Etching a substrate: processes – Forming or treating article containing magnetically...
Reexamination Certificate
2000-01-28
2002-12-10
Mills, Gregory (Department: 1763)
Etching a substrate: processes
Forming or treating article containing magnetically...
C216S067000, C216S075000, C029S607000
Reexamination Certificate
active
06491832
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of processing a specimen using a plasma etching process, an apparatus therefor, and a method of manufacture of a magnetic head using the same.
A specimen, such as a substrate of a semiconductor device and the like, is subjected to etching processing, for example, using a chemical solution or plasma. In such etching processing of the specimen, it is necessary to pay sufficient attention to the occurrence of corrosion in the specimen after the etching processing.
As such anti-corrosion technology for the specimen after the etching processing, there is a known technique as disclosed, for example, in JP-A Laid-Open No. 59-186326, wherein any chlorine compound, which is a corrosive substance remaining in resist films and the like is removed by ashing processing of the resist films using a plasma in a plasma process chamber which is in communication with an etching chamber that is maintained in a vacuum. Further it is known that, by heating the specimen after etching at 200° C. or more, evaporation of the chlorine compound, which is a corrosive substance remaining in the specimen, is promoted, thereby preventing the occurrence of corrosion of the specimen after etching. Further, there is also a known process, as disclosed in JP-A Laid-Open No. 61-133388, wherein an object to be treated, such as a specimen which has been etched, is transferred from the etching chamber to a heat treatment chamber in which the object to be treated is dried by blowing heated air over it, then it is taken out of the heat treatment chamber to be rinsed with water and then dried, thereby preventing the corrosion of the object after its etch processing due to reaction with the atmosphere.
JP-A Laid-Open No. 2-224233 discloses a method for processing specimens, which method is comprised of: a first step of etching a specimen, in the form of a lamination which contains different metals each having a different ionization characteristic from the other, using a first gas plasma via a resist mask formed on the lamination specimen in a first processing chamber; a second step of removing the resist mask and residual corrosion substances deposited on a side wall of the laminated specimen containing metals having different ionization characteristics from each other, which are formed in the first step, by processing the specimen in a second processing chamber using a second gas plasma formed in a different gas atmosphere from that of the first gas plasma; and a third step of removing a remaining portion of the residual corrosive substances deposited on the side wall of the laminated specimen which could not have been removed by the second step, by causing surfaces of the specimen which are exposed by the first and the second steps to come into contact with at least one liquid. According to this method, in the first step, the specimen which is prepared by laminating an Al alloy film and a TiW or TiN film is etched using a gas plasma which contains chlorine via the resist mask under decompression; in the second step, the specimen is subjected to an ashing process using a gas plasma which contains oxygen; and in the third step, the specimen is rinsed with water, and wherein in order to remove the residual corrosive substances remaining after the first step, the third step is comprised of at least one of the steps of: (a) rinsing in water; (b) further rinsing in water after rinsing in an alkaline liquid; (c) still further rinsing in water after rinsing in an acidic liquid, and (d) rinsing in water after rinsing in a fluoro-acid solution.
A method of etching a material used for magnetic poles in a thin film magnetic head, magnetic sensor and the like, which contains Fe, is disclosed in JP-A Laid-Open No. 4-107281. In this publication, a method of etching alloys which contain Fe, in particular, Fe—Si—Al alloy, formed on a surface of a specimen is disclosed, which method is comprised of: a step of etching a specimen which is heated in a vacuum at a temperature which is above 250° C. and below its melting point in an atmosphere of chlorine gas by a reactive ion milling method; a step of post-processing the specimen which is maintained at a high temperature above 250° C. by applying a chlorine ion shower thereto in order to allow for etching residuals remaining on the surface of the specimen to completely react with the chlorine gas; and a step of pure water processing for dissolving and removing etching products which are produced in the post processing step by submerging the specimen in pure water, wherein the above-mentioned steps are executed consecutively in the sequence described above.
Further, JP-A Laid-Open No. 7-93293 discloses a method which is comprised of the steps of: etching a specimen formed of a lamination of wired material which contains aluminum; then removing halogen compounds and resist compounds at the same time.
A problem associated with the technique indicated in JP-A Laid-open No. 4-107281 resides in the fact that, in a case where pure Fe which is 3 &mgr;m thick is etched by argon ion milling for the manufacture of a magnetic head, because the etching rate is approximately 150 A/min, it takes 200 min. This is because the etching rate is controlled by the number of incident ions. In order to improve the etching rate, it is suggested in JP-A Laid-open No. 4-107281 that by heating a specimen above 250° C., and by applying reactive ion milling in a chlorine gas atmosphere, the etching rate can be improved approximately to 1000 A/min. However, there is a problem in that some types of specimens cannot withstand a temperature above 250° C. depending on the materials, thereby preventing application of the above-mentioned method. In particular, there arises a problem when etching a laminated film which contains a ferromagnetic material of NiFe alloy for use in the manufacture of a magnetic head in that, if the temperature of its specimen rises above 230° C., the magnetic property of its NiFe film is deteriorated, and even when its temperature drops to the normal temperature, its original magnetic property cannot be recovered, thereby rendering it useless.
Still further, an anti-corrosion process is proposed for preventing corrosion which occurs in a specimen which is left after application of reactive ion milling in JP-A Laid-Open No. 4-107281, comprising: a post-treatment process for applying a chlorine ion shower onto the specimen which is heated at a temperature above 250° C.; and a pure water immersion process for immersing the specimen in pure water, wherein the above-mentioned processes are executed sequentially in this order. However, there is a problem in that the temperature of the specimen rises above 250° C., and a complicated sequence of anti-corrosion processing, including the ion shower and then the pure water immersion processes, is required, thereby increasing the cost of manufacture.
The above-mentioned complicated sequences for corrosion prevention processes are considered to be due to the fact that the specimen target, which is a Fe—Si—Al alloy and contains two different metals which differ greatly in ionization characteristics from each other, as indicated in JP-A Laid-open No. 2-224233, has a high corrosiveness.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of processing a specimen for corrosion prevention thereof, an apparatus therefor and a method of manufacture of a magnetic head using the same, which allows for etching of a specimen, such as a laminated film containing NiFe alloy, at a high rate and at a temperature which is low enough not to destroy the device, in a simple manner and at a low cost.
A method for accomplishing the object of the invention is comprised of the steps of: etching a specimen, for example, a magnetic pole for a magnetic head, which is formed using NiFe alloy, after plasma processing the same using a relatively high density plasma source; and subjecting the specimen to a post-plasma processing for corrosion prevention immediately after the etching, using a
Fuyama Moriaki
Harata Hitoshi
Kanai Saburou
Okada Tomohiro
Torii Yoshimi
Alejandro Luz
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Mills Gregory
LandOfFree
Method for processing specimens does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for processing specimens, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for processing specimens will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2948491