JPH02121897A - Manufacture of membrane magnetic transducer - Google Patents

Abstract

PURPOSE:To shorten processing time by applying groove processing to a substrate along the membrane pattern thereof before polishing the rear of the substrate. CONSTITUTION:Grooves 13 are formed to a substrate wafer 12 composed of a magnetic body having a large number of membrane patterns 11 formed thereto along the membrane patterns 11, for example, by grindstone processing or laser processing so as to leave a definite thickness (t) in the substrate wafer 12. The substrate wafer 12 is bonded to a flat plate 14 by wax on the side of the patterns 11 and the rear of the substrate wafer 12 is subjected to plane polishing or lapping to remove the wafer 12 up to the thickness (t) or more and the substrate wafer 12 is divided at every thinned membrane patterns 11. Thereafter, the substrate wafers 12 are detached and washed to obtain the chips 15 of thinned membrane magnetic transducers. By this method, since the cut depth of cutting processing becomes shallow, processing time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention 1 (Field of Industrial Application) The present invention relates to a method of manufacturing a thin film magnetic transducer used in a thin portable memory card such as an IC card.

(Prior Art) In an IC card, the contents of the IC memory can be read by a conventional magnetic stripe card reader.
Cards with thin film magnetic transducers embedded within the card are being developed.

This was done in consideration of the lifespan of electrical contacts and the use of magnetic stripe card readers, which are currently in widespread use.Similar to IC chips, thin film patterns are formed in an array on a wafer-shaped substrate. After that, the manufacturing method is to cut it by machining and divide it into chips.

In the case of a magnetic transducer, a magnetic substrate wafer is generally used, but for various reasons, the back surface of the substrate is ground to reduce its thickness before being mounted in a card.

A method for manufacturing a thin film magnetic transducer will be explained using FIGS. 5 to 7.

First, a magnetic substrate wafer 2 made of ferrite or the like on which a large number of thin film patterns 1 as shown in FIG. The diagonally shaded portion of the back surface of the magnetic substrate wafer 2 is removed by surface grinding, lapping, etc. to make the magnetic substrate wafer 2 thin. After removing the magnetic substrate wafer 2 from the flat plate 3, as shown in FIG. 7, it is cut into pieces using a dicing machine or the like in accordance with the arrangement of each thin film pattern 1 to obtain chips 4.

By the way, as shown in FIG. 6, the back surface of the magnetic substrate wafer 2 is ground to reduce its thickness before being divided into chips in order to be mounted in an IC card with a thickness of 0.8 m. However, if the magnetic substrate wafer 2 is thinned from the beginning, the urchin/' itself will warp, which will cause problems in later steps. This is because, although it is usually necessary to polish the thin film forming side of the substrate by boring or the like in order to reduce its surface roughness, if one side is processed, the residual stress causes the substrate to warp. Furthermore, when a thin film is formed, the stress of the film causes the substrate to warp.

If the substrate is warped in this way, a gap will be created between the mask and the substrate during resist patterning, resulting in a difference in exposure amount, making it difficult to achieve highly accurate patterning. Further, since a passivation film such as 5to2, which is formed as an insulating film or a protective layer on a substrate, is brittle, there are problems such as cracks occurring due to warpage of the substrate.

Therefore, the above manufacturing method is adopted in consideration of the above-mentioned problems.

However, in the conventional manufacturing method for thin film magnetic transducers described above, after grinding the back side of the substrate, when removing wax for stickiness, and when removing cutting water and cutting powder after cutting into chips, Two cleaning steps are required, which increases the number of steps and makes it difficult to reduce costs. Therefore, it is possible to grind the back side of the board after dividing the chips, but in this case, it is difficult to attach multiple chips at the same time on a flat plate with high precision, and processing them one by one increases the number of man-hours. Therefore, it is disadvantageous.

Therefore, in addition to the above-mentioned manufacturing methods, it has been proposed to use a magnetic metal material such as permalloy instead of an oxide magnetic material such as ferrite for the substrate wafer, and to cut the substrate wafer using a laser as a chip division cutting method. .

However, when cutting with a laser in this way,
The cutting time is long, and as shown in FIG.
This affects the thickness of the divided chip, which causes a problem when mounting it on a card.

Accordingly, as shown in FIG.
After that, the deteriorated layer 7 is removed by chemical etching.
It may be possible to cut the material in a short time by melting it, but even in this case there is a problem that new steps will be required.

(Problems to be Solved by the Invention) As mentioned above, in the conventional manufacturing method of thin-film magnetic transducers, the number of steps involved in chip cutting increases, which increases the processing time and makes it difficult to reduce costs. There are challenges that are difficult.

The present invention is intended to solve the above-mentioned conventional problems,
Processing time when cutting chips can be shortened,
It is an object of the present invention to provide a method for manufacturing a thin film magnetic transducer that can reduce costs.

[Structure of the Invention] (Means for Solving the Problems) The present invention involves forming grooves at a predetermined depth from the surface of the substrate so as to divide each of the thin film patterns into a substrate on which a large number of thin film patterns are formed. After that, the substrate is divided into each of the thin film patterns by grinding the back surface of the substrate.

(Function) In the present invention, after cutting grooves along the thin film pattern of the substrate, the back surface of the substrate is ground to divide the substrate into each thin film pattern, thereby reducing the processing time during chip cutting. be able to.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 are diagrams for explaining a method of manufacturing a thin film magnetic transducer according to an embodiment of the present invention.

First, as shown in the figure, a large number of thin film patterns 11
Grooves 13 are formed in the magnetic substrate wafer 12 on which the wafer 12 is formed along each thin film pattern 11 so as to separate each thin film pattern 11 by, for example, grindstone processing or laser processing. This groove 13 is formed leaving a constant thickness t of the substrate wafer 12, as shown in FIG.

Then, as shown in FIG. 3, the substrate wafer 12 is pasted on the flat plate 14 with the thin film pattern 11 side of the substrate U/X 12 using wax or the like.
By removing the back surface of the substrate 2 by surface grinding, lapping, etc. to a thickness t or more shown in FIG.
As the thickness of \12 is reduced, the thin film pattern 11
The substrate wafer 12 is divided into two parts.

Thereafter, the substrate wafer 12 is removed from the flat plate 14 and washed, thereby obtaining a thin-film magnetic transducer chip 15 shown in FIG. 4.

Therefore, in the thin film magnetic transducer of this embodiment, after grooves are formed on the substrate wafer, the next step of back grinding of the substrate wafer can be carried out without the need for cleaning. The cleaning process is reduced to one song. In addition, even if the cutting speed of the substrate wafer by grindstone processing or laser processing is increased, the cutting depth is shallow, so it is possible to suppress the occurrence of defects such as chipping, and the processing time can be shortened. Cost reduction can be achieved.

[Effects of the Invention] As explained above, the method for manufacturing a thin film magnetic transducer of the present invention involves forming grooves along the thin film pattern of the substrate and then grinding the back surface of the substrate to form grooves for each thin film pattern. Since the substrate is divided, processing time during chip cutting can be shortened.

[Brief explanation of the drawing]

1 to 4 are diagrams for explaining a method of manufacturing a thin film magnetic transducer according to an embodiment of the present invention, and FIG.
7 to 7 are diagrams for explaining a conventional method for manufacturing a thin film magnetic transducer, FIG. 8 is a diagram for explaining defective parts in a conventional method for manufacturing a thin film magnetic transducer, and FIG. The figure is a diagram for explaining another conventional method of manufacturing a thin film magnetic transducer. 11... Thin film pattern, 12... Substrate wafer, 13
...Groove, 15...chip. Applicant Toshiba Corporation Toshiba Audio/Video Engineering Co., Ltd. Agent Patent Attorney Sasa Suyama −

Claims (1)

[Claims] A substrate on which a large number of thin film patterns are formed is machined with grooves of a predetermined depth from the surface of the substrate so as to divide each of the thin film patterns, and then, by grinding the back surface of the substrate, each of the thin film patterns is separated. A method for manufacturing a thin film magnetic transducer, characterized by dividing a substrate.