JP2002141259A - Manufacturing method for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method where a satisfactory resist pattern is formed on a wafer, and the resist pattern is removed easily without damaging the wafer. SOLUTION: The manufacturing method consists of a process (i), where a water-soluble organic layer is formed on the film to be worked or on a substrate and a resist layer for silylation is formed on it; a process (ii) wherein a prescribed pattern is exposed to the resist layer for silylation, an exposed part is subjected to silylation, so as to be dry-developed by using an oxygen plasma and the resist layer in the prescribed pattern is formed; and a process (iii) wherein a desired treatment is executed by using the resist layer into a desired pattern as a mask and a process (iv) where the organic layer is removed by using an aqueous solution and the resist layer is lifted off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming and removing a resist pattern when manufacturing a semiconductor element or an integrated circuit.

[0002]

2. Description of the Related Art As the degree of integration of semiconductor devices increases, the miniaturization of patterns is also accelerating. To date, lithography technology, which promotes miniaturization, has been improved in process aspects such as shortening the wavelength of light used for resist exposure, annular illumination, super-resolution technology such as phase shift mask, and electron beam drawing. Therefore, resist materials suitable for them have been developed.

[0003] Optical lithography has an optical problem that a sufficient depth of focus (DOF) cannot be obtained when resolving a fine pattern. When a resist pattern is formed on a substrate having a step or a portion having a different reflectance, the pattern size and the resist shape are affected by the light reflected from the substrate. As the integration becomes higher, the pattern becomes finer and the level difference of the substrate becomes larger. Therefore, it becomes difficult to form a fine pattern with high accuracy.

In addition, KrF or A from g-line and i-line
As the wavelength of the light source for the rF excimer laser becomes shorter, the light absorption into the resist material becomes larger, so that it is difficult to cause a photoreaction to the lower part of the resist layer, and a good resist shape cannot be obtained. Electron beam lithography is expected to have high resolution without being affected by light absorption and interference as described above, but due to the effects of backscattered electrons from the substrate and scattered electrons inside the resist film, the resolution is high. Have a limit, and the proximity effect also becomes a problem.

As means for solving these problems, there are a multilayer resist process and a silylation process. These are both dry development processes using oxygen plasma, instead of using an alkaline developer as in the prior art.

[0006] The former process has complicated steps, and the optimum material for the upper layer resist cannot be determined. Therefore, there are many problems in practical use. On the other hand, in the latter, the process is simple, and in recent years, a silylation process using an ArF excimer laser as an exposure light source has been frequently developed.

FIG. 2 shows a process chart of a conventional silylation process using a negative mold. In this process, after a silylation resist 12 is applied onto a substrate or a film 11 to be processed (FIG. 2A), only a part 12a of the resist surface is exposed to light, an electron beam, or the like (FIG. 2B). )). Next, a material containing an element having high etching resistance to oxygen plasma such as silicon is applied in a liquid phase or a gas phase, and a resist silylation layer 14 is selectively formed on the resist upper layer (FIG. 2C). )), Using this as a mask to perform dry development with oxygen plasma to form a resist pattern (FIG. 2)
(D)) The process.

In this process, it is only necessary to expose the resist surface, so that a high resolution can be realized. In addition, since there is no influence from the reflection from the underlying substrate, a vertical and high aspect ratio can be obtained even on a substrate with a high step. The resist shape can be formed.

[0009]

In the above-described method, the silylation process is regarded as promising as a future miniaturization technique. However, the problem with the above process is that
Difficulty in stripping the resist pattern.

After the resist pattern is etched or ion-implanted into a wafer using the resist pattern as a mask,
Although the resist pattern is ultimately removed, the resist pattern that has been subjected to the silylation process has etching resistance to oxygen plasma, so that it is not possible to use a commonly used resist removal method using oxygen plasma.

In addition, since the resist pattern is highly crosslinked by baking or the like, and is deteriorated by etching or ion implantation on the wafer, it is often difficult to remove the resist pattern with a solution (FIG. 2E). )).

[0012] It is possible to easily remove the resist by improving the dry etching time and bias conditions of the oxygen plasma and improving the peeling property, but the damage to the wafer itself such as gate destruction due to a charge-up phenomenon is possible. Could give.

As a method of forming a resist pattern in which a water-soluble organic substance is coated under the same resist, see Japanese Patent Application Laid-Open No.
JP-A-335516 [Method of Manufacturing Semiconductor Device] and JP-A-6-326018 [Resist Structure and Pattern Forming Method for Pattern Format] are described, both of which relate to a multilayer resist process. In the case of the above publication, MIBK (methyl isobutyl ketone) and IPA (isopropyl alcohol) are used as a developer for the upper resist.
Since a developer consisting of a mixture of the above is used, when developing the upper resist, a water-soluble organic substance thereunder is dissolved at the same time, so that a problem that the upper resist flies off occurs.

The present invention has been made in view of such circumstances, and a resist pattern formed by using a silylation process by forming a water-soluble organic material layer under a silylation resist layer in advance. And a method capable of easily removing the wafer without damaging the wafer.

[0015]

According to the present invention, there is provided: i) a step of forming a water-soluble organic material layer and a silylation resist layer thereon on a film to be processed or a substrate; Exposing a predetermined pattern, silylating the exposed portion, and subjecting the exposed portion to dry development using oxygen plasma to form a predetermined pattern resist layer, iii) performing a desired process using the predetermined pattern resist layer as a mask, iv) It is intended to provide a method of manufacturing a semiconductor device, comprising a step of lifting off a resist layer by removing an organic layer using an aqueous liquid.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Since the present invention aims at easily removing resist in a silylation process, a water-soluble organic material layer is formed on a substrate or a film to be processed by spin coating, and then the silyl is removed. It is preferred that the resist layer is formed by spin coating. The thickness of the water-soluble organic material layer is preferably about 400 to 700 °, and the thickness of the silylation resist layer is preferably 1 to 3 μm. At this time, since the water-soluble organic substance and the silylation resist can be continuously processed by the same spin coater, the number of steps is not increased as compared with the existing process.

After that, exposure, a silylating agent such as HMD
After heating in an S atmosphere to silylate the exposed portion, dry development using oxygen plasma is performed. At this time, since the water-soluble organic material layer has no etching resistance to oxygen plasma, it is removed together with the resist layer to form a resist pattern.

Thereafter, a desired process is performed using the resist layer having a predetermined pattern as a mask. The desired process is, for example, a process such as ion implantation or etching for a film to be processed or a substrate. Next, when removing the resist pattern, an aqueous liquid is poured onto the wafer with a spin coater because a water-soluble organic layer exists below the resist pattern. Or the water-soluble organic material layer is easily removed just by putting the wafer in the tank containing the aqueous liquid,
At this time, the resist pattern is also removed by lift-off.

In the present invention, since the resist pattern can be easily removed with the aqueous liquid, the wafer itself does not suffer damage such as charging. In addition, since the substrate or the film to be processed is not in contact with the resist pattern, there is no possibility of peeling remaining. The resist material used to form the resist layer for silylation is not particularly limited as long as the resist material is composed of a phenolic resin and a photosensitizer, and the portion irradiated with light can be silylated by a silylating agent. The silylation resist may be a positive type or a negative type.

As a material used for forming the water-soluble organic material layer, for example, a commercially available antireflection film material containing polyvinyl alcohol as a main component, methyl cellulose, or the like can be used. The aqueous liquid used to remove the organic layer is
It may be water, a mixed solution of water and a water-soluble solvent, or an aqueous developer. Examples of the aqueous developer include TMAH. Further, it may be removed by an aqueous liquid discharged from a spin coater. The step of forming a resist layer having a predetermined pattern can be performed in a tank for containing an aqueous liquid to be used for removing a water-soluble organic substance layer later.

[0021]

[Embodiment 1] The present invention will be described in detail below with reference to embodiments. FIG. 1 is a process chart showing a method for manufacturing a semiconductor device of the present invention. First, a water-soluble organic material mainly containing polyvinyl alcohol is applied on a substrate or a film to be processed (hereinafter, referred to as a wafer) 1 by a spin coater to form a water-soluble organic material layer 3. Thereafter, prebaking is performed under the conditions of 90 ° C./30 sec.

As the organic substance, a commercially available material for an antireflection film is used, and the film thickness is about 400 to 700 °. The material of this antireflection film is generally TARC (Top An
ti Reflective Coating) is a material applied in a process called resist coating, which is applied to the surface of the resist film to suppress multiple reflections in the resist film, thereby reducing the standing wave effect and reducing the line width. Variation can be suppressed.
In addition, since this material is water-soluble and is removed during development, there is an advantage that the number of steps is not increased.

Next, a resist material for negative silylation is applied with a thickness of about 1 μm to 3 μm using the same spin coater to form a resist layer 2 (FIG. 2A). The resist material uses diazonaphthoquinone as a photosensitive agent and a novolak resin as a base resin. At this time, the water-soluble organic material layer 3 and the silylation resist layer 2
Is formed by a continuous process using a spin coater. Thereafter, a part 2a of the resist layer 2 is exposed to KrF excimer laser using a predetermined chromium mask (FIG. 2B).

Next, by heating in an HMDS (hexamethyldisilazane) atmosphere at a temperature of 150 to 200 ° C. for 3 to 4 minutes, the exposed area 2a is silylated to form a resist silylated layer 4 (FIG. 2 (e)). )).

Thereafter, the unreacted portions of the resist layer 2 for silylation and the water-soluble organic material layer 3 are removed by dry etching using O ₂ as an etching gas to obtain a vertical, high aspect ratio, for example, an aspect ratio of 10 to 20. Is formed (FIG. 2D). Then, after the wafer 1 is dry-etched using this resist pattern as a mask, the wafer 1 is subjected to 1500 to 1500 spin coating.
While rotating at about 3000 rpm for about 1 minute, pure water is dropped, and the resist pattern is removed by washing with water (FIG. 2 (e)).

At this time, in order to prevent the removed resist pattern from re-adhering to the wafer 1 to form particles (particles), after washing with water, the wafer 1 is rotated with an organic solvent such as thinner using the same cup. The resist adhered to the wafer 1 is removed while the resist adhered to the side wall of the cup is also dissolved. Thus, generation of particles can be prevented.

Example 2 A resist pattern was formed in the same manner as in Example 1, and the wafer 1 was dry-etched using this resist pattern as a mask (FIG. 2).
(D)) Using a wet cleaning device, the wafer 1 is placed in a first tank containing pure water at room temperature for about one minute, and the resist pattern is removed by a dipping method. Thereafter, the wafer 1 is placed in a second tank containing the next organic solvent or sulfuric acid, and the re-adhered resist is dissolved. Next, the wafer 1 is placed in a third tank containing pure water and the wafer 1 is completely washed. At this time, the first tank in which the resist is floating is subjected to liquid exchange for each treatment, and the tank can be washed to reduce particles. Also, if a filter is put in the waste water pipe to completely remove the resist in the pure water, the liquid can be reused.

[0028]

According to the present invention, since a water-soluble organic material layer is formed before forming a silylation resist layer, a good resist pattern can be formed on a film to be processed or a substrate. The removed resist pattern can be easily removed without damaging the film to be processed or the substrate.

[Brief description of the drawings]

FIG. 1 is a process chart showing a method of forming and removing a resist pattern in a silylation process of the present invention.

FIG. 2 is a process diagram showing a method of forming and removing a resist pattern in a silylation process according to a conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 substrate or processed film 2 silylation resist 3 water-soluble organic substance 4 resist silylation layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/42 H01L 21/308 E H01L 21/3065 21/30 574 21/308 568 569H 572B 21/302 H F term (reference) 2H025 AA00 AB16 AC08 AD01 AD03 DA33 DA40 FA03 FA12 FA20 FA39 FA48 2H096 AA00 AA25 BA01 BA09 CA05 EA05 FA04 FA05 GA37 GA38 HA11 HA30 JA03 JA04 LA02 LA03 5F004 DA26 DB23 DB26 EA04 EA10 CC05 CC02 CC02 DD15 DD18 EE07 EE08 5F046 LB01 MA01 MA07 PA07

Claims (8)

[Claims] 1. A step of: i) forming a water-soluble organic material layer and a silylation resist layer thereon on a film to be processed or a substrate; ii) exposing a predetermined pattern to the silylation resist layer;
A step of silylating the exposed portion and subjecting it to dry development using oxygen plasma to form a resist pattern of a predetermined pattern, iii) a step of performing a desired treatment using the resist layer of the predetermined pattern as a mask, iv) using an aqueous liquid Removing the organic material layer to lift off the resist layer. 2. The method according to claim 1, wherein the aqueous liquid is water, a mixture of water and a water-soluble organic solvent, or an aqueous developer. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the water-soluble organic material layer is removed by an aqueous liquid discharged from a spin coater. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the water-soluble organic material layer is formed of an antireflection film material containing polyvinyl alcohol as a main component. 5. The method for manufacturing a semiconductor device according to claim 1, wherein the step of forming the water-soluble organic material layer and the resist layer for silylation is performed by continuous processing using a spin coater. 6. The method of manufacturing a semiconductor device according to claim 1, wherein the desired treatment is an ion implantation or an etching treatment. 7. The method for manufacturing a semiconductor device according to claim 1, wherein the silylation resist layer is a positive type or a negative type. 8. The method according to claim 1, wherein the step of forming a resist pattern having a predetermined pattern is performed in a tank for containing an aqueous liquid used for removing the water-soluble organic substance layer later. 3. The method for manufacturing a semiconductor device according to item 1.