JP2008122134A - Acceleration sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an impact resistance in an acceleration sensor apparatus for extracting an electrical signal from a sensing section for outputting the electrical signal corresponding to an applied acceleration through a plurality of wires. <P>SOLUTION: The acceleration sensor apparatus is provided with: the sensing section 10 for outputting the electrical signal corresponding to the applied acceleration; and a plurality of the wires 40 electrically connected to the sensing section, and extracting the electrical signal. A plurality of the wires 40 are fixed by an insulating member 50, and spaced at a regular interval. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an acceleration sensor device having a sensing unit that outputs an electrical signal corresponding to an applied acceleration.

  Conventionally, as this type of acceleration sensor device, a device in which a movable portion that is displaced by acceleration is formed on one surface side of a semiconductor substrate has been proposed (for example, see Patent Document 1).

  Such an acceleration sensor device is provided with a circuit chip made of an IC chip or the like separate from the sensor chip for the purpose of processing a signal output from the sensor chip. In that case, for the purpose of reducing the size of the sensor device, a configuration in which these sensor chips and circuit chips are stacked and these two chips are electrically connected, a so-called stack structure is employed.

  FIG. 4 is a diagram showing a general schematic cross-sectional configuration of a sensor device in which such a sensor chip and a circuit chip are laminated. In the sensor device shown in FIG. 4, the circuit chip 20 is fixed inside the package 30 sealed with the lid 32 via an adhesive 91, and an adhesive sheet 91 or the like is placed on the circuit chip 20. A sensor chip 10 having an acceleration detection unit 11 is mounted and fixed in a stacked form.

The sensor chip 10 and the circuit chip 20 and the circuit chip 20 and the package 30 are electrically connected via a wire 40 formed by wire bonding or the like.
JP 2004-286615 A

  In the sensor device as shown in FIG. 4, since the interval between the plurality of wires connecting the sensor chip and the circuit chip is relatively narrow, a minute parasitic capacitance is generated between the wires. Therefore, when the wire connecting the sensor chip and the circuit chip is deformed due to an impact applied to the sensor device from the outside, there is a problem that the parasitic capacitance between the wires changes to change the characteristics of the sensor output. .

  The present invention has been made in view of the above problems, and an object of the present invention is to improve impact resistance in an acceleration sensor device that extracts an electric signal through a plurality of wires from a sensing unit that outputs an electric signal corresponding to an applied acceleration. And

  A first feature of the present invention is that a sensing unit (10) that outputs an electrical signal corresponding to an applied acceleration, and a plurality of wires (40) that are electrically connected to the sensing unit and take out the electrical signal. The plurality of wires are fixed by an insulating member (50), and the interval between the plurality of wires is kept constant.

  In such a configuration, even if an impact is applied from the outside, the plurality of wires connected to the sensing unit are fixed by the insulating member (50), and the interval between the plurality of wires is kept constant. Impact properties can be improved.

  The insulating member can be made of a resin adhesive, foamed urethane, or a tape member.

  In addition, the second feature of the present invention is that the sensing unit has a chip shape in which a plurality of pads (12) for outputting electrical signals corresponding to acceleration are formed, and a plurality of pads are formed on the chip. These wires (40) are connected, and the plurality of wires are fixed on the chip by an insulating member (50).

  As described above, the plurality of wires can be fixed on the chip by the insulating member.

  A third feature of the present invention includes a circuit chip (20) that processes an electrical signal from the sensing unit (10), and the sensing unit (10) is stacked on the circuit chip (20), and includes a plurality of The wire (40) is connected to the circuit chip, and the insulating member (50) is fixing a plurality of wires on the circuit chip.

  In this manner, the sensing unit can be stacked on the circuit chip, the plurality of wires are connected to the circuit chip, and the insulating member can fix the plurality of wires on the circuit chip.

  A fourth feature of the present invention is that a film member (60) that absorbs stress generated by thermal strain of the circuit chip (20) is provided between the sensing unit (10) and the circuit chip (20). That is.

  In order to improve the impact resistance, for example, if the entire acceleration sensor device including the sensing unit and the circuit chip is sealed with a resin mold, the impact resistance can be improved. Stress is applied to the sensing portion due to thermal expansion of the resin mold, and the characteristics of the sensor output change. Here, since the film member provided between the sensing unit and the circuit chip absorbs the stress caused by the thermal distortion of the circuit chip, it is possible to suppress changes in the sensor output characteristics due to temperature changes.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

  FIG. 1 shows a schematic top view of an acceleration sensor device according to an embodiment of the present invention. FIG. 2 shows a schematic sectional configuration of the acceleration sensor device. FIG. 1 shows a state where the lid 32 in FIG. 2 is removed.

[Configuration]
The acceleration sensor device 100 mainly includes a sensor chip 10 as a sensing unit as an acceleration detecting element, a circuit chip 20, a ceramic package 30 that houses both the chips 10 and 20, and the members 10 and 20 respectively. , 30 is provided with a bonding wire 40 that electrically connects between them.

  As shown in FIG. 2, the circuit chip 20 and the sensor chip 10 are sequentially stacked on the ceramic package 30. Here, the ceramic package 30 and the circuit chip 20 are bonded and fixed by an adhesive (not shown) such as an epoxy resin or a silicon resin. The circuit chip 20 and the sensor chip 10 are bonded and fixed via a film-like adhesive film 60 such as NCF (Non Contact Film). The adhesive film 60 in this embodiment is made of a flexible material, that is, a material having a low Young's modulus.

  By disposing the adhesive film 60 having such flexibility between the circuit chip 20 and the sensor chip 10, the stress to the sensor chip 10 due to the thermal strain of the circuit chip 20 at the time of temperature change is absorbed. ing.

  As shown in FIG. 1, the sensor chip 10 has a rectangular plate shape, and an acceleration detection unit 11 as an acceleration detection element is provided on one surface of the sensor chip 10 (upward surface in FIG. 2). Is provided.

  Although not specifically shown, the acceleration detection unit 11 is configured to include a comb-like movable electrode generally known as an acceleration detection element and a fixed electrode opposed to the comb-like movable electrode.

  And the said movable electrode is displaced to the said detection direction with the application of the acceleration along the detection direction in FIG. Along with this displacement, a capacitance change with the fixed electrode facing the movable electrode occurs, and the applied acceleration is detected by detecting a signal of this capacitance change.

  A plurality of pads 12 are provided on one surface of the sensor chip 10. These pads 12 are provided to take out signals output from the acceleration detector 11.

  The circuit chip 20 has a rectangular plate shape that is slightly larger than the sensor chip 10. A pad 22 is provided around a portion where the sensor chip 10 is mounted on one surface of the circuit chip 20 (upper surface in FIG. 2).

  The circuit chip 20 is configured as a signal processing chip having functions such as sending an input signal to the sensor chip 10, processing an electrical signal output from the sensor chip and outputting it to the outside.

  Such a circuit chip 20 is constituted by, for example, an IC chip in which a MOS transistor, a bipolar transistor, or the like is formed on a silicon substrate using a known semiconductor process.

  The pads 12 of the sensor chip 10 and the pads 22 of the circuit chip 20 are connected by the bonding wires 40. Thereby, both the chips 10 and 20 are electrically connected. The bonding wire 40 is made of gold or aluminum, and is formed by a normal wire bonding method.

  In the present embodiment, the plurality of bonding wires 40 that connect between the pads 12 of the sensor chip 10 and the pads 22 of the circuit chip 20 are fixed by the insulating member 50, and the intervals between the plurality of bonding wires 40 are constant. Is retained.

  Specifically, a plurality of bonding wires 40 that connect between the pads 12 of the sensor chip 10 and the pads 22 of the circuit chip 20 are fixed by the insulating member 50 at the peripheral portion on the sensor chip 10. .

  As the insulating member 50, a resin insulating adhesive, foamed urethane, insulating tape, or the like can be used.

  The ceramic package 30 includes an opening 31 that houses the sensor chip 10 and the circuit chip 20, and a lid 32 that covers the opening 31. The ceramic package 30 is configured, for example, as a laminated body in which a plurality of ceramic layers such as alumina are laminated, and wiring is formed on the surface of each ceramic layer and through holes formed in each ceramic layer. It is.

  Further, a pad 34 is formed in the ceramic package 30, and the pad 34 and the pad 22 of the circuit chip 20 are electrically connected by a bonding wire 40. The pad 34 is electrically connected to a sensor terminal (not shown). In this way, the acceleration detection unit 11 of the sensor chip 10 is electrically connected to the sensor terminal from the pad 12 of the sensor chip 10 via the bonding wire 40, the circuit chip 20, the bonding wire 40, and the pad 34 of the ceramic package 30. .

  FIG. 3 shows an equivalent circuit of the sensor chip 10. As shown in the drawing, the sensor chip 10 includes a first capacitor (referred to as CS1) configured by a first fixed electrode and a movable electrode, and a second capacitor configured by a second fixed electrode and the movable electrode. It is expressed as a circuit provided with (CS2). When the acceleration is received, the entire movable portion is displaced by a spring function of a beam portion (not shown), and the capacitors CS1 and CS2 change according to the displacement of the movable electrode.

  CP1 and CP2 represent parasitic capacitances between the bonding wires 40 that connect the sensor chip 10 and the circuit chip 20. Specifically, CP1 represents a parasitic capacitance generated between both ends of the first capacitor CS1, and CP2 represents a parasitic capacitance generated between both ends of the second capacitor CS2.

  When the bonding wire 40 connected between the pad 12 of the sensor chip 10 and the pad 22 of the circuit chip 20 is deformed due to an impact applied to the sensor device from the outside, and the like, the parasitic capacitance is changed. CP1 and CP2 change, and the sensor output characteristics fluctuate.

  In the present embodiment, the bonding wires 40 are arranged so that the distance between the bonding wires 40 connecting the pads 12 of the sensor chip 10 and the pads 22 of the circuit chip 20 does not change due to an impact applied to the sensor device from the outside. It is fixed with an insulating member 50.

[Manufacturing method]
First, the ceramic package 30 is prepared, and the circuit chip 20 is bonded and fixed to the opening 31 of the ceramic package 30 with an adhesive (not shown) such as epoxy resin or silicon resin. After the adhesive is cured and the circuit chip 20 is bonded and fixed, the sensor chip 10 is bonded and fixed onto the circuit chip 20 via the adhesive film 60.

  Next, the bonding wires 40 electrically connect the pads 34 of the ceramic package 30 and the pads 22 of the circuit chip 20 and the pads 22 of the circuit chip 20 and the pads 12 of the sensor chip 10.

  Next, the insulating member 50 is fixed so that the distance between the bonding wires 40 connecting the pads 22 of the circuit chip 20 and the pads 12 of the sensor chip 10 is kept constant.

  After the bonding wire 40 is fixed by the insulating member 50, the opening 31 of the ceramic package 30 is sealed with the lid 32, and the acceleration sensor device 100 is completed.

[Effects]
According to the configuration described above, even if an impact is applied from the outside, the plurality of wires connected to the sensing unit are fixed by the insulating member, and the distance between the plurality of wires is kept constant. Can be improved.

  Moreover, as an insulating member, it can comprise with resin-made adhesive agents, foaming urethane, or a tape member.

  The plurality of wires can be fixed by an insulating member on the chip of the sensing unit.

  In addition, the sensing unit can be stacked on the circuit chip, a plurality of wires are connected to the circuit chip, and the insulating member can fix the plurality of wires on the circuit chip.

  Moreover, in order to improve the impact resistance, for example, if the entire acceleration sensor device including the sensing unit and the circuit chip is sealed with a resin mold, the impact resistance can be improved. Then, stress is applied to the sensing part due to the thermal expansion of the resin mold and the characteristics of the sensor output change, but since the film member is provided between the sensing part and the circuit chip, the film member The stress caused by thermal strain is absorbed, and the sensor output characteristic change due to temperature change can be suppressed.

  In addition, this invention is not limited to the said embodiment, Based on the meaning of this invention, it can implement with a various form.

  For example, in the above embodiment, the configuration example in which the sensor chip 10 is stacked on the circuit chip 20 has been described. However, the sensor chip 10 and the circuit chip 20 may be arranged side by side in the opening 31 of the ceramic package 30.

  Further, in the above embodiment, the plurality of bonding wires 40 that connect between the pads 12 of the sensor chip 10 and the pads 22 of the circuit chip 20 are fixed by the insulating member 50 at the peripheral portion on the sensor chip 10. For example, a configuration in which a plurality of bonding wires 40 that connect between the pads 12 of the sensor chip 10 and the pads 22 of the circuit chip 20 are fixed by the insulating member 50 on the circuit chip 20 is shown. It is good.

It is a figure showing a schematic top view of an acceleration sensor device concerning one embodiment of the present invention. 1 is a diagram illustrating a schematic cross-sectional configuration of an acceleration sensor device according to an embodiment of the present invention. It is a figure which shows the equivalent circuit of a sensor chip. It is a figure which shows the general schematic cross-sectional structure of the conventional sensor apparatus with which the sensor chip and the circuit chip were laminated | stacked.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Sensor chip, 11 ... Acceleration detection part, 12, 22, 34 ... Pad,
20 ... circuit chip, 30 ... ceramic package, 32 ... lid,
40 ... bonding wire, 60 ... adhesive film, 100 ... acceleration sensor device.

Claims (7)

An acceleration sensor device comprising: a sensing unit (10) that outputs an electrical signal corresponding to an applied acceleration; and a plurality of wires (40) that are electrically connected to the sensing unit and extract the electrical signal. There,
The plurality of wires are fixed by an insulating member (50), and an interval between the plurality of wires is kept constant. The acceleration sensor device according to claim 1, wherein the insulating member is a resin adhesive. The acceleration sensor device according to claim 1, wherein the insulating member (50) is foamed urethane. The acceleration sensor device according to claim 1, wherein the insulating member is a tape member. The sensing part is in a chip shape, and the plurality of wires (40) are connected on the chip,
The acceleration sensor device according to any one of claims 1 to 4, wherein the plurality of wires are fixed on the chip by the insulating member (50). A circuit chip (20) for processing an electrical signal from the sensing unit (10);
The sensing unit (10) is stacked on the circuit chip (20), the plurality of wires (40) are connected to the circuit chip, and the plurality of wires are connected to the insulating member (on the circuit chip). 50. The acceleration sensor device according to any one of claims 1 to 4, wherein the acceleration sensor device is fixed by 50). The film member (60) for absorbing stress generated by thermal strain of the circuit chip (20) is provided between the sensing unit (10) and the circuit chip (20). Or the acceleration sensor device according to any one of items 4 to 4;

Images