JPS61208273A - Tactile sensor - Google Patents

Abstract

PURPOSE:To eliminate an accident of which a bonding wire is disconnected even when an object is brought into contact by concentrating load to a sphere fitted at the central section of a beam and making the sphere higher than the surface of a substrate. CONSTITUTION:A sapphire sphere 22 is used, the sapphire sphere 22 is placed on a through-hole 19, and the whole surface is coated with an silicone rubber 23 through a potting method. A pedestal 40 has a recessed section 41, and is pasted so that through-holes 18, 18' for a tactile sensor and beams 20 are positioned. Since the pedestal 40 has a base in the recessed section 41, the central sections of the beams 20 are brought into contact with the bottom of the recessed section 41 and stopped even when a load higher than an allowance is applied to the beams 20, thus preventing the deflection of the beams to a fixed quantity or more, then obviating the breaking of the beams.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a tactile sensor, and particularly to a tactile sensor made of semiconductor.
This invention relates to a tactile sensor used for hands, etc.

[Conventional technology]

In recent years, inexpensive and high-performance microcombinators have become popular.
By using these tools, automation and robotization are progressing in various industrial fields. However, robots currently in practical use can only carry out tasks such as lifting, carrying, processing, and assembling objects of a certain shape, size, or weight based on a certain program. I can't.

On the other hand, due to the diversification of consumer groups, there is a strong tendency towards high-mix, low-volume production.FMS (Flexible Manufacture)
There is a call for the development of an automation technology called "acturing8 system". In this trend of automation, it is necessary to equip robots, robots, or automatic machines with various sensors that replace human sensory organs, and to receive information from sensors for control. Among such sensors, sensors are equipped on the fingers or hands of robots and are used to recognize the shape of an object by directly touching it, or to judge the hardness of the object from the sense of pressure. There is a recognized need for tactile sensors to measure forces on objects during assembly operations.

[Problem that the invention seeks to solve]

There are a variety of tactile sensors that have been reported so far, including those using pressure-sensitive conductive rubber, those using microswitches, and those using carbon fiber (Automatic Technology Vol. 14, No. 6, p. 37 - Pages 42 and 61-70
page). These tactile sensors have drawbacks such as being too large, having poor linearity and repeatability, or being able to detect only on-off information. In addition, when measuring pressure distribution, it is necessary to arrange single pressure sensors in an array, but this is difficult to do for the moving parts of the fingers and hands of computers, robots, and robots, which require an extremely large number of wiring lines for signal processing. If it is hit, it will be less reliable.

Another possible method is to directly or indirectly push the diaphragm part of the semiconductor pressure cassette/stainer using the piezoresistance effect. The method of using a semiconductor pressure sensor is an excellent method because it has excellent sensitivity and linearity, and the signal processing section can be integrated, but it is difficult to control the film thickness of the diaphragm at a constant level. , the variation becomes larger when it is made into a play. On the other hand, if the film thickness is increased to avoid this, there is a drawback that the sensitivity becomes extremely poor.

Also, when implementing a semiconductor tactile sensor,

It is also necessary to draw out the bonding wire to connect the external circuit. In the case of a tactile sensor, since an external object touches the element surface, it is possible that the bonding wire may be cut. Therefore, it is necessary to take measures to prevent such accidents from occurring.

An object of the present invention is to provide a tactile sensor that eliminates the above-mentioned drawbacks.

[Means for solving problems]

The tactile sensor of the present invention includes a beam supported on one side or both ends formed by drilling a through hole in a semiconductor substrate;
A bridge circuit or a half-bridge circuit is constituted by a diffusion layer resistor provided on at least one portion on the beam and close to the support portion of the beam, and the diffusion layer resistor further provided on the support portion of the beam. Drill a hole in a part of the beam with a diffusion layer resistor.

It is composed of a round ball that is placed there.

〔Example〕

Next, embodiments of the present invention will be explained using drawings. Figures 1 (a) to (e) are a plan view and a cross-sectional view for explaining the manufacturing method of the first embodiment of the present invention. FIG. 1(a) is a plan view of the tactile senna in an intermediate process, FIG. 1(b) is a sectional view taken along line AA', and FIG. 1(c) is a sectional view of the tactile senna after beam formation. FIG. 1(d) is a plan view of the tactile sensor after the final step, and FIG. 1(e) is a sectional view taken along line BB'.

First, as shown in FIGS. 1(a) and 1(b), boron is diffused into an n-type silicon substrate 10 with a crystal plane (110), and diffusion layer resistors 11, 12 each having a width of 10 μm and a length of 100 μm are formed.
13 and 14 are formed and serve as resistors for the bridge circuit. Then, the surface is covered with an oxide film 15, and the oxide film 15 is selectively removed to form two spaced parallel windows 16 and 16' and a square window 17 between them. Window 16.16' is 50 wide
0 μm, length 15 mm, window 17 has a side of 350 μm
Dimensions.

Next, as shown in FIG. 1(c), using the oxide film 15 as a mask, the silicon substrate 10 is etched with a hydrazine solution at 90°C.
Through hole 18°is' and 1 that penetrates through to the bottom surface
Open 9.

In this example, since the silicon substrate 10 with the (110) plane orientation is anisotropically etched using hydrazine and hydrazine, the through holes 18 and 18' are formed.

The pattern accuracy of 19 is determined by the mask of oxide film 15, that is, the window 16.
．． Determined with an accuracy of 16', 17, and machined vertically.

Ching is removed. This forms a beam 20 that is supported at both ends.

Next, as shown in FIGS. 1(d) and 1(e)K, an aluminum wiring 21 is formed and the entire surface is covered with a protective oxide film 15'. The aluminum wiring 21 connects four resistors 11 to 14 in series K in a ring shape, and the four resistors form a bridge circuit. The diagonal points of the − group are used as input terminals, and the diagonal points of the other groups are used as output terminals.

Next, the round ball, which is the most important part of the present invention, is inserted into the through hole 1.
Set it at 9. A round sphere with a diameter of 0.5 fi? Using the fire ball 22, insert this sapphire ball 22 into the through hole 19.
Place the silicone rubber on the entire surface using the botting method.
cover with

Figures 2(a) and (b) are similar to Figure 1(a) and (e).
FIG. 2 is a plan view and a sectional view taken along line cc' of a first example of a pedestal on which a tactile sensor shown in FIG.

The pedestal 25 has an opening 26t in the center, and the through hole 18 of the tactile sensor shown in FIGS.
．． A tactile sensor is attached to the surface of the pedestal so that 18' and beam 20 are located.

FIG. 3 is a characteristic diagram showing the relationship between the applied load and the electrical output of the embodiment of Sui-Tei 1.

The horizontal axis represents the load applied to the beam 20, and the vertical axis represents the burr.

shows the output voltage across the terminal. There is a very good linear relationship between the load and the output voltage, and the % reproducibility is also good.

A tactile sensor with a cantilever structure was fabricated using a process similar to that described above, and the same characteristics as shown in FIG. 3 were obtained.

Figure 4 (ra), (b) is similar to Figure 1 (d), (e).
The pedestal 40 has a concave portion 41t, and the concave portion 4 has a recess 41t shown in FIG. 1 (dl, (e)). Through hole 18.1 of the tactile sensor shown in
8' and the beam 20 are attached. Since this pedestal 40 has a bottom surface in the recess 41, even if a load exceeding the allowable value is applied to the beam 20, the center part of the beam 20 will come into contact with the bottom of the recess 41 and stop, so that the beam will not deflect more than a certain amount. This can prevent damage to the beams. 5 is a sectional view of a second embodiment of the present invention.

In this embodiment, the back surface of the beam 20 is slightly etched so that the back surface 52 of the beam 20 is slightly higher than the back surface 51 of the silicon substrate 10. With this shape, a flat plate pedestal can be used, and even if a force exceeding the allowable value is applied, the beam 20 will stop in contact with the flat plate pedestal, so the beam 20 can be prevented from being destroyed. In two embodiments, the beam dimensions fc 500 μm width, 1
．． The length is 5 fl, and on this beam there is a beam with a width of 10 μm and a length of 100 mm.
Although a .mu.m diffusion layer resistor was fabricated, the dimensions are not limited to this. Further, although sapphire balls are used as the protrusions, the material and forming method are not limited thereto either. Nine, the output voltage was extracted by constructing a bridge circuit using four resistors 11 to 14, but a half-bridge circuit consisting of only half of the bridge circuit, and two resistors (
For example, it is also possible to form a half-bridge circuit in which the resistors 11 and 12) are connected in series, and the connection point and the ground power source are output terminals, and both ends are voltage input terminals. Correlation similar to that shown in FIG. 3 can also be obtained in the case of a half-bridge circuit.

[Effect of idea]

As explained in detail above, the present invention is configured so that the load is concentrated on the ball provided at the center of the beam, and the ball is also raised higher than the board surface, so even if an object touches it, the bonding line There is no accident of breakage, the manufacturing process is greatly simplified compared to the conventional one, and a tactile sensor with good precision and less failure can be obtained.

[Brief explanation of drawings]

1(a) to 1(e) are a plan view and a sectional view for explaining the manufacturing method of the first embodiment of the present invention, and FIG. 1(a) is a plan view of the tactile sensor in an intermediate process. Figure 1(b) is a cross-sectional view taken along the line A-A', Figure 1(c) is a cross-sectional view of the tactile senna after forming the beam, and Figure 1(d) is a plan view of the tactile senna after the final process. , FIG. 1(e) is a cross-sectional view taken along line B-8', and FIG. 2(a) and (a) are plan views of the first example of the pedestal on which the tactile sensor shown in FIG. 1(c) and (d) is mounted. 3 is a characteristic diagram showing the relationship between the applied load and the electrical output of the first embodiment, and FIGS. 4(a) and 4(b) are the first embodiment.
A plan view and a sectional view of the second example of the pedestal on which the tactile sensor shown in FIGS. (c) and (d) are mounted, and FIG.
FIG. 10...Silico 7 substrate, 11, 12, 13.1
4... Diffusion layer resistance, 15... Oxide film,
15'...Protective oxide film, 16.16', 17.
...Window, 18.18', 19...Through hole, 21...Aluminum wiring, 22...
・Sapphire ball, 23...Silicone rubber, 25
...Pedestal, 26...Opening hole, 40...
...Pedestal, 41...Recess, 51...
Back side of the board, 52... Back side of the beam. 'T11 diagram Z diagram 0 /,, + W/load (Kl) - 謬3 diagram

Claims (1)

[Claims] a beam supported on one side or both ends formed by drilling a through hole in a semiconductor substrate; a diffusion layer resistor provided on at least one portion of the beam close to the support portion of the beam;
A diffusion layer resistor further provided on the support portion of the beam and forming a bridge circuit or a half bridge circuit with the diffusion layer resistor, and a round ball made in a hole formed in a part of the beam and installed in the hole. A tactile sensor characterized by: