JP4376679B2 - Planar actuator manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a planar actuator that deflects a light beam.

  In a conventional planar type actuator that deflects a light beam, a movable part formed with a mirror surface that reflects light on one main surface is pivotally supported on a fixed part so as to be rotatable by a beam part. A drive means is composed of a coil laid along and a permanent magnet placed facing the opposite side parallel to the axis of the beam with a movable part in between, and the coil is energized to generate Lorentz force In some cases, the movable part is rotated to reflect and deflect the light beam on the mirror surface.

  24A and 24B are diagrams showing the configuration of a conventional planar actuator, where FIG. 24A is a front sectional view, FIG. 24B is a top view, and FIG. 24C is a bottom view. The silicon substrate 101 is integrally formed with a flat movable plate 102 and torsion bars 103 and 104 that pivotally support the movable plate 102 with respect to the silicon substrate 101 so as to be rotatable in the vertical direction of the substrate. A planar coil 105 that generates a magnetic field when energized is laid on one surface of the movable plate 102, and a mirror 106 is provided on the other surface. Reference numeral 107 denotes a base substrate, and the silicon substrate 101 is directly mounted with the mirror 106 side provided on the movable plate 102 facing downward (base substrate side). Reference numeral 107 a denotes a hole corresponding to the mirror 106 provided on the base substrate 107. Reference numeral 108 denotes a wire, which connects the wire connection pad 109 provided on the silicon substrate 101 and the pattern 107b provided on the base substrate 107 by wire bonding to form an electrical connection between the silicon substrate 101 and the base substrate 107. .

  A pair of permanent magnets 110 and 111 for applying a magnetic field to opposite sides of the movable plate 102 are fixed to the base substrate 107 at positions parallel to the axial direction of the torsion bars 103 and 104. A yoke 112 is placed on the peripheral edge portion to constitute a planar actuator.

  When the planar coil 105 formed on the movable plate 102 is energized, the movable plate 102 rotates around the torsion bars 103 and 104 as rotation centers.

  Next, the silicon substrate 101 of the planar actuator (hereinafter referred to as a planar actuator chip) will be described. 25A and 25B are views showing the planar actuator chip 101, where FIG. 25A is a top view, FIG. 25B is a bottom view, and FIG. 25C is a cross-sectional view taken along line A-A ′. FIG. 26 is a diagram illustrating a manufacturing process of the planar actuator chip 101. FIG. The planar actuator chip 101 is manufactured through steps a to i. Hereinafter, each process will be described. The coil 118 is simplified for the sake of explanation.

Step a (oxide film forming step): a silicon bonded substrate 113 having a thickness of 500 μm (commonly called an SOI substrate, for example, an active layer 114 (100 μm), an intermediate layer 115 (1 μm) made of a silicon oxide film, and a support substrate 116 (400 μm). )) Is thermally oxidized to form a silicon oxide film (1 μm) 117.
Step b (coil pattern forming step): Each pattern of the coil 118, the insulating film 119, and the protective film 120 is sequentially laminated on the upper surface side of the substrate by photolithography and etching.
Step c (oxide film removing step 1): Except for the frame portion forming portion, the torsion bars 103 and 104 forming portion, and the movable plate 102 forming portion on the upper surface of the substrate, the exposed silicon oxide film 117 is removed by etching.
Step d (active layer removal step): The active layer silicon 114 exposed by the etching in the step c is removed by etching.
Step e (Intermediate Layer Removal Step 1): The intermediate layer silicon oxide film 115 exposed by the etching in the step d is removed by etching.
Step f (oxide film removal step 2): A portion of the silicon oxide film 117 excluding the end of the support substrate silicon 116 is removed by etching.
Step g (supporting substrate removing step): The supporting substrate silicon 116 exposed by the etching in the step f is removed by etching. In the anisotropic etching, the etching rate is selected between silicon and the silicon oxide film. Therefore, when the etching reaches the intermediate silicon oxide film 115 on the lower surface of the movable plate 102, the etching is apparently terminated. The penetration part is completely removed.
Step h (intermediate layer removal step 2): The intermediate layer silicon oxide film 115 exposed by the etching in the step g is removed by dry etching.
Step i (mirror formation step): A total reflection mirror 121 is formed on the lower surface of the active layer silicon 114 exposed by the etching in step h by vapor deposition or sputtering. The planar type actuator chip 101 is manufactured by such a process. Usually, a large number of planar type actuator chips 101 are simultaneously formed on a large wafer like a semiconductor element, and are divided individually after completion.

  Next, the resonance frequency (hereinafter simply referred to as frequency) of the movable plate of the planar actuator will be described. The frequency of the movable plate is determined by the torsion bar and the movable plate shape. The characteristics of the torsion bar are determined by the cross-sectional aspect ratio, cross-sectional area, length, and material. In particular, the aspect ratio and cross-sectional area of the cross section are important. Nonetheless, it is a part that is most susceptible to processing conditions, so it is difficult to achieve accuracy. The shape of the movable plate is less affected than the torsion bar, but it is processed with the same precision as the torsion bar. These are very likely to cause cracking and chipping when the accuracy is increased by a mechanical frequency adjusting method using lapping, and the reliability is remarkably lowered. Here, with respect to the problems as described above, there is disclosed a manufacturing method for adjusting a frequency by processing a movable plate and a torsion bar of a planar actuator whose frequency is measured in advance (for example, Patent Document 1). reference).

  In Patent Document 1, in order to reduce the frequency of the movable plate, the active layer 114 on the movable plate and the torsion bar is etched in step h in FIG. Usually, when the torsion bar is etched to reduce the thickness, the frequency changes in a decreasing direction. On the other hand, when the movable plate is etched to reduce the thickness, the load mass on the movable plate is reduced and the frequency is changed in the increasing direction. However, in this case, the former effect is dominant, and the frequency generally changes in a decreasing direction. Here, the etching amount and the frequency reduction amount with respect to the movable plate and the torsion bar are in a proportional relationship. In Patent Document 1, in order to increase the frequency of the movable plate, a metal mirror is formed on the movable plate and the torsion bar (metal film formation) in step i in FIG. Again, as in the case of reducing the frequency, the direction of frequency change is reversed between the processing to the movable plate and the processing to the torsion bar, but the effect of frequency reduction due to the increased load mass due to the formation of the metal film on the movable plate. Rather, the effect of increasing the frequency due to the torsion bar becoming thicker due to the film formation is more dominant, so the frequency generally increases. Here, the metal film formation amount and the frequency increase amount with respect to the movable plate and the torsion bar are in a proportional relationship.

Conventionally, as described above, in the intermediate layer removing process and the mirror forming process in the planar actuator chip manufacturing process, when the initial frequency of the planar actuator chip deviates from the set frequency, the frequency deviation amount of the planar actuator chip is corrected. An appropriate amount of etching and metal film formation are performed to match the set frequency.
JP 2002-228965 A

  In the conventional planar actuator manufacturing method, etching or metal film formation is performed on the movable plate (mirror surface side) and the torsion bar until the frequency is changed to a desired frequency. However, this method has the following problems. It was. As described above, when the same processing is applied to the movable plate and the torsion bar, the amount of change in frequency indicates a change in the opposite direction between the movable plate and the torsion bar. This means that the frequency changes of the movable plate and the torsion bar cancel each other, and the adjustment efficiency is lower than when each portion is processed independently. For this reason, when a large adjustment amount is desired, it is necessary to perform a large amount of etching or metal film formation. However, if the movable plate (mirror surface side) is excessively etched, the silicon surface of the movable plate becomes rough. Similarly, when the film is excessively formed, the film particles are aggregated to form fine irregularities on the film surface. When the reflection mirror is formed in the next step in this state, the roughness or irregularity of the base is reflected on the reflection mirror surface, which adversely affects optical characteristics such as reflectance. Further, when the etching is excessively performed on the torsion bar, the silicon surface becomes rough, which causes the torsion bar to break during driving. Further, when the film is excessively formed on the torsion bar, the thin film deposited on the surface of the torsion bar is peeled off and the driving characteristics are lowered due to the bimetallic effect caused by the difference in thermal expansion coefficient between the silicon and the metal thin film.

  In addition, a conventional planar actuator manufacturing method includes a one-dimensional drive system in which a movable plate and a torsion bar that pivotally supports the movable plate with respect to the substrate are integrally formed on the substrate, and the movable plate is swung. For the planar type actuator, it is possible to adjust the frequency of the movable plate to a desired value by increasing and decreasing the frequency of the movable plate, but the movable plate is pivoted to the semiconductor substrate by the first torsion bar. A frame-shaped outer movable plate that is supported, and an inner movable plate that is pivotally supported on the inner side of the outer movable plate by a second torsion bar that is orthogonal to the first torsion bar, the inner movable plate, When the adjusting means is used for a planar actuator of a two-dimensional drive system that swings the outer movable plate, the frequencies of the inner movable plate and the outer movable plate change at a constant rate in the same direction. Therefore, the inner movable plate and the outer movable plate cannot be adjusted at an arbitrary frequency ratio. Furthermore, the frequency cannot be adjusted in the opposite direction between the inner movable plate and the outer movable plate.

  The present invention has been made in view of the above problems, and the shape of the movable plate and the torsion bar is out of the dimensional tolerance in the previous process, and even if the frequency deviates from the target value, the movable plate and the torsion bar can be efficiently used. It is an object of the present invention to provide a method for manufacturing a planar actuator having a frequency adjusting means that has little influence on quality and is compatible with both one-dimensional and two-dimensional drive systems.

Substrate, the movable plate and the movable plate formed integrally with the torsion bar to be rotatably supported to the substrate, in the manufacturing method of turning to pulp Lena actuator the movable plate, the resonance of the movable plate After measuring the frequency, when the measurement frequency is different from the desired resonance frequency, either one of the movable plate or the torsion bar is processed by film formation, and the other is processed by etching. The planar actuator manufacturing method is characterized in that the resonance frequency is adjusted to the desired resonance frequency .

When a mirror is formed on one surface of the movable plate, a frequency adjustment portion for frequency adjustment is provided on the other surface of the movable plate opposite to the mirror formation surface, and the film forming process is performed on the frequency adjustment portion. Alternatively, the etching process may be performed.

The movable plate is a frame-shaped outer movable plate that is pivotally supported on the semiconductor substrate by a first torsion bar, and a second torsion bar whose axial direction is orthogonal to the first torsion bar. In a manufacturing method of a planar actuator of a two-dimensional drive system, comprising a supported inner movable plate and rotating the inner movable plate and the outer movable plate , at least one of the inner movable plate and the second torsion bar is processed. after adjusting the resonant frequency of the inner movable plate by, by processing at least one of said outer movable plate and the first torsion bar to adjust the resonant frequency of the outer movable plate, the resonance frequency of the inner movable plate The processing for adjustment includes forming or etching one of the inner movable plate and the second torsion bar, or processing the inner movable plate and the second torsion bar. One of the two torsion bars is formed and the other is etched, and the processing for adjusting the resonance frequency of the outer movable plate is performed by either one of the outer movable plate or the first torsion bar. A planar actuator manufacturing method is characterized by forming or etching, or forming one of the outer movable plate and the first torsion bar and etching the other .

When forming a mirror on one surface of the inner movable plate, a frequency adjustment part for frequency adjustment is provided on the other surface of the inner movable plate opposite to the mirror forming surface, and the component is formed on the frequency adjustment part. Film processing or the etching processing may be performed.

  Since the frequency adjustment is performed after the planar type actuator chip is formed, the pattern accuracy and etching distribution are poor, and a chip whose frequency is out of the tolerance can be improved, so that the yield can be improved.

In flop Leena actuator, that each frequency to the torsion bar and movable plate for machining which varies in the same direction, can be adjusted efficiently frequency with a small processing amount, the torsion bar and movable by etching or deposition The burden on the board is reduced, and the influence on the quality can be minimized.

In flop Leena actuator, the movable plate, provided with a machined portion on the opposite side a mirror surface, by performing the frequency adjustment of the movable plate The machined portion by etching or deposition, without lowering the quality of the mirror surface Adjustment is possible.

  In a two-dimensional drive type planar actuator, the second torsion bar and / or the inner movable plate are processed, and then the first torsion bar and / or the outer movable plate are processed to move the inner movable plate and the outer movable plate. The frequency of the plate can be adjusted individually. Further, since the frequency can be adjusted efficiently with a small amount of processing, the burden on the torsion bar and the movable plate due to etching or film formation is reduced, and the influence on the quality can be minimized.

  In a planar actuator of a two-dimensional drive system, a mirror surface is provided by adjusting a frequency of the inner movable plate by providing a processing portion on the opposite surface of the inner movable plate to the mirror surface and etching or depositing the processed portion. Adjustment is possible without degrading the quality.

In the planar actuator manufacturing method, after measuring the resonance frequency of the movable plate, when the measurement frequency is different from the desired frequency, either the movable plate or the torsion bar is processed by film formation, and the other is etched. The planar actuator manufacturing method is characterized in that the frequency of the movable plate is adjusted to a desired frequency by processing . In the two-dimensional driving type planar actuator manufacturing method, after adjusting the frequency of the inner movable plate by processing at least one of the inner movable plate and the second torsion bar , the outer movable plate and the first torsion bar are adjusted . The frequency of the outer movable plate is adjusted by processing at least one, and the process for adjusting the frequency of the inner movable plate is to form or etch either the inner movable plate or the second torsion bar, or , One of the inner movable plate and the second torsion bar is formed and the other is etched, and the processing for adjusting the frequency of the outer movable plate is either the outer movable plate or the first torsion bar. Either deposit or etch one, or deposit either the outer movable plate or the first torsion bar and etch the other A method of manufacturing a planar type actuator, characterized in that is to grayed.

Hereinafter, a method for manufacturing a planar actuator of a one-dimensional drive system according to the first embodiment of the present invention will be described with reference to the drawings. Since the configuration of the one-dimensional driving type planar actuator of this embodiment is substantially the same as the configuration of the planar actuator shown in FIG. 24 , the description of the basic configuration is omitted here. The difference between the configuration of the conventional actuator and the planar actuator of the present embodiment is that the coil laid on the movable plate in the prior art is a movable plate single side (hereinafter, the coil forming surface of the movable plate is the movable plate main surface and the opposite surface is movable). In this embodiment, the coil is provided only at the peripheral edge of the movable plate.

  FIG. 1 is a cross-sectional view showing the manufacturing process of the planar actuator chip of the present invention. The cross-sectional view of FIG. 1 is the case where the coil on the movable plate is formed only on the peripheral edge of the movable plate in the A-A ′ cross section of the planar actuator chip shown in FIG. 2 and 3 are diagrams illustrating a process of decreasing the frequency when the frequency of the movable plate is higher than the setting. 4 and 5 are diagrams illustrating a process of increasing the frequency when the frequency of the movable plate is lower than the setting. The planar actuator chip is manufactured by using any one of steps a to i shown in FIG. 1 and a frequency adjusting step shown in FIGS. Hereinafter, each process will be described.

Step a (oxide film forming step): upper and lower surfaces of a silicon bonded substrate 113 having a thickness of 500 μm (for example, an active layer 114 (100 μm), an intermediate layer 115 (1 μm) made of a silicon oxide film, a support substrate 116 (400 μm)) Is thermally oxidized to form a silicon oxide film (1 μm) 117.
Step b (coil pattern forming step): Each pattern of the coil 118, the insulating film 119, and the protective film 120 is sequentially laminated on the upper surface side of the substrate by photolithography and etching. Here, the coil 118 is formed only in a portion that becomes the peripheral portion of the movable plate 102. The central portion of the movable plate 102 where the coil 118 is not formed is a frequency adjustment portion 123 (see FIGS. 3 and 5) that is processed in a subsequent frequency adjustment step.
Step c (oxide film removal step 1): Except for the frame portion forming portion, the torsion bars 103 and 104 forming portion, and the movable plate 102 peripheral portion forming portion on the upper surface of the substrate, the exposed silicon oxide film 117 is removed by etching. To do.
Step d (active layer removing step): Of the active layer silicon 114 exposed by the etching in step c, the portion excluding the central portion forming portion of the movable plate 102 is removed by etching.
Step e (Intermediate Layer Removal Step 1): The intermediate layer silicon oxide film 115 exposed by the etching in the step d is removed by etching.
Step f (oxide film removal step 2): The portion of the silicon oxide film 117 excluding the end portion of the support substrate silicon 116 is removed by etching.
Step g (supporting substrate removing step): The supporting substrate silicon 116 exposed by the etching in the step f is removed by etching. Since anisotropic etching has selectivity between silicon and silicon oxide film, the etching is apparently terminated when the etching reaches the intermediate layer 115 on the lower surface of the movable plate. Exit.
Step h (intermediate layer removal step 2): The intermediate layer 115 exposed by the etching in step g is removed by dry etching.

  When the process up to step h is performed, the frequency of the planar actuator chip is measured, and one of the frequency adjustment steps shown in FIGS. 2 to 5 is performed according to the difference between the measurement frequency and the set frequency. As an adjustment method for reducing the frequency of the movable plate, as shown in FIG. 2, the torsion bar is etched and thinned, and a metal film 122 is formed on the back surface of the movable plate to thicken the movable plate. Alternatively, as shown in FIG. 3, the torsion bar is etched and thinned, and a metal film 122 is formed on the frequency adjustment portion 123 provided on the main surface of the movable plate to thicken the movable plate. As an adjustment method for increasing the frequency of the movable plate, as shown in FIG. 4, a metal film 122 is formed on the torsion bar to increase the thickness, and the back surface of the movable plate is etched to decrease the thickness. Alternatively, as shown in FIG. 5, a metal film 122 is formed on the torsion bar to increase the thickness, and the frequency adjusting portion 123 provided on the main surface of the movable plate is etched to thin the movable plate. In this way, the frequency can be adjusted efficiently by processing the movable plate and the torsion bar using different processing methods such that the frequency change directions are the same.

  By the way, although the film formation of the metal film 122 is taken as an example as a means for thickening the movable plate and the torsion bar, this is not limited to the film formation by metal, and the film formation of resin or the like may be used. Hereinafter, the metal film 122 is formed on the movable plate or the torsion bar as described above.

  Also, when selectively processing only the torsion bar or the movable plate, the non-processed portion is masked using a stencil mask or directly processed using a laser or the like, so that photolithography is performed on the structure. It can be processed with high accuracy without using a masking process that is difficult and requires a lot of man-hours. Examples of the processing method include vapor deposition, sputtering, ion etching, laser ablation, and laser CVD. However, the processing method is not limited to this as long as it is a means that can uniformly process the adjusted portion.

  After the frequency adjustment step, as a step i, the total reflection mirror 121 is formed on the back surface of the movable plate by vapor deposition or sputtering to complete a planar actuator chip. Here, the total reflection mirror 121 is formed on the back surface of the movable plate, but the total reflection mirror 121 is formed on both sides of the frequency adjustment portion 123 of the movable plate main surface or the frequency adjustment portion 123 of the movable plate back surface and the movable plate main surface. May be.

  FIG. 6 is a top view of a planar actuator chip of a two-dimensional drive system. The silicon substrate 124 includes a frame-shaped outer movable plate 126 that is pivotally supported on the silicon substrate by a first torsion bar 125, and a second torsion bar 127 that is orthogonal to the first torsion bar 125 in the axial direction. An inner movable plate 128 that is pivotally supported on the inner side of the movable plate 126. A planar coil 129 that generates a magnetic field by energization is laid on one surface of the inner movable plate 128 and the outer movable plate 126, and the other surface. Is provided with a mirror (not shown) on its entire surface. A frequency adjustment portion 130 is provided inside the planar coil 129 on the inner movable plate 128. A wire connection pad 132 is provided on the frame portion 131 of the silicon substrate 124, and the planar coil 129 and the wire connection pad 132 are connected by a lead wire 133. The planar coil 129 is arranged in a simplified manner for explanation.

  The planar actuator of the two-dimensional drive system is provided with a pair of permanent magnets arranged in parallel with the first torsion bar 125 of the planar actuator chip formed as described above, with the outer movable plate 126 interposed therebetween, and a pair of permanent magnets. A permanent magnet is arranged in parallel with the second torsion bar 127 with an inner movable plate interposed therebetween. Then, by energizing the planar coil 129 of the inner movable plate 128 and the outer movable plate 126, the inner movable plate 128 and the outer movable plate 126 are connected to the second torsion bar 127, the first by the interaction with the static magnetic field of the permanent magnet. It rotates with the torsion bar 125 as a rotation axis.

  A method for manufacturing a planar actuator chip of a two-dimensional drive method will be described. FIG. 7 is a diagram showing a manufacturing process of a two-dimensional drive type planar actuator chip. FIG. 7 explains the manufacturing process by the A-A ′ cross section of the planar actuator chip of the two-dimensional drive system shown in FIG. 6. FIGS. 8 to 12 are diagrams illustrating a process of decreasing the frequency when the frequency of the inner movable plate is higher than the setting in the planar actuator of the two-dimensional drive method. FIGS. 13 to 17 are diagrams illustrating an adjustment process for increasing the frequency when the frequency of the inner movable plate is lower than the setting in the planar actuator of the two-dimensional drive method. 18 to 20 are diagrams illustrating a process of reducing the frequency when the frequency of the outer movable plate is higher than the setting in the planar electromagnetic actuator of the two-dimensional drive method. FIGS. 21 to 23 are diagrams illustrating a process of increasing the frequency when the frequency of the outer movable plate is lower than the setting in the planar electromagnetic actuator of the two-dimensional drive method. Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

Step a: A silicon bonded substrate 113 having a thickness of 500 μm (for example, active layer 114 (100 μm), intermediate layer 115 (1 μm) made of silicon oxide film, support substrate 116 (400 μm)) is thermally oxidized to form silicon. An oxide film (1 μm) 117 is formed.
Step b (coil pattern forming step): Each pattern of the coil 129, the insulating film 134, the lead wire 133, and the protective film 135 is sequentially laminated on the upper surface side of the substrate by photolithography and etching.
Step c (oxide film removal step 1): frame portion forming portion, first torsion bar 125 forming portion, second torsion bar 127 forming portion, outer movable plate 126 forming portion, inner movable plate 128 peripheral portion forming portion on the upper surface of the substrate Except for, the exposed silicon oxide film 117 is removed by etching.
Step d (active layer removal step): Of the active layer silicon 114 exposed by the etching in step c, the portion excluding the central portion forming the inner movable plate 128 is removed by etching.
Step e (Intermediate Layer Removal Step 1): The intermediate layer silicon oxide film 115 exposed by the etching in the step d is removed by etching.
Step f (oxide film removal step 2): A portion of the silicon oxide film 117 excluding the end of the support substrate silicon 116 is removed by etching.
Step g (supporting substrate removing step): The supporting substrate silicon 116 exposed by the etching in the step f is removed by etching. Since anisotropic etching has selectivity between silicon and silicon oxide film, when etching reaches the intermediate layer 115 on the lower surface of the movable plate, the etching is apparently terminated. Exit.
Step h (intermediate layer removing step 2): The intermediate layer 115 exposed by the etching in the step g is removed by dry etching.

  When the process up to step h is performed, the frequency of the planar actuator chip is measured. Depending on the difference between the measurement frequency and the set frequency, one or more of the frequency adjustment steps shown in FIGS. Select and implement sequentially.

  In order to decrease the frequency when the frequency of the inner movable plate is higher than the setting, any one of the steps of FIGS. 8 to 12 is performed. In the step shown in FIG. 8, the second torsion bar is thinned by etching. In the step shown in FIG. 9, a metal film 122 is formed on the back surface of the inner movable plate, and the inner movable plate is thickened. In the process shown in FIG. 10, the metal film 122 is formed on the frequency adjustment portion 130 provided on the main surface of the movable plate, and the movable plate is thickened. 11 and 12, the etching to the second torsion bar and the metal film 122 are formed on the back surface of the inner movable plate (FIG. 11), or the metal film 122 is formed on the frequency adjustment portion 130 (FIG. 12). ), The second torsion bar is made thinner and the inner movable plate is made thicker.

  In order to increase the frequency when the frequency of the inner movable plate is lower than the setting, any one of the steps of FIGS. 13 to 17 is performed. In the step shown in FIG. 13, a metal film 122 is formed on the second torsion bar, and the second torsion bar is thickened. In the step shown in FIG. 14, the back surface of the inner movable plate is etched to thin the inner movable plate. In the step shown in FIG. 15, the frequency adjustment portion 130 is etched and the inner movable plate is thinned. 16 and 17, the metal film 122 is formed on the second torsion bar and the back surface of the inner movable plate is etched (FIG. 16) or the frequency adjusting portion 130 is etched (FIG. 17). 2 Thicken the torsion bar and thin the inner movable plate.

  In order to decrease the frequency when the frequency of the outer movable plate is higher than the setting, the steps of FIGS. 18 to 20 are performed. In the step shown in FIG. 18, the first torsion bar is etched and thinned. In the process shown in FIG. 19, the metal film 122 is formed on the outer movable plate (movable plate rear surface side) to thicken the outer movable plate. In the step shown in FIG. 20, the etching of the first torsion bar and the metal film forming step on the outer movable plate are performed, respectively, to make the first torsion bar thinner and the outer movable plate thicker.

  In order to increase the frequency when the frequency of the outer movable plate is lower than the setting, the steps of FIGS. 21 to 23 are performed. In the step shown in FIG. 21, the metal film 122 is formed on the first torsion bar to be thick. In the step shown in FIG. 22, the outer movable plate (movable plate rear surface side) is etched to make the outer movable plate thinner. In the step shown in FIG. 23, the metal film 122 is formed on the first torsion bar and the outer movable plate is etched to thicken the first torsion bar and thin the outer movable plate.

  In the case of a planar actuator of a two-dimensional drive system, first, the frequency of the inner movable plate is adjusted according to the desired frequency change amount and direction, and then the same adjustment is made to the frequency of the outer movable plate. . When the frequency of the inner movable plate is adjusted after the frequency of the outer movable plate is adjusted first, the inner movable plate supported by the first torsion bar, the second torsion bar, and the frequency adjustment of the inner movable plate, This is because the total mass of the outer movable plate changes, and the frequency of the outer movable plate once adjusted changes with this change.

  As described above, the inner movable plate and the second torsion bar, and the outer movable plate and the first torsion bar are processed by using different processing methods such that the frequency change directions are the same, thereby effectively increasing the frequency. Can be adjusted.

  When only the torsion bar or the movable plate is selectively processed, as described in the first embodiment, the non-processed portion is masked using a stencil mask or directly processed using a laser or the like. Therefore, it can process with high precision. Examples of the processing method include vapor deposition, sputtering, ion etching, laser ablation, and laser CVD. However, the processing method is not limited to this as long as it is a means that can uniformly process the adjusted portion.

  After the frequency adjusting step, as a step i, a total reflection mirror 136 is formed by vapor deposition or sputtering to complete a planar actuator chip. Here, the total reflection mirror 136 is formed on the back surface of the movable plate. However, the total reflection mirror 136 is formed on both sides of the frequency adjustment portion 130 of the movable plate main surface or the frequency adjustment portion 130 of the movable plate back surface and the movable plate main surface. May be.

  In the meantime, in the first and second embodiments, the electromagnetic drive type planar actuator has been described. However, the present invention is not limited to this. For example, an upper electrode provided near the opposite side of the torsion bar and the upper electrode are opposed to each other. An electrostatic drive system may be used which is composed of a lower electrode disposed in a lower part of the movable part and which generates an electrostatic attractive force between both electrodes. Furthermore, it is composed of a thin film permanent magnet provided on the main surface of the movable plate and a coil disposed at a lower part of the movable plate, and is movable by the interaction between the vertical electromagnetic field by the coil and the static magnetic field of the thin film permanent magnet. A thin film magnet system in which the plate is rotated may be used.

The figure which shows the manufacturing process of the planar type actuator chip of this invention. The figure which shows the process of decreasing a frequency, when the frequency of a movable plate is higher than setting. The figure which shows the process of decreasing a frequency, when the frequency of a movable plate is higher than setting. The figure which shows the process of increasing a frequency, when the frequency of a movable plate is lower than setting. The figure which shows the process of increasing a frequency, when the frequency of a movable plate is lower than setting. The top view of a planar type actuator chip of a two-dimensional drive system. The figure which shows the manufacturing process of a two-dimensional drive system planar type actuator chip. The figure which shows the process of reducing a frequency, when the frequency of an inner side movable plate is higher than setting in the planar actuator of a two-dimensional drive system. The figure which shows the process of reducing a frequency, when the frequency of an inner side movable plate is higher than setting in the planar actuator of a two-dimensional drive system. The figure which shows the process of reducing a frequency, when the frequency of an inner side movable plate is higher than setting in the planar actuator of a two-dimensional drive system. The figure which shows the process of reducing a frequency, when the frequency of an inner side movable plate is higher than setting in the planar actuator of a two-dimensional drive system. The figure which shows the process of reducing a frequency, when the frequency of an inner side movable plate is higher than setting in the planar actuator of a two-dimensional drive system. The figure which shows the adjustment process which increases a frequency, when the frequency of an inner side movable plate is lower than setting in the planar actuator of a two-dimensional drive system. The figure which shows the adjustment process which increases a frequency, when the frequency of an inner side movable plate is lower than setting in the planar actuator of a two-dimensional drive system. The figure which shows the adjustment process which increases a frequency, when the frequency of an inner side movable plate is lower than setting in the planar actuator of a two-dimensional drive system. The figure which shows the adjustment process which increases a frequency, when the frequency of an inner side movable plate is lower than setting in the planar actuator of a two-dimensional drive system. The figure which shows the adjustment process which increases a frequency, when the frequency of an inner side movable plate is lower than setting in the planar actuator of a two-dimensional drive system. The figure which shows the process of decreasing a frequency, when the frequency of an outer movable plate is higher than setting in the planar electromagnetic actuator of a two-dimensional drive system. The figure which shows the process of decreasing a frequency, when the frequency of an outer movable plate is higher than setting in the planar electromagnetic actuator of a two-dimensional drive system. The figure which shows the process of decreasing a frequency, when the frequency of an outer movable plate is higher than setting in the planar electromagnetic actuator of a two-dimensional drive system. The figure which shows the process of increasing a frequency, when the frequency of an outer movable board is lower than setting in the planar type electromagnetic actuator of a two-dimensional drive system. The figure which shows the process of increasing a frequency, when the frequency of an outer movable board is lower than setting in the planar type electromagnetic actuator of a two-dimensional drive system. The figure which shows the process of increasing a frequency, when the frequency of an outer movable board is lower than setting in the planar type electromagnetic actuator of a two-dimensional drive system. It is a figure which shows the structure of the conventional planar type | mold actuator, (a) is front sectional drawing, (b) is a top view, (c) A bottom view. 2A and 2B are views showing a planar actuator chip, where FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. The figure which shows the manufacturing process of a planar type actuator chip.

Explanation of symbols

101 silicon substrate 102 movable plate 103 torsion bar 104 torsion bar 105 planar coil 106 mirror 107 base substrate 107a hole 107b pattern 108 wire 109 wire connection pad 110 permanent magnet 111 permanent magnet 112 yoke 113 SOI substrate 114 active layer silicon 115 intermediate layer silicon oxide Film 116 Support substrate silicon 117 Silicon oxide film 118 Coil 119 Insulating film 120 Protective film 121 Total reflection mirror 122 Metal film 123 Frequency adjustment portion 124 Silicon substrate 125 First torsion bar 126 Outer movable plate 127 Second torsion bar 128 Inner movable plate 129 Coil 130 Frequency adjustment portion 131 Frame portion 132 Wire connection pad 133 Lead wire 134 Insulating film 135 Protective film 136 Total reflection mirror

Claims (4)

A substrate, a movable plate and the movable plate formed integrally with the torsion bar to be rotatably supported to the substrate, in the manufacturing method of the movable plate rotates to Help Leena actuator,
After measuring the resonance frequency of the movable plate, when the measurement frequency is different from the desired resonance frequency, either the movable plate or the torsion bar is processed by film formation, and the other is processed by etching. Thus , the planar type actuator manufacturing method is characterized in that the resonance frequency of the movable plate is adjusted to the desired resonance frequency . When a mirror is formed on one surface of the movable plate, a frequency adjustment portion for frequency adjustment is provided on the other surface of the movable plate opposite to the mirror formation surface, and the film forming process is performed on the frequency adjustment portion. The method for manufacturing a planar actuator according to claim 1, wherein the etching process is performed . The movable plate is a frame-shaped outer movable plate that is pivotally supported on the semiconductor substrate by a first torsion bar, and a second torsion bar whose axial direction is orthogonal to the first torsion bar. In a manufacturing method of a planar actuator of a two-dimensional drive method, comprising a supported inner movable plate and rotating the inner movable plate and the outer movable plate,
After adjusting the resonance frequency of the inner movable plate by processing at least one of the inner movable plate and the second torsion bar , the outer movable plate is processed by processing at least one of the outer movable plate and the first torsion bar. to adjust the resonance frequency,
The processing for adjusting the resonance frequency of the inner movable plate includes forming or etching one of the inner movable plate and the second torsion bar, or forming the inner movable plate and the second torsion bar. Depositing either one and etching the other,
The processing for adjusting the resonance frequency of the outer movable plate is to form or etch one of the outer movable plate and the first torsion bar, or the outer movable plate and the first torsion bar. A method of manufacturing a planar actuator, wherein one of the films is formed and the other is etched . When forming a mirror on one surface of the inner movable plate, a frequency adjustment part for frequency adjustment is provided on the other surface of the inner movable plate opposite to the mirror forming surface, and the component is formed on the frequency adjustment part. The method for manufacturing a planar actuator according to claim 3 , wherein film processing or etching processing is performed .

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