JP2008261839A - Manufacturing method of acceleration sensing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an acceleration sensing unit which is suitable for mass production, can reduce manufacturing cost while maintaining characteristics of the acceleration sensing unit. <P>SOLUTION: The manufacturing method of the acceleration sensing unit includes a process for providing a stress sensing element substrate 40 having a plurality of stress sensing elements 41' coupled by element supporting pieces 43, a process for providing an element support substrate 50 having a plurality of element supporting members 51 coupled by supporting pieces 53, a process for coating adhesive on surfaces of respective fixing members 5 and movable members 20 and superimposing the element supporting substrate 50 and the stress sensing element substrate 40 in order to connect fixing ends 44 of the respective stress sensing elements 41' to the fixing members 5 for structuring the respective element supporting members 51 and the movable members 20, and a process for curing the adhesive and cutting the element supporting pieces 43 and the supporting pieces 53. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an acceleration detection unit, and in particular, an acceleration in which a stress sensitive element and an element support member that supports the stress sensitive element and deforms by applying stress are made of the same piezoelectric material and are etched using an etching technique. The present invention relates to a method for manufacturing a detection unit.

  Conventionally, acceleration sensors have been widely used from automobiles, aircraft, and rockets to monitoring abnormal vibrations of various plants. Patent Document 1 discloses a beam structure of an acceleration sensor as shown in the perspective view of FIG. In FIG. 14, reference numeral 90 denotes a crystal double tuning fork vibrator having two vibration beams 91, 92 denotes a bonding portion of the crystal double tuning fork vibrator 90, and 100 denotes a beam made of the same crystal as the crystal double tuning fork vibrator 90. . Then, a protrusion 110 is formed integrally with the beam 100 in which only the thickness of the portion of the beam 100 in contact with the bonding portion 92 of the crystal double tuning fork vibrator 90 is thicker than the thickness of the other portion, and the protrusion 110 And the bonding portion 92 of the double tuning fork vibrator are bonded and fixed with an adhesive or the like. Furthermore, a weight 120 is provided at the free end of the beam 100, and one end facing the weight 120 is fixed to the base 130.

When the base 130 of the acceleration sensor configured as shown in FIG. 14 is fixed to the object to be measured and acceleration is applied in the direction of the arrow, the weight 120 deflects the beam 100, and the crystal double tuning fork vibrator 90 fixed to the beam 100 includes The frequency changes under compressive or tensile stress. That is, the sensor measures the magnitude of acceleration from the amount of change in frequency. By forming the protrusion 110 on the beam 100, the magnitude of the stress applied to the crystal double tuning fork vibrator 90 is increased as compared with the case where there is no protrusion 110, so that the plate thickness of the beam 100 is not reduced. In addition, it is disclosed that a highly sensitive acceleration sensor can be configured without increasing the mass of the weight 120.
JP-A-2-248866

  However, in the acceleration sensor described in Patent Document 1, the weight is at the end of the beam, and deformation of the beam due to acceleration is likely to occur in the vicinity of the fixed portion, so that the crystal double tuning fork vibrator is not sufficiently applied. In addition, since the thickness of the beam is uniform, stress due to acceleration is easily dispersed. For this reason, there is a problem that deformation is difficult to occur at a small acceleration and measurement accuracy of the small acceleration is insufficient, and that mass productivity is poor because each member is individually formed.

The method for manufacturing an acceleration detection unit of the present invention is integrated with a fixed member, an element support member having a movable member supported by the fixed member with a beam, a stress sensitive portion, and both ends of the stress sensitive portion. A stress sensitive element having a fixed end, and the beam has a flexibility that can be deformed to displace the movable member along an acceleration detection axis direction when an acceleration is applied to the movable member. The stress-sensitive element is a method of manufacturing an acceleration detection unit having a configuration in which both fixed ends are supported by the fixed member and the movable member, respectively, and is connected by a support piece and A step of preparing an element support substrate having a plurality of the element support members arranged in a plane and a stress sensitive element substrate having a plurality of stress sensitive elements connected by an element support piece and arranged in a plane are prepared. A step of superimposing the element support substrate and the stress sensitive element substrate on the fixed member and the movable member so that a fixed end of each stress sensitive element is superimposed on the fixed member and the movable member, and the fixed member and the movable member The method includes a step of fixing the fixed end on the top, and a step of cutting the element support piece and the support piece.
As described above, by adopting the method of manufacturing the acceleration detection unit, it is possible to measure a small acceleration with sufficient accuracy, good temperature characteristics, excellent mass productivity, and manufacturing a large amount of acceleration detection units at a low cost. There is an effect that can be.

The method for manufacturing an acceleration detection unit of the present invention is characterized in that the support piece, the element, and the support piece are overlapped in the superimposing step.
By adopting the method for manufacturing the acceleration detection unit as described above, the element support piece and the support piece are formed sufficiently thin compared to the dimensions of the stress sensitive element and the element support member, and a cutting machine such as dicing is used. In addition, since the element support piece and the remaining piece of the support piece can be reduced by cutting off, there is an advantage that a more accurate acceleration detection unit can be manufactured at low cost.

Also, the method of manufacturing the acceleration detection unit of the present invention includes a fixed member, an element support member including a movable member supported by the fixed member by a beam, a stress sensitive portion, and both ends of the stress sensitive portion. A stress sensitive element having a fixed end, and the beam is deformable so as to displace the movable member along an acceleration detection axis direction when acceleration is applied to the movable member. The stress-sensitive element is a method of manufacturing an acceleration detection unit having a structure in which both fixed ends are supported by the fixed member and the movable member, respectively, and is connected by a support piece. And a step of preparing an element support substrate having a plurality of element support members arranged in a planar shape, and a weight member support substrate having a plurality of weight members connected in a planar shape and connected by weight member support pieces. Small A step of preparing at least one sheet, a step of preparing a stress-sensitive element substrate having a plurality of stress-sensitive elements connected in a planar shape by element support pieces, and connecting the weight member to at least the movable member In order to do so, the step of superposing the element support substrate and the weight member support substrate to form a substrate laminate, the step of cutting the weight member support piece, the substrate laminate and each of the stress sensitive elements In order to connect the fixed ends, the method includes a step of superimposing the substrate laminate and the stress-sensitive element substrate, and a step of cutting the element support piece and the support piece.
As described above, by adopting the manufacturing method of the acceleration detection unit, the weight member support piece, the element support piece, and the support piece are formed sufficiently thin as compared with the dimensions of the weight member, the stress sensitive element, and the element support member. Since the weight member support piece, the element support piece, and the support piece are cut sequentially by cutting off, each remaining piece can be reduced and the dimensional accuracy of the acceleration detection unit can be improved. There is an advantage that a large number of units can be manufactured at low cost.

Also, the method of manufacturing the acceleration detection unit of the present invention includes a fixed member, an element support member including a movable member supported by the fixed member by a beam, a stress sensitive portion, and both ends of the stress sensitive portion. A stress sensitive element having a fixed end, and the beam is deformable so as to displace the movable member along an acceleration detection axis direction when acceleration is applied to the movable member. The stress-sensitive element is a method of manufacturing an acceleration detection unit having a structure in which both fixed ends are supported by the fixed member and the movable member, respectively, and is connected by a support piece. And a step of preparing an element supporting substrate having a plurality of element supporting members arranged in a plane, and a stress sensitive element substrate having a plurality of stress sensitive elements connected in an element supporting piece and arranged in a plane. for A step of preparing at least one weight member support substrate having a plurality of weight members connected in a planar manner and connected by a weight member support piece, and connecting the weight member to at least the movable member A step of forming a substrate laminate by superimposing the element support substrate and the weight member support substrate, and connecting the substrate laminate and a fixed end of each of the stress sensitive elements. And the step of superposing the stress-sensitive element substrate, and the step of cutting the support piece, the weight member support piece, and the element support piece.
As described above, by adopting the manufacturing method of the acceleration detection unit, the weight member support piece, the element support piece, and the support piece are formed sufficiently thin as compared with the dimensions of the weight member, the stress sensitive element, and the element support member. In addition, since each support piece can be collectively cut by folding, there is an advantage that an acceleration detecting unit with high dimensional accuracy can be efficiently manufactured in large quantities at low cost.

Moreover, the manufacturing method of the acceleration detection unit of this invention is characterized by the said support piece, the said element support piece, and the said weight support piece being provided with the recess.
By adopting the manufacturing method of the acceleration detection unit as described above, the weight member support piece, the element support piece, and the support piece are provided with easy-to-break parts (grooves), respectively. In addition, the support pieces can be easily folded and cut, and the support pieces can be cut almost without leaving the remaining pieces, so that the dimensional accuracy of the acceleration detection unit is improved and the measurement accuracy of the detection unit is improved. .

Further, in the method for manufacturing the acceleration detection unit of the present invention, the recess provided in the support piece is a groove formed along the thickness direction of the stress sensitive element substrate, and the element support piece and the weight support piece The recess provided in is a groove extending in the depth direction of the recess provided in the support piece.
By adopting the method for manufacturing the acceleration detection unit as described above, the weight member support piece, the element support piece, and the support piece are provided with recesses along the direction of folding, respectively. Since it can be easily cut from the place and can be cut without substantially leaving the remaining pieces of the respective support pieces, there is an effect that the dimensional accuracy of the acceleration detection unit is improved and the measurement accuracy of the detection unit is improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a configuration of an acceleration detection unit 1 according to the present invention. The acceleration detection unit 1 includes a fixed member 5 that is fixedly supported by a fixed portion (not shown) so as not to be displaced by application of acceleration, and a movable member that is supported in a state in which the fixed member 5 can be displaced by a beam 10. 20 and a stress sensitive element 30 having fixed ends 32 and 33 integrated at both ends of the stress sensitive part 34 and the stress sensitive part. The beam 10 is configured to have a flexibility that can be deformed so as to displace the movable member 20 along the acceleration detection axis direction when an acceleration in the acceleration detection axis direction (Z-axis direction) is applied to the movable member 20. Has been.
In the stress sensitive element 30, one fixed end 32 is supported on the upper surface of the fixed member 5, and the other fixed end 33 is supported on the upper surface of the movable member 20, and is fixed (supported) with an adhesive. The element support member 6 including the fixed member 5, the movable member 20, and the beam 10 is made of the same material as that of the stress sensitive element 30. Furthermore, it is desirable that the element support member 6 and the stress sensitive element 30 are made of the same material (the same piezoelectric material).

As the piezoelectric material, it is desirable to use a quartz crystal that has stable quality, good frequency-temperature characteristics, is suitable for mass production, and is inexpensive. That is, the element support member 6 and the stress sensitive element 30 are preferably made of the same material (quartz). Furthermore, it is not only the coincidence of the materials using the same material but also the same crystal material in which the respective cutting orientations (cut angles) coincide with the crystal axis (fixed to the crystal crystal axes of the fixed ends 32 and 33) The member 5 and the crystal crystal axis of the movable member 20 may coincide with each other). By making the cutting orientations coincide, the linear expansion coefficients of the element support member 6 and the stress sensitive element 30 become the same, and even if the ambient temperature of the stress sensing unit 1 changes, the element support member 6 and the stress sensitive element 30 are not connected. Can be minimized.
Therefore, an acceleration detection unit having high reliability and excellent acceleration detection capability with respect to environmental temperature changes can be configured.
The beam 10 connecting the fixed member 5 and the movable member 20 is configured such that the thickness gradually decreases from both ends of the beam 10 toward the central portion, and the thickness of the central portion is minimized. That is, as shown in FIG. 1, the central portion of the lower surface of the beam 10 is processed so as to be symmetrical in the Z-axis direction and to be semicircular or parabolic in the depth direction (Y-axis direction).

  The acceleration detection unit 2 shown in FIG. 2 improves the structure of the beam 10 of the acceleration detection unit 1 shown in FIG. 1 to be a beam 11, and the + direction of the acceleration detection axis direction (Z axis direction) (the arrow direction of the Z axis) ) Even when a certain amount of acceleration (acceleration in the direction of the arrow on the Z axis is + α) is applied in the negative direction (the direction opposite to the direction of the arrow on the Z axis) This is a beam structure in which the deflection of the beam 11 is equal even when the acceleration in the arrow direction of the Z-axis is positive and −α acceleration is applied. Like the beam 11 shown in FIG. 2, the upper and lower surfaces of the central portion are processed symmetrically in the X and Z axis directions and hyperbolic in the depth direction (Y axis direction). Or you may process so that thickness may decrease gradually in the shape of a step toward the center part from the both ends of a beam.

As shown in FIGS. 1 and 2, the thickness of the central portion of the beam is gradually reduced to a semicircular, parabolic or hyperbolic shape, or the thickness of the beam is stepped from both ends toward the central portion. The beam (10, 11, etc.) is bent at the thinnest part at the center of the beam when acceleration is applied to the movable member 20 in the acceleration detection axis direction. To be displaced in the direction of the acceleration detection axis. The side surface of the beam (the surface viewed from the Y-axis direction) is symmetrical with respect to the X and Z axes, for example, a beam like the beam 11 shown in FIG. This is a desirable shape because it bends uniformly regardless of the direction of positive (reverse direction is negative).
The beams 10 and 11 have shapes and dimensions that prevent displacement of the movable member 20 in the depth direction (Y direction) orthogonal to the acceleration detection axis direction (Z axis direction). The dimension in the depth direction is formed to be longer than the dimension of the width of the beams 10 and 11 in the acceleration detection axis direction (Z-axis direction). This is to prevent the movable member 20 from being displaced in directions other than the acceleration detection axis direction and to detect acceleration only in the acceleration detection axis direction.

As shown in FIGS. 1 and 2, the upper surface 5a of the fixed member 5 in the element support members 6 and 7 and the upper surface 20a of the movable member 20 arranged to face each other are parallel to the X-axis direction and are at the same level. It is comprised so that. The fixed end 32 of the stress sensitive element 30 is bonded and fixed to the upper surface 5a of the fixed member 5 and the fixed end 33 is bonded and fixed to the upper surface 20a of the movable member 20 with an adhesive. The stress sensitive part 34 is configured not to be hung on the upper surface 5a of the fixed member 5 and the upper surface 20a of the movable member 20 so as not to hinder the vibration of the stress sensitive element 30.
As shown in FIGS. 1 and 2, the stress sensitive element 30 includes two fixed ends 32 and 33, and a stress sensitive portion 34 formed of a piezoelectric substrate having two vibration beams connecting the fixed ends 32 and 33. And an excitation electrode formed on the vibration region of the piezoelectric substrate. In the embodiment of the acceleration detection unit 1 shown in FIG. 1, an example using a double tuning fork type crystal vibrating element is shown. The double tuning fork type quartz vibrating element has good sensitivity to extension / compression stress, and has excellent decomposition ability, so that a slight change in acceleration can be known. Further, the frequency temperature characteristic exhibited by the double tuning fork type crystal resonator element is an upwardly convex quadratic curve, and each parameter is set so that the apex temperature becomes room temperature (25 ° C.).

The resonance frequency f _F when the external force F is applied to the two vibrating beams of the double tuning fork type quartz vibrating element is as follows.
f _F = f ₀ (1- (KL ² F) / (2EI)) ^1/2 (1)
Here, f ₀ is the resonance frequency of the double tuning fork type quartz vibrating element when there is no external force, K is a constant according to the fundamental mode (= 0.0458), L is the length of the vibrating beam, E is the longitudinal elastic constant, I Is the moment of inertia of the cross section. Second moment I are from I = dw ^3/12, the equation (1) can be modified as follows. Here, d is the thickness of the vibration beam, and w is the width.
f _F = f ₀ (1−S _F σ) ^1/2 (2)
However, the stress sensitivity _SF and the stress σ are respectively expressed by the following equations.
S _F = 12 (K / E) (L / w) ² (3)
σ = F / (2A) (4)
Here, A is the sectional area (= w · d) of the vibration beam. From the above, when the force F acting on the double tuning fork vibrator is negative in the compression direction and positive in the extension direction (tensile direction), the relationship between the force F and the resonance frequency f _F is that the force F is a compression force and the resonance frequency. f _F decreases and increases with stretching (tensile) force. The stress sensitivity S _F is proportional to the square of the vibration beam L / w. Further, the relationship between the stress and the apex temperature has a characteristic that the apex temperature shifts to the low tone side when an extensional stress is applied to the double tuning fork type crystal vibrating element and shifts to the high temperature side when compressive stress is applied.
However, the piezoelectric vibration element is not limited to a double tuning fork type crystal resonator, and any piezoelectric vibration element whose frequency changes due to stretching / compression stress may be used.

In the acceleration detection unit 1 shown in FIG. 1, when acceleration in the + Z-axis direction (arrow direction) is applied, the movable member 20 moves from the thinnest part at the center of the beam 10 to the acceleration detection axis direction (based on the law of inertia). In this case, the stress sensitive element 30 is bent in the -Z-axis direction), and an extensional stress is applied to the stress sensitive element 30, and the resonance frequency of the stress sensitive element 30 changes from the resonance frequency at the time of no load to a high frequency. Conversely, when acceleration in the −Z direction (the direction opposite to the arrow) is applied, the movable member 20 bends from the thinnest portion at the center of the beam 10 in the acceleration detection axis direction (in this case, the + Z axis direction), and is stress sensitive. Compressive stress is applied to the element 30, and the resonance frequency of the stress sensitive element 30 changes from the resonance frequency when no load is applied to a lower frequency. The magnitude of acceleration is obtained from the amount of change in frequency.
The operation of the acceleration detection unit 2 shown in FIG. 2 when applying acceleration is the same as in FIG.

FIG. 3 is a perspective view showing the element support member 8 and the stress sensitive element 30a individually. The element support member 8 includes a fixed member 5 having a protrusion 9 formed on an upper surface 5a, a movable member 20 having a protrusion 9 formed on an upper surface 20a, and a beam 11 that couples the members 5 and 20 together. The stress sensitive element 30a includes two fixed ends 32 and 33 and a stress sensitive portion 34 formed of a piezoelectric substrate having two vibration beams connecting the fixed ends 32 and 33, and a vibration region of the piezoelectric substrate. The fixed electrodes 32 and 33 are formed with holes 38 that fit into the protrusions 9 formed on the upper surfaces of the fixed member 5 and the movable member 20. Adhesive is applied to the periphery of the protrusion 9 of the element support member 8, and the hole 38 of the stress sensitive element 30 a is fitted to the protrusion 9 (and the fixed ends 32, 33 and the fixed member 5, the movable member 20 have such a configuration. Can firmly fix the stress sensitive element 30a to the element supporting member 8 by the protrusion 9. Therefore, for example, in order to reduce the shrinkage stress (adhesive stress) of the adhesive that bonds the fixed ends 32 and 33, a silicon adhesive or the like Even when a soft adhesive is applied, the extension / compression force of the element support member 8 in the X-axis direction can be efficiently transmitted to the stress sensitive element 30a by the connection configuration of the protrusion 9 and the hole 38. is there.
Further, the protrusion 9 functions to temporarily fix the stress sensitive element 30a to the element supporting member 8 until the adhesive is cured. Such a function improves the mounting position accuracy of the stress sensitive element 30a and facilitates the assembly of the acceleration detection unit.

  FIG. 4 is a perspective view showing the configuration of the differential acceleration detection unit 3. The acceleration detection unit 3 is integrated with a fixed member 5 that is not displaced by application of acceleration, a movable member 20 that is supported by the fixed member 5 with a beam 11, a stress sensitive portion, and both ends of the stress sensitive portion. And first and second stress sensitive elements 30 and 31 each having a fixed end. The beam 11 is configured to have a flexibility that can be deformed so as to displace the movable member 20 along the acceleration detection axis direction (Z-axis direction) when acceleration is applied to the movable member 20. The first stress sensitive element 30 is on the upper surface 5a of the fixed member 5 and the upper surface 20a of the movable member 20, and the second stress sensitive element 31 is on the lower surface 5b of the fixed member 5 and the lower surface 20b of the movable member 20. Both fixed ends 32, 33 and 35, 36 (not shown) are supported and fixed, respectively. The element support member 7 including the fixed member 5, the movable member 20, and the beam 11 is made of the same material as the first and second stress sensitive elements 30 and 31.

  When an acceleration sensor is configured using the acceleration detection unit 3 shown in FIG. 4, as shown in FIG. 5, the first electrodes connected to the terminal electrodes of the first and second stress sensitive elements 30, 31 are used. It is necessary to use a circuit including the second oscillation circuits OSC1 and OSC2, a mixer MIX, a low-pass filter LPF, and a frequency-voltage converter F / V. Now, when acceleration is applied, the oscillation frequencies of the first and second oscillation circuits OSC1, OSC2 are set to f1, f2. When the frequencies f1 and f2 are mixed by the mixer MIX, frequencies (f2−f1) and (f1 + f2) are obtained, and only the difference frequency (f2−f1) can be extracted by passing through the low pass filter LPF. The difference frequency (f2-f1) is converted into a voltage by the frequency-voltage converter F / V to be output OUT, and this output voltage is converted into acceleration by an external device.

  For example, the resonance frequencies F1 and F2 when the first and second stress sensitive elements 30 and 31 are not loaded are both set to 40 kHz. −Acceleration in the Z-axis direction (opposite to the Z-axis arrow direction) (acceleration of −α with the acceleration in the Z-axis arrow direction being positive) is applied, the resonance frequency F1 is f1 = 38 kHz, and F2 is f2 = Assume that the frequency has changed to 42 kHz. At this time, the absolute value | f2-f1 | of the difference frequency is 4 kHz. Conversely, when the same acceleration (+ α acceleration) is applied in the + Z-axis direction (Z-axis arrow direction), the resonance frequency F1 changes to f1 = 42 kHz, and F2 changes to f2 = 38 kHz. At this time, the absolute value | f2-f1 | of the difference frequency is 4 kHz. As described above, when the acceleration detection unit having the differential structure is configured by using the two stress sensitive elements 30 and 31, the difference frequency becomes twice as large as the change amount 2 kHz in the case of one stress sensitive element, and the acceleration detection is performed. Sensitivity is doubled.

However, acceleration is a vector and has a magnitude and direction. In order to detect the vector direction, a difference may be set in advance in the resonance frequency when the first and second stress sensitive elements 30 and 31 are not loaded. For example, the resonance frequencies F1 and F2 when the first and second stress sensitive elements 30 and 31 are unloaded are set to 40 kHz and 50 kHz, respectively. −Acceleration in the Z-axis direction (opposite to the Z-axis arrow direction) (acceleration of −α with the acceleration in the Z-axis arrow direction being positive) is applied, the resonance frequency F1 is f1 = 38 kHz, and F2 is f2 = Assume that the frequency has changed to 52 kHz. At this time, the difference frequency (f2-f1) is 14 kHz. Conversely, when the same acceleration (+ α acceleration) is applied in the + Z-axis direction (Z-axis arrow direction), the resonance frequency F1 changes to f1 = 42 kHz, and F2 changes to f2 = 48 kHz. In this case, the difference frequency (f2-f1) is 6 kHz. Thus, centering on the resonance frequency difference of 10 kHz when the first and second stress sensitive elements 30 and 31 are unloaded, when the acceleration of -α is applied, it changes to 14 kHz, and when the acceleration of + α is applied, the frequency changes to 6 kHz. Therefore, it is possible to detect the direction of acceleration.
In addition, since the acceleration detection unit 3 having a differential structure is configured by using two stress sensitive elements, if two elements having the same sensitivity are used for the two stress sensitive elements 30, 31, the other axis, for example, the Y-axis direction With respect to the acceleration, the frequency changes of the two stress sensitive elements are the same, and can be canceled by using the difference between the two frequencies. Further, the acceleration detection sensitivity of the acceleration detection unit 3 can be varied by changing the mass of the movable member.

  6 (a), 6 (b), and 6 (c) are perspective views illustrating a method for manufacturing an acceleration sensing unit according to an embodiment of the present invention. For example, as shown in FIG. 2, the acceleration sensing unit includes a fixed member 5 that is not displaced by application of acceleration, an element support member 7 that includes a movable member 20 supported by the beam 11 on the fixed member 5, and a stress-sensitive member. And a stress sensitive element 30 having fixed ends 32 and 33 integrated at both ends of the stress sensitive part 34. The beam 11 has a flexible structure that can be deformed to displace the movable member 20 in the acceleration detection axis direction (Z-axis direction) when acceleration is applied to the movable member 20. The stress sensitive element 30 is supported by the fixed member 5 and the movable member 20 at both fixed ends 32 and 33, respectively. The present embodiment is a method of manufacturing an acceleration sensing unit having such a configuration, and as shown in FIG. 6A, a plurality of stress sensitive elements 41 connected by element support pieces 43 and arranged in a planar shape. A step of preparing a stress-sensitive element substrate 40 having ', and an element support substrate 50 having a plurality of element support members 51 connected by a support piece 53 and arranged in a plane as shown in FIG. 6B. And preparing a process. Further, in order to connect the fixed end 44 of each stress sensitive element 41 ′ to the fixed member 5 and the movable member 20 constituting each element support member 51, an adhesive is applied to the surface of each fixed member 5 and the movable member 20. As shown in FIG. 6C, the element supporting substrate 50 and the stress sensitive element substrate 40 are overlapped with each other, and after the adhesive is cured, the element supporting piece 43 and the supporting piece 53 are cut. And a process.

  The manufacturing method of the stress sensitive element substrate 40 will be described. A crystal thin plate (Z plate) having a predetermined size is used, a metal thin film is formed on the crystal thin plate by means of vapor deposition or sputtering, and a known photolithography technique is used. When the crystal thin plate is etched by using an etching technique, a crystal double tuning fork plate 41 surrounded by a broken line in FIG. 6A (excitation electrode and electrode terminal not shown are formed on the crystal double tuning fork plate is a stress sensitive element 41. A stress-sensitive element substrate 40 in which ') is arranged in a matrix is obtained. The quartz twin tuning fork plate 41 has a structure in which a rectangular annular frame 42 is held by a plurality of element support pieces 43. A metal mask (not shown) is set on the stress sensitive element substrate 40 and placed in a vapor deposition apparatus or the like, and excitation electrodes, electrode terminals, and the like are formed on each crystal twin tuning fork plate 41 in a vacuum to manufacture the stress sensitive element substrate 40. .

Next, using a quartz plate (Z plate) with a predetermined thickness, the quartz plate is processed using a photolithography technique and an etching technique, and the element support members 51 surrounded by broken lines in FIG. The element support substrate 50 arranged in the above is formed. The element support member 51 including the fixed member 5, the beam 11, and the movable member 20 has a structure in which a rectangular annular frame body 52 is held by a plurality of support pieces 53. Then, as shown in FIG. 6C, the stress-sensitive element substrate 40 having electrodes and the like is aligned with the element support substrate 50 in which the adhesive is applied to the fixed member 5 and the movable member 20 of the plurality of element support members 51. After the elements are superposed and heated and dried, the element support piece 43 and the support piece 53 are cut using a dicing saw or the like to obtain the acceleration sensing unit shown in FIG. As a method for bonding the stress sensitive element substrate 40 and the element support substrate 50, various methods such as a method of melting and bonding glass at a high temperature, a method of bonding using gold tin, and an anodic bonding method can be used. It is.
In addition, when the mass of the movable member 20 is insufficient and the acceleration detection sensitivity is low, the acceleration detection sensitivity can be improved by adding masses having substantially the same weight to the upper and lower surfaces of the movable member 20.
If a large number of acceleration detection units are manufactured collectively by such a method, acceleration detection units with small variations in the quality of acceleration detection performance can be efficiently obtained in large quantities.

Note that the method of manufacturing the acceleration detection unit shown in FIG. 6 may be applied as a method for configuring the acceleration detection unit 3 as shown in FIG. That is, the element support substrate 50 in which an adhesive is applied to the upper and lower surfaces of the fixed member 5 and the movable member 20 of the plurality of element support members 51 so that the element support substrate 50 is sandwiched between the two stress sensitive element substrates 40. In addition, the stress-sensitive element substrate 40 on which the electrodes and the like are formed are stacked so as to be aligned and heated and dried, and then the element support piece 43 and the support piece 53 are cut using a dicing saw or the like, and the acceleration detection unit 3 is You can make it.
Further, as in the case of the acceleration detection unit shown in FIG. 3, an element support substrate 50 in which the protrusion 9 is formed on the element support member 51 and a stress sensitive element substrate 40 in which the hole 38 is formed in the crystal twin tuning fork plate 41 are prepared. However, a method of manufacturing an acceleration detection unit based on the manufacturing method shown in FIG.

Further, as shown in FIG. 6, the element support piece 43 is much thinner than the width of the fixed end of the stress sensitive element 41 ′, and the support piece 53 is extremely narrow compared to the fixed member and the movable member. If the element support piece 43 and the support piece 53 are to be cut without damaging the fixed end of the stress sensitive element 41 ′ and the fixed member and the movable member, the element support piece 43 and the support piece 53 are generally fixed to the fixed end. Then, it is impossible to cut without leaving the movable member and the fixed member completely.
However, if the element support piece 43 and the support piece 53 are thin as described above, the amount of each support piece that cannot be cut and remains in the acceleration detection unit can be made small. Therefore, in particular, the mass setting condition of the movable member 20 is not greatly deviated by the remaining amount of the support piece, so that it is possible to efficiently obtain a large number of acceleration detection units with small variations in the quality of acceleration detection performance among individuals. .

  In the manufacturing method of the acceleration detection unit, the manufacturing method of cutting the element supporting piece 43 of the stress sensitive element substrate 40 and the supporting piece 53 of the element supporting substrate 50 using a dicing saw or the like has been described. There is a point that the cutting pieces of the element support piece 43 and the support piece 53 remain slightly on the fixed portion of the element 41 ′ and the movable member 20 of the element support member 51, respectively. Therefore, the second manufacturing of the acceleration detection unit in which the element support piece 43 and the cutting residue of the support piece 53 do not remain in the fixed portion of the stress sensitive element 41 ′ and the fixed member 5 and the movable member 20 of the element support member 51, respectively. A method will be described.

8 to 11 are views for explaining a second manufacturing method of the acceleration sensing unit according to the embodiment of the present invention. The configuration of the acceleration sensing unit is the same as that in the first manufacturing method, and a description thereof will be omitted.
As shown in FIG. 8A, the second manufacturing method of the acceleration detection unit of the present embodiment is individually made up of a frame body 52, a plurality of support pieces 53 provided on the frame body 52, and each support piece 53. A step of preparing an element support substrate 55 having an element support member 51 supported on the frame, and a support that constitutes the element support substrate 55 with respect to the frame 62 and the frame 62 as shown in FIG. Preparing at least one weight member support substrate 60 having a plurality of weight member support pieces 63 provided at the same position as the piece 53 and weight members 61 individually supported by each weight member support piece 63; Have. Further, as shown in FIG. 9A, the second manufacturing method includes a frame body 42, and a plurality of support pieces 53 provided at the same position as the support piece 53 constituting the element support substrate 55 with respect to the frame body 42. Preparing a stress sensitive element substrate 40 having an element supporting piece 43 and a stress sensitive element 41 ′ individually supported by each element supporting piece 43.

  The element supporting substrate 55, the weight member supporting substrate 60, and the stress sensitive element substrate 40 are manufactured by using a quartz plate (Z plate) having a predetermined thickness, and using the photolithography technique and the etching method described above, the quartz plate. Are each processed into a desired shape. Further, each support piece 53 of the element support substrate 55 is shown in an enlarged plan view of a main part (a view seen from the Z-axis direction) of FIG. 8B at a portion where the support piece 53 is joined to each fixing member 5. Such an easy-to-break part, that is, a groove (recess) 54 is formed along the Z-axis direction, which is strong against a force in the Z-axis direction, but can be easily broken and cut by applying a force in the Y-axis direction. Is formed. Further, each weight member support piece 63 of the weight member support substrate 60 has a main part enlarged side view (from the Y-axis direction) of FIG. 8D at a portion where the weight member support piece 63 is joined to each weight member 61. As shown in the drawing, an easy-to-break portion, that is, a groove (recess) 64 is formed along the Y-axis direction (toward the depth direction of the recess 54), and a force is applied in the Z-axis direction. It is formed so that it can be easily broken and cut. Similarly, each element support piece 43 of the stress sensitive element substrate 40 has a main part enlarged side view of FIG. 9B at a portion where the element support piece 43 joins the fixing portion 44 of each stress sensitive element 41 ′. As shown in the drawing (viewed from the Y-axis direction), an easily breakable portion, that is, a groove (recess) 45 is formed along the Y-axis direction (toward the depth direction of the recess 54), and in the Z-axis direction. It is formed so that it can be easily broken and cut by applying force. The stress sensitive element substrate 40 shown in FIG. 9A shows an example in which electrodes (not shown), electrode terminals 46, and the like are formed through a mask (not shown) in a vacuum apparatus.

  Then, as shown in FIGS. 10 and 11, in order to connect each weight member 61 to at least one surface of the fixed member 5 and the movable member 20 constituting each element support member 51, each fixed member 5 and each movable member 20 are connected. In the state where the weight member support pieces 63 are overlapped with the support pieces 53, the element support substrate 55 and the weight member support substrate 60 are overlapped to form the substrate laminate A. . After the adhesive is cured, each weight member support piece 63 is cut off from the substrate laminate A by folding. The perspective view shown in FIG. 11A is a diagram showing an example in which the weight members 61 are bonded to the upper and lower surfaces of the fixed member 5 and the movable member 20. And as shown in FIG.11 (b), in order to connect the fixed end 44 of each stress sensitive element 41 'with respect to one surface of each weight member 61 which comprises the board | substrate laminated body A, each weight member An adhesive is applied to one surface of 61, and a substrate laminate B is formed by superimposing the substrate laminate A and the stress sensitive element substrate 40 in a state where the element support pieces 43 are superimposed on the support pieces 53. To do. After the adhesive is cured, as shown in FIG. 11C, a step of cutting off the element supporting piece 43 of the stress sensitive element substrate 40 from the substrate laminate B and a supporting piece 53 of the element supporting substrate 55. The second manufacturing method of the acceleration detection unit is constituted by the step of cutting by cutting. The weight member 61 may be connected to at least the movable member 20.

  11 (a) to 11 (c) show process diagrams in which the weight members 61 are superposed and bonded to the upper and lower surfaces of each fixed member 5 and movable member 20, but the fixed member 5 and movable member are shown. The acceleration detection unit may be configured in a process in which the weight members 61 are superposed and bonded to any one of the surfaces. In this case, the stress sensitive element substrate 40 may be superimposed on the surfaces of the fixed members 5 and the movable members 20 or the surfaces of the weight members 61 superimposed on the surfaces of the fixed members 5 and the movable members 20. .

  A feature of the second manufacturing method of the acceleration detection unit is that the element support substrate 55, the weight member support substrate 60, and the support piece 53 formed on the stress sensitive element substrate 40, the weight member support piece 63, and the element support piece 43 include an element The support member 51, the weight member 61, and the stress sensitive element 41 ′ are formed to be sufficiently narrower than the fixing portion 44, and the support piece 53, the weight member support piece 63, and the element support piece 43 have grooves (recesses), respectively. 5) Since 54, 64, 45 are formed, it can be easily cut off by folding. In addition, since the grooves (recesses) 54, 64, 45 are provided, the support piece 53, the weight member support piece 63, and the remaining pieces of the element support piece 43 can be made extremely small, and a highly accurate acceleration sensing unit. Can be produced in large quantities.

Next, the 3rd manufacturing method of the acceleration detection unit which concerns on embodiment of this invention is demonstrated. Since the configuration of the acceleration sensing unit has been described above, a description thereof will be omitted. Also, the step of preparing the element support substrate 55, the step of preparing at least one weight member support substrate 60, the step of preparing the stress sensitive element substrate 40, and the element support substrate 55 and the weight member support substrate 60 are overlapped. Since the step of forming the substrate laminate by combining them and the step of superimposing the substrate laminate and the stress sensitive element substrate 40 have been described in the second manufacturing method, they are omitted. The third manufacturing method is different from the second manufacturing method in that the element support substrate 55 and the weight member support substrate 60 are overlapped to form a substrate laminate A, and the stress sensitive element substrate 40 is formed on the substrate laminate A. Are stacked to form the substrate laminate B, and after the adhesive is cured, the element support piece 43, the weight member support piece 63, and the support piece 53 are collectively cut and cut.
The feature of the third manufacturing method of the acceleration detection unit is that the element support piece 43, the weight member support piece 63, and the support piece 53 can be cut at a time, so that the efficiency is improved.

  Next, the 4th manufacturing method of the acceleration detection unit which concerns on embodiment of this invention is demonstrated. As shown in FIG. 12, the fourth method of manufacturing the acceleration sensing unit includes a frame body 52, a plurality of support pieces 53 provided on the frame body 52, and element support members individually supported by the support pieces 53. A step of preparing an element support substrate 55 having 51, a frame body 42, a plurality of element support pieces 43 provided at the same position as the support pieces 53 constituting the element support substrate 55 with respect to the frame body 42, and Preparing a stress sensitive element substrate 40 having stress sensitive elements 41 ′ individually supported by the element support pieces 43. Further, an adhesive is applied to each fixed member 5 and movable member 20 in order to connect the fixed end 44 of each stress sensitive element 41 ′ to the fixed member 5 and movable member 20 constituting each element support member 51. And a step of superposing the element support substrate 55 and the stress sensitive element substrate 40 in a state where the element support pieces 43 are overlapped on the support pieces 53 to form a substrate laminate. . And after passing through the process of hardening the adhesive agent of a board | substrate laminated body, from the board | substrate laminated body of the element support substrate 55 and the stress sensitive element board | substrate 40, the process of cutting off the support piece 53 and the element support 43 by cutting off. Become.

In the fourth method of manufacturing the acceleration detection unit, the element support substrate 55 and the stress sensitive element substrate 40 may be provided with grooves 54 and 45 as shown in FIGS. 8B and 9B. However, it may not be provided.
According to the fourth manufacturing method of the acceleration detection unit, since the weight member support substrate 60 is not required, there is an advantage that the manufacturing process is simplified and the cost is reduced.

  FIG. 13A is a side view showing the configuration of the acceleration sensor 70, and FIG. 13B is a plan view. The acceleration sensor 70 is electrically connected to, for example, the acceleration detection unit 3, a housing (fixed portion) 75 that hermetically seals the acceleration detection unit 3, and excitation electrodes that constitute the stress sensitive elements 30 and 31. The oscillation circuit 80 is provided. The acceleration detection unit 3 shown in FIG. 13 is the one in which the acceleration detection unit 3 shown in FIG. 4 is tilted sideways. The acceleration detection unit 3 is bonded and fixed to the mounting table 78 and the electrode terminals 39 of the stress sensitive elements 30 and 31 and the oscillation circuit 80. Are connected by a bonding wire 85. The electrode terminal of the oscillation circuit 80 is electrically connected to the external terminal 77 of the housing 75 through the mounting table 78. The housing 75 is covered with a lid 76 and the inside is sealed to form an airtight structure.

  According to the method of manufacturing the acceleration detection unit according to the embodiment of the present invention, the quartz material is used for the stress sensitive element, the element supporting member for supporting the stress sensitive element, and the weight member, both of which are photolithography technique and etching. Since it manufactures by a batch process using a method, it has the advantage that it is excellent in mass productivity compared with the case where the element supporting member which consists of metal materials is used, and manufacturing cost can be reduced. In addition, since quartz is used for the element support member, stress sensitive element and weight member, and a substrate cut at the same cut angle is used, the linear expansion coefficients of the three parties are the same, and the three parties are affected by the surrounding thermal fluctuations. The thermal distortion of can be suppressed to a small level. The conventional acceleration sensor made of silicon has the ability to detect stress after being bent several microns, whereas this acceleration sensor is capable of detecting a very small deflection of the beam (fixed end) due to a small acceleration. There is an advantage that the response speed is high, and the accuracy and reproducibility are good.

  The manufacturing process described in this embodiment is merely an example, and the method for manufacturing the acceleration detection unit of the present invention is not limited to the manufacturing method described in this embodiment, and the process procedure and the like can be changed as appropriate. Needless to say.

The schematic perspective view which showed the structure of the acceleration detection unit which concerns on this invention. The schematic perspective view which showed the structure of the acceleration detection unit of the 2nd Example. The schematic perspective view which showed the structure of the acceleration detection unit of the 3rd Example. The schematic perspective view which showed the structure of the acceleration detection unit of the 4th Example. The figure which shows the acceleration measuring circuit which consists of an oscillation circuit, a mixer, a low-pass filter, and a frequency-voltage converter. (A) is a figure which shows a stress sensitive element board | substrate, (b) is a figure which shows an element support substrate, (c) is a figure which shows the board | substrate laminated body which piled up the element support board | substrate and the stress sensitive element board | substrate. The schematic perspective view which showed the structure of the acceleration detection unit. (A) is a figure which shows an element support substrate, (b) The principal part enlarged view of a support piece, (c) is a figure which shows a weight member support board, (d) is a principal part enlarged view of a weight member support piece. (A) is a figure which shows a stress sensitive element board | substrate, (b) is a principal part enlarged view of an element support piece. The figure which shows the board | substrate laminated body of an element support substrate and a weight member support substrate. (A) The figure which shows the board | substrate laminated body of an element support substrate and a weight member support board, (b) is a figure which shows a mode that a stress sensitive element board | substrate is piled up on a board | substrate laminated body, (c) is the process cut | disconnected by folding FIG. The figure which shows the laminated substrate of an element support substrate, a weight member support substrate, and a stress sensitive element substrate. It is a figure which shows the structure of an acceleration sensor, (a) is a side view, (b) is a top view. The figure which shows the conventional acceleration sensor.

Explanation of symbols

  1, 2, 3 Acceleration detection unit, 5 fixed member, 5a (fixed member) upper surface, 6, 7, 51 element support member, 10, 11 beam, 20 movable member, 20a (movable member) upper surface, 30, 31 , 41 'Stress sensitive element, 32, 33, 44 Fixed end, 34 Stress sensitive part, 38 holes, 39 Electrode terminal, 40 Stress sensitive element substrate (crystal double tuning fork substrate), 41 Crystal double tuning fork plate, 42, 52 Frame , 43 Element support piece, 45 groove, 46 Electrode terminal, 50, 55 Element support substrate, 53 Support piece, 54, 64 groove, 60 Weight member support substrate, 61 Weight member, 62 Frame body, 63 Weight member support piece, A , B substrate laminate, 70 acceleration sensor, 75 housing, 76 lid, 77 external terminal, 78 mounting table, 80 oscillation circuit, 85 bonding wire

Claims (6)

An element support member comprising a fixed member, and a movable member supported by a beam on the fixed member; a stress sensitive element having a stress sensitive part and fixed ends integrated at both ends of the stress sensitive part; The beam is configured to have a flexibility that can be deformed so as to displace the movable member along an acceleration detection axis direction when acceleration is applied to the movable member, and the stress sensitive element includes A method of manufacturing an acceleration detection unit having a configuration in which both fixed ends are respectively supported by a fixed member and the movable member,
Preparing an element support substrate having a plurality of the element support members connected by a support piece and arranged in a plane;
Preparing a stress sensitive element substrate having a plurality of stress sensitive elements connected by an element support piece and arranged in a plane;
Superposing the element support substrate and the stress sensitive element substrate on the fixed member and the movable member so as to overlap the fixed ends of the stress sensitive elements; and
Fixing the fixed end on the fixed member and the movable member;
And a step of cutting the element support piece and the support piece.   The method for manufacturing an acceleration detection unit according to claim 1, wherein the support piece, the element, and the support piece overlap each other during the superimposing step. An element support member comprising a fixed member, and a movable member supported by a beam on the fixed member; a stress sensitive element having a stress sensitive part and fixed ends integrated at both ends of the stress sensitive part; The beam is configured to have a flexibility that can be deformed so as to displace the movable member along an acceleration detection axis direction when acceleration is applied to the movable member, and the stress sensitive element includes A method of manufacturing an acceleration detection unit having a configuration in which both fixed ends are respectively supported by a fixed member and the movable member,
A step of preparing an element support substrate having a plurality of element support members connected by a support piece and arranged in a plane;
Preparing at least one weight member support substrate having a plurality of weight members connected in a weight member support piece and arranged in a planar shape;
Preparing a stress sensitive element substrate having a plurality of stress sensitive elements connected by an element support piece and arranged in a plane;
Forming a substrate laminate by superimposing the element support substrate and the weight member support substrate in order to connect the weight member to at least the movable member;
Cutting the weight member support piece;
Superimposing the substrate laminate and the stress sensitive element substrate to connect the substrate laminate and the fixed end of each stress sensitive element, cutting the element support piece and the support piece,
A method of manufacturing an acceleration detection unit comprising: An element support member comprising a fixed member, and a movable member supported by a beam on the fixed member; a stress sensitive element having a stress sensitive part and fixed ends integrated at both ends of the stress sensitive part; The beam is configured to have a flexibility that can be deformed so as to displace the movable member along an acceleration detection axis direction when acceleration is applied to the movable member, and the stress sensitive element includes A method of manufacturing an acceleration detection unit having a configuration in which both fixed ends are respectively supported by a fixed member and the movable member,
A step of preparing an element support substrate having a plurality of element support members connected by a support piece and arranged in a plane;
Preparing a stress sensitive element substrate having a plurality of stress sensitive elements connected by an element support piece and arranged in a plane;
Preparing at least one weight member support substrate having a plurality of weight members connected in a weight member support piece and arranged in a planar shape;
Forming a substrate laminate by superimposing the element support substrate and the weight member support substrate to connect the weight member to at least the movable member;
Superimposing the substrate laminate and the stress sensitive element substrate to connect the substrate laminate and the fixed end of each stress sensitive element;
Cutting the support piece, the weight member support piece, and the element support piece;
A method of manufacturing an acceleration detection unit comprising:   The method for manufacturing an acceleration detection unit according to claim 3, wherein the support piece, the element support piece, and the weight support piece are provided with a recess.   The recess provided in the support piece is a groove formed along the thickness direction of the stress sensitive element substrate, and the recess provided in the element support piece and the weight support piece is provided in the support piece. The method for manufacturing an acceleration detection unit according to claim 5, wherein the groove extends in the depth direction of the recess.

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