JPH11214510A - Method for self alignment pattern formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent miss alignment with a base pattern. SOLUTION: A second film consisting of substance 6 deactivating acid is formed on a first film consisting of an interlayer insulating film 4 on a base substrate 1 where a gate electrode 3 is made and substance 5 not deactivating acid accumulated on the interlayer insulating film 4, and the second film is patterned, using a first mask in line form along the gate electrode 3. Furthermore, a chemical width increasing positive resist 21 is applied on the second film in line form being made, and it is exposed to light, using a second line-form mask being made to cross the first mask, and resist 21 in exposure region excluding the periphery of the second film is converted into a soluble layer, and a contact hole is made by etching them from above the resist pattern made by the exposure to the first film and the interlayer insulating film 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-aligned pattern forming method for providing a highly accurate lithography process without misalignment by forming a self-aligned pattern.

[0002]

2. Description of the Related Art In a highly integrated semiconductor device represented by a DRAM in which a memory cell is constituted by one MOS transistor and one capacitor, the degree of integration has been increased by miniaturizing a minimum processing size. Where DRA
A pattern forming step of forming a contact hole pattern connecting a transistor and a wiring layer with an M device or the like will be described with reference to FIG.

First, on a base substrate (silicon substrate) 1,
Through a thin gate oxide film 2 made of SiO ₂ or the like, po
Gate electrode material 3a, 3 made of ly-Si / WSi or the like
b and Si covering the upper surfaces of the gate electrode materials 3a and 3b.
An insulating film 3c made of N or the like is deposited, and a linear gate electrode 3 is formed by RIE.

Then, an interlayer insulating film 4 is deposited on the base substrate 1 on which the plurality of gate electrodes 3 are formed. (FIG. 11
(A)). Next, a hole-shaped mask 121 (121a) having a width smaller than the width between the gate electrodes 3 as shown in FIG.
Exposure is performed using a light-shielding portion, and 121b is a light-transmitting portion, and a contact hole is formed by etching after forming a resist pattern (FIG. 11B). Then, by embedding a conductive material in the contact hole, it is electrically connected to a diffusion layer (not shown) in the underlying substrate 1 formed immediately below the contact hole.

[0005] FIG. 1 shows a problem relating to the alignment between the mask and the wafer when the overlay exposure is performed by the above steps.
1 (c) and (d). FIG. 11C shows the mask 12.
This is an example in which the position shift of No. 1 has occurred. The contact hole is in contact with the gate electrode 3 due to a shift between the formation position of the gate electrode 3 and the pattern formation position of the contact hole pattern. When a conductive material is buried in the contact hole, the gate electrode 3 and the contact layer are short-circuited, so that normal operation as a device becomes difficult. Also,
FIG. 11D shows a change in the proper exposure amount and a change in process conditions.
In some cases, a short circuit occurs in the pattern as shown in FIG.
Also in this case, since the gate electrode is in contact with both side walls of the contact hole, the gate electrode and the contact layer are short-circuited, and normal operation becomes difficult.

[0006]

In the above-described conventional pattern forming method, the overlay exposure accuracy required with the miniaturization of the pattern becomes strict. Matching is a problem. In performing such overlay exposure, when a certain pattern is aligned and a different pattern is formed, a positional shift occurs or the pattern is short-circuited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a self-aligned pattern forming method for preventing misalignment.

[0008]

According to a first aspect of the present invention, there is provided a method for forming a self-aligned pattern, the method comprising: forming a second film made of a material capable of deactivating acid on a first film made of a material which does not deactivate acid;
Forming a plurality of line patterns of the second film by selectively removing the second film; and forming a chemically amplified positive electrode on the first film and the second film. Applying a resist, exposing the first film and the second film to a linear pattern crossing the line length direction of the second film, excluding the periphery of the second film Transforming the resist in the exposed area into a solubilized layer, developing the exposed chemically amplified positive resist, and using the resist pattern formed by the development as a mask to form the first resist.
And etching the film.

According to a second aspect of the present invention, in the method of forming a self-aligned pattern, a second film made of a material that deactivates an acid is formed on a first film made of a material that does not deactivate an acid. Forming a plurality of line patterns of the second film by selectively removing the second film to remove the first film; and forming a plurality of line patterns of the second film on the first film and the second film. Applying a chemically amplified negative resist, and exposing the first film and the second film using a line-shaped pattern intersecting with a line length direction of the second film; Transforming the resist in the exposed region excluding the periphery of the film into an insolubilized layer, developing the exposed chemically amplified negative resist, and using the resist pattern formed by the development as a mask to form the first film And a step of etching the second film. And wherein the Rukoto.

Further, the method of forming a self-aligned pattern according to the present invention does not deactivate an interlayer insulating film deposited on a substrate having a plurality of linear gate electrodes formed thereon and an acid deposited on the interlayer insulating film. Forming a second film made of a substance that deactivates an acid on the first film made of a substance; removing the second film to expose the first film; Forming a plurality of line patterns of a second film located immediately above the first film, applying a chemically amplified positive resist to the first film and the second film, and performing a gate length direction of the gate electrode. Exposing the chemically amplified positive resist to the remaining second film by exposing using a linear second mask having intersecting light-transmitting regions; and The substrate is exposed using And characterized by being a step of forming a contact hole by etching to.

Further, the method of forming a self-aligned pattern according to the present invention does not deactivate a conductive material deposited on a substrate having a plurality of linear gate electrodes formed thereon and an acid deposited on the conductive material. Forming a second film made of a substance that deactivates an acid on the first film made of a substance; removing the second film to expose the first film; Forming a plurality of line patterns of a second film positioned immediately above the first film, applying a chemically amplified negative resist to the first film and the second film, and performing a gate length direction of the gate electrode. Exposing using a line-shaped second mask having intersecting light-transmitting regions to cause a cross-linking reaction of the chemically amplified negative resist while leaving a peripheral portion of the second film; and Developing the negative resist; Characterized by comprising the formed resist pattern and a step of the substrate as a mask to etch the first layer and the conductive material so as to expose the.

Preferred embodiments of the present invention are as follows. (1) SiN, TiN, A
l, BPSG, TEOS, poly-Si, etc. are suitable, but the material species is not limited as long as it has the action.

(2) As a substance which does not deactivate acid, ba
se Si, thermal SiO ₂ , fully annealed CVD-
Although SiO ₂ or the like is suitable, the substance type is not limited as long as it has the action.

(Function) In the present invention, a chemically amplified positive resist is applied to a linear pattern composed of a substance that deactivates an acid, and a linear mask formed so as to intersect this line pattern is used. Exposure is performed to selectively adsorb the chemically amplified positive resist to the acid deactivating substance, and etching is performed using the formed resist pattern as a mask.

[0015] Thus, a new pattern not in the mask can be formed. Further, since the etching is performed using the chemically amplified positive resist adsorbed on the substance that deactivates the acid as a mask, a pattern can be formed in a self-aligned manner, and pattern displacement does not occur. Furthermore, since it is not necessary to use a hole pattern mask, the resolution is improved.

In the present invention, a chemically amplified negative resist is applied to a linear pattern formed of a substance that deactivates an acid, and a linear mask formed so as to intersect this line pattern is used. Exposure causes the chemically amplified negative resist to selectively stop the cross-linking reaction in the vicinity of the substance that deactivates the acid, and is etched using the resist pattern thus formed as a mask.

As a result, a new pattern not present in the mask can be formed. Further, since etching is performed using a chemically amplified negative resist in which a crosslinking reaction is stagnant selectively by a substance that deactivates an acid as a mask, a pattern can be formed in a self-aligned manner, and pattern displacement does not occur. Furthermore, since it is not necessary to use a hole pattern mask, the resolution is improved.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 3 are views for explaining a self-aligned pattern forming method according to a first embodiment of the present invention, in which a contact hole is formed between lines using a dual damascene process. It is a figure showing a process. This embodiment shows a case where a contact hole pattern connecting a transistor and a wiring layer is formed in a DRAM device or the like.
FIG. 4 shows a perspective view and a top view of a main step in the pattern forming step shown in FIGS. 1 to 3, and FIG. 5 is a view showing a mask pattern used for pattern formation in the same embodiment. .

First, a gate electrode material 3a made of poly-Si / WSi or the like is placed on a base substrate (silicon substrate) 1 made of Si or the like, on which a thin gate oxide film 2 made of SiO ₂ or the like and having a thickness of 10 nm covers the upper surface. 3b and an insulating film 3 made of SiN or the like covering the upper surfaces of the gate electrode materials 3a and 3b.
c is deposited by a CVD method or the like. Gate electrode material 3a,
3b and the insulating film 3c have a thickness of 100 nm and 5 nm, respectively.
5 nm and 150 nm. Thereafter, the gate electrode materials 3a, 3b and the insulating film 3c are etched using a lithography method and an anisotropic etching technique such as RIE (reactive ion etching) until the gate oxide film 2 is exposed, thereby forming a plurality of lines. Are formed at intervals of 0.3 μm. This etching can be performed until the underlying substrate 1 is exposed.

Then, on the base substrate 1 on which the plurality of gate electrodes 3 are formed, an interlayer insulating film 4 such as BPSG is deposited so as to have a thickness of 100 nm on the gate electrodes 3. Then, for example, SiO ₂ or the like
The substance 5 which does not deactivate the acid is 100 nm thick by a CVD method or the like.
And annealed (FIG. 1).
(A)). Next, CV is applied on the substance 5 which does not deactivate the acid.
A material 6 for inactivating an acid made of SiN or the like is deposited to a thickness of 100 nm by a method D or the like (FIG. 1).
(B)).

The material 6 for inactivating the acid is formed on a line having the same width and pitch as the linear gate electrode 3 formed thereunder, and the material 6 for inactivating the acid is located immediately above the gate electrode 3. Lithography and anisotropic etching technology such as RIE (dry etching)
Is patterned using. Specifically, as shown in FIG. 5A, exposure is performed using a line-and-space pattern mask 51 having a light-shielding portion 51a made of Cr or the like and a light-transmitting portion 51b made of quartz or the like. A pre-bake at 100 ° C. for 60 seconds is performed to form a resist pattern corresponding to the gate electrode 3. Then, using the resist pattern as a mask, the substance 6 for deactivating the acid is dry-etched,
Further, a line & space pattern made of the substance 6 for deactivating the acid by stripping the resist is formed (FIG. 1).
(C)). FIG. 4A shows a perspective view after the line & space pattern is formed. As can be seen from FIG. 4A, the gate electrode 3 and the acid deactivating substance 6 are formed in the same direction, width and pitch.

Next, a chemically amplified positive resist 21 (AP) is formed on the line-formed substance 6 for inactivating the acid.
EX-E (Shipley) is applied to a thickness of about 250 nm (FIG. 2D).

Next, a chemically amplified positive resist 21 is coated and a contact hole is formed between the line patterns made of the substance 6 for inactivating the acid, as shown in FIG.
A line pattern orthogonal to the mask 7 shown in FIG. 5A is arranged, and a light shielding portion 52a and a light transmitting portion 52b shown in FIG.
KrF excimer stepper N using a mask 52 made of
Exposure is performed using SR S201A (manufactured by Nikon Corporation).

At the time of this exposure, the resist 21 is dissolved by a decomposition reaction in the linear light transmitting region of the chemically amplified positive resist 21. Further, at the time of this exposure, an acid is generated in the resist 21 to accelerate the dissolution reaction of the resist 21. However, near the surface of the acid deactivating substance 6 formed in the lower layer of the chemically amplified positive resist 21, the acid generated in the resist 21 is deactivated by the acid deactivating substance 6, and the resist dissolution reaction Stagnates. On the other hand, on the surface of the substance 5 that does not deactivate the acid, there is no deactivation of the acid near the substance 6 that deactivates the acid, and a sufficient dissolution reaction proceeds. Therefore, only in the vicinity of the surface of the substance 6 for inactivating the acid, the chemically amplified positive resist 21 selectively adsorbs to the substance 6 for inactivating the acid, and the absorbed amount remains as the insolubilized layer 22 (FIG. 2).
(E)).

The detailed operation of the above-described chemically amplified positive resist will be described. As the substance to be modified by the acid reaction, for example, a mixture of a substance obtained by partially replacing polyvinylphenol with a t-butoxycarbonyl group and an onium salt serving as an acid generator is used. This is the composition of a general chemically amplified positive resist. In such a chemically amplified positive resist, an acid generated from an acid generator by ultraviolet rays decomposes a t-butoxycarbonyl group by a catalytic reaction to increase a dissolution rate in an alkaline aqueous solution.

When such a substance is used on a substrate having a basic property to deactivate an acid, a decomposition reaction of a t-butoxycarbonyl group is inhibited at the interface of the basic substrate. There is no change. Therefore, when there is a region where the acid is deactivated and a region where the acid is not deactivated on the substrate, the mixture can be selectively left only in the region where the acid is deactivated.

The flow will be described with reference to FIG. First, a basic pattern 62 made of a basic film is formed on a neutral base substrate 61 (FIG. 6A). This base substrate 61
A material to be modified by an acid reaction, for example, a chemically amplified positive resist 63 which becomes soluble in an alkaline solution by generating an acid upon exposure as described above is coated (FIG. 6B). Next, exposure is performed under predetermined conditions to generate an acid 64 in the film of the positive resist 63 (FIG. 6).
(C)).

Here, for the neutral base substrate 61,
Since the positive resist 63 is not modified, the dissolution reaction proceeds due to the generation of the acid 64. On the other hand, since the acid 64 is deactivated in the vicinity of the basic pattern 62, a region where a desired dissolution reaction does not proceed is generated (FIG. 6D). Therefore, even if the development with alkali is performed, the positive resist 63 remains as the insolubilized layer 65 only in the portion adjacent to the basic pattern 62 (FIG. 6E). In addition, the normal sputtering method or CV
Since an amorphous film is formed in the film formation by the method D,
In some cases, a film having a group active on an acid on the surface of the film and having basicity may be obtained.

Thus, on a basic substrate,
The acid generated in the resist due to the exposure is deactivated and the desired dissolution reaction cannot proceed. It is a well-known fact that a chemically amplified positive resist generates a resist residue on a specific film such as SiN _x , WSi, TiN, BPSG, Al, W (R. Yamanaka et Al: Jpn.J. Appl.Phys.Vo
l.34 (1995) 6794 and J. Sturtevant et Al: Proc. SPIE2197
(1995) 770. ). Conversely, well-cleaned Si, SiO ₂ film, thermal SiO _{2 ,} CVD-SiO ₂
In such cases, no tailing occurs.

FIG. 4B is a view of the manufacturing process after the exposure in FIG. In the horizontal direction, a substance 5 that does not deactivate the acid and a substance 6 that deactivates the acid are alternately arranged in a line, and the unexposed portion 41 and the exposed portion 4 are arranged in the vertical direction.
2 are alternately arranged in a line. The chemically amplified positive resist 21 is dissolved by exposure light.
In (b), it dissolves in the area of the exposed part 42.

In the substance 6 for deactivating the acid, the dissolution reaction of the chemically amplified positive resist 21 does not proceed, and an insolubilized layer 22 is formed. Therefore, the resist 21 is dissolved only in the overlapping region 43 of the exposed portion 42 and the substance 5 which does not deactivate the acid, and the chemically amplified positive resist 21 is removed only in the region 43 after the development. In addition, it can be seen that the width of the overlap region 43 is narrower than the space pattern width due to the insolubilized layer generated near the acid deactivating substance 6. Thus, the chemically amplified positive resist 2
1 is determined from the position of the base pattern in a self-aligning manner, which is advantageous for alignment exposure.

After the exposure step shown in FIG.
/ Bake treatment after exposure for 90 seconds (PEB: Post Exposur
e Bake), and the chemically amplified positive resist 21 is developed for 60 seconds with an aqueous solution of tetramethylammonium hydride (TMAH) of 0.21 normality. By this development, the resist 21 is removed in the linear light transmitting region, but the resist 21 remains in the unsolubilized layer 22 and the unexposed portion which is the light-shielding region, and the resist 21 is removed between the grooves formed between the insolubilized layers 22. A hole pattern is formed (FIG. 2F).

Based on the resist pattern formed by the steps up to the development, dry etching is performed so that the underlying substrate 1 is exposed by digging into the interlayer insulating film 4. In this dry etching, since the insolubilized layer 22 functions as a mask, the contact hole 31 having a width (0.1 μm) smaller than the pattern width (0.3 μm) of the substance 6 that deactivates the acid when the resist 21 is removed is formed. It is formed in a self-aligned manner (FIG. 3G). FIG. 4C shows a perspective view after the formation of the contact hole 31. Then, a conductive material 32 such as W is formed in the contact hole 31.
And the surface thereof is planarized by CMP or the like. As a result, a conductive layer 32 is electrically connected to a diffusion layer (not shown) formed on the base substrate 1.

As described above, a chemically amplified positive resist utilizing an acid catalyzed reaction for forming a pattern causes footing due to the deactivation of the acid on the substance which deactivates the acid. When a chemically amplified positive resist is applied, exposed, baked, and developed on the pattern made of the acid inactivating substance, a very small amount of resist remains in the acid inactivating substance due to the tailing effect. That is, when there is a pattern of a film that causes footing and a pattern of a film that does not cause footing on the substrate at the same time, the resist can be selectively adsorbed to the pattern that causes footing. If the tailing effect is combined with the patterning by ordinary exposure, a new pattern not in the exposure mask can be formed.

The position of the hole in the direction perpendicular to the line of the substance 6 for inactivating the acid is determined in a self-aligned manner from the position of the underlying pattern due to the footing effect of the chemically amplified positive resist 21. Such misalignment due to lack of accuracy of the overlay exposure does not occur. Furthermore, since a line-and-space pattern mask that can easily obtain a resolution is used as compared with a conventionally used hole pattern mask, it is advantageous in extending the life of photolithography.

In this embodiment, the interlayer insulating film 4
The case where BPSG is used as the
It is also possible to use an SG film, an SOG film, or the like. Also,
Substance 6 for deactivating acid by CMP method and conductive material 3
Although the case where the two surfaces are flattened has been described, it goes without saying that the present invention is also applicable to the case where the surface is flattened by, for example, etch back. Further, in the present embodiment, the case where the contact hole 31 is formed between the gate electrodes 3 and connected to the diffusion layer is shown. However, when forming the multilayer wiring, the contact hole when connecting the contact layer to the lower wiring is formed. The present invention can also be applied to the formation process of. Although the case where the contact layer is formed by the dual damascene process has been described, the gist of the present invention is not deviated without using the dual damascene process.

(Second Embodiment) FIGS. 7 to 9 are views for explaining a self-aligned pattern forming method according to a second embodiment of the present invention. This is an example in which a chemically amplified negative resist is used as a selective adsorbent instead of a positive resist. In the present embodiment, D
A case where a contact layer connecting a transistor and a wiring layer is formed in a RAM device or the like will be described. FIG. 10 shows a perspective view and a top view of the main steps in the pattern forming steps shown in FIGS.

First, a poly-Si / W
Gate electrode materials 3a and 3b made of Si or the like and an insulating film 3c made of SiN or the like covering the upper surfaces of the gate electrode materials 3a and 3b are deposited by a CVD method or the like. The thickness of each of the gate electrode materials 3a and 3b and the insulating film 3c is 100 n.
m, 55 nm, and 150 nm. Thereafter, the gate electrode materials 3a and 3b are formed using an anisotropic etching technique such as lithography and RIE (reactive ion etching).
Then, the insulating film 3c is etched until the underlying substrate 1 is exposed to form a plurality of linear gate electrodes 3 at intervals of 0.3 μm.

Then, a conductive material 71 made of W or the like is deposited on the base substrate 1 on which the plurality of gate electrodes 3 are formed so as to have a thickness of 200 nm from the base substrate 1. Then, on the conductive material 71, a substance 5 that does not deactivate an acid, such as SiO ₂ , is formed to a thickness of 100 nm by a CVD method or the like.
And annealed (FIG. 7A).
Next, on the material 5 which does not deactivate the acid, a material 6 which deactivates the acid made of SiN or the like by a CVD method or the like has a thickness of 1.
It is deposited to a thickness of 00 nm (FIG. 7B).

The acid-inactivating substance 6 has the same width and pitch as the gate electrode 3 of the line pattern formed thereunder, and the acid-inactivating substance 6 is located just above the gate electrode 3. In order to perform patterning, exposure is performed using a line pattern mask 51 shown in FIG. 5A using, for example, a lithography method and an anisotropic etching technique such as RIE. A line & space pattern is formed (FIG. 7C). FIG. 10A is a perspective view after the line & space pattern is formed.

Next, a chemically amplified negative resist 81 (SN) is formed on the line-formed acid deactivating substance 6.
R200 (Shipley) is applied (FIG. 8D).
The chemically amplified negative resist 81 is made of a resin in which crosslinking progresses between polymers due to an acid catalyzed reaction and causes a reduction in the dissolution rate in a specific solvent or an aqueous alkaline solution. After applying the resist, a pre-bake at 130 ° C. for 60 seconds is performed to a film thickness of about 300 nm. Then, exposure is performed by the KrF excimer stepper NSR S201A (Nikon Corporation) using the mask 52 shown in FIG. 5B in which a line pattern orthogonal to the mask 51 is arranged by the light shielding part 52a and the light transmitting part 52b.

At the time of this exposure, the molecular weight becomes infinite in the linear light transmitting region of the chemically amplified negative resist 81 due to a crosslinking reaction. At the time of this exposure, an acid is generated, so that the chemically amplified negative resist 81 is formed.
Promotes the crosslinking reaction of However, near the surface of the substance 6 for inactivating the acid formed under the chemically amplified negative resist 81, the acid is inactivated by the substance 6 for inactivating the acid, and the crosslinking reaction of the resist 81 is stagnated. On the other hand, on the surface of the substance 5 that does not deactivate the acid, there is no deactivation of the acid near the substance 6 that deactivates the acid, and a sufficient crosslinking reaction proceeds. Therefore, only in the vicinity of the surface of the substance 6 that deactivates the acid, the chemically amplified negative resist 81 selectively suspends the crosslinking reaction with the substance 6 that deactivates the acid, and only this portion remains as the solubilized layer 82 (FIG. 8 (e)).

FIG. 10B is a view of the manufacturing process after exposure in FIG. 8F as viewed from above. In the horizontal direction, the substance 5 that does not deactivate the acid and the substance 6 that deactivates the acid are alternately arranged in a line, and in the longitudinal direction, the unexposed portions 101 and the exposed portions 102 are alternately arranged in a line. I have. The chemically amplified negative resist 81 causes a cross-linking reaction by exposure light. In FIG. 10B, the cross-linking reaction is shown in the region of the exposed portion 102. In addition, the crosslinking reaction of the chemically amplified negative resist 81 does not proceed around the substance 6 that deactivates the acid,
Produces a solubilized layer. Therefore, the chemically amplified negative resist 8
No. 1 causes a crosslinking reaction only in the overlapping region 103 of the exposed portion 102 and the substance 5 which does not deactivate the acid, and remains in the overlapping region 103 after development. In addition, it can be seen that the width of the overlap region 103 is narrowed by the solubilized layer 82 generated near the acid deactivating substance 6.

After this exposure step, the P at 90 ° C./90 sec.
EB was performed. Next, development was performed for 60 seconds using a 0.14 N aqueous TMAH solution. By this development, the solubilized layer 8
2 and the unexposed portion 101, the chemically amplified negative resist 81 is removed, and a pillar pattern 83 made of the chemically amplified negative resist 81 is formed between the lines of the substance 6 for deactivating the acid (FIG. 8F). . And this pillar pattern 83
Is etched until the conductive material 71 is exposed, thereby forming a pillar pattern made of the substance 5 that does not deactivate the acid. (FIG. 9 (g)).

Further, using the chemically amplified negative resist 81 constituting the pillar pattern 83 and the substance 5 which does not deactivate the acid as a mask, the conductive material 71 is etched until the base substrate 1 is exposed. Then, the chemically amplified negative resist 81 used as the mask and the substance 5 that does not deactivate the acid are removed. Thus, only the pillar pattern 83 made of the conductive material 71 and the like and the plurality of gate electrodes 3 remain on the base substrate 1 (FIG. 9H). Then, an interlayer insulating film 91 is newly deposited on the underlying substrate 1 on which the pillar pattern 83 and the gate electrode 3 are formed, and the surface is etched by CMP so that the conductive material 71 is exposed to the interlayer insulating film 91. The contact layer is formed by flattening (FIG. 9 (i)).

As described above, according to the pattern forming method of this embodiment, the position of the pillar pattern in the direction orthogonal to the line pattern of the substance 6 for inactivating the acid is as follows.
Since the cross-linking reaction of the chemically amplified negative resist 81 is determined in a self-aligned manner from the position of the underlying pattern due to the selective stagnation of the cross-linking reaction, the overlay exposure with high precision is possible. In addition, since a pattern can be formed using a photomask having a line & space pattern, which is relatively easy to obtain a resolution, the life of optical lithography can be extended.

In the first and second embodiments, the amount of exposure of the chemically amplified resists 21 and 81, the material of the chemically amplified resists 21 and 81, the amount of heating, and the like are adjusted to adjust the base. The width of the contact hole and the pillar pattern with respect to the line pattern composed of the acid deactivating substance 6 can be easily changed. As described above, a new element isolation and a new wiring structure can be formed by using the fine pattern forming process using the present invention. Examples of the substance 6 for deactivating acid include SiN, TiN, Al, BPSG,
TEOS, poly-Si, or the like can be used. Examples of the substance 5 which does not deactivate the acid include thermal SiO ₂ , C
VD-SiO ₂ or the like can be used. Further, the line pattern composed of the gate electrode 3 and the second film formed immediately above the gate electrode 3 does not necessarily have to have the same width. That is, the width of the line pattern may differ depending on the width of the chemically amplified resists 21 and 81 remaining or dissolved to function as a mask.

In this embodiment, the case where the pillar pattern is formed between the gate electrodes and this pillar pattern is connected to the diffusion layer has been described. However, when forming the multilayer wiring, the lower wiring and the upper layer are formed through the contact layer. The present invention is also applicable to a process of forming a pillar pattern serving as a contact layer when connecting a wiring.

[0049]

As described above, according to the method of forming a self-aligned pattern according to the present invention, a chemically amplified resist is applied to a base pattern composed of a substance that deactivates an acid and a substance that does not deactivate the acid. By selectively applying a deactivating action to the light, and combining this with exposure that does not utilize a normal deactivating action, a new pattern can be formed in combination with a mask of a different design.

Further, since the resist pattern formed by the deactivating action of the substance which deactivates the acid is determined in a self-aligned manner from the position of the underlying pattern, misalignment due to the lack of precision of the overlay exposure as in the prior art does not occur. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing a forming step of a self-aligned pattern forming method according to a first embodiment of the present invention.

FIG. 2 is an exemplary sectional view showing a forming step of the method for forming a self-aligned pattern according to the embodiment;

FIG. 3 is an exemplary sectional view showing a forming step of the method for forming a self-aligned pattern according to the embodiment;

FIG. 4 is a perspective view and a top view of the semiconductor device during a pattern forming step in the same embodiment.

FIG. 5 is a view showing a mask pattern used for pattern formation in the embodiment.

FIG. 6 is a sectional view showing details of a reaction operation of the chemically amplified positive resist in the embodiment.

FIG. 7 is a sectional view showing a forming step of a self-aligned pattern forming method according to a second embodiment of the present invention.

FIG. 8 is a sectional view showing a forming step of the self-aligned pattern forming method according to the embodiment.

FIG. 9 is an exemplary sectional view showing a forming step of the method for forming a self-aligned pattern according to the embodiment;

FIG. 10 is a perspective view and a top view of the semiconductor device during a pattern forming step in the same embodiment.

FIG. 11 is a perspective view and a sectional view showing a pattern formed by a conventional pattern forming method and a case where a problem occurs.

FIG. 12 is a diagram showing a mask pattern used for conventional pattern formation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Undersubstrate 2 Gate oxide film 3 Gate electrode 3a, 3b Gate electrode material 3c Insulating film 4,91 Interlayer insulating film 5 Substance which does not deactivate acid 6 Substance which deactivates acid 21, 63 Chemical amplification type positive resist 22, 65 Insolubilized layer 31 Contact hole 32, 71 Conductive material 41, 101 Unexposed portion 42, 102 Exposed portion 43, 103 Overlap region 51, 52 Mask 51a, 52b Light shielding portion 51b, 52b Light transmissive portion 61 Neutral base substrate 62 Basic Pattern 64 Acid 81 Chemically amplified negative resist 82 Solubilized layer 83 Pillar pattern

Claims (2)

[Claims] A step of forming a second film made of a substance that deactivates an acid on a first film made of a substance that does not deactivate an acid, and a step of selectively removing the second film to form a second film. Forming a plurality of line patterns of the second film, applying a chemically amplified positive resist to the first film and the second film, and applying a chemically amplified positive resist to the first film and the second film. Exposing a line-shaped pattern intersecting with the line length direction of the second film to transform a resist in an exposed region excluding the periphery of the second film into a solubilized layer; A method of forming a self-aligned pattern, comprising: a step of developing a positive resist; and a step of etching the first film using a resist pattern formed by the development as a mask. 2. A step of forming a second film made of a substance that deactivates an acid on a first film made of a substance that does not deactivate an acid, and selectively removing the second film to form the second film. Removing the first film,
A step of forming a plurality of line patterns of the second film; a step of applying a chemically amplified negative resist to the first film and the second film; and a step of forming a line pattern on the first film and the second film. Exposing using a line-shaped pattern intersecting with the line length direction of the second film to transform a resist in an exposed region excluding the periphery of the second film into an insolubilized layer; A step of developing an amplified negative resist; and a step of etching the first film and the second film using the resist pattern formed by the development as a mask. Forming method.