JP7203400B1 - Method for manufacturing GSR element - Google Patents

Abstract

Kind Code: A1 When a GSR element is directly formed on an integrated circuit board (ASIC), it is essential to form an inverted trapezoidal groove. Elevated alignment marks must be formed at the same time as the grooves. Inverted trapezoidal grooves are made possible by applying a positive resist-type photosensitive resin to the entire ASIC substrate, exposing, developing, and then performing a curing heat treatment, and simultaneously forming grooves and alignment marks on the photosensitive resin film. do. Further, by forming a metal film and forming a plurality of highly visible alignment marks and a lower coil, it is possible to improve the alignment accuracy. [Selection drawing] Fig. 6

Description

The present invention relates to a method of manufacturing a GSR element in which a magnetic field detection element and an application specific integrated circuit (hereinafter referred to as ASIC) are directly bonded.

High-sensitivity magnetic sensors include Hall sensors, GMR sensors, TMR sensors, high-frequency carrier sensors, FG sensors, MI sensors, GSR sensors, and the like. Among these sensors, Hall sensors, GMR sensors, TMR sensors, and carrier sensors have been made smaller and thinner by integrating elements with ASICs, but improvement in detection sensitivity is a problem.
On the other hand, although the FG sensor, MI sensor, and GSR sensor have high sensitivity, the element and the ASIC are separately arranged and joined by wire bonding, and thinning and miniaturization of the sensor is a problem.

In order to solve this problem, the present inventors worked on the development of technology to directly form the GSR element on the surface of the ASIC and bond it to the ASIC with a bare hole. Patent document 1).
In Patent Document 1, an insulating resist is applied on the ASIC surface, grooves for arranging magnetic wires are formed there, and a GSR element consisting of a magnetic wire and a detection coil and electrodes surrounding the magnetic wire is formed on the ASIC surface. A thin integrally formed high sensitivity magnetic sensor is disclosed.
However, details of the technology for the manufacturing method have not been disclosed. Furthermore, the manufacturing technology has been continuously improved up to the present.

On the other hand, in order to increase the sensitivity of the sensor, it is necessary to form a fine pitch coil and increase the number of turns of the coil. However, as the coil pitch becomes finer, it is required to align the position of the ASIC substrate (hereinafter referred to as substrate) and the mask with higher accuracy. In order to achieve such accuracy, highly visible alignment marks must be formed on the substrate with high accuracy.

In general, since alignment marks are formed on a SiO ₂ film made on a flat portion, there is no problem with visibility. Alignment mark forming methods are disclosed in Patent Document 2, Patent Document 3, and Patent Document 4, etc., but none of these methods form an alignment mark on a photosensitive resin. Another issue is the study of technology for forming highly visible alignment marks on photosensitive resin.

JP 2019-191016 A JP 2006-229132 A JP 2009-004793 A Japanese Patent No. 2016776 Japanese Patent No. 5747294 Japanese Patent No. 6438616

When forming a GSR element on a Si substrate, the Si substrate is processed to directly form grooves. A thermal oxide film with a thickness of about 100 nm is usually formed on a Si substrate. First, in order to remove this thermal oxide film, the entire substrate is coated with a resist, exposed using a line-shaped mask, developed, and the thermal oxide film is removed by RIE (Reactive Ion Etching) to expose the Si surface. Let

Next, it is immersed in an alkaline etchant (for example, potassium hydroxide solution). Since the Si substrate has a different etching rate depending on its orientation, by using a Si substrate with a <100> crystal orientation, it is possible to form the inverted trapezoidal groove 13 as shown in FIG. 1 by anisotropic etching.
In the GSR element, a magnetic wire is inserted in an inverted trapezoidal groove, a lower coil is formed along the groove, an upper coil is formed on the upper surface of the wire, and the two are connected to form a coil. By forming the coil using the inverted trapezoidal groove, the coil can be formed very close to the wire.

However, when the GSR element is integrally formed on the ASIC substrate, it is impossible to form grooves on the ASIC substrate because circuit wiring exists on the surface of the ASIC substrate.
Therefore, an insulating film 23 such as SiO2 is formed on the ASIC substrate 21, and a groove 24 is formed by RIE (Reactive Ion Etching). It was found that the shape groove could not be formed.

As a photosensitive resin that is generally left as a structure, an epoxy-based negative type resist (hereinafter referred to as a negative resist) is known. A feature of the negative resist is that the edge shape after patterning is sharp, and as shown in FIG. 3, even after the curing heat treatment for leaving as a structure, the groove 34 becomes a rectangular parallelepiped shape and the shape does not change.
Therefore, it is difficult to form an inverted trapezoidal groove using a negative resist.

On the other hand, in order to increase the sensitivity of the sensor, it is necessary to reduce the coil pitch to 10 μm or less and increase the number of turns of the coil. However, as the coil pitch becomes finer, it is required to align the position of the ASIC board (hereinafter referred to as the board) and the positions of the plurality of masks with higher accuracy. In order to achieve such precision, an alignment mark with high visibility is formed at the same time as the grooves are formed, thereby improving the alignment precision.

In the process of directly bonding a magnetic field detection element and an application specific integrated circuit (hereinafter referred to as ASIC) by photolithography, the present invention forms a film of photosensitive resin on an ASIC substrate and arranges magnetic wires thereon. Developed a method of simultaneously forming an inverted trapezoidal groove and a high-contrast, i.e., highly visible, alignment mark, directly forming a GSR element on an ASIC substrate, and bonding the GSR element and ASIC bare-bonded together. It is something to do.

The present inventors paid attention to the characteristics of a positive resist type photosensitive resin in order to form an inverted trapezoidal groove in a resin film. When fabricating a resin structure, a negative resist type photosensitive resin that does not change its shape after curing is generally used, but this cannot form an inverted trapezoidal groove. Therefore, I decided to research positive resist resin.
After coating the entire ASIC substrate with a positive resist-based photosensitive resin, exposing through a mask material, and developing, a large number of rectangular parallelepiped grooves 414 are formed on the entire surface of the substrate and subjected to a curing heat treatment to obtain the shape shown in FIG. It has been found that the groove 424 can be changed into an inverted trapezoidal groove 424 .
Furthermore, the groove and the alignment mark portion are simultaneously formed on the film of the photosensitive resin. It was confirmed that the cured positive-resist type photosensitive resin slightly changed its shape, but had good chemical resistance and could be used as a structure.

That is, the entire surface of the ASIC substrate is coated with a positive resist resin film, exposed through a mask material, and then developed, thereby simultaneously forming grooves and recesses for alignment marks. At this time, the shape of the groove is a rectangular parallelepiped. At this time, the pattern of the opening of the electrode portion of the ASIC substrate is also exposed and developed at the same time to remove the resin film on the electrode portion.
Next, a curing heat treatment is performed. When the curing heat treatment is performed, the groove changes from a rectangular parallelepiped shape to an inverted trapezoid shape due to the stress generated during the heat treatment. This is the effect of adopting the positive resist type resin film instead of the SiO2 film or the negative resist type resin film. The disadvantage is that the shape of the recessed portion of the alignment mark is also an inverted trapezoid, which reduces the visibility of the mark. This problem is solved by etching the SiO2 on the surface of the ASIC by RIE using the above-mentioned inverted trapezoidal alignment mark portion itself as a mask after protecting the portion other than the alignment mark portion with a resist, thereby sharpening the edge of the etched alignment mark. I found that I can solve it by making it.

Next, a negative resist resin coating is applied, exposed and developed to leave the resin coating only in the grooves, and a curing heat treatment is performed to form an R shape at the bottom of the grooves.
Then, a metal film is formed on the entire surface of the ASIC substrate on which the inverted trapezoidal grooves and the alignment mark recesses are formed. As a result, the recesses for the alignment marks are covered with the metal film, and this film functions as a reflective film, so it has been found that the visibility of the alignment marks can be further improved. This metal film is formed along the inverted trapezoidal groove, and is coated with a resist, exposed using the alignment marks, and developed to form the lower coil along the inverted trapezoidal groove. Patterns can be formed. After plating, the resist is removed and the metal film other than the coil portion and electrode portion is wetted to form a lower coil with a thickness of 0.2 to 1.0 μm in the groove portion. An R portion is formed at the bottom of the groove, and even fine wiring with a line width of 0.5 to 2 μm can form the lower coil without disconnection.

Next, a magnetic wire is placed in the groove in which the lower coil is formed by applying a tension of 50 to 100 kg/mm ² . At this time, the magnetic wire is fixed to the jig with an adhesive, tape, or the like in order to maintain its tension. After that, a negative resist resin film is applied, and heat treatment is performed at 90° C. for temporary fixing of the magnetic wire. Then, the magnetic wires are fixed inside the grooves by performing exposure, baking, development, and curing heat treatment, and the wires are heat-treated while maintaining tension, so that the GSR characteristics can be improved. Here, the temperature of the curing heat treatment is 250-350.degree.

A portion of the insulating glass covering the magnetic wire is removed by CF ₄ -RIE in order to provide wire terminals (both ends of the magnetic wire) to the magnetic wire fixed inside the groove.

Next, a positive resist-based resin film is applied to the upper portion of the magnetic wire, and a curing heat treatment is performed. Thereby, the step between the groove and the magnetic wire can be eliminated.

Then, a metal film is formed, resist is applied, exposed and developed to form an upper coil along the wire. At this time, by using the alignment marks, the alignment accuracy is improved, and the upper coil can be formed without deviation from the lower coil even with a fine coil pitch.
After plating, the resist is removed, and the metal film other than the coil portion and the electrode portion is wetted to form an upper coil with a thickness of 0.2 to 1.0 μm in the groove portion.

As for the technique of forming an element by aligning magnetic wires in an inverted trapezoidal groove on a substrate, the inventors of the present invention disclosed Patent Document 5 (Japanese Patent No. 5747294) and Patent Document 6 (Japanese Patent No. 6438616). ), etc., have been disclosed through presentations at international academic conferences, etc., and the technology for forming elements on a substrate has been disclosed in a patent publication by Aichi Steel Co., Ltd., and has become a well-known technology.
Therefore, the description of the disclosed technology and the well-known technology is simplified in the present invention.

By simultaneously forming an inverted trapezoidal groove and a plurality of alignment marks in the positive resist resin film on the ASIC substrate in this way, the accuracy of aligning a plurality of masks can be improved, and a fine coil of about 1 μm to 10 μm can be formed. Formation of pitch becomes possible.

According to the present invention, it is possible to simultaneously form an inverted trapezoidal groove for arranging a magnetic wire and a highly visible alignment mark on a photosensitive resin film without damaging the ASIC substrate. It is possible to integrally form a GSR element having a fine coil pitch of 5 μm or less, or even 3 μm or less.

It is a figure which shows the groove|channel of the inverted trapezoid formed on the Si substrate. FIG. 10 is a diagram showing rectangular parallelepiped grooves formed in a SiO2 film coated on an ASIC substrate; FIG. 10 is a diagram showing rectangular parallelepiped grooves formed by photolithography using a negative type resist coated on an ASIC substrate, followed by curing heat treatment; FIG. 10 shows (a) rectangular parallelepiped grooves after photolithography, and (b) inverted trapezoidal grooves formed by curing the grooves using a positive resist coated on an ASIC substrate. 1 is a cross-sectional view of a GSR element manufactured by the manufacturing method of the present invention; FIG. FIG. 4A is a plan view of a groove forming portion and an alignment mark forming portion on an ASIC substrate of the present invention, and FIG. FIG. 10 is a flow chart (cross-sectional view) for forming a groove forming portion and an alignment mark forming portion using a positive resist on an ASIC substrate of the present invention, showing a rectangular parallelepiped groove after photolithography. FIG. 10 is a flow chart (cross-sectional view) for forming a groove forming portion and an alignment mark forming portion using a positive resist on an ASIC substrate of the present invention, showing an inverted trapezoidal groove formed by curing. FIG. 4 is a cross-sectional view of a lower coil formed in a grooved portion of the present invention, an alignment mark formed by forming a metal film on an alignment portion, and a reflective film;

The manufacturing method of the GSR element is
A magnetic wire, a detection coil having a coil pitch of 10 μm or less consisting of a lower coil and an upper coil surrounding the magnetic wire, and a GSR element consisting of electrodes are directly mounted on a substrate of an application specific integrated circuit (hereinafter referred to as ASIC). In the method of manufacturing
(1) A positive resist type resin film is applied onto the ASIC substrate, exposed and developed to simultaneously form grooves for placing the magnetic wires and a plurality of concave portions for alignment marks in the resin film, followed by curing heat treatment. After curing to form inverted trapezoidal grooves and recesses for alignment marks, a negative resist resin coating is applied, exposed and developed to leave the resin coating only in the inverted trapezoidal grooves, and a curing heat treatment is performed. forming an R shape at the bottom of the groove,
(2) forming an alignment mark with high visibility by forming a metal film and using the metal film as a reflective film for the concave portion of the alignment mark;
(3) forming the lower coil along the surface of the inverted trapezoidal groove using the alignment mark and the metal film covering the inverted trapezoidal groove;
(4) the magnetic wire is placed while tension is applied to the inverted trapezoidal groove in which the lower coil is formed, temporarily fixed with resin, and then fixed by curing heat treatment;
(5) removing the insulating glass covering the wire in the wire electrode portion for joining the wire and the electrode wiring by CF ₄ -RIE;
(6) applying a positive resist-based resin coating to the entire surface of the substrate, exposing and developing to leave the positive resist-based resin coating only in the grooves and the magnetic wire portions, and performing a curing heat treatment to smooth the steps;
(7) forming the upper coil and electrodes;
(8) It is characterized in that an assembly of the GSR elements comprising the magnetic wire, the detection coil and the electrode is separated into individual pieces.

Further, in the above step (4),
The magnetic wire is placed on the lower coil with a tension of 30 to 100 kg/mm ² applied, the magnetic wire is embedded in the groove with resin, and subjected to tension heat treatment at a temperature of 250 to 350° C. It is characterized by fixing the magnetic wire and improving the GSR characteristics at the same time.

A cross-sectional view of the structure of a GSR element manufactured according to the present invention is shown in FIG.
The GSR element 5 of the present invention comprises an ASIC substrate 51, a SiO2 protective film 52 on the ASIC substrate 51, a positive resist 53 coated on the SiO2 protective film 52, and an inverted trapezoidal groove 54 formed in the positive resist 53. , the resin film 50 which is arranged at the groove bottom and forms an R shape at the bottom, the surface of the inverted trapezoidal groove 54 and a part of the upper surface of the positive resist 53, the lower coil 55 which is arranged on the lower coil. a magnetic wire 56, a resin film 58 for fixing the magnetic wire, a positive resist-based resin film 59 for eliminating a step between the magnetic wire 56 and the groove 54, and a magnetic wire 56 formed on the resin film 59 and connected to the lower coil 55. and an upper coil 57 .
The magnetic wire 56 is wound by a detection coil composed of a lower coil 55 and an upper coil 57, and the gap between the detection coil and the magnetic wire is filled with insulating resins 58 and 59. FIG.

A method for manufacturing the GSR element will be described in detail below.
First, referring to FIG. 6, a substrate 60 for forming a GSR element, which is an intermediate step product of the process of the present invention, will be described. (a) is a plan view, and (b) is a cross-sectional view taken along line A1-A2 of (a).
In manufacturing the GSR elements, a plurality of GSR elements are formed on one ASIC substrate. In addition, since the photolithography process is performed multiple times, the alignment marks are composed of multiple pieces. This FIG. 6 will be described by showing only one GSR element.

An intermediate process product of a GSR element forming substrate 60 comprising a groove forming portion 6G comprising an inverted trapezoidal groove 64G and an alignment mark portion 6A comprising an alignment mark concave portion 64A for forming a GSR element on an ASIC substrate 61. formed.
The groove forming portion 6G is composed of a positive resist 63G and an inverted trapezoidal groove 64G. The alignment mark portion 6A has a cross section formed of a positive resist 63A and an alignment mark concave portion 64A at the alignment 6a of a plurality of +marks.

Next, the process will be described with reference to the flow diagrams of FIGS. 7(a)-(b).
a) As shown in FIG. 7(a), a positive resist-based resin film (hereinafter referred to as positive resist) is applied on an ASIC substrate to a thickness of 3 to 10 μm, exposed through a mask material, and developed to form a resin film. A groove 74Ga with a depth of 3 to 10 μm for arranging a magnetic wire with a diameter of 5 to 20 μm and an alignment mark recess 74Aa with a depth of 3 to 10 μm are simultaneously formed to form a rectangular parallelepiped groove 74Ga and an alignment mark recess 74Aa. do.

The thickness of the positive resist 73Ga of 3 to 10 μm corresponds to the depth of the groove 74Ga of 3 to 10 μm, and the groove depth needs to be more than half the diameter of the magnetic wire in order to stably arrange the magnetic wire in the groove. It is preferable that the thickness of the resin coating is equal to or less than the diameter of the magnetic wire. Considering that the magnetic wire has a diameter of 5 μm to 20 μm, the preferred range is 3 μm to 10 μm. This is because if the groove depth is greater than the diameter of the magnetic wire, it becomes difficult to form the upper coil.

Through this process, 7a of intermediate step product 1 comprising groove forming portion 7Ga and alignment mark portion 7Aa is formed.
The groove forming portion 7Ga is composed of a positive resist 73Ga and a rectangular parallelepiped groove 73Ga. The alignment mark portion 7Aa is composed of a positive resist 73Aa and an elongated rectangular parallelepiped concave portion 74Aa.

b) As shown in FIG. 7(b), the intermediate step product 1 is subjected to a curing heat treatment to form an intermediate step product 2.
The curing heat treatment is performed at a temperature of 250 to 350.degree. If the temperature is 250° C. or less, curing may be insufficient and the shape may change in a post-process.
Considering shrinkage and deformation due to curing heat treatment, the thickness of the positive resist is preferably about 3 μm to 15 μm, which is the same as or slightly thicker than the groove depth.

Through this process, 7b of the intermediate step product 2 including the groove forming portion 7Gb and the alignment mark portion 7Ab is formed.
The groove forming portion 7Gb is composed of a positive resist 73Gb hardened by a curing process and an inverted trapezoidal shape 74Gb changed from a rectangular parallelepiped shape by stress generated during the curing process.
The alignment mark portion 7Ab is composed of a positive resist 73Ab hardened by a curing heat treatment and an inverted trapezoidal concave portion 74Ab.

c) Here, there is a concern that the visibility of the mark may deteriorate due to the concave portion of the alignment mark having an inverted trapezoidal shape. Therefore, after coating the entire surface with the resin of the intermediate step product 2, mask exposure and development are performed to protect areas other than the alignment portion with resin, and RIE processing is performed using the positive resist 73Ac of the alignment mark portion as a mask to perform alignment. By digging the SiO2 film existing at the bottom of the mark, an intermediate step product 3 having a steep dug edge is formed. After that, the resin protecting areas other than the alignment mark is removed.

Through this process, 7c of the intermediate step product 3 including the groove forming portion 7Gc and the alignment mark portion 7Ac is formed.
The grooved portion 7Gc is the same as the grooved portion 7Gb of the intermediate step product 2 .
The alignment mark portion 7Ac is composed of a lowered positive resist 73Ac and an inverted trapezoidal concave portion 74Ac formed by forming a steep edge on a portion of the SiO2 film 72 .

d) Next, a negative resist-based resin film is applied, exposed and developed to leave the resin film only in the grooves, and cured by heat treatment to form an R shape at the bottom of the grooves. A film is deposited to form an intermediate step product 4 .
The metal film formed in the groove forming portion is formed for the lower coil. The thickness of the metal film is about 0.2 to 1 μm, and is determined according to the predetermined thickness of the lower coil. At this time, since the metal film is also formed on the alignment mark portion, it is utilized as a reflective film for the recess for alignment to form a plurality of highly visible alignment marks.

e) As shown in FIG. 8, the lower coil of the GSR element is formed by using the intermediate step product 4 consisting of the groove forming portion and the alignment mark forming portion on which the metal film is formed.
Using the alignment marks 8A and the reflective film 8B, resin coating, exposure, development, plating, and etching processes are performed to remove the resin forming the coil. to form

F) Next, after placing the magnetic wire 56 on the upper part of the lower coil 55 (75) and fixing it in the groove 54 with an insulating resin, the upper coil 57 is formed again using the alignment marks to form the GSR element. manufacture.
The alignment accuracy between the alignment mark and the plurality of masks is 1 μm or less, preferably 0.5 μm or less.

Further, when the magnetic wire 56 is placed above the lower coil 55, the magnetic wire is placed under a tension of 30 to 100 kg/mm ² , the magnetic wire is embedded in the groove with resin, and is heated to a temperature of 250 to 350°C. A curing heat treatment at temperature may be applied to fix the magnetic wire. By subjecting the magnetic wire 56 to such tension heat treatment, it becomes possible to improve the magnetic properties such as the improvement of the GSR properties. Here, the GSR characteristic means that the dependence of the output on the magnetic field exhibits a sine function relationship and does not exhibit a hysteresis characteristic.

In other words, the present invention is a method for directly manufacturing a GSR element on an ASIC substrate, the GSR element having a coil pitch of 10 μm or less in which a magnetic wire is wound around a resin film on the ASIC substrate.
A schematic diagram of a GSR device fabricated directly on an ASIC substrate according to the present invention is shown in FIG.
It should be noted that the present invention is a general-purpose method of directly manufacturing an element composed of a magnetic wire, a coil encircling the magnetic wire, and electrode wiring on an ASIC substrate, so it is limited to the method of manufacturing a GSR element. is not.

A process flow for simultaneously forming grooves and alignment marks in a resin film on an ASIC substrate will be described.
Step (a):
First, in order to form grooves and alignment marks on an ASIC substrate, a positive resist resin film is applied to a thickness of 10 μm. After that, exposure and development are performed using a mask material in which a pattern of grooves and a plurality of alignment marks are arranged to form the intermediate step product 1 shown in FIG. 4(a). The mask also has a pattern in which the electrodes of the ASIC substrate are also opened.
At this time, the shape of the groove is a rectangular parallelepiped.

Step (b):
Next, a curing heat treatment is performed at 280° C. for 1 hour to harden the resin film and form the intermediate step product 2 shown in FIG. 4(b). After the curing process, the groove changes from a rectangular parallelepiped shape to an inverted trapezoidal shape as shown in FIG. 4B due to the stress generated during the curing process.
At this time, the groove depth is 7 μm.

Step (c):
Here, in order to sharpen the shape of the alignment mark, after coating the entire surface with resin, mask exposure and development are performed, and areas other than the alignment portion are protected with a resist.

Step (d):
O2-RIE is performed by masking the alignment recesses themselves formed in the step (a), and then the resist is stripped off to sharpen the shape of the alignment marks as shown in the intermediate step product 3 in FIG. 4(c).

Step (e):
A negative resist resin film is applied, exposed and developed to leave the resin film only in the grooves, and cured heat treatment is performed to form an R shape at the bottom of the grooves. A 2 μm film is formed.

Step (f):
A resin is applied to the entire ASIC substrate on which the metal film is formed, a pattern for forming a lower coil is arranged in the groove, and exposure and development are performed using the alignment pattern. At this time, a pattern for protecting the alignment portion is arranged on the mask.

Step (g):
After plating, removing the resin film, and etching the metal film other than the lower coil portion, the metal film in the groove forming portion forms the lower coil 55 . The metal film 8B of the alignment mark portion functions as a reflective film. This state is shown in FIG.

Step (h):
A magnetic wire 56 covered with glass is placed in the groove 54 with a tension of 30 to 100 kg/mm 2 , and the wire is temporarily fixed to a jig with an adhesive or tape while maintaining the tension. After that, a negative resist type resin is applied, the wires are temporarily fixed in the grooves at 90° C., and after exposure, baking, and development, curing heat treatment is performed at 280° C. for 1 hour to fix them in the grooves. At this time, the magnetic wire is heat-treated while maintaining tension, so that the GSR characteristics can be improved.

Step (i):
Through a plurality of steps (not shown), a metal film of 0.2 μm is formed over the entire ASIC substrate in order to form the upper side of the coil that surrounds the magnet 56 .

Step (j):
Further, resin is applied to the entire ASIC substrate, and exposure and development are performed using a mask having patterns for forming lead lines of coils and wire conduction portions in the grooves, thereby forming the upper coil 57 . Alignment with the lower coil 55 can be performed without any problem by using the alignment mark 8A at the time of exposure.

Step (k):
The metal film in the grooved portion functions as the upper coil 57 through plating, resin film removal, and etching of the metal film other than the upper coil portion.

By the above process, the groove for forming the inverted trapezoidal lower coil and the alignment mark concave portion can be simultaneously formed in the resin film, and the highly visible alignment mark can be formed on the resin film. It is possible to integrally form a GSR element having

The present invention integrates a GSR element and an ASIC to realize an ultra-thin and ultra-compact GSR sensor, and is used in applications that require ultra-compact and high performance, such as in-vivo motion devices. There is expected.
It can also be applied to small, high-performance GSR sensors for automobiles, wearable computers, and the like.

1: Si substrate groove forming member 11: Si <100> substrate 12: Thermal oxide film 13: Inverted trapezoidal groove 2: SiO2 insulating film groove forming member 21: ASIC substrate 22: Protective coating (SiO2) , 23: SiO2 insulating film, 24: rectangular parallelepiped groove 3: negative resist groove forming body 31: ASIC substrate, 32: protective film (SiO2), 33: negative resist 4: rectangular parallelepiped groove 41: positive resist groove Formed body (after photolithography)
411: ASIC substrate, 412: protective coating (SiO2), 413: positive resist, 414 rectangular parallelepiped groove 4: rectangular parallelepiped groove 42: positive resist groove forming body (after curing)
421: ASIC substrate, 422: protective coating (SiO2), 423: positive resist, 424 inverted trapezoidal groove 5: GSR element 50: R shape at the bottom of the inverted trapezoidal groove, 51: ASIC substrate, 52: protective coating ( SiO2), 53: positive resist, 54: inverted trapezoidal groove, 55: lower coil, 56: magnetic wire, 57: upper coil, 58: negative resist resin coating for fixing the magnetic wire in the groove, 59: groove positive resist-based resin film 60 for eliminating the step between the wire and the substrate: GSR element forming substrate (intermediate process product)
61: ASIC substrate, 62: protective film (SiO2), 63: positive resist,
6G: groove forming portion, 63G: positive resist, 64G: inverted trapezoidal groove,
6A: Alignment Forming Portion 6a: Alignment Mark (+ Mark) 63A: Positive Resist 64A: Inverted Trapezoidal Concave 7a: Intermediate Form 1
71: ASIC substrate, 72: protective coating (SiO2), 73a: positive resist,
7Ga: groove forming portion, 73Ga: positive resist, 74Ga: rectangular parallelepiped groove,
7Aa: Groove Forming Portion 73Aa: Positive Resist 74Aa: Cuboid Concave 7b: Intermediate Form 2
71: ASIC substrate, 72: protective coating (SiO2), 73b: positive resist,
7Gb: groove forming portion, 73Gb: positive resist, 74Gb: inverted trapezoidal groove,
7Ab: Groove Forming Portion 73Ab: Positive Resist 74Ab: Cuboid Concave 7c: Intermediate Form 3
71: ASIC substrate, 72: protective film (SiO2), 73c: positive resist,
7Gc: groove forming portion, 73Gc: positive resist, 74Gc: inverted trapezoidal groove,
7Ac: groove forming portion, 73Ac: positive resist, 74Ac: inverted trapezoidal concave portion 8: lower coil forming body 81: ASIC substrate, 82: protective coating (SiO2), 83: positive resist,
84: Inverted trapezoidal groove, 85: Lower coil, 86: Negative resist resin film for fixing the magnetic wire in the groove 8A: Alignment mark, 8B: Reflective film

Claims (2)

A magnetic wire, a detection coil having a coil pitch of 10 μm or less consisting of a lower coil and an upper coil surrounding the magnetic wire, and a GSR element consisting of electrodes are directly mounted on a substrate of an application specific integrated circuit (hereinafter referred to as ASIC). In the method of manufacturing
(1) A positive resist type resin film is applied onto the ASIC substrate, exposed and developed to simultaneously form grooves for placing the magnetic wires and a plurality of concave portions for alignment marks in the resin film, followed by curing heat treatment. After curing to form inverted trapezoidal grooves and recesses for alignment marks, a negative resist resin coating is applied, exposed and developed to leave the resin coating only in the inverted trapezoidal grooves, and a curing heat treatment is performed. forming an R shape at the bottom of the groove,
(2) forming an alignment mark with high visibility by forming a metal film and using the metal film as a reflective film for the concave portion of the alignment mark;
(3) forming the lower coil along the surface of the inverted trapezoidal groove using the alignment mark and the metal film covering the inverted trapezoidal groove;
(4) the magnetic wire is placed while tension is applied to the inverted trapezoidal groove in which the lower coil is formed, temporarily fixed with resin, and then fixed by curing heat treatment;
(5) removing the insulating glass covering the wire in the wire electrode portion for joining the wire and the electrode wiring by CF ₄ -RIE;
(6) applying a positive resist-based resin coating to the entire surface of the substrate, exposing and developing to leave the positive resist-based resin coating only in the grooves and the magnetic wire portions, and performing a curing heat treatment to smooth the steps;
(7) forming the upper coil and electrodes;
(8) A method of manufacturing a GSR element, wherein an assembly of the GSR element comprising the magnetic wire, the detection coil and the electrode is separated into individual pieces.
In step (4) as recited in claim 1,
The magnetic wire is placed on the lower coil with a tension of 30 to 100 kg/mm ² applied, the magnetic wire is embedded in the groove with resin, and subjected to tension heat treatment at a temperature of 250 to 350° C. A method of manufacturing a GSR element, comprising fixing a magnetic wire and improving GSR characteristics at the same time.

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