Inertial force sensor and method for manufacturing the same

Abstract

To provide an inertial force sensor including a glass vibrator that is hermetically sealed in a highly evacuated package.SOLUTION: An inertial force sensor includes a package and a lower substrate whose back surface is adhesively fixed to a mounting surface in the package. The inertial force sensor includes a glass substrate disposed on the front surface of the lower substrate, and an electrode portion disposed on the front surface of the glass substrate. The inertial force sensor includes a glass vibrator whose column portion is fixed to the electrode portion. A groove is formed on either the front surface of the lower substrate or the back surface of the glass substrate. When viewed from a direction perpendicular to the lower substrate, the groove intersects with at least one of the periphery of the lower substrate and the periphery of the glass substrate. An opening portion is formed on the back surface of the lower substrate. When viewed from a direction perpendicular to the lower substrate, the opening portion and the groove communicate with each other at an overlapping portion between the opening portion and the groove. A die bond material is disposed between the back surface of the lower substrate and the mounting surface.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This specification relates to an inertial force sensor and a method for manufacturing the inertial force sensor.

Background Art

[0002] Patent Document 1 discloses a Bird-bath Resonator Gyroscope (BRG) using a glass vibrator made of fused silica as a gyro sensor capable of achieving high precision. The glass vibrator is hermetically sealed in a package. As the degree of vacuum increases, the inhibitory factors that attenuate the vibration energy of the glass vibrator can be reduced, so that a gyro sensor with higher precision can be realized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to store the glass vibrator in a package, an electrode substrate laminated with a glass substrate and a semiconductor substrate is used. The glass vibrator is fixed to the electrode substrate. The back surface of the glass substrate is adhesively fixed to the mounting surface in the package by a die bonding material. Gas is discharged from this die bonding material. However, if the gas cannot be sufficiently discharged from the die bonding material, outgassing may occur from the die bonding material after hermetic sealing. It becomes difficult to achieve a high vacuum inside the package or to maintain a high vacuum state.

Means for Solving the Problems

[0005] The inertial force sensor disclosed in this specification includes a package that can be hermetically sealed by a lid. The inertial force sensor includes a lower substrate stored in the package. The back surface of the lower substrate is adhesively fixed to the mounting surface in the package. The inertial force sensor includes a glass substrate disposed on the surface of the lower substrate. The inertial force sensor includes an electrode portion disposed on the surface of the glass substrate. The inertial force sensor includes a glass vibrator including a tubular column portion having a central axis and a hollow substantially hemispherical peripheral portion centered on the central axis. In the glass vibrator, the column portion is fixed to the electrode portion. A groove is formed on either the surface of the lower substrate or the back surface of the glass substrate. When viewed from a direction perpendicular to the lower substrate, the groove intersects at least one of the outer periphery of the lower substrate and the outer periphery of the glass substrate. An opening is formed on the back surface of the lower substrate. When viewed from a direction perpendicular to the lower substrate, the opening and the groove communicate with each other at the overlapping portion of the opening and the groove. A die bond material is disposed between the back surface of the lower substrate and the mounting surface.

[0006] Gas is released from inside the die bond material disposed between the back surface of the lower substrate and the mounting surface. According to the above structure, this released gas can be efficiently discharged to the outside through the groove from the opening formed on the back surface of the lower substrate. Since the gas can be sufficiently discharged from the die bond material, it is possible to suppress outgassing generated from the die bond material after vacuum hermetic sealing. It becomes possible to achieve a high vacuum inside the package and maintain a high vacuum state.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Mode for Carrying Out the Invention

Examples

[0008] FIG. 1 shows a top view of the gyro sensor 1 according to the present embodiment. In FIG. 1, for clarity, the state where the lid 130 is removed is shown. Further, FIG. 2 shows a cross-sectional view taken along line II-II. FIG. 2 is a cross-sectional view passing through the central axis CA. The gyro sensor 1 includes a sensor element 10 and a package 100. The sensor element 10 is hermetically sealed in the package 100.

[0009] (Configuration of the sensor element 10) Fig. 3 shows an enlarged cross-sectional view of the sensor element 10. Fig. 3 is a view obtained by enlarging the vicinity of the sensor element 10 in the cross-sectional view of Fig. 2. The sensor element 10 mainly includes a pedestal electrode 20, a glass resonator 30, and a paste 40. The pedestal electrode 20 has a structure in which a glass substrate 21 and a silicon substrate 22 are laminated on a lower substrate 26.

[0010] The lower substrate 26 will be described. Fig. 4(A) shows a top view of the upper surface of the lower substrate 26. Also, Figs. 4(B) - 4(D) show cross-sectional views. Fig. 4(B) is a cross-sectional view taken along line B - B (a line parallel to the x-axis and passing through the groove 26t). Fig. 4(C) is a cross-sectional view taken along line C - C (a line parallel to the x-axis and not passing through the groove 26t). Fig. 4(D) is a cross-sectional view taken along line D - D (a line parallel to the y-axis). Fig. 5 shows a bottom view of the lower substrate 26.

[0011] The lower substrate 26 has a rectangular shape when viewed from a direction (z-direction) perpendicular to the lower substrate 26. The lower substrate 26 includes a side 26y parallel to the y-axis and a side 26x parallel to the x-axis. The material of the lower substrate 26 may be various. In this embodiment, the material of the lower substrate 26 is silicon. Thereby, anodic bonding between the lower substrate 26 and the glass substrate 21 is possible. Also, the thickness of the lower substrate 26 is not particularly limited as long as it has the strength as a self-supporting substrate.

[0012] A plurality of grooves 26t are formed on the surface 26f of the lower substrate 26. Since the shapes and functions of each of the plurality of grooves 26t are common, hereinafter, there may be a case where a representative one of the grooves 26t is described. The plurality of grooves 26t extend in the x-direction. The groove 26t intersects the side 26y located on the outer periphery of the lower substrate 26. In other words, the groove 26t reaches the ends of the lower substrate 26 in the ±x direction.

[0013] The cross-sectional shape of the groove 26t may be various. In this embodiment, as shown in FIG. 4(C), the cross-section of the groove 26t has a rectangular shape. This is because, as will be described later, the groove 26t is formed by anisotropic dry etching. Also, the depth of the groove 26t may be 10 μm or less, for example, about 1-2 μm.

[0014] As shown in FIG. 3, the surface 26f of the lower substrate 26 is joined to the back surface 21b of the glass substrate 21. The back surface 21b can block the upper surface of the groove 26t. Thereby, as will be described later, the groove 26t can function as a discharge path for outgas discharged from the die bonding material 50.

[0015] Also, a plurality of openings 26a are formed in the lower substrate 26. The plurality of openings 26a penetrate the lower substrate 26 in the thickness direction (z direction). Since the shapes and functions of each of the plurality of openings 26a are common, hereinafter, there may be a case where a representative one of the openings 26a is described. The plurality of openings 26a have a groove shape extending in the y direction. That is, when viewed from the direction (z direction) perpendicular to the lower substrate 26, the plurality of grooves 26t and the plurality of openings 26a are in an orthogonal relationship. Also, the plurality of openings 26a do not reach the ends of the lower substrate 26 in the ±y direction.

[0016] As shown in FIG. 4(C), the plurality of openings 26a penetrate the lower substrate 26 in the thickness direction. Also, as shown in FIG. 4(A), when viewed from the direction perpendicular to the lower substrate 26, an overlapping portion OL is formed at the intersection of the plurality of openings 26a and the plurality of grooves 26t. In this overlapping portion OL, the opening 26a and the groove 26t communicate with each other (see FIG. 4(B)). Thereby, as will be described later, the opening 26a can function as a communication path for allowing the outgas discharged from the die bonding material 50 to escape to the groove 26t. Note that in FIGS. 4(A) and 4(B), for convenience, a representative one of the overlapping portions OL is described. However, actually, the overlapping portion OL is formed at all intersections of the plurality of openings 26a and the plurality of grooves 26t.

[0017] The opening 26a has a depth D1 and a width W1. The depth D1 is equal to or greater than the width W1. The cross-sectional shape of the opening 26a may be various. In this embodiment, as shown in FIG. 4(B), it has a cross-sectional shape with a taper angle of the side wall being substantially perpendicular. This is because, as will be described later, the opening 26a is formed by an anisotropic deep etching technique.

[0018] Here, as shown in FIG. 5, focus on the central region R1 of the lower substrate 26. The central region R1 is a region located near the center of the lower substrate 26. The method for determining the central region R1 in this embodiment will be described. The rectangular shape of the lower substrate 26 is divided into nine rectangular shapes having the same shape as each other. Then, the region occupied by one rectangular shape located at the center thereof is defined as the central region R1. Also, the region occupied by the eight rectangular shapes surrounding the central region is defined as the outer peripheral region R2. In the central region R1, the density of the formation of a plurality of openings 26a is made higher than that in the outer peripheral region R2.

[0019] The glass substrate 21 is a glass material that can be anodically bonded to the silicon substrate 22. Since anodic bonding can be carried out by a general technique in the art, the description thereof is omitted here. In this embodiment, the material of the glass substrate 21 is borosilicate glass containing Na (also called borosilicate glass). An annular ring groove 21r is formed on the surface 21f of the glass substrate 21. The rim portion 30r of the glass oscillator 30 is inserted into the ring groove 21r.

[0020] The silicon substrate 22 includes an annular electrode 22c, a plurality of divided electrodes 22d, and an outer peripheral electrode 22o, and constitutes an electrode portion. The annular electrode 22c is disposed on the surface 21f of the glass substrate 21. The annular electrode 22c has a cylindrical shape around the central axis CA and has a through hole 22h. The central axis CA passes through the center of the glass substrate 21 and is an axis perpendicular to the surface 21f. The plurality of divided electrodes 22d are rotationally symmetrically arranged on a circumference centered on the central axis CA. The plurality of divided electrodes 22d surround the annular electrode 22c. An electrode pad 23 is formed on each of the plurality of divided electrodes 22d. An annular ring through portion 22r is formed between the outer periphery of the annular electrode 22c and the inner periphery of the plurality of divided electrodes 22d. The rim portion 30r of the glass oscillator 30 is inserted into the ring through portion 22r. The outer peripheral electrode 22o surrounds the divided electrodes 22d. The outer peripheral electrode 22o is connected to the annular electrode 22c by four wirings 25. In this embodiment, the wiring 25 is formed of an Al film. BR pads 24 are disposed at the four corners of the outer peripheral electrode 22o.

[0021] The glass oscillator 30 includes a column portion 30p and a peripheral portion 30c. The column portion 30p is a tubular portion having the central axis CA. The peripheral portion 30c is a hollow substantially hemispherical portion centered on the central axis CA. As shown in FIG. 3, the cross-sectional shape of the glass oscillator 30 in a plane passing through the central axis CA is substantially M-shaped. The material of the glass oscillator 30 is fused silica (quartz).

[0022] A conductive film (not shown) is formed on the surface of the glass oscillator 30. Various materials can be used for the conductive film. In this embodiment, the conductive film is a TiN film. The conductive film can be formed to have a nano-level thickness by film formation by ALD (Atomic Layer Deposition). The thickness of the conductive film can be, for example, in the range of 5 - 30 nm. In this embodiment, the thickness is 10 nm.

[0023] The quartz resonator 30 is fixed to the annular electrode 22c such that the central axis CA of the column portion 30p coincides with the central axis CA of the annular electrode 22c. Specifically, the bottom of the column portion 30p is adhered to the annular electrode 22c by a paste 40. The paste 40 is a so-called conductive paste. The material form of the paste 40 is the same as that of the die bond material 50 described later. The paste 40 electrically connects the conductive film on the surface of the quartz resonator 30 and the annular electrode 22c. The annular electrode 22c is connected to the BR pad 24 via the wiring 25 and the outer peripheral electrode 22o. Therefore, the conductive film on the surface of the quartz resonator 30 and the BR pad 24 are electrically connected.

[0024] (Arrangement mode of the die bond material 50) As shown in FIG. 3, a die bond material 50 is disposed between the back surface 26b of the lower substrate 26 and the mounting surface 101 of the package 100. The die bond material 50 is a conductive material used to adhesively fix the lower substrate 26 to the mounting surface 101. The die bond material 50 is a material that hardens by applying heat and exhibits conductivity. Various materials can be used for the die bond material 50. For example, it may be a paste material (Ag paste) in which Ag particles are mixed with an organic material of a binder. When heat is applied to the Ag paste, the binder sublimes and the Ag hardens, exhibiting an adhesive function and conductivity.

[0025] The die bond material 50 has entered from the back surface 26b side of the opening 26a into the inner side of the opening 26a. A space SP is formed by the void remaining between the entering die bond material 50 and the back surface 21b of the glass substrate 21.

[0026] FIG. 6 illustrates the arrangement pattern of the die bond region DR when viewed from a direction (z direction) perpendicular to the lower substrate 26. In FIG. 6, for clarity, only the lower substrate 26, the die bond region DR, and the package 100 are shown. The die bond region DR is a region where the die bond material 50 exists and is a region formed within the lower substrate 26. FIG. 6 shows an example in which the die bond region DR is arranged over the entire area where the lower substrate 26 is located. Also in FIG. 6, the outer peripheral contour of the die bond region DR is indicated by a dotted line. The outer periphery of the lower substrate 26 and the outer peripheral contour of the die bond region DR are substantially coincident.

[0027] (Configuration of Package 100) The configuration of the package 100 will be described with reference to FIGS. 1 and 2. The package 100 is configured to be hermetically sealable by a lid 130. A metal mounting surface 101 is disposed on the bottom surface inside the package 100. The mounting surface 101 is the surface on which the sensor element 10 is fixed by the die bond material 50.

[0028] A plurality of electrodes 102 are arranged so as to surround the mounting surface 101. A plurality of electrode pads 23 provided on the sensor element 10 are connected to the corresponding electrodes 102 by wire bonds 110. In this embodiment, the wire bonds 110 are made of Au wires. Also, as shown in FIG. 2, a plurality of pads 102p are disposed outside the package 100. The plurality of pads 102p correspond to each of the plurality of electrodes 102 and are connected to each of the plurality of electrodes 102. The gyro sensor 1 can be connected to an external control circuit (not shown) via the plurality of pads 102p.

[0029] A rectangular frame 103 is arranged on the outer periphery of a plurality of electrodes 102. The frame 103 only needs to be an insulator, and various materials (e.g., ceramics) can be used. A seal portion 120 is arranged on the upper surface of the frame 103. The seal portion 120 includes a lower electrode frame 121, a seal ring 122, and an upper electrode frame 123. The lower electrode frame 121 is arranged on the upper surface of the frame 103. The upper electrode frame 123 is arranged on the lower surface of the lid 130. The lower electrode frame 121, the seal ring 122, and the upper electrode frame 123 are all in a rectangular frame shape, and their formation positions correspond to each other. The materials and thicknesses of the lower electrode frame 121, the seal ring 122, and the upper electrode frame 123 may vary. In this embodiment, the lower electrode frame 121 is an Au / Ni film, and the upper electrode frame 123 is an Au / Cr film. The seal ring 122 is made of AuSn with a thickness of about 100 μm.

[0030] The lid 130 is joined to the frame 103 by the seal portion 120. Thereby, the inside of the package 100 can be hermetically sealed. The material of the lid 130 is glass (e.g., borosilicate glass).

[0031] (Operation of the gyro sensor 1) A capacitor is formed between each of the plurality of divided electrodes 22d and the glass vibrator 30. An electrical signal is applied to the plurality of divided electrodes 22d from an external control circuit (not shown) via the plurality of pads 102p. By generating an electrostatic attraction force between the glass vibrator 30 and the plurality of divided electrodes 22d, the glass vibrator 30 is excited in a wine glass mode at the resonance frequency. When an angular velocity ωz is applied around the z-axis in this state, a Coriolis force is generated. Then, an amplitude corresponding to the generated Coriolis force is generated in the detection direction. The generated amplitude can be detected by a change in the capacitance of the capacitor formed between the divided electrode 22d and the glass vibrator 30. From the above, the gyro sensor 1, which is an inertial force sensor, functions.

[0032] (Manufacturing method of the gyro sensor 1) FIG. 7 shows a flowchart outlining the manufacturing process of the gyro sensor 1. In the glass molding step of step S1, the glass resonator 30 is molded from a molten silica (quartz) plate using a flame and a mold. In the step of forming the discharge path of step S2, a groove 26t is formed on the surface 26f of the lower substrate 26, and an opening 26a is formed on the back surface 26b. In the step of fabricating the pedestal electrode of step S3, the lower substrate 26, the glass substrate 21, and the silicon substrate 22 are anodically bonded to fabricate the pedestal electrode 20.

[0033] In the step of mounting the pedestal electrode of step S4, the pedestal electrode 20 is adhered to the mounting surface 101 of the package 100 with the die bonding material 50. In the step of mounting the glass resonator of step S5, the glass resonator 30 is fixed to the pedestal electrode 20 with the paste 40. In the step of vacuum hermetic sealing of step S6, the package 100 on which the glass resonator 30 and the pedestal electrode 20 are mounted is hermetically sealed in a vacuum. Through the above six steps, a glass resonator gyro sensor is manufactured. Each step will be described in detail below.

[0034] The glass molding step of step S1 will be described. First, the quartz plate is melt-molded using a glass molding apparatus. The specific details of the melt molding are omitted. The quartz plate with the glass resonator portion formed is removed from the mold. The glass resonator 30 is taken out from the quartz plate using CMP (Chemical Mechanical Polishing) or the like. Finally, a thin conductive film is formed on the surface of the glass resonator 30 by ALD. A film is uniformly formed on the inner and outer surfaces of the glass, and conductivity is imparted to the glass resonator 30.

[0035] Describe the step of forming the discharge path in step S2. First, a plurality of grooves 26t are formed on the surface 26f of the lower substrate 26. This will be specifically described with reference to FIG. 8. FIG. 8 is a cross-sectional view taken along the line D-D of FIG. 4. A resist layer 55 is applied to the surface 26f. Then, using well-known photolithography technology, a plurality of opening patterns 55p corresponding to the plurality of grooves 26t are formed in the resist layer 55. Through the plurality of opening patterns 55p, the surface 26f is anisotropically etched. In this embodiment, DRIE (Deep Reactive Ion Etching) is used. Thereby, a plurality of grooves 26t can be formed. The cross-sectional shape of the groove 26t can be a rectangular shape having substantially vertical side walls. Note that the depth of the groove 26t can be controlled by managing the etching time. Finally, the resist layer 55 is peeled off and the lower substrate 26 is cleaned.

[0036] Next, a plurality of openings 26a are formed in the back surface 26b of the lower substrate 26. This will be specifically described with reference to FIG. 9. FIG. 9 is a cross-sectional view taken along the line B-B of FIG. 4. A resist layer 60 is applied to the back surface 26b. Then, using well-known photolithography technology, a plurality of opening patterns 60p corresponding to the plurality of openings 26a are formed in the resist layer 60. Through the plurality of opening patterns 60p, anisotropic etching is performed so as to penetrate from the back surface 26b to the surface 26f. In this embodiment, DRIE is used. Thereby, a plurality of openings 26a can be formed. The cross-sectional shape of the opening 26a can be a rectangular shape having substantially vertical side walls.

[0037] The step of manufacturing the pedestal electrode in step S3 will be described with reference to FIGS. 10 - 12. FIGS. 10 - 12 are cross-sectional views at the same position as FIG. 3. As shown in FIG. 10, a resist layer 61 having an opening pattern 61p is formed on the surface 21f of the glass substrate 21. Through the opening pattern 61p, the surface 21f is wet-etched. Thereby, a ring groove 21r can be formed.

[0038] Next, the resist layer 61 is peeled off. An Al thin film is formed on the surface 21f, and the wiring 25 (see FIG. 1) is formed by a well-known patterning technique. Then, as shown in FIG. 11, the silicon substrate 22 is anodically bonded to the surface 21f, and the lower substrate 26 is anodically bonded to the back surface 21b. Since well-known techniques can be used for anodic bonding, detailed description thereof is omitted. In this embodiment, as the conditions for anodic bonding, a temperature of 350°C and an applied voltage of -700V to -1000V were used.

[0039] An Al thin film is formed on the surface 22f of the silicon substrate 22, and the electrode pads 23 and BR pads 24 are formed by a well-known patterning technique. Then, a resist layer 62 having an opening pattern 62p is formed on the surface 22f. Thereby, the structure shown in FIG. 11 is completed.

[0040] Through the opening pattern 62p, the silicon substrate 22 is trench-etched by DRIE technology. Thereby, as shown in FIG. 12, the annular electrode 22c, the divided electrode 22d, and the outer peripheral electrode 22o are formed. Also, the ring groove 21r and the wiring 25 previously formed on the glass substrate 21 can be exposed. Thus, the pedestal electrode 20 is completed.

[0041] The mounting process of the pedestal electrode in step S4 will be described. The die bonding material 50 is applied to the mounting surface 101 of the package 100. In this embodiment, the die bonding material 50 is applied to the entire die bonding region DR shown in FIG. 6. The back surface 26b of the pedestal electrode 20 fabricated in step S3 is pressed against the applied die bonding material 50. At this time, as shown in FIG. 6, the outer periphery of the lower substrate 26 and the outer peripheral contour of the die bonding region DR are positioned so as to substantially coincide.

[0042] When the pedestal electrode 20 is pressed, the die bonding material 50 enters the inside of the opening 26a. The amount of the die bonding material 50 entering the opening 26a can be appropriately controlled by the pressing pressure of the pedestal electrode 20. Then, a space SP is formed between the entered die bonding material 50 and the back surface 21b of the glass substrate 21 (see FIG. 3). The space SP communicates with the groove 26t at the overlapping portion OL. Thereby, the space SP and the groove 26t function as an exhaust path for outgas generated from the die bonding material 50.

[0043] Heat treatment is performed while the pedestal electrode 20 is being pressed. In this embodiment, heating is performed at 280° C. for 30 minutes or more. By baking the die bonding material 50 in this way, the pedestal electrode 20 can be fixed to the package 100. Further, heat treatment can promote outgas generation from the die bonding material 50. And the space SP formed in the opening 26a is not blocked by this heat treatment either.

[0044] The mounting process of the glass resonator in step S5 will be described. First, the paste 40 is applied inside the annular electrode 22c at the central portion of the pedestal electrode 20.

[0045] The glass resonator 30 produced in the above-described glass molding process (step S1) is held by a collet (not shown). Then, the bottom surface of the column portion 30p is inserted into the inside of the annular electrode 22c so that the central axis CA of the column portion 30p and the central axis CA of the annular electrode 22c coincide. The glass resonator 30 and the annular electrode 22c are mechanically and electrically connected by the paste 40. Then, heating is performed at 280° C. for 30 minutes or more to bake the paste 40. The electrode film formed on the surface of the glass resonator 30 and the outer peripheral electrode 22o are electrically connected via the paste 40 and the wiring 25 (see FIG. 1). Then, electrical connection is made between the electrode pad 23 and the BR pad 24 and the electrode 102 of the package 100 by the Au wire 110.

[0046] The vacuum hermetic sealing process in step S6 will be described with reference to the schematic cross-sectional view of FIG. 2. First, an upper electrode frame 123 having a rectangular frame shape is formed on the lid 130. The upper electrode frame 123 has a shape corresponding to the lower electrode frame 121 of the frame body 103. Next, the package 100 formed in the above-described mounting process is placed in a vacuum. A seal ring 122 having the same frame shape as the lower electrode frame 121 is installed on the lower electrode frame 121. The lid 130 is installed on the seal ring 122. At this time, the positions are adjusted so that the lower electrode frame 121, the seal ring 122, and the upper electrode frame 123 overlap each other.

[0047] Thereafter, heating is performed at 360° C. to perform a degassing process, and the sensor element 10 is hermetically sealed by eutectic bonding in a vacuum. At this time, a load may be applied to the lid 130 for pressing as necessary. Since hermetic sealing can be performed by the seal portion 120, the internal pressure of the package 100 can be maintained at a desired degree of vacuum.

[0048] (Effect) The problem will be described. The back surface 26b of the lower substrate 26 is adhesively fixed to the mounting surface 101 of the package 100 by the die bonding material 50. Gas is discharged from the die bonding material 50. However, if the gas cannot be sufficiently discharged from the die bonding material 50, outgassing may occur from the die bonding material 50 after vacuum hermetic sealing (step S6). As a result, it may be difficult to make the inside of the package 100 highly vacuum or to maintain a high vacuum state. Therefore, in the technology of this specification, an opening 26a and a groove 26t are formed in the lower substrate 26. Through the space SP of the opening 26a, the outgassing released from the inside of the die bonding material 50 can be guided to the groove 26t. Then, the outgassing can be efficiently exhausted to the outside through the groove 26t (see FIG. 3, arrow A1). Since the gas can be sufficiently discharged from the die bonding material 50, the outgassing can be completely removed before vacuum hermetic sealing. Since the outgassing generated from the die bonding material 50 after vacuum hermetic sealing can be suppressed, it is possible to achieve a high vacuum inside the package 100 and to maintain a high vacuum state.

[0049] As shown in FIG. 3, a part of the die bonding material 50 has penetrated from the back surface 26b side of the opening 26a into the inner side of the opening 26a. And a space SP that functions as a gas discharge path is formed. Thereby, the adhesive surface area between the die bonding material 50 and the back surface 26b can be increased by the amount of the die bonding material 50 that has entered the opening 26a. It becomes possible to achieve both strong adhesion and highly efficient gas discharge.

[0050] As shown in FIG. 4(A), the plurality of grooves 26t intersect the outer periphery of the lower substrate 26. Thereby, a plurality of outlets of the gas discharge path can be formed along the side 26y of the lower substrate 26. Therefore, it becomes possible to efficiently exhaust the outgas from the center side of the die bonding material 50 to the outside.

[0051] As shown in FIG. 4(C), in each of the plurality of openings 26a, the depth D1 is made equal to or greater than the width W1. Thereby, even when the die bonding material 50 penetrates into the opening 26a, the cross-sectional area of the space SP can be left sufficiently large. It becomes possible to achieve both strong adhesion and highly efficient gas discharge.

[0052] The gas generated from the die bonding material 50 is more likely to accumulate in the central part of the application area of the die bonding material 50 than in the peripheral part. In the present embodiment, as shown in FIG. 5, the density at which the openings 26a are formed is higher in the central region R1 of the lower substrate 26 than in the outer peripheral region R2. Thereby, it becomes possible to more efficiently exhaust the outgas accumulated in the central region of the die bonding material 50.

[0053] (Modification of Example 1) Although the case where the opening 26a is in the shape of a hole penetrating the lower substrate 26 in the thickness direction has been described, the present invention is not limited to this form. The opening 26a may be in the shape of a groove opening to the back surface 26b side and may have a bottom surface. In this case, the total value of the depth of the groove of the opening 26a and the depth of the groove 26t may be made larger than the thickness of the lower substrate 26. Thereby, in the overlapping portion OL formed at the intersection of the opening 26a and the groove 26t, the opening 26a and the groove 26t can be communicated with each other. It becomes possible to function as an outgas discharge path.

Example

[0054] If the plurality of openings 26a communicate with the plurality of grooves 26t, they can have various shapes and arrangements. In the second embodiment, the first mode and the second mode of the opening 26a are exemplified. Parts common to the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0055] (The first mode of the opening 26a) FIG. 13 shows the first mode of the opening 26a. FIG. 13 is the same drawing as FIG. 4 of the first embodiment. FIG. 13(B) is a cross-sectional view taken along line B-B. FIG. 13(C) is a cross-sectional view taken along line C-C. When viewed from the direction (z direction) perpendicular to the lower substrate 26, the plurality of grooves 26t and the plurality of openings 26a both extend in the x direction. That is, the longitudinal direction of the groove 26t and the longitudinal direction of the opening 26a are parallel to each other. Each of the plurality of openings 26a is formed to overlap with the corresponding groove 26t. The groove 26t has a width W21 in the short side direction. The opening 26a having a groove shape has a width W22 in the short side direction. The width W21 is larger than the width W22.

[0056] When the opening 26a and the groove 26t are parallel, the area where they intersect can be made larger than when they are orthogonal (Example 1). As shown in FIG. 13, by arranging the entire opening 26a within the formation region of the groove 26t, the entire opening 26a can be made to communicate with the groove 26t. Since the area of the communicating region can be maximized, the outgas discharge function can be enhanced more effectively.

[0057] Also, the width W21 of the groove 26t is made larger than the width W22 of the opening 26a. This makes it possible to ensure a manufacturing margin against misalignment in the y-direction position between the groove 26t and the opening 26a.

[0058] (Second aspect of the opening 26a) FIG. 14 shows the second aspect of the opening 26a. FIG. 14(B) is a cross-sectional view taken along line B-B. FIG. 14(C) is a cross-sectional view taken along line C-C. When viewed from a direction (z-direction) perpendicular to the lower substrate 26, the plurality of openings 26a have a circular hole shape. Each of the plurality of openings 26a is formed overlapping the corresponding groove 26t. The plurality of openings 26a are arranged at equal intervals in the x-direction and at equal intervals in the y-direction.

[0059] When the plurality of openings 26a are in a groove shape (Example 1), there is a dependency in the arrangement pattern of the openings 26a in the x-direction and the y-direction. As a result, an x-y direction difference may occur in the adhesive strength between the back surface 26b and the mounting surface 101. In this aspect, by making the plurality of openings 26a into a hole shape, the dependency in the x-y direction in the arrangement pattern of the openings 26a can be eliminated. It becomes possible to suppress the x-y direction difference in the adhesive strength.

Example

[0060] If the plurality of grooves 26t reach the outer periphery of the lower substrate 26 and communicate with the plurality of grooves 26t, they can have various shapes and arrangements. In Example 3, the first aspect and the second aspect of the grooves 26t are exemplified. Parts common to Example 1 and Example 3 are denoted by the same reference numerals and the description thereof is omitted.

[0061] (First aspect of groove 26t) FIG. 15 shows the first aspect of the groove 26t. FIG. 15 is the same drawing as FIG. 4(A) of Example 1. When viewed from a direction (z direction) perpendicular to the lower substrate 26, the plurality of grooves 26t extend parallel to the y-axis and also extend parallel to the x-axis. That is, the plurality of grooves 26t reach the ends of the lower substrate 26 in both the ±x direction and the ±y direction. Thereby, a plurality of outlets of the gas discharge path can be formed along the sides 26x and 26y of the lower substrate 26.

[0062] (Second aspect of groove 26t) FIG. 16 shows the second aspect of the groove 26t. FIG. 16 is the same drawing as FIG. 4(A) of Example 1. When viewed from a direction (z direction) perpendicular to the lower substrate 26, the plurality of grooves 26t include a circular part 26tc and a radial part 26tr. The circular part 26tc is a circular groove centered on the central axis CA of the lower substrate 26. The radial part 26tr is a groove extending radially in all directions from the central axis CA. Thereby, a gas discharge path can be formed in all directions around the central axis CA.

Example

[0063] In Example 4, an aspect in which a plurality of grooves are formed on the back surface 21b of the glass substrate 21 will be described. Parts common to Example 1 and Example 4 are denoted by the same reference numerals and the description thereof is omitted. FIG. 17(A) shows a bottom view of the glass substrate 21. FIG. 17(B) is a cross-sectional view taken along line B-B. FIG. 18(A) shows a top view of the lower substrate 26. FIG. 18(B) is a cross-sectional view taken along line B-B.

[0064] As shown in FIG. 17, a plurality of grooves 21t are formed on the back surface 21b of the glass substrate 21. The plurality of grooves 21t extend parallel to the x-axis. Further, as shown in FIG. 18, a plurality of openings 26a are formed in the lower substrate 26. The plurality of openings 26a extend parallel to the y-axis. The plurality of openings 26a penetrate the lower substrate 26 in the thickness direction (z direction). Note that no groove is formed on the surface 26f of the lower substrate 26.

[0065] (Method for manufacturing the gyro sensor 1) Using the flowchart of FIG. 7, the manufacturing process of the gyro sensor 1 of Example 4 will be described. Note that only the differences from Example 1 will be described. The formation process of the discharge path in step S2 will be described. First, a plurality of grooves 21t are formed on the back surface 21b of the glass substrate 21. Specifically, a resist layer having a plurality of opening patterns corresponding to the plurality of grooves 21t is formed on the back surface 21b. Through the plurality of opening patterns, the back surface 21b is wet-etched. In this example, a buffered hydrofluoric acid solution was used as the etching solution. As a result, as shown in FIG. 17(B), a plurality of grooves 21t can be formed. Since the wet etching is isotropic etching, the cross-sectional shape of the groove 21t is a round shape. Next, a plurality of openings 26a are formed in the lower substrate 26. Specifically, a resist layer having a plurality of opening patterns corresponding to the plurality of openings 26a is formed on the surface 26f. Through the plurality of opening patterns, anisotropic etching (DRIE) is performed.

[0066] The manufacturing process of the pedestal electrode in step S3 will be described. The surface 26f of the lower substrate 26 is anodic-bonded to the back surface 21b of the glass substrate 21. By this bonding, the lower surface of the groove 21t can be closed by the surface 26f. Also, at the intersection (overlapping portion OL) of the groove 21t and the opening 26a, the opening 26a and the groove 21t can be made to communicate with each other. The opening 26a and the groove 21t can constitute a discharge path for outgas discharged from the die bonding material 50.

[0067] (Modification of Example 4) If the plurality of grooves 21t formed on the back surface 21b of the glass substrate 21 reach the outer periphery of the glass substrate 21 and communicate with the plurality of openings 26a, they can have various shapes and arrangement modes. Therefore, the groove 26t (Example 1-3) formed on the front surface 26f of the lower substrate 26 can be replaced with the groove 21t (Example 4) formed on the back surface 21b of the glass substrate 21.

Example

[0068] In Example 5, various aspects of the die bond region DR will be described. Parts common to Example 1 and Example 5 are denoted by the same reference numerals, and the description thereof will be omitted. FIG. 19 shows the arrangement mode of the die bond region DR2 in Example 5. FIG. 19 is the same drawing as FIG. 6 of Example 1. Five die bond regions DR2 are formed in the lower substrate 26. The five die bond regions DR2 are arranged to be rotationally symmetric with respect to the central axis CA.

[0069] As described with reference to FIG. 6, the plurality of openings 26a extend in the ±y direction. The plurality of openings 26a intersect a part of the outer peripheral contour of each of the five die bond regions DR2. Thereby, an outlet of the gas discharge path can be formed in the outer peripheral contour of the five die bond regions DR2. It becomes possible to exhaust the outgas accumulated in the central portion of the five die bond regions DR2 from the outlet formed in the outer peripheral contour.

[0070] (Modification of Example 5) The shapes, numbers, and arrangement modes of the plurality of die bond regions can be various. The shape of the die bond region is not limited to a circular shape, and for example, it can be a ring shape or a lattice shape. Also, the number of die bond regions is not limited to five, and for example, it can be various numbers of dot-like regions such as nine points or sixteen points.

[0071] The specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Also, the technical elements described in this specification or the drawings exhibit technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Further, the technology illustrated in this specification or the drawings can achieve a plurality of objectives simultaneously, and achieving one of these objectives itself has technical utility.

[0072] (Modification example) The manufacturing process described with reference to FIG. 7 can be in various forms. For example, in the step of forming the discharge path (step S2), the order of forming the groove 26t and the opening 26a is not particularly limited. The groove 26t may be formed after the opening 26a is formed.

[0073] The planar shapes of the groove 26t and the opening 26a can be various. For example, the width of the groove may be changed continuously or stepwise. Also, the width of the groove may be made wider in the central region R1 than in the outer peripheral region R2. Thereby, it becomes possible to more efficiently exhaust the outgas accumulated in the central region of the die bonding material 50. Also, a combination of grooves having a plurality of different widths may be used.

[0074] The cross-sectional shapes of the groove 26t and the opening 26a can be various. For example, a rectangular shape with a constant width from the opening to the bottom surface, a forward taper shape where the width narrows from the opening to the bottom surface, a reverse taper shape where the width widens from the opening to the bottom surface, etc. may be used. By making the cross-section a rectangular shape or a reverse taper shape, it is possible to increase the cross-sectional area of the groove while maintaining a narrow width of the opening. Thereby, it becomes possible to achieve both an increase in the contact area and an increase in the gas discharge space.

[0075] The aspects of the present technology are listed below. [Aspect 1] A package configured to be hermetically sealable by a lid portion, A lower substrate stored in the package, the back surface of which is adhesively fixed to the mounting surface in the package, and a glass substrate disposed on the surface of the lower substrate, and an electrode portion disposed on the surface of the glass substrate, and a glass resonator including a tubular column portion having a central axis and a hollow substantially hemispherical peripheral portion centered on the central axis, the column portion being fixed to the electrode portion, and comprising a groove is formed on either the surface of the lower substrate or the back surface of the glass substrate, when viewed from a direction perpendicular to the lower substrate, the groove intersects at least one of the outer periphery of the lower substrate and the outer periphery of the glass substrate, an opening is formed on the back surface of the lower substrate, when viewed from a direction perpendicular to the lower substrate, the opening and the groove communicate with each other at an overlapping portion of the opening and the groove, a die bond material is disposed between the back surface of the lower substrate and the mounting surface, an inertial force sensor. [Aspect 2] the die bond material has penetrated from the back surface of the lower substrate to the inner side of the opening, The inertial force sensor according to Aspect 1, wherein a space is formed between the penetrating die bond material and the back surface of the glass substrate. [Aspect 3] when viewed from a direction perpendicular to the lower substrate, the groove extends in a first direction, The inertial force sensor according to Aspect 1 or 2, wherein the opening has a groove shape extending in a second direction orthogonal to the first direction. [Aspect 4] when viewed from a direction perpendicular to the lower substrate, the groove extends in a first direction, The inertial force sensor according to Aspect 1 or 2, wherein the opening has a groove shape extending in the first direction. [Aspect 5] The inertial force sensor according to aspect 4, wherein when viewed from a direction perpendicular to the lower substrate, the entire opening overlaps with the groove. [Aspect 6] The inertial force sensor according to any one of aspects 1-5, wherein the width of the groove in the short side direction is larger than the width of the opening having the groove shape in the short side direction. [Aspect 7] The inertial force sensor according to aspect 1, wherein when viewed from a direction perpendicular to the lower substrate, the opening has a hole shape. [Aspect 8] The inertial force sensor according to any one of aspects 1-7, wherein the depth of the opening is equal to or greater than the width of the opening. [Aspect 9] When viewed from a direction perpendicular to the lower substrate, the lower substrate and the glass substrate have a rectangular shape, The inertial force sensor according to any one of aspects 1-8, wherein the groove includes at least one of a portion parallel to the sides of the lower substrate and the glass substrate, a circular portion with respect to the center of the lower substrate and the glass substrate, or a radial portion extending from the center of the lower substrate and the glass substrate to the periphery. [Aspect 10] A package configured to be hermetically sealed by a lid, A lower substrate stored in the package, wherein the back surface of the lower substrate is adhesively fixed to the mounting surface in the package, A glass substrate disposed on the surface of the lower substrate, An electrode portion disposed on the surface of the glass substrate, A glass vibrator including a column portion having a central axis and a hollow substantially hemispherical peripheral portion centered on the central axis, wherein the column portion is fixed to the electrode portion, the glass vibrator, A method for manufacturing an inertial force sensor comprising: A step of forming a groove on either the surface of the lower substrate or the back surface of the glass substrate, An opening forming step of forming an opening on the back surface of the lower substrate, wherein when viewed from a direction perpendicular to the lower substrate, the opening and the groove communicate with each other in an overlapping portion of the opening and the groove; the opening forming step, A step of bonding the back surface of the glass substrate to the front surface of the lower substrate and bonding the electrode portion to the front surface of the glass substrate; A step of applying a die bonding material to the mounting surface of the package or the back surface of the lower substrate and then bringing the mounting surface into contact with the back surface of the lower substrate; A step of hermetically sealing the package with the lid; A method for manufacturing an inertial force sensor, comprising:

Explanation of reference numerals

[0076] 1: Gyro sensor 20: Pedestal electrode 21: Glass substrate 22: Silicon substrate 22c: Annular electrode 26: Lower substrate 26b: Back surface 26a: Opening 26t: Groove 30: Glass vibrator 30p: Column portion 30c: Peripheral portion 50: Die bonding material 100: Package 101: Mounting surface 130: Lid

Claims

1. A package configured to be hermetically sealed by a lid portion, A lower substrate stored in the package, wherein the back surface of the lower substrate is adhesively fixed to the mounting surface within the package, A glass substrate disposed on the surface of the lower substrate, An electrode portion disposed on the surface of the glass substrate, A glass resonator including a column portion having a central axis and a hollow substantially hemispherical peripheral portion centered on the central axis, wherein the column portion is fixed to the electrode portion, Comprising, A groove is formed on either the surface of the lower substrate or the back surface of the glass substrate, When viewed from a direction perpendicular to the lower substrate, the groove intersects at least one of the outer periphery of the lower substrate and the outer periphery of the glass substrate, An opening is formed on the back surface of the lower substrate, When viewed from a direction perpendicular to the lower substrate, the opening and the groove communicate with each other at the overlapping portion of the opening and the groove, A die bond material is disposed between the back surface of the lower substrate and the mounting surface, An inertial force sensor.

2. The die bond material has penetrated from the back surface of the lower substrate to the inner side of the opening, The inertial force sensor according to claim 1, wherein a space is formed between the penetrated die bond material and the back surface of the glass substrate.

3. When viewed from a direction perpendicular to the lower substrate, the groove extends in a first direction, The inertial force sensor according to claim 1, wherein the opening has a groove shape extending in a second direction orthogonal to the first direction.

4. When viewed from a direction perpendicular to the lower substrate, the groove extends in a first direction, The inertial force sensor according to claim 1, wherein the opening has a groove shape extending in the first direction.

5. The inertial force sensor according to claim 4, wherein when viewed from a direction perpendicular to the lower substrate, the entire opening overlaps with the groove.

6. The inertial force sensor according to any one of claims 3 to 5, wherein the width of the groove in the short side direction is larger than the width of the opening having the groove shape in the short side direction.

7. The inertial force sensor according to claim 1, wherein when viewed from a direction perpendicular to the lower substrate, the opening has a hole shape.

8. The inertial force sensor according to claim 1, wherein the depth of the opening is equal to or greater than the width of the opening.

9. When viewed from a direction perpendicular to the lower substrate, the lower substrate and the glass substrate have a rectangular shape, The inertial force sensor according to claim 1, wherein the groove includes at least one of a portion parallel to the sides of the lower substrate and the glass substrate, a circular portion with respect to the center of the lower substrate and the glass substrate, or a radial portion extending from the center of the lower substrate and the glass substrate to the periphery.

10. A package configured to be hermetically sealed by a lid, A lower substrate stored in the package, wherein the back surface of the lower substrate is adhesively fixed to the mounting surface in the package, A glass substrate disposed on the surface of the lower substrate, An electrode portion disposed on the surface of the glass substrate, A glass vibrator including a tubular column portion having a central axis and a hollow substantially hemispherical peripheral portion centered on the central axis, wherein the column portion is fixed to the electrode portion, the glass vibrator, A method for manufacturing an inertial force sensor comprising: A step of forming a groove on either the surface of the lower substrate or the back surface of the glass substrate; An opening forming step of forming an opening on the back surface of the lower substrate, wherein when viewed from a direction perpendicular to the lower substrate, the opening and the groove communicate with each other in an overlapping portion of the opening and the groove; the opening forming step; A step of bonding the back surface of the glass substrate to the surface of the lower substrate and bonding the electrode portion to the surface of the glass substrate; A step of applying a die bonding material to the mounting surface of the package or the back surface of the lower substrate and then bringing the mounting surface into contact with the back surface of the lower substrate; A step of hermetically sealing the package with the lid; A method for manufacturing an inertial force sensor, comprising the steps.

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