JPS6258661B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positioning device for semiconductor pellets (hereinafter referred to as pellets).

Generally, to make semiconductor devices (such as LSI), pellets are first fixed to the pellet attachment part of a lead frame using ultrasonic waves, etc., but before the pellets are transferred to the pellet attachment part, a number of pellets are first fixed. The pellets are transferred one by one from the pellet storage container in which the pellets are stored in an orderly manner to a pellet positioning device, where the pellets are positioned.Then, the pellets that have been positioned by this positioning device are transferred to a collet having a lower end pellet suction section. The pellets are sucked up and transferred to the pellet attachment section of the lead frame.

This is because the collet makes a constant reciprocating motion and only ejects the pellets adsorbed at the lower end to the pellet attachment part, so that when the pellets are released, they are placed correctly in the pellet attachment part of the lead frame. This is because the position of the pellet to be adsorbed to the collet is determined in advance by a positioning device.

However, these pellets come in a variety of sizes, and pellets of a fixed size are not always transferred to the lead frame. For example, in the case of a hybrid type, pellets of different sizes or even square shapes are transferred. In addition, rectangular pellets must be sequentially transferred to the pellet mounting section.

Therefore, the present invention provides a method for positioning semiconductor pellets that can not only be used to sequentially transfer pellets of a certain size to a pellet mounting section, but also meet the requirements for sequentially transferring pellets of different sizes and shapes as described above. The purpose is to provide equipment.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a pellet positioning device showing an embodiment of the present invention, and FIG.
A cross-sectional view is shown.

In the figure, reference numeral 1 denotes a base plate, and a pellet mounting table 2 is provided on the base plate 1. 3, 3', 4,
Reference numeral 4' denotes guide grooves, and a total of 4 guide grooves are formed on the base plate 1, radially in two directions perpendicular to the center of the pellet mounting table 2, that is, in the X and Y directions in FIG.
There are several. Note that since the configuration is the same in both the X direction and the Y direction, only the X direction will be described below. In the guide grooves 3, 3', pellet positioning bodies 6, 6', each having pellet holding jaws 5, 5' on the upper surface for positioning the pellet A placed on the pellet mounting table 2, are slidably provided. Shafts 7, 7' are protruded from the lower surfaces of the pellet positioning bodies 6, 6' (in FIG. 2), and rollers 8, 8' are rotatably held on these shafts. 9
10 is a fixed shaft attached to the platform 1 in the vertical direction below the center of the pellet mounting table 2, and 10 is a fixed shaft that is attached to the pellet positioning body 6, 6' in the X direction from opposite directions, or It is a hollow shaft having a cam 11 for separating the pellets, and is rotatably attached to a fixed shaft 9. On the cam surface of this cam 11, pellet positioning bodies 6, 6' and fixed pieces 12, 1 are attached.
2', a coil spring 13 provided between
13' allows the rollers 8, 8' to come into resilient contact. 14 is a gear integrally provided at 10a with a set screw on the hollow shaft 10, and this gear 14 is connected to a pulse motor 15 attached to the base plate 1.
It is meshed with a gear 17 fixed to an output shaft 16 of. Reference numeral 18 denotes a gear having a cam 20 that allows pellet positioning bodies 19 and 19' arranged in the Y direction in FIG. 1 to approach each other from opposite directions or to separate them from each other in opposite directions. This gear 18 is freely provided, and similarly to the configuration in the X direction, this gear 18 meshes with a gear fixed to the output shaft of a pulse motor 21 attached to the base plate 1. Note that FIG. 3 shows the positional relationship between the cams 11 and 20.
Reference numeral 22 denotes a disk having a slit etc. provided on the output shaft 16 of the pulse motor 15, and a detector 23 that holds the disk 22 and detects the rotation angle of the output shaft 16.
The detector 23 is connected to a pulse motor control device (not shown).

Next, the operation of the above configuration will be explained.

Note that since the X and Y directions are the same, only the X direction will be explained.

First, pellets A are placed one by one from the wafer storage container onto the pellet mounting table 2. At this time, the gap between the pellet holding jaws 5 and 5' is set to be sufficient to allow the pellet A to be placed thereon. Next, a pulse motor from a pulse motor control device (not shown)
The output shaft 16 of the pulse motor 15 is activated by the ON command.
starts rotating counterclockwise in FIG. This rotation is caused by the third cam 11 via the gears 17 and 14.
By rotating clockwise in the figure, the rollers 8, 8' in contact with the cam 11 follow the cam surface of the cam 11, and the pellet positioning body 6,
6' start moving toward the pellet mounting table 2. Also in the Y direction, the cam 20 rotates in the same direction as the cam 11 via the gear 18 from the gear fixed to the output shaft of the pulse motor 21, and the pellet positioning bodies 19, 19' also move toward the pellet mounting table 2. Start. The rotation angle of the output shaft 16 of the pulse motor 15 is equal to the rotation angle of the disc 22, and the detector 23 detects the rotation angle of the disc 22. This detection signal is inputted at any time to a pulse motor control device (not shown). Further, the pulse motor control device determines the angle at which the output shaft 16 of the pulse motor 15 should be rotated, that is, a value corresponding to the pellet clamping interval m shown in FIG. The clamping interval m itself can be numerically set in advance, and based on this set value and the detection signal from the detector 23, the interval between the pellet clamping jaws 5 and 5' is set to the clamping interval m.
When this happens, an OFF signal is given to the pulse motor 15. When an OFF signal is given from the pulse motor control device, pulse motor 1
5 stops the output shaft 16, that is, stops the rotation of the cam 11, whereby the pellet positioning bodies 6, 6' are moved by the same amount until the distance between the pellet holding jaws 5, 5' becomes m, and then stopped. do. At this stage, the pellets placed on the pellet table 2 are accurately positioned by the pellet clamping jaws 5, 5'. After positioning, the pellet positioning bodies 6, 6' are separated from each other in opposite directions and returned to their initial positions by the reverse rotation of the pulse motor 15, and the pellets that have been positioned are picked up by a well-known collect. , and transferred to the pellet attachment part of the lead frame.

The above embodiment has the following effects. That is, the pellet positioning bodies 6, 6', 19, 19' are moved by the cams 11, 20 rotated by the pulse motors 15, 21 via the rollers 8, 8'. By changing the rotation angle of the pellet 20, the pellet clamping interval m can be easily set and changed.
Since the cams 20 for moving the positioning bodies 19 and 19' in the 1 and Y directions are separately provided and rotated by separate pulse motors 15 and 21, respectively, the pellet clamping interval m can be adjusted orthogonally on the pellet mounting table 2. If the distances are set the same in the two directions, square pellets can be positioned, and if they are set at different intervals, rectangular pellets can also be positioned. Also, at that time, the pair of pellet positioning bodies 6, 6', 19, 19'
1 and 20, the pellets move by the same amount in the X direction or in the Y direction, so regardless of their size and shape, the pellets that have been positioned will have their center (intersection of two diagonal lines) approximately on the pellet mounting table 2. It can be kept constant. Furthermore, when the pellet positioning bodies 6, 6', 19, 19' approach, the respective pellet holding jaws 5,
When the interval 5' reaches the preset pellet clamping interval corresponding to the pellet A to be positioned,
By stopping the rotation of the cams 11 and 20, the subsequent movement is stopped, so that the pellet A can be accurately positioned without applying any unnecessary clamping force to the pellet A during positioning.

Furthermore, the pellet clamping interval m can be easily changed by simply controlling the rotation angles of the pulse motors 15 and 21 using the pulse motor control device. positioning can be performed.

Furthermore, pellet positioning bodies 6, 6', 19, 1
9' is always pressed toward the center of the pellet mounting table 2 by coil springs 13, 13' and is not fixed to any member, so even if there is an error in pellet size, the spring 13,13' absorbs and pellet A
This prevents excessive force from being applied to the

Furthermore, the cams 11 and 20 are driven by pulse motors 15 and 2.
Since the rotation is made by cam 11,
If the pellet clamping jaws 5, 5' are set to rotate quickly at first and then slow down when the distance between the pellet clamping jaws 5, 5' approaches the pellet clamping distance m, the pellet clamping jaws 5, 5' can The movement up to contact can be performed in a short time.

In the above embodiment, a pulse motor is used as the rotational drive source for the cams 11 and 20. However, a stepping motor, a stepping motor, a digital motor, etc., which can set the rotation angle of the cams 11 and 20, may be used. But it can be applied.

As explained above, according to the present invention, accurate positioning can be performed regardless of the size and shape of the semiconductor pellet, and the center position of the positioned semiconductor pellet can be kept almost constant on the pellet mounting table. Furthermore, no excessive clamping force is applied to the semiconductor pellet during positioning.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a pellet positioning device showing an embodiment of the present invention, and FIG.
The cross-sectional view, FIG. 3, is a cross-sectional view in FIG. DESCRIPTION OF SYMBOLS 1... Base board, 2... Pellet mounting table, 5, 5'... Jaws for holding pellets, 6, 6', 19, 19'... Pellet positioning body, 8, 8'... Roller, 9... Fixed shaft, 11, 20...Cam, 13, 13'...Coil spring, 15, 21...Pulse motor, 22...Disc, 23...Detector, A...Pellet.

Claims (1)

[Claims] 1. A base plate in which four guide grooves are formed radially orthogonally to each other with respect to the center of the pellet platform, a pellet positioning body slidably provided in each of the guide grooves, and the pellet platform. a first cam that is rotatable about the center of the first cam and has a cam surface that causes the opposing pair of pellet positioning bodies to approach and separate by the same amount, and the other opposing pair of pellet positioning bodies. a second cam having a cam surface that moves each pair of pellet positioning bodies toward and away from each other by the same amount;
a biasing member elastically biasing the cam surface of the cam;
A first rotational drive section that rotates the first cam in forward and reverse directions, a second rotational drive section that rotates the second cam in forward and reverse directions, and each pair of pellet positioning bodies. a control unit that controls the first and second rotational drive units so as to stop the movement of the semiconductor pellets when a preset clamping interval corresponding to the semiconductor pellets placed on the pellet mounting table is reached when approaching the pellets; A semiconductor pellet positioning device comprising: