JPH04169857A - Semiconductor acceleration sensor - Google Patents

Abstract

PURPOSE:To achieve a higher sensitivity of a sensor without growing size of the apparatus by providing a beam between a top of a pile of a polygonal semiconductor plate and an opposed part of a support frame. CONSTITUTION:For example, an interval between a top part of a rectangular pile 2 and an opposed part (corner part) of a support frame 1 is made larger about 2<1/2>=about 1.4 times than an interval (g) between a center of a side of a rectangle and an opposed part of the support frame 1. Therefore, when a beam 3 is provided between a top of the rectangle of the pile 2 and the op posed part of the support frame 1, the rigidity of the beam 3 becomes so weaker to increase a deflection when acceleration is applied, which allows the enhancing of the sensitivity of a sensor without increase in the support frame 1. The shape of the pile 2 may be polygon other than the rectangle. Here, as the shape of semiconductor chips cut out of a semiconductor substrate is rectangle in general, the rectangle is desirable in view of efficiency of utilizing the surfaces of chips.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultra-small 71TI thorn sensor made of a semiconductor.

[Conventional technology]

In recent years, ultra-compact semiconductor acceleration sensors have been put into practical use that are formed into an integral structure from a semiconductor substrate using etching technology, diffusion technology, or the like. This semiconductor acceleration sensor has 11
It can be formed into an ultra-small size of about 11×1111×0.3111, and can also be formed on the same substrate as the circuit in an integrated circuit.

It is used to detect abnormal vibrations in machine tools, robots, etc., and for motion control such as brakes, suspension, and ventilation in aircraft, rockets, elevators, etc.

3 is a plan view showing an example of a conventional semiconductor acceleration sensor, and FIG. 4 is a sectional view taken along line B-H in FIG. 3. For example, a space g around a rectangular l-2 made of a semiconductor board.
A support frame l made of a semiconductor board is provided across from the support frame l. The support frame 1 and the support frame 2 are connected by a beam 3b made of a semiconductor plate and provided between the center of one side of the rectangle of the support frame 2 and the support frame portion facing the center. Vermilion 3
b is a semiconductor strain gauge 5 for measuring the deflection of this beam.
is provided.

Weight 2. Support frame 1. The beam 3b is usually formed as a monolithic structure from a semiconductor substrate by etching techniques, and the semiconductor strain 5 is formed on the instep of the beam 3b by diffusion techniques.

1.2. Support frame 1. When the acceleration of the semiconductor acceleration sensor consisting of the beam 3b changes, the beam 3b deflects, and the acceleration is detected by measuring the deflection of the beam 3b with a semiconductor strain gauge 5 provided on the beam.

Note that 6 is an extraction electrode of the semiconductor strain gauge 5.

FIG. 5 is an example of a circuit diagram showing details of the semiconductor strain gauge 5, which includes four resistors 10a and 10b.

10c, lod is connected to the bridge, and P is connected between the -10,000 terminals.
When voltage ■ is marked on -Q, between the other terminals R-8,
A signal voltage E is generated according to a change in the resistance value of the resistor described above. These four resistors are provided on the beam 3b,
When the beam 3b bends, the resistance values of these resistors change, so the deflection of the beam 3b (D) can be measured.

FIG. 6 is a plan view showing a different example of a conventional semiconductor acceleration sensor, and FIG. 7 is an lfr plane view taken along the line CC in FIG.

In the semiconductor acceleration sensor 2 of the Polo 1 example shown in FIGS. 3 and 4 above, in order to increase the sensor sensitivity, the beam 3 is
Reduce the width 2 and thickness of b to weaken its rigidity 7X
Although the deflection is increased when the speed is close to that of the cutting edge, there is a certain limit to reducing the width and thickness because the mechanical strength of the beam decreases. In the second example shown in FIGS. 6-2 and 7-7, notches 4a are formed in the fixed frame 1 along both sides of the beam 3a, thereby increasing the length of the beam 3a. Increasing the length of the beam 3a ζ thus weakens its rigidity, increases the deflection of the beam 3a, and increases sensor sensitivity.

[Problem to be solved by the invention]

In the semiconductor acceleration sensor 2 in the second example described above, fixed frames C are installed along both sides of the beam in order to increase sensor sensitivity.
A notch is provided, which increases the length of the beam, but in this case, the fixed frame needs to be made larger by the amount of the notch.

The device has become larger and now ultra-compact! # Signs are damaged.

An object of the present invention is to solve the above-mentioned problems and provide a semiconductor acceleration sensor with increased sensor sensitivity without increasing the size of the device.

[Means to solve the problem]

In order to solve the above-mentioned problems, m1i! of the present invention. In the summer sensor weight, a weight made of semiconductor, a support frame made of semiconductor provided at a predetermined distance around the weight, and a support frame made of semiconductor are connected to each other, and the acceleration is adjusted when the blade is sharpened. In a semiconductor light sensor consisting of a semiconductor beam provided with a semiconductor strain gauge for measuring the deflection of the semiconductor beam, I! The +J weight is made of a polygonal semiconductor board, and the beam is provided between the apex of this polygon and the opposing support frame part.

[Effect]

The distance between the polygonal frame and the support frame provided at a constant interval around the weight is less than the distance between the center of the side of the polygon and the opposing support frame part. , the distance between the apex of the polygon of the weight and the opposing support frame is long. Compared to the conventional acceleration sensor in which a beam is provided between the central part of the east side of the polygon and the opposing support frame part, the present invention provides a beam from the vertex of one polygon to the opposing support frame part. In the acceleration sensor, the length of the beam is long and the deflection when acceleration is applied is large, and the sensor sensitivity can be increased without increasing the size of the support frame.

[Embodiment] FIG. 1 is a plan view showing an embodiment of the semiconductor acceleration sensor of the present invention, and FIG. 2 is a perspective view of a cross section taken along line AA in FIG. 1. The semiconductor acceleration sensor of the present invention differs from the conventional 7X speed sensor shown in FIGS. 3 and 4 in the mounting position of the beam 3. That is, in the conventional semiconductor acceleration sensor, the beam 3b was provided between the center of the side of the square 2 and the opposing support frame 1, but in the semiconductor acceleration sensor of the present invention, the beam 3b is A beam 3 is provided between the apex of the rectangle and the opposing support frame 1 portion.

The distance between the rectangular weight 2 and the support frame 1 provided around the weight at a constant interval g is greater than the distance between the center of the rectangular side of the weight and the opposing support frame. Also, the distance between the apex of the 1L rectangle and the opposing support frame portion is approximately 1.4 times longer. Therefore.

As aforementioned. In the 710 speed sensor of the present invention, in which a beam is provided between the apex of the rectangular shape and the opposing support frame portion, the rigidity of the beam is correspondingly weakened, and the deflection increases when the 7JO movement changes. . Therefore, sensor sensitivity can be increased without increasing the size of the support frame. In addition, the first
In the embodiments shown in FIGS. 2 and 2, the weight is described as being square, but as is clear from the principle, the same applies to polygonal weights. However, a semiconductor chip cut out from a semiconductor substrate is generally square, and the 7JO quick-seal sensor of the present invention, which is formed by etching technology, diffusion technology, etc., has the same external shape as the semiconductor chip. In other words, it is preferable to use one of the rectangular shapes as this is the most efficient way to utilize the surface of the semiconductor chip.

〔Effect of the invention〕

By providing a beam between the apex of the polygonal weight and the opposing support frame, it is possible to replace the conventional acceleration sensor in which a beam is provided between the center of one side of the polygon and the opposing support frame. In comparison, the length of the beam can be increased without increasing the size of the support frame, and sensor sensitivity can be increased. In particular, if the beam has the same square shape as the semiconductor chip, the semiconductor chip surface will be used efficiently, and the beam length will be approximately 1.4
The sensor sensitivity increases accordingly.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the semiconductor chip sensor of the present invention, FIG. 2 is a perspective view of a cross section taken along line A-A in FIG. 1, and FIG. 3 is an example of a conventional semiconductor 710 speed sensor. 4 is a sectional view taken along line B-B in FIG. 3, FIG. 5 is a circuit diagram showing details of the semiconductor strain gauge, and FIG.
FIG. 7 is a plan view showing different examples of conventional semiconductor acceleration sensors. FIG. 7 is a sectional view taken along line CC in FIG. 1...Support frame, 2...Summer, 3...Beam, 5...
Semiconductor switch I 14-Figure C5

Claims (1)

[Claims] 1) A weight made of a semiconductor, a support frame made of a semiconductor provided around the weight at a predetermined interval, and when these weights and the support frame are coupled and acceleration is applied. In a semiconductor acceleration sensor, the weight is made of a polygonal semiconductor plate, and the beam is a support facing the apex of the polygon of the weight. A semiconductor acceleration sensor characterized in that it is provided between a frame portion and a frame portion. 2) In the semiconductor acceleration sensor according to claim 1),
A semiconductor acceleration sensor characterized in that the weight is made of a rectangular semiconductor plate.