JP2008071379A - Method of manufacturing magnetic head element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a magnetic head element which is excellent in the shielding property and highly sensitive. <P>SOLUTION: The method of manufacturing the magnetic head element having a soft magnetic layer, is characterized in that the method has the steps of: depositing a plating base layer of the soft magnetic layer by sputtering; and applying a magnetic field to the direction parallel with an orientation flat of a wafer in which the head element is formed during the deposition step. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention generally relates to a method for manufacturing a magnetic head element, and more particularly to a method for manufacturing a magnetic head element including a soft magnetic layer such as a shield layer. The present invention is suitable for a read head having a magnetoresistive effect element, for example, used in a hard disk drive (HDD).

  With the recent spread of the Internet and the like, the demand for magnetic disk devices that record large amounts of information including images and videos has increased. When the surface recording density is increased to meet the demand for larger capacity, the area on the 1-bit recording medium, which is the minimum unit of magnetic recording information, is reduced, and the signal magnetic field obtained from the recording medium is weakened. In order to read this weak signal magnetic field, a small and highly sensitive read head is required.

  As such a read head, a read head using a magnetoresistive effect element is conventionally known. In a typical magnetoresistive element, a pair of gap layers is provided between a pair of shield layers, and a magnetoresistive film is provided between the pair of gap layers. The shield layer is formed by electrolytic plating by forming a plated base layer by sputtering and then inserting the plated base layer into an electrolytic solution to pass a current through the plated base layer.

As a prior art, there is, for example, Patent Document 1.
JP-A-5-73842

  In order to realize a high-sensitivity read head, it is preferable to improve the magnetic characteristics of the shield layer that shields the external magnetic field to form one reflux magnetic domain as shown in FIG. At that time, the parallel magnetic domain portions 2a and 2b in the longitudinal direction need to be parallel or anti-parallel to the predetermined direction, and when this is inclined with respect to the predetermined direction, an abnormal magnetic domain is formed and the magnetic characteristics are deteriorated.

  When the shield layer becomes thinner with the miniaturization of the magnetic head, the abundance ratio of the plating base layer in the shield layer increases, and the magnetic characteristics (magnetic anisotropy) of the plating base layer have a great influence on the magnetic characteristics of the magnetic head. Become. On the other hand, Patent Document 1 attempts to improve the magnetic characteristics by performing the shield layer forming process in a magnetic field in paragraph 0014. Furthermore, it has also been proposed to reliably form magnetic anisotropy by heat treatment in a magnetic field after the plating layer is formed. However, since Patent Document 1 does not define the direction of the magnetic field during the film forming step and the direction of the magnetic field during the heat treatment, the magnetic domain portions 2a and 2b are not necessarily parallel or antiparallel to the predetermined direction.

  The present invention provides a method of manufacturing a magnetic head element having excellent shielding characteristics and high sensitivity.

  A manufacturing method as one aspect of the present invention is a method of manufacturing a magnetic head element having a soft magnetic layer, the step of forming a plating base layer of the soft magnetic layer by sputtering, and the step during the film formation step. Applying a magnetic field in a direction parallel to the orientation flat of the wafer on which the head element is formed. A plating base layer having excellent magnetic anisotropy can be formed by applying a magnetic field in parallel with the orientation flat. Thus, if the soft magnetic layer is a shield layer that shields an external magnetic field, the shield layer suppresses variations in magnetic characteristics among products and has high stability against heat and an external magnetic field.

  The method may further include the step of forming the soft magnetic layer by electrolytic plating using the plating base layer, and the step of applying a magnetic field in the direction during the electrolytic plating film forming step. Thereby, a plating layer having excellent magnetic anisotropy can be formed. Moreover, it is preferable to further have a magnetic field heat treatment step of heat-treating the wafer in a magnetic field in the same direction as the direction. By maintaining the magnetic field in the same direction as during film formation in the subsequent heat treatment, it is possible to prevent the magnetic properties from being deteriorated due to the heat treatment.

  Preferably, the manufacturing method further includes a step of applying a magnetic field to the wafer in a direction different from the direction at a normal temperature, and performing the magnetic field heat treatment step after the normal temperature magnetic field application step. By the magnetic field heat treatment step, it is possible to recover from the deterioration of the magnetic characteristics due to the room temperature magnetic field application step. In this case, the magnetic field heat treatment step may be performed at least once after the room temperature magnetic field application step is performed or after the room temperature magnetic field application step is performed a plurality of times.

Preferably, the manufacturing method further includes a step of heat-treating the wafer without a magnetic field, and the magnetic field heat-treatment step is performed after the magnetic-less heat treatment step. By the magnetic field heat treatment step, it is possible to recover from the deterioration of the magnetic properties due to the magnetic field heat treatment step. In that case, the magnetic field heat treatment step may be performed at least once after the execution of the magnetic field heat treatment step or after the magnetic field heat treatment step is performed a plurality of times. The temperature of the magnetic field heat treatment step is preferably equal to or higher than the temperature of the magnetic field heat treatment step. Thereby, it is possible to recover from the deterioration of the magnetic characteristics due to the magnetic field heat treatment step. The magnetic head element is, for example, a combined head element of a write head element and a read head element. Further objects or other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings. Will be done.

  According to the present invention, it is possible to provide a method of manufacturing a magnetic head element having excellent shielding characteristics and high sensitivity.

  Hereinafter, a magnetic head element used in an HDD will be described with reference to the accompanying drawings. The magnetic head element acts from, for example, an induction writing head element (hereinafter referred to as “inductive head element”) that writes binary information on a magnetic disk using a magnetic field generated by a conductive coil pattern (not shown), and a magnetic disk. This is an MR inductive composite head having a magnetoresistive effect (hereinafter referred to as “MR”) head element that reads binary information based on a resistance that changes in accordance with a magnetic field applied.

  In the MR head element, as shown in FIG. 1A, the sense current flows parallel to the laminated surface of the magnetoresistive effect film, and as shown in FIG. 1B, the sense current flows perpendicularly to the laminated surface of the magnetoresistive effect film. Applicable to any type.

The inductive head element 130 is commonly used in FIGS. 1A and 1B. The inductive head element 130 includes a nonmagnetic gap layer 132, an upper magnetic pole layer 134, an insulating film 136 made of Al ₂ O _3, and an upper shield / upper electrode layer 139. However, as will be described later, the upper shield / upper electrode layer 139 also constitutes a part of the MR head element 140.

The nonmagnetic gap layer 132 extends along the surface of the upper shield / upper electrode layer 139 and is made of, for example, Al ₂ O ₃ . The top pole layer 134 is provided on the side opposite to the top shield / upper electrode layer 139 with respect to the nonmagnetic gap layer 132, and is made of, for example, NiFe. The insulating film 136 extends along the surface of the nonmagnetic gap layer 132 and covers the upper magnetic pole layer 134 to form the head element built-in film 123. The insulating film 136 is made of, for example, Al ₂ O ₃ . The upper magnetic pole layer 134 and the upper shield / upper electrode layer 139 cooperate to constitute a magnetic core of the inductive head element 130. The lower magnetic pole layer of the inductive head element 130 functions as the upper shield layer 139 of the MR head element 140. When a magnetic field is generated in the conductive coil pattern, the magnetic flux flowing between the upper magnetic pole layer 134 and the upper shield / upper electrode layer 139 leaks from the air bearing surface 125 by the action of the nonmagnetic gap layer 132. A recording magnetic field (gap magnetic field) is formed by the magnetic flux flowing out in this way.

  The MR head element 140 shown in FIG. 1A has an upper shield layer 139, a lower shield layer 142, an upper gap layer 144, a lower gap layer 146, a spin valve film 150, and a lead terminal portion 160.

The shield layers 139 and 142 are made of NiFe, for example. The gap layers 144 and 146 are made of an insulating material such as Al ₂ O ₃ , for example. 139a and 142a are plating base layers in the shield layers 139 and 142. A plating layer is formed on the plating base layers 139a and 142a to form shield layers 139 and 142. The plating layer is formed by forming a plating base layer by sputtering and then inserting the plating base layer into an electrolytic solution to pass a current through the plating base layer.

  The spin valve film 150 includes a free ferromagnetic layer 152, a nonmagnetic intermediate layer 154, a pin magnetic layer 156, and an exchange coupling layer 158, and constitutes a GMR sensor. The spin valve film 150 may be of any type, such as a top type spin valve, a bottom type spin valve, or a dual spin valve structure.

  The lead terminal portion 160 includes a hard bias layer 162 that generates a bias magnetic field, and a terminal layer 166 that applies a sense current and defines an element width WE. As described above, the MR head element 140 shown in FIG. 1A has a CIP structure in which the sense current is applied parallel to the stack surface of the spin valve film 150 or perpendicular to the stack direction (CIP-GMR element). The hard bias layer 162 includes, for example, a base layer 163 made of Cr, CrTi alloy, TiW alloy, or the like, and a hard layer 164 made of a magnetic material such as a CoPt alloy or a CoCrPt alloy. The terminal layer 166 includes, for example, a base layer 167 made of a nonmagnetic layer such as Ta, an electrode layer 167 made of gold, and a cap layer 169 made of Ta.

  On the other hand, the MR head element 140A shown in FIG. 1B includes an upper shield layer 139, a lower shield layer 142, an upper gap layer 144, a lower gap layer 146, a magnetoresistive effect film 150A, and both sides of the magnetoresistive effect film 150A. And a pair of hard bias films 160A.

The magnetoresistive film 150A is composed of, for example, a TMR film. In this case, in order from the bottom shown in FIG. 1B, a free (ferromagnetic) layer 152A, a (nonmagnetic) insulating layer 154A, a pinned (magnetic) layer 156A, and an antiferromagnetic layer 158A are provided. The TMR film has a ferromagnetic tunnel junction having a structure in which an insulating layer 154 is sandwiched between two ferromagnetic layers. When a voltage is applied between the two ferromagnetic layers, electrons in the − side ferromagnetic layer are insulated. The phenomenon of tunneling through the layer to the + side ferromagnetic layer is used. For the insulating layer 154A, for example, an Al ₂ O ₃ film is used.

  The magnetoresistive film 150A may be a spin valve film. In this case, the MR element is a CPP-GMR element. The spin valve film in this case includes a free layer 152A, a nonmagnetic intermediate layer 154A, a pinned magnetic layer 156A, and an exchange coupling layer (antiferromagnetic layer) 158A in order from the bottom shown in FIG. 1B.

  The hard bias film 160A generates a bias magnetic field that suppresses noise. The hard bias film 160A is made of a magnetic material such as a CoPt alloy or a CoCrPt alloy, for example.

  Hereinafter, a method for manufacturing a magnetic head element will be described with reference to FIGS. Here, FIG. 2 is a flowchart for explaining a method of manufacturing the magnetic head element. Here, the description will focus on the manufacturing of the upper shield layer 139 and the subsequent steps. However, the manufacturing method of this embodiment can also be applied to other soft magnetic layers such as a terminal layer using a plating base layer. First, a plating base layer is formed of NiFe by sputtering (step 1002). At this time, as shown in FIG. 3, a magnetic field is applied in a direction parallel to the orientation flat OF of the wafer W on which the magnetic head element is formed during sputtering. The magnetic field is applied through a magnet holder in which a magnet is combined with a holding unit that holds the wafer W. The present inventor has discovered that a plating base layer having excellent magnetic anisotropy can be formed by applying a magnetic field in parallel with the orientation flat, as shown in Examples described later. As a result, the shield layers 139 and 142 suppress variations in magnetic characteristics among products and have high stability against heat and external magnetic fields.

  Next, a shield layer is formed by electrolytic plating while applying a magnetic field in a direction parallel to the orientation flat OF shown in FIG. 3 (step 1004). As a result, a plated layer having magnetic anisotropy can be formed. Next, a magnetic field is applied to the wafer W at room temperature while applying a magnetic field in a direction perpendicular to the orientation flat OF (ρ-H) (step 1006). Step 1006 is a magnetic property test, in which a magnetic field is applied in a direction perpendicular to the original direction. Thereafter, the wafer W is magnetized while applying a magnetic field in a direction parallel to the orientation flat OF (step 1008). Thereafter, in order to confirm the magnetic characteristics, the wafer W is magnetized while applying a magnetic field in a direction perpendicular to the orientation flat OF (step 1010). Thereafter, the wafer W is heat-treated while applying a magnetic field in a direction parallel to the orientation flat OF (step 1012).

  Next, resist coating, alignment, and development are performed (step 1014), and then heat treatment (hard baking) in the magnetic field of the wafer W is performed (step 1016). Thereafter, sputtering, resist coating, alignment, and development are performed (step 1018), and then the wafer W is subjected to heat treatment (hard baking) while applying a magnetic field in a direction parallel to the orientation flat OF (step 1020). Next, sputtering, resist coating, alignment, and development are performed (step 1022), and then the wafer W is subjected to heat treatment (hard baking) while applying a magnetic field in a direction parallel to the orientation flat OF (step 1024).

  Next, resist coating, alignment, and development are performed (step 1026), and then the wafer W is subjected to heat treatment (hard baking) while applying a magnetic field in a direction parallel to the orientation flat OF (step 1028). Next, resist coating is performed (step 1030). Next, a magnetic field is applied to the wafer W at room temperature while applying a magnetic field in a direction perpendicular to the orientation flat OF for a magnetic property test (ρ-H) (step 1032). Thereafter, the wafer W is heat-treated while applying a magnetic field in a direction parallel to the orientation flat OF (step 1034). Thereafter, sorting and shipment are performed (step 1034).

  Steps 1006, 1010, and 1032 are steps in which a magnetic field is applied to the wafer W in a direction different from the direction of the magnetic field at the time of sputtering, and there is a concern about the deterioration of the shield characteristics. Step 1014 is a film forming process for each layer of the inductive head element 130. Steps 1012 and 1034 are newly added processes. Steps 1016, 1020, 1024, and 1028 are heat treatment steps in which the conventional magnetic field heat treatment step in which deterioration of shield characteristics is a concern is performed in a magnetic field.

  As described above, in this embodiment, the magnetic field heat treatment step (steps 1012, 1016, 1020, 1024, 1028, and 1034) for heat-treating the wafer W in the magnetic field in the same direction as the magnetic field direction at the time of sputtering in step 1002. Have The heat treatment at that time is preferably performed at the temperature of normal heat treatment or higher (for example, 220 ° C. or higher). This is because the “normal heat treatment temperature” is the above-described hard bake temperature conventionally performed in the absence of a magnetic field in this embodiment, and the hard bake requires this temperature. Magnetic domain control is facilitated by heating. By performing the heat treatment, which has conventionally been no magnetic field, with a magnetic field and adjusting the direction of the magnetic field to the orientation flat OF of the wafer W, it is possible to prevent the magnetic characteristics of the shield layer from being deteriorated due to the heat treatment.

  In this embodiment, the magnetic field heat treatment step 1012 is performed once after the room temperature magnetic field application steps 1006 and 1010 are executed, but may be executed once after each of the room temperature magnetic field application steps 1006 and 1010. In this embodiment, the magnetic field heat treatment steps 1012 and 1034 are performed on the room temperature magnetic field application steps 1006, 1010, and 1032. However, the magnetic field heat treatment step may be only step 1034. That is, it is sufficient to execute the room temperature magnetic field application step at least once for a plurality of room temperature magnetic field application steps. In this case, as described above, it is possible to recover from the deterioration of the magnetic characteristics by setting the temperature to be higher than the temperature of the normal heat treatment or making the heat treatment time longer than the time of the normal heat treatment.

  Hereinafter, a modification of the manufacturing method shown in FIG. 2 will be described with reference to FIG. Here, FIG. 4 is a flowchart of a modification of the manufacturing method shown in FIG. 4, the same steps as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In this embodiment, steps 1016, 1020, 1024, and 1028 shown in FIG. 2 are left as in the conventional magneticless heat treatment (hard baking) process (that is, steps 1040, 1044, 1048, and 1052), and then a magnetic field is applied. A heat treatment process (that is, steps 1042, 1046, 1050, and 1054) is added. The heat treatment at that time is preferably performed at the temperature of normal heat treatment or higher (for example, 220 ° C. or higher). In the present embodiment, “normal heat treatment temperature” is the temperature of the above-described magnetic field heat treatment step (that is, steps 1040, 1044, 1048, and 1052). This is because the same or higher temperature is effective in recovering from the magnetic properties deteriorated by the magnetic field heat treatment process. Further, by matching the direction of the magnetic field in the magnetic field heat treatment step with the orientation flat OF of the wafer W, it is possible to prevent the deterioration of the magnetic properties of the shield layer during the heat treatment.

  In the present embodiment, the magnetic field heat treatment step is performed once after the magnetic field heat treatment step is performed. However, it is sufficient that the magnetic field heat treatment step is performed at least once for a plurality of magnetic field heat treatment steps. Therefore, only step 1054 may be provided. In this case, as described above, it is possible to recover from the deterioration of the magnetic characteristics by setting the temperature to be higher than the temperature of the normal heat treatment or making the heat treatment time longer than the time of the normal heat treatment.

In accordance with the manufacturing method of the present embodiment, after sputtering the plating base layer in a state where a magnetic field is applied in parallel to the orientation flat OF in the two magnetic domains (ideal magnetic domains), the three magnetic domains, and the abnormal magnetic domain, the magnetic field heat treatment is performed after the heat treatment in the magnetic field. After that, it was observed after the re-magnetic field heat treatment. That is, these correspond to the observations after the respective steps 1002, 1012, 1040, and 1042 shown in FIG. 6B. In general, {100%-(the ratio of two magnetic domains (%)) + (the ratio of three magnetic domains (%))} = (the ratio of abnormal magnetic domains (%)), but there are four or more magnetic domains. . As shown in FIG. 7, it means a state in which there are two parallel magnetic domain portions 2a and 2b in the longitudinal direction in the return magnetic domain. On the other hand, the three magnetic domains mean a state where there are three. The abnormal magnetic domain is a magnetic domain in which the magnetic domain portions 2a and 2b parallel in the longitudinal direction are not parallel to the orientation flat OF but inclined. The results are shown in FIGS. 5A and 5B. It is understood that the abnormal magnetic domain is 0% at each stage. Further, it is understood that the two magnetic domains which are ideal magnetic domains are improved by the heat treatment in the magnetic field and deteriorate after the magnetic field heat treatment but recover to 97% after the re-magnetic field heat treatment.
(Comparative example)
According to a conventional manufacturing method, two magnetic domains (ideal magnetic domains), three magnetic domains, and anomalous magnetic domains were observed after sputtering, after heat treatment in a magnetic field, after non-magnetic heat treatment, and after re-magnetic field heat treatment. In the comparative example, sputtering was performed without a magnetic field, and a heat treatment in a magnetic field and a re-magnetic field heat treatment that were not originally present in a conventional manufacturing method were added. The results are shown in FIGS. 6A and 6B. It is understood that the abnormal magnetic domains are 100%, 58%, 44%, and 61% at each stage. That is, it is understood that when the sputtering is performed without a magnetic field, the abnormal magnetic domain is not completely removed even if a magnetic field heat treatment is performed thereafter.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

  The present invention further discloses the following matters.

(Supplementary Note 1) A method of manufacturing a magnetic head element having a soft magnetic layer,
Forming a plating base layer of the soft magnetic layer by sputtering;
Applying a magnetic field in a direction parallel to the orientation flat of the wafer on which the head element is formed during the film forming step. (1)
(Additional remark 2) The said soft-magnetic layer is a shield layer which shields an external magnetic field, The method of Additional remark 1 characterized by the above-mentioned.

(Appendix 3) Forming the soft magnetic layer by electrolytic plating using the plating base layer;
The method according to claim 1, further comprising: applying a magnetic field in the direction during the electrolytic plating film forming step.

(Supplementary note 4) The method according to supplementary note 1, further comprising a magnetic field heat treatment step of heat treating the wafer in a magnetic field in the same direction as the direction. (2)
(Supplementary Note 5) The method further includes a step of applying a magnetic field to the wafer at a room temperature in a direction different from the direction,
The method according to appendix 4, wherein the magnetic field heat treatment step is performed after the room temperature magnetic field application step. (3)
(Supplementary note 6) The method according to supplementary note 5, wherein the magnetic field heat treatment step is performed at least once after the room temperature magnetic field application step is performed or after the room temperature magnetic field application step is performed a plurality of times.

(Additional remark 7) It further has the step which heat-processes the said wafer by a magnetic field,
The method according to appendix 4, wherein the magnetic field heat treatment step is performed after the magnetic field heat treatment step. (4)
(Supplementary note 8) The method according to supplementary note 7, wherein the magnetic field heat treatment step is executed at least once after the execution of the magnetic field heat treatment step or after the magnetic field heat treatment step is performed a plurality of times. (5)
(Supplementary note 9) The method according to supplementary note 7, wherein the temperature of the magnetic field heat treatment step is equal to or higher than the temperature of the magnetic field heat treatment step.

  (Supplementary note 10) The method according to supplementary note 1, wherein the magnetic head element is a combined head element of a write head element and a read head element.

It is an expanded sectional view which shows the structure of a magnetic head element. It is an expanded sectional view which shows the structure of another magnetic head element. 3 is a flowchart for explaining a method of manufacturing a magnetic head element according to an embodiment of the present invention. It is a top view for demonstrating the application direction of a magnetic field. It is a flowchart as a modification of FIG. It is a table | surface which shows the magnetic domain state of the magnetic head element manufactured by the manufacturing method of a present Example. It is a graph of FIG. 5A. It is a table | surface which shows the magnetic domain state of the magnetic head element manufactured by the conventional manufacturing method. It is a graph of FIG. 6A. It is a schematic plan view of a reflux magnetic domain.

Explanation of symbols

139, 142 Shield layer 139a, 142a Plating base layer

Claims (5)

A method of manufacturing a magnetic head element having a soft magnetic layer,
Forming a plating base layer of the soft magnetic layer by sputtering;
Applying a magnetic field in a direction parallel to the orientation flat of the wafer on which the head element is formed during the film forming step.   2. The method according to claim 1, further comprising a magnetic field heat treatment step of heat-treating the wafer in a magnetic field in the same direction as the direction. Applying a magnetic field to the wafer in a direction different from the direction at room temperature;
The method according to claim 2, wherein the magnetic field heat treatment step is performed after the room temperature magnetic field application step. Further comprising the step of heat-treating the wafer without a magnetic field;
The method according to claim 2, wherein the magnetic field heat treatment step is performed after the magnetic field heat treatment step.   5. The method according to claim 4, wherein the magnetic field heat treatment step is performed at least once after the execution of the magnetic field heat treatment step or after the magnetic field heat treatment step is performed a plurality of times.