JP2000029230A - Method for removing resist material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the peelability of a used resist material on an article such as a semiconductor wafer and to surely remove the resist material independently of its processed state when the resist material is peeled and removed using an adhesive sheet. SOLUTION: An adhesive sheet is stuck on a resist material present on an article and this adhesive sheet and the resist material are peeled in one body to remove the resist material on the article. In this method, the article is subjected to such surface treatment as to reduce its surface free energy to <=60 dyn/cm before the resist material is disposed on the article.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for forming a fine pattern in the production of semiconductors, circuits, various printed boards, liquid crystal panels, etc., in which unnecessary resist materials on articles such as semiconductor wafers are removed. On how to do it.

[0002]

2. Description of the Related Art As LSI densities and integrations have increased, and liquid crystal panels have increased densities and screen sizes, it has become necessary to easily and reliably remove resist materials present on semiconductor wafers and glass substrates. It is very important to ensure product yield and reliability. Conventionally, in the process of removing the resist material, dry removal using an asher (ashing device)
Wet removal with a resist removal solvent is common.

[0003] However, in the removal by the ashes, it takes a long time to remove the resist material after the high dose ion implantation, and in the case of the plasma assing, the damage to the substrate due to the use of the plasma is problematic. Become. In addition, the removal of the wet by the solvent for removing the resist has problems such as deterioration of the working environment, global environmental problems such as waste liquid treatment, and the resist material once removed is reattached to the wafer.

In order to solve these problems, there has been proposed a method of removing a resist material by using an adhesive sheet such as a sheet or a tape. In this method, an adhesive sheet is attached to an article on which a resist material is present, the resist material is fixed to an adhesive layer, and then the adhesive sheet and the resist material are peeled off integrally. The material is removed from the article. According to this method, there is no problem as in the conventional method using an asher or a solvent, and as a result, the yield of the product is also improved.

[0005]

However, in the above-described removal method using an adhesive sheet, there is a case where the resist material cannot be completely peeled off from an article such as a semiconductor wafer depending on the treatment of the resist material. Atsuta. Especially 1 ×
It is often difficult to peel off a resist material that has been ion-implanted with a high dose of 10 ¹⁵ ions / cm ² or more.

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a method for removing unnecessary resist material on an article such as a semiconductor wafer by using an adhesive sheet to enhance the peelability of the resist material. It is another object of the present invention to provide a method for removing a resist material that can be reliably removed regardless of the processing state of the resist material.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, before providing a resist material on an article such as a semiconductor wafer, a specific surface treatment was performed on the article. When the surface free energy is set to a certain value or less, the releasability of the resist material provided thereon is enhanced, and the processing of the resist material is performed by sticking and peeling of the adhesive sheet. The present inventors have found that they can be reliably removed irrespective of the state, and that the reliability of peeling can be greatly improved, and the present invention has been completed.

That is, according to the present invention, an adhesive sheet is adhered to an upper surface of a resist material present on an article, and the adhesive sheet and the resist material are peeled off integrally to form a resist on the article. In the method of removing material, the surface free energy of the material is reduced by 60% before the resist material is provided on the material.
The present invention relates to a method for removing a resist material, wherein a surface treatment for making dyne / cm or less is performed. In addition, the present invention, by the surface treatment on the article,
According to a second aspect of the present invention, there is provided a method for removing a resist material having a contact angle of water of 40 ° or more on an article surface.

In the present specification, the surface free energy of an article is defined as the contact angle of the article surface measured with water and methylene iodide. Energy value (known from literature)
Is substituted into the following equation 1 derived from the Young's equation and the extended Fowkes equation, and the resulting two equations are solved as simultaneous linear equations, thereby obtaining the surface free energy value of the solid. . <Equation 1> (1 + cos θ) γ _l = 2 {(γ _S ^d γ _l ^d ) +2}
(Γ _S ^P γ _l ^P) wherein each symbol in the formula is as follows. theta: contact angle gamma _l: surface free energy of the contact angle measurement liquid - γ _l ^d: γ dispersion force component in _l gamma _l ^P: polar force component in γ _l γ _S ^d: surface free energy of the solid (product) - in Dispersion force component γ _S ^P : Polar force component in surface free energy of solid (article)

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, when a resist material is provided on an article such as a semiconductor wafer, the surface of the article on which the resist material is provided is subjected to a surface treatment in advance, and the surface free energy is reduced to 60 dyne / cm or less. , Preferably 50
It is characterized in that it is set in a range of up to 30 dyne / cm. In addition, it is desirable that the surface treatment be such that the contact angle of water on the surface of the article is 40 ° or more, particularly 55 to 80 °. When such a surface treatment is performed, the adhesiveness of the resist material provided thereon is appropriately weakened,
Good results are obtained in the releasability of the adhesive sheet in a later step.

The above-mentioned surface treatment may be performed by any method such as a chemical method, a physical method or a combination thereof. As an example, there is a hydrophobic treatment method in which an article such as a semiconductor wafer is exposed to a vapor of an organosilicon compound such as hexamethyldisilazane and then heated, and in this method, by adjusting the above-described exposure time and the like, The surface free energy of the article and the contact angle of water on the article surface are set within the above range. If the surface free energy and the like cannot be set within the above range due to insufficient adjustment, good results cannot be obtained in the peelability of the resist material.

After the surface treatment of the article as described above, a known resist material is applied thereon, and a predetermined resist pattern (resist film image) is formed by an ordinary photo process, and the resist material is used as a mask. For example, the openings are subjected to various processes such as ion implantation of As ⁺ , P ⁺ , and B ⁺ , and other processes such as etching, and finally, unnecessary resist material (resist film image) is removed to form a circuit. I do.

Here, the resist material is removed by a method in which an adhesive sheet is adhered to the upper surface and the adhesive sheet and the resist material are integrally peeled off. The above-mentioned adhesive sheets have a thickness of polyester, polycarbonate, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and the like. Usually 10
A 1,000 μm film is used as a base material, and a pressure-sensitive adhesive layer having a thickness of usually 20 μm or more is provided on the film base material to form a sheet or tape.

The pressure-sensitive adhesive layer may be of a non-curable type, but is preferably of a curable type in order to cleanly remove the resist material. The curable pressure-sensitive adhesive layer is cured (solidified) by cooling from a heated state such as a hot-melt pressure-sensitive adhesive
For example, a pressure-sensitive adhesive such as an acrylic polymer or a polymerization-curable pressure-sensitive adhesive obtained by adding a curable compound and a polymerization catalyst to an adhesive polymer such as an acrylic polymer is used. Among these, it is particularly desirable to use a polymerization-curable pressure-sensitive adhesive, particularly an ultraviolet-curable pressure-sensitive adhesive.

By the above-mentioned peeling operation, the resist material is removed from the article together with the adhesive sheets. At that time, since the surface free energy of the article is set in the above range and the adhesion between the article and the resist material is appropriately weakened, for example, the resist material may be ionized regardless of the processing state of the resist material. Even if a hard surface layer or the like is formed due to deterioration due to injection or the like, there is no concern that the resist material remains on the article, and the resist material can be reliably removed by the above-described peeling operation.

The present invention is not limited to the example of semiconductor device manufacturing, and is not limited to any application as long as it is an article having a pattern made of a resist material, and can be applied to various articles. Needless to say,

[0017]

Next, an embodiment of the present invention will be described in more detail. Hereinafter, “parts” means “parts by weight”.

Example 1 A CVD (Chemical Vapor Depth) was formed on the surface.
A silicon wafer on which an oxide film having a thickness of 10 nm is formed by an oxidation method is exposed to vapor of hexamethyldisilazane at 80 ° C. for 5 minutes and then dried in dry air.
Heat treatment was performed at 0 ° C. for 90 seconds. The surface free energy of this silicon wafer is 40.6 dyne / cm and the contact angle of water is 6
It was 5.0 °. The thickness of 1μ on this silicon wafer
After applying a negative resist material, heating, exposing, and developing a resist film image, using this as a mask, ion implantation energy of 80 keV and ion implantation concentration of 1 are used.
P ⁺ ions were implanted at × 10 ¹⁶ ions / cm ² .

An ultraviolet-curable pressure-sensitive adhesive sheet was bonded on the silicon wafer thus prepared by pressing it on a heating plate at 130 ° C. After that, ultraviolet rays were irradiated by a high-pressure mercury lamp at an irradiation amount of 900 mJ / cm ² , and after curing treatment, the adhesive sheet was peeled off to obtain an adhesive sheet.
And the resist material (resist film image) were integrally peeled and removed. When the surface of the silicon wafer was observed under a microscope,
It was confirmed that the resist material on the wafer was completely removed.

The above-mentioned UV-curable adhesive sheet is
It was produced by the following method. First, acrylic acid n
-A monomer mixture consisting of 80 parts of butyl, 15 parts of ethyl acrylate and 5 parts of acrylic acid, 150 parts of ethyl acetate,
Using 0.1 part of azobisisobutyronitrile, solution polymerization was performed at 60 ° C. for 12 hours under a nitrogen stream to obtain an acrylic polymer solution having a weight average molecular weight of 500,000.

In this solution, based on 100 parts of the acrylic polymer, 50 parts of polyethylene glycol diacrylate as a curable compound, urethane acrylate [trade name "UN" manufactured by Shin-Nakamura Chemical Co., Ltd. -01 "] 50 parts, a polyisocyanate compound as a polyfunctional compound [trade name" Coronate L "manufactured by Nippon Polyurethane Industry Co., Ltd.] 3
Parts, and 3 parts of [dimethoxy (phenyl)] methylphenylketone as a photopolymerization initiator were uniformly mixed to prepare an ultraviolet-curable pressure-sensitive adhesive solution.

Next, the pressure-sensitive adhesive solution was applied to a thickness of 50 μm.
m was coated on a base material made of a polyester film having a thickness of 35 μm after drying, and dried at 130 ° C. for 3 minutes to produce an ultraviolet-curable pressure-sensitive adhesive sheet. 18 with respect to the silicon wafer of this adhesive sheet before ultraviolet curing.
The 0 ° peel adhesive strength was 10 g / 10 mm width, and the peel adhesive strength after ultraviolet curing was 13 g / 10 mm width.

Example 2 A silicon wafer having an oxide film having a thickness of 10 nm formed on its surface by a CVD method was exposed to steam of hexamethyldisilazane at 80 ° C. for 2 minutes, and then dried at 180 ° C. in dry air.
For 90 seconds. The surface free energy of this silicon wafer is 44.3 dyne / cm, and the contact angle of water is 60.
It was 1 ゜. After a resist film image was formed on this silicon wafer in the same manner as in Example 1, ions were implanted under the same conditions as in Example 1 using this as a mask.

On the silicon wafer thus produced, an ultraviolet-curable pressure-sensitive adhesive sheet was attached in the same manner as in Example 1, and the same curing treatment as in Example 1 was performed.
The adhesive sheet was peeled off, and the adhesive sheet and the resist material (resist film image) were integrally peeled and removed. Microscopic observation of the surface of the silicon wafer confirmed that the resist material on the wafer was completely removed.

COMPARATIVE EXAMPLE 1 A silicon wafer having an oxide film having a thickness of 10 nm formed on its surface by a CVD method was exposed to steam of hexamethyldisilazane at 80 ° C. for 10 seconds, and then dried in dry air for 180 seconds.
C. for 90 seconds. The surface free energy of this silicon wafer is 61.8 dyne / cm, and the contact angle of water is 3
It was 6.1６. Example 1 on this silicon wafer
After a resist film image was formed in the same manner as in the above, ion implantation was performed under the same conditions as in Example 1 using this as a mask.

On the silicon wafer thus produced, an ultraviolet-curable adhesive sheet was attached in the same manner as in Example 1, and the same curing treatment as in Example 1 was performed.
The adhesive sheet was peeled off, and the adhesive sheet and the resist material (resist film image) were integrally peeled and removed. As a result of microscopic observation of the surface of the silicon wafer, most of the resist material on the wafer was removed, but a slight resist residue (about 30 μm square) was recognized, which was not sufficiently satisfactory.

[0027]

As described above, according to the present invention, in a method of peeling and removing a resist material on an article using an adhesive sheet, the resist material is provided on an article such as a semiconductor wafer. By applying a specific surface treatment to the article and setting the surface free energy to a certain value or less, the releasability of the resist material provided thereon is enhanced, and the treatment is not related to the processing state of the resist material. Thus, it is possible to provide an industrially useful method for removing a resist material which can be reliably removed by stripping.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takuji Okeyi 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 2H096 AA25 AA26 AA27 CA01 LA06 LA16 5F046 MA19

Claims (2)

[Claims] Claims: 1. An upper surface of a resist material present on an article,
In a method of attaching an adhesive sheet and peeling the adhesive sheet and the resist material together to remove the resist material on the article, before providing the resist material on the article, A method for removing a resist material, wherein a surface treatment is performed to reduce the surface free energy to 60 dyne / cm or less. 2. The method for removing a resist material according to claim 1, wherein the surface treatment on the article makes the contact angle of water on the article surface 40 ° or more.