JPH04102214A - Production of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To allow the complete identification of chips even after cutting by entering chip identification information in the respective chip positions on the rear surface of a substrate prior to cutting of the substrate. CONSTITUTION:The chip identification information 3 is first entered in the respective chip positions on the rear 1a of the substrate 1 by utilizing the rear 1a of the substrate 1. Chip patterns 4 are then formed in the respective chip positions on the front surface 1b in compoliance with the positions on the rear 1a of the substrate 1 where the identification information 3 is entered. The substrate 1 is then cut according to the respective chip positions to form the thin-film magnetic heads (chips) 2. The chip patterns 4 are respectively formed on the front surfaces of the respective heads 2 cut in such a manner and figures are entered as the chip identification information 3 on the rear surface. Then, the identification information 3 within the substrate concerning the respective chips 2 is known from these figures. Thus, the birth of the chips 2 is completely known.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a manufacturing method in which a plurality of chips are formed on one substrate and then cut into individual chips to manufacture a thin film magnetic head. This allows for identification.

[Conventional technology]

A thin-film magnetic head, which is one type of magnetic head, is made by depositing a magnetic layer and a conductive coil using photolithography technology.Due to its manufacturing method, it is faster to manufacture than a bulk head, which is manufactured by machining. In addition to being suitable for mass production and miniaturization, it has features such as low high-frequency loss and low inter-track crosstalk when used with multi-tracks.

The manufacturing method for such thin-film magnetic heads involves simultaneously manufacturing multiple chips on a single substrate, and using a mask with a pattern corresponding to each chip position, each chip is manufactured using photolithography technology. After forming a film at the same time, the chips are cut into individual chips for use.

For example, if multiple chips are simultaneously formed on one substrate 1 and then cut into individual thin film magnetic heads (chips), it is difficult to determine from which position on the substrate each chip was taken. Therefore, the chip cannot be identified and the identity of the chip cannot be determined.

Therefore, as an example of a conventional chip identification method, each chip cut from a plurality of substrates made of 10 pieces is collectively placed in one storage container for management and identification.

In addition, as an example of another identification method, when each chip is formed into a film using photolithography technology, an identification number is written on a mask at the same time as the chip is slammed, and this mask is used to write the identification number on each chip by exposure. , a method is adopted to identify each chip.

[Problem to be solved by the invention]

In this type of identification method using a storage container, it is possible to identify and manage only the lot of each storage container, and each chip can only be identified from one board at most, and it is difficult to identify from which position on the board the chip was taken. The problem is that it is not clear.

Another problem is that once each chip is taken out of the storage container and used, its identity becomes completely unknown.

On the other hand, in the case of an identification method that uses photolithography to write identification symbols at the same time as the chip pattern, it is necessary to determine whether each chip can be identified by reading the written symbols. In reality, only one mask is prepared, so even if it is possible to identify the sampling position from one substrate, it is not possible to identify which substrate it is. There's a problem.

Furthermore, if the pattern of the thin film magnetic head itself becomes complex or the size of the chip itself becomes small, there is a problem that there is no space left for writing identification symbols.

This invention was made in view of the problems of the prior art, and it is possible to write a large amount of information for each chip, such as board identification, specification identification, and identification of each chip on the board, and also because of space constraints. The purpose of this invention is to provide a method for manufacturing a thin film magnetic head that is free from damage.

[Failure to solve the problem]

In order to solve the above-mentioned problems, the present invention provides that when manufacturing a thin film magnetic head by forming a plurality of chips on one substrate, at least before cutting the substrate according to the position of each chip, This feature is characterized in that chip identification information is written at each chip position on the back side.

[For production]

According to this method of manufacturing a thin film magnetic head, each chip position on the back surface of the substrate is determined before, during, or after forming a chip pattern before cutting into each chip. For example, the specification number, wafer identification number, chip identification number within the wafer, etc. can be written in numbers using symbols, making it possible to completely identify the identity of each chip without being limited by the size of the chip pattern. can be known.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a process diagram of an embodiment of the method for manufacturing a thin film magnetic head of the present invention, and shows a case in which 18 thin film magnetic heads (chips) are manufactured at the same time.

In this method of manufacturing a thin film magnetic head, 18
By attaching different identification information 3 to each chip 2, it is possible to identify the position within the board 1, as well as information to identify the identification information and specifications of the board 1 itself, so that the identity of each chip 2 can be identified even when cut. be completely identifiable.

(1) Therefore, as the first step in manufacturing a thin film magnetic head, as shown in FIG. Fill in chip identification information 3 in advance.

As the identification information 3 of this chip 2, for example, 1 is shown in FIG.
As shown in the identification information 3 on the back side 1a of the chip 2, 9
Using digit numbers, the first four digits from the left are used to identify the position of each chip 2 on the board 1, the first two digits are used to indicate the "row", and the last two digits are used to indicate the "column". For example, r0401 is the position information of part A in Figure 1.
Use J.

The next two digits are numbers that identify the specifications of the thin film magnetic head (chip) 2, for example, "35".

Then, the last three digits are numbers that identify the board 1 itself,
For example, let it be r623J.

There are various methods for writing information on the board 1 using a 9-digit number for identifying the chip 2, such as r040135623J, but for example, it is sufficient to use photolithography technology. The information is written by preparing a mask containing information 3 for each chip position and exposing it to light.

In this case, unlike writing the pattern 4 of the chip 2 on the surface 1b of the substrate 1 at the same time, there is no need to prepare many masks containing the highly accurate chip pattern 4, and a mask containing only numbers is sufficient. You can easily prepare one by one.

In addition, other methods for writing identification information include marking with a laser beam or mechanical grooving using a timing saw. In the case of grooving, the position and number of grooves formed instead of numbers may be used. etc. will be used as identification information.

(2) The substrate 1 on which the identification information 3 of each chip 2 has been written in this way is sent to the second step.

In this second step, a chip pattern 4 is formed at each chip position on the front surface 1b in accordance with the position where the identification information 3 is written on the back surface 1a of the substrate 1.

The chip pattern 4 of this thin film magnetic head (chip) 2 is created using photolithography technology as in the past.
As shown in one chip pattern 4 in FIG. 3, which is an enlarged view of part B in FIG. The sandwiched conductor coils and further the upper magnetic layer are sequentially formed to form 18 thin film magnetic heads (chips) 2 at the same time.

For example, if the corner 1c of the substrate 1 is used as the alignment reference, the alignment of the front surface N1a1b for film formation of the chip pattern 4 can be performed using the chip position information 3 on the back surface 1a.
Chip pattern 4 can be formed on surface 1b corresponding to .

(3) The substrate 1 with the chip position information 3 written on the back side 1a and the chip pattern 4 formed on the front side 1b is sent to the third step.

In the third step, the substrate 1 is cut according to the position of each chip, resulting in 18 thin film magnetic heads (chips) 2, as shown in FIG. 1(e).

A chip pattern 4 is formed on the front surface of each thin film magnetic head (chip) 2 cut into 18 pieces in this way, and a different nine-digit number is written as chip identification information 3 on the back side.

Therefore, as explained above, from this 9-digit number, the identification information 3 such as information on the chip position in the board, specification information, and information on the board itself for each chip 2 can be determined, and the identity of the chip 2 can be completely determined. You can know.

Note that the chip identification information is not limited to using nine-digit numbers, grooves, etc., and may be combined with letters such as the alphabet.

In addition, in the above embodiment, the step of writing the identification information was the first step before forming the chip pattern, but the writing of the identification information is performed at least during or after the formation of the chip pattern by cutting into each chip. It is sufficient if it is before the third step.

〔Effect of the invention〕

As specifically explained above with one embodiment, according to the present invention, identification information is written using each chip position on the back side of the substrate, so there is no restriction on the size of the chip pattern. You can enter a lot of information necessary to identify each chip/knob, such as the identification information of the chip position within the wafer, chip specification information, and wafer identification information, without having to receive information.

Therefore, even after cutting, the identity of the chip can be completely traced from this identification information, making it possible to completely identify the chip.

[Brief explanation of drawings]

FIG. 1 is a process diagram of an embodiment of the method for manufacturing a thin film magnetic head of the present invention, and shows a case in which 18 thin film magnetic heads (chips) are manufactured at the same time. FIG. 2 is an enlarged view of section A in FIG. 1. FIG. 3 is an enlarged view of section B in FIG. 1. 1... Board, 1a... Back surface, 1b... Front surface, IC
...Corner, 2...Thin film magnetic head (chip), 3
...Chip identification information, 4...Chip pattern. Applicant Yama Stock

Claims (1)

[Claims] When manufacturing a thin film magnetic head by forming a plurality of chips on one substrate, at least write chip identification information on each chip position on the back surface of the substrate before cutting the substrate according to each chip position. A method for manufacturing a thin film magnetic head, characterized in that: