA = 0.45 was performed at an exposure amount of 60 mJ / cm ^2. , 80 ° C
Baking was performed after exposure for 60 seconds. After baking after exposure, development was performed using an NMD-W developer [2.38% tetramethylammonium hydroxide (TMAH) developer] manufactured by Tokyo Ohka Kogyo Co., Ltd. to obtain a positive resist pattern. Was formed.

The results are shown in FIG. 2 and FIG. FIG.
6 is a graph showing a relationship between a remaining film ratio and an exposure amount, and from this graph, a γ value indicating a contrast of a resist can be obtained. FIG. 3 is a diagram showing a pattern shape of 0.35 μml: 1 line / space.

In this embodiment, the contrast γ value of the resist shown in FIG. 2A was 5.0. The limit that can be resolved without reducing the film thickness is 0.30 μml:
1 line / space, and the pattern shape of 0.35 μm: 1 line / space had an inclination of 85 degrees as shown in FIG. 3C. This allows a 2mm long line / space pattern to be formed on the substrate,
The substrate and the pattern were divided in the line / space direction, gold was deposited on the cut surface, an electron micrograph was taken, and the photograph was observed and observed. 0.35 μm
l: Focus margin of 1 line / space is 1.0
μm. This is the focus width at which the line dimension measured by observing the line / space pattern formed on the substrate with an electron microscope is 0.35 +/− 0.035 μm. The contact hole could be resolved to 0.32 μm. this is,
A contact hole was formed on the substrate, and the pattern was confirmed by observing the pattern with an electron microscope.

Further, a resist film was formed in the same manner as described above, exposed to light by performing a treatment in a gas atmosphere of hexamethyldisilazane, and then left for 1 hour before baking after exposure. However, the pattern size did not increase due to the change in sensitivity due to the standing.

REFERENCE EXAMPLE 2 A resist having the same composition as the resist used in Example 1 was subjected to a treatment in a gas atmosphere of hexamethyldisilazane before baking after exposure, and a gas atmosphere of hexamethyldisilazane was used. A positive resist pattern was formed by repeating the same steps as in Example 1 except that the lower processing time was set to 2.5 seconds and the irradiation was performed with an exposure amount of 70 mJ / cm ² during exposure.

FIG. 3 shows the results. In this example, the contrast γ value of the resist was 6.5.
The limit that can be resolved without film loss is 0.25 μm
1: 1 line / space, and the pattern shape of 0.35 μml: 1 line / space had an inclination of 85 degrees as shown in FIG. 3C. Also, 0.
30 μml: the focus margin of one line / space was 1.0 μm. For contact holes,
Resolution was possible down to 0.30 μm. These were confirmed by the same method as in Example 1.

Further, a resist film was formed in the same manner as above, exposed to light by performing a treatment in a gas atmosphere of hexamethyldisilazane, and allowed to stand for 2 hours before baking after exposure. However, the pattern size did not increase due to the change in sensitivity due to the standing.

Example 3 16% of p-hydroxystyrene (average molecular weight: about 13,000) as a base polymer, 0.8% of triphenylsulfonium trifluoromethanesulfonate as a photoacid generator, and 2 parts of triazine as a crosslinking agent A methoxyisopropanol solution containing 0.0% was prepared to obtain a negative type chemically sensitized resist.

This solution was placed on a 6-inch silicon substrate which had been previously subjected to dehydration baking and hydrophobic treatment with hexamethyldisilazane vapor at 120 ° C. for 40 seconds at 3000 rpm.
Spin coating method at a rotation speed of, and prebaked on a hot plate at 100 ° C for 120 seconds to obtain 1 μm
Then, a resist film having a thickness of 5 mm was formed. Next, using hexamethyldisilazane as an acid quenching compound, the silicon substrate coated with the resist was treated in a gas atmosphere of hexamethyldisilazane using the apparatus shown in FIG. did.

First, dry nitrogen 6 is introduced into hexamethyldisilazane 4 while bubbling, so that hexamethyldisilazane 4 is vaporized. The vapor of hexamethyldisilazane 4 is introduced into closed vessel 2 at room temperature. A saturated atmosphere of hexamethyldisilazane 4 was formed. Thereafter, the sealed container 2 in which the saturated atmosphere of hexamethyldisilazane 4 is formed is kept at 24 ° C., and the silicon substrate 1 coated with the resist is left in the sealed container 2 kept at 24 ° C. for 5 seconds. Thus, the treatment was performed in a gas atmosphere of hexamethyldisilazane 4.

After treating in a gas atmosphere of hexamethyldisilazane, irradiation with far ultraviolet rays (KrF excimer laser light of 248 nm) is performed in combination with a stepper having a numerical aperture NA = 0.45 at an exposure amount of 30 mJ / cm ^2. , 110
A post-exposure bake was performed at 60 ° C. for 60 seconds. After the post-exposure bake, development was performed using an NMD-W developer [2.38% tetramethylammonium hydroxide (TMAH) developer] manufactured by Tokyo Ohka Kogyo Co., Ltd. to obtain a negative resist pattern. Was formed.

The results are shown in FIGS. 2 and 3. In this example, the contrast γ value of the resist shown in FIG. 2 and B was 8.0. The limit that can be resolved without reducing the film thickness is 0.30 μml: 1 line / space, and the pattern shape of 0.35 μml: 1 line / space does not show the tendency of the negative type head to be rounded.
As shown by G, it became steep at 90 degrees.
Also, the focus margin of 0.35 μml: 1 line / space was 1.0 μm. The contact hole could be resolved to 0.32 μm. These were confirmed by the same method as in Example 1.

Example 4 X which is a commercially available negative type chemically sensitized resist
Using P89-131 (manufactured by Shipley Far East Co., Ltd.) and TDUR-N7 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) under the same conditions as in Example 3 except for the following conditions,
By repeating the same steps, a negative resist pattern was formed.

When XP89-131 was used as a resist, the developing solution was XP89-114 developed by Shipley Far East Co., Ltd. at a prebaking temperature of 110 ° C. and a prebaking time of 90 seconds. When TDUR-N7 was used as a resist, the pre-baking temperature was 120 ° C., the pre-baking time was 90 seconds, the exposure amount was 80 mJ / cm ² , and the post-exposure bake time was 90 seconds.

As a result, XP89-13 was used as a resist.
When 1 was used, the limit at which resolution could be achieved without film loss was 0.25 μml: 1 line / space. Further, the focus margin of 0.35 μm: 1 line / space was 1.2 μm. The contact hole could be resolved to 0.30 μm. When TDUR-N7 is used as a resist, the limit of resolution without loss of film is 0.25 μm
l: 1 line / space. 0.35 μm
l: Focus margin of 1 line / space is 1.4
μm. 0.30 for contact hole
It could be resolved down to μm. These were confirmed by the same method as in Example 1.

Reference Example 5 A resist having the same composition as the resist used in Example 3 was subjected to a treatment in a gas atmosphere of hexamethyldisilazane before baking after exposure, and the gas atmosphere of hexamethyldisilazane was used. A negative resist pattern was formed by repeating the same steps as in Example 3 except that the lower processing time was set to 2.5 seconds and the irradiation was performed with an exposure amount of 50 mJ / cm ² during exposure.

FIG. 3 shows the result. In this example, the contrast γ value of the resist was 9.5. The limit that can be resolved without film loss is 0.25μ
ml: 1 line / space, 0.35 μml: 1
The pattern shape of the line / space did not show the tendency to round the head peculiar to the negative type, but became steep at 90 degrees as shown in FIG. Also, 0.30 μml: 1
The line / space focus margin was 1.0 μm. The contact hole could be resolved to 0.30 μm. These were confirmed by the same method as in Example 1.

Reference Example 6 A commercially available negative type chemically sensitized resist, XP89
-131 (manufactured by Shipley Far East Co., Ltd.) and TDUR-N7 (manufactured by Tokyo Ohka Kogyo Co., Ltd.)
A negative resist pattern was formed by repeating the same steps under the same conditions as in Reference Example 5 except for the following conditions.

When XP89-131 is used as the resist, the pre-bake temperature is 110 ° C., the pre-bake time is 90 seconds, the treatment time in a hexamethyldisilazane gas atmosphere is 5 seconds, and the exposure amount is 40 mJ / c.
m ^2, post-exposure baking time of 60 seconds, the developing solution and XP89-114 developer Shipley Far East Co., Ltd.. When TDUR-N7 is used as a resist, the pre-baking temperature is 120 ° C., the pre-baking time is 90 seconds, the processing time in a hexamethyldisilazane gas atmosphere is 5 seconds, the exposure amount is 90 mJ / cm ² , and the exposure is 90 mJ / cm ² . The post bake time was 90 seconds.

As a result, XP89-13 was used as a resist.
When 1 was used, the limit at which resolution could be achieved without film loss was 0.25 μml: 1 line / space. The focus margin of 0.30 μml: 1 line / space was 1.0 μm. The contact hole could be resolved to 0.30 μm. When TDUR-N7 is used as a resist, the limit of resolution without loss of film is 0.25 μm
l: 1 line / space. 0.30 μm
l: Focus margin of 1 line / space is 1.0
μm. 0.30 for contact hole
It could be resolved down to μm. These were confirmed by the same method as in Example 1.

Comparative Example 1 A resist having the same composition as that of the positive type chemically sensitized resist used in Example 1 was used, and the exposure was not carried out in a gas atmosphere of hexamethyldisilazane after prebaking. By repeating the same steps as in Example 1 except that the resist was irradiated at 40 mJ / cm ² , a positive resist pattern was formed.

The results are shown in FIG. 2 and FIG. In this comparative example, the contrast γ value of the resist shown in FIG. 2A was 2.8. The limit that can be resolved without reducing the film thickness is 0.32 μml: 1 line / space, and the pattern shape of 0.35 μml: 1 line / space has an inclination of 80 degrees as shown in FIG. It became a forward taper type. Further, the focus margin of 0.35 μml: 1 line / space was 0.6 μm. The contact hole could be resolved down to 0.35 μm. These were confirmed by the same method as in Example 1.

Further, as described above, a resist film was formed using a positive type chemically sensitized resist, prebaked and exposed, and then allowed to stand for 1 hour before baking after exposure. As a result, a film residue was left in the unexposed area by leaving the film untreated. In order to achieve resolution without remaining film, 4
An irradiation of 5 mJ / cm ² was required. Further, insolubilization occurred near the resist surface, resulting in a pattern shape as shown in FIGS.

Comparative Example 2 A resist having the same composition as that of the negative type chemically sensitized resist used in Example 3 was used, and the exposure was not carried out in a gas atmosphere of hexamethyldisilazane after prebaking. The negative resist pattern was formed by repeating the same steps as in Example 3 except that the irradiation was performed at 20 mJ / cm ² .

The results are shown in FIG. 2 and FIG. In this comparative example, the contrast γ value of the resist shown in FIG. 2 and B was 2.4. The limit at which resolution can be achieved without reducing the film thickness is 0.32 μml: 1 line / space, and the pattern shape of 0.35 μml: 1 line / space shows a tendency of the negative type head to be rounded, and FIG.
A 98-degree reverse taper type as shown by the following. Also,
0.35 μml: the focus margin of one line / space was 0.6 μm. The contact hole could be resolved to 0.36 μm. These were confirmed by the same method as in Example 1.

Comparative Example 3 A commercially available negative type chemically sensitized resist, X
Using P89-131 (manufactured by Shipley Far East Co., Ltd.) and TDUR-N7 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) under the same conditions as in Comparative Example 2 except for the following conditions,
By repeating the same steps, a negative resist pattern was formed.

When XP89-131 was used as the resist, the developing solution was XP89-114 developed by Shipley Far East Co., Ltd. at a prebaking temperature of 110 ° C. and a prebaking time of 90 seconds. When TDUR-N7 was used as a resist, the pre-baking temperature was 120 ° C., the pre-baking time was 90 seconds, the exposure amount was 80 mJ / cm ² , and the post-exposure bake time was 90 seconds.

As a result, XP89-13 was used as a resist.
When 1 was used, the limit at which resolution could be achieved without film loss was 0.28 μml: 1 line / space. Also, the focus margin of 0.35 μm: 1 line / space was 0.8 μm. The contact hole could be resolved down to 0.35 μm. When TDUR-N7 is used as a resist, the resolution can be reduced without reducing the film thickness.
1 line / space. 0.35 μml:
Focus margin of 0.8 μm per line / space
Met. 0.35μm for contact hole
Could be resolved. These were confirmed by the same method as in Example 1.

[0063]

According to the method for forming a resist pattern of the present invention, the pattern shape can be improved without changing the composition of the resist, and the resolution of the resist can be increased. Further, according to the method for forming a resist pattern of the present invention, a resist pattern can be formed stably.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for performing treatment with an acid quenching compound used in the present invention.

FIG. 2 is a graph showing a relationship between a remaining film ratio of a resist film obtained according to an example and a comparative example and an exposure amount.

FIG. 3 is a view showing a pattern shape of a resist film obtained by an example and a comparative example.

FIG. 4 is a view showing a pattern shape of a conventional resist film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (silicon substrate) 2 Airtight container 3 Exhaust port 4 Acid quenching compound (hexamethyldisilazane) 5 Tank containing acid quenching compound 6 Dry nitrogen 7 Resist pattern 8 Exposure part 9 Positive type chemically sensitized resist 10 Negative type chemically sensitized resist 11 Bridging

Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03F 7/38 G03F 7/075 H01L 21/027

Claims (3)

(57) [Claims] A positive or negative type chemically sensitized resist containing a photoacid generator and optionally a crosslinking agent is applied to a substrate,
After pre-baking the resist, before exposure, the substrate is treated in a gas atmosphere of an acid quenching compound to expose the resist, and the exposed portion of the resist is exposed in the case of a positive resist and not exposed in the case of a negative resist. A method for forming a resist pattern, comprising developing a resist in an exposed portion with a developer. 2. The acid quenching compound is a silyl compound such as hexamethyldisilazane, heptamethyldisilazane, diethylaminotrimethylsilane, trimethylsilyl chloride or trimethylsilyldiethylamine, or an amine compound such as ethylenediamine or merylamine. 2. The method for forming a resist pattern according to item 1. 3. The method according to claim 1, wherein the positive type chemically sensitized resist is pt
-Butoxycarbonylhydroxystyrene, triphenylsulfonium trifluoromethanesulfonate and t
2. The method for forming a resist pattern according to claim 1, wherein the resist pattern is made of butoxycarbonylated bisphenol A.