JP2619443B2 - How to pick up pellets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method in which a pellet affixed to a surface of a wafer sheet stretched on a wafer support frame such as a wafer ring is transferred to a suction collet disposed above the pellet. And how to pick it up.

[Conventional technology]

Generally, when manufacturing semiconductor elements such as ICs, a wafer is attached to a wafer sheet stretched over a wafer support frame,
The wafer is divided into a plurality of pellets in this state,
The pellets are picked up one by one from a wafer sheet by a suction collet disposed above the pellets, and then transferred and supplied to a lead frame or a substrate.

Then, as a conventional method of picking up the pellet adhered to the wafer sheet by an adsorption collet disposed above, for example, as described in JP-A-57-83041, The pellet attached to the surface of the wafer sheet stretched on the ring,
It is well known that a needle-like body from the back surface of the wafer sheet pushes up the suction collet relatively to the wafer sheet and sucks the collet.

[Problems to be solved by the invention]

In this method, the pellet is lifted up relative to the suction collet with respect to the suction collet by a needle-like body, whereby the pellet is separated from the wafer sheet and, at the same time, is adsorbed to the suction collet. In order to ensure that the pellet is separated from the wafer sheet by the pressing of the body, the needle-like body needs to be formed into a thin and sharp needle with a sharp tip.

However, forming the tip portion of the needle-shaped body into a thin, sharp, sharp needle as described above has a problem in that the end portion formed on the sharp needle has low durability, and moreover, When the pellet is pressed against the adsorption collet with the needle-like body, the sharp needle at the tip breaks through the wafer sheet and comes into direct contact with the pellet. In the case of a pellet in which various integrated circuit layers, light emitting layers, etc. are formed on both sides of the pellet, both sides of which are attached to the wafer sheet, the pellet is damaged by the sharp needle at the tip of the needle-like body. The degree became large, and the yield rate of the product was significantly reduced.

Therefore, Japanese Patent Application Laid-Open No. 57-83038 as a prior art discloses a wafer sheet in a state in which one of a plurality of pellets on the upper surface of a wafer sheet is pushed up with a needle-like body relatively to the wafer sheet. Is proposed to peel the pellet from the wafer sheet by vibrating the pellet in the lateral direction.However, when the pellet is pushed up relative to the wafer sheet by a needle-like body, the pellet is Before the pressure contact with the suction collet disposed above, the wafer sheet vibrates in the horizontal direction, so that the pellets separated from the wafer sheet by the horizontal vibration can be moved in the horizontal direction. It is said that there are many suction mistakes that it is not possible to suck with the suction collet arranged above it There was a problem.

Also, another prior art 56-100433 is one of a plurality of pellets on the upper surface of the wafer sheet, in a state supported by a pedestal having a flat tip on the back side, It has been proposed that the single pellet is separated from the wafer sheet by adsorbing with a vacuum type suction collet and vibrating the suction collet or the wafer sheet in this state.

However, this is one in which the suction pellet is brought into contact with the one pellet in a state where the one pellet is supported on a back surface having a flat front end on the back side, in other words, the one pellet. On the underside of the pellet,
Since the wafer sheet is pressed over a wide area by a receiving table having a flat front end and the pellets are separated from the wafer sheet only by the vibration, a large force is required for the vibration. As a result, elongation deformation occurs in the wafer sheet, and due to this elongation deformation, not only a situation where pellets cannot be correctly moved and supplied to the position of the suction collet or a situation where they cannot be peeled off easily occur, but also the above-mentioned situation occurs. Since a long time is required for peeling, there is a problem that the work efficiency of the pickup is low.

An object of the present invention is to provide a pickup method that solves these problems at once.

[Means for solving the problem]

In order to achieve this object, the method of the present invention comprises the steps of: "making one of a large number of pellets adhered to the front surface of a wafer sheet stretched on a wafer support frame into a needle-like body from the back surface of the wafer sheet. In the pickup method, the suction collet disposed above the pellet is pushed up relatively with respect to the wafer sheet. In the pickup method, the tip of the needle-shaped body is rounded instead of being sharpened. Shape, the one pellet is pushed up relative to the wafer sheet by the needle-shaped body and pressed against the suction collet, and in this pressed state, the wafer support frame is moved to the wafer. The sheet is reciprocated a small distance in a lateral direction parallel or substantially parallel to the surface of the sheet. "

[Functions and Effects of the Invention]

By pressing the pellet adhered to the wafer sheet relatively against the wafer sheet with a needle-shaped body having a rounded shape instead of having a sharpened tip, and pressing against the suction collet, The wafer sheet is separated from the pellet by leaving a portion pressed by the round tip of the needle-like body with respect to the pellet, and other portions are separated from the pellet. As a result, the pellet pressed and contacted with the suction collet by pushing up the needle-like body is in the form of being stuck to the wafer sheet only in a small area in the roundness of the tip of the needle-like body, and the shape of the needle-like body The rounded tip not only ensures that the tip of the needle-shaped body is not deformed, but also ensures that the pellet is scratched or chipped. Can be prevented.

Therefore, in this state, the wafer supporting frame supporting the wafer sheet is reciprocated by a small distance in the horizontal direction parallel to the surface of the wafer sheet, whereby the pellet pressed by the needle-like body in the wafer sheet. Since the tension is alternately applied to the portion where is attached by the reciprocating movement of the wafer support frame in the horizontal direction, and the portion is repeatedly stretched and strained, the portion is pressed and adsorbed by the adsorption collet. The pellets are reliably and easily peeled off from the wafer sheet without moving laterally with respect to the suction collet.

Therefore, according to the present invention, the releasability of peeling the pellet adhered to the wafer sheet from the wafer sheet by pushing up the needle-like body relative to the wafer sheet can be significantly improved. And the occurrence of mistakes in the suction by the suction collet can be reliably reduced, the time required for peeling can be reduced, and the work efficiency of the pickup can be greatly improved.

In addition, the needle-shaped body has high durability, and in the case of a pellet in which various integrated circuits, light-emitting layers, and the like are formed on the surface of the front and back surfaces of the pellet on the side to be attached to the wafer sheet, At the time of pickup, there is also an effect that the pellet can be reliably prevented from being damaged, and thus the yield rate during pickup can be reliably prevented from lowering.

〔Example〕

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

In the figure, reference numeral 1 denotes an XY table, and the XY table 1 has an X direction moving mechanism 2 for moving the XY table 1 in the X direction.
And a Y-direction moving mechanism 3 that moves in the Y direction perpendicular to the X direction. A wafer sheet 5 is stretched on a wafer support frame 4 mounted on the XY table 1. A large number of pellets 6 formed by cracking a wafer are stuck on the upper surface of the wafer.

Reference numeral 7 denotes a vacuum type suction collet which is disposed above the wafer sheet 5 so as to move up and down.
Indicates needle-like bodies disposed at the lower portion of the wafer sheet 5 and directly below the suction collet 5, and the needle-like bodies 8 are rounded instead of having a sharpened tip. A hollow sleeve 9 is fitted to the needle-shaped body 8 so as to be movable up and down.
Is configured to move up and down by an air cylinder or the like (not shown).

Then, by moving the XY table 1 in the X and Y directions, one pellet 6 on the upper surface of the wafer sheet 5 is positioned directly below the suction collet 7 (FIG. 3). It descends until it contacts the pellet 6 (FIG. 4).

Next, as shown in FIG. 5, the sleeve 9 is lowered in a state where the wafer sheet 5 is vacuum-sucked, so that the pellet 6 is pushed up by the needle-shaped body 8 inside thereof relative to the wafer sheet 5. Is held in a state of being pressed against the suction collet 7.

As a result, the wafer sheet 5 leaves the portion pressed by the rounded tip of the needle-shaped body 8 against the pellet 6, and the other portions are separated from the pellet 6. The pellet 6 pressed and contacted with the suction collet 5 by being pushed up is stuck to the wafer sheet 5 only in a small area in the rounded tip of the needle-shaped body 8.

In this state, by operating the X-direction moving mechanism 2 or the Y-direction moving mechanism 3 in the XY table 1, the wafer supporting frame 4 is moved a small distance (for example, in the horizontal direction parallel or substantially parallel to the surface of the wafer sheet 5). , 10 to 60 microns).

Then, the tension is alternately applied to the portion of the wafer sheet 5 where the pellet 6 pressed and contacted with the suction collet 6 by the needle 8 is adhered by the reciprocating movement of the wafer support frame 4 in the lateral direction. Then, since the extension strain is repeatedly generated in the portion, even if the tip portion of the needle-shaped body 8 is formed in a rounded needle shape as shown in FIG. The sucked pellet 8 is reliably and easily peeled off from the wafer sheet 5 without moving laterally relative to the suction collet 6.

In the embodiment, the sleeve 9 fitted on the needle-shaped body 8 is used.
, The pellet 6 on the upper surface of the wafer sheet 5 is pushed up relative to the wafer sheet 5 and pressed against the suction collet 7. However, the present invention is not limited to this. Needless to say, the present invention can also be applied to a case where the needle 6 is moved upward to push the pellet 6 on the upper surface of the wafer sheet 5 relatively up against the wafer sheet 5 so as to press against the suction collet 7. No.

When the wafer support frame 4 is reciprocated in the horizontal direction, it is more effective if the wafer support frame 4 is reciprocated a small distance in both the X direction and the Y direction.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional front view, FIG. 2 is a plan view, FIG. 3 is an enlarged view of a main part of FIG. 1, and FIG. 4 and FIG. FIG. DESCRIPTION OF SYMBOLS 1 ... XY table, 2 ... X direction moving mechanism, 3 ... Y direction moving mechanism, 4 ... Wafer support frame, 5 ... Wafer sheet, 6 ... Pellets, 7 ... Suction collet, 8 ... Needle Shape, 9 ... Sleeve.

Claims (1)

(57) [Claims] 1. A method in which one of a plurality of pellets stuck to the front surface of a wafer sheet stretched on a wafer support frame is placed above the pellets by a needle-like body from the back surface of the wafer sheet. In the pickup method, the tip of the needle-shaped body is rounded instead of being pointed, and the one pellet is formed. The needle-like body pushes up the wafer sheet relatively to the suction collet and presses against the suction collet. In the state of the press contact, the wafer support frame is parallel or substantially parallel to the surface of the wafer sheet. A pellet reciprocatingly moved by a small distance in a lateral direction.