JP2006162628A - Sensor system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce temperature drift in sensor characteristics. <P>SOLUTION: The sensor system 101 comprises a sensor device 10 and an integrated circuit 20 for driving the sensor device 10. The sensor device 10 comprises an upper sealing body 2 including silicon as a substrate as a sensor body section 1 including silicon as the substrate, and a lower sealing body 3. The integrated circuit 20 for driving the sensor device 10 forms a laminate with the sensor device 10. The sensor body section 1 is electrically connected to a wiring pattern 12 of the integrated circuit 20 through a through-cable run 4 that penetrates the upper sealing body 2 and an electrode 5 for mounting, disposed on the outer surface of the upper sealing body 2. The sensor device 10 is connected to an MID substrate 30 through the integrated circuit 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensor system including a sensor device and an integrated circuit for driving the sensor device, and more particularly to a sensor system capable of reducing temperature drift in sensor characteristics.

  A micro system in which micro-sized sensors, actuators, and the like using micro-machine technology based on semiconductor processes and their drive circuits (including control circuits) are integrated is called MEMS (Micro Electro Mechanical System). .

  FIG. 4 is a side cross-sectional view of a conventional sensor system formed as a MEMS. The sensor system 150 includes a ceramic substrate 70, a sensor device 74, an integrated circuit 75, a mounting external electrode 77, and a sealing material 78. The ceramic substrate 70 has a wiring pattern 76.

  The sensor device 74 is an angular velocity sensor, and includes a sensor main body 71 made of silicon as a base material, an upper sealing body 72 made of glass, and a lower sealing body 73 also made of glass. The upper sealing body 72 and the lower sealing body 73 are members that house the sensor main body 71 in an airtight manner. The integrated circuit 75 is a drive circuit that drives (including control) the sensor device 74, and is connected to the wiring pattern 76 on the ceramic substrate 70 through bumps in the form of a bare chip. That is, the integrated circuit 75 is flip-chip mounted on the ceramic substrate 70. The sensor device 74 is also mounted on the ceramic substrate 70 in the same manner as flip chip mounting. The sensor device 74 and the integrated circuit 75 are sealed with a resin sealing material 78. The sensor system 150 can be mounted on an external circuit board or the like through the mounting external electrode 77 connected to the wiring pattern 76. Thus, the sensor system 150 can be handled as if it were one integrated circuit.

As for the sensor device 74, as disclosed in Patent Document 1, the technology for sealing the sensor main body 71 based on silicon with the upper sealing body 72 and the lower sealing body 73 made of glass is as follows. This is a technique commonly used in this field. However, there is a problem that the difference in coefficient of thermal expansion is large between silicon and glass, and the sensor main body 71 is distorted as the temperature changes. This distortion has caused a temperature drift in the characteristics of the sensor by changing the resonance frequency of the sensor main body 71 or the like. Furthermore, since the sensor system 150 is mounted so that the sensor device 74 and the integrated circuit 75 are arranged side by side, there is a limit to downsizing the system.
JP 2001-153881 A

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a sensor system in which temperature drift in sensor characteristics is reduced.

  In order to solve the above problems and achieve the above object, a sensor system according to a first aspect of the present invention includes a lower sealing body formed from one wafer and a wafer different from the one wafer. A sensor main body to be formed; and an upper sealing body formed from another wafer different from the one wafer and the other wafer; and by cutting the individual wafers after joining the three wafers In order to drive the obtained sensor device in which the lower sealing body, the sensor main body and the upper sealing body are made of the same material, and the sensor device connected to the sensor device to form a laminated body An integrated circuit, an MID substrate that supports the stacked body without being interposed between the sensor device and the integrated circuit, and the sensor device and the integrated circuit provided on the MID substrate through the MID substrate. It is characterized in further comprising at least one electrically connected to have been implemented for the external electrodes of the circuit.

  According to a second aspect of the present invention, there is provided a sensor system according to the first aspect, wherein the material is a semiconductor.

  According to a third aspect of the present invention, there is provided a sensor system according to the first or second aspect, wherein the mounting external electrode is a pin bent in a step shape. .

  In the sensor system of the present invention, since the lower sealing body, the sensor main body, and the upper sealing body in the sensor device are made of the same material, there is no difference in thermal expansion coefficient between these members. For this reason, the temperature drift resulting from the difference in the thermal expansion coefficient between these members is suppressed in the sensor system. In addition, the sensor system can be miniaturized because the sensor device and the integrated circuit are in a stacked state.

(First embodiment)
FIG. 1 is a cross-sectional view showing a configuration of a sensor system according to a first embodiment of the present invention. FIG. 1A is a vertical cross-sectional view of the sensor system, and FIG. 1B is a cross-sectional view taken along the line AA in FIG. The sensor system 101 is formed as a MEMS, and includes a sensor device 10, an integrated circuit 20, a MID (Molded Interconnect Device) substrate 30, a mounting external electrode 31, and a sealing material 32. The sensor device 10 is, for example, an angular velocity sensor, and includes a sensor main body 1 that uses silicon as a base material, an upper sealing body 2 that also uses silicon as a base material, and a lower sealing body 3 that also uses silicon as a base material. ing. The phrase “based on silicon” is intended to include silicon doped with impurities.

  The upper sealing body 2 and the lower sealing body 3 are bonded to each other so that the sensor main body 1 is hermetically accommodated in a cavity formed therein. The upper sealing body 2 and the lower sealing body 3 can be bonded using a well-known silicon substrate bonding technique. A mounting electrode 5 for mounting the sensor device 10 is provided on the outer surface of the upper sealing body 2. The mounting electrode 5 is a bump electrode, for example, and is electrically connected to the sensor main body 1 by a through electrical path 4 that is a conductor that penetrates the upper sealing body 2.

  The lower sealing body 3 includes a substrate-like member 35 and a frame-like member 36 joined thereto. The substrate-like member 35 can be formed from one wafer, the sensor body 1 and the frame-like member 36 can be formed from another wafer, and the upper sealing body 2 can be formed from another wafer. The sensor device 10 can be obtained by performing processing for forming the through-electric path 4 on each wafer, joining the three wafers by bonding, for example, and then cutting them into individual chips. In each figure after FIG. 1, the frame-shaped member 36 is included in the lower sealing body 3, but may be included in the upper sealing body 2.

  The integrated circuit 20 is a drive circuit that drives (including control) the sensor device 10 and is connected to the sensor device 10 through the mounting electrodes 5 in the form of a bare chip to form a two-layer laminate. The integrated circuit 20 includes a chip body 11 that is an integrated circuit substrate, and a wiring pattern 12 formed on one main surface thereof, and the mounting electrode 5 is connected to the wiring pattern 12. The stacked body of the sensor device 10 and the integrated circuit 20 is supported by the MID substrate 30 in a state of being inserted into a recess provided in the MID substrate 30. Further, the laminate is sealed with a sealing material 32 such as a resin.

  The MID substrate (three-dimensional circuit forming substrate) 30 includes a substrate body 21 made of an insulator formed by molding a resin or the like, and a wiring pattern 22 disposed on the surface thereof. . An external electrode 31 for mounting for mounting the sensor system 101 on an external circuit board is connected to the wiring pattern 22. The wiring pattern 12 of the integrated circuit 20 is connected to the wiring pattern 22 through a mounting electrode 23 for mounting the integrated circuit 20. Thereby, the laminate and the mounting external electrode 31 are electrically connected. The mounting electrode 23 is, for example, a bump electrode. In this way, the sensor system 101 can be handled as if it were one integrated circuit.

  As described above, in the sensor system 101, the sensor main body 1 is housed and fixed by the upper sealing body 2 and the lower sealing body 3 having the same material as that of the sensor system 101. There is no difference in thermal expansion coefficient. For this reason, the temperature drift of the sensor characteristic resulting from the difference of the thermal expansion coefficient between the structural members of the sensor apparatus 10 is eliminated. Since the integrated circuit 20 and the upper sealing body 2 are interposed between the sensor main body 1 and the MID substrate 30, temperature drift due to the difference in thermal expansion coefficient between the MID substrate 30 and the sensor device 10 is also low. It can be suppressed. Thereby, highly accurate sensor characteristics can be obtained.

  Moreover, since the sensor main body 1 and the mounting electrode 5 are connected by the through-electric path 4 penetrating the upper sealing body 2, the sensor device 10 realizes the same form as the flip chip of the integrated circuit. The sensor device 10 is reduced in size without spreading horizontally. Since the upper sealing body 2 uses silicon as a base material, it can be finely processed in the same manner as the sensor main body 1, which facilitates the formation of the through current path 4.

  Furthermore, since the sensor device 10 and the integrated circuit 20 form a stacked body, the sensor system 101 can be formed in a small size. The integrated circuit 20 is mounted on the MID substrate 30 in the form of a flip chip, which also contributes to the downsizing of the sensor system 101.

  Further, since the MID substrate 30 is used, the mounting external electrode 31 can be easily formed. Further, as shown in FIG. 1, the mounting external electrode 31 is formed as a pin bent in a staircase shape, so that the circuit board (for example, a motherboard) on which the sensor system 101 is mounted and the sensor system 101 are arranged. The thermal strain generated in the sensor system 101 due to the difference in thermal expansion coefficient is reduced. Thereby, the influence of the thermal strain on the sensor characteristics is further suppressed.

  FIG. 2 is a manufacturing process diagram illustrating a process of forming the through-electric path 4 in the upper sealing body 2. In order to form the through current path 4 in the upper sealing body 2, first, the through hole 42 is formed in the upper sealing body 2 by using, for example, ICP, and then the silicon dioxide insulating film 41 is formed by, for example, thermal oxidation. It forms on the surface of the sealing body 2 (FIG. 2 (a)). Next, by using CVD (Chemical Vapor Deposition), a conductor 43 such as copper is deposited on the surface of the upper sealing body 2 (FIG. 2B). The conductor 43 may be a metal other than copper, or may be polycrystalline silicon doped with impurities. Thereafter, for example, copper plating is performed to deposit the conductor 44, thereby filling the through hole 42 with the conductor 44 (FIG. 2C). CVD may be used instead of copper plating. Next, for example, metal RIE (reactive ion etching) is performed using a mask pattern, and wiring patterns (including pads) 46 and 47 are formed by selectively removing the conductor 44 (FIG. 2D). )).

  Thus, the through-electric path 4 can be easily formed in the upper sealing body 2 by combining known semiconductor processes. 2C, the through hole 42 can be easily embedded with the conductor 44, so that the upper sealing body 2 and the lower sealing body 3 are disposed inside to accommodate the sensor main body 1. The storage chamber formed can be easily kept airtight, and in particular, can be kept at a high vacuum. Thereby, the sensor device 10 with good quality can be obtained. Furthermore, since the insulating film 41 is formed on the surface of the upper sealing body 2, the upper sealing body 2 made of silicon as a base material and the through current path 4 are electrically insulated well. Thereby, a highly accurate sensor device 10 is obtained.

  Further, as shown in FIG. 2D, the lower sealing body 3 can be easily bonded to the lower sealing body 3 by forming the lower surface of the upper sealing body 2 flat. In addition, instead of the upper sealing body 2 or in combination therewith, it is possible to form the through-electric path 4 in the lower sealing body 3.

  In addition, the sensor main body 1, the upper sealing body 2, and the lower sealing body 3 may be semiconductors other than a silicon-based material. However, among many semiconductors, a technique for performing microfabrication is widely established for silicon, and the material is also low in cost, so that a silicon-based material is particularly desirable. Further, even if the sensor body 1, the upper sealing body 2, and the lower sealing body 3 are not made of a semiconductor material, the temperature drift problem caused by the difference in thermal expansion coefficient can be solved if the materials are the same. Is done. However, by using a semiconductor as a material, microfabrication can be easily performed using a semiconductor process, and the highly accurate and small sensor device 10 and sensor system 101 can be easily obtained.

(Second Embodiment)
FIG. 3 is a longitudinal sectional view showing a configuration of a sensor system according to the second embodiment of the present invention. This sensor system 103 is mainly different from the sensor system 101 shown in FIG. 1 in that the base end portion of the mounting external electrode 31 is embedded in the substrate main body portion 21 of the MID substrate 30. Also in the sensor system 103, as in the sensor system 101, the mounting external electrode 31 is formed as a pin bent in a staircase shape, so that heat between the circuit board on which the sensor system 103 is mounted and the sensor system 103 is formed. The thermal strain generated in the sensor system 103 due to the difference in the expansion coefficient is reduced, and the deterioration of the sensor characteristics due to the thermal strain is suppressed.

  In order to embed the mounting external electrode 31 in the substrate main body 21, a lead frame (not shown) for connecting a large number of mounting external electrodes 31 is prepared, and the material of the substrate main body 21 such as resin is molded together with the lead frame. (Mold). After the molding of the substrate main body 21 is finished, the mounting external electrode 31 is separated from the lead frame and further formed in a step shape, whereby the mounting external electrode 31 having the shape of FIG. 3 can be easily obtained.

It is a longitudinal section showing the composition of the sensor system by a 1st embodiment of the present invention. It is a manufacturing process figure which shows the process of forming a penetration electric circuit in the upper sealing body of FIG. It is a longitudinal cross-sectional view which shows the structure of the sensor system by the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the sensor system by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor main-body part 2 Upper sealing body 3 Lower sealing body 4 Through electrical circuit 5, 23 Mounting electrode 10 Sensor apparatus 11 Chip body (integrated circuit board)
DESCRIPTION OF SYMBOLS 12 Wiring pattern 20 Integrated circuit 30 MID board 31 External electrode for mounting 41 Insulating film 42 Through-hole 43, 44 Conductor 101-103 Sensor system

Claims (3)

A lower sealing body formed from one wafer, a sensor body formed from a wafer different from the one wafer, and a wafer further formed from the one wafer and the other wafer. A sensor having the same material as the lower sealing body, the sensor main body, and the upper sealing body, which are obtained by individually cutting the three wafers after joining the three wafers. Equipment,
An integrated circuit for driving the sensor device, connected to the sensor device to form a laminate;
An MID substrate that supports the stacked body without being interposed between the sensor device and the integrated circuit;
A sensor system comprising: a mounting external electrode provided on the MID substrate and electrically connected to at least one of the sensor device and the integrated circuit through the MID substrate. The sensor system according to claim 1, wherein the material is a semiconductor. The sensor system according to claim 1, wherein the external electrode for mounting is a pin bent in a step shape.

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