JP2000124097A - Method for forming pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for forming a pattern to avoid collapsing of the pattern of a resist. SOLUTION: This method for forming a pattern comprises steps of coating a resist 9 on a semiconductor substrate 8, transferring the pattern to a resist 9 via a mask 10, developing the semiconductor substrate 8 with a developer liq. 12 to form a pattern of a resist 9a, substituting a rinsing liq. 13 for the developer liq. 12 which remain on the semiconductor substrate 8, and drying and removing the rinse liq. 13 remaining on the semiconductor substrate 8. In this case the drying and removing of the liq. is done, so that the forming face of the resist 9a formed on the semiconductor substrate 8 is in downward in direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method for preventing a resist pattern from collapsing in a method of manufacturing a semiconductor device.

[0002]

2. Description of the Related Art With the demand for higher integration of semiconductor devices, development of microfabrication techniques has been promoted. Among these fine processing techniques, an exposure method using ultraviolet rays, X-rays, electron beams, or the like has been proposed in order to realize formation of a fine pattern. And by using these exposure methods,
The aim is to form a 0.2-0.1 μm line and space pattern.

FIG. 2 is a sectional view showing a conventional resist pattern forming method. The pattern forming method will be described based on the drawings. First, a resist 2 is formed on a semiconductor substrate 1.
Is applied. Next, a mask 3 is disposed above the resist 2 and the resist 2 is exposed by exposure light 4 (FIG. 2).
(A)). As the exposure light 4, ultraviolet rays, X-rays, or electron beams as described above are used.

Next, the semiconductor substrate 1 is developed with a developing solution 5 to obtain a patterned resist 2a (FIG. 2).
(B)). Next, the developing solution 5 on the semiconductor substrate 1 is replaced with a rinsing solution 6 and removed (FIG. 2C). As the rinsing liquid 6, pure water or the like is used. Next, the semiconductor substrate 1
The upper rinsing liquid 6 is dried while the semiconductor substrate 1 is rotated and shaken off (FIG. 2D) to form a resist 2a having a pattern formed on the semiconductor substrate 1 (FIG. 2).
(E)).

Since the pattern of the resist 2a is fine and has a high aspect ratio, the surface tension of the rinsing liquid 6 acts between the resists 2a when the rinsing liquid 6 is dried. As shown in FIG.
There is a problem that the resists 2a are pulled together and cannot withstand this force, causing the resist 2a to fall down and failing to obtain a desired pattern. As a conventional method for solving this problem, for example, “Handbook of Resist Materials for Semiconductor Integrated Circuits” (Realize, published in 1997)
Pages 217 to 220.

As one method, for example, a method has been proposed in which the rinsing liquid 6 has a low surface tension and uses an 11% aqueous solution of tertiary amyl alcohol. However, although the surface tension of the rinsing liquid 6 is reduced to prevent the resist 2a from falling down, there is a problem that the resist 2a is easily peeled.

As another method, a method has been proposed in which the rinsing liquid 6 is frozen and sublimated (the surface tension becomes almost zero). However, the process becomes complicated, and problems such as compatibility with the resist 2a after freeze-drying and volume change during freezing occur.

As another method, a photo-crosslinkable resist is used as the resist 2, and after removing the developing solution 5 with a rinsing solution 6 as shown in FIG.
The resist 2a in the rinsing liquid 6 is subjected to collective light irradiation 7 and cured to form a resist 2b (FIG. 3A). next,
The rinsing liquid 6 on the semiconductor substrate 1 is dried while the semiconductor substrate 1 is rotated and shaken off (FIG. 3 (b)) to form a resist 2b patterned on the semiconductor substrate 1 (FIG. 3 (c)). ).

When the rinsing liquid 6 is dried, the surface tension of the rinsing liquid 6 acts between the resists 2b as in the above-described conventional case, but since the resist 2b is hardened, the surface of the rinsing liquid 6 is hardened. The resist 2a does not fall down due to the tension as shown in FIG. However, this method requires a waste liquid treatment by using a new organic solvent, and the introduction of a new exposure apparatus and the like in the process of FIG. 3A, which causes a problem that the production cost increases. .

[0010]

The conventional pattern forming method is performed as described above. When the rinsing liquid 6 is dried, the cohesive force (expressed by surface tension) of the rinsing liquid 6 acts between the resists 2a, and the resist is formed. In the case of the pattern collapse of 2a or the method for solving it, there is a problem that various problems occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the cohesive force of a rinsing liquid is reduced.
It is an object of the present invention to provide a pattern forming method capable of preventing pattern collapse and minimizing inconvenience caused thereby.

[0012]

Means for Solving the Problems Claim 1 according to the present invention.
The pattern forming method is to apply a resist on a semiconductor substrate, transfer the pattern to the resist through a mask, develop the semiconductor substrate with a developer to form a pattern made of the resist, and remain on the semiconductor substrate. In a pattern forming method for removing a developing solution by replacing it with a rinsing solution and drying and removing a rinsing solution remaining on the semiconductor substrate, the drying and removing of the rinsing solution may be performed in such a manner that a surface of a resist formed on the semiconductor substrate faces downward It is installed and performed so that

According to a second aspect of the present invention, in the pattern forming method, pure water is used as the rinsing liquid.

According to a third aspect of the present invention, there is provided a pattern forming method according to the first or second aspect, wherein the drying and removing of the rinsing liquid is performed while rotating with the direction of the center axis of the semiconductor substrate being vertical. is there.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described. FIG. 1 is a sectional view showing a method for forming a resist pattern according to Embodiment 1 of the present invention. The pattern forming method will be described based on the drawings. First,
As in the conventional case, a resist 9 is applied on the semiconductor substrate 8. Next, a mask 10 is disposed above the resist 9 and the resist 9 is exposed by exposure light 11 (FIG. 1).
(A)). As the exposure light 11, ultraviolet rays, X-rays, or electron beams can be used.

Next, the semiconductor substrate 8 is heated and the resist 9
Promotes the reaction of Next, the semiconductor substrate 8 is coated with the developing solution 12.
Then, a resist 9a patterned and obtained is obtained (FIG. 1B). Next, the developing solution 12 on the semiconductor substrate 8 is replaced with a rinsing solution 13 and removed (FIG. 1C). As the rinsing liquid 13, pure water or the like is used. next,
The semiconductor substrate 8 is turned upside down so that the surface on which the resist 9a is formed on the semiconductor substrate 8 faces downward.

Then, the semiconductor substrate 8 is rotated to rinse off the rinsing liquid 13 on the semiconductor substrate 8 (FIG. 1).
(D)) By drying and removing, a resist 9a patterned on the semiconductor substrate 8 is formed (FIG. 1 (e)). The rotation at this time is such that the center axis of the semiconductor substrate 8 is vertical. If the drying and removing step is performed while heating to, for example, about 80 ° C. to 120 ° C., the drying and removing can be performed in a short time.

When the rinsing liquid 13 is dried and removed, the surface on which the resist 9a is formed on the semiconductor substrate 8 faces down. And the cohesive force of the rinsing liquid 13 is smaller than in the conventional case. Therefore, the resist 9a
Even if the cohesive force of the rinsing liquid 13 acts during this process, the resist 9a can be formed without causing the conventional resist 9a to collapse.

In the present invention, the semiconductor substrate 8
The surface on which the resist 9a is formed is turned upside down, that is, lower than the conventional case, so that it is not necessary to use a different material from the conventional case, and the number of steps is increased accordingly. There is no need to perform this operation, and no other problems occur due to this.

In the pattern forming method of the first embodiment configured as described above, the rinsing liquid 13 is dried and removed with the resist 9a formed on the semiconductor substrate 8 facing downward. In addition, the cohesive force of the rinsing liquid 13 acting on the resist 9a becomes smaller than that of the conventional case due to the reaction of gravity, thereby preventing the resist 9a from falling down.

The following experiment was conducted in order to compare the difference between the present invention and the conventional phenomenon. This will be described with reference to FIG. First, a chemically amplified negative resist 9 (here, “TDUR-N908” manufactured by Tokyo Ohka Kogyo Co., Ltd. is used) is applied on the semiconductor substrate 1 by a spin coating method.
Heating was performed at 110 ° C. for 90 seconds on a hot plate to obtain a resist 9 having a thickness of 0.8 μm. next,
Using an X-ray exposure apparatus, X-rays of 155 mJ / cm ² were irradiated (FIG. 1A). Next, on a hot plate,
Heating was performed at 30 ° C. for 90 seconds to accelerate the reaction of the resist 9.

Next, development is performed for 60 seconds with a developing solution 12 (here, "NMD-3" manufactured by Tokyo Ohka Kogyo Co., Ltd.) (FIG. 1B), and a rinsing solution 13 (here, pure water is used). use)
Then, the developer 12 is replaced and removed (FIG. 1C). Next, the semiconductor substrate 8 is turned upside down, the semiconductor substrate 8 is rotated, and the rinse liquid 13 is shaken off (FIG. 1D) and dried and removed to form a patterned resist 9a (FIG. 1E). )).

When the resist 9a thus formed was observed with a scanning electron microscope, the minimum value was 0.14 μm.
It was confirmed that the resist 9a was formed up to the line-and-space pattern without the pattern collapse. After developing by the same method and replacing the developing solution 12 with the rinsing liquid 13 and removing the same, the semiconductor substrate is not turned upside down as in the conventional method. When the resist pattern was formed while it was set to be on the upper side, it was similarly observed with a scanning electron microscope. As a result, it was confirmed that a line and space pattern smaller than 0.16 μm had collapsed. .

As is clear from this, when the semiconductor substrate 8 is turned upside down and the surface on which the resist 9a is formed on the semiconductor substrate 8 faces downward, the rinsing liquid 13 is dried and removed. It can be confirmed that even a line and space smaller than the conventional case can be formed without pattern collapse.

Although an example in which pure water is used as the rinsing liquid 13 has been described, it goes without saying that the same tendency can be obtained with other solutions, and it is needless to say that the pattern collapse of the resist can be prevented as compared with the conventional case. No.

[0026]

As described above, according to the first aspect of the present invention, a resist is applied on a semiconductor substrate, a pattern is transferred to the resist through a mask, and the semiconductor substrate is developed with a developer. In a pattern forming method of forming a pattern made of a resist, replacing and removing a developing solution remaining on the semiconductor substrate with a rinsing liquid, and drying and removing the rinsing liquid remaining on the semiconductor substrate, the rinsing liquid is dried and removed. Since the resist is formed on the semiconductor substrate so that the surface on which the resist is formed faces downward, the cohesive force applied to the resist when the rinse liquid is removed by drying is reduced, and the resist pattern can be prevented from collapsing. It is possible to provide a pattern forming method.

According to a second aspect of the present invention, there is provided a pattern forming method according to the first aspect, wherein pure water is used as the rinsing liquid, so that problems caused by the rinsing liquid can be minimized. It becomes possible.

According to a third aspect of the present invention, there is provided a pattern forming method according to the first or second aspect, wherein the drying and removing of the rinsing liquid is performed while rotating with the direction of the center axis of the semiconductor substrate being vertical. It is possible to provide a pattern forming method capable of promptly removing and drying a rinse liquid.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing a conventional pattern forming method.

FIG. 3 is a cross-sectional view showing another conventional pattern forming method.

[Explanation of symbols]

8 semiconductor substrate, 9, 9a resist, 10 mask,
11 exposure light, 12 developer, 13 rinse.

Continuation of the front page (72) Inventor Atsushi Oshida 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 2H096 AA25 GA18 GA20 5F046 LA03 LA14

Claims (3)

[Claims] 1. A step of applying a resist on a semiconductor substrate, a step of transferring a pattern to the resist through a mask, and a step of developing the semiconductor substrate with a developer to form a pattern made of the resist And a step of removing the developing solution remaining on the semiconductor substrate by replacing it with a rinsing solution, and a step of drying and removing the rinsing solution remaining on the semiconductor substrate, wherein the pattern forming method comprises: A pattern forming method, wherein the rinsing liquid is removed by drying so that a surface on which the resist is formed on the semiconductor substrate faces downward. 2. The pattern forming method according to claim 1, wherein pure water is used as the rinsing liquid. 3. The pattern forming method according to claim 1, wherein the rinsing liquid is dried and removed while rotating the semiconductor substrate so that the direction of the center axis is vertical.