Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
2000-03-28
2002-10-15
Ashton, Rosemary (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S271100, C430S311000, C430S313000, C430S324000
Reexamination Certificate
active
06465149
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a solution to be optically treated, a method for forming an antireflection film, a method for pattern-plating and a method for manufacturing a thin film magnetic head using the pattern-plating method.
2. Related Art Statement
In a manufacturing method of a thin film magnetic head, normally, a second magnetic film serving as a top magnetic film is formed after a first magnetic film (bottom magnetic film), a gap film, an insulating film to support a coil film are formed on a wafer. Moreover, in the case of forming the second magnetic film, a plate-underfilm is formed on the whole surface of the wafer including the insulating film by a sputtering method, etc. Subsequently, a photoresist is applied on the surface of the plate-underfilm and is processed by a photolithography method to form a resist frame for forming the second magnetic film. Then, the second magnetic film is formed in the area surrounding the resist frame by an electroplating, etc. A film composed of the material constituting the second magnetic film is plated in an area beyond the resist frame, but it is removed.
In the second magnetic film-forming process, however, an exposing light in the photolithography process to form the resist frame is reflected at the surface of the insulating film and then, the reflected exposing light reaches an area beyond a photomask-defining area and exposes the photoresist around the area, resulting in the degradations of the pattern precision of the resist frame and the second magnetic precision.
The degradation of the pattern precision is conspicuous at the pole portion of the second magnetic film. The pole portion of the second magnetic film is opposed to the first magnetic film via the gap film. On the backward area from the pole portion is positioned the insulating film rising up with an inclination of a given angle from the surface of the gap film. The starting point of the rising up corresponds to a Throat Height zero point and the rising up angle corresponds to an Apex Angle.
The second magnetic film constitutes the pole portion parallel to the gap film and the first magnetic film up to the Throat Height zero point and then, rises up with an inclination of the Apex Angle toward the top surface of the insulating film from the Throat Height zero point.
Thus, in the case of fabricating the resist frame for forming the second magnetic film by the photolithography process, the photoresist stuck on the inclined portion at the Apex Angle of the insulating film toward the top surface must be exposed.
The plate-underfilm already stuck on the inclined portion reflects the exposing light. The part of the reflected exposing light reaches the pole portion. Thus, the exposing pattern of the pole portion is different from that of the photomask, resulting in the pattern destruction in a part of the resist frame corresponding to the pole portion.
The pattern destruction of the resist frame has difficulty in developing a recording density by narrowing a recording track width up to not more than 1.0 &mgr;m.
Japanese Patent Application Kokai Hei 9-180127 (JP A 9-180127) discloses that before applying the photoresist as a mask for a top magnetic film, is formed the antireflection film, on which the photoresist frame is applied and the photoresist is exposed and developed to form the resistframe.
However, the conventional antireflection film is not dissolved in an alkaline developer to remove the resist frame. Accordingly, the antireflection is removed by an ashing method, etc. after the resist frame is removed by the alkaline developer, and then, the second magnetic film is formed, which results in the increase of the process number.
The antireflection film exists over the interior pattern surrounded by the resist frame. Then, the interior pattern has a pole portion area corresponding to the pole portion of the top magnetic film and a second yoke portion area corresponding to a yoke portion. Thus, the antireflection film has to be removed in both the pole portion area and the yoke portion area.
In the resist frame, however, the pole portion area has an extremely different opening area from that of the second yoke portion. Moreover, the pole portion tends to have the narrowed opening area of not more than 1 &mgr;m for a high density recording. Accordingly, in the case of removing the antireflection film stuck on the interior pattern surrounded by the resist frame, the pole portion area has an extremely different etching rate from that of the second yoke portion, so that the pole portion area requires a longer etching time than the yoke portion area. As a result, the resist frame in the pole portion area is etched largely during the removing the antireflection film, resulting in the large distance of the resist frame. In other words, the antireflection film to narrow the width of the pole portion enlarges the distance of the resist frame because of the removing process of the film, resulting in having difficulty in narrowing the pole portion.
For explaining the conventional problems concretely, the method for the thin film magnetic head was described as above-mentioned, but the above problem is generally brought about in a pattern-plating method to plate a pattern on a surface of a body to be plated including an inclined portion.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a solution to be optically treated to form an antireflection film which resolves a photoresist developer without the intermixing with the photoresist and a method for producing the antireflection film using the solution.
It is another object of the present invention to provide a method for pattern-plating using the solution to be optically treated and a method for manufacturing a thin film magnetic head using the pattern-plating method.
It is still another object of the present invention to provide a method for manufacturing a thin film magnetic head in which a magnetic film is formed in a high precise pattern on an insulating film.
It is further object of the present invention to provide a method suitable for manufacturing a thin film magnetic head having a narrowed recording track width.
This invention relates to a solution to be optically treated comprising a cyclopentanone solvent, polymethylglutarimide and a light absorption dye.
In forming the antireflection film using the solution to be optically treated, the solution is applied onto an object body and thermally treated. Thereby, the antireflection film capable of dissolving in the alkaline developer which-is used in the photoresist developing can be obtained without the intermixing with the photoresist. The thermal treatment is preferably carried out at a temperature of 100-200° C.
In the case of pattern-plating using the solution to be optically treated, the antireflection film is formed on a surface of a body to be plated including an inclined portion. Next, the photoresist is formed so as to cover the antireflection film.
Subsequently, a photolithography process to form a plated pattern on the body is carried out for the photoresist and the antireflection film to form a resist frame composed of the photoresist and the antireflection film.
Since the antireflection film capable of dissolving into the alkaline developer which is used on the photoresist developing is formed without the intermixing with the photoresist, in the case of forming the resist frame through the photolithography process, the photoresist and the antireflection film can be patterned at the same time so as to have their same pattern. Moreover, since in the photolithography process, another process to remove the antireflection film is not required, the photolithography process can be simplified.
The solution to be optically treated and the pattern-plating method exhibit conspicuous operation/working effects. As is well known, the thin film magnetic head has a slider and a thin film magnetic head element. The slider has an air bearing surface in the opposing side to a recording medium. The t
Hokushin Jun-ichi
Kamijima Akifumi
Ashton Rosemary
TDK Corporation
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