JPH05322919A - Structure of multidimensional semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To align the position of a sensor chip to a stem simply and to reduce the cost of a sensor. CONSTITUTION:As a bonding head for bonding a sensor chip 48, a stem 50, whose material is cobalt alloy and the like having the thermal expansion coefficient close to those of a glass stage 24, a semiconductor pellet 20 and the like, and which contains hermetic seals 52 for lead pins 51 formed of glass, is provided. A recess part 54 having the shape for controlling the operating range of a weight 16 of a sensor is formed in the stem 50. A size (a) of the sensor chip 48 facing the recess part 54 is smaller than a size (b) of the opening part of the recess part 54 and larger than a size (c) of the bottom part of the recess part 54. The sensor chip 48 is die-bonded so that the chip enters into the recess part 54. Thus, the position alignment of the sensor chip 48 with the stem 50 can be achieved simply, and the cost can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a large number of strain-sensitive resistance bridges utilizing the piezoresistive effect, a diaphragm type flexible portion, and a weight joined to an acting portion connected to the flexible portion. And a structure of a multi-dimensional semiconductor acceleration sensor having the same.

[0002]

2. Description of the Related Art A large number of strain-sensitive resistance bridges (strain-sensitive gauges) 10 utilizing a piezoresistive effect, a diaphragm type flexible portion 12, and a flexible portion 12 as shown in FIG. A multi-dimensional semiconductor acceleration sensor having a weight body 16 joined to the acting portion 14 connected to the has been developed.

5A is a sectional view taken along the Z-axis of the sensor, and FIG. 5B is a top view of the XY plane of the sensor. In addition, generally, the strain-sensitive resistance bridge 10
Is formed on the surface of the sensor chip 18 by thermal diffusion or the like, and is provided on the flexible portion 12. Reference numeral 20 in FIG.
Is a semiconductor pellet including the flexible portion 12, the acting portion 14, and the fixing portion 22, 23 is a member for controlling the operating range of the weight body 16, 24 is a pedestal made of glass, 26 is a bonding pad, and 28 is a bonding pad. A wire, 30 is a package, 32 is a cap, and 34 is a lead.

The principle of detection of such a multi-dimensional semiconductor acceleration sensor is that, when acceleration is applied to the weight body 16, the flexible portion 12 is distorted by the force, and the distortion is sensed using the strain sensing resistance bridge 10. Is to be converted to.

Further, Japanese Patent Laid-Open No. 3-2535 has been proposed as a method of manufacturing a multidimensional semiconductor acceleration sensor having such a structure. In the method of this publication, as shown in FIG. 6, a groove 38 is formed in a chip unit by a anodic bonding method or the like on a sensor substrate 36 in a wafer state before cutting and separating (FIG. 6A). It is shown that the glass body 40 and the pedestal 24 are manufactured at one time by joining the glass plates 40 (FIG. 2B) and then dicing the glass plate 40 (FIG. 2C). Has been done.

In this manufacturing method, since the lower surface positions of the weight body 16 and the pedestal 24 are at the same height, the weight body 1 would not be assembled as it is in a normal bonding head or the like.
6 does not operate as a sensor because the degree of freedom of operation is lost. Therefore, as shown in FIG. 7, a control board (support base) 44 having a recess 42 for appropriately controlling the movable range of the weight body 16 is adhered to the weight body 16 and the lower surface of the pedestal 24, After that, the wafer of the sensor substrate 36 together with the control substrate 44 and the pedestal 24 is cut into the semiconductor pellets 20 to form sensor elements.

[0007]

In the actual manufacture of the conventional multi-dimensional semiconductor acceleration sensor, the control substrate 44 is collectively attached to the glass pedestal by using the anodic bonding method, so that the photolithography is performed on the silicon single crystal substrate. An etching processed by the lithographic method is used.

However, since the weight body 16 of the chip has a small shape of, for example, about 2 mm × 2 mm, the dimensional accuracy of the recessed portion 42 of the control substrate (supporting base) adhered to the lower portion of the chip is at least 0. It needs to be as high as about 0.05 mm. Therefore, in this type of multi-dimensional semiconductor acceleration sensor, there is a problem in that the accuracy of the alignment becomes a problem at the time of manufacturing, and the alignment becomes difficult, which causes a decrease in yield during mass production.

Further, the silicon single crystal substrate is expensive,
Further, it takes a lot of man-hours to perform the etching process of the substrate by the photolithography method, which is a factor of the high cost of this kind of multidimensional semiconductor sensor device, and there has been a demand for cost reduction of the device.

The present invention has been made to solve the above-mentioned conventional problems, and it is an object of the present invention to provide a structure of a multidimensional semiconductor sensor which can be easily aligned and can reduce the cost. To do.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a large number of strain sensitive resistance bridges utilizing a piezoresistive effect, a diaphragm type flexible portion, and a weight connected to an acting portion connected to the flexible portion. In a structure of a multi-dimensional semiconductor acceleration sensor having a body, a stem having a hermetic seal of a lead pin as a bonding head for bonding a sensor chip is made of a material such as Kovar alloy having a thermal expansion coefficient close to that of a pedestal or a semiconductor substrate. The stem is provided with a recess having a shape for controlling the operating range of the weight of the sensor, and the size of the side of the sensor chip facing the recess is smaller than the size of the recess opening. small,
The size of the bottom of the recess is larger than the size of the bottom of the recess, and the sensor chip is die-bonded so as to enter the recess.

Further, in the present invention, the sensor chip may be provided with a taper portion on the end surface of the chip pedestal.

[0013]

In the present invention, the stem is provided as the bonding head for bonding the sensor chip, and the stem is provided with the recessed portion. Since the structure is sufficient if the sensor chip is inserted into this recessed portion, The control board (support base) provided for the sensor is not required, and the cost can be reduced. Further, the step of bonding the control substrate to the sensor wafer (for example, the anodic bonding method) is unnecessary, and the cost can be reduced. Further, the size of the side of the sensor chip facing the recess is smaller than the size of the recess opening, and is larger than the size of the bottom of the recess, so when the sensor chip is die-bonded to the stem, Since the edge of the opening of the recessed portion of the stem can be used as the alignment mark, the alignment can be performed easily and the yield in mass production can be improved.

In the present invention, if a taper portion is further provided on the end surface of the chip pedestal of the sensor chip, the recess has a large opening and a small bottom, so that the sensor chip can be stably die-bonded to the stem. You can As a result, the alignment can be further simplified and the yield in mass production can be improved.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, FIG. 1 shows a first embodiment of the multidimensional semiconductor acceleration sensor of the present invention. As shown in FIG. 1, the sensor according to the first embodiment includes a large number of strain-sensitive resistance bridges 10 utilizing a piezoresistive effect, a diaphragm-type flexible portion 12, and
The sensor chip 48 has a weight body 16 joined to the acting portion 14 connected to the flexible portion 12, and the same parts as those of the sensor shown in FIG. I will omit it.

The sensor of the first embodiment is a sensor chip 48.
Stem 5 as a bonding head for bonding
Has 0. The stem 50 is a base 2 made of glass.
4 or a silicon substrate (semiconductor pellet 20) or the like, which is a so-called hermetic stem made of a Kovar alloy or the like having a coefficient of thermal expansion close to that of the silicon substrate and having a hermetic seal 52 of the lead pin 51 made of glass. Also,
The stem 50 is formed with a recess 54 having a shape for controlling the operating range of the weight body 16 of the sensor. The recess 54 can be manufactured by a precision press or the like.

As shown in FIG. 2, the size a of the sensor chip 48 on the side facing the recess 54 is smaller than the size b of the opening of the recess 54 and the recess 5 is formed.
4 is larger than the size c of the bottom. Further, the sensor chip 48 is installed in the recess 54 of the stem 50,
The sensor is formed by die-bonding. At this time, the sensor chip 48 is aligned so that it fits into the recess 54 of the stem 50, and then die-bonded with an adhesive 55.

Therefore, since the edge of the opening of the recessed portion 54 of the stem 50 can be used as a positioning mark, the positioning can be easily performed and the yield in mass production can be improved.

Next, a second embodiment of the multidimensional semiconductor acceleration sensor of the present invention will be described. The sensor of this second embodiment is
The sensor chip 58 shown in FIG. 3 is provided, and the same parts as those of the first embodiment sensor are designated by the same reference numerals and the description thereof will be omitted.

FIG. 4 shows the structure of the sensor chip 58 before (A) and after (B) assembly. As shown in FIG. 4A, in the sensor chip 58, a taper portion 56B is previously formed on the end surface 56A of the pedestal 56, which is in contact with the recess 54, with a dicing saw or the like.

As described above, in the second embodiment, the tapered portion 56B is provided on the end surface 56A of the pedestal 56 of the sensor chip 58, and the recessed portion 54 has a tapered opening with a large opening and a small bottom. The sensor chip 58 can be die-bonded to the stem 50 more stably than in the first embodiment. Also, the alignment can be simplified,
The yield in mass production can be improved.

In the above embodiments, FIGS. 1 to 4 show structural examples of the multi-dimensional semiconductor acceleration sensor of the present invention, but these are examples, and other configurations are possible within the scope of the present invention. Can also be taken. For example, the stem is not limited to the material made of Kovar alloy, and any other material can be used as long as it has a coefficient of thermal expansion close to that of the pedestal or the semiconductor substrate.

[0023]

As described above, according to the present invention,
The control board (support base) of the multi-dimensional semiconductor acceleration sensor is not required, and the cost can be reduced. Further, the step of bonding the control substrate to the sensor wafer (for example, the anodic bonding method) is unnecessary, and the cost can be reduced. Further, when the sensor chip is die-bonded to the stem, the edge of the opening of the recessed portion of the stem can be used as a positioning mark, so that the positioning can be easily performed and the yield in mass production can be improved.

Further, in the present invention, if a taper portion is provided on the end surface of the chip pedestal of the sensor chip, since the recess has a large opening and a small bottom, the sensor chip is stably die-bonded to the hermetic stem. be able to. This can further simplify the alignment,
It is possible to obtain an excellent effect that the yield in mass production can be improved.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram of a first embodiment of a multidimensional semiconductor acceleration sensor of the present invention.

FIG. 2 is a peripheral configuration diagram of the sensor chip of the first embodiment.

FIG. 3 is a sectional configuration diagram of a second embodiment of the multidimensional semiconductor acceleration sensor of the present invention.

FIG. 4 is an assembly configuration diagram of the sensor chip of the second embodiment on a stem.

5A and 5B are configuration diagrams of a conventional multidimensional semiconductor acceleration sensor, in which FIG. 5A is a sectional view and FIG. 5B is a top view.

FIG. 6 is an explanatory diagram of a manufacturing process of a conventional multidimensional semiconductor acceleration sensor.

FIG. 7 is a manufacturing process explanatory diagram of a conventional multidimensional semiconductor acceleration sensor.

[Explanation of symbols]

 20 semiconductor pellet 24 pedestal 48 sensor chip 50 stem 51 lead pin 52 hermetic seal 54 recessed portion 55 adhesive 56 pedestal 56A end surface 56B taper portion

Claims (2)

[Claims] 1. A multi-dimensional semiconductor acceleration having a large number of strain-sensitive resistance bridges utilizing a piezoresistive effect, a diaphragm-type flexible portion, and a weight body joined to an action portion connected to the flexible portion. In the structure of the sensor, as a bonding head for bonding the sensor chip, a Kovar alloy or the like having a coefficient of thermal expansion close to that of a pedestal or a semiconductor substrate is used as a material, and a stem having a hermetic seal of a lead pin is provided. A recess having a shape that controls the operating range of the weight body of the sensor is formed, and the size of the side of the sensor chip that faces the recess is smaller than the size of the recess opening, and the bottom of the recess is The multi-dimensional semiconductor acceleration is larger than the size, and the sensor chip is die-bonded so as to fit in the recess. The structure of the capacitor. 2. The structure of a multidimensional semiconductor acceleration sensor according to claim 1, wherein the sensor chip is further provided with a taper portion on an end surface of the chip pedestal.