Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With microwave gas energizing means
Reexamination Certificate
2001-04-13
2003-05-20
Osele, Mark A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With microwave gas energizing means
C156S247000, C156S281000
Reexamination Certificate
active
06565704
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the removal of an unnecessary resist material from an object such as semiconductor wafer at a step of forming a fine pattern during the preparation of semiconductors, circuits, printed circuit boards, liquid crystal panels, etc.
BACKGROUND OF THE INVENTION
In the process for the preparation of a semiconductor device, for example, a resist material is applied to a wafer such as silicon. The resist material is then subjected to ordinary photographic process to form an image made of resist pattern. With this image as a mask, the wafer is then etched. Unnecessary resist material is then removed. This procedure is then repeated. Unnecessary resist material is removed also in the case where a circuit is formed on various circuit boards.
With the recent tendency towards the enhancement of the density and integration of LSI and the density and size of liquid crystal panel, it has been important more and more from the standpoint of yield and reliability of product to simply and certainly remove unnecessary resist material from semiconductor wafer or glass substrate. Heretofore, a dry removal process using an asher (carbonization apparatus) or a wet removal process using a resist removing solvent has been normally employed at the step of removing unnecessary resist material.
However, the removal process using an asher is disadvantageous in that it takes much time to remove a resist material which has been doped with ions at a high dose. If plasma ashing is effected, the semiconductor substrate can be damaged by plasma. The wet removal process using a resist removing solvent is disadvantageous in that it deteriorates the working atmosphere and discharges waste liquid that pollutes the global atmosphere. This wet removal process is also disadvantageous in that the resist material which has once been removed could be again attached to the wafer.
In order to solve these problems, a process for the removal of a resist material has been proposed involving the use of a sheet-like or tape-like pressure-sensitive adhesive sheet. This removal process comprises applying a pressure-sensitive adhesive sheet to an object having a resist material provided thereon so that the resist material is fixed to the pressure-sensitive adhesive layer, and then peeling the pressure-sensitive adhesive sheet off the object together with the resist material to remove the resist material from the object. This removal process is free from the problems inherent to the conventional removal processes using an asher or solvent, contributing to the enhancement of the yield of product.
However, the foregoing removal process using a pressure-sensitive adhesive sheet is disadvantageous in that, in cases where some kinds of resist material are used or some kinds of treatment on resist material are effected, the resist material can not be removed completely from an object such as semiconductor substrate. In particular, resist materials doped with ions at a dose as high as not less than 1×10
15
ions/cm
2
can be hardly peeled off the substrate in most cases.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a process for the peeling of a resist material with a pressure-sensitive adhesive sheet which involves the improvement in the removal of resist material or the enhancement of peelability of resist material to certainly remove the resist material from the object regardless of the properties or treated state of the resist material.
The inventors made extensive studies of the foregoing object of the present invention. As a result, it was found as a first aspect that, by cooling the pressure-sensitive adhesive sheet together with the resist material and the object or heating them and then cooling, prior to peeling of a pressure-sensitive adhesive sheet applied to the upper surface of a resist material on an object such as semiconductor substrate, the shrinkage or expansion of the pressure-sensitive adhesive sheet is caused to impart a stress to the interface between the resist material and the object, thereby enhancing the peelability of the resist material and hence making it possible to simply and certainly remove the resist material from the object regardless of the properties of the resist material or other factors.
Furthermore, it was found as a second aspect that, prior to the application of the resist material to the object, by effecting a specific surface treatment to the object such that the surface of the object has a surface free energy of not greater than a predetermined value, the peelability of the resist material provided thereon can be enhanced, making it possible to certainly remove the resist material off the object with a pressure-sensitive adhesive sheet regardless of the treated state of the resist material and drastically enhance the reliability in peeling.
DETAILED DESCRIPTION OF THE INVENTION
The first aspect of the present invention especially concerns the following embodiments:
(1) A process for the removal of a resist material which comprises applying a pressure-sensitive adhesive sheet to the upper surface of a resist material present on an object, and then peeling the pressure-sensitive adhesive sheet together with the resist material to remove the resist material from the object, and after the application of the pressure-sensitive adhesive sheet, effecting a stress-imparting treatment which causes shrinkage or expansion of the pressure-sensitive adhesive sheet so that a stress develops at the interface between the resist material and the object,
(2) A process for the removal of a resist material of item (1), wherein the pressure-sensitive adhesive sheet comprises a curing type pressure-sensitive adhesive layer, and after the application of the pressure-sensitive adhesive sheet, a curing treatment for the curing type pressure-sensitive adhesive layer is effected and then the stress-imparting treatment is effected,
(3) A process for the removal of a resist material of item (1) or (2), wherein the stress-imparting treatment comprises (1) cooling the pressure-sensitive adhesive sheet, together with the resist material and object, to a temperature of not higher than 0° C. or (2) heating them to a temperature of not lower than 100° C. and then allowing the pressure-sensitive adhesive sheet to cool to room temperature, and
(4) A process for the removal of a resist material, wherein the pressure-sensitive adhesive sheet comprises an ultraviolet-curing pressure-sensitive adhesive layer, and, after the application of the pressure-sensitive adhesive sheet, irradiation of ultraviolet rays to the pressure-sensitive adhesive layer being in a thermally plasticized form is effected to cure the pressure-sensitive adhesive layer, and then spontaneous or forced cooling to room temperature is effected, whereby the curing treatment and stress-imparting treatment are effected simultaneously.
The term “object having a resist material provided thereon” as used herein is meant to indicate, e.g., one obtained by a process which comprises applying a known resist material to an object such as semiconductor substrate and glass substrate, subjecting the substrate to ordinary photographic process to form a predetermined resist pattern (resist film image) thereon, injecting ions such as As
+
, P
+
and B
+
into the substrate at the open side thereof with the resist material as a mask, and then subjecting the substrate to any other suitable treatments such as etching. The thickness of the resist material, if used as a mask with which ions are injected into the substrate, is normally in a range of from about 1 to 5 &mgr;m, but is not specifically limited.
In the first aspect of the present invention, a pressure-sensitive adhesive sheet is applied to the upper surface of the resist material present on the object. The application of the pressure-sensitive adhesive sheet may be effected at ordinary temperature. However, the pressure-sensitive adhesive sheet is preferably thermally contact-bonded to the resis
Namikawa Makoto
Okeyui Takuji
Toyoda Eiji
Nitto Denko Corporation
Osele Mark A.
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