JPS6144638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a hand portion of an assembly robot or the like that grips an object, particularly a structure of a robot hand suitable for handling small parts such as in the assembly process of semiconductor devices. Regarding.

(b) Background of the technology In die bonding work, which is one of the assembling processes for semiconductor devices, conventionally, as shown in Fig. 1, semiconductor device pellets 2 are
After vacuum adsorption, the pellet 2 is placed in the gold-plated cavity 4 on the lead frame 3, and the pellet 2 is placed at a temperature higher than the gold-silicon eutectic temperature.
The pellet 2 is bonded to the lead frame 3 using a gold-silicon eutectic alloy.
By the way, if the size of the pellet 2 changes, it is necessary to replace and adjust the collet 1 accordingly. As semiconductor products are produced in high-mix, low-volume production, the setup time required for replacing and adjusting the collector 1 becomes a problem. In addition, as the pellets 2 have become larger in recent years, the area occupied by the pellets 2 in the cavity 4 has increased, and when the pellets 1 are used,
The protruding part of the collect 1 gets in the way and makes scrubbing work difficult.

(c) Prior art and its problems For this reason, in the past, when producing in small quantities or when pellets are large, the work has been done manually using tweezers.

If an opening/closing type robot hand is used, even if the product type changes, it can be handled by simply changing the amount of opening/closing using the same robot hand, and there is almost no setup involved in changing the product type. Furthermore, even if the pellets become large, they can be scrubbed more easily than in the case of pellets by scrubbing in a direction perpendicular to the opening/closing direction.

However, in order to perform die bonding work using a robot hand in this manner, the following conditions are required.

(1) Small size and large gripping force.

When scrubbing, a pressing force of about 100% is usually applied. Therefore, a greater force is required as a gripping force, which is much larger than the pellet's own weight (1 g or less).

(2) Capable of minute positioning.

When opening the fingers after scrubbing, minute positioning is required so that the fingers do not hit the lead frame.

(3) The structure must be flexible in the pressing direction so that an appropriate pressing force can be applied to the pellet, and the gripping force and pressing force can be adjusted to increase the reliability of the operation, and when the pellet is dropped after gripping. In addition, it is required to be able to detect this, and to be able to detect when the nail slips off the pellet during scrubbing.

(d) Object of the Invention The object of the present invention is to realize a robot hand that can meet these requirements necessary when handling small parts such as semiconductor pellets.

(e) Structure of the invention In order to achieve the above object, the present invention has the following features:
The frame of the robot hand is attached to the arm via a parallel spring made of two parallel plate springs, and two tweezers-type fingers, at least a part of which is made of plate springs, are attached to the frame on one side. In addition to being attached in a beam-carrying manner, a release for opening and closing the finger is provided, and a drive section for driving the release in response to an input drive signal is mounted on the arm side.

(f) Embodiments of the Invention Next, examples will explain how the robot hand according to the present invention is actually implemented. Second
The figures show an embodiment of the robot hand, in which A is a plan view, B is a front view, and C is a right side view. 5 is the arm of the robot hand, the tip of which is T-shaped. 6 is the frame of the hand part, and the horizontal part 6
a, and release holding arms 6b and 6c hanging down from both ends thereof. The T-shaped hand attachment portion 5a at the tip of the arm and the horizontal portion 6a of the frame are connected in symmetrical positions by parallel springs 7a and 7b and parallel springs 7a' and 7b' so that they are parallel to each other. . That is, on the left side of the figure, an upper leaf spring 7a and a lower leaf spring 7b face each other horizontally, one end of each is fixed to the arm attachment part 5a, and the other end is fixed to the horizontal part 6a of the frame. ing. Similarly, on the right side of the figure, an upper leaf spring 7a' and a lower leaf spring 7b' face each other in parallel, one end of each is fixed to the arm attachment part 5a, and the other end is fixed to the horizontal part 6a of the frame. Fixed. A support member 8 extends from the lower surface of the arm 5 to the lower side of the horizontal part 6a of the frame, and extends above the protrusion 8a to the horizontal part 6a.
is mounted and supported. Strain gauges S11 and S12 are attached to both sides of one end of the parallel spring 7a'.

In addition, in the horizontal part 6a, there is a tweezers shaped 2
The upper ends of fingers F ₁ and F ₂ are fixed. Finger F ₁ ,
F ₂ is also composed of leaf springs, and they are parallel to each other and face each other. Strain gauges S21 and S22 are attached to both sides of one finger F ₂ , and claws 91 and 92 for gripping objects are provided at the lower ends of fingers F ₁ and F ₂ .

Reference numeral 10 denotes a release whose outer cylinder 10a has one end attached to the release holding arm 6c of the frame, and the other end attached to the main body 11a of the drive means 11. Further, one end 10b of the core wire of the release passes through the release holding arm 6c of the frame and is closely opposed to the finger _F2 , and the other end 10b' is connected to the movable portion 11b of the drive means 11. The shutter on the left side of the figure is similarly attached between the finger F ₁ and the release holding arm 6b on the left side, and the main body 11a of the driving means 11 and the movable part 11b. Therefore, one drive means can drive two releases.

Next, the operation of the robot hand will be explained. FIG. 3 shows the pellet being held so that it can be scrubbed. When not gripping an object such as a pellet, use the horizontal part 6a of the frame as shown in Figure 2.
However, the protrusion 8a of the support member 8 extending from the arm 5
It is supported and positioned on top. finger
When an object to be gripped, for example a pellet 2, arrives below F ₁ and F ₂ , the frame 6 is lowered by the device main body 12 . And the claws 91 and 92 are pellets 2
When the drive source 11 such as a pulse motor is activated, the core wires 10b of the two releases are lowered to both sides.
10b is pushed out toward the fingers F ₁ and F ₂ to narrow the gap between the fingers F ₁ and F ₂ , and the pellet 2 is held between the nails. At this time, finger F ₁ ,
Since _F2 is made of a leaf spring, it flexes, and the gripping force of the pellet 2 is detected by detecting the amount of flexure using strain gauges S21 and S22. When the gripping force reaches the set value, the driving means 11 stops and the core line 10 of the release is moved as shown in Fig. 3A.
b and 10b stop with fingers F ₁ and F ₂ pressed. Next, the frame 6 is further lowered by the main body 12 of the apparatus, and the pellets 2 are pressed against the cavity 4 of the lead frame 3 and scrubbed. The pressing force at this time is detected by strain gauges S11 and S12 of the parallel spring 7a'. That is, when the pellet 2 being held is pressed against the cavity 4, the parallel springs 7a, 7b, 7a', 7 are released as shown in FIG.
The arm side end of b' moves downward in parallel. At this time, the strain gauges S11 and S12 are distorted and the resistance value changes, so the pressing force of the pellet 2 is detected based on the amount of deflection of each parallel spring. Strain gauges are used at locations where large bending moments occur.
That is, it is desirable to attach it to a position close to the end of the parallel spring. Although a strain gauge is used as an example of the detection element, a so-called gap sensor or the like may also be used as long as it can detect displacement optically or electrically.

The scrubbing of pellet 2 is as shown in Fig. 3A.
By performing the scrubbing in the direction perpendicular to the plane of the paper instead of in the direction of the plane of the paper, even if the size of the pellet 2 is large relative to the cavity 4, sufficient scrubbing can be achieved.

When the scrubbing is completed, the driving means 11 is reversed to retract the core wires 10b, 10b of the release.
Then, fingers F ₁ and F ₂ return to their original states shown in FIG. 2 by their own spring force. The release 10 is connected to a core wire 10b by a preload spring 10c as shown in FIG.
is pressed toward the driving means to prevent the core wire 10b from pressing the fingers F ₁ and F ₂ and to prevent play from occurring except when being driven by the driving means.
Note that 10d is an inner coil, and 10e is an outer coil.

(g) Effects of the Invention As described above, according to the present invention, the frame to which the fingers of the robot hand are attached is attached to the arm via a parallel spring made up of two parallel leaf springs facing each other. , pellets, and other objects are pressed against a cavity or the like via a spring, resulting in a flexible structure. By attaching a detection element such as a strain gauge to the parallel spring, the pressing force can be easily detected and adjusted.
The fingers that grip the object are also made up of leaf springs, in whole or in part, so that they can grip the object elastically, without the risk of damaging the object, and can be fitted with strain gauges, etc. This allows you to easily detect the gripping force and grip with the optimal force. If a fingernail becomes detached from an object or an object falls while performing a task such as scrubbing, the finger returns to its original state and can be easily detected with a finger strain gauge. can.

In addition, the fingers are shaped like cantilevered tweezers, so the stroke of the fingertips can be sufficiently large, and it can be easily inserted into small gaps.The fingers are operated by the release, and the release is driven by a pulse motor. For example, it is possible to control the amount of opening and closing of the fingers with high precision to perform minute positioning, and to obtain a sufficiently large gripping force. In particular, the device is configured so that the finger can be used to open and close the release from a remote position, and the drive unit that drives the release based on the input drive signal is mounted on the arm side, which is separate from the hand side. . Therefore, the weight of the hand side is reduced, making it suitable for controlling subtle pressing forces when mounted on a robot.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional semiconductor pellet scrubbing device, Fig. 2 and the following shows an embodiment of the robot hand according to the present invention, Fig. 2 is a diagram in a normal state, and Fig. 3 is a diagram showing a robot hand gripping an object. A diagram of the state in which
FIG. 4 is a sectional view of the release. In the figure, 2 is a pellet, 5 is an arm, 6 is a frame, 6a is a horizontal part, 6b, 6c are release holding arms, 7a, 7b, 7a', 7b' are parallel springs,
F ₁ and F ₂ are fingers, 10 is a release, and 10a is a core line of the release.

Claims (1)

[Claims] 1 The frame of the robot hand is attached to the arm via a parallel spring made of two parallel plate springs facing each other, and two tweezers-type fingers, at least a part of which is composed of plate springs, are attached to the frame. A robot hand characterized in that it is mounted in a cantilevered manner, is provided with a release for opening and closing the finger, and is equipped with a drive section on the arm side that drives the release in response to an input drive signal.