JP2008193175A - Piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and highly precise piezoelectric device capable of inputting/outputting control data. <P>SOLUTION: In the piezoelectric device 10, a piezoelectric vibrator piece 13 is mounted on a semiconductor substrate 11 on which a circuit element 12 is formed, the piezoelectric vibrator piece 13 and the circuit element 12 are electrically connected to each other via a through electrode 15. On the surface of the semiconductor substrate 11 on which the circuit element 12 is formed, an input/output terminal 17 for inputting control data to the circuit element 12 or outputting the characteristic data of the piezoelectric device 10 and an external connection terminal 16 to be used for connection with an external circuit board are electrically connected to the circuit element 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piezoelectric device.

  In recent years, with the enhancement of functions of portable devices, the demand for high stability and high accuracy of the piezoelectric devices used in such devices has increased, and in order to achieve high stability and high accuracy of piezoelectric devices. A piezoelectric device combining a piezoelectric vibrator and a circuit element has been used.

  In order to obtain such a highly stable and highly accurate piezoelectric device, for example, a piezoelectric device as disclosed in Patent Document 1 is disclosed. 3A and 3B are diagrams showing a structure of a conventional piezoelectric device, wherein FIG. 3A is a plan sectional view taken along line BB in FIG. 3B, and FIG. 3B is a side sectional view taken along line AA in FIG. FIG. Hereinafter, a conventional piezoelectric device will be described with reference to the drawings.

  In the piezoelectric device 100, a circuit pattern 102 of an integrated circuit element is formed on the lower surface of a package 101 made of a semiconductor substrate, and a cavity 103 for mounting the piezoelectric vibrating piece 107 is formed on the upper surface of the package 101. A piezoelectric vibrating piece 107 is mounted.

In the package 101, a mount electrode 106 for mounting the piezoelectric vibrating piece 107 is formed on the inner bottom surface of the cavity 103. The circuit pattern 102 is connected from the inner bottom surface of the cavity 103 to connect the mount electrode 106 and the circuit pattern 102. Through-hole electrodes 104 are formed. An external connection terminal 105 used for electrical connection between the circuit pattern 102 and the external circuit board is formed on the surface of the circuit pattern 102 formed on the lower surface of the package 101. As the circuit pattern 102, a pattern of a feedback amplifier circuit that operates the piezoelectric vibrating piece 107, a pattern of a temperature compensation circuit for reducing a change in frequency due to a change in ambient temperature, and an output frequency is changed by an external control voltage. The voltage control circuit pattern is formed.
In addition, an excitation electrode 108 and a connection electrode 109 are formed on the surface of the piezoelectric vibrating piece 107, and a piezoelectric material is obtained by bonding the mount electrode 106 and the connection electrode 109 formed on the package 101 with a conductive adhesive 110. The resonator element 107 and the circuit pattern 102 are connected.

  The piezoelectric device 100 is completed by mounting the lid body 111 on the opening of the cavity 103 with the piezoelectric vibrating piece 107 mounted in the cavity 103 of the package 101 in this way. The lid body 111 is made of a metal material such as Kovar or a glass material, and the lid body 111 is attached by applying the adhesive 112 to the entire periphery of the opening periphery of the cavity 103 and bonding the lid body 111. Do by. Note that, by mounting the lid 111 in a nitrogen atmosphere or a vacuum atmosphere, the inside of the cavity 103 is hermetically sealed in a nitrogen atmosphere or a vacuum atmosphere.

JP 2004-214787 A

In order to make the characteristics of piezoelectric devices highly stable and accurate, temperature-compensated piezoelectric devices that electrically correct the temperature characteristics of crystal resonators are widely used. In the piezoelectric device, it is necessary to input control data for compensating the temperature characteristic of the piezoelectric vibrating piece into the circuit element. As means for inputting the control data to the piezoelectric device, an input / output terminal for control data input / output electrically connected to a circuit element is formed on the surface of the piezoelectric device, and the control data is input from the input / output terminal. Is input to the circuit element. Further, the input / output terminal outputs characteristic data of the piezoelectric device obtained based on the control data input to the circuit element, and can be used for characteristic inspection.
Here, there is no description of means for inputting the control data to the circuit element for the piezoelectric device as shown in Patent Document 1 in which the piezoelectric vibrating piece is mounted on the package in which the circuit element is formed on the semiconductor substrate. A configuration for realizing a highly accurate piezoelectric device such as a temperature compensation type is not sufficiently disclosed.
Therefore, the present invention is to provide a small and highly accurate piezoelectric device capable of inputting / outputting control data in a piezoelectric device in which a piezoelectric vibrating piece is mounted on a semiconductor substrate on which circuit elements are formed.

  In order to achieve the above object, a piezoelectric device of the present invention has a piezoelectric vibrating piece mounted on a first main surface of a semiconductor substrate, and a second main surface of the semiconductor substrate on which the piezoelectric vibrating piece is not mounted. A circuit element is formed, and the piezoelectric vibrating piece and the circuit element are electrically connected by a through electrode that penetrates the semiconductor substrate and connects the first main surface and the second main surface, An input / output terminal for inputting control data to the circuit element or outputting characteristic data of the piezoelectric device and an external connection used for connection to an external circuit board are provided on the second main surface side of the semiconductor substrate. A terminal is formed so as to be electrically connected to the circuit element, and a lid is attached to the first main surface of the semiconductor substrate to seal the piezoelectric vibrating piece.

  Further, a multilayer wiring layer including a wiring electrically connected to the circuit element is formed on the circuit element, and the input / output terminal and the external connection terminal are connected via a predetermined wiring of the multilayer wiring layer. The piezoelectric device is connected to the circuit element.

  Further, an insulating layer is formed on the surface portion of the predetermined wiring of the multilayer wiring layer connected to the input / output terminal so as to cover the wiring except for a part thereof, and the wiring not covered by the insulating layer The piezoelectric device according to claim 3, wherein the piezoelectric device is the input / output terminal.

  Furthermore, the surface of the input / output terminal is a piezoelectric device positioned on the semiconductor substrate side with respect to the surface of the external connection terminal.

  Furthermore, the input / output terminals and the external connection terminals are piezoelectric devices whose surfaces are formed of different materials.

  The surface of the external connection terminal is gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), copper The piezoelectric device is made of a material mainly composed of at least one of (Cu).

  The input / output terminal is a piezoelectric device whose surface is made of a material mainly composed of at least one of aluminum (Al), titanium (Ti), chromium (Cr), and nickel (Ni).

  The semiconductor substrate has a flat plate shape, and a piezoelectric device in which a lid having a recess for covering the piezoelectric vibrating piece is attached to a first main surface of the semiconductor substrate and the piezoelectric vibrating piece is sealed To do.

  According to the present invention, a small and highly accurate piezoelectric device capable of inputting and outputting control data can be realized.

  The best embodiment of the present invention will be described with reference to FIGS.

  1A and 1B are diagrams showing the structure of a piezoelectric device according to an embodiment of the present invention. FIG. 1A is a plan sectional view taken along line AA in FIG. 1B, and FIG. It is side surface sectional drawing in a line, (c) is a bottom view.

  Reference numeral 11 denotes a flat semiconductor substrate 11 mainly composed of silicon. A circuit element 12 having a circuit pattern for driving the piezoelectric vibrating reed 13 and controlling oscillation is formed on the first main surface of the semiconductor substrate 11, and the main surface of the semiconductor substrate 11 on which the circuit element 12 is formed. A mount electrode 14 for mounting the piezoelectric vibrating reed 13 is formed on the other main surface opposite to. The circuit element 12 and the mount electrode 14 are electrically connected by a through electrode 15 that penetrates the semiconductor substrate 11. On the circuit element 12, a multilayer wiring layer 23 composed of a wiring electrically connected to the circuit element 12 and an insulating layer is formed, and connected to the circuit element 12 and connected to the external circuit board and the circuit element 12. An external connection terminal 16 used for connection and an input / output terminal 17 for inputting control data of the piezoelectric vibrating piece 13 to the circuit element 12 or outputting characteristics of the piezoelectric vibrating piece 13 are formed.

An excitation electrode 18 and a connection electrode 19 are formed on the surface of the piezoelectric vibrating reed 13 by means such as vapor deposition, and the mount electrode 14 formed on the semiconductor substrate 11 is electrically and mechanically electrically conductively bonded to the mount electrode 14. It is connected. The piezoelectric vibrating piece 13 and the mount electrode 14 are connected using the conductive adhesive 20 here, but may be connected by, for example, metal bumps.
After mounting the piezoelectric vibrating piece 13 on the semiconductor substrate 11 in this manner, the lid 22 having the recess 21 is joined to the semiconductor substrate 11 so as to cover the piezoelectric vibrating piece 13, thereby completing the piezoelectric device 10. As the lid 22, a metal lid or a silicon lid can be applied. As a joining method, a method of applying and bonding an adhesive to the entire periphery of the opening peripheral edge of the lid 22, or the semiconductor substrate 11. Bonding is performed by providing Au—Sn at the bonding interface between the substrate 22 and the lid 22 and heating and melting it, or by surface activation bonding in which the bonding surface of the semiconductor substrate 11 and the lid 22 is activated and bonded. To do.

  Here, the external connection terminal 16 is a terminal used for connecting an external circuit board after the piezoelectric device 10 is completed as a product. The input / output terminal 17 is an input of control data to the circuit element 12 or a piezoelectric device. This is a terminal that becomes unnecessary in practice after the characteristic inspection of 10. Therefore, when the input / output terminal 17 is exposed to the mounting surface of the semiconductor substrate 11 using the same material as the external connection terminal 16, the piezoelectric device 10 is externally connected to the external surface using solder or the like. When mounting on a circuit board or the like, solder also adheres to the input / output terminal 17 and short-circuits with the external connection terminal 16, resulting in an abnormal connection state as a circuit for operating the piezoelectric device 10, and unnecessary electrical For example, a signal is input to the circuit element to cause deterioration of the characteristics of the piezoelectric device 10. However, in the present invention, the surface of the external connection terminal 16 is chemically stable and easily wet with solder, such as gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium ( Ru), iridium (Ir), osmium (Os), copper (Cu) are composed of a material mainly composed of at least one kind, and the surface of the input / output terminal 17 is chemically active and easily oxidized. The external connection terminal 16 can be stably and electrically made of a material mainly composed of at least one of aluminum (Al), titanium (Ti), chromium (Cr), and nickel (Ni) that is difficult to wet. In addition to being mechanically connected and fixed, there is no short circuit between the external connection terminal 16 and the input / output terminal 17, so a highly reliable piezoelectric device that does not cause malfunction or the like. It is possible to provide a chair 10. The external connection terminals 16 and the input / output terminals 17 are formed using a technique such as film formation such as coating, printing, plating, sputtering, vapor deposition, or aerosol deposition in which fine particles are sprayed.

  FIG. 2 is an enlarged partial cross-sectional view illustrating an example of a multilayer wiring layer that connects the input / output terminals and the external output terminals and the circuit elements according to the embodiment of the present invention. As shown in FIG. 2A, the plurality of electrode pads 24 included in the circuit element 12 are respectively connected to the wiring 25, and the wiring 25 is covered with an insulating material 26 in order to maintain insulation from the circuit pattern of the circuit element 12. However, the insulating material 26 corresponding to the input / output terminals 17 and the external connection terminals 16 is removed, and the wiring 25 can be electrically connected to the outside.

  FIG. 2A shows a case where the wiring 25 is formed of a chemically active material such as Al, and the input / output terminal 17 is formed using the portion of the wiring 25 from which the insulating material 26 is removed as it is. The external connection terminal 16 is formed by laminating a terminal material A27 made of a chemically stable material such as Au on the portion of the wiring 25 where the insulating material 26 is removed. That is, the surface of the external connection terminal 16 is made of a material that is chemically stable and easily wets with solder, and the surface of the input / output terminal 17 is made of a material that is chemically active and easily oxidized and hardly wets with solder. Thus, when mounting a piezoelectric device on an external circuit board or the like, the external connection terminal 16 is stably and electrically connected and fixed, and a short circuit between the external connection terminal 16 and the input / output terminal 17 occurs. Therefore, it is possible to provide a highly reliable piezoelectric device that does not cause malfunction or the like. Further, as shown in FIG. 2B, the input / output terminal 17 is formed by further laminating a terminal material B28, which is a chemically active material, on the portion of the wiring 25 where the insulating material 26 is removed. There is no problem.

Further, FIG. 2A shows the case where the wiring 25 is formed of a material that is chemically active and difficult to wet with solder. In the structure of FIG. Since the input / output terminal 17 is formed by laminating the terminal material B28, which is a chemically active material, on the portion where the insulating material 26 of 25 is removed, a chemically stable material is used for the wiring 25. Is also possible.
The input / output terminal 17 is positioned on the semiconductor substrate 11 side (the surface side on which the piezoelectric vibrating piece 13 is mounted) with respect to the surface of the external connection terminal 16. For this reason, it has a structure in which the possibility of occurrence of a short circuit between the external connection terminal 16 and the input / output terminal 17 is further suppressed.

  The present invention can be utilized for a small piezoelectric device.

It is a figure which shows the structure of the piezoelectric device in one Example of this invention, (a) is a plane sectional view in the AA line of (b), (b) is the side surface in the BB line of (c). It is sectional drawing, (c) is a bottom view. FIG. 4 is an enlarged partial cross-sectional view illustrating an example of a multilayer wiring layer that connects the input / output terminals and external output terminals of the embodiment of the present invention to circuit elements. It is a figure which shows the structure of the piezoelectric device in a prior art example, (a) is a plane sectional view in the BB line of (b), (b) is a side sectional view in the AA line of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Piezoelectric device 11 Semiconductor substrate 12 Circuit element 13 Piezoelectric vibration piece 14 Mount electrode 15 Through electrode 16 External connection terminal 17 Input / output terminal 18 Excitation electrode 19 Connection electrode 20 Conductive adhesive 21 Recess 22 Lid 22 Lid 23 Multilayer wiring layer 24 Electrode pad 25 Wiring 26 Insulating material 27 Terminal material A
28 Terminal material B
DESCRIPTION OF SYMBOLS 100 Piezoelectric device 101 Package 102 Circuit pattern 103 Cavity 104 Through-electrode 105 External connection terminal 106 Mount electrode 107 Piezoelectric vibrating piece 108 Excitation electrode 109 Connection electrode 110 Conductive adhesive 111 Cover body 112 Adhesive

Claims (8)

In a piezoelectric device in which a piezoelectric vibrating piece is housed in an internal space of a package composed of a semiconductor substrate and a lid,
The piezoelectric vibrating piece is mounted on the first main surface of the semiconductor substrate,
A circuit element is formed on the second main surface of the semiconductor substrate on which the piezoelectric vibrating piece is not mounted,
The piezoelectric vibrating piece and the circuit element are electrically connected by a through electrode that penetrates the semiconductor substrate and connects the first main surface and the second main surface,
On the second main surface side of the semiconductor substrate, an input / output terminal for inputting control data to the circuit element or outputting characteristic data of the piezoelectric device, and an external used for connection to an external circuit substrate A connection terminal is formed to be electrically connected to the circuit element;
Attaching a lid to the first main surface of the semiconductor substrate and sealing the piezoelectric vibrating piece;
A piezoelectric device characterized by the above.   A multilayer wiring layer including a wiring electrically connected to the circuit element is formed on the circuit element, and the input / output terminal and the external connection terminal are connected to each other via a predetermined wiring of the multilayer wiring layer. The piezoelectric device according to claim 1, wherein the piezoelectric device is connected to a circuit element.   An insulating layer is formed on the surface portion of the predetermined wiring of the multilayer wiring layer connected to the input / output terminal so as to cover the wiring except for a part, and the wiring not covered by the insulating layer is in front. The piezoelectric device according to claim 2, wherein the piezoelectric device is a writing output terminal.   The surface of the said input / output terminal is located in the said semiconductor substrate side with respect to the surface of the said external connection terminal, The piezoelectric device of any one of Claims 2-3 characterized by the above-mentioned.   5. The piezoelectric device according to claim 2, wherein surfaces of the input / output terminals and the external connection terminals are made of different materials. 6.   The surface of the external connection terminal is gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os), copper The piezoelectric device according to claim 5, wherein the piezoelectric device is made of a material mainly composed of at least one of (Cu).   The input / output terminal has a surface made of a material mainly composed of at least one of aluminum (Al), titanium (Ti), chromium (Cr), and nickel (Ni). Item 7. The piezoelectric device according to any one of Items 5 and 6.   The semiconductor substrate has a flat plate shape, and a lid body having a recess for covering the piezoelectric vibrating piece is attached to a first main surface of the semiconductor substrate to seal the piezoelectric vibrating piece. The piezoelectric device according to any one of claims 1 to 7.

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