JP2006242590A - Oscillation gyroscope sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the characteristic by suppressing the occurrence of a pyroelectric effect of a piezo-electric thin film layer by external light while keeping the small size and small thickness. <P>SOLUTION: A cover member 40 that covers each mounted component mounted to a component mounting region 16 and is combined on to a support substrate 2 fixes the entire circumference of the opening edge of the outer peripheral wall section 42 in a frame-like region 18 between a light blocking stage section 17 formed around the component mounting region 16 and the outer periphery edge, thereby blocking the external light permeating an adhesion resin 45 with the light blocking stage section 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration gyro sensor including a cantilever vibration element.

  The gyro sensor is mounted on a video camera or the like that is likely to cause a camera shake phenomenon in a recorded image due to, for example, high zoom ratio and miniaturization, and image information on an imaging substrate such as a CCD (Charge-Coupled Device). This is used in a camera shake correction mechanism that outputs a control signal for controlling the take-in position. Further, the gyro sensor is used in a virtual reality device to constitute a motion detector, and is used in a car navigation device to constitute a direction detector.

  A video camera shake correction mechanism is also provided that performs correction by matching the positional deviation itself on the time axis of the recorded image, but in general, the rotation angle of the holding state of the video camera is set. A configuration in which an actual camera shake amount is corrected using a gyro sensor that detects and outputs a corresponding angular velocity is used. In the gyro sensor, a rotating body or optical means is used as a detection mechanism, or a vibration element is used.

  The vibration-type gyro sensor includes a vibration element having a cantilever vibrator portion in which a pair of electrode layers are stacked on a main surface of a silicon material with a piezoelectric thin film layer interposed therebetween (see, for example, Patent Document 1). The vibration-type gyro sensor detects a change in angular velocity due to vibration or the like by vibrating a vibrator unit at a predetermined resonance frequency and detecting a Coriolis force generated by a change in angular velocity with a piezoelectric element and a detection electrode. The vibration-type gyro sensor has features such as a simple structure, high responsiveness by being activated in a short time, small size, and low cost.

Japanese Patent Laid-Open No. 7-113643

  By the way, in the vibration type gyro sensor, further downsizing and high performance are demanded with the reduction in size and weight of the mounted device and the improvement in multifunctional performance. In the vibration type gyro sensor, for example, various functions are achieved in combination with various sensors. However, the vibration gyro sensor is reduced in size as a whole by being mounted on one support substrate together with the various sensors. However, in the vibration type gyro sensor, each electrode of the vibration element and the terminal portion on the support substrate side are generally connected by a wire bonding method, and a space for routing the wire around the vibration element is required, which is small. It was a major factor that hindered the realization of the system.

  In the vibration-type gyro sensor, there is a problem that the cost is increased because the structure of the vibration element becomes complicated due to the influence of external vibration and the like as the size is reduced. In the vibration type gyro sensor, since the installation state is determined by the specifications of the device, it must be configured so that predetermined characteristics can be stably obtained even when used in any state.

  As described above, the vibration type gyro sensor includes a vibration element having a cantilever vibrator portion in which a pair of electrode layers are stacked on a main surface of a silicon material with a piezoelectric thin film layer such as lead zirconate titanate sandwiched therebetween. Provided. In the vibration type gyro sensor, the piezoelectric thin film layer has a characteristic of generating a voltage due to the pyroelectric effect when irradiated with light, and this pyroelectric voltage (pyroelectricity) affects the sensor output and has a detection characteristic. There is a problem of lowering.

  In a semiconductor package or the like, there is a problem that an electromotive force is generated when light hits the PN junction and the characteristics change. Therefore, the element is sealed with a light shielding resin such as an epoxy resin colored black. Stopped. In a semiconductor package or the like, the light-shielding resin body is designed to improve the characteristics by supporting the light shielding as well as mechanically protecting the element.

  On the other hand, since the vibration type gyro sensor has the vibrator portion of the movable portion, a structure in which the vibration element is sealed with a light shielding resin body as in the semiconductor package described above cannot be employed. Conventionally, in the vibration type gyro sensor, for example, the vibration element is mounted on the support substrate through an appropriate light shielding structure. However, there is a problem that the structure is complicated and the size is increased.

  In the vibration type gyro sensor, it is possible to cope with such a case that a mounting space portion is formed on a support substrate on which mounting parts such as vibration elements and electronic parts are mounted, and a light shielding cover member is combined. However, the vibration type gyro sensor can improve the efficiency of the mounting process by mounting each mounting component on the support substrate by the surface mounting method, but the assembly efficiency is improved because the light shielding cover member is assembled in a separate process. There was a problem of not being able to plan.

  The vibration type gyro sensor improves mounting efficiency by placing a light-shielding cover member on the main surface of the support substrate, for example, so as to cover each mounted component, and bonding the opening edge with adhesive resin or the like over the entire circumference. Comes to be planned. However, in the vibration type gyro sensor, since the adhesive resin generally has light transmittance, there is a problem that external light passes through the adhesive resin layer and acts on the internal vibration element. In the vibration type gyro sensor, by increasing the thickness of the adhesive resin layer in order to suppress the transmission of external light, there arises a problem that managing the filling amount of the adhesive resin becomes troublesome or large.

  Furthermore, in the vibration type gyro sensor, the demand for thinning is dealt with by reducing the size and thickness of the cover member. However, in the vibration type gyro sensor, it becomes difficult to maintain sufficient light shielding characteristics for infrared light, and the pyroelectric effect is generated in the piezoelectric thin film layer by the infrared light, and the detection characteristics are deteriorated. There was a problem.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vibration type gyro sensor that is improved in characteristics while maintaining a small size and a thin shape and suppressing generation of a pyroelectric effect of a piezoelectric thin film layer by external light.

  The vibration-type gyro sensor according to the present invention that achieves the above-described object mounts a vibration element, a circuit element, or an electronic component in a component mounting region on the main surface, and forms a frame-shaped light shielding step portion surrounding the component mounting region. Each mounted component is mounted on the main surface of the support substrate by presenting a substantially box shape in which the outer peripheral wall portion is integrally formed over the entire periphery on the outer peripheral portion of the main surface portion covering the component mounting area. And a cover member that forms a space portion and is combined. In the vibration type gyro sensor, the cover member is fixed to the frame-shaped fixing portion formed between the light shielding step portion of the main surface and the outer peripheral edge at the opening edge portion of the outer peripheral wall portion, Combined with the support substrate.

  In the vibration type gyro sensor, each mounting component is mechanically and electrically protected by a cover member combined on the main surface of the support substrate. In the vibration type gyro sensor, the cover member is assembled by a so-called surface mounting method in which the cover member is combined from the surface side on the main surface of the support substrate in the same manner as the vibration element and the electronic component. Efficiency will be improved. In the vibration type gyro sensor, even when the cover member is fixed on the main surface of the support substrate with an adhesive resin, external light transmitted through the adhesive resin layer enters the mounting area of each mounting component by the shielding step. It will be suppressed. In the vibration type gyro sensor, the fixing portion between the cover member and the support substrate is thinned to make the whole thin. In the vibration type gyro sensor, generation of pyroelectric effect of the piezoelectric thin film layer due to external light is suppressed, and detection characteristics are improved.

  According to the vibration type gyro sensor of the present invention, the cover member that covers each mounted component mounted in the component mounting region and is combined with the support substrate is between the light shielding step portion formed around the component mounting region and the outer peripheral edge. Since the opening edge portion of the outer peripheral wall portion is fixed over the entire circumference in the frame-shaped fixing portion, the entrance of external light from the fixing portion to the component mounting area is suppressed by the light shielding step portion, and the vibration element is Ensure stable and accurate operation. Therefore, according to the vibration-type gyro sensor of the present invention, it is possible to obtain a stable characteristic with high sensitivity while being thinned.

  Hereinafter, the vibration type gyro sensor 1 shown in the drawings as an embodiment of the present invention will be described in detail. As shown in FIG. 1, the vibration type gyro sensor 1 constitutes an external member by a support substrate 2 and a cover member 40 that is assembled on the main surface of the support substrate 2 and forms the component mounting space portion 3. It is mounted on a video camera and constitutes a camera shake correction mechanism. The vibration type gyro sensor 1 is used, for example, in a virtual reality device to constitute an operation detector, or is used in a car navigation device to constitute a direction detector.

  In the vibration type gyro sensor 1, for example, a ceramic substrate or a glass substrate is used as the support substrate 2, and a predetermined wiring pattern 5 having a large number of lands 4 is formed on the main surface, although details are omitted. 16 is configured. The support substrate 2 is connected to each land 4 and a pair of vibration elements 20A and 20B (details will be collectively referred to as the vibration element 20 unless otherwise described), which will be described in detail later on the component mounting region 16. The IC circuit element 6 or a large number of external ceramic capacitors and appropriate electronic components 7 are mounted.

  As will be described in detail later, an outer peripheral portion of the support substrate 2 is stepped down from the main surface over the entire periphery so as to rim the component mounting region 16, and a vertical wall formed at the stepped portion. As will be described later, the light shielding step portion 17 that shields external light incident from the joint portion of the cover member 40 to the component mounting region 16 is configured. In the support substrate 2, a frame-like thin portion continuous with the light shielding step portion 17 forms a cover portion fixing region 18 for fixing the cover member 40 to be bonded.

  In the vibration type gyro sensor 1, the vibration element 20 is formed on the basis of a silicon single crystal substrate 21 (hereinafter abbreviated as a silicon substrate 21) as will be described in detail later, and on the component mounting region 16 of the support substrate 2. Are mounted in a state shifted by 90 ° from each other. The vibration element 20 will be described in detail later. As shown in FIGS. 2 and 3, as shown in FIGS. 2 and 3, a base portion 22 formed in a slightly thick rectangular shape and a vibrator integrally projecting from one side portion of the base portion 22. Part 23.

  In the vibration element 20, the second main surface of the base 22 constituted by the second main surface of the silicon substrate 21 constitutes a mounting surface for the support substrate 2 as described later. In the vibration element 20, the first terminal portion 24 </ b> A to the fourth terminal portion 24 </ b> D (hereinafter collectively referred to as the terminal portion 24 unless otherwise described) are formed on the second main surface of the base portion 22. The first gold bumps 25A to the fourth gold bumps 25D (hereinafter collectively referred to as gold bumps 25 unless otherwise described) are formed on the terminal portions 24, respectively.

  The vibration element 20 is formed so that the terminal portions 24 correspond to the lands 4 formed on the wiring pattern 5 on the support substrate 2 side, and the opposing terminal portions 24 and the lands 4 are aligned as will be described in detail later. Then, it is combined with the support substrate 2. The vibration element 20 is mounted on the support substrate 2 by applying an ultrasonic wave to the gold bumps 25 while performing the welding process while pressing the vibration element 20 against the support substrate 2. The vibration element 20 is mounted via a gold bump 25 having a predetermined height, so that the vibrator unit 23 holds the second main surface at a predetermined height position with respect to the main surface of the support substrate 2. The

  In the resonator element 20, the vibrator portion 23 has a second principal surface constituted by the second principal surface of the silicon substrate 21, the same surface as the second principal surface of the base portion 22, and one end portion integrated with the base portion 22. And cantilevered. The vibration element 20 has a predetermined thickness as the vibrator portion 23 is stepped down from the first main surface of the base portion 22 constituted by the first main surface of the silicon substrate 21 on the first main surface side. The vibration element 20 is configured by a rectangular cantilever in which the vibrator portion 23 has a predetermined length and a cross-sectional area and is integrally formed with the base portion 22.

  In the vibrator portion 23, a reference electrode layer (first electrode layer) 26 is formed on the second main surface over substantially the entire length in the length direction, and a piezoelectric element having substantially the same length is formed on the reference electrode layer 26. A thin film layer 27 is laminated. In the vibrator portion 23, a drive electrode layer (second electrode layer) 28 having a substantially same length and a narrow width is formed on the piezoelectric thin film layer 27 so as to be laminated at the center in the width direction. A pair of detection electrodes 29R and 29L (hereinafter collectively referred to as detection electrodes 29 unless otherwise described) are laminated on the piezoelectric thin film layer 27 with the layer 28 interposed therebetween.

  As shown in FIG. 3, the reference electrode layer 26 is integrated with the second terminal portion 24 </ b> B by extending the lead 26-1 from the base end portion onto the second main surface of the base portion 22. . Similarly, in the vibration element 20, the drive electrode layer 28 is integrated with the third terminal portion 24 </ b> C via the lead 28-1. Further, in the vibration element 20, similarly, the first detection electrode 29R is integrated with the first terminal portion 24A via the lead 29R-1, and the second detection electrode 29L is fourth via the lead 29L-1. It is integrated with the terminal portion 24D.

  As described above, the vibration element 20 has the first terminal portion 24A to the fourth terminal portion 24D arranged at substantially the four corners on the second main surface of the base portion 22, but is limited to this configuration. It is not what is done. In the vibration element 20, the terminal portion 24 is formed on the base portion 22 with an appropriate position and number depending on the lead routing from each electrode layer and the fixed number or size with respect to the support substrate 2. In the vibration element 20, gold bumps 25 are formed on the respective terminal portions 24. However, as shown by a chain line in FIG. 3, a so-called dummy fifth gold that does not electrically connect to the second main surface of the base portion 22. The bump 25E may be formed. Of course, a dummy terminal part to which the fifth gold bump 25E is welded and fixed is formed on the support substrate 2 side.

  The vibration type gyro sensor 1 mounts the first vibration element 20A and the second vibration element 20B on the component mounting region 16 of the support substrate 2 as described above. In the vibration type gyro sensor 1, the first vibration element 20 </ b> A fixes the base portion 22 at one corner portion 2 </ b> C- 1 of the support substrate 2 with respect to the support substrate 2 as shown in FIG. Mount along one side edge of the direction. In the vibration type gyro sensor 1, the second vibration element 20 </ b> B fixes the base portion 22 to the support substrate 2 at the corner portion 2 </ b> C- 2 and the corner portion 2 </ b> C- 2 diagonally with respect to the support substrate 2. Mount along one side edge.

  As will be described later, the vibration type gyro sensor 1 outputs a control signal based on a vibration state caused by a camera shake detected by the vibration element 20 to constitute a camera shake correction mechanism. The vibration type gyro sensor 1 includes, for example, a drive detection circuit unit 8 shown in FIG. 4 configured by an IC circuit element 6 and an electronic component 7 connected to the vibration element 20. In the vibration type gyro sensor 1, the drive detection circuit unit 8 includes an impedance conversion circuit 9, an addition circuit 10, an oscillation circuit 11, a differential amplification circuit 12, a synchronous detection circuit unit 13, a DC amplification circuit 14, and the like. I have.

  As shown in FIG. 4, in the drive detection circuit unit 8, the impedance conversion circuit 9 and the differential amplifier circuit 12 are connected to the first detection electrode 29 </ b> R of the vibration element 20. In the drive detection circuit unit 8, the addition circuit 10 is connected to the impedance conversion circuit 9, and the oscillation circuit 11 connected to the addition circuit 10 is connected to the second detection electrode 29L. In the drive detection circuit unit 8, a synchronous detection circuit unit 13 is connected to the differential amplifier circuit 12 and the oscillation circuit 11, and a DC amplifier circuit 14 is connected to the synchronous detection circuit unit 13. The reference electrode layer 26 of the vibration element 20 is connected to the reference potential 15 on the support substrate 2 side.

  In the drive detection circuit unit 8, a self-excited oscillation circuit is configured by the vibration element 20, the impedance conversion circuit 9, the addition circuit 10, and the oscillation circuit 11, and an oscillation output Vg 0 having a predetermined frequency is output from the oscillation circuit 11 to the transducer unit 23. Is applied to cause natural vibration. The drive detection circuit unit 8 is supplied with the output Vgr from the first detection electrode 29R and the output Vgl from the second detection electrode 29L of the vibration element 20 to the impedance conversion circuit 9, and based on these inputs, the impedance conversion circuit 9 Output Vzr and Vzl to the adder circuit 10, respectively. The drive detection circuit unit 8 feeds back the addition output Vsa from the addition circuit 10 to the oscillation circuit 11 based on these inputs.

  In the drive detection circuit unit 8, the output Vgr from the first detection electrode 29R of the vibration element 20 and the output Vgl from the second detection electrode 29L are supplied to the differential amplifier circuit 12. The drive detection circuit unit 8 obtains a predetermined output Vda by the differential amplifier circuit 12 because a difference occurs between the output Vgr and the output Vgl in a state where the vibration element 20 detects a hand shake as described later. In the drive detection circuit unit 8, the output Vda from the differential amplifier circuit 12 is supplied to the synchronous detection circuit unit 13. The drive detection circuit unit 8 synchronously detects the output Vda in the synchronous detection circuit unit 13 to convert it into a DC signal Vsd, supplies it to the DC amplifier 14, and outputs a DC signal Vsd that has been subjected to predetermined DC amplification.

  The drive detection circuit unit 8 integrates after the synchronous detection circuit unit 13 full-wave rectifies the output Vda of the differential amplifier circuit 12 at the timing of the clock signal Vck output from the oscillation circuit 11 in synchronization with the drive signal. To obtain a DC signal Vsd. The drive detection circuit unit 8 amplifies the DC signal Vsd in the DC amplifier 14 as described above, detects a change in angular velocity caused by camera shake, and detects a detection signal.

  The drive detection circuit unit 8 is configured to obtain a low impedance output z3 when the impedance conversion circuit 9 is in a high impedance input z2, and adds to the impedance z1 between the first detection electrode 29R and the second detection electrode 29L. The effect of separating the impedance z4 between the inputs of the circuit 10 is achieved. In the drive detection circuit unit 8, by providing the impedance conversion circuit 9, it is possible to obtain a large output difference from the first detection electrode 29R and the second detection electrode 29L.

  In the drive detection circuit unit 8, the impedance conversion circuit 9 performs an impedance conversion function between input and output, and does not affect the magnitude of the signal. Therefore, in the drive detection circuit unit 8, the output Vgr from the first detection electrode 29R, the output Vzr on one side of the impedance conversion circuit 9, the output Vgl from the second detection electrode 29L, and the output on the other side of the impedance conversion circuit 9 Vzl is the same size. In the drive detection circuit unit 8, even if there is a difference between the output Vgr from the first detection electrode 29 </ b> R and the output Vgl from the second detection electrode 29 </ b> L due to the detection of camera shake by the vibration element 20, It is held at the output Vsa. In the drive detection circuit unit 8, even if noise may be superimposed due to, for example, switching operation or the like, the noise component superimposed on the output Vgo of the oscillation circuit functions other than the resonance frequency by the same function as the band filter in the vibration element 20. The output Vda from which the noise component has been removed is obtained from the differential amplifier circuit 12.

For example, after a large number of vibration elements 20 are formed in a lump on the basis of the silicon substrate 21 cut out so that the azimuth plane of the main surface is the (100) plane and the side azimuth plane is the (110) plane, After the cutting process, it is cut into pieces one by one. The silicon substrate 21 is subjected to a thermal oxidation process, and silicon oxide films (SiO ₂ films) 30A and 30B are formed over the entire front and back main surfaces, respectively. The silicon oxide films 30A and 30B function as protective films when the silicon substrate 21 is subjected to crystal anisotropic etching.

  Although details of the vibration element manufacturing process are omitted, the vibration element forming portions corresponding to the formation regions of the vibration elements 20 are removed from the silicon oxide film 30 </ b> A formed on the first main surface of the silicon substrate 21. A step of forming the part is performed. In the vibration element manufacturing process, a photoresist layer is formed on the entire surface of the silicon oxide film 30A of the silicon substrate 21 with, for example, a photosensitive photoresist material. In the vibration element manufacturing process, the photoresist layer is exposed and developed in a state in which the photoresist layer is masked with each vibration element forming portion as an opening. In the vibration element manufacturing process, through these steps, the photoresist layer corresponding to the vibration element forming portion is removed to form an opening that allows the silicon oxide film 30A to face outward.

  In the vibration element manufacturing process, a portion corresponding to the vibrator portion 23 of the vibration element 20 is formed on the silicon substrate 21 after performing a first etching process for removing the silicon oxide film 30A exposed to the opening. A second etching process is performed. The first etching process employs a wet etching method in which only the silicon oxide film 30A is removed in order to maintain the smoothness of the interface of the silicon substrate 21, but is not limited to this method. For example, an ion etching method or the like is used. The appropriate etching process may be used. In the first etching process, for example, an ammonium fluoride solution is used as an etchant, and the silicon oxide film 30A exposed to the opening of the photoresist layer is removed to form the opening, thereby forming the first etching of the silicon substrate 21. 1 Make the main surface face outward.

  The second etching process is a step of etching the silicon substrate 21 exposed outward from the opening of the silicon oxide film 30A to the thickness of the vibrator portion 23, and the etching rate depends on the crystal direction of the silicon substrate 21. Crystal anisotropic wet etching utilizing properties is performed. In the second etching process, for example, TMAH (tetramethylammonium hydroxide), KOH (potassium hydroxide), or EDP (ethylenediamine-pyrocatechol-water) solution is used as an etchant.

  In the second etching process, the (110) plane having a surface orientation of an angle of about 55 ° with respect to the (100) plane appears due to the characteristic that the silicon substrate 21 has a low etching resistance on the side surface relative to the first main surface. Then, a rectangular recess having a predetermined dimensional shape on the first main surface of the silicon substrate 21 is formed. In the vibration element manufacturing process, after a large number of rectangular recesses are formed on the first main surface, the remaining photoresist layer is removed from the silicon substrate 21 by etching.

  In the vibration element manufacturing process, through the above-described steps, a rectangular vibrator constituent portion that has a predetermined thickness between the bottom surface of the rectangular recess and the second main surface of the silicon substrate 21 and constitutes the vibrator section 23 is formed. Form. In the vibrating element manufacturing process, an electrode forming process is performed with the second main surface side of the vibrator constituting portion as a processed surface. The electrode forming step includes, for example, a first electrode layer constituting the reference electrode layer 26 via the silicon oxide film 30B and a piezoelectric film layer constituting the piezoelectric thin film layer 27 on the second main surface by a magnetron sputtering apparatus. A second electrode layer constituting the drive electrode layer 28 and the detection electrode 29 is laminated.

  In the piezoelectric film layer forming step, a piezoelectric material, for example, lead zirconate titanate (PZT) is sputtered over the entire surface of the first electrode layer to form a piezoelectric film layer having a predetermined thickness. In the piezoelectric film layer forming step, a crystallization heat treatment is performed by heating the piezoelectric film layer with an electric furnace. In the second electrode layer forming step, the second electrode layer is laminated and formed by sputtering platinum over the entire surface of the piezoelectric film layer 37 to form a platinum layer.

  The vibration element manufacturing process includes a driving electrode layer 28 having a predetermined shape, a pair of detection electrodes 29, and a second electrode layer patterning process in which a patterning process is performed on the second electrode layer formed in the uppermost layer through the above-described processes. Form. The drive electrode layer 28 is an electrode to which a predetermined drive voltage for driving the vibrator unit 23 is applied as described above, and a longitudinal direction with a predetermined width in the center region in the width direction of the vibrator unit 23. Is formed over almost the entire area. The detection electrodes 29 are electrodes that detect the Coriolis force generated in the vibrator portion 23, and are formed in parallel while being insulated from each other over almost the entire region in the length direction, located on both sides of the drive electrode layer 28. The

  In the second electrode layer patterning step, a photolithographic process is performed on the second electrode layer to form a resist layer at a corresponding portion of the drive electrode layer 28 and the detection electrode 29, and an unnecessary portion of the second electrode layer is formed, for example, The drive electrode layer 28 and the detection electrode 29 are formed on the piezoelectric film layer through a process such as cleaning the resist layer after removal by an ion etching method or the like. The vibration element manufacturing process is not limited to the process described above, and the drive electrode layer 28 and the detection electrode 29 may be formed using an appropriate conductive layer forming process employed in the semiconductor process. It is.

  In the second electrode layer patterning step, a similar patterning process is performed on the conductor layer formed integrally with the second electrode layer in the formation region of the base portion 22, thereby forming the first detection electrode on the formation portion of the base portion 22. A lead 29R-1 that is integrally drawn with a predetermined width from 29R and a first terminal portion 24A that is integrated at the tip thereof are formed. Similarly, in the second electrode layer patterning step, a lead 29L-1 that is integrally pulled out from the second detection electrode 29L with a predetermined width and a fourth terminal portion 24D that is integrated at the tip thereof, A lead 28-1 that is integrally pulled out from the drive electrode layer 28 with a predetermined width and a third terminal portion 24C that is integrated at the tip thereof are formed.

  In the vibration element manufacturing process, the piezoelectric thin film layer 27 is formed by performing a patterning process on the piezoelectric film layer while leaving a portion having a larger area than the drive electrode layer 28 and the detection electrode 29 described above. The piezoelectric thin film layer 27 is slightly smaller than the width of the vibrator portion 23 and is formed from the proximal end portion to the vicinity of the distal end of the distal end portion. In the piezoelectric film layer patterning process, a photolithographic process is performed on the piezoelectric film layer to form a resist layer at a corresponding portion of the piezoelectric thin film layer 27, and an unnecessary portion of the piezoelectric film layer is removed by, for example, a wet etching method. The piezoelectric thin film layer 27 is formed through a process such as cleaning the resist layer.

  In the vibration element manufacturing process, the reference electrode layer 26 is formed by a first electrode layer patterning process in which a patterning process is performed on the first electrode layer. The reference electrode layer 26 is formed on the second main surface of the vibrator portion 23 with a width slightly smaller than the width and larger than the piezoelectric thin film layer 27. In the first electrode layer patterning step, a patterning process is simultaneously performed on the first electrode layer exposed by removing the piezoelectric film layer that has covered the formation portion of the base portion 22 in the piezoelectric film layer patterning step. Applied. In the first electrode layer patterning step, the lead 26-1 that is integrally drawn with a predetermined width from the reference electrode layer 26 on the formation site of the base 22 and the second terminal portion 24B integrated at the tip thereof. Form.

  In the vibration element manufacturing process, since the vibration element 20 is surface-mounted on the support substrate 2 as described above, the gold bumps 25 are formed on the respective terminal portions 24. In the gold bump forming step, a plating resist layer is formed over the entire second main surface of the base portion 22 where the terminal portion 24 is formed through the above-described steps, and a photographic process is performed on the plating resist layer. Thereby, the opening part which makes each terminal part 24 face outward is formed.

  In the gold bump forming step, the gold bump 25 integrated with the terminal portion 24 is formed by performing a gold plating process using the terminal portion 24 exposed from the opening as an electrode. The gold plating process is performed, for example, by a lift-off method in which a gold plating layer is grown from a plating resist layer to a predetermined height, so that the gold bump 25 having a predetermined height is formed. In the gold bump forming step, so-called dummy bumps 25E are simultaneously formed on the base 22 as necessary.

  In the vibration element manufacturing process, a grooving process by, for example, a reactive ion etching method is performed on the silicon substrate 21 so that the outer peripheral portion of the vibrator portion 23 forms a vertical surface. In the grooving process, an etching apparatus equipped with inductively coupled plasma (ICP) is used, and the etching process and a protective film forming process for protecting the outer peripheral wall at the etched location are repeated. Reactive ion etching method is used.

  In the vibration element manufacturing process, the outer shape of the vibrator portion 23 of each vibration element 20 is formed by forming a U-shaped groove penetrating the silicon substrate 21 by the above-described groove cutting process. In the vibration element manufacturing process, each vibration element 20 is cut by cutting the base 22 with a diamond cutter or the like, for example. About a cutting process, after forming a cutting groove with a diamond cutter, the silicon substrate 21 is folded and divided. In the cutting step, cutting may be performed using a surface orientation of the silicon substrate 21 by a grindstone or grinding.

  The vibration element 20 manufactured through the above steps is surface-mounted on the component mounting region 16 of the support substrate 2 with the second main surface of the base portion 22 as a mounting surface. In the vibration element 20, the gold bumps 25 provided on the terminal portions 24 are aligned with the opposing lands 4 on the support substrate 2 side. The vibration element 20 is mounted on the component mounting region 16 of the support substrate 2 by welding the gold bumps 25 to which the ultrasonic waves are applied while being pressed against the support substrate 2 to the opposing lands 4.

  After mounting the IC circuit element 6 and the electronic component 7 together with the vibration element 20 on the component mounting area 16 on the support substrate 2, the component mounting space portion 3 is formed from above as shown by the arrow in FIG. 40 is assembled to complete the vibration type gyro sensor 1. The cover member 40 protects mounting components such as the vibration element 20 from an external mechanical load and maintains insulation from the outside. The cover member 40 preferably has a function of blocking external noise, and is formed of a thin metal plate such as a SUS material or an aluminum material. As will be described later, the cover member 40 also has a light shielding function that shields external light applied to the vibration type gyro sensor 1 so that the pyroelectric effect does not occur in the piezoelectric thin film layer 27 of the vibration element 20. .

  As shown in FIG. 1, the cover member 40 has a main surface portion 41 having an outer dimension sufficient to cover the component mounting region 16 of the support substrate 2, and an outer peripheral portion of the main surface portion 41 is integrally bent over the entire periphery. The entire outer peripheral wall portion 42 is formed in a box shape. In the cover member 40, the outer peripheral wall portion 42 is formed with a height sufficient to allow the vibrator portion 23 of the vibration element 20 to perform a vibration operation in the component mounting space portion 3. The cover member 40 is integrally formed with an outer peripheral flange portion 43 that is bent in the horizontal direction over the entire periphery at the opening edge of the outer peripheral wall portion 42. The outer peripheral flange portion 43 is slightly smaller in width than the cover member fixing region 18 formed on the outer peripheral portion of the support substrate 2. In addition, although not shown in figure, the cover member 40 forms an earth | ground convex part in a part of outer periphery flange part 43, and is ground-connected in the state in which the vibration type gyro sensor 1 was mounted in the apparatus.

  By the way, the cover member 40 is formed of a thin metal plate as described above, thereby reducing the thickness and weight of the vibration gyro sensor 1. For this reason, the cover member 40 has a possibility that the light shielding function with respect to the light component of the infrared light of the external light is deteriorated and the above-described light shielding function cannot be sufficiently achieved. The cover member 40 is formed with a light shielding layer 44 on the entire surface of the main surface portion 41 and the outer peripheral wall portion 42 by applying, for example, a well-known infrared absorbing paint that absorbs light having an infrared wavelength. The light shielding layer 44 shields infrared radiation into the component mounting space 3 through the cover member 40 so that the vibration element 20 performs a stable detection operation.

  In the cover member 40, the light shielding layer 44 made of infrared absorbing paint is formed on the surfaces of the main surface portion 41 and the outer peripheral wall portion 42. For example, the light shielding layer 44 is formed on the entire front and back main surfaces by dipping in the infrared absorbing paint. It may be formed. The cover member 40 may be formed with the light shielding layer 44 by performing an appropriate surface treatment according to the material. The light shielding layer 44 is formed by, for example, a black chrome plating process, a black dyeing process performed on an iron-based material, or a black anodized (registered trademark) process performed on an aluminum-based material.

  The cover member 40 configured as described above covers each mounted component mounted on the component mounting region 16 by the main surface portion 41, and the outer peripheral flange portion 43 formed integrally with the outer peripheral wall portion 42 is fixed to the cover member. Overlaid on the region 18 over the entire region, it is combined with the support substrate 2. As shown in FIG. 5, the cover member 40 is covered with the cover resin fixing region 18 and cured by an adhesive resin 45 so that the outer peripheral flange portion 43 is overlapped with the cover member fixing region 18 over the entire periphery. Fixed.

  In the vibration type gyro sensor 1, the component mounting space portion 3 is configured as a light shielding space portion by combining the support member 2 with the cover member 40 subjected to the light shielding treatment as described above. However, since the vibration type gyro sensor 1 joins the outer peripheral flange 43 of the cover member 40 with the adhesive resin 45 on the cover member fixing region 18 of the support substrate 2, external light passes through the adhesive resin 45 to mount the component. There is a risk of entering the inside of the space 3. In the vibration type gyro sensor 1, external light transmitted through the adhesive resin 45 is shielded by the light shielding step 17.

  As described above, the vibration-type gyro sensor 1 includes the light shielding step portion 17 formed of a substantially vertical wall by forming the cover member fixing region 18 that is stepped down on the outer peripheral portion of the support substrate 2 so as to surround the component mounting region 16. The cover member 20 is fixed on the outer peripheral side of the light shielding step portion 17. In the vibration type gyro sensor 1, as shown by the arrow in FIG. 5, the external light from the side is bonded to the adhesive resin 45 from the gap between the cover member fixing region 18 of the support substrate 2 and the outer peripheral flange portion 43 of the cover member 40. And attempts to enter the component mounting space 3.

  In the vibration type gyro sensor 1, external light from the side that has passed through the adhesive resin 45 that joins the cover member 40 strikes the light shielding step portion 17, thereby preventing entry into the component mounting space portion 3. The component mounting space 3 is held as a light shielding space. Therefore, in the vibration type gyro sensor 1, the generation of the pyroelectric effect in the piezoelectric thin film layer 27 of the vibration element 20 due to the light irradiation is suppressed, the characteristic deterioration is prevented, and the stable detection operation is performed.

  In the vibration type gyro sensor 1, the assembly process can be rationalized by allowing the cover member 40 to be assembled to the support substrate 2 from the surface side in the same manner as the vibration element 20 and the like. In the vibration type gyro sensor 1, the cover member 40 is fixed to the support substrate 2 at a portion where the outer peripheral flange portion 43 is stepped down from the main surface, so that the thickness can be reduced. In the vibration type gyro sensor 1, the flow of the adhesive resin 45 applied to the cover member fixing region 18 to the component mounting region 16 by the light shielding step portion 17 is prevented, and the filling amount management of the adhesive resin 45 is also simplified.

  The cover member fixing structure 50 shown in FIG. 6 as the second embodiment is located between the outer peripheral portion and the outer peripheral edge of the component mounting region 16 of the support substrate 2 and extends over the entire periphery of the component mounting region 16. It has a feature in the structure in which the surrounding frame-like cover fitting groove 51 is formed. The cover member fixing structure 50 has the same configuration and operation as those of the first cover member fixing structure described above, and a description thereof will be omitted.

  The second cover member fixing structure 50 has a frame in which the cover fitting groove 51 is opened in the main surface of the support substrate 2 and has a slightly larger opening width than the thickness of the opening edge 42-1 of the outer peripheral wall portion 42 of the cover member 40. It consists of a groove. The cover fitting groove 51 is a state in which the opening edge 42-1 is fitted to the support substrate 2 and the cover member 40 is combined, and its inner peripheral wall constitutes a light shielding step portion 52, and external light to the inside. Prevent radiation.

  That is, in the second cover member fixing structure 50, the cover member 40 covers the component mounting region 16 with the main surface portion 41 from the surface side of the support substrate 2 and covers the opening edge 42-1 of the outer peripheral wall portion 42 over the entire area. It is fitted and combined in the cover fitting groove 51. In the second cover member fixing structure 50, the opening edge 42-1 of the cover member 40 is entirely covered with the cover fitting groove 51 by the adhesive resin 45 filled and cured in the cover fitting groove 51. Secure to. Also in the second cover member fixing structure 50, as shown by the arrows in FIG. 6, external light from the side is adhered to the adhesive resin from the gap between the inner wall of the cover fitting groove 51 and the opening edge 42-1 of the cover member 40. An attempt is made to enter the component mounting space 3 through 45.

  In the second cover member fixing structure 50, the external light from the side that has passed through the adhesive resin 45 that joins the cover member 40 strikes the light shielding stepped portion 52 constituted by the inner wall of the cover fitting groove 51. Thus, entry into the component mounting space 3 is prevented, and the component mounting space 3 is held as a light shielding space. Therefore, the second cover member fixing structure 50 suppresses the generation of the pyroelectric effect in the piezoelectric thin film layer 27 of the vibration element 20 due to light irradiation to prevent the characteristic deterioration, and the vibration type gyro sensor 1 performs a stable detection operation. To do.

  The second cover member fixing structure 50 also allows the assembly process to be rationalized by allowing the cover member 40 to be assembled to the support substrate 2 from the surface side in the same manner as the vibration element 20 and the like. In the second cover member fixing structure 50, the cover member 40 is fitted into the cover fitting groove 51 formed on the main surface of the opening edge 42-1 of the outer peripheral flange portion 43 with respect to the support substrate 2, and the adhesive resin 45. Since it is fixed by this, the thickness can be reduced. The cover member 40 may be formed with the outer peripheral flange portion 43 described above at the opening edge 42-1, and in this case, the cover fitting groove 51 has a groove width slightly larger than the width of the outer peripheral flange portion 43. To be formed.

  The cover member fixing structure 60 shown in FIG. 7 as the third embodiment is located between the outer peripheral portion and the outer peripheral edge of the component mounting region 16 of the support substrate 2, and the component mounting region 16 is formed on the main surface. It has a feature in a configuration in which a frame-shaped light-shielding convex portion 61 surrounding the entire circumference is integrally formed. The cover member fixing structure 60 is the same as the first cover member fixing structure and the second cover member fixing structure described above, and the description thereof is omitted.

  In the third cover member fixing structure 60, the light-shielding convex portion 61 is composed of a rib-shaped convex portion whose height is slightly smaller than the maximum height of each mounted component mounted on the support substrate 2, and the outer peripheral side surface is substantially the same. By being a vertical wall, the light shielding step 62 is formed to prevent the outside light from being emitted inside. In the second cover member fixing structure 60, the frame-shaped region between the light shielding convex portion 61 and the outer peripheral edge fixes the outer peripheral flange portion 43 of the cover member 40 on the main surface thereof with the adhesive resin 45. 63.

  Also in the third cover member fixing structure 60, external light from the side passes through the adhesive resin 45 from the gap between the cover member fixing region 63 and the outer peripheral flange portion 43 of the cover member 40, and the component mounting space portion 3. Try to enter inside. The third cover member fixing structure 60 prevents the external light from the side that has passed through the adhesive resin 45 that joins the cover member 40 from hitting the light shielding step portion 62, thereby preventing entry into the component mounting space portion 3. The component mounting space 3 is held as a light shielding space. Therefore, the third cover member fixing structure 60 suppresses the generation of the pyroelectric effect in the piezoelectric thin film layer 27 of the vibration element 20 due to light irradiation to prevent the characteristic deterioration, and the vibration type gyro sensor 1 performs a stable detection operation. To do.

  The third cover member fixing structure 60 also allows the assembly process to be rationalized by allowing the cover member 40 to be assembled to the support substrate 2 from the surface side in the same manner as the vibration element 20 and the like. The third cover member fixing structure 60 makes it easy to manage the filling amount of the adhesive resin 45 by preventing the adhesive resin 45 applied to the cover member fixing region 63 from flowing into the component mounting region 16 by the light shielding convex portion 61. Become.

It is the principal part perspective view which removed and showed the cover member about the vibration type gyro sensor shown as embodiment. It is principal part sectional drawing of a vibration type gyro sensor. It is a principal part bottom view of a vibration element. It is a circuit block diagram of a vibration type gyro sensor. It is principal part sectional drawing which shows the fixing structure of a cover member. It is principal part sectional drawing of the fixing structure of the cover member shown as 2nd Embodiment. It is principal part sectional drawing of the fixing structure of the cover member shown as 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibration type gyro sensor, 2 Support substrate, 3 Component mounting space part, 4 Terminal part, 5 Wiring pattern, 6 IC circuit element, 7 Electronic component, 16 Component mounting area, 17 Light shielding step part, 18 Cover member fixing area, 20 Vibrating element, 21 Silicon substrate, 22 Base part, 23 Vibrating part, 26 Reference electrode layer, 27 Piezoelectric thin film layer, 28 Drive electrode layer, 29 Detection electrode, 40 Cover member, 41 Main surface part, 42 Outer peripheral wall part, 43 Outer peripheral flange Part, 44 light shielding layer, 45 adhesive resin, 50 cover member fixing structure, 51 cover fitting groove, 52 light shielding step part, 60 cover member fixing structure, 61 light shielding step part, 63 cover member fixing region

Claims (6)

Mounting a vibration element, a circuit element, or an electronic component in a component mounting region on the main surface, and a support substrate having a frame-shaped light shielding step portion formed around the component mounting region;
The outer peripheral portion of the main surface covering the mounting area has a substantially box shape with an outer peripheral wall formed integrally over the entire periphery, and the mounting space portion of each mounting component is configured on the main surface of the support substrate. And a cover member combined together,
The support member is fixed to the frame-shaped fixing portion formed between the light shielding step portion and the outer peripheral edge of the main surface at the opening edge portion of the outer peripheral wall portion, thereby supporting the support member. A vibration type gyro sensor characterized by being combined with a substrate. The fixing portion is constituted by a stepped portion formed on the main surface of the support substrate so as to surround the component mounting region,
2. The vibration type gyro sensor according to claim 1, wherein a step at the stepped portion constitutes the light shielding step. The fixing portion is formed on a main surface of the support substrate so as to surround the component mounting region, and is configured by a frame-like fitting groove that fits an opening edge of an outer peripheral wall portion of the cover member.
2. The vibration gyro sensor according to claim 1, wherein an inner peripheral wall of the fitting groove constitutes the light shielding step portion.   2. The vibration type gyro sensor according to claim 1, wherein the light shielding step portion is configured by a frame-like convex portion that stands integrally on the main surface of the support substrate so as to surround the component mounting region. .   2. The vibration type gyro sensor according to claim 1, wherein the cover member is formed of a metal material that magnetically shields each mounted component. 2. The vibration type gyro sensor according to claim 1, wherein the cover member has a light shielding layer formed at least over the entire surface.

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