JP4325206B2 - Identification information recording method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for recording identification information on a plate-like member, and a photomask set used in this method. The present invention is not only suitably used for marking identification information on a ceramic substrate used in a magnetic head or the like, but also applicable when recording identification information on a semiconductor wafer or other plate-like member.
[0002]
[Prior art]
In recent years, thin film magnetic heads having various configurations have been used for magnetic head sliders used in hard disk drive (HDD) devices, tape storage devices, flexible disk drive (FDD) devices, and the like. As a substrate used for such a thin film magnetic head, for example, Al ₂ O _Three -TiC, SiC, ZrO ₂ A sintered substrate having a composition such as a system is used.
[0003]
FIG. 1A shows a typical thin film magnetic head slider 10. The track side of the magnetic head slider 10 has two side rails 11 facing the surface of the magnetic disk, and the surface on which these side rails 11 are formed is called an air bearing surface (ABS). May be. When the magnetic disk is rotated at high speed by a motor or the like while the side rails 11 of the magnetic head slider 10 lightly press the surface of the magnetic disk by the head suspension, an air layer formed on the magnetic disk surface is directly below the air bearing surface of the slider 10. The magnetic head slider 10 is lifted slightly. Thus, the magnetic head slider 10 can perform the recording / reproducing operation so as to “fly” near the surface of the magnetic disk.
[0004]
On one end face of the magnetic head slider 10, a thin film 12 is deposited for magnetic interaction with a recording medium such as a magnetic disk. The thin film 12 is used to constitute an electric / magnetic transducer element. On the other hand, identification information 13 such as a recognition number (serial number) is stamped on the other end face of the magnetic head slider 10 in order to confirm the product type. The method of marking the identification information 13 on the sintered body substrate is disclosed in, for example, Patent Document 1, Patent Document 2, and Patent Document 3.
[0005]
Typically, the magnetic head slider 10 is obtained by cutting a bar 20 as shown in FIG. 1B from a sintered body substrate (wafer) 1 as shown in FIG. Is produced by separating the chip into a large number of chips. The end surface 4 of the wafer 1 shown in FIG. 1C is in a positional relationship parallel to the air bearing surface of the magnetic head slider 10 shown in FIG.
[0006]
The thickness of the wafer 1 (corresponding to the length L of the magnetic head slider 10) becomes thinner and the thickness T of each bar 20 (magnetic head) as the size of the thin film head becomes smaller in order to reduce the size and weight of electronic equipment. (Corresponding to the height of the slider 10) is also getting thinner. For example, in the case of a magnetic head slider called a pico slider, L is about 1.2 mm and T is about 0.3 mm. Of course, it is necessary to reduce the size of characters to be engraved on the magnetic head slider thus miniaturized.
[0007]
Laser marking is widely used for marking the identification information 13. In the case of the laser marking method, the identification information 13 shown in FIGS. 1B and 1C is printed on the back surface 3 of the wafer 1 before being divided into the bars 20. After the printing process, various thin films 12 are laminated on the surface 2 of the wafer 1.
[0008]
Next, a conventional laser marking method will be briefly described with reference to FIG.
[0009]
In the laser marking method, the back surface 3 of the wafer 1 is irradiated with the laser beam 6 converged by the lens 5, whereby the irradiated portion of the wafer 1 is rapidly heated and evaporated. At this time, a small concave portion is formed on the back surface 3 of the wafer 1, and the sintered material constituting the wafer 1 is scattered around, and a part of the sintered material adheres to the wafer 1 again. By scanning the back surface 3 of the wafer 1 with the laser beam 6, a planar pattern of the recesses can be arbitrarily drawn. By forming a concave pattern such as an alphabetic character, a number, or a barcode, various identification information 13 can be written at an arbitrary position on the wafer 1.
[0010]
According to such a laser marking method, (1) scattered matter generated by laser irradiation becomes dust and is adsorbed and accumulated in a print groove and the like, so there is a high risk of contamination. (2) Laser light irradiation As a result, burrs are generated at the edge portion of the print groove, and there is a problem that a step for removing burrs is required.
[0011]
As an identification information recording method that does not cause the above problem, a photolithography method has been developed (Patent Document 4). In the case of photolithography, first, after a resist layer is applied and formed on the back surface 3 of the wafer 1, the resist layer is exposed using a specific photomask, so that a latent image of identification information is formed in a desired region of the resist layer. Written. Thereafter, by developing the exposed resist layer, a pattern corresponding to the identification information is transferred to the resist layer. By etching the wafer using the patterned resist layer as a mask, identification information can be written on the wafer. According to the photolithography method, a pattern to be formed can be thinned, and various identification information can be clearly recorded even in a narrow area.
[0012]
[Patent Document 1]
JP-A-9-81922
[Patent Document 2]
Japanese Patent Laid-Open No. 10-134317
[Patent Document 3]
Japanese Patent Laid-Open No. 11-126311
[Patent Document 4]
JP 2002-75817 A
[0013]
[Problems to be solved by the invention]
However, according to the photolithography method described above, in order to record different identification information for each wafer, it is necessary to prepare different types of photomasks by the number of wafers. A photomask is expensive, and for example, a single photomask may cost several hundred thousand yen. For this reason, in the case of the photolithography method, there is a problem of a large increase in cost due to the price of the photomask required in large quantities.
[0014]
The present applicant has disclosed a technique capable of greatly reducing the number of necessary photomasks in Japanese Patent Application No. 2001-269291. Hereinafter, this technique will be described.
[0015]
The technique disclosed in the specification of Japanese Patent Application No. 2001-269291 is a method of recording different identification information on a plurality of ceramic wafers. In this identification information recording method, the identification information recorded on each wafer is z ₁ Digit (z ₁ Is a natural number) character string A and z ₂ Digit (z ₂ Is represented by a character string group including a character string B of (natural number). Here, as shown in FIG. 3A, a case will be described in which the character string A is composed of a one-digit character A1 and the character string B is composed of two-digit characters B1 and B2. Each of the letters A1, B1, and B2 can take 10 types of numbers from 0 to 9. That is, there are 1000 kinds of identification information composed of the character string A and the character string B from “000” to “999”. In addition, each character which comprises a character string may be what is a code unit which can express identification information, such as not only a number but an alphabet, a kana, a kanji, a symbol.
[0016]
The identification information AB is preferably described in a plurality of regions of each wafer as shown in FIG. 3B, but should be described in one place on each wafer as shown in FIG. 3C. Also good. When the identification information is recorded on the wafer as shown in FIG. 3C, the identification information can be used in each step of performing various manufacturing processes in units of wafers, but after dividing the wafer into a plurality of chip parts, The function of identification information is not exhibited.
[0017]
In order to imprint 1000 kinds of identification information on 1000 wafers using a conventional photolithography method, 1000 photomasks (reticles) are required. In this case, for example, different identification information is assigned to each photomask such that a light-shielding pattern defining a character string “150” is formed on the 150th photomask.
[0018]
On the other hand, in the identification information recording method disclosed in Japanese Patent Application No. 2001-269291, a photomask set including two types of photomasks (a first photomask and a second photomask) is used to form a photoresist layer. By performing the exposure process a plurality of times, it becomes possible to imprint necessary identification information on the wafer with a significantly smaller number of photomasks than in the past.
[0019]
Hereinafter, a photomask used in the identification information recording method will be described with reference to FIGS. 4 (a) and 4 (b).
[0020]
In the first photomask shown in FIG. 4A, a light-shielding pattern that defines the character string A is formed. Here, the “light shielding pattern defining the character string A” means a pattern in which the character portion of the character string A is formed by the opening of the light shielding layer on the photomask. In FIGS. 4A and 4B, the white portion of each photomask is a light shielding layer, and the black character (number) portion is an opening in the light shielding layer.
[0021]
When writing different identification information for each wafer to a plurality of regions in the wafer, the light shielding pattern of the character string A is periodically arranged along the X-axis direction and the Y-axis direction on each first photomask. Is done. In this example, since the character A1 is a number from “0” to “9”, ten types of first photomasks are required. If the character string A is a two-digit number, 100 first photomasks are required corresponding to the character strings “00” to “99”.
[0022]
On the other hand, in the second photomask shown in FIG. 4B, patterns defining characters (for one digit) used in the character string B are periodically arranged along the X-axis direction and the Y-axis direction. This period is the same as the period of the character string A, and the characters on the second photomask are arranged so as to be superimposed on the area (non-exposed area) shielded by the light shielding mask of the first photomask.
[0023]
In the example of FIG. 4, since the first photomask and the second photomask have the same light shielding pattern, the first photomask may also serve as the second photomask. However, the first photomask and the second photomask do not have to have the same light-shielding pattern. For example, the first photomask defines alphabetic characters and the second photomask defines numbers. good.
[0024]
Next, an exposure method performed using the photomask set will be described with reference to FIGS.
[0025]
Here, the first photomask 62 shown in FIG. 5A is used. On the first photomask 62, a light shielding film 62a having a pattern defining the character A1 is provided. Such a photomask is obtained by forming a light-shielding metal film or resin film on a transparent substrate such as glass, and then cutting out the character portion from the film. The opening 62b of the light shielding film 62a has a character shape. In the figure, for the sake of simplification, only the opening 62b related to one piece of identification information is shown, but the openings 62b having the same shape are periodically arranged on the actual photomask 62.
[0026]
Next, as shown in FIG. 5B, a wafer 60 coated with a positive photoresist layer 61 is prepared, and the photoresist layer 61 on the wafer 60 is exposed using a first photomask 62. By this exposure, a latent image (latent image of the character A1) having the shape of the opening 62b that defines the character A1 is formed in each of the plurality of regions of the photoresist layer 61. Specifically, since the region of any one of characters A1 (characters “1” in the drawing) from 0 to 9 is exposed, the photoresist layer 61 is exposed to light transmitted through the opening 62b of the light shielding film 62a. Are partially exposed (FIG. 5C). In FIG. 5C, the exposed portion of the positive photoresist layer 61 is indicated by dots. Due to the nature of the positive resist, the exposed portion of the photoresist layer 61 is dissolved in a developing solution in a later developing step to form an opening. As a result, in this embodiment, the character portion of the photoresist layer 61 is cut out.
[0027]
In performing the above exposure, it is efficient to form a latent image defining the character string A on the entire surface of the wafer 60 using, for example, an aligner.
[0028]
Next, the character string B is recorded before the development process. Specifically, an appropriate second photomask is selected from the ten second photomasks as shown in FIG. 4B, and the latent image of the character B1 is transferred to the resist layer using the selected second photomask. 61. FIG. 6A shows a part of the selected second photomask 63. The second photomask 63 is provided with a light shielding film 63a having a pattern that defines the character of the character string B. An opening 63b having the shape of the letter B1 is formed in the light shielding film 63a.
[0029]
By appropriately aligning the second photomask 63, the position of the character B1 is adjusted to a position having an appropriate relationship with the latent image position of the character A1, and light is irradiated as shown in FIG. To do. Since the area other than the character string A of the photoresist layer 61 is an unexposed area, a latent image having a shape corresponding to the opening 63b of the light shielding film 63a is formed when irradiated with light having a pattern that defines the character B1. It is formed (FIG. 6C).
[0030]
Next, FIG. 7A to FIG. After the exposure step, an appropriate second photomask 64 is selected from the second photomask described above, and a latent image of the character B2 is formed on the resist layer 61 using the selected second photomask 64. The second photomask 64 is provided with a light shielding film a that defines the characters of the character string B. An opening 64b having the shape of the letter B2 is formed in the light shielding film 64a. At this time, by appropriately aligning the second photomask 64, the position of the character B2 is aligned with a position having an appropriate relationship with the latent image position of the character A1, and as shown in FIG. Irradiate light. As a result, the unexposed region of the resist layer 61 is irradiated with light having a pattern defining the character B2, and a latent image having a shape corresponding to the opening 64b of the light shielding film 64a is formed on the resist layer 61. (FIG. 7C).
[0031]
Through the above exposure process, identification information is written in each of the plurality of regions in the photoresist layer 61 as shown in FIG. Thereafter, an exposed portion (dot portion in the figure) is removed from the photoresist layer 61 through a development process, and an opening for defining characters is formed in the photoresist layer 61. FIG. 8A schematically shows a cross section of the photoresist layer 61 after development.
[0032]
A method for recording identification information on the wafer 60 using the patterned photoresist 61 will be described with reference to FIGS.
[0033]
First, the case of the etching method will be described. In this case, the resist-attached wafer 60 is loaded into an etching apparatus (not shown), and an appropriate etchant reacts with the wafer surface. By doing so, as shown in FIG. 8B, the surface portion of the wafer 60 that is not covered by the resist layer 61 is etched, and the character strings A and B are transferred to the wafer 61. For etching, preferable etching conditions are appropriately selected according to the material of the wafer to be etched. In addition to dry etching such as RIE (reactive ion etching) using plasma, wet etching may be performed.
[0034]
The method for recording the identification information on the wafer 60 using the developed photoresist layer 61 is not limited to the etching method described above. As shown in FIG. 8C, the identification information is also obtained by depositing a thin film 65 such as a metal film on the wafer 61 covered with the patterned photoresist layer 61 and then removing the photoresist layer 61. Can be transferred to the wafer 61. Such a method is called “lift-off”, and the thin film 65 deposited on the photoresist layer 61 is removed from the wafer surface together with the resist layer 61. As a result, as shown in FIG. 8D, the thin film 65 remains in the opening (in this embodiment, “character part”) of the photoresist layer 61, and the character part protrudes from the other surface in a convex shape.
[0035]
The identification information can be recorded by methods other than the method of forming irregularities on the wafer surface by an etching method or a lift-off method. As shown in FIG. 8E, the wafer 60 covered with the patterned photoresist layer 61 is irradiated with an energy beam such as an ion beam, thereby modifying the exposed surface area of the wafer 60. However, it is also possible to transfer the identification information to the wafer. Since physical parameters such as reflectance characteristics and conductivity change due to surface modification, the identification information can be reproduced from the wafer by detecting this change.
[0036]
According to the identification information recording method described above, since only one type of character is assigned to each photomask, only the type of character to be used requires a photomask. For example, when the character string B is expressed by 26 alphabets from “A” to “Z”, 26 photomasks are required, but at present, there is a strong demand to further reduce the number of photomasks.
[0037]
The present invention has been made in view of such various points, and a main object thereof is to provide an identification information recording method capable of recording various kinds of identification information on a plate member using a small number of photomasks. .
[0038]
Another object of the present invention is to provide a novel exposure method performed by the identification information recording method and to provide a set of photomasks (photomask set) used in the exposure method.
[0039]
[Means for Solving the Problems]
The method for recording identification information according to the present invention is a method for recording different identification information for a plurality of plate-like members, wherein the identification information is z ₁ Digit string A and z ₂ Character string group including character string B of digits (z ₁ And z ₂ Can be used for the first photomask in which the opening pattern defining the character string A is periodically arranged along the X-axis direction and the Y-axis direction, and the character string B. Providing a second photomask in which opening patterns defining different types of characters are periodically arranged along the X-axis direction and the Y-axis direction; and (b) a positive photoresist on the surface of the plate-like member. (C) forming a latent image of the character string A on the photoresist layer by exposing the photoresist layer using the first photomask; and (d) the step of forming a layer. A second photomask is used to form a latent image of a character that is to constitute the character string B in a predetermined region of the photoresist layer, and a character that does not constitute the character string B is formed in the predetermined region of the photoresist layer. Outside And (e) performing the step (d) as many times as necessary to form all the latent images of the characters constituting the character string B in the predetermined region of the positive photoresist layer. A step of developing the photoresist layer; (f) depositing a film of a material different from the resist layer on the photoresist layer; and (g) removing the photoresist layer. Performing a lift-off of the film, thereby forming a first pattern defining the character string A and the character string B and a second pattern not constituting the character string A and the character string B from the film; including.
[0040]
Another method for recording identification information according to the present invention is a method for recording mutually different identification information for a plurality of plate-like members, wherein the identification information includes a character string B, and (a) a character string A step of providing a photomask in which opening patterns defining different types of characters that can be used for B are periodically arranged along the X-axis direction and the Y-axis direction; and (b) a positive surface on the surface of the plate-like member. Forming a type photoresist layer; and (c) using the photomask, forming a latent image of a character to constitute the character string B in a predetermined region of the photoresist layer; A step of forming non-constituting characters outside the predetermined region of the photoresist layer; and (d) performing the step (c) as many times as necessary so that all the latent images of the characters constituting the character string B are formed. The first positive type (E) depositing a film of a material different from the resist layer on the photoresist layer; (f) forming the resist layer in the predetermined region and then developing the photoresist layer; Removing the photoresist layer to lift off the film, thereby forming a first pattern defining the character string B and a second pattern not forming the character string B from the film; Including.
[0041]
The method for recording identification information according to the present invention is a method for recording different identification information for a plurality of plate-like members, wherein the identification information is z ₁ Digit string A, z ₂ Digit string B and z _Three Character string group (z) including digit character string C ₁ Is an integer greater than or equal to 0, z ₂ And z _Three (A) a first photomask in which opening patterns defining the character strings A and C are periodically arranged along the X-axis direction and the Y-axis direction; Providing a second photomask in which opening patterns defining different types of characters that can be used in the character string B are periodically arranged along the X-axis direction and the Y-axis direction; and (b) the plate-like member. Forming a positive-type photoresist layer on the surface of the substrate, and (c) exposing the photoresist layer using the first photomask, thereby exposing the character to each of the plurality of regions of the photoresist layer. A first exposure step of forming a latent image of a row A and a character string C; and (d) using the second photomask, the region where the character string B is to be formed in each of the plurality of regions, The character string B Forming a latent image of the characters to be formed one digit at a time, and forming a character not forming the character string B outside the predetermined region of the photoresist layer, and (e) the step ( Step d) is performed as many times as necessary to form all the latent images of the characters constituting the character string B in the predetermined area of the positive photoresist layer and then develop the photoresist layer. And (f) depositing a film of a material different from the resist layer on the photoresist layer, and (g) removing the photoresist layer to lift off the film, thereby Forming a first pattern defining the character string A and the character string B from a film, and forming a second pattern that does not constitute the character string A and the character string B.
[0042]
In a preferred embodiment, when the Y-axis direction size of a character that can be used for the character string B is y1 and the Y-axis direction period of the same character is y2 on the photomask, measurement is performed along the Y-axis direction. Different types of m characters (m is an integer of 2 or more) used for the character string B are arranged in the section with the distance y2, and the relationship m ≦ y2 / y1 is established.
[0043]
In a preferred embodiment, on the photomask, when the X-axis direction size of a character that can be used for the character string B is x1, and the X-axis direction period of the same character is x2, measurement is performed along the X-axis direction. Different kinds of m ′ characters (m ′ is an integer of 2 or more) used for the character string B are arranged in the section of distance x2, and the relationship m ′ ≦ x2 / x1 is established. .
[0044]
In a preferred embodiment, the method further includes a step of removing at least a part of the second pattern.
[0045]
In a preferred embodiment, the character string B has two or more digits, and the step (d) includes forming a latent image of characters constituting the character string B one digit at a time in the photoresist layer.
[0046]
In a preferred embodiment, a latent image of characters constituting the character string B is formed on the photoresist layer one digit at a time using different portions of the same photomask.
[0047]
In a preferred embodiment, the second photomask is aligned with the photoresist layer so that a selected character on the second photomask is projected at a predetermined position.
[0048]
In a preferred embodiment, the method further includes a step of forming an alignment mark before forming the photoresist layer on the surface of the plate-like member, and the alignment step is performed using the alignment mark.
[0049]
In a preferred embodiment, when performing the exposure, a mask aligner is used to form a latent image of the character string on the entire surface of the photoresist layer.
[0050]
In a preferred embodiment, when the exposure is performed, a latent image of the character string is sequentially formed on a plurality of divided regions of the photoresist layer using a stepper.
[0051]
In a preferred embodiment, the character string C is composed of a character string that is different for each of the plurality of regions of the resist layer.
[0052]
In a preferred embodiment, the plurality of regions are arranged in a matrix composed of rows and columns, and are assigned to regions located in the Mth row and the Nth column (M and N are natural numbers) among the plurality of regions. Character string C _MN When M ≠ J and / or N ≠ K (J and K are natural numbers), _MN ≠ C _JK Is established.
[0053]
In a preferred embodiment, a character string A assigned to an area located in the Mth Nth column (M and N are natural numbers) among the plurality of areas is defined as A. _MN When M ≠ J and / or N ≠ K (J and K are natural numbers), _MN = A _JK Is established.
[0054]
In a preferred embodiment, in the first exposure step, a latent image of the character string A and the character string C is formed on the entire surface of the photoresist layer using a mask aligner.
[0055]
In a preferred embodiment, in the second exposure step, a latent image of the character string B is sequentially formed in each of a plurality of wider areas each including a plurality of areas of the photoresist layer using a stepper. .
[0056]
In a preferred embodiment, the character string B is composed of different character strings for each of the wider areas.
[0057]
The method of manufacturing an electronic component according to the present invention includes a step of preparing the plate-like member in which identification information is recorded by any one of the above methods, a step of depositing a thin film on a selected surface of the plate-like member, Dividing the plate-like member into a plurality of divided parts.
[0058]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0059]
(Embodiment 1)
First, a first embodiment of the identification information recording method according to the present invention will be described.
[0060]
In this embodiment, mutually different identification information is recorded on a plurality of ceramic wafers. The identification information recorded on each wafer is z ₁ Digit (z ₁ Is an integer greater than or equal to zero) character string A and z ₂ Digit (z ₂ Is represented by a character string group including a character string B of 1 or more integers.
[0061]
Here, the character string A indicates information indicating a character string indicating, for example, a wafer type or a company name, and indicates information common to a certain group of wafers, but the character string B indicates information different for each wafer. Shall.
[0062]
Hereinafter, for simplification, a case will be described in which the character string A is 0 digits and the character string B is composed of characters B1, B2, and B3 having three digits. Each of the characters B1 to B3 can take 10 types of numbers from 0 to 9. That is, there are 1000 kinds of identification information composed of the character string B, “000” to “999”. In addition, each character which comprises a character string may be what is a code unit which can express identification information, such as not only a number but an alphabet, a kana, a kanji, a symbol.
[0063]
First, FIG. 9A (a) is referred.
[0064]
FIG. 9A (a) schematically shows a part of the photomask 90 used in this embodiment. The photomask 90 is formed with a light-shielding film (shown in the cross-hatched area), and the area where the light-shielding film does not exist (light transmission area) defines each character that can constitute the character string B. is doing.
[0065]
The characters (cutout portions) on the photomask 90 are periodically arranged along the X-axis direction and the Y-axis direction. In this example, characters “1” to “3” are arranged on one photomask 90. When ten characters “0” to “9” are used as the character B1, ten characters “0” to “9” may be arranged on one photomask, or two or more characters may be arranged. Ten pieces from “0” to “9” may be divided and arranged on the photomask.
[0066]
FIG. 11 shows the size of characters on the photomask 90 and the arrangement pitch of the same characters. FIG. 11 shows a part of the arrangement of the character “1” selected representatively. The character “1” has a size of x1 in the X-axis direction and is periodically arranged at a pitch of x2. The character “1” has a size of y1 in the Y-axis direction and is periodically arranged at a pitch of y2.
[0067]
In the photomask 90 used in the present embodiment, characters “2” and “3” exist between two characters “1” adjacent in the Y-axis direction. Each of the characters “2” and “3” has a size of x1 in the X-axis direction and is periodically arranged at a pitch of x2, has a size of y1 in the Y-axis direction, and is periodically arranged at a pitch of y2. Has been. That is, in this photomask, three different types of characters used for the character string B are arranged in a section whose distance measured along the Y-axis direction is y2. The present invention is not limited to this case, and different types of m characters (m is a natural number of 2 or more) used for the character string B are arranged in a section where the distance measured along the Y-axis direction is y2. May be. Here, the relationship of m ≦ y2 / y1 is established.
[0068]
In the photomask 10 shown in FIG. 9A (a), no other character exists between two characters “1” adjacent in the X-axis direction.
[0069]
Next, refer to FIG. 9A (b). This figure schematically shows an upper surface and a cross section of a wafer 92 to which a positive photoresist 91 is applied and exposure using a photomask 90 is performed. A latent image of the character B1 constituting the character example B is formed in a portion of the positive photoresist 91 irradiated with light transmitted through the opening of the light shielding film in the photomask 90. Note that the latent image formed on the photoresist 91 need not have the same size as the characters on the photomask 90. When recording fine characters on the wafer 92, the pattern of the photomask 90 is preferably reduced and projected onto the photoresist 91 by the optical system of the exposure apparatus.
[0070]
FIG. 9A (b) shows a rectangular area surrounded by a broken line. This rectangular area is an area in which identification information (in this case, the character string B) is to be recorded, and is assigned to each of a large number of chips that are finally separated from the wafer. In the illustrated example, a latent image of the character “1” is formed in a rectangular area. That is, in this example, the character B1 is “1”. In order to form a latent image of the character “1” in the rectangular area, light transmitted through the opening defining the character “1” on the photomask 90 is incident on a predetermined portion in the rectangular area. It is necessary to perform mask alignment.
[0071]
The latent image of characters (“2” and “3”) other than “1” is simultaneously formed on the photoresist 91 by the exposure, but the latent image is located outside the rectangular area.
[0072]
Next, FIG. 9A (c) is referred. FIG. 9A (c) schematically shows an upper surface and a cross section of the wafer 92 after performing exposure for forming a latent image of the character B2 constituting the character string B. FIG. In the illustrated example, the character B2 is “3”. Since the character “3” is defined in the photomask 90 of FIG. 9A, a latent image of the character “3” can be formed in the photoresist 91 using the photomask 90. However, mask alignment is performed so that light transmitted through the opening defining the character “3” of the photomask 90 is incident on a predetermined portion of the rectangular area of the photoresist 91. Specifically, the positional relationship between the photomask 90 and the wafer 92 is determined so that the latent image of the character “3” is formed next to the latent image of the character “1”.
[0073]
Next, as shown in FIG. 9B (a), a latent image of the character B3 is formed on the photoresist 91. In the illustrated example, the character B3 is “2”. Since the character “2” is also defined in the photomask 90 of FIG. 9A, a latent image of the character “2” can be formed in the photoresist 91 using this photomask 90. Mask alignment is performed so that light transmitted through the opening defining the character “2” of the photomask 90 is incident on a predetermined portion of the rectangular area of the photoresist 91. Specifically, the positional relationship between the photomask 90 and the wafer 92 is determined so that the latent image of the character “2” is formed next to the latent image of the character “3”.
[0074]
By repeating the above exposure process one digit at a time, not only a latent image of the character string B but also an unnecessary latent image of a character string other than the character example B is formed on the photoresist 91.
[0075]
Next, the photoresist 91 is developed and the exposed portion is removed, thereby forming a resist pattern 91a in which the exposed portion is hollowed out as shown in FIG. 9B (b). Since the photoresist 91 to be exposed is a positive type, the character portion is constituted by the opening of the resist pattern 91a.
[0076]
Next, as shown in FIG. 9B (c), a film 93 formed of a metal such as Cr, Cu, Ti, Al or the like is deposited on the resist pattern 91a. The thickness of the metal film 93 is set in the range of 5 nm to 1 μm, for example, and is deposited by sputtering or other thin film deposition methods. A part of the metal film is in contact with the surface of the wafer 92 through the opening of the resist pattern 91a. The material of the film 93 is not limited to metal, and may be ceramics.
[0077]
Next, as shown in FIG. 9B (d), the resist pattern 91a is removed, and the metal film 93 is lifted off. By this lift-off, a portion of the metal film 93 that exists on the resist pattern 91 a is selectively removed, and a portion that exists in the opening of the resist pattern 91 a remains on the wafer 92. In this way, metal patterns 93a to 93c having shapes corresponding to the shapes of the openings of the resist pattern 91a are obtained.
[0078]
Next, as shown in FIG. 9C (a), a mask 94 that selectively covers a portion (93a) defining the character string B among the metal patterns 93a to 93c is formed on the wafer 92. The mask 94 is preferably produced by exposing and developing a newly applied photoresist.
[0079]
As shown in FIG. 9C (b), after removing portions of the metal patterns 93a to 93c that are not covered with the mask 94, the mask 94 is removed as shown in FIG. 9C (c). The removal of unnecessary metal patterns is preferably performed using a chemical solution that selectively dissolves the metal patterns so as not to etch the surface of the wafer 92.
[0080]
Through the above steps, the character string B (metal pattern 93a) arranged at a predetermined interval can be formed on the surface of the wafer 92.
[0081]
According to the present embodiment, various types of characters can be formed on the wafer 92 with one photomask 90. If the size of each character is made sufficiently smaller than the arrangement pitch of the identification information, it is possible to arrange all of the characters constituting the identification information on one photomask.
[0082]
In this embodiment, unnecessary characters that do not constitute identification information are removed from the wafer 92, but such characters need not be removed. For example, as shown in FIG. 9D (a), characters that do not constitute identification information may be selectively covered with some mask 95. The mask 95 can be formed by, for example, a mask material film deposition process, a photolithography process, an etching process, or the like. In this case, it is necessary to expose the characters constituting the identification information by etching the mask material film. For this reason, it is preferable that the mask material film has an etching characteristic different from that of the metal film used for forming the characters constituting the identification information. This is because, when patterning the mask, it is desirable that the portion of the mask material film covering the characters constituting the identification information is selectively etched and the characters constituting the identification information are hardly etched. The mask 95 is not removed even after the chip is divided from the wafer 92, and remains uncovered with unnecessary characters.
[0083]
Also, as shown in FIGS. 9D (b) and 9D (c), even if characters that do not constitute identification information remain in a state where they can be visually recognized, they can be distinguished from the characters that constitute identification information. no problem. In the example of FIG. 9D (b), a special pattern 96 is formed in an area where identification information is written or in the vicinity thereof. In the example of FIG. 9D (c), a pattern 97 surrounding the identification information is formed. Such patterns 96 and 97 can be formed by adding a deposition process of metal and other films, a photolithography process, an etching process, and the like. These steps may be performed before or after the character string pattern constituting the identification information is formed.
[0084]
Furthermore, as shown in FIG. 9D (d), a special pattern 98 may be formed on characters that do not constitute identification information. The formation of the pattern 98 may be performed before or after the character string pattern constituting the identification information is formed. Further, as shown in FIG. 9D (e), even if only a part of characters that do not constitute the identification information is processed or removed, it can be distinguished from the characters that constitute the identification information. In the case where only a part of characters that do not constitute identification information is processed or removed, a mask having a pattern obtained by modifying the pattern of the mask 94 shown in FIG. 9C (b) may be formed, and then the metal film may be etched. In the example shown in FIG. 9C (b), characters that do not constitute identification information are completely removed. However, even if a part of unnecessary characters remains, there is no problem if it is not mistaken for identification information.
[0085]
In addition, when including the character string A in identification information, the photomask which prescribes | regulates the character string A is prepared. The photomask that defines the character string A can be used in common for many wafers. For this reason, even when the character string A is composed of a plurality of characters, the character string A itself may be periodically arranged on one photomask, and for each digit of the characters constituting the character string. There is no need to perform exposure.
[0086]
When the character string A is composed of a plurality of characters, for example, the characters A1 and A2, the characters A1 and A2 do not need to be arranged adjacent to each other on the wafer. The characters A1 and A2 may be arranged so as to sandwich the character string B therebetween. When the character string A is composed of a plurality of characters A1 to An, the characters A1 to An do not need to be arranged in a line on a straight line. The characters A1 to An may be divided into rows and columns and arranged two-dimensionally, or may be arranged on a curve. With regard to these character arrangement forms, the character string B is the same as the character string A.
[0087]
When such a character string A is formed on the wafer, patterns as shown in FIGS. 9D (b) to 9 (d) may be formed at the same time. Alternatively, the identification information can be distinguished from other unnecessary character strings by using the character string A itself. In other words, if the character string A is formed only in the area where the identification information is recorded, the character string B constituting the identification information can be distinguished from other unnecessary character strings based on the presence of the character string A. Is possible.
[0088]
(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIGS. 10A to 10C.
[0089]
FIG. 10A shows the layout of the photomask 100 used in this embodiment. Also in this embodiment, the size of characters on the photomask 100 and the arrangement pitch of the same characters are defined as shown in FIG.
[0090]
In the photomask 100 used in the present embodiment, m types (m is a natural number of 2 or more) of different types used for the character string B are arranged in a section whose distance measured along the Y-axis direction is y2. In addition, m ′ characters (m ′ is a natural number of 2 or more) of different types used for the character string B are arranged in the section whose distance measured along the X-axis direction is x2. . Here, the relationship of m ≦ y2 / y1 and m ′ ≦ x2 / x1 is established.
[0091]
FIG. 10B shows a planar layout of a pattern formed on the wafer 101 using the photomask 100 described above. A character string B constituting identification information is written in a rectangular area surrounded by a broken line. In this example, by performing the exposure process using the photomask 100 three times, a character string composed of three characters “1”, “3”, and “5” is recorded as identification information.
[0092]
As is apparent from FIG. 10B, the wafer 101 has many character examples that do not constitute identification information. In the first embodiment, an unnecessary character string does not exist between the character strings that constitute two pieces of identification information adjacent along the X-axis direction, but in this embodiment, at such positions. There is also an unnecessary character string.
[0093]
An unnecessary character example can be removed as shown in FIG. 10C by executing a process similar to the process performed in the first embodiment. Of course, all or part of the unnecessary character string may be left on the wafer 101 by performing the various methods described with reference to FIG. 9D.
[0094]
According to this embodiment, more types of characters can be arranged on one photomask. This embodiment is particularly effective in the case where identification information consisting of fine character strings is recorded on the wafer with a sufficient interval.
[0095]
In addition, when including the character string A in identification information, the photomask which prescribes | regulates the character string A is prepared. The pattern as shown in FIGS. 9D (b) to 9 (d) may be formed together with the character string A by using a photomask for forming the character string A, as in the first embodiment. is there.
[0096]
(Embodiment 3)
In this embodiment, the identification information recorded on each wafer is z ₂ Digit string B and z _Three Digit string C (z ₂ And z _Three Is an integer of 1 or more.
[0097]
Here, an example in which identification information is configured using a character string C that differs depending on the position in the wafer will be described. If different identification information is given to a plurality of regions in the wafer, when a plurality of divided parts are cut out from one wafer as shown in FIG. 1, unique identification information can be assigned to each divided part.
[0098]
In order to simplify the description, a case where the 4-digit identification information shown in FIG. The character string B in this identification information is composed of two-digit characters B1 and B2, and the character string C is composed of two-digit characters C1 and C2. Here, it is assumed that each of the characters B1 and B2 can take 26 types of alphabet symbols from a to z, and each of the characters C1 and C2 can take 10 types of numbers from 0 to 9. That is, the identification information composed of the character strings B and C is 26 of “aa00” to “zz99”. ² × 10 ² There are streets. The two-digit character string C can be used, for example, to give different identification information to a region of 10 rows × 10 columns (= 100) arranged in a matrix. FIG. 12B schematically shows the wafer surface on which the identification information is recorded. If the number of digits of the character string C is increased, different identification information can be given to a larger number of areas.
[0099]
FIG. 12B schematically shows the wafer surface when unnecessary character strings that do not constitute identification information are removed. The actual interval of the identification information is wider than the illustrated interval, and an unnecessary character string is formed in the interval portion.
[0100]
In this specification, a character string C assigned to an area located in the Mth row and the Nth column (M and N are natural numbers) among a plurality of areas arranged in a matrix is defined as C. _MN Indicate. That is, C1 · C2 = C _MN It is. In this embodiment, if M ≠ J and / or N ≠ K (J and K are natural numbers), C _MN ≠ C _JK Is established. If such a character string C is seen, the identification information assigned to which row and column position of the wafer can be known. Therefore, the character string C is referred to as a “matrix number (column row number)”. When the wafer is divided into a plurality of parts, if the identification information is stamped on each divided part, it is specified from which part of which wafer the divided part is cut out.
[0101]
Hereinafter, the photomask used in this embodiment will be described with reference to FIG.
[0102]
In the first photomask in the present embodiment, a light shielding pattern that defines the character of the character string C is formed. Here, the “light-shielding pattern defining the character of the character string C” means a pattern in which the character portion of the character string C is formed by the opening of the light-shielding layer on the photomask. On the first photomask, the opening pattern of the character string C is periodically arranged along the X-axis direction and the Y-axis direction.
[0103]
The difference between the character string A and the character string C of this embodiment is that the two-digit character string C has different values depending on the position of one wafer. Further, the character string C need not have a different value for each wafer. Therefore, one type of photomask for writing the character string C is sufficient.
[0104]
On the other hand, the second photomask has the same configuration as the photomask 90 used in the first embodiment and the photomask 100 used in the second embodiment. By using such a second photomask, the characters “a” and “b” shown in FIG. 12B are written to the resist layer one digit at a time.
[0105]
Next, the exposure method in this embodiment will be described.
[0106]
First, a wafer coated with a positive photoresist layer is prepared, and each of a plurality of regions of the photoresist layer is exposed using a first photomask. By this exposure, latent images of the character string C (“00” to “99”) are formed at different positions on the resist layer.
[0107]
Next, a latent image of the character B1 is formed on the resist layer using a photomask similar to the photomask used in the first or second embodiment. At this time, by appropriately aligning the photomask, the position of the character B1 is aligned with the position of the latent image of the character string C, and the unexposed portion of the positive resist layer is irradiated with light. At this time, as described above, an unnecessary character latent image that does not constitute identification information is also formed in the photoresist.
[0108]
Further, a latent image of the character B2 is formed on the resist layer using a photomask similar to the photomask used in the first or second embodiment. At this time, by appropriately aligning the photomask, the position of the character B2 is aligned with the position of the latent image of the character string C, and the unexposed portion of the resist layer is irradiated with light. At this time, a latent image of unnecessary characters that do not constitute identification information is also formed on the photoresist.
[0109]
By the above method, the character string B, the character string C, and unnecessary characters are written in each of the plurality of regions in the positive resist layer. Thereafter, the exposed portion is removed from the resist layer through a development step, whereby the character portion is cut out from the resist layer. Subsequent steps can be performed in the same manner as in the first and second embodiments.
[0110]
Although the character string A is not included in the identification information, the character string A may be included. In this case, the photomask for the character string A can also be used as the first photomask for the character string C. However, in that case, it is necessary to form an opening pattern for defining the character string C in the light-shielding film of the photomask used for forming the character string A. On the other hand, the photomask for forming the character string C and the photomask used for forming the character string A may be separated.
[0111]
(Embodiment 4)
Hereinafter, the identification information is z ₁ Digit string A, z ₂ Digit string B and z _Three Character string group (z) including digit character string C ₁ Is an integer greater than or equal to 0, z ₂ And z _Three Is an integer represented by 1).
[0112]
In this embodiment, as shown in FIG. 13, a plurality of regions forming the character string ABC are gathered to form one cluster region. A plurality of cluster areas are assigned to one wafer, and a different character string B is assigned to each cluster area. Specifically, the area of the Mth row and the Nth column in the Lth cluster area on one wafer has a character string A _MN B _L C _MN The identification information expressed by is recorded. Here, L is an integer. String A _MN B _L C _MN Character string C _MN Is the same for different cluster areas, but the string B _L Is different for each cluster area. For this reason, the character string B _L Thus, the cluster area can be specified, and the position in each cluster area can be specified by the character string C.
[0113]
In each cluster region, when M ≠ J and / or N ≠ K (J and K are natural numbers), A _MN ≠ A _JK May be satisfied, or A _MN = A _JK May be established. The character string A expresses information for identifying the wafer. String C _MN For M ≠ J and / or N ≠ K (where J and K are natural numbers), C _MN ≠ C _JK Therefore, the identification by the position in each cluster is the character string C _MN The string A depending on the position in the cluster. _MN There is no need to change
[0114]
Note that the arrangement order of the character string A, the character string B, and the character string C and the arrangement form of the cluster areas are not limited to the example shown in FIG.
[0115]
In the present embodiment, a first exposure process for forming a latent image of the character string A and the character string C is performed on each of the plurality of regions of the positive photoresist layer using the first photomask.
[0116]
Thereafter, a second exposure step is performed for forming a latent image of characters constituting the character string B one digit at a time for the unexposed portion of the positive resist. The second exposure process is performed by the number of digits of the character string B. String B _L Need not be a single digit.
[0117]
In the first exposure step, it is preferable to form the latent images of the character strings A and C on the resist layer on the entire surface of the wafer using an aligner. On the other hand, in the second exposure step, it is preferable to expose the character string B for each cluster region using a stepper. The latent images of the character string A and the character string C may be formed separately using different photomasks.
[0118]
Also in this embodiment, when performing the exposure process of the character string B, the photomask shown to FIG. 9A (a) and the photomask shown to FIG. 10A are used. For this reason, an unnecessary character string is formed, but the unnecessary character string can be removed as in the other embodiments.
[0119]
Pattern alignment (alignment) using each photomask is performed with reference to an alignment mark formed on the wafer. For example, an alignment mark as shown in FIG. 14A is formed on the wafer in advance. Such an alignment mark is preferably formed from a resist pattern. On the other hand, the first photomask and the second photomask are provided with other alignment marks to be superimposed on the alignment marks. As alignment marks provided on the photomask, it is preferable to employ a plurality of patterns as shown in FIG. If alignment marks as shown in FIG. 14B are employed, mask alignment can be performed with high accuracy.
[0120]
The plate-like member to which the present invention is applied is not limited to a ceramic wafer, and the material thereof is arbitrary. Further, the plate-like member is not limited to a wafer and may be any member as long as it has a two-dimensionally spread surface on which identification information is written. The surface on which the identification information is written need not be a flat surface, and may be a curved surface. The identification information is desirably written in a flat area, but it is not necessary that the entire surface of the plate-like member is flat. Any irregularities or steps may already be formed in the area other than the area where the identification information is written.
[0121]
When writing identification information on a ceramic wafer or silicon wafer, recording of the identification information is not limited to being performed before starting a process of depositing various thin films on the wafer. The identification information can be recorded on the wafer at any stage during or after the series of thin film deposition and patterning processes.
[0122]
The identification information may be formed on the front side of the wafer (on the side where the patterned magnetic film is disposed) instead of being formed on the leading side of the back side of the wafer as shown in FIG. good.
[0123]
When a magnetic head slider is formed from a ceramic substrate (ceramic wafer), an element (transducer element) for recording / reproducing data on a recording medium is formed on the front surface side (trailing edge side) of the wafer. Is done.
[0124]
When data recording / reproducing elements (electric / magnetic transducer elements) and terminals are formed on the front side of the wafer, the identification information is lost even if the substrate is thinned by polishing the back side of the wafer. There is an advantage that it does not occur.
[0125]
The identification information is recorded at a position where light (reading light) irradiated on the substrate to read the identification information can reach (for example, a position where a member capable of blocking light such as an electric / magnetic transducer element is not formed). For example, since the identification information is expressed by a pattern having a line width of about several μm, the area required for recording the identification information may be small. For this reason, it is possible to secure a vacant area on the substrate surface on which the patterned magnetic film, terminals, and the like are formed in order to record identification information.
[0126]
FIG. 15 is a plan view showing a part of the wafer surface, and FIG. 16 is an enlarged plan view showing a region corresponding to one chip on the substrate surface.
[0127]
As can be seen from FIG. 15, the substrate surface is partitioned into a plurality of regions 46 each corresponding to the chip substrate of the magnetic head. In FIG. 16, eight complete regions 46 are described. This substrate is finally separated along the boundary line of each region 46, and a large number of chip substrates are produced from one substrate (wafer). One chip substrate shown in FIG. 16 corresponds to one region 46, and each region 46 on the substrate has a rectangular region 45 in which identification information is recorded. In the hatched area of FIG. 16, a magnetic film, a terminal, and the like constituting an electric / magnetic transducer element are described. As a result, the reading light can be applied to the identification information. Even if a part of the members constituting the electric / magnetic transducer element and other elements exists at a position covering the identification information, there is no problem as long as the member transmits the reading light.
[0128]
Thus, when recording identification information on the surface of a wafer, the area where the identification information is written is limited to a relatively narrow range, and these areas are discretely arranged as shown in FIG. For this reason, the embodiment using a photomask as shown in FIG. 10A can be suitably applied.
[0129]
【The invention's effect】
According to the present invention, various kinds of identification information can be recorded on a plate-like member using a small number of photomasks, and an increase in manufacturing cost due to the price of the photomask can be greatly suppressed.
[0130]
The present invention is suitably applied to a manufacturing method in which a plurality of parts are cut out from a plate-like member such as a wafer. In particular, according to the present invention, it is possible to manufacture a thin film magnetic head substrate having identification information recorded on the front surface side (trailing edge side) instead of the back surface side (leading edge side) with a small number of photomasks. .
[Brief description of the drawings]
1A is a perspective view of a slider for a magnetic head, FIG. 1B is a perspective view showing a bar before the magnetic head slider is separated, and FIG. 1C is a rectangular sintered body substrate; FIG.
FIG. 2 is a diagram schematically showing a laser marking process.
3A is a diagram showing identification information, and FIGS. 3B and 3C are diagrams showing different identification information recorded on a plurality of wafers. FIG. (B) shows a case where identification information is recorded at one location of each wafer, and (c) shows a case where identification information is written at a plurality of locations on each wafer.
4A schematically shows a configuration of a first photomask in Embodiment 1, and FIG. 4B schematically shows a configuration of a second photomask.
5A is a plan view showing a part of the first photomask in Embodiment 1, and FIGS. 5B and 5C show a first exposure process performed using the first photomask. It is sectional drawing.
6A is a plan view showing a part of a second photomask in Embodiment 1, and FIGS. 6B and 6C show a second exposure step performed using the second photomask. It is sectional drawing.
7A is a plan view showing a part of a second photomask in Embodiment 1, and FIGS. 7B and 7C show a second exposure process performed using the second photomask. It is sectional drawing, (d) is a top view which shows the resist layer after an exposure process.
FIGS. 8A to 8E are process cross sections showing a method of recording identification information on a wafer having a developed resist layer. FIGS. (A) shows the wafer immediately after development, and (b) shows the wafer after etching. (C)-(d) shows the lift-off method, and (e) shows the surface modification method.
9A is a plan view showing the configuration of a photomask that can be used in the first embodiment of the identification information recording method of the present invention, and FIG. 9B and FIG. 9C show the first embodiment. It is a figure which shows the wafer in the process of form.
FIGS. 9A to 9D are views showing a wafer in the process of the first embodiment. FIGS.
FIGS. 9A to 9C are views showing a wafer in the process of the first embodiment. FIGS.
FIGS. 9A to 9E are plan views showing an example in which a character string constituting identification information is distinguished from other unnecessary character strings, respectively.
FIG. 10A is a plan view showing a configuration of a photomask that can be used in the second embodiment of the identification information recording method of the present invention;
FIG. 10B is a plan view showing the wafer surface in the process of the second embodiment.
FIG. 10C is a plan view showing a character string B formed on the wafer surface in the second embodiment.
FIG. 11 is a plan view showing character sizes and arrangement pitches on a photomask that can be used in an embodiment of the present invention.
12A is a diagram showing one piece of identification information used in Embodiment 3, FIG. 12B is a plan view showing a wafer in which the identification information is written, and FIG. It is a figure which shows the structure of the 1st photomask used in Embodiment 3. FIG.
FIG. 13 is a plan view schematically showing a configuration of a character string group used in the fourth embodiment.
FIGS. 14A and 14B are layout diagrams showing the configuration of alignment marks. FIGS.
FIG. 15 is a plan view showing a part of the wafer surface.
FIG. 16 is an enlarged plan view showing a region corresponding to one chip on the wafer surface;
[Explanation of symbols]
1 Ceramic wafer (sintered substrate)
2 surface
3 Substrate back
4 Board end face
5 Lens
6 Laser beam
10 Magnetic head slider
11 Side rail of air bearing surface (ABS)
12 Laminated thin film from the substrate surface
13 Identification information (ID or ID mark)
20 bar

Claims (19)

A method of recording different identification information for a plurality of plate-like members,
The identification information is a character string group including a character string A of z ₁ digits and a character string B of z ₂ digits (z ₁ and z ₂ are integers of 1 or more),
(A) A first photomask in which opening patterns defining the character string A are periodically arranged along the X-axis direction and the Y-axis direction, and opening patterns defining different types of characters that can be used in the character string B Preparing a second photomask in which are periodically arranged along the X-axis direction and the Y-axis direction;
(B) forming a positive photoresist layer on the surface of the plate-like member;
(C) forming a latent image of the character string A on the photoresist layer by exposing the photoresist layer using the first photomask;
(D) The second photomask is used to form a latent image of the character to constitute the character string B in a predetermined region of the photoresist layer, and characters that do not constitute the character string B are formed to the photoresist layer. Forming outside the predetermined region of
Including
(E) By performing the step (d) as many times as necessary, all the latent images of the characters constituting the character string B are formed in the predetermined region of the positive photoresist layer, and then the photoresist Developing the layer,
(F) depositing a film of a material different from the photoresist layer on the photoresist layer;
(G) The film is lifted off by removing the photoresist layer, and thereby the first pattern defining the character string A and the character string B from the film, and the character string A and the character string. Forming a second pattern that does not constitute B;
Including methods. A method of recording different identification information for a plurality of plate-like members,
The identification information includes a character string B,
(A) preparing a photomask in which opening patterns defining different types of characters that can be used in the character string B are periodically arranged along the X-axis direction and the Y-axis direction;
(B) forming a positive photoresist layer on the surface of the plate-like member;
(C) Using the photomask, a latent image of a character that should constitute the character string B is formed in a predetermined region of the photoresist layer, and a character that does not constitute the character string B is formed on the photoresist layer. Forming outside the predetermined region;
Including
By performing many times as necessary (d) is the step (c), after forming the predetermined region of the entire latent image of the characters constituting the character string B before Kipo di photoresist layer, the photo Developing the resist layer; and
(E) depositing a film of a material different from the photoresist layer on the photoresist layer;
(F) The film is lifted off by removing the photoresist layer, whereby a first pattern defining the character string B and a second pattern not constituting the character string B are formed from the film. Forming, and
Including methods. A method of recording different identification information for a plurality of plate-like members,
The identification information includes a character string group including a z ₁ digit character string A, a z ₂ digit character string B, and a z ₃ digit character string C (z ₁ is an integer greater than or equal to 0, z ₂ and z ₃ are 1). (Integer)
(A) A first photomask in which opening patterns defining the character string A and the character string C are periodically arranged along the X-axis direction and the Y-axis direction, and different types of characters that can be used for the character string B. Providing a second photomask in which opening patterns to be defined are periodically arranged along the X-axis direction and the Y-axis direction;
(B) forming a positive photoresist layer on the surface of the plate-like member;
(C) A first image in which a latent image of the character string A and the character string C is formed on each of a plurality of regions of the photoresist layer by exposing the photoresist layer using the first photomask. An exposure process;
(D) Using the second photomask, a character latent image forming the character string B is formed one digit at a time in a predetermined region where the character string B is to be formed in each of the plurality of regions. And a second exposure step of forming characters that do not constitute the character string B outside the predetermined region of the photoresist layer;
Including
(E) by performing only the step (d) times as necessary, after forming the predetermined region of the entire latent image of the characters constituting the character string B before Kipo di photoresist layer, the photo Developing the resist layer; and
(F) depositing a film of a material different from the photoresist layer on the photoresist layer;
(G) by removing the photoresist layer was subjected to lift-off of the membrane, whereby said from the membrane strings A, a first pattern defining string B, and the strings C, before Symbol Forming a second pattern not constituting the character string B ;
Including methods.   On the photomask, when the Y-axis direction size of the character that can be used for the character string B is y1, and the Y-axis direction period of the same character is y2, the distance measured along the Y-axis direction is y2. Any of m types (m is an integer of 2 or more) of different types used in the character string B are arranged therein, and a relationship of m ≦ y2 / y1 is established. The method of crab.   On the photomask, when the X-axis direction size of the character that can be used for the character string B is x1, and the X-axis direction period of the same character is x2, the distance measured along the X-axis direction is x2 The m ′ (m ′ is an integer of 2 or more) characters of different types used in the character string B are arranged therein, and the relationship of m ′ ≦ x2 / x1 is established. 5. The method according to any one of 4.   The method according to claim 1, further comprising removing at least a part of the second pattern. The character string B has two or more digits,
The method according to claim 1, wherein the step (d) includes forming a latent image of characters constituting the character string B one digit at a time in the photoresist layer.   The method according to claim 7, wherein a latent image of characters constituting the character string B is formed in the photoresist layer one digit at a time using different portions of the same photomask.   The method according to claim 1, further comprising aligning the photomask with respect to the photoresist layer such that selected characters on the photomask are projected at predetermined positions. .   The method according to claim 9, further comprising forming an alignment mark before forming the photoresist layer on the surface of the plate-like member, and the alignment step is performed using the alignment mark.   11. The method according to claim 8, wherein a latent image of the character string is formed on the entire surface of the photoresist layer using a mask aligner when performing the exposure.   The method according to claim 8, wherein when performing the exposure, a latent image of the character string is sequentially formed on a plurality of divided regions of the photoresist layer using a stepper.   The method according to claim 3, wherein the character string C is composed of a character string that is different for each of the plurality of regions of the photoresist layer. The plurality of regions are arranged in a matrix composed of rows and columns,
When the character string C assigned to the region located in the Mth row and the Nth column (M and N are natural numbers) among the plurality of regions is represented by _CMN , M ≠ J and / or N ≠ K (J and The method according to claim 13, wherein C _MN ≠ C _JK is established, where K is a natural number. When the character string A assigned to the region located in the Mth row and the Nth column (M and N are natural numbers) among the plurality of regions is represented by _AMN , M ≠ J and / or N ≠ K (J and The method according to claim 14, wherein A _MN = A _JK holds, where K is a natural number.   The method according to claim 13, wherein in the first exposure step, a latent image of the character string A and the character string C is formed on the entire surface of the photoresist layer using a mask aligner.   The latent image of the character string B is sequentially formed in each of a plurality of wider areas, each including a plurality of areas of the photoresist layer, using a stepper in the second exposure step. The method in any one of.   The method according to claim 17, wherein the character string B is composed of different character strings for each of the wider plurality of regions. A step of preparing the plate-like member on which the identification information is recorded by the method according to any one of claims 1 to 18,
Depositing a thin film on a selected surface of the plate member;
Dividing the plate-like member into a plurality of divided parts; and
A method of manufacturing an electronic component including:

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