JP2000199953A - Pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To double the resolution of a resist pattern in spite of the use of an ordinary resist. SOLUTION: A resist film 12 is formed on an antireflection film 11 formed on an Si wafer 10, and the resist film 12 is patternwise exposed through a mask 14 for exposure having an L/S pattern. The exposed resist film 12 is developed with an alkali developer such that the film 12 gives a positive pattern, and then the resist film 12 is developed with such an organic solvent that the film 12 gives a negative pattern. Only the medium exposure region of the resist film 12 is left, and the objective L/S pattern whose pitch is half that of the mask pattern is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming technique for forming a fine pattern required for manufacturing a semiconductor device and the like, and more particularly, to a method for forming a resist pattern by improving a resist developing process, and The present invention relates to a pattern forming method using the same.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of semiconductor devices, optical lithography has been used to form fine patterns on wafers. A conventional method of forming a resist pattern in photolithography will be described with reference to FIG.

[0003] Using a reduction exposure apparatus, the repetition pitch is P
An exposure mask having a line-and-space (L / S) pattern (converted to a value on the wafer) is used, and the pattern of this mask is transferred onto the wafer at an exposure amount E. FIG. 12A shows an image intensity distribution of the mask 90 on the wafer surface.

In general, there are two types of resist films formed on a wafer: a positive type in which exposed portions are melted during development and a negative type in which unexposed portions are melted. The ideal γ curve is shown in FIG. And (c). Exposure mask 90
The resist film having the image intensity distribution obtained after passing through is developed in accordance with the γ curve, so that a resist pattern 91 is formed on the wafer 92 as shown in FIG.

[0005] The fundamental limit resolution is determined by the exposure wavelength λ and the lens numerical aperture NA. In normal illumination, when a binary mask is used, in a pattern having a pitch of λ / NA or less, since ± 1st-order diffracted light is blocked by the aperture stop on the pupil surface of the projection lens, only the 0th-order light reaches the wafer surface. I can't image. When a resist having a general γ curve is used, the limiting resolution is determined by the exposure apparatus.

On the other hand, a method has been proposed in which the resolution is doubled by using a resist having a γ characteristic as shown in FIG. 13 (a) or (b) (JP-A-8-250395). Gazette). In this method, an L / S pattern can be formed by making the resist soluble (or insoluble) at a large exposure area and a small exposure area, and insoluble (or soluble) at an intermediate exposure area. .

However, this type of method has the following problems. That is, FIG.
It is extremely difficult to create a sensitivity characteristic like No. 3, and it is difficult to actually realize a resist having such characteristics. Even if it can be realized, it is necessary to use a special material, and there is also difficulty in selecting a material, which is considered to cause an increase in manufacturing cost.

[0008]

As described above, conventionally, the resolution of a resist pattern can be doubled by using a special resist as shown in FIG. 13, but this kind of resist is realized. It is difficult, and even if it can be realized, it is disadvantageous in terms of cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist capable of improving the resolution of a resist pattern by a factor of two in spite of using a normal resist. It is to provide a pattern forming method and a pattern forming method.

[0010]

(Structure) In order to solve the above problem, the present invention employs the following structure.

That is, according to the present invention, in a method for forming a resist pattern, a step of forming a resist film on a substrate to be processed, a step of exposing the resist film to a desired pattern,
Developing the resist film using a first developer such that the resist film obtains a positive pattern, and developing the resist film using a second developer such that the resist film obtains a negative pattern And a step of performing

Here, preferred embodiments of the present invention include the following. (1) The first developing solution dissolves a region of the resist film where the exposure amount E> E2, and the second developing solution dissolves the exposure amount E of the resist film.
<E1 is melted, and the exposure amount E becomes E1 ≦ E ≦ E
2 (however, the resist film is left only in a region included in the range of E1 <E2). Here, the maximum exposure amount in the pattern portion of the resist film is larger than E2, and the minimum exposure amount in the non-pattern portion is smaller than E1.

(2) A high polarity solution is used as the first developer and a low polarity solution is used as the second developer. (3) Use an aqueous alkaline solution as a highly polar solution. (4) Use an organic solvent as a low-polarity solution. (5) Use chemically amplified resist.

(6) A reticle on which a pattern having a period such that only the zero-order diffracted light reaches the substrate to be processed is used. (7) Use a reticle on which a pattern whose repetition cycle is λ / NA (1 + σ) or less is arranged. Where λ, N
A and σ are an exposure wavelength of an exposure apparatus, a lens numerical aperture, and a coherence factor, respectively.

Further, according to the present invention, in a pattern forming method for forming a desired pattern on a substrate to be processed, after forming a resist pattern by the above-described resist pattern forming method, a base is processed using the resist pattern as a mask. And a step of embedding a desired film in a groove formed by processing.

Further, according to the present invention, in a pattern forming method for forming a desired pattern on a substrate to be processed, a resist pattern is formed by the above-described resist pattern forming method, and then a base is processed using the resist pattern as a mask. Performing a step of removing the resist pattern, forming a resist film again after removing the resist pattern, and exposing the re-formed resist film to remove unnecessary patterns.

Further, the present invention is characterized in that a semiconductor device or a precision component is manufactured by using the above-described method for forming a resist pattern.

(Function) The resist becomes positive type in the developing solution A (first developing solution) and negative type in the developing solution B (second developing solution), and the γ curve is shown in FIG. 1 (a). Is assumed. Here, when the exposure amount E is in the range of E1 <E <E2, the resist becomes insoluble regardless of which of the developing solutions A and B is used.

As shown in FIG. 1B, the exposure mask 2 of the L / S pattern is exposed with the exposure light 1 at a predetermined exposure amount, and if the exposure amount distribution on the resist surface becomes as shown in FIG. ,
By developing sequentially using the developing solutions A and B (the order may be reversed), the resist is dissolved at the exposure amounts E <E1 and E> E2, and the resist remains at the exposure amounts E1 <E <E2. As a result, FIG.
As shown in (c), an L / S resist pattern 3 having a half pitch of the pattern of the exposure mask 2 is obtained on the wafer 4.

As shown in FIG. 1 (d), the relationship between the γ curves when using the developing solutions A and B is such that when there is no region in which any of the developing solutions is insoluble, the above-mentioned effect is obtained. Cannot be obtained.

The process of the present invention can be applied to any exposure light source. In particular, MUV for g-line, i-line, etc.
Exposure, KrF, DUV exposure of ArF, etc., VUV such as F ₂
Effective for optical lithography like exposure, but X
The present invention is also applicable to lithography using a line, EB, ion beam, or the like.

A general positive resist becomes soluble in an alkaline developing solution by decomposing a dissolution inhibitor, which is a non-polar group, by exposure to produce a polar group such as a hydroxyl group or a carboxyl group. Here, when the developing solution is changed from an alkaline one to a non-polar one, for example, a specific organic solvent or the like, an unexposed portion dissolves and an exposed portion remains. That is, a negative pattern can be obtained.

Therefore, in the developing process, when a low-polarity solution that dissolves a non-polar group and a high-polarity solution that dissolves a polar group are sequentially developed, a portion containing a large amount of non-polar groups in the resist film (the amount of exposure A low or high area) and a portion having a large amount of polar groups (high or low exposure amount) are dissolved, and a portion where a polar group and a non-polar group are mixed (corresponding to an intermediate exposure amount region) is dissolved. It remains without dissolving in.

As a highly polar solution, an alkaline aqueous solution which is a general resist developer is suitable. For example, an aqueous solution of potassium hydroxide or an aqueous solution of tetramethylammonium hydride (TMAH) can be used. These normalities should be adjusted so as to be appropriate for the resist to be used, but a commercially available developer such as MF312 (manufactured by Shipley) may be diluted with pure water.

Various organic solvents are considered to be suitable as the low-polarity solution. For example, ethers such as diethyl ether, tetrahydrofuran, and anisole, and ketones such as acetone, methyl isobutyl ketone, and cyclohexanone are exemplified. A mixture of several organic solvents may be used, and it is necessary to experimentally find the optimum one for the resist to be used.

A chemically amplified resist widely used as a positive resist for DUV exposure, such as KrF or ArF, has a low-polarity functional group (eg, polyvinylphenol) that makes a part of the side chain insoluble in an alkali developing solution. A resin substituted with a dissolution-inhibiting group, for example, a t-butoxycarbonyl group, a t-butoxycarbonylmethyl group, an acetal group, or the like is used as the resin. The photosensitizer uses a so-called acid generator that generates a strong acid upon exposure, for example, an onium salt, and this strong acid serves as a catalyst in PEB to decompose the dissolution inhibiting group.

That is, before and after exposure, the resist resin changes from a low polarity state to a high polarity state. Therefore, if a low-polarity solution is used, the unexposed portion dissolves, and if a high-polarity solution is used, the exposed portion dissolves. Therefore, a general chemically amplified resist is considered to be one of the most suitable materials.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) FIG. 2 shows a first embodiment of the present invention.
FIG. 4 is a process cross-sectional view showing a method for forming a resist pattern according to the embodiment.

First, as shown in FIG. 2A, a chemically amplified resist is applied on a substrate to be processed in which an organic antireflection film (AR3: manufactured by Shipley) 11 having a thickness of 60 nm is formed on a Si wafer 10. Then, pre-baking was performed at 100 ° C. for 90 seconds to form a resist film 12 having a thickness of 200 nm. The resist used was a resin made of a copolymer of pt-butoxycarbonylmethoxystyrene and 4-hydroxystyrene, and triphenylsulfonate as an acid generator.

Next, as shown in FIG.
Using a NA KrF excimer exposure apparatus, wavelength 248 nm
The exposure mask 14 having a 200 nm L / S pattern (converted to the dimensions on the wafer) was transferred to the resist film 12 by the exposure light 13.

Next, a post-exposure bake (PEB) at 100 ° C./90 seconds was performed, and developed with a 0.1 N tetramethylammonium hydride (TMAH) aqueous solution for 30 seconds. Subsequently, the substrate was rinsed with pure water and spin-dried. As shown in FIG. 1C, only the region of the resist film 12 where the exposure amount was sufficiently large was removed by the first developer.

Then, a mixed solution of anisole and methyl isobutyl ketone (MIBK) (mixing ratio: 4: 1) was added to the solution.
After developing for 0 second, rinsing was performed with anisole. As shown in FIG. 1D, only the region of the resist film 12 where the exposure amount was sufficiently small was removed by the second developer.

As described above, in the present embodiment, the resist 12 in the region with a large exposure amount is removed by the first development processing using the TMAH aqueous solution, and the resist 12 in the region with the small exposure amount is removed by the second development with the mixed solution of anisole / MIBK. 12 was removed. By adjusting the developing time, the resist 12 can be left only in the intermediate exposure amount area. 2 each
As a result of creating a fine space by performing the development twice, a 100 nm L / S pattern having a half pitch of the exposure mask pattern could be obtained.

For comparison, in order to try to form a 100 nm L / S pattern by the conventional technique, an exposure mask having a 100 nm L / S was transferred using the same exposure amount and resist. After the same process as in the present embodiment up to PEB, 60% is added with 0.27N TMAH aqueous solution.
After developing for 100 seconds, the 100 nm L / S pattern was not resolved.

As described above, according to the present embodiment, the resist film 12 is developed with the first developer which becomes positive type, and then the resist film 12 is developed with the second developer which becomes negative type. By doing so, only the intermediate exposure amount region can be left, and an L / S pattern having a half pitch of the mask pattern can be formed. In this case, it is not necessary to use a special resist, and it can be realized at low cost by using a normal resist. That is, despite the use of a normal resist, the resolution of the resist pattern can be doubled, and its usefulness is great.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
FIG. 4 is a process cross-sectional view showing a method for forming a resist pattern according to the embodiment.

First, as shown in FIG. 3A, a chemically amplified resist is applied on a substrate to be processed in which an organic antireflection film (AR3: manufactured by Shipley) 21 having a thickness of 60 nm is formed on a Si wafer 20. Then, prebaking was performed at 100 ° C. for 90 seconds to form a resist film 22 having a thickness of 100 nm. The resist used was a resin made of a copolymer of pt-butoxycarbonylmethoxystyrene and 4-hydroxystyrene, and triphenylsulfonate as an acid generator.

Next, as shown in FIG.
Using a NA KrF excimer exposure apparatus, wavelength 248 nm
The pattern of the exposure mask 24 was transferred to the resist film 22 by the exposure light 23. The exposure mask 24 is shown in FIG.
As shown in (a), a halftone mask (transmittance 6%, phase difference 180 degrees) is arranged in a checkerboard pattern at a pitch of 400 nm. Here, 26 is a halftone area, and 27 is a transparent area.

Next, PEB was performed at 100 ° C./90 seconds, and developed with a 0.1 N aqueous TMAH solution for 30 seconds. Subsequently, the substrate was rinsed with pure water and spin-dried. As shown in FIG. 3C, only the region of the resist film 22 where the exposure amount was sufficiently large was removed by the first developer.

Next, the film was developed with a mixed solution of anisole and MIBK (mixing ratio: 4: 1) for 60 seconds, and rinsed with anisole. FIG. 3 shows the second developer.
As shown in (d), only the region of the resist film 22 where the exposure amount was sufficiently small was removed.

As described above, in the present embodiment, the resist 22 in the region with a large exposure amount is removed by the first development processing with the TMAH aqueous solution, and the resist 22 in the region with the small exposure amount is removed by the second development with the mixed solution of anisole / MIBK. 22 was removed. By adjusting the developing time, the resist 22 can be left only in the intermediate exposure amount area. As a result of creating fine holes in each of the two developments, FIG.
(B) As shown in FIG.
An array of m contact holes 29 was obtained.

For comparison, a pattern forming method according to the conventional method described in the first embodiment was also tested, but a contact hole array similar to that of the present embodiment could not be formed.

As described above, according to the present embodiment, the resist film 22 is developed with the first developer which becomes positive, and then the resist film 22 is developed with the second developer which becomes negative. By doing so, only the intermediate exposure amount region can be left, and a checkerboard lattice pattern having a half pitch of the mask pattern can be formed. In this case, it is not necessary to use a special resist, and it can be realized at low cost by using a normal resist. Therefore, the same effect as in the first embodiment can be obtained.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
FIG. 5 is a process cross-sectional view showing a pattern forming method according to the embodiment.

First, as shown in FIG. 5A, a thermal oxide film (100 nm) 31 and a TEOS (2
(00 nm) A film 32 was formed. Subsequently, as shown in FIG. 5B, after forming an organic antireflection film (AR3: manufactured by Shipley) 33 having a thickness of 60 nm, a chemically amplified resist is applied and prebaked at 100 ° C./90 seconds. , 200n
An m-thick resist film 34 was formed. The resist used was
The resin is a copolymer of pt-butoxycarbonylmethoxystyrene and 4-hydroxystyrene, and the acid generator is triphenylsulfonate.

Next, using a 0.6 NA KrF excimer exposure apparatus (light source wavelength: 248 nm), the pattern of the exposure mask 35 as shown in FIG.
Transferred to The mask 35 has an L / S pattern having a 400 nm cycle in the area A, a large area punching pattern as a pad section in the area B, and an L / S pattern having a 200 nm cycle for forming a large area resist remaining pattern in the area C. are doing.

Next, PEB is performed at 100 ° C. for 90 seconds, and a resist film 34 is formed using a 0.1 N TMAH aqueous solution.
Was developed for 30 seconds. Subsequently, the substrate was rinsed with pure water and spin-dried. Thereby, as shown in FIG. 5C, only the region of the resist film 34 where the exposure amount was sufficiently large was removed.

Next, the resist film 34 was developed with a mixed solution of anisole and MIBK (mixing ratio 4: 1) for 60 seconds, and rinsed with anisole. This allows
As shown in FIG. 5D, only the region of the resist film 34 where the exposure amount was sufficiently small was removed.

FIG. 6B shows a resist pattern formed by the above process. In the figure, reference numeral 34 denotes a region where the resist film remains, and 36 denotes a region where the resist film has been removed.
In the present embodiment, the resist film 34 is dissolved at portions where the exposure amount is large and small, and the resist film 34 remains at an intermediate exposure amount. Therefore, the region A has a 200 nm period L
/ S resist pattern, and a resist removal pattern is formed in region B.

The point is a region C. In this case, since a fine L / S pattern that gives only the 0th-order diffracted light is arranged on the wafer surface, the resist film 34 is uniformly given a certain exposure amount. Can be The exposure mask 35 is so exposed that the resist film 34 remains after the second development.
Since the opening width of the pattern is adjusted, the resist film 34 remains on the entire surface in the region C.

Next, as shown in FIG. 5E, the anti-reflection film 33 and the TEOS film 3 are formed using the resist film 34 as a mask.
2 was selectively etched. Thereafter, as shown in FIG. 5F, the resist film 34 and the antireflection film 33 were peeled off.

Next, as shown in FIG.
The Al formed in the groove formed in the S film 32 by sputtering.
The film 37 was buried, and the wafer surface was further polished by a chemical polishing method (CMP) until the TEOS film 32 was exposed as shown in FIG. Then, the TEOS film 32 was removed.

By passing through the above-described inversion process, as shown in FIG. 6C, an Al pattern inverted from the resist pattern of FIG. 6B is obtained. The pattern of the Al film 37 is formed on the portion 36 without the resist film 34, and by adopting this process, a TEG (Test Element Group) pattern composed of a fine L / S pattern can be formed. Since the conventional method cannot form a 200 nm pitch L / S as described in the first embodiment,
A TEG pattern as in the present embodiment could not be made.

Here, the reason why the resist pattern remains in the region C as shown in FIG. 6B will be further described. When only the intermediate exposure amount region is left, the resist is left at a portion corresponding to the edge of the mask pattern. Therefore, a device is required to form a wide-resist remaining pattern. The exposure amount corresponding to the edge of the exposure mask pattern may be given over a wide range on the wafer surface, and the following method can be considered.

In the optical lithography using a general reduction optical system, as described in the related art, in an L / S pattern having a small pitch to some extent, high-order diffracted light cannot pass through the lens, so that it is formed on the wafer surface. You can no longer image. However, since the 0th-order diffracted light reaches the wafer surface,
It is possible to give a uniform exposure amount over a wide range. The exposure amount given to the wafer surface can be adjusted by changing the space width of L / S.

FIG. 7 shows a wavelength of 248 nm, NA = 0.6,
Under the exposure condition of σ = 0.75, 200 nm pitch L / S
2 shows the space width dependence of the effective exposure amount given on the wafer surface when the exposure amount set in the exposure apparatus is 20 mJ. From this, it is possible to form a large-area resist residue pattern by previously knowing the exposure range in which the resist used is insoluble and adjusting the space width so as to give the exposure range.

In a general exposure apparatus (light source wavelength λ, lens numerical aperture NA, coherence factor σ), when a binary mask is used, only the 0th-order diffracted light in the L / S pattern having a pitch of λ / NA (1 + σ) or less is used. Does not reach the surface. Therefore, in order to form a wide range of resist residue, an L / S pattern having a pitch smaller than this may be used.

As described above, according to the present embodiment, the mask is developed by performing the development twice, that is, the positive development processing and the negative development processing, as in the first and second embodiments. An L / S pattern having a fine pitch of half the pitch of the pattern can be formed. In addition, in the present embodiment, since a large-area resist leaving pattern can be formed, the applicable range can be expanded.

(Fourth Embodiment) As described in the third embodiment, when only the intermediate exposure area is left, the resist is left in the area corresponding to the edge of the mask pattern. Only a closed loop resist pattern can be formed. Therefore, in this embodiment, a method for forming a broken line pattern will be described.

FIGS. 8 and 9 are views for explaining a pattern forming process according to the fourth embodiment. FIG. 8 is a plan view and FIG. 9 is a sectional view. FIG. 9 shows FIG.
(C) corresponds to a cross section taken along the line AA ′.

First, as shown in FIG.
A resist pattern 42 as shown in FIG. 8B is formed on the base film 43 in the same manner as in the first to third embodiments, using an exposure mask having 0 and a transmission portion 41.

Next, as shown in FIG. 9A, after processing the base film 43 on the Si wafer 44 using the resist 42 as a mask, another film 45 is buried and formed as shown in FIG. 9B. I do. Subsequently, as shown in FIG. 9C, the excess film 45 is removed by CMP or the like to expose the base film 43. Next, as shown in FIG. 9D, if etching is performed so as to selectively remove the base film 43, FIG.
As shown in (c), a cut pattern composed of the film 45 can be formed on the Si wafer 44.

As described above, in the present embodiment, as in the first to third embodiments, it is possible to form an L / S pattern having a fine pitch of half the pitch of the mask pattern, and of course, once forming the resist. By transferring the pattern to the base and employing an image reversal process such as a damascene, it is possible to form a cut line pattern.

(Fifth Embodiment) The present embodiment is a method of forming a cut line pattern by a method different from that of the fourth embodiment. 10 and 11 are views for explaining a pattern forming process according to the fifth embodiment. FIG. 10 is a sectional view, and FIG. 11 is a plan view. FIG. 10 corresponds to a cross section taken along line BB ′ of FIG. 11B.

First, similarly to the fourth embodiment,
The underlying film is processed using the resist pattern as a mask. FIG. 1 corresponds to the cross section BB ′ of FIG. 8B in this state.
0 (a), a base film 53 is formed on the Si wafer 54, and the base film 53 is patterned by a resist pattern.

Next, as shown in FIG. 10B, a resist film 58 is applied again, and a pattern of an exposure mask for removing an unnecessary pattern is transferred. An exposure mask for removing this extra pattern is shown in FIG.
As shown in FIG. 7, an opening is formed only in a portion corresponding to an extra pattern portion, which includes a light shielding portion 50 and a light transmitting portion 51.

Next, as shown in FIG. 10C, the resist film 58 is developed by a usual method.
As shown in (d), the underlying film 53 is etched using the remaining resist film 58 as a mask. As a result, FIG.
As shown in (b), a cut line pattern composed of the base film 53 can be formed on the Si wafer 54.

As described above, in this embodiment, as in the first to third embodiments, not only the L / S pattern having a fine pitch of half the pitch of the mask pattern can be formed, but also unnecessary patterns can be formed. By using an exposure mask for removing a pattern region, a cut line pattern can be formed.

The present invention is not limited to the above embodiments. In the embodiment, the first positive type is used.
The development is performed once each using the developer of the formula (1) and the second developer which is a negative type. By repeating this process, a higher resolution can be obtained. Further, the order of development with the first developer and the second developer may be either.

In the embodiment, KrF
Although an excimer exposure apparatus was used, the exposure light source is not limited to ArF and can be changed as appropriate. For example, MUV exposure such as g-line and i-line, DUV exposure such as KrF and ArF, F ₂
Can be effectively applied to photolithography like VUV exposure. Further, the present invention can be applied to lithography using X-ray, EB, ion beam, and the like.

In addition, various modifications can be made without departing from the spirit of the present invention.

[0073]

As described above in detail, according to the present invention, both the positive type development and the negative type development are performed on the resist film, and only the intermediate exposure area is left, so that a special resist or the like can be obtained. Thus, ultra-fine processing can be realized more than before without using. For this reason, it becomes possible to manufacture semiconductor devices such as memory devices and logic devices and various precision components with higher integration or higher density.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a principle of obtaining a resolution twice as large as a mask pattern according to the present invention.

FIG. 2 is a sectional view showing a step of the method for forming a resist pattern according to the first embodiment.

FIG. 3 is a process sectional view showing a method for forming a resist pattern according to a second embodiment.

FIG. 4 is a plan view illustrating a relationship between an exposure mask and a transfer pattern used in a second embodiment.

FIG. 5 is a process cross-sectional view showing a pattern forming method according to a third embodiment.

FIG. 6 is a plan view showing a relationship between an exposure mask and a transfer pattern used in a third embodiment.

FIG. 7 is a characteristic diagram showing a space width dependency of an effective exposure amount given on a wafer surface.

FIG. 8 is a plan view showing a relationship between an exposure mask and a transfer pattern used in a fourth embodiment.

FIG. 9 is a process cross-sectional view showing a pattern forming method according to the fourth embodiment.

FIG. 10 is a process sectional view illustrating the pattern forming method according to the fifth embodiment;

FIG. 11 is a plan view showing a relationship between an exposure mask and a transfer pattern used in a fifth embodiment.

FIG. 12 is a schematic diagram for explaining a conventional problem and showing a relationship between an exposure mask and a transfer pattern.

FIG. 13 is a view showing an example of a special resist having a sensitivity characteristic of making a resist insoluble or soluble in an intermediate exposure amount region.

[Explanation of symbols]

 Exposure light 2,14,24,35 Exposure mask 3 Resist pattern 4,10,20,30,44,54 Si wafer 11,21,33 Antireflection film 12,22, 34, 42, 58 ... resist film 26 ... halftone region 29 ... contact hole 27, 41, 51 ... transparent region 31 ... thermal oxide film 32 ... TEOS film 36 ... region from which the resist film has been removed 37 ... Al film 40, 50 … Light-shielding regions 43, 53… underlying film 45… different films

 ────────────────────────────────────────────────── ─── Continued on front page F term (reference) 2H025 AA02 AB16 AC01 AC04 AC05 AC06 AC07 AD07 BE00 BE10 BG00 CB17 CB41 CB45 CB52 DA18 EA04 FA03 FA15 FA16 FA39 FA41 5F046 AA02 AA07 AA08 AA09 AA10 BA08 EA02 LA00

Claims (6)

[Claims] A step of forming a resist film on a substrate to be processed; a step of exposing a desired pattern to the resist film;
Developing the resist film using a first developer such that the resist film obtains a positive pattern, and developing the resist film using a second developer such that the resist film obtains a negative pattern Forming a resist pattern. 2. The method according to claim 1, wherein the first developing solution comprises an exposure amount E of the resist film.
> E2 is dissolved, and the second developer dissolves the region of the resist film where the exposure amount E <E1. 2. The method according to claim 1, wherein the resist film is left only in the included region. 3. The method according to claim 1, wherein a high polarity solution is used as the first developing solution, and a low polarity solution is used as the second developing solution. 4. The reticle according to claim 1, wherein, when exposing a desired pattern to the resist film, a reticle having a pattern having a period such that only zero-order diffracted light reaches the resist film is used. A method for forming a resist pattern. 5. A step of forming a resist pattern by the method for forming a resist pattern according to any one of claims 1 to 4, and then processing an underlayer using the resist pattern as a mask.
Embedding a desired film in a groove formed by processing. 6. A step of forming a resist pattern by the method for forming a resist pattern according to any one of claims 1 to 4, and then processing a base using the resist pattern as a mask.
A pattern forming method, comprising: a step of forming a resist film again after removing the resist pattern; and a step of performing exposure for removing an unnecessary pattern on the reformed resist film.