Semiconductor device manufacturing: process – Forming schottky junction – Compound semiconductor
Reexamination Certificate
2003-04-09
2004-08-24
Thompson, Craig A. (Department: 2813)
Semiconductor device manufacturing: process
Forming schottky junction
Compound semiconductor
C438S003000
Reexamination Certificate
active
06780738
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pattern forming method for forming a plurality of patterns made of respective metal materials different from each other on the same surface of a substrate, and a method of making a microdevice using the same. In the present invention, the microdevice encompasses thin-film magnetic heads, thin-film inductors, semiconductor devices, thin-film sensors, thin-film actuators, and apparatus incorporating them.
2. Related Background Art
Known as a method of forming a metal pattern on a substrate is so-called frame plating such as one disclosed in Japanese Examined Patent Publication No. SHO 56-36706, for example. This method comprises the steps of laminating an electrode film on a substrate, forming on the electrode film a resist frame exposing a desirable part of the electrode film therethrough, plating on the electrode film exposed through the resist frame a desirable metal layer while using the electrode film as an electrode, and forming a metal pattern on the substrate by removing the resist frame and the surplus of electrode film.
SUMMARY OF THE INVENTION
There are cases where such a frame plating method forms a plurality of patterns made of respective metal materials different from each other on the same surface of a substrate. Known as methods in such a case are one repeating for each metal material a series of steps of forming a resist frame, plating with a metal material, and removing the resist frame with respect to one kind of electrode film; and one repeating for each metal material a series of steps of forming an electrode film, forming a resist frame, plating with a metal material, and removing the resist frame and the surplus of electrode film.
When plating is repeated for each metal material with respect to one kind of electrode film as in the former, however, the combination of the electrode film and metal material is not always optimal, so that the state of film is hard to become favorable, whereby a metal pattern with a high adhesion may not be formed.
Though the combination of the electrode film and metal material can be optimized when all the steps from forming an electrode film to removing the same are repeated for each metal material as in the latter, an electrode film for the next metal material is laminated on the formed metal pattern, and thus must be completely removed in a later step. As a consequence, there have been cases where an electrode film material attaches to a side wall or the like of the formed metal pattern in particular, thereby becoming hard to remove, thus causing inconveniences.
In view of the problems mentioned above, it is an object of the present invention to provide a pattern forming method which can form a plurality of patterns made of respective metal materials different from each other with a high adhesion while restraining impurities from attaching thereto, a method of making a microdevice, a method of making a thin-film magnetic head, a method of making a magnetic head slider, a method of making a magnetic head apparatus, and a method of making a magnetic recording and reproducing apparatus.
The present invention provides a pattern forming method for forming a plurality of metal patterns made of respective metal materials different from each other on the same surface of a substrate, the method comprising an electrode film laminating step of laminating a plurality of electrode films corresponding to the respective metal materials on the substrate; a first pattern forming step of forming a first resist frame on a first electrode film located farthest from the substrate in the plurality of electrode films so as to expose a predetermined part of the first electrode film therethrough, plating the exposed part of the first electrode film with a metal material corresponding to the first electrode film so as to form a first metal pattern, and removing the first resist frame; a first electrode film removing step of etching the first electrode film away while using the first metal pattern as a mask so as to expose a second electrode film closer to the substrate than is the first electrode film; and a second pattern forming step of forming a second resist frame on the second electrode film so as to expose a predetermined part of the second electrode film therethrough, and plating the exposed part of the second electrode film with a metal material corresponding to the second electrode film so as to form a second metal pattern.
In the pattern forming method in accordance with the present invention, all the electrode films corresponding to respective metal materials forming desirable metal patterns are laminated on a substrate beforehand. Then, after the first metal pattern is formed by plating the first electrode film with a metal material suitable for the first electrode film, the first electrode film is etched away, so as to expose the second electrode film at the surface. Therefore, the second electrode film suitable for the metal material of the second metal pattern can selectively be plated, whereby the combination of each metal material and each electrode film can be optimized. Hence, the film quality of the plated metal pattern improves, so that the adhesion between the plated metal pattern and the electrode film can be enhanced.
Also, since all the electrode films are laminated on the substrate before forming metal patterns by plating, it is unnecessary for an electrode film for the next metal pattern to be formed on the substrate after one metal pattern is formed. Therefore, the electrode film for the next metal pattern does not attach to a metal pattern which has already been formed, whereby favorable metal patterns to which impurities attach less can be obtained.
Here, it is preferred that each of the metal materials and its corresponding electrode film be made of the same material.
When an electrode film and a material to be plated on the electrode film are made of the same material as such, metal ions and the like constituting the electrode film are prevented from dissolving from the electrode film into a plating solution of a plating bath and contaminating the plating solution and so forth during plating, whereby the metal pattern formed by plating is restrained from lowering its purity while adhesion is further improved between the metal material and electrode film.
The present invention provides a method of making a microdevice formed with a plurality of metal patterns made of respective metal materials different from each other on the same surface of a substrate, the method comprising an electrode film laminating step of laminating a plurality of electrode films corresponding to the respective metal materials on the substrate; a first pattern forming step of forming a first resist frame on a first electrode film located farthest from the substrate in the plurality of electrode films so as to expose a predetermined part of the first electrode film therethrough, plating the exposed part of the first electrode film with a metal material corresponding to the first electrode film so as to form a first metal pattern, and removing the first resist frame; a first electrode film removing step of etching the first electrode film away while using the first metal pattern as a mask so as to expose a second electrode film closer to the substrate than is the first electrode film; and a second pattern forming step of forming a second resist frame on the second electrode film so as to expose a predetermined part of the second electrode film therethrough, and plating the exposed part of the second electrode film with a metal material corresponding to the second electrode film so as to form a second metal pattern.
In the method of making a microdevice in accordance with the present invention, all the electrode films corresponding to respective metal materials forming desirable metal patterns are laminated on a substrate beforehand. Then, after the first metal pattern is formed by plating the first electrode film with a metal material suitable for the first el
Oliff & Berridg,e PLC
TDK Corporation
Thompson Craig A.
LandOfFree
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