JP5507354B2 - Piezoresistive element built-in sensor chip manufacturing method and sensor chip - Google Patents

Description

  The present invention relates to a method of manufacturing a sensor chip with a built-in piezoresistive element and a sensor chip thereof, and more particularly to a method of manufacturing a sensor chip that is reduced in size and thickness.

  Conventionally, various force / moment sensors using piezoresistive elements formed on a semiconductor substrate have been manufactured. As this type of sensor, for example, a force sensor disclosed in Patent Document 1 shown in FIG. Proposed.

  In the sensor of FIG. 3, a force sensor chip 53 incorporating a strain resistance element is mounted on a chip base 52 on the fixing unit 51, and a transmission unit is mounted on the action part of the force sensor chip 53. An input unit 55 is arranged via 54. Also, a damping mechanism portion (buffer device) composed of four columns formed of a solid material (metal, plastic, ceramics, glass, etc.) at the four corners between the flat plate portion of the fixed portion 51 and the flat plate portion of the input portion 55. ) 56 is provided.

  According to such a sensor, the external force applied to the input unit 55 is absorbed by, for example, 90% by the damping mechanism unit 56 and is weakened. When% is applied, force / moment can be detected.

JP 2008-292510 A

  However, in the conventional force / moment sensor structure as shown in FIG. 3, the chip base 52, the force sensor chip 53, the transmission unit 54, the input unit 55, and the damping mechanism unit 56 are assembled to the fixed unit 51. In addition, there is a problem that high accuracy is required to some extent in the dimension and assembly of each part, and it is not possible to manufacture easily and at low cost.

  In addition, the damping mechanism portion 56 that absorbs external force is composed of four pillars or the like (in other examples of Patent Document 1, it is composed of a disk), and the members of the damping mechanism portion 56 are assembled. However, it was not possible to promote downsizing and thinning.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a sensor chip with a built-in piezoresistive element that can be manufactured easily and at low cost, and that can promote downsizing and thinning. And providing a sensor chip thereof.

In order to achieve the above object, a method of manufacturing a sensor chip with a built-in piezoresistive element according to the first aspect of the present invention includes mounting an IC for measurement processing on each of a plurality of recesses on a collective substrate , and this IC. sensor unit piezoresistive elements are formed on the top of the steps to connect the (pressure sensing section) by wire bonding, for each of said plurality of sensor units, transmission for producing stress on the piezoresistor A step of attaching a body (pressurizing body) and an external force receiving plate having a larger area than the upper surface of the transmission body, and between the external force receiving plate including the wire bonding region of the sensor unit and the sensor unit and the collective substrate, And a resin filling step of filling a resin for fixing / buffering, wherein a plurality of sensor chips are manufactured by dividing the aggregate substrate body obtained through the above steps into individual pieces.
According to a second aspect of the present invention, there is provided a sensor chip with a built-in piezoresistive element, wherein a measurement processing IC mounted in a recess on the substrate is connected to the substrate by wire bonding above the measurement processing IC. The formed sensor part, a piezoresistive element of the sensor part, a transmitter that generates stress on the piezoresistive element, and a plate-like body that is attached to the transmitter and has a larger area than its upper surface becomes, and the external force receiving plate for applying an external force from the transmission body into the piezoresistive element, which is filled between the force-receiving plate and the sensor unit及beauty board including a wire bonding region of the sensor unit fixed / Buffering resin.

  According to the first aspect of the present invention, a cylindrical or polygonal column-shaped transmission body is disposed on the piezoresistive element of the sensor unit connected to the collective substrate, and at the same time, a flat plate-like external force receiving plate is placed on the transmission body. In addition, a fixed / buffer resin is filled between the external force receiving plate, the sensor unit, and the collective substrate by a potting method to form a collective substrate, and the collective substrate is separated into pieces by dicing or the like. Thus, a sensor chip with a built-in piezoresistive element is manufactured.

  According to the method for manufacturing a sensor chip with a built-in piezoresistive element of the present invention, it is not necessary to assemble many parts, and since high accuracy is not required in the dimensions and assembly of each part, easy and low cost manufacturing is realized. In addition, there is an effect that it is possible to promote downsizing and thinning of the sensor chip.

It is sectional drawing which shows the manufacturing process of the sensor chip with a built-in piezoresistive element based on the Example of this invention. It is sectional drawing which shows the structure of the sensor chip with a built-in piezoresistive element separated. It is a perspective view which shows the structure of the conventional force and moment sensor.

  FIG. 1 shows a manufacturing process (method) of a sensor chip with a built-in piezoresistive element according to an embodiment of the present invention. In this embodiment, the IC 2 is first connected in FIG. (IC connection process). That is, the interposer 1 is formed as a collective substrate (having wiring and the like) for manufacturing a plurality of sensor chips, and an IC 2 that performs processing related to measurement of force and moment is provided in the concave portion of the interposer 1 with bumps, gold, and the like. The wires 3 are connected and mounted by wire bonding.

  Next, in FIG. 1 (B), a sensor part (pressure-sensitive part) 4 is placed so as to close the upper part of each IC 2, and the sensor part 4 is a gold wire as shown in FIG. 1 (C). 3 is connected to the interposer 1 by wire bonding (or combined use of bumps or the like) (sensor part connecting step). A plurality of piezoresistive elements (parts) are arranged, for example, in a predetermined arrangement at the approximate center of the upper surface of the sensor unit 4 so that a plurality of axes (for example, three axes) force and the like are detected by the plurality of piezoresistive elements. Composed.

  In FIG. 1 (D), a cylindrical or polygonal column-shaped transmission body (pressurizing body) 5 is attached and arranged to the piezoresistive element on the upper surface of the sensor unit 4 by an adhesive, and on the upper surface of the transmission body 5. The flat external force receiving plate 6 is attached and disposed by an adhesive (transmitter and external force receiving plate attaching step). The transmission body 5 serves to transmit the external force received by the external force receiving plate 6 to the sensor unit 4, and is arranged at a position where a plurality of piezoresistive elements can generate compression and tensile stress and maintain sensitivity. . The thickness of the transmission body 5 may be set so that the external force receiving plate 6 does not contact the gold wire 3, and the size (size) of the external force receiving surface (upper surface) of the external force receiving plate 6. , It is possible to change the force applied to the transmission body 5 by the moment.

  Note that the transmission body 5 and the external force receiving plate 6 may be made of different materials or the same material, and the transmission body 5 and the external force receiving plate 6 are integrally formed. May be attached to the upper surface of the sensor unit 4.

  In FIG. 1E, a fixing / buffering resin 7 made of an elastic material such as silicone is injected and filled between the external force receiving plate 6 and the sensor unit 4 and the collective substrate 1 by a potting method (resin Filling step). The fixing / buffering resin 7 serves to fix the external force receiving plate 6 to the sensor unit 4 and the collective substrate 1 and to integrate the sensor chip, and to receive the external force received by the external force receiving plate 6 by its elastic force. It will serve as a buffer that absorbs and weakens (fixing function and buffering function). In addition, since the degree of buffering (rate of external force absorption) varies depending on the material of the fixing / buffering resin 7, the material is determined in consideration of the degree of buffering.

  The thickness of the external force receiving plate 6 needs to be reduced in order to reduce the thickness of the sensor chip. However, since the strength decreases if the thickness is reduced, it is preferable to use a material having high rigidity for the external force receiving plate 6. . However, since the fixing / buffering resin 7 is used in the present invention, a resin having a low rigidity, such as a resin, can be used as the material of the external force receiving plate 6.

  Finally, in FIG. 1 (F), the aggregate substrate body 8 manufactured in FIG. 1 (E) is separated into pieces by cutting with a blade, and a large number of sensor chips 10 with built-in piezoresistive elements are manufactured.

  FIG. 2 shows the configuration of one finally obtained sensor chip 10. In the sensor chip 10 according to the embodiment, the external force receiving plate 6, the sensor unit 4, and the collective substrate 1 are fixed. / The buffer resin 7 is filled. As described above, the fixing / buffering resin 7 performs a buffering function. As the buffering function, the function of absorbing and weakening the force to be measured applied to the external force receiving plate 6 and the external force receiving plate 6 alone are used. However, when an excessive force or momentary impact is applied to the entire sensor chip 10, there is a function of absorbing the excessive force or impact and preventing the sensor chip 10 from being broken.

  In the function of absorbing the force to be measured, the external force can be dispersed and the range of detectable force can be changed by changing the elastic modulus of the fixing / buffering resin 7. When detecting, a resin material having a low elastic modulus is used, and when detecting a large force, a resin material having a high elastic modulus is used.

  In the sensor chip 10 of the embodiment, the sensor unit 4 having the IC 2 and the piezoresistive element is provided on the interposer (substrate) 1. The IC 2 is arranged by forming a recess in the interposer 1. By disposing the sensor unit 4 above the IC 2 so as to straddle, the area of the sensor chip 10 is reduced. That is, instead of arranging the IC 2 and the sensor unit 4 side by side on the same plane and arranging them horizontally, the sensor chip 10 can be reduced in size and reduced in size by arranging them both in the vertical direction. By using the recess of the interposer 1, the thickness can be reduced.

  Further, by reducing the thickness of the transmission body 5 and the external force receiving plate 6 as much as possible and fixing the external force receiving plate 6 with the sensor unit 4 and the interposer 1 using the fixing / buffering resin 7, the sensor chip 10. There is an advantage that the thickness can be reduced. That is, in order to ensure a predetermined strength in the sensor chip 10, the external force receiving plate 6 needs a certain thickness, but in the present invention, the fixing / buffering resin 7 serves to strengthen the strength. The overall thickness of the sensor chip can be reduced by thinning the external force receiving plate 6.

  The present invention can be applied to a sensor chip incorporating a piezoresistive element, for example, various sensors that detect force, moment, acceleration, and the like.

1 ... interposer (collective substrate), 2 ... IC (integrated circuit),
4 ... Sensor part (built-in piezoresistive element), 5 ... Transmitter,
6 ... external force receiving plate, 7 ... fixing / buffer resin,
8 ... Collective substrate body, 10 ... Sensor chip.

Claims (2)

A step for each of the plurality of recesses on the aggregate substrate, an IC for measurement processing, and connect the sensor unit to piezoresistive elements are formed on an upper portion of the IC by wire bonding,
For each of the plurality of sensor units, a step of attaching a transmission body for generating stress in the piezoresistive element and an external force receiving plate having a larger area than the upper surface of the transmission body;
A resin filling step of filling a fixing / buffering resin between the external force receiving plate including the wire bonding region of the sensor unit and the sensor unit and the collective substrate;
A method for manufacturing a sensor chip with a built-in piezoresistive element, wherein a plurality of sensor chips are manufactured by dividing the aggregate substrate body obtained through the above-described steps. A measurement processing IC mounted in a recess on the substrate;
A sensor unit connected to the substrate by wire bonding at the upper part of the measurement processing IC and having a piezoresistive element formed thereon;
A transmitter that is arranged with respect to the piezoresistive element of the sensor unit and generates stress in the piezoresistive element;
An external force receiving plate for attaching an external force to the piezoresistive element from the transmission body, comprising a plate-like body attached to the transmission body and having an area larger than its upper surface;
The external force receiving plate and the fixed / buffering resin filled between the sensor unit及beauty board, piezoresistive element built-in sensor chip comprising a comprising a wire bonding region of the sensor unit.

Images