JPH0739976B2 - Tactile sensor manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a tactile sensor, and more specifically, a plurality of sensor cells are arranged in a matrix on a common elastic floor, and a pressure receiving portion is provided for each sensor cell. The present invention relates to a method of manufacturing a tactile sensor which is capable of detecting a force applied via a robot and is suitable for being mounted on a robot hand or the like.

[Prior Art] Conventional robots are often driven by sequence control or open-loop control, and work is performed in a specific limited environment. It was For example, in the case of a pick-and-place robot, parts are mounted in a flow work, and it is limited to a series of specific operations such as gripping a specific part, and the function of selecting and gripping different types of parts is not available. I don't have it. However, recently, as robots have become more intelligent, visual sensors and tactile sensors corresponding to human senses have been developed, and robots capable of operating in various environments are being put to practical use.

A distributed tactile sensor is a sensor for such an intelligent robot. Such a sensor is attached to a robot hand or the like, and when the robot hand grips an object, the signal obtained from the sensor is detected and feedback control is performed to control the gripping force of the object or recognize the hardness. Is something that can be done.

FIG. 9 shows an example of a conventional tactile sensor. In this example, thin conductive rubber strips A and rubber strips B intersecting at right angles to each other are combined in two layers, and the force applied in the direction perpendicular to the rubber strip arrangement surface increases the area of the rubber strip contact portion. , The change in resistance is detected and the magnitude of the applied force is known. However, in such a tactile sensor, an output proportional to the applied force cannot be obtained and the output becomes non-linear, and it has a drawback that it is not suitable for detecting the distribution of force at high density.

In order to solve the above-mentioned drawbacks, tactile sensors as shown in Figs. 10 to 12 have been developed. In FIGS. 10 and 11, 1 is a sensor cell of a detection element, 2 is a sensor cell
The pressure receiving portions 3A to 3D, which are formed on the sensor cell 1 and to which the gripping force is applied as a substantially vertical load, are arranged around the pressure receiving portion 2 on the sensor cell 1, and are semiconductor strains for detecting the strain generated in the sensor cell 1. The gauges 4, 4 are bump electrodes similarly arranged on the sensor cell 1 , and 5 is an elastic floor which holds the sensor cell 1 and acts as an elastic body.

Here, the semiconductor strain gauges 3A to 3D are incorporated in a Wheatstone bridge circuit as shown in FIG. 12, and the resistance change in the semiconductor strain gauges 3A to 3D is added to the sensor cell 1 by taking it out from the diagonal terminals. Force is detected as a strain value, and the output signal from the semiconductor strain gauges 3A to 3D is taken out to the outside through the bump electrode 4 and the flexible wiring board (not shown) by supplying the power source (V) to the bridge circuit. be able to.

[Problems to be Solved by the Invention] By the way, the tactile sensor of the above-mentioned form is composed of an elastic floor, a sensor cell, a pressure receiving portion on the sensor cell and a flexible wiring board (not shown), and a skin covering these, There is a problem in the method of joining the sensor cell and the pressure receiving portion and in the shape.

That is, FIG. 13 shows the operation when such a conventional pressure receiving portion is provided on the sensor cell. The sensor cell 1 is placed on the heated heater 6 and the pressure receiving portion 2 is held by the tweezers 7. Then, the flux 8 is applied to the lower surface thereof, and the solder pellets 9 are further attached via the flux 8.
While keeping the shape as shown in the figure, it is lowered in the direction of the arrow and manually placed one by one on the vapor deposition film 10 made of copper or the like formed on the upper surface of the sensor cell 1 , and the solder pellets 9 are heated by the heater 6. It was made to melt and join by.

However, when joined in this manner, Sensase <br/> only or workability such as perpendicularity becomes uneven with respect to the positional accuracy or the sensor cell 1 of the plane of the pressure receiving portion 2 with respect to the center of Le 1 or worse, high manufacturing cost Tsuku.

Further, as shown in FIG. 14, since the corner portion 11 is formed on the upper surface of the pressure receiving portion 2 and the cylindrical portion around the pressure receiving portion 2, the skin 12 is illustrated while the force P is applied by repeatedly gripping. To be damaged. Therefore, this corner 11 is caught on the object to be grasped,
The robot couldn't move smoothly. Here, 13 is the above-mentioned flexible wiring board.

The object of the present invention is to pay attention to the above-mentioned conventional problems, and in order to solve the problems, it is possible to obtain a uniform joint of pressure receiving portions to a plurality of sensor cells at the same time, which reduces the manufacturing cost and ensures stable operation of the robot. (EN) Provided is a reliable tactile sensor manufacturing method.

[Means for Solving the Problems] In order to achieve such an object, the present invention provides a matrix of sensor cells each having a pressure receiving portion protruding from the upper surface and a plurality of strain gauges formed around the pressure receiving portion. In disposing the pressure-receiving portion in the sensor cell of the tactile sensor arranged to detect the force transmitted to the sensor cell via the pressure-receiving portion via the strain gauges, a plurality of sensor cells are provided. After forming a weldable metal vapor deposition layer having a recess at the position where the pressure receiving portion of each sensor cell is formed on a configurable wafer, and injecting flux into each recess of the metal vapor deposition layer, a metal ball is placed on each recess. And heating the wafer to melt the metal vapor deposition layer to fix each of the metal spheres to the pressure receiving portion forming position of each of the sensor cells. Is formed on the wafer at the same time.

[Operation] According to the present invention, a metal ball is placed in each of the recesses of the weldable metal vapor deposition layer provided at the pressure receiving portion forming position of each sensor cell on the wafer by a semiconductor process or the like to heat the wafer to deposit the vapor deposition layer. Is melted and a plurality of metal balls are fixed at the same time to form the pressure receiving portion, so that workability is good and the manufacturing cost can be reduced. Further, since the head of the pressure receiving portion is spherical, the epidermis will not be broken, and stable robot operation will be possible.

[Examples] Examples of the present invention will be described in detail and specifically below with reference to the drawings.

FIG. 1 shows a cross section of a wafer in a portion where a pressure receiving portion of a tactile sensor is joined, according to an embodiment of the present invention. here,
By a semiconductor process, a metal vapor deposition layer (not shown), a semiconductor strain gauge, a wiring pattern, a copper vapor deposition film 10 and a solder layer 102, etc. formed at the joint portion of the pressure receiving portion are formed on the upper surface of the wafer 101 constituting the sensor cell 1. It is formed first. FIG. 2 shows one sensor cell of the tactile sensor by extracting it. Here, 102 denotes the above-mentioned solder layer, and the solder layer 102 is formed in contact with the copper vapor deposition film 10 in order to join the pressure receiving portion that transmits force to the central portion of the sensor cell 1 , and its center A cylindrical recess 103 is provided in the section.

The copper vapor deposition film 10 and the solder layer 102 having the recess 103 formed on the wafer 101 in this manner are placed on the heater 6 as shown in the left side (A) of FIG. Here, 104 and 105 are tables (hereinafter referred to as an X table and a Y table) that are movable in the X and Y directions orthogonal to each other, respectively, and the wafer 101 placed on them via the heater 6. Can be moved in a direction parallel to the paper surface and in a direction perpendicular to the paper surface.

Reference numeral 106 denotes a vacuum chuck for holding the wafer 101, which is provided on the heater 6, and 107, a syringe which accommodates the flux 108 so as to drip freely and which can be lowered in the direction of the arrow, by operating the X table 104 and the Y table 105. Wafer 101
Each time the upper solder layer 102 is moved below the cylinder 107, it drops and drops a few drops of flux 108 into the recess 1 of the solder layer.
03 Drop on top. FIG. 4 shows a state in which the flux 108 has been dropped on one sensor cell 1 in this way. The wafer 101 after the dropping of the flux 108 is completed, for example, from the position of FIG. Is moved in the direction of the arrow X by one sensor cell and is set at the position (B).

In FIG. 3B, 110 is a suction holding member that can stand by immediately above the concave portion 103 of the solder layer at this set position, and holds the metallic sphere 111 by suction, for example, at its tip 110A. This metal sphere (hereinafter referred to as a metal sphere) 111 is fixed and forms a pressure receiving portion as described later, and as long as it is a material that can be welded to the copper vapor deposition film 10 by melting the solder layer 102, It may be formed of any material. Thus, when the wafer 101 is moved to the position of (B), the metal is removed from the adsorption holding member 110 on the concave portion 103 of the solder layer in the state as shown in FIG. A ball 111 is placed. FIG. 5 shows a state in which the metal spheres 111 thus stick their bottoms into the recesses 103 of the solder layer and the surroundings are filled with the flux 108.

Thus, the X table 104 and the Y table 105 are appropriately moved, and the heater 6 is heated in a nitrogen gas atmosphere when a plurality of metal balls 111 are vertically and horizontally arranged on one wafer 101 by repeating the above operation. Here, since the heater 6 is heated to a temperature sufficient to melt the solder layer 102, the metal spheres 111 are provided on the copper vapor deposition film 1 provided at the positions of the pressure receiving portions.
It can be fixed on each of the 0. FIG. 6 shows a state in which the metal spheres 111 are fixed on the wafer 101. From this state, the elastic floor 5 is further adhered to the lower surface side, and each metal sphere 111 is located at the center of the sensor cell 1. As described above, the wafer 101 may be cut into a lattice shape with the dicing saw 112 or the like.

FIG. 7 shows a state in which the metal sphere 111 is fixed on each sensor cell 1 and functions as a pressure receiving portion thereof, and 102A is molten solder. Further, FIG. 8 shows a 1 Sensase <br/> Le 1 in an assembled finished state as the tactile sensor 100. In the figure, 13 is a flexible wiring board, and 12 is a flexible skin provided on the uppermost surface for the purpose of protection as well. Since the following manufacturing technique is the same as the conventional one, its explanation is omitted. In the tactile sensor 100 configured as described above, since the pressure receiving portion is formed by the smooth metal ball 111, even if the repeated load P as shown in FIG. It is reliable because it can be carried out continuously from the beginning using a uniform metal sphere, rather than melting the metal to form a sphere, as in A distribution of pressure receiving parts having an even joining force is obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, for each sensor cell on a wafer, a weldable metal vapor deposition layer having a recess at each pressure receiving portion forming position is formed, and each recess is formed. After injecting the flux into the wafer, place the metal spheres on each and heat the wafer to melt the metal vapor deposition layers all together and fix the metal spheres to the pressure-receiving portion forming position. Not only can it be formed accurately in the process, but it is possible to work continuously until the formation of the pressure receiving portion later, and it is possible to obtain a tactile sensor with a uniform joining force at a low cost, and to improve reliability. It can greatly contribute to the creation of robots that can perform certain stable operations.

[Brief description of drawings]

1 and 2 are cross-sectional views and perspective views of a sensor cell in one process of the present invention, and FIG. 3 is an explanatory view showing the next metal ball bonding step from the state shown in FIGS. 1 and 2 of the present invention. 4 and 5 are sectional views showing a flux coating state and a metal ball mounting state in the step shown in FIG. 3 of the present invention, and FIG. 6 is an explanatory view showing a metal ball bonding state according to the present invention, FIG. 7 is a perspective view showing a cut-out state of one sensor cell according to the present invention, FIG. 8 is a sectional view showing a completed state of the tactile sensor according to the present invention, and FIG. 9 shows an example of a conventional tactile sensor. FIG. 10 is a plan view and a perspective view of a sensor cell of a conventional tactile sensor, FIG. 12 is a configuration diagram of a circuit incorporated in the sensor cell of the tactile sensor of FIG. 10, and FIG. Explanatory drawing of pressure receiving part forming operation, Fig. 14 is a problem due to conventional example It is sectional drawing which shows an example of a state. 1 ... Sensor cell, 4 ... Bump electrode, 5 ... Elastic floor,
6 ... Heater, 12 ... Skin, 13 ... Flexible wiring board, 10 ... Copper deposition film, 100 ... Tactile sensor, 101 ... Wafer, 102 ... Solder layer, 102A ... Solder, 103 ... Recess ,
108 …… Flux, 111 …… Metallic sphere.

Claims (1)

[Claims] 1. A sensor cell having a pressure receiving portion projecting from an upper surface and a plurality of strain gauges formed around the pressure receiving portion is arranged in a matrix, and is transmitted to the sensor cell via the pressure receiving portion. In providing the pressure receiving portion in the sensor cell of the tactile sensor configured to detect the force through the plurality of strain gauges, the pressure receiving portion of each sensor cell on the wafer in which the plurality of sensor cells can be configured is formed at the position where the pressure receiving portion is formed. After forming a weldable metal vapor deposition layer having a recess, injecting flux into each recess of the metal vapor deposition layer, placing a metal sphere on each recess, and heating the wafer, the metal vapor deposition layer Is melted to fix each of the metal balls to the pressure-receiving portion forming position of each sensor cell, and a plurality of pressure-receiving portions made of the metal balls are simultaneously formed on the wafer. Method for manufacturing a tactile sensor.