JPS5884436A - High speed pellet positioning system - Google Patents

Abstract

PURPOSE:To greatly shorten the total required time of the titled system, by introducing high speed continuous feeds in a positioning system wherein the mask count system for a semiconductor pellet is used. CONSTITUTION:The pellets 1 to be the object are arranged on an adhesive sheet 3 spread over a metallic ring 2 and supplied. The ring 2 is loaded on an XY or XYO table driven by a motor, and the pellet 1, after such a positioning that the center thereof may come onto the central axis of a thrust-up rod 4 and an adsorption collet 5, is tore off from the sheet 3 by the adsorption collet 5 and mounted onto a base. First, after performing a positioning and an adsorption to the first pellet, an index feed is performed to the left or right in the X direction, and the positioning is likewise performed to the next pellet. For this positioning, recognition masks shown in figures (a) and (b) are used. Among four masks for rough positioning U, D, R, L, when the number of those whereof the count number is judged as the regulated bit number or more is 0-1, it is judged that no pellets exist, and immediately an index feed is performed. Further, when the situation for the index feed is continuous 1-several times, the configuration of masks is changed into that of the figure (c), and the high speed continuous feed of the table is started.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to self-excited positioning and clamping, which is particularly sought after in semiconductor device manufacturing, especially in mounting machines that mount semiconductor pellets on bases, lead frames, etc. It is.

As shown in No. 1-, the target Pele v) 1 is placed on the adhesive sheet 3 superior to the metal layer 2! The above ring 3 is supplied in rows and is driven by X! Alternatively, the xYO tape kIc can be attached only, but the pellet 1 is positioned so that its center is on the center axis of the central lifting rod 4 and the suction collet 5, and then it is peeled off from the sheet 3 by the suction collet 5 and mounted on the base. Various methods have been proposed to date for the above-mentioned automatic pellet positioning, but these positioning algorithms always include an operation called index feeding during one cycle of pellet positioning. This is the 2nd m! An index amount lx and 17, which are approximately equal to the distance between the centers of the pellets represented in ll, are predetermined, and after the positioning for one pellet @ the suction operation is completed, only this capacitance Xt or Y-direction The above-mentioned table is moved before positioning of the next pellet is started. In all conventional pellet positioning methods, the deviation between the center position of the pellet at the start of positioning and the center at the normal position is As the tolerance range for However, it is rare that the arrangement is as shown in the figure.
The bullets are often loose or tilted, as shown in No. 3811 and No. 411. Conventionally, the following operations have been performed to position the bullets on the cap one by one. , #Is After positioning and suctioning the first pellet in the mass, perform index feeding to the left or right in the X direction, and position the next pellet in the same way.The above operation is performed at the end of the cap. This is repeated until reaching the end of the cap, and when the end of the cap is reached, the index feed is performed either upward or downward in the Y direction, and the same operation is continued with the index feed in the X direction in the opposite direction. 〇At this time, if it is determined that there are no pellets when index feeding is performed, index feeding is performed immediately. Therefore, even if there is a continuous area Km in which there is no pellet as shown in FIGS. 3116 and 4, it is necessary to carry out the index feeding in negative and negative times, and the time spent in this part is also large.

Therefore, the purpose of the present invention is to improve the positioning method using the mask counting method proposed in Japanese Patent Application No. 123271/1982, "Pellet Positioning IIM Method", and to provide high-speed pellet positioning that reduces the above-mentioned time loss. The purpose of the present invention is to propose a system in which a patterned conductor woofer pasted on an adhesive sheet is diced or scribed, and then the sheet is stretched and arranged in a matrix to be supplied. In order to sequentially peel off the conductor pellets using a suction arm and mount them on a base or lead frame, etc., the conductor pellet images are optically formed on a two-dimensional imaging system, and the video signal is transmitted over a set time. Binarization is performed by comparing the output voltage value when sampled at intervals with the set threshold value.
! After converting into an image, the amount of correction required for pellet positioning is calculated based on the binary image information, and positioning is performed by moving the drive system of the table that holds the cap on which the pellets are arranged according to the amount of correction. In the pellet positioning method that performs this, one or more squares are created as an area to limit the counting of white or black bits in a two-dimensional image that captures an area in the direction in which the next pellet to be positioned exists. - is set, and the feed mode of the table in a state where there are no continuous pellets is set as high-speed continuous feed, and whether to continue or stop the high-speed continuous feed is determined based on the count number of white or black bits □ in the mask. This is a high-speed pellet positioning method that is characterized by controlling the table drive system by using the table drive system.

Next, a detailed explanation of the present invention will be given using Figures 6 onwards.
This is a mask arrangement for light position recognition used in the specification of No. 75, and positioning is performed based on the count number of white or black bits in the mask arranged in a two-dimensional image. 1#4 Rough positioning mask U in Figure (a)
, D, R, L If the count number is determined to be equal to or greater than the specified number of bits among the 4 bits, but the number is O or 1, it is assumed that no pellet exists and index feeding is performed immediately. There is a situation where it is determined that there are no pellets and the direct consultation index is sent.
When this happens several times in a row, the arrangement of the masks is changed as shown in Figure 6 (d) and the table starts to be fed continuously at high speed. ) is set ahead of the area of the pellet e during positioning indicated by the mask P in the index feeding direction $CIIL.

When the table is continuously feeding at high speed, two-dimensional image information is constantly input at fixed time intervals, and while the count number of the preceding mask is compared with the set value, the pellet image enters the preceding mask and the set value is reached. When the distance is exceeded, the table is instructed to stop and positioning processing is performed. Figure 7)
and (r) are timing charts for the conventional table drive method and the method according to the present invention when pellets are lined up as shown in E (a). As can be seen, by introducing the high-speed continuous feed of the present invention, the total required time is greatly reduced.

FIG. 6 shows an example of a processing circuit when implementing the present invention. The video signal input from the 02-dimensional #l system passes through a binarization circuit and a mask circuit, and the white or black bits of each mask shown in FIG. converted into numerical information. Based on the information, the control circuit outputs a position correction amount or index feed, high-speed continuous feed 111#l, and stop to the table drive link, and also instructs the mask circuit to change its arrangement.

The operational problems are the position of the advance mask and mold,
Considering the disorder of the pellet arrangement, it is better to set two or more upper and lower pellets to determine the pellet image, and the position is a distance that is within the center or away from the overrun amount after the table is instructed to stop. If set to , it becomes possible to position the tether using the smoke time.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the pellet positioning-machine operation for 11 operations, Figures 2, 3, and 411 are IIi blades of the pellet arrangement; Figure 5M5ria is the conventional index feed theory 91! Sono and Saa are the mask layout diagrams, and the same figure (s) and (b) are the mask layout diagrams for rough positioning and vas deferens positioning in the book 1 of Takahara @56-121271, and Oka l1lCc) is the present invention. Figure 711 is a diagram showing the mask arrangement during high-speed continuous feeding, and Figure 711 is a diagram for comparing the time required by the conventional method and the present invention. Pilgrimage (e)
8 is a timing chart of the conventional method and the method according to the present invention, and FIG. 8 is a block diagram of a processing circuit according to an embodiment of the present invention.・・・・・・Ring, 3・・・・・・
・・・・・・Seat, 4・・・・・・−・・・Center raising bar,
5...Indicates a suction collet. ! ! pJ1 Figure 2 Figure I. Figure 3 vJJ Figure JPls Figure 6 (α) (b) (C) Figure 7 (cL) Cb)

Claims (1)

[Claims] After dicing or scribing the patterned semiconductor wafer pasted on the adhesive sheet, the sheet is pulled and separated, and the semiconductor pellets, which are arranged in a matrix and are supplied, are sequentially peeled off by a suction arm. In order to mount the semiconductor pellet onto a base or lead frame, the semiconductor pellet is photographed two-dimensionally using an optical system.
After converting into a binary image by comparing the output voltage value when the video signal is sampled at a set time interval with the set threshold value, the image is formed on the II system, and then converted into a binary image. The amount of correction necessary for pellet positioning is calculated based on the circumstances, and the tape ktb drive system that holds the cap with the pellets arranged is moved according to the amount of correction, thereby performing positioning. One or more masks are set as a region to limit the counting of white or black bits in the two-dimensional healthy region where the region in the direction in which the beret exists is imaged, and the beret is The feeding form of the table that is lazy in a state where it does not exist continuously is set to high-speed continuous feeding, and the table driving system is determined to continue or stop the high-speed continuous feeding based on the count number of white or stupid bits in the mask. A high-speed pellet positioning system that focuses on control.