JP3149772B2 - How to pick up chips - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip pickup method for picking up a chip attached to an adhesive sheet with a collet.

[0002]

2. Description of the Related Art In a die bonding apparatus, a chip affixed to the upper surface of an adhesive sheet is picked up by being sucked up by a collet while being pushed up from below by a needle, and transferred and mounted on a substrate such as a lead frame or a printed circuit board. You. Hereinafter, a method of picking up a chip in a conventional die bonding apparatus will be described.

FIG. 5 is an explanatory diagram of a conventional chip pickup method. The horizontal axis represents time, the vertical axis represents height, the upper folding curve A represents the up and down movement of the collet, and the lower folding curve B represents the up and down movement of the needle. The horizontal line C indicates the height of the pressure-sensitive adhesive sheet having the chip attached to the upper surface.

Next, the operation will be described. In the figure, point a is the start position of the collet, and g is the start position of the needle. First, when the collet descends from point a to point b at a high speed, descends to point b and approaches the upper surface of the chip, the collet lowers its speed, descends further, lands on the upper surface of the chip, and stops descending. Point c is the upper surface of the chip (the stop point of the collet lowering operation). When the collet arrives at the point c, the collet vacuum-adsorbs the chip until the point d, while still landing on the upper surface of the chip.

On the other hand, the needle starts rising at point g, and h
At this point, the chip reaches the lower surface of the adhesive sheet to which the chip has been attached, and stops the ascent operation. Then, the needle continues to stop until the point i corresponding to the point d at which the collet surely vacuum-adsorbs the chip and starts rising. The time t from the point h to the point i is referred to as a stable time. Then, the collet starts rising at the point d, the needle starts rising at the point i, and the chip is peeled off from the adhesive sheet and picked up by the collet. The ascending speed from the point i to the point j is the same, whereby the chip is picked up by the collet while pushing up the chip with the needle.

When the collet reaches point e, the collet increases its ascending speed and rises at a high speed to point f, which is the pickup end point. The needle stops from point j to point k and then starts descending at point k. Then, it descends to the point 1 which is the start position. The collet that has moved up to the point f and completed the pickup operation moves to above the substrate, and transfers and mounts the chip at a predetermined position on the substrate.

As described above, the collet and the needle pick up the chip while moving up and down on the trajectories indicated by the folding curves A and B. A cam that rotates by being driven by a motor (this cam has a cam curved surface on which bent curves A and B can be obtained) is used as a means for vertically moving the collet and the needle. By doing so, the up and down operation of one cycle shown in FIG. 5 was performed.

[0008]

In order to reliably pick up a chip with a collet, the point d where the collet starts rising and the point i where the needle starts rising must coincide. The time lag Δ between the points d and i
With t, the collet cannot reliably pick up the chip. That is, if the point i is earlier than the point d, the chip is pushed up by the needle while being pressed by the collet, and the chip is broken. If the point d is earlier than the point i, the collet tends to pick up the chip because the collet attempts to pick up the chip without pushing up the chip with the needle.

As described above, in order to reliably pick up a chip, it is necessary to match the points d and i.
Therefore, conventionally, the rotation start point (point of 0 °) of the collet lifting / lowering cam for starting the lowering of the collet at the point a,
The rotation control of the two cams is performed so that the timing of the rotation start point (point at 0 °) of the cam for raising and lowering the needle at the point g is started.

However, it is practically difficult to control the rotation of the two cams so that the rotation start point of the collet elevating cam and the needle elevating cam completely coincide with each other. And the i point tends to cause a time lag Δt, which causes the above-described pickup error to occur easily.

Accordingly, an object of the present invention is to provide a method of picking up a chip which can reliably pick up a chip attached to an adhesive sheet by using a collet without a pick-up error.

[0012]

For this purpose, the present invention drives a second up / down moving means toward a chip attached to the surface of an adhesive sheet to lower a collet. First
A step of driving the up and down moving means to raise the needle,
A step of confirming that the collet has stopped descending and that the needle has stopped ascending by the confirming means, respectively, and after confirming that both the collet descending operation and the needle ascending operation have stopped in the above step, a predetermined After the elapse of the stabilization time, the first vertical movement means and the second
A method of picking up the chip was constituted by the steps of starting the ascending of the collet and the needle simultaneously at the same speed by driving the vertical movement means, peeling the chip from the adhesive sheet, and picking up the chip with the collet.

[0013]

According to the structure of the present invention, after the collet reaches the upper surface of the chip, a predetermined stabilization time elapses and the needle starts to rise, and the needle rises to start pushing up the chip. It is possible to pick up the chip by the collet with the points to be surely matched.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a die bonding apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a pickup method of the chip, FIG. 3 is an explanatory diagram of a pickup operation of the chip, and FIG. It is a flowchart of an operation.

First, the overall structure of the die bonding apparatus will be described with reference to FIG. Reference numeral 1 denotes a wafer, and a chip 4 is provided on the surface of the adhesive sheet 3 attached to the ring holder 2.
Are bonded by bond. A push-up unit 6 for chips 4 is provided below the wafer 1.
The push-up unit 6 is configured such that a pepper pot 8 is erected on the upper surface of a case 7 and a needle holder 10 holding a needle 9 is accommodated inside the pepper pot 8.
A first motor 11 is provided on a side of the case 7. The first motor 11 rotates the cam 12. A roller 13 that abuts on the cam 12 is provided below the needle holder 10.
The roller 13 is pressed against the peripheral surface of the cam 12 by the spring force of the spring 14. The cam 12 is a constant velocity cam, and causes the needle 9 to perform a predetermined up-down operation by rotating the cam 12 forward and reverse. That is, the first motor 11, the cam 12, and the roller 13 are first vertical moving means for causing the needle 9 to perform a vertical operation.

A moving table 20 is provided above the wafer 1. The head part 21 is mounted on the moving table 20. The head unit 21 holds a second motor 22, and the second motor 22 holds a collet 23. That is, the second motor 22 is
3 is a second vertical movement means for causing the vertical movement 3 to perform vertical movement. The second motor 22 is a linear motor. Therefore, when the second motor 22 is driven, the collet 23 moves up and down. When the moving table 20 is driven,
The head unit 21 moves between the wafer 1 and the substrate 24 in the horizontal direction. 25 is a table for positioning the substrate 24.

Next, the control system will be described. A control unit 40 controls the driving of the first motor 11 via a first operation pattern storage unit 41, a first pulse generation circuit 42, and a first motor drive circuit 43. Further, the control unit 40 includes a second operation pattern storage unit 44, a second pulse generation circuit 45,
The drive of the second motor 22 is controlled via the second motor drive circuit 46.

The first operation pattern storage section 41 and the second operation pattern storage section 44 store operation patterns for causing the needle 9 and the collet 23 to perform predetermined up and down operations, respectively. The first pulse generation circuit 42 and the second pulse generation circuit 45 perform the first motor generation based on the operation patterns stored in the first operation pattern storage unit 41 and the second operation pattern storage unit 44, respectively. 11 and a pulse for driving the second motor 22 is generated. The first pulse generation circuit 42, the first motor drive circuit 43, the second
Of the pulse generation circuit 45 and the second motor drive circuit 46
Each driving condition is fed back to the control unit 40,
The control unit 40 controls the first operation pattern storage unit 41 and the second operation pattern storage unit 44 based on the feedback signal.
Control.

This die bonding apparatus is configured as described above. Next, the overall operation will be described with reference to FIGS. First, as shown in FIG. 1, the collet 23 is stopped above desired chips 4 on the wafer 1. Next, the second motor 22 is driven to lower the collet 23 toward the chip 4. In this case, the collet 23 is shown in FIG.
The collet 23 descends at a high speed from the point to the point b, descends at a low speed from the point b, and reaches the upper surface of the chip 4 at the point c (step 1 in FIG. 4). The reason for shifting to the low speed at the point b is to prevent the collet 23 from landing on the chip 4 at a high speed and destroying the chip 4. FIG. 3 (a)
3 shows a state where the collet 23 has been lowered to the point b, and FIG. 3 (b) shows a state where the collet 23 has been lowered to the point c.

On the other hand, the needle 9 starts rising at the point g,
It reaches the lower surface of the adhesive sheet 3 at the point h (step 2 in FIG. 4). FIG. 3C shows the state at this time. That is, the needle 9 reaches the lower surface of the adhesive sheet 3 slightly after the collet 23 lands on the upper surface of the chip 4. In step 3, it is confirmed that the collet 23 and the needle 9 have stopped the lowering operation and the raising operation. This confirmation is performed by the control unit 40 based on feedback signals from the first motor drive circuit 43 and the second motor drive circuit 46. That is, the control unit 40 is a confirmation unit for confirming that the lowering operation of the collet 23 and the raising operation of the needle 9 are stopped. After this confirmation, it waits for the stabilization time t to elapse (step 4). This stabilization time t is determined by the collet 23
Is the time required for firmly adsorbing the tip 4 under vacuum, and FIG. 3 (c) shows the needle 9 and the collet 23 during this stabilization time t.

After the stabilization time t has elapsed, the first motor 11 and the second motor 22 are simultaneously driven to
And the collet 23 are raised synchronously, and the chip 4 is peeled off from the adhesive sheet 3 and picked up (step 5). Thereby, the timing (d) at which the collet 23 starts to rise
And the timing (i) at which the needle 9 starts to rise.
2), and the chip 4 can be picked up between the collet 23 and the needle 9 from above and below. FIG. 3D shows the operation at this time. As shown, the needle 9 breaks through the adhesive sheet 3 and pushes up the chip 4 to peel off the adhesive sheet 3, and the collet 23 raises the pushed up chip 4. While picking up.

Next, when the needle 9 reaches the point j in FIG. 2, the needle 9 stops rising, starts to descend at the point k, and moves downward toward the point l which is the height of the start position. On the other hand, the collet 23 shifts from the point e to a high speed and stops rising at the point f. FIG. 3E shows a state in the middle. Thus, the pickup operation of the chip 4 by the collet 23 is completed. Next, the moving table 20 starts to be driven, and the collet 23 moves above the substrate 24. The collet 23 moves up and down to transfer the chip 4 to a predetermined position on the substrate 24, and then returns to the start position. Thus, the operation of one cycle is completed. Hereinafter, by repeating the same operation,
The chips 4 of the wafer 1 are mounted on the substrate 24 one after another.

[0023]

According to the present invention, the collet and the needle are simultaneously started to rise at the same speed after a predetermined stabilization time has elapsed after confirming that both the collet lowering operation and the needle raising operation have stopped. since so as to pick up the peeled collet chips from the adhesive sheet, by Rukoto reliably to match the point where the needle and the collet starts to rise, chip by the collet and needle
Crowded scissors from the top and bottom can be reliably pick up the chip.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a die bonding apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a chip pickup method according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a chip pickup operation according to an embodiment of the present invention.

FIG. 4 is a flowchart of a chip pickup operation according to an embodiment of the present invention.

FIG. 5 is an explanatory view of a conventional chip pickup method.

[Explanation of symbols]

 Reference Signs List 1 wafer 3 adhesive sheet 4 chip 6 push-up unit 9 needle 11 first motor 20 moving table 22 second motor 23 collet 40 control unit 41 first operation pattern storage unit 42 first pulse generation circuit 43 first motor Drive circuit 44 Second operation pattern storage unit 45 Second pulse generation circuit 46 Second motor drive circuit

Claims (2)

(57) [Claims] A step of driving a second vertically moving means to lower a collet toward a chip stuck on a surface of an adhesive sheet and driving a first vertically moving means to raise a needle; A step of confirming that the collet has stopped descending operation and that the needle has stopped ascending operation by confirming means, respectively, and after confirming that both the collet descending operation and the needle ascending operation have stopped in the above step, After a predetermined stabilization time has elapsed, the first vertical
And starting the collet and the needle simultaneously at the same speed by driving the step and the second vertically moving means to separate the chip from the adhesive sheet and picking up the chip by the collet. . 2. The apparatus according to claim 1, wherein said first vertically moving means comprises a constant velocity cam and said constant velocity cam.
It is characterized by comprising a motor for rotating a constant velocity cam
The chip pickup method according to claim 1.