Semiconductor device manufacturing: process – Chemical etching – Combined with the removal of material by nonchemical means
Reexamination Certificate
2002-05-17
2003-10-28
Thompson, Craig (Department: 2813)
Semiconductor device manufacturing: process
Chemical etching
Combined with the removal of material by nonchemical means
Reexamination Certificate
active
06638864
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for removing an unnecessary resist material on an article such as a semiconductor wafer in a step of forming a fine pattern involved in a process of manufacturing semiconductors, circuits, various printed boards or liquid crystal panels. The process of the invention is described hereinafter by reference to an example of manufacturing semiconductors. However, the invention is not limited only to the use, and may be applied to an article having a resist material on its surface and, in particular, it is preferably employed for removing a thick resist material on a wafer which becomes unnecessary after plating.
2. Description of the Related Art
In manufacturing semiconductor devices, a step of coating (applying) a resist material on a wafer such as silicon, forming a resist pattern image through a common photographic procedure, plating or etching using the resist as a mask, and removing the unnecessary resist material is repeatedly conducted. In the case of forming a circuit on various substrates (boards), unnecessary resist materials are removed.
With an increase in degree of pattern density or integration of LSI and an increase in degree of pattern density or size of liquid crystal panels, it is of importance to simply and surely remove unnecessary materials existing on semiconductor wafers or glass substrates in view of yield and reliability of products. As the step for removing unnecessary resist materials, there have conventionally been commonly employed a wet removing method using a resist-removing chemical solution and a dry removing method using an asher (a carbonizing apparatus) but, with resist materials having a large thickness, the removing method using a chemical solution has mainly been employed in view of throughput.
However, the removing method using a chemical solution requires to use a large quantity of harmful chemicals, and involves a fear for detrimental influences on the working environment and a problem that measures for protecting environment is burdensome. In addition, there is a fear of adverse affects on product properties or yield such as damages of a device surface with the chemical solution or re-adhesion of the resist having once been removed with the chemical solution.
In order to solve these problems, there has been proposed a simple method of removing a resist material using a pressure-sensitive adhesive sheet in a form of sheet or tape (hereinafter, sometimes referred to merely as a pressure-sensitive adhesive sheet). This method comprises adhering a pressure-sensitive adhesive sheet onto an article having provided thereon a resist material to firmly fix the resist material to the pressure-sensitive adhesive layer, and releasing both the pressure-sensitive adhesive sheet and the resist material in an integrated state (i.e., releasing the pressure-sensitive adhesive sheet and the resist material at the same time) to thereby remove the resist material from the article. This method does not involve the problems with other conventional methods and thus serves to improve yield of products.
With the above-described removing method using a pressure-sensitive adhesive sheet, however, there have often been cases where the resist material cannot completely be removed from the surface of an article such as a semiconductor substrate, with part of the resist material remaining on the article. Particularly in releasing the resist material from a wafer after plating the wafer in a step of, for example, forming a bump on the wafer, there have frequently been involved a problem that the resist material remains on the side of the bump or on the surface of the wafer substrate due to internal failure (also called cohesive failure) of the resist material.
SUMMARY OF THE INVENTION
Therefore, an object of the invention is to improve the method of releasing a resist material using a pressure-sensitive adhesive to thereby surely remove such resist material as described above from an article.
As a result of intensive investigations to attain the above-described object, the inventors have found that, in releasing a pressure-sensitive adhesive sheet adhered onto an article such as a semiconductor substrate, the resist can simply and surely be removed from the article with preventing internal failure of the resist material and thus leaving no resist material on the article, by using a material having strong dynamic properties against deformation as the resist material, thus having completed the invention.
That is, the invention provides (1) a method for removing a resist material by adhering a pressure-sensitive adhesive sheet onto the surface of a resist material existing on an article and releasing both the pressure-sensitive adhesive sheet and the resist material in an integrated state to thereby remove the resist material on the article, in which method the resist material has a Young's modulus of 0.5 MPa or more upon releasing; (2) a method for removing a resist material by adhering a pressure-sensitive adhesive sheet onto the surface of a resist material existing on an article and releasing both the pressure-sensitive adhesive sheet and the resist material in an integrated state to thereby remove the resist material on the article, in which method the resist material has a tensile strength at break of 0.5 MPa or more upon releasing; (3) a method for removing a resist material by adhering a pressure-sensitive adhesive sheet onto the surface of a resist material existing on an article and releasing both the pressure-sensitive adhesive sheet and the resist material in an integrated state to thereby remove the resist material on the article, in which method the resist material has a tensile elongation at break of 30% or more upon releasing; (4) the method for removing a resist material as described in one of (1) to (3), wherein the resist material has rubber elasticity; (5) the method for removing a resist material as described in one of (1) to (3), wherein the resist material contains a rubbery component; (6) the method for removing a resist material as described in one of (1) to (3), wherein the resist material contains a urethane component; and (7) the method for removing a resist material as described in one of (1) to (3), wherein the resist material contains a cyclized rubber and/or a bisazide compound.
DETAILED DESCRIPTION OF THE INVENTION
In the invention, an article on which a resist material exists includes, for example, an article such as a semiconductor substrate or a glass substrate which is in a state wherein a known resist material is coated on the article, a predetermined resist pattern (resist film image) is formed through a common photographic process, and various treatments such as metal plating or etching is conducted at the openings of the resist. Here, the resist material commonly has a thickness of about 1 &mgr;m to about 150 &mgr;m, though not being particularly limited thereto.
In the invention, a pressure-sensitive adhesive sheet is adhered onto the upper surface of the resist material existing on the article. As the pressure-sensitive adhesive sheet, known pressure-sensitive adhesive sheets for releasing a resist material are used, with those which have good adhesion properties to a resist material being preferably used.
The resist material to be used in the invention has such tough dynamic properties against deformation that it can be peeled off with leaving no residues on the article without causing internal failure such as break or tearing upon releasing operation through the pressure-sensitive adhesive sheet. As a resist material composition capable of exhibiting such properties, there may be considered various combinations and, for example, it is effective for imparting rubber elasticity to the resist material. The rubber elasticity herein means elasticity that rubber or rubber-like material shows generally. Such a material has a property where it is difficult to break against deformation due to stress. As resist materials useful for the purp
Ioka Haruo
Toyoda Eiji
Nitto Denko Corporation
Thompson Craig
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