Method for fixing a metal member

Abstract

To provide a metal member fixing method which can suppress occurrence of a resin residue.SOLUTION: A metal member fixing method fixes a metal member 3 onto a substrate 2 by a fixing resin 4. The method mounts a metal member 3 at a predetermined position of a substrate 2, coats a negative type photosensitive resist diluted with a diluent solvent onto the substrate 2 so as to cover at least a part of the metal member 3, exposing, heating and developing a part of the photosensitive resist and thereby forms a fixing resin 4 at a predetermined position. The photosensitive resist is composed of SU-8. The diluent solvent is composed of PGMEA.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for fixing a metal member.

Background Art

[0002] For example, when manufacturing an MI sensor, there is a step of fixing a magnetic wire on a substrate. In such a case, a technique of forming a guide post at a predetermined position on the substrate for positioning the magnetic wire on the substrate is disclosed in Patent Document 1. It is described in the same document that photolithography is used for forming the guide post, and the magnetic wire is arranged on the substrate along the formed guide post.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the inventors have found that the following problems occur when resin is formed to cover the magnetic wire and fix the magnetic wire after the magnetic wire is arranged on the substrate. That is, when trying to fix the magnetic wire to the substrate with a fixing resin formed using photolithography after arranging the magnetic wire on the substrate, resin residues may remain. That is, when attempting to form a fixing resin at a predetermined position by exposing, heating, and developing a negative-type photosensitive resist, an event may occur in which resist residues also remain at positions other than the predetermined position (i.e., unexposed locations).

[0005] The present invention has been made in view of such problems, and aims to provide a method for fixing a metal member that can suppress the generation of resin residues. [Means for solving the problem]

[0006] One aspect of the present invention is a method for manufacturing a semiconductor device comprising: At a plurality of locations spaced apart from each other A method for fixing a metal member, comprising the steps of: placing the metal member at a predetermined position on the substrate; A negative photosensitive resist diluted with a dilution solvent is applied onto the substrate so as to cover at least a portion of the metal member; A part of the photosensitive resist is exposed to light, heated, and developed, So as to cover a plurality of locations spaced apart from each other in the metal member The above fixing resin is formed in a predetermined position. And expose portions of the metal member other than the plurality of locations from the fixing resin , The photosensitive resist is made of SU-8, The dilution solvent is composed of PGMEA. The present invention relates to a method for fixing a metal member. Effect of the Invention

[0007] In the metal member fixing method, SU-8 is used as the photosensitive resist and PGMEA is used as the dilution solvent, which can suppress the generation of resin residue when the fixing resin is formed.

[0008] As described above, according to the present invention, a method for fixing a metal member that can suppress the generation of resin residue can be provided. [Brief description of the drawings]

[0009]

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Figure 5

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Figure 9

Mode for Carrying Out the Invention

[0010] The above metal member can be an amorphous wire. In this case, when fixing the amorphous wire on the substrate, the generation of resin residues can be suppressed.

[0011] Also, the above metal member can be the magnetoresistive element of a magneto-impedance sensor element (hereinafter, also appropriately referred to as an MI element). In this case, a high-quality magneto-impedance sensor element can be easily manufactured.

[0012] (Embodiment 1) An embodiment of the metal member fixing method will be described with reference to FIGS. 1 to 6. The metal member fixing method of this embodiment is a metal member fixing method in which, as shown in FIGS. 1 to 5, the metal member 3 is fixed with a fixing resin 4 on the substrate 2 using photolithography.

[0013] That is, in the method for fixing a metal member according to this embodiment, the metal member 3 is placed at a predetermined position on the substrate 2 (see FIGS. 1 and 2). Then, a negative-type photosensitive resist 40 diluted with a diluting solvent is applied onto the substrate 2 so as to cover at least a part of the metal member 3 (see FIG. 3). Then, a part of the photosensitive resist 40 is exposed, heated, and developed to form a fixing resin 4 at a predetermined position (see FIGS. 4 and 5).

[0014] The photosensitive resist 40 is made of SU-8. The diluting solvent is made of PGMEA. SU-8 is a negative-type photoresist mainly composed of an epoxy resin and containing cyclopentanone as a solvent. PGMEA is the abbreviation of propyleneglycol monomethyl ether acetate. Also, PGMEA is generally used as a developer for SU-8.

[0015] In this embodiment, the metal member 3 is an amorphous wire. Also, the metal member 3 is a magneto-sensitive body of an MI element. In this embodiment, the metal member 3 will be described as the magneto-sensitive body 3. The method for fixing a metal member according to this embodiment is carried out in a part of the process of the method for manufacturing an MI element.

[0016] The MI element 1 has, for example, as shown in FIG. 6, a magneto-sensitive body 3 and a detection coil 11 wound around it. The magneto-sensitive body 3 and the detection coil 11 are arranged on the surface of the substrate 2. A part 111 of the detection coil 11 is formed by a conductor pattern formed on the surface of the substrate 2. Also, the lead-out wiring 121 connected to the detection coil 11 and the lead-out wiring 122 connected to the magneto-sensitive body 3 are also pattern-formed on the surface of the substrate 2. Note that the other part 112 of the detection coil 11 is formed on the outer peripheral side of the magneto-sensitive body 3 via an insulating layer (not shown) after the magneto-sensitive body 3 is arranged.

[0017] An example of the method for manufacturing such an MI element 1 will be described below. On the surface of a substrate 2 made of a non-magnetic material such as alumina or semiconductor silicon, a conductor pattern is appropriately formed in advance. Then, a magnetosensitive body 3 is placed at a predetermined position on the surface of the substrate 2. For positioning this magnetosensitive body 3, as shown in FIG. 1, a guide pattern 5 is formed on the substrate 2 in advance. This guide pattern 5 can be formed, for example, by protruding an insulator such as resin on the substrate 2.

[0018] In this embodiment, as shown in FIG. 2, the magnetosensitive body 3 is arranged in a state where the linear magnetosensitive body 3 is sandwiched between the guide patterns 5 arranged close to each other. Next, as shown in FIG. 3, a photosensitive resist 40 is applied onto the substrate 2. At this time, the photosensitive resist 40 is applied over substantially the entire substrate 2 so as to cover the magnetosensitive body 3. Also, the photosensitive resist 40 is made of SU-8, a negative-type photoresist. And this photosensitive resist 40 is applied to the substrate 2 in a state diluted with a diluting solvent. As this diluting solvent, PGMEA is used.

[0019] Note that SU-8, which is the photosensitive resist 40, is a liquid resist in a state where an epoxy resin is dissolved in a solvent composed of cyclopentanone. And by diluting this photosensitive resist 40 with a diluting solvent composed of PGMEA, it is adjusted to an appropriate viscosity. For example, the mixing ratio of SU-8 and PGMEA can be about 1:1 to 1:5. Then, the viscosity-adjusted photosensitive resist 40 is applied to the substrate 2.

[0020] The substrate 2 coated with the photosensitive resist 40 is pre-baked. At this time, the diluting solvent volatilizes. Then, as shown in FIG. 4, a photomask 61 is placed on the substrate 2, and the photosensitive resist 40 at a predetermined position is exposed to ultraviolet light. Next, the photosensitive resist 40 is heated. That is, post-exposure baking (PEB) is performed. Thereby, the chain polymers of SU-8 of the exposed photosensitive resist 40 are crosslinked.

[0021] Next, the photosensitive resist 40 is developed with a developer. As a result, the unexposed portions in the photosensitive resist 40 are dissolved and removed. Consequently, as shown in FIG. 5, the fixing resin 4 is formed at a desired position. Then, the magneto-sensitive member 3 is fixed onto the substrate 2 by this fixing resin 4. The developer used in this developing process is composed of PGMEA.

[0022] Note that, after the magneto-sensitive member 3 is fixed to the substrate 2, the MI element 1 is obtained by performing a part of etching of the magneto-sensitive member 3, formation of an insulating layer, electrical bonding between the magneto-sensitive member 3 and a lead-out wiring (refer to reference numeral 122 in FIG. 6), formation of a conductor pattern of a part of the detection coil 11 (refer to reference numeral 112 in FIG. 6), and the like.

[0023] Next, the operation and effect of this embodiment will be described. In the method for fixing a metal member of this embodiment, SU-8 is used as the photosensitive resist 40, and PGMEA is used as the diluting solvent. Thereby, generation of resin residues when forming the fixing resin 4 using photolithography can be suppressed.

[0024] The inventors of the present application have found a problem that resin residues may occur when cyclopentanone is used as a diluting solvent of the photosensitive resist 40 when applying SU-8, which is the photosensitive resist 40, to the substrate 2 (refer to Experimental Example 1 and FIG. 7 described later). Cyclopentanone is contained as its solvent in SU-8. Therefore, a means of using cyclopentanone as a diluting solvent has been adopted for adjusting the viscosity of SU-8.

[0025] However, as described above, when the fixing resin 4 for fixing the magneto-sensitive body 3 on the substrate 2 was formed, resin residues sometimes remained. As a cause of this, it is considered that SU-8 may partially cause a cross-linking reaction even in the unexposed portion. As factors of the cross-linking reaction, ultraviolet rays, heat, and acid are considered. Here, when SU-8 was developed without exposure, resin residues similar to the above were observed, so it is considered that ultraviolet rays are not the cause. Also, since the cross-linking reaction is a mechanism that is promoted by heat after giving some trigger, it is unlikely that heat is the main factor. Therefore, as the remaining factor, acid is considered a strong candidate.

[0026] That is, as a hypothesis, it is considered that acid adheres to the surface of the magneto-sensitive body 3 before being placed on the substrate 2. As an experiment to support this hypothesis, when the photosensitive resist 40 was exposed, heated, and developed without placing the magneto-sensitive body 3, no residue remained. Therefore, this hypothesis is strong. And, for example, in the processing step of the magneto-sensitive body 3, it is conceivable that acidic chemicals or the like adhere to the surface of the magneto-sensitive body 3. It is considered that when this acid touches the photosensitive resist 40, the cross-linking reaction proceeds slightly, and as a result, even in the unexposed portion, it remains as a residue after development.

[0027] As a countermeasure, it is conceivable to strengthen the cleaning of the magneto-sensitive body 3 before placing the magneto-sensitive body 3 on the substrate 2 so that no acid remains on its surface. However, it is difficult to completely remove the acid, and considering productivity, it is not realistic.

[0028] Therefore, the inventors of the present application considered the possibility that the cross-linking reaction of the photosensitive resist 40 occurs before exposure, and studied changing the dilution solvent used at the time of coating from cyclopentanone to PGMEA. As described above, PGMEA is used as a developer for SU-8. The inventors considered that PGMEA used as this developer may have an effect of inhibiting even a slight cross-linking reaction of SU-8 caused by a slight amount of acid.

[0029] Therefore, actually, as described above, when PGMEA was used as the diluting solvent, it was confirmed that no resin residue remained after development (see Experimental Example 1 and FIG. 8 described later). Thus, by using PGMEA as the diluting solvent for the photosensitive resist 40, the generation of resin residues can be suppressed.

[0030] Generally, as a diluent for a photosensitive resist, a chemical solution that does not affect the crosslinking reaction is used. As described above, the inventors of the present application used PGMEA, which has an effect of suppressing the crosslinking reaction of SU-8, as a diluting solvent to solve the above problems.

[0031] As described above, according to this embodiment, it is possible to provide a method for fixing a metal member that can suppress the generation of resin residues.

[0032] (Reference Embodiment) This embodiment is a form in which 4-hydroxy-4-methyl-2-pentanone or ethyl lactate is used instead of PGMEA as the diluting solvent for SU-8. 4-Hydroxy-4-methyl-2-pentanone and ethyl lactate are generally used as developers for SU-8. Therefore, by using these as the diluting solvents for SU-8, an effect of suppressing the generation of resin residues can be expected, similar to Embodiment 1. Other aspects are the same as those of Embodiment 1.

[0033] (Experimental Example 1) This example is an example in which, as shown in FIGS. 7 and 8, the effect of suppressing the generation of resin residues by the method for fixing a metal member shown in Embodiment 1 above was confirmed. That is, the appearance of the obtained MI elements was compared between the case where cyclopentanone was used as the diluting solvent for the photosensitive resist 40 and the case where PGMEA was used.

[0034] The MI element obtained when the diluting solvent is cyclopentanone is designated as Sample 1. The MI element obtained when the diluting solvent is PGMEA is designated as Sample 2. The manufacturing method of Sample 2 is the same as that of Embodiment 1. The manufacturing of Sample 1 is also the same as that of Embodiment 1, except that cyclopentanone is used as the diluting solvent for the photosensitive resist SU-8. Also, in both Sample 1 and Sample 2, the mixing ratio of SU-8 and the diluting solvent was set to 1:5. Note that a plurality of each of Sample 1 and Sample 2 were manufactured.

[0035] The appearances of those among the obtained Sample 1 in which residues were particularly prominent are shown in FIGS. 7(a) and (b). Also, the appearance of the obtained Sample 2 is shown in FIG. 8. As shown in FIGS. 7(a) and (b), in Sample 1, there were some in which resin residues had occurred. In Sample 1, it particularly appears that the residues are spreading from the magnetoresistive element. On the other hand, as shown in FIG. 8, in Sample 2, no resin residues were particularly observed.

[0036] From the results of this example, it was confirmed that by using PGMEA as the diluting solvent for the photosensitive resist 40, the generation of resin residues can be suppressed.

[0037] (Experimental Example 2) This example is an example in which, as shown in FIG. 9, it was confirmed that there is no contradiction due to using PGMEA as the diluting solvent for SU-8.

[0038] That is, the chemical resistance of the fixed resin 4 formed by the method shown in Embodiment 1 was confirmed. As described above, PGMEA is generally used as a developer for SU-8 and is considered to have an effect of suppressing the crosslinking of SU-8. Therefore, as a contradiction when using PGMEA as the diluting solvent for SU-8, the chemical resistance of the fixed resin after development is a concern. Thus, in this example, a test was conducted to confirm that there is no problem with the chemical resistance of the fixed resin.

[0039] Here, the resistance of the fixing resin 4 to chemicals that may come into contact during the manufacturing process of the MI element was confirmed. In the processes after forming the fixing resin 4, for example, there are a process of etching a part of the magnetoresistive element 3, a process of forming a connection pattern for connecting both ends of the magnetoresistive element 3 to the conductor pattern on the substrate 2, and the like. In each process, an etching solution, a resist stripper, etc. are used respectively. In the former process, these chemicals may come into contact with the fixing resin 4, and in the latter process, these chemicals may indirectly come into contact with the fixing resin 4.

[0040] Specifically, in the former process, hydrogen peroxide is used as the etching solution, Clean Strip HP-2 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is used as the resist stripper, and ethanol is used as the rinse after stripping. In the latter process, sulfuric acid is used as the etching solution, PGMEA is used as the resist developer, and acetone is used as the resist stripper.

[0041] Therefore, the resistance of the fixing resin to these chemicals, namely PGMEA, ethanol, sulfuric acid, hydrogen peroxide, acetone, and Clean Strip HP-2, was evaluated by tests.

[0042] Specifically, after applying SU-8 diluted with PGMEA onto the substrate, through exposure, PEB, and development, a resin pattern (test pattern) corresponding to the fixing resin 4 shown in Embodiment 1 was formed. However, since this test pattern is for the chemical resistance test, it was formed on the substrate without arranging the magnetoresistive element or the like.

[0043] Then, after immersing the formed test patterns in each chemical for a predetermined time, the appearance was observed. The results are shown in FIG. 9. Also, the test conditions are as shown in Table 1 below. These test conditions were set based on the conditions assumed in the actual manufacturing process of the MI element. Table 1 also shows the evaluation results. The evaluation was performed based on whether swelling, peeling, dissolution, etc. occurred in the test patterns after the test. Also, in Table 1 and FIG. 9, "OK" indicates that problems such as swelling, peeling, and dissolution did not occur.

[0044]

Table 1

[0045] As shown in FIG. 9 and Table 1, it was confirmed that in any of the samples, there was no occurrence of swelling, peeling, dissolution, etc., and that all of them had sufficient resistance to any chemical. In fact, even after manufacturing the MI element by the method shown in Embodiment 1 (that is, after preparing Sample 2 in Experimental Example 1), in particular, swelling, peeling, dissolution, etc. of the fixing resin 4 did not occur, and no problems such as the magnetic body 3 coming off occurred.

[0046] The present invention is not limited to the above embodiments, and can be applied to various embodiments without departing from the gist thereof.

Explanation of Reference Numerals

[0047] 1 Magneto-Impedance Sensor Element 2 Substrate 3 Metal Member (Magnetic Body) 4 Fixing Resin

Claims

1. A method for fixing a metal member, which fixes a plurality of separated positions on the metal member to a substrate with a fixing resin, comprising: placing the metal member at a predetermined position on the substrate; applying a negative photosensitive resist diluted with a diluting solvent onto the substrate so as to cover at least a part of the metal member; forming the fixing resin at a predetermined position so as to cover a plurality of separated positions on the metal member by exposing, heating, and developing a part of the photosensitive resist, and exposing parts of the metal member other than the plurality of positions from the fixing resin; the photosensitive resist is made of SU-8; the diluting solvent is made of PGMEA; A method for fixing a metal member.

2. The method for fixing a metal member according to claim 1, wherein the metal member is an amorphous wire.

3. The method for fixing a metal member according to claim 2, wherein the metal member is a magnetoresistive element of a magneto-impedance sensor.

4. The method for fixing a metal member according to claim 1 or 2, wherein the photosensitive resist is applied onto the substrate so as to cover the entire metal member.

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