JPH03293531A - Manufacture of tactile sensor - Google Patents

Abstract

PURPOSE:To achieve a higher reliability along with a reduction in production cost by a method wherein metal spherical bodies are placed on recess of a metal deposited provided at positions of forming a pressure receiving section of sensor cells on a wafer and the deposited layer is melted by heating the wafer to form the pressure receiving sections with the fastening of a plurality of metal spherical bodies simultaneously. CONSTITUTION:A wafer 101 in which a solder layer 102 having a copper deposited film 10 and a recess 103 thereon is formed per sensor cell is placed on a heater 6 as indicated by (A). Each time the solder layer 102 on the wafer 101 moves by the operation of an X table 104 and a Y table 105, a syringe 107 lowers to drop a flux 108 on the recess 103. As the wafer 101 moves to a position (B), a metal spherical body 111 is put onto the recess 103 from an absorption holding member 110. By repeating the above operation, the solder layer 102 is raised to a temperature high enough to be melted with the heater 6 as a plurality of the spherical bodies 111 are arranged on the wafer 101. Thus, the spherical bodies 111 can be fastened on the copper deposited films 10 provided at the positions of the pressure receiving sections respectively.

Description

Detailed Description of the Invention [Industrial Application 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 part is attached to each sensor cell. The present invention relates to a method for manufacturing a tactile sensor suitable for use by being attached to a robot hand, etc., and capable of detecting force applied through a robot hand.

[Conventional technology] Conventional robots are often driven by sequence control or open-loop control, and work is performed in a specific and limited environment, so there are limits to the content of the work and the capabilities of the robot. Ta. For example, in the case of big-and-place robots, parts are placed during assembly line work, and the robot is limited to a series of specific movements such as gripping a specific part, and the function is to select and grip dissimilar parts. does not have. However, recently, as robots have become more intelligent, visual sensors and tactile sensors that correspond to human senses have been developed, and robots that can operate in various environments are being put into practical use.

A distributed tactile sensor is a sensor for such an intelligent robot. Such a sensor is attached to a robot hand, etc., and when the robot hand grips an object, it detects the signal obtained from the sensor and performs feedback control to control the gripping force of the object or recognize the hardness of the object. It 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 B that intersect with each other at right angles are combined in two layers, and the area of the contact portion of the rubber strips increases due to the force applied perpendicularly to the surface where the rubber strips are arranged. , the magnitude of the applied force can be determined by detecting changes in resistance. However, such a tactile sensor has the disadvantage that it cannot provide an output proportional to the applied force, resulting in a nonlinear output, and is not suitable for detecting force distribution in a high density.

In order to solve the above-mentioned drawbacks, a tactile sensor as shown in Nos. 10 to 12U has been developed. In FIGS. , 3A to 3D are semiconductor strain gauges arranged around the pressure receiving part 2 above the sensor cell and used to detect the strain occurring in the sensor cell 1; (The bump electrode 5 disposed on the sensor cell 1 is an elastic bed that holds the sensor cell 1 and acts as an elastic body.

Here, the semiconductor strain gauges 38 to 3D are incorporated in a Wheatstone bridge circuit as shown in FIG. 12, and the sensor cell 1
The force applied to the semiconductor strain gauges 3A to 3D is detected as a strain value by supplying power (V) to the bridge circuit, and the output signals from the semiconductor strain gauges 3A to 3D are transmitted through the bump electrode 4 and a flexible wiring board (not shown). Can be taken outside.

[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 part on the sensor cell, a flexible wiring board (not shown), and a skin covering these, etc. There was a problem with the joining method and shape of this sensor cell and the pressure receiving part.

That is, FIG. 13 shows the operation when such a conventional pressure receiving part is provided on a sensor cell, in which the sensor cell is placed on a heated heater 6 and the pressure receiving part 2 is held with a bottle set 7. Apply flux 8 to the bottom surface of the top,
Furthermore, a solder pellet 9 is attached via a flux 8, and while keeping the shape as shown in the figure, it is lowered in the direction of the arrow and manually placed on the vapor deposited film 10 of, for example, copper, which is formed on the upper surface of the sensor cell. The solder pellets 9 were melted by the heat of the heater 6 and joined together.

However, when joining by such a method, not only the positional accuracy of the pressure receiving part 2 with respect to the center on the sensor cell or the perpendicularity to the plane on the sensor cell become irregular, but also the workability is poor and the manufacturing cost is high.

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 it, as the force P is applied by repeated gripping, the outer skin 12 will change as shown in the figure. to be damaged. As a result, the corner 11 got caught on the object to be grasped, making it impossible for the robot to move smoothly. Note that here, 13 is the aforementioned flexible wiring board.

The purpose of the present invention is to focus on the above-mentioned conventional problems and to solve the problems, it is possible to uniformly bond pressure receiving parts to a plurality of sensor cells at the same time in +y'c, reduce manufacturing costs, and improve stable robot operation. An object of the present invention is to provide a method for manufacturing a tactile sensor that is guaranteed and highly reliable.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a sensor cell having a pressure receiving part protruding from the upper surface and a plurality of strain gauges formed around the pressure receiving part in a matrix shape. In providing the pressure receiving section in the sensor cell of the tactile sensor, the force transmitted to the sensor cell via the pressure receiving section is detected through the plurality of strain gauges, A weldable metal vapor deposition layer having a recess is formed at the formation position of the pressure receiving part of each sensor cell on a configurable wafer, and after injecting flux into each recess of the metal vapor deposition layer, a metal sphere is placed on each recess. is placed on the wafer, and the metal vapor deposited layer is melted by heating the wafer, thereby fixing each of the metal spheres to the pressure receiving part formation position of each of the sensor cells, and the plurality of pressure receiving parts made of the metal balls are placed on the wafer. It is characterized in that it is formed simultaneously on the top.

1 Effect] According to the present invention, metal balls are placed in the recesses of the weldable metal vapor deposition layer provided at the pressure receiving part formation position of each sensor cell on the wafer by a semiconductor process, etc., the wafer is heated, and the vapor deposition is performed. Since the pressure receiving part is formed by melting the metal balls in layers and simultaneously fixing a plurality of metal balls, the workability is good and the manufacturing cost can be reduced. Furthermore, since the head of the pressure receiving part is spherical, the skin will not be torn, and stable robot operation will be possible.

[Examples] Examples of the present invention will be described below in detail and specifically based on the drawings.

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

In this way, the copper deposited film 108 on the wafer 101 and the recess 1
A solder layer 102 having a solder layer 102 having a solder layer 102 formed in each sensor cell is placed on the heater 6 as shown on the left side (A) of FIG. Note that 104 and 105 are tables (
These are referred to as X tables and Y tables hereinafter), and the wafer lO1 placed thereon can be moved in a direction parallel to the plane of the paper and in a direction perpendicular to the plane of the paper via the heater 6.

106 is a vacuum chuck provided in the heater 6 to hold the wafer 101; 107 is a flux 108;
The syringe is a syringe that can be freely housed for dripping and can be freely lowered in the direction of the arrow, and the beam layer 102 on the wafer 101 is moved into the syringe 1 by operating the X table 104 and the Y table 105.
Each time it is moved below 07, it descends and drops several drops of flux 108 onto the recess 103 of the solder layer. FIG. 4 shows the state in which the flux 108 is dropped onto one sensor cell 1 in this way.
The wafer 101 on which No. 08 has been dropped is moved from the position shown in FIG. 3A by one sensor cell in the direction of the arrow X by, for example, the X table 104, and set at the position shown in FIG. 3B.

In FIG. 3(B), reference numeral 110 denotes a suction holding member that can stand by directly above the recess 103 of the solder layer at this set position, and a metal sphere 111 is attached to its tip 110A.
For example, by suctioning and holding. This metal sphere (hereinafter referred to as a metal sphere) 111 is fixed as described later to form a pressure receiving part, and any material can be used as long as it can be welded to the copper vapor deposited film lO by melting the solder layer 102. It may be made of any material. (Then, when the wafer 101 is moved to the position (B), the flux 108 is first
A metal ball 111 is placed from an adsorption/holding member 110 onto the concave portion 103 of the solder layer, which is in the state shown in FIG. FIG. 5 shows the state in which the metal ball 111 has its bottom stuck in the recess 103 of the solder layer and the surrounding area is filled with flux 108.

In this way, the X table 104 and the Y table 105 are moved appropriately, and the above-described operations are repeated to heat the heater 6 in a nitrogen gas atmosphere when a plurality of metal balls 111 are arranged vertically and horizontally on one wafer lot. Here, the temperature of the heater 6 is raised to a temperature sufficient to melt the solder layer 102, so that the metal balls 111 can be fixed on the copper vapor deposited films 10 provided at the positions of the respective pressure receiving parts. FIG. 6 shows a state in which metal balls 111 are fixed on the wafer 101. From this state, an elastic floor 5 is further bonded to the lower surface side of the wafer 101, and each metal ball 111 is positioned at the center of the sensor cell. Guishingtu-11
The wafer 101 may be cut into a grid pattern using a cutting tool such as No. 2 or the like.

FIG. 7 shows a state in which a metal ball 111 is fixed onto each sensor cell and functions as a pressure receiving part, and 102A is molten solder.

Moreover, FIG. 8 shows the top of one sensor cell in a completed state assembled as the tactile sensor 100. In the figure, reference numeral 13 indicates a flexible wiring board, and I2 indicates a flexible skin provided on the top surface for protection.The following manufacturing techniques are the same as conventional ones, so their explanation will be omitted. In the tactile sensor 100 configured in this way, the pressure receiving part is formed of the smooth metal ball 111, so even if a repeated load P as shown in the figure is applied through the skin 12 due to an object being held, for example, the skin 12 is It is reliable because it does not break like in conventional methods, and the pressure-receiving part can be formed continuously using uniform metal spheres from the beginning instead of melting the metal into spheres. A distribution of pressure receiving parts with uniform bonding force can be obtained.

Effects of the Invention As described above, according to the present invention, a weldable metal vapor deposition layer having a recess at each pressure receiving part forming position is formed on each sensor cell on a wafer, and each recess After injecting flux into the wafer, a metal ball is placed on each wafer and the wafer is heated, melting the metal vapor deposited layer at the same time and fixing each metal ball to the position where the pressure receiving part is formed. Not only can it be formed with high precision using a semiconductor process, but it also enables continuous work up to the formation of the pressure-receiving part, making it possible to obtain a tactile sensor with uniform bonding force at a low cost, and improving reliability. This can greatly contribute to the creation of robots that can perform stable movements.

[Brief explanation of the drawing]

1 and 2 are a cross-sectional view and a perspective view of a sensor cell in one process of the present invention, and FIG. 3 is an explanatory diagram showing the next metal ball joining process from the state shown in FIGS. 1 and 2 of the present invention. , FIG. 4 and FIG. S are sectional views showing the flux application state and metal ball mounting state in the process shown in FIG. 3 of the present invention, and FIG. 6 is an explanatory diagram showing the metal ball joining state according to the 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 is an example of a conventional tactile sensor. FIG. 1O and FIG. 11 are 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. 1O, and FIG. 13 is a conventional tactile sensor. FIG. 14 is a cross-sectional view showing an example of a defective state according to the conventional example. DESCRIPTION OF SYMBOLS 1... Sensor cell, 4... Bump electrode, 5... Elastic floor, 6... Heater, 12... Skin, 13... Flexible wiring board, lO... Copper vapor deposition film, 100... ...Tactile sensor, 101...Wafer, 102...Solder layer, 102A...Solder, 103...Concave portion, 108...Flux, 111...Metal ball.

Claims (1)

[Claims] Sensor cells each having a pressure receiving part protruding from an upper surface and a plurality of strain gauges formed around the pressure receiving part are arranged in a matrix, and transmission is transmitted to the sensor cells via the pressure receiving part. In providing the pressure receiving part in the sensor cell of the tactile sensor configured to detect the applied force through the plurality of strain gauges, the formation position of the pressure receiving part of each sensor cell on a wafer in which a plurality of the sensor cells can be configured. forming a weldable metal vapor deposition layer having recesses in the metal vapor deposition layer, injecting flux into each recess of the metal vapor deposition layer, placing a metal ball on each of the recesses, and heating the wafer to perform the metal vapor deposition. A method for manufacturing a tactile sensor, comprising: melting a layer to fix each of the metal balls to a pressure receiving part forming position of each of the sensor cells, and simultaneously forming a plurality of pressure receiving parts made of the metal balls on the wafer. .