JP2007252124A - Electromagnetic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic actuator requiring a small number of manufacturing steps with a low manufacturing cost. <P>SOLUTION: In the electromagnetic actuator 10 where a framelike supporting portion 11, a movable portion 13, and a pair of torsion bars 12 and 12 supporting the movable portion 13 to oscillate are formed integrally of a semiconductor substrate, a drive coil and a reflector 15 are provided at the movable portion, a pair of permanent magnets 17 and 17 for applying a magnetostatic field are provided at the drive coil portion on the opposite sides parallel with the torsion bars 12 and 12 of the movable portion 13, and a pair of electrode terminals 16A and 16B of the drive coil are provided at the supporting portion 11, the connection end 16a of one electrode terminal 16A and the contact portion 14a at the coil pattern end on the movable portion 13 are made to conduct when the mirror is formed so that the reflector 15 also serves as a part of the drive coil. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic actuator using a semiconductor substrate, and more particularly to an electromagnetic actuator that can reduce the number of manufacturing steps and reduce manufacturing costs.

  Conventionally, as a planar electromagnetic actuator using a semiconductor substrate, a frame-shaped support portion, a movable portion, and a torsion bar that pivotally supports the movable portion within the frame of the support portion are integrally formed on the semiconductor substrate. The movable part is provided with a drive coil and a reflecting mirror, and the movable part parallel to the axial direction of the torsion bar is provided with, for example, a permanent magnet as a static magnetic field generating means for applying a static magnetic field to the drive coil portions on opposite sides. There is.

  Such an electromagnetic actuator is movable by electromagnetic force acting on both sides of the movable part parallel to the axial direction of the torsion bar due to the interaction between the magnetic field generated in the drive coil by the current supplied from the drive circuit and the static magnetic field by the permanent magnet. This is a configuration in which the light beam applied to the reflecting mirror is scanned by driving the unit, and can be applied to an optical switch, an optical scanning device, or the like. (For example, refer to Patent Document 1).

This type of electromagnetic actuator is manufactured by using a semiconductor manufacturing technique as described in Patent Document 2, for example, and an outline of a conventional manufacturing process is shown in FIGS. explain.
That is, in the step (a), a first layer coil pattern 2A and one electrode terminal region are formed on a semiconductor substrate (silicon substrate) 1. Next, in step (b), the insulating film 3 is formed on the coil pattern 2A except for the contact portion forming portion. Thereby, the contact part 2a is formed. In step (c), a second layer coil pattern 2B that is electrically connected to the first layer coil pattern 2A through the contact portion 2a and the other electrode terminal region are formed. Thereby, the above-described drive coil is formed. Next, in the step (d), the protective film 4 is formed on the second layer coil pattern 2B and part of each electrode terminal region. Thereby, a pair of electrode terminal portions 5A and 5B for electrically connecting the drive coil to an external circuit (not shown) by wire bonding is formed. In step (e), the semiconductor substrate portion excluding the frame-shaped support portion forming portion, the movable portion forming portion, and the torsion bar forming portion is removed by etching, and the frame-shaped support portion 6, the movable portion 7, and the pair of torsion bars 8 and 8 are formed. In the step (f), the reflecting mirror 9 is formed on the movable portion 7 to form a chip. When a material that does not require corrosion countermeasures such as gold (Au) is selected as the reflective mirror material, a protective film is not required, but when a material that requires corrosion countermeasures such as aluminum (Al) is selected. In this case, a step of forming a protective film on the reflection mirror 9 is added after the step (f).

JP 2003-153518 A JP 2006-42487 A

  By the way, in this electromagnetic actuator, it is necessary to increase the number of turns of the coil in order to increase the electromagnetic driving force. For this reason, conventionally, the coil formation process is performed a plurality of times, and the coil pattern is laminated to increase the number of turns of the coil. Therefore, as shown in FIG. 7, the conventional electromagnetic actuator requires at least six steps from coil formation to chip formation, and there is a problem that the number of manufacturing steps is large and the manufacturing cost is high.

  The present invention has been made paying attention to the above problems, and an object thereof is to provide an electromagnetic actuator with a small number of manufacturing steps and low manufacturing costs.

  For this reason, the invention of claim 1 integrally forms a frame-shaped support portion, a movable portion, and a torsion bar that pivotally supports the movable portion within the frame of the support portion with a semiconductor substrate, A pair of electrode terminals of the drive coil, the drive unit including a drive coil and a reflection mirror on the movable part, and a static magnetic field generating means for applying a static magnetic field to the drive coil parts on both sides of the movable part parallel to the torsion bar The drive coil is formed at the same time as the reflection mirror and includes a coil part that connects the electrode terminal and a coil pattern terminal on the movable part. It is characterized by that.

  In such a configuration, since the coil part that connects the coil pattern end on the movable part and the electrode terminal on the support part is formed simultaneously with the reflection mirror, the drive coil formation and the reflection mirror formation can be performed in the same process. The number of actuator manufacturing processes can be reduced.

  Specifically, as in claim 2, the drive coil is connected to the other of the pair of electrode terminals, and a first coil pattern provided on the movable part, and the first coil pattern on the first coil pattern A second coil pattern that is stacked via an insulating film and is electrically connected to the terminal end of the first coil pattern via a contact portion and is connected to one of the pair of electrode terminals, and the second coil pattern is It is preferable that the coil portion is formed at the same time as the reflection mirror.

  Further, as in claim 3, the drive coil includes a coil pattern connected to the other of the pair of electrode terminals and provided on the movable portion, and the reflection mirror is connected to the end of the coil pattern and the contact portion. It is also possible to form a laminated structure on the coil pattern via an insulating film so as to be conductive through the electrode and to be connected to one of the pair of electrode terminals, and the reflection mirror also serves as the coil part.

According to a fourth aspect of the present invention, the movable portion includes an inner movable portion including the reflection mirror and a frame-shaped outer movable portion provided outside the inner movable portion, and the outer movable portion is disposed outside the support portion. The inner movable part is pivotally supported by a torsion bar, and the inner movable part is pivotally supported by the outer movable part by an inner torsion bar orthogonal to the axial direction of the outer torsion bar.
In such a configuration, the light beam can be two-dimensionally scanned by the reflection mirror.

  In the case of the configuration of claim 4, as in claim 5, a first drive coil for driving the inner movable part and a second drive coil for driving the outer movable part are formed, and the first drive coil is It is good to set it as the structure provided with the said coil part.

As in claim 6, the reflecting mirror may be made of gold.
In such a configuration, a protective film as a countermeasure against reflection mirror corrosion is not necessary, and the protective film forming step can be omitted.

  According to the electromagnetic actuator of the present invention, since the electrode terminal and the coil pattern end of the drive coil on the movable part are electrically connected when the reflection mirror is formed, the reflection mirror serves as a part of the drive coil. A part of the forming process can be replaced with the reflecting mirror forming process, and the coil forming process that requires troublesome work such as patterning can be reduced. Therefore, there is an advantage that the number of manufacturing steps can be reduced and the manufacturing cost of the electromagnetic actuator can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a plan view of a first embodiment of an electromagnetic actuator according to the present invention.
In FIG. 1, an electromagnetic actuator 10 according to the present embodiment is supported by a frame-like support portion 11 through a pair of torsion bars 12, 12 so that a movable portion 13 can rotate. The support part 11, the torsion bars 12, 12 and the movable part 13 are integrally formed by a semiconductor substrate such as a silicon substrate. In the movable portion 13, a drive coil 14 (shown in FIG. 2) that generates a magnetic field by energizing the peripheral portion is covered with an insulating film 23 except for a contact portion 14a (indicated by a dotted line in the drawing) at the end of the coil pattern. Is laid. Further, a reflection mirror 15 formed of a metal material such as gold or aluminum is provided over the movable portion 13, the torsion bars 12 and 12, and the support portion 11.

  The support portion 11 is provided with a pair of electrode terminals 16A and 16B that are electrically connected to an external circuit by wire bonding, for example, and connect the drive coil 14 to the external circuit. One electrode terminal 16A is driven by a connection end 16a not covered with an insulating film 23 being connected to the contact portion 14a at the end of the coil pattern via the reflection mirror 15 and connected to the coil pattern on the movable portion 13. Connect to one end of the coil 14. The other electrode terminal 16 </ b> B is connected to the other end of the drive coil 14 by being integrally formed with the coil pattern on the movable portion 13. Therefore, the reflection mirror 15 also serves as a coil portion that connects the one electrode terminal 16A and the terminal end of the coil pattern on the movable portion 13.

  A pair of static magnetic fields acting on the drive coil portions of the opposite side portions of the movable portion parallel to the axial direction of the torsion bars 12, 12 outside the opposite side portions parallel to the axial direction of the torsion bars 12, 12 of the support portion 11. Permanent magnets 17 and 17 are provided as static magnetic field generating means so that opposite magnetic poles face each other. The static magnetic field generating means may be an electromagnet.

Next, with reference to FIG. 2, the manufacturing process of the electromagnetic actuator 10 of 1st Embodiment is demonstrated.
In step (a), the drive coil 14 and the pair of electrode terminal regions 22A and 22B are formed at predetermined positions on the silicon substrate 21. For example, after the front and back surfaces of the silicon substrate 21 are thermally oxidized, an aluminum thin film, for example, is formed on the oxide film by sputtering or the like, and the coil pattern of the drive coil 14, the pair of electrode terminal regions, and the contact part 14 a at the end of the coil pattern, respectively. The corresponding portion is masked with a positive resist, the aluminum thin film is etched, and then the positive resist is removed. Thus, the drive coil 14, the pair of electrode terminal regions 22A and 22B, and the contact portion 14a are formed.

  In the step (b), for example, photosensitive polyimide is applied and the drive coil portion excluding the contact portion forming portion and the electrode terminal regions 22A and 22B excluding the electrode terminal forming portion and the connection end forming portion are masked, and then polyimide Is removed, and the electrode terminal regions 22A and 22B excluding the drive coil 14 portion excluding the contact portion 14a and the electrode terminal forming portion and the connection end forming portion are covered with the insulating film 23. As a result, the contact portion 14a, the pair of electrode terminals 16A and 16B, and the connection end 16a are formed.

  In step (c), the portions of the silicon substrate 21 excluding the support portion forming portion, the movable portion forming portion, and the torsion bar forming portion are removed by etching. Thereby, the support part 11, a pair of torsion bars 12 and 12, and the movable part 13 are formed.

In the step (d), a reflective mirror 15 is formed by forming a gold thin film, for example, by vapor deposition or sputtering over the movable part 13, the torsion bars 12, 12 and the support part 11 including the connection end 16a and the contact part 14a. To do. As a result, the connection end 16a and the contact portion 14a are electrically connected via the reflection mirror 15, and the reflection mirror 15 also serves as a coil portion that electrically connects the terminal end of the coil pattern on the movable portion 13 and the electrode terminal 16A. become.
In addition, when the material which needs a countermeasure against corrosion, such as aluminum, is used as the reflecting mirror material, a protective film forming step may be provided after the step (d).

  According to the electromagnetic actuator 10 having such a configuration, the reflection mirror 15 serves as a part of the drive coil 14, and at the same time as the formation of the reflection mirror 15, the coil pattern of the drive coil 14 on the one electrode terminal 16 </ b> A and the movable portion 13 Are electrically connected to each other, so that the formation process of the second layer coil can be replaced with the reflection mirror formation process, and the troublesome coil formation process can be performed once. Therefore, there are advantages that the number of manufacturing steps can be reduced and the manufacturing cost of the electromagnetic actuator can be reduced. Also, if a material that does not require corrosion countermeasures such as gold is used as the reflective mirror material, the protective film forming step can be omitted.

  The operation of the electromagnetic actuator 10 is the same as in the prior art. When a current is supplied from the external drive circuit to the drive coil 14 on the movable portion 13, a magnetic field is generated, and the interaction between this magnetic field and the static magnetic field generated by the permanent magnets 17 and 17 is generated. Lorentz force is generated, and electromagnetic forces in opposite directions are generated on both sides of the movable part parallel to the axial direction of the torsion bars 12 and 12, and the movable part 13 rotates about the torsion bars 12 and 12 as axes. . The torsion bars 12 and 12 are twisted in accordance with this rotation operation, and a spring force is generated in the torsion bars 12 and 12, and the movable part is moved to a position where the spring force of the torsion bars 12 and 12 and the generated electromagnetic force are balanced. 13 rotates.

  If a direct current is passed through the drive coil 14, the movable portion 13 stops at a rotation position corresponding to the amount of current. Therefore, the rotation angle of the movable portion 13 is controlled according to the amount of current to deflect the light beam in a desired direction. Possible optical deflectors can be realized. When an alternating current such as a sine wave is passed through the drive coil 14, the movable part 13 swings, so that the light beam can be deflected and scanned by the reflection mirror 15. If the frequency of the alternating current supplied to the drive coil 14 is set to the resonance frequency of the oscillating motion of the movable portion 13, an optical scanning device capable of continuous scanning at a constant period can be realized.

Next, a second embodiment of the electromagnetic actuator of the present invention will be described.
FIG. 3 shows a plan view of the second embodiment. In addition, the same code | symbol is attached | subjected to the same element as 1st Embodiment.
In FIG. 3, the electromagnetic actuator 30 of the present embodiment is different from the first embodiment in the form of the drive coil 14, one electrode terminal 16A, and the reflection mirror 15, and the other configurations are the same as those in the first embodiment. Here, the form of the drive coil 14, one electrode terminal 16A, and the reflection mirror 15 will be described.

  As shown in the manufacturing process diagram of FIG. 4, the drive coil 14 is formed integrally with the electrode terminal 16B and electrically connected thereto, and the insulating film 23 is disposed on the first coil pattern 14A. A second coil pattern 14B is provided which is stacked and is electrically connected to the terminal end of the first coil pattern 14A via the contact portion 14a. The second coil pattern 14B, the reflection mirror 15, and the one electrode terminal 16A are integrally formed at the same time and are made of the same material. Therefore, the second coil pattern 14 </ b> B serves as a coil portion that connects the one electrode terminal 16 </ b> A and the terminal end of the first coil pattern of the drive coil 14.

With reference to FIG. 4, the manufacturing process of the electromagnetic actuator 30 of 2nd Embodiment is demonstrated.
In the step (a), the first coil pattern 14A and the electrode terminal 16B of the drive coil 14 are formed at predetermined positions on the silicon substrate 31 as in the step (a) in FIG.
In the step (b), as in the step (b) of FIG. 2, the insulating film 23 is formed on the first coil pattern 14A except for the contact portion forming portion and the electrode terminal forming portion.

  In the step (c), the lead portion connected to the electrode terminal 16A of the first coil pattern 14A and the electrode terminal 16B portion are masked, and a gold thin film is formed on the entire surface of the silicon substrate 31, for example, by vapor deposition or sputtering. As in the step a), the second coil pattern 14B of the drive coil 14, the reflection mirror 15, and the electrode terminal 16A are formed, and the mask of the lead portion and the electrode terminal 16B portion is removed. Accordingly, the first coil pattern 14A and the second coil pattern 14B are electrically connected via the contact portion 14a to form the drive coil 14, and the drive coil 14 is electrically connected to the electrode terminal 16A.

In the step (d), as in the step (c) of FIG. 2, the portions of the silicon substrate 31 excluding the support portion forming portion, the movable portion forming portion, and the torsion bar forming portion are removed by etching, thereby supporting the silicon substrate 31. A portion 11, a pair of torsion bars 12, 12 and a movable portion 13 are formed.
In addition, when the material which needs a countermeasure against corrosion, such as aluminum, is used as the reflective mirror material, a protective film forming step may be provided after the step (c) or (d).

  Similarly to the first embodiment, the electromagnetic actuator 30 having such a configuration has an advantage that the number of manufacturing steps can be reduced and the manufacturing cost of the electromagnetic actuator can be reduced. Also, if a material that does not require corrosion countermeasures such as gold is used as the reflective mirror material, the protective film forming step can be omitted.

Next, a third embodiment of the electromagnetic actuator of the present invention will be described.
FIG. 5 is a plan view of a two-dimensional type that is the third embodiment of the present invention.
In FIG. 5, in the electromagnetic actuator 40 of the third embodiment, a frame-shaped outer movable portion 43A is pivotally supported by a frame-shaped support portion 41 via a pair of outer torsion bars 42A, 42A. . A flat plate-shaped inner movable portion 43B is pivotally supported on the outer movable portion 43A via a pair of inner torsion bars 42B and 42B orthogonal to the axial direction of the outer torsion bars 42A and 42A. The support part 41, the outer and inner torsion bars 42A, 42A, 42B, 42B and the outer and inner movable parts 43A, 43B are integrally formed of a semiconductor substrate such as a silicon substrate. An outer drive coil 44A (shown in FIG. 6), which is a second drive coil that generates a magnetic field when energized, is laid on the outer movable portion 43A, and a first magnetic field that generates a magnetic field when energized is provided on the inner movable portion 43B. An inner drive coil 44B (shown in FIG. 6), which is a drive coil, is provided. The outer drive coil 44A is entirely covered with an insulating film 52, and the inner drive coil 44B is covered with the insulating film 52 except for contact portions 44a and 44b (shown by dotted lines in the figure) at both ends of the coil pattern. .

  The support 41 includes a pair of outer electrode terminals 45A and 45B and a pair of inner electrode terminals for connecting the outer drive coil 44A and the inner drive coil 44B to the external circuit by being electrically connected to the external circuit by, for example, wire bonding. 46A and 46B are provided, respectively. The outer drive coil 44A is directly electrically connected to the outer electrode terminals 45A and 45B. The inner drive coil 44B has its contact portions 44a, through a reflection mirror 47 made of a metal material such as gold or aluminum formed over the inner movable portion 43B, the outer movable portion 43A, the outer torsion bars 42A, 42A and the support portion 41. 44b and the inner electrode terminals 46A and 46B are electrically connected. Accordingly, the reflection mirror 47 also serves as a coil portion that connects the inner electrode terminals 46A and 46B and the terminal end of the coil pattern on the inner movable portion 43B.

  A pair of permanent magnets 48A, 48A parallel to the axial direction of the outer torsion bars 42A, 42A and a pair of permanent magnets 48B, 48B parallel to the axial direction of the inner torsion bars 42B, 42B are provided outside the support portion 41. However, they are provided such that the opposite magnetic poles face each other. These apply a static magnetic field to the drive coil portions on both sides of the outer movable portion and the drive coil portions on both sides of the inner movable portion.

Next, with reference to FIG. 6, the manufacturing process of the electromagnetic actuator 40 of 3rd Embodiment is demonstrated.
In the step (a), as in the first embodiment, the outer drive coil 44A, the inner drive coil 44B, the outer electrode terminals 45A and 45B, the inner electrode terminals 46A and 46B, and the contact portion 44a are arranged at predetermined positions on the silicon substrate 51. , 44b. Here, the outer drive coil 44 </ b> A is formed by drawing a coil pattern on the support portion forming portion via the outer torsion bar forming portion of the silicon substrate 51 in order to form a plurality of turns in one coil forming step. Further, the inner drive coil 44B is also formed with a plurality of turns in the inner movable portion forming portion in one coil forming step.

  In the step (b), the outer drive coil 44A portion and the inner drive coil 44B portion excluding the outer electrode terminals 45A and 45B, the inner electrode terminals 46A and 46B, and the contact portions 44a and 44b are covered with an insulating film 52.

  In the step (c), the portions of the silicon substrate 51 excluding the support portion forming portion, the inner and outer movable portion forming portions, and the torsion bar forming portion are removed by etching. Thereby, the support part 41, a pair of inner and outer torsion bars 42A, 42A, 42B, 42B and inner and outer movable parts 43A, 43B are formed.

In the step (d), the reflection mirror 47 is formed by, for example, forming a gold thin film by vapor deposition or sputtering so that the contact portions 44a and 44b and the inner electrode terminals 46A and 46B are electrically connected by the reflection mirror 47. As a result, the inner drive coil 44B and the inner electrode terminals 46A and 46B are electrically connected via the reflection mirror 47 as a part of the inner drive coil 44B.
In addition, when the material which needs a countermeasure against corrosion, such as aluminum, is used as the reflecting mirror material, a protective film forming step may be provided after the step (d).

  Also in the case of the two-dimensional type electromagnetic actuator 40 having such a configuration, it is possible to reduce the troublesome coil forming process as compared with the conventional case by adopting a configuration in which the reflection mirror 47 also serves as a part of the inner drive coil 44B. Therefore, there is an advantage that the number of manufacturing steps can be reduced and the manufacturing cost of the electromagnetic actuator can be reduced.

  The operation principle of the two-dimensional type electromagnetic actuator 40 is the same as that of the one-dimensional type of the first and second embodiments, and the mutual magnetic field generated by energizing the outer drive coil 44A and the static magnetic field by the permanent magnets 48A and 48A. Due to the action, the outer movable portion 43A rotates about the outer torsion bars 42A and 42A as the axis center, and the inner movable portion is caused by the interaction between the magnetic field generated by energizing the inner drive coil 44B and the static magnetic field by the permanent magnets 48B and 48B. 43B rotates around the inner torsion bars 42B, 42B as the axis center.

The top view which shows 1st Embodiment of the electromagnetic actuator which concerns on this invention Explanatory drawing of the manufacturing process of 1st Embodiment The top view which shows 2nd Embodiment of the electromagnetic actuator which concerns on this invention Explanatory drawing of the manufacturing process of 2nd Embodiment The top view which shows 3rd Embodiment of the electromagnetic actuator which concerns on this invention Explanatory drawing of the manufacturing process of 3rd Embodiment Explanatory drawing of manufacturing process of conventional electromagnetic actuator

Explanation of symbols

10, 30, 40 Electromagnetic actuators 11, 41 Support parts 12, 42A, 42B Torsion bars 13, 43A, 43B Movable parts 14, 44A, 44B Drive coils 14a, 44a, 44b Contact parts 15, 47 Reflection mirrors 16A, 16B, 45A , 45B, 46A, 46B Electrode terminals 17, 48A, 48B Permanent magnet (static magnetic field generating means)

Claims (6)

A frame-shaped support portion, a movable portion, and a torsion bar that pivotally supports the movable portion within the frame of the support portion are integrally formed on a semiconductor substrate, and a drive coil and a reflection mirror are formed on the movable portion. An electromagnetic field generating means for applying a static magnetic field to the drive coil portions of the opposite sides parallel to the torsion bar of the movable portion, wherein the pair of electrode terminals of the drive coil are provided on the support portion. An actuator,
An electromagnetic actuator characterized in that the drive coil includes a coil portion that is formed at the same time as the reflection mirror and connects the electrode terminal and a terminal end of a coil pattern on the movable portion.   The drive coil is connected to the other of the pair of electrode terminals, and a first coil pattern provided on the movable part, and the first coil is laminated on the first coil pattern via an insulating film. A second coil pattern that is electrically connected to the end of the pattern via the contact portion and is connected to one of the pair of electrode terminals, and the second coil pattern is formed simultaneously with the reflection mirror to form the coil portion. The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is formed.   The drive coil includes a coil pattern connected to the other of the pair of electrode terminals and provided on the movable portion, and the reflection mirror is electrically connected to the terminal end of the coil pattern via a contact portion and the pair of pairs. 2. The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is laminated on the coil pattern via an insulating film so as to be connected to one of the electrode terminals, and the reflection mirror also serves as the coil portion.   The movable portion includes an inner movable portion including the reflection mirror and a frame-shaped outer movable portion provided outside the inner movable portion, and the outer movable portion can be rotated on the support portion by an outer torsion bar. The structure according to any one of claims 1 to 3, wherein the inner movable part is pivotally supported on the outer movable part by an inner torsion bar orthogonal to the axial direction of the outer torsion bar. Electromagnetic actuator.   The electromagnetic according to claim 4, wherein a first drive coil for driving the inner movable part and a second drive coil for driving the outer movable part are formed, and the first drive coil includes the coil part. Actuator.   The electromagnetic actuator according to claim 1, wherein the reflection mirror is made of gold.

Images