JPH09246295A - Die bonding apparatus and die bonding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide die bonding apparatus and die bonding method which enable a collet to reliably pick up a chip by thrusting the chip by using a needle in consideration of the holding force with which an adhesive sheet holds the chip. SOLUTION: A collet 23 moves downward onto a chip 4 on an adhesive sheet 3, and a needle 9 moves upward onto the lower surface of the adhesive sheet 3. If a predetermined period has elapsed, the needle 9 and the collet 23 move upward at the same speed, in synchronization with each other, so that the collet 23 picks up the chip 4 from the adhesive sheet 3. The holding force of the adhesive sheet 3 with which the adhesive sheet 3 holds the chip 4 is determined by a chip size and an adhesion coefficient. Accordingly, correlative relation is obtained in advance among the speed of the synchronized upward movement of the needle 9 and the collet 23, the height of the synchronized upward movement, and the parameter of the holding force. The needle 9 and the collet 23 are moved upward in synchronization with each other, based on the correlative relation, to pick up the chip 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding apparatus and a die bonding method for picking up a chip attached to the upper surface of an adhesive sheet with a collet and transferring and mounting it on a substrate.

[0002]

2. Description of the Related Art A die-bonding device is a chip attached to the upper surface of an adhesive sheet, which is picked up by vacuum suction with a collet while pushing it up with a needle from below and moving the collet upwards such as a lead frame or a printed circuit board. Therefore, the collet is moved up and down to mount the chip on the substrate.

[0003]

Since the chip is attached to the adhesive sheet by a bond, it is difficult to pick up the collet by itself. Therefore, when the collet picks up the chip, the tip of the collet is pushed up from below and peeled from the adhesive sheet to assist the collet pickup operation.

The holding force with which the adhesive sheet sticks the chip is
It is a function of the bond strength of the bond and the chip size (chip area). That is, the larger the adhesive strength and the chip size,
The adhesive sheet has a large holding force for holding the chip, and the chip is not easily peeled off from the adhesive sheet even when it is pushed up from below by a needle. However, conventional die bonding equipment
Since the tip was pushed up from below by raising the needle without paying attention to the magnitude of this holding force, insufficient peeling of the tip due to insufficient push-up force, and tip protrusion due to excessive push-up force are likely to occur. As a result, the collet has a problem that it is easy to pick up a chip.

Therefore, the present invention provides a die bonding apparatus and a die bonding method by which a collet can pick up a chip surely without a pick-up error by pushing up the chip with a needle in consideration of the strength of the chip holding force of the adhesive sheet. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a needle pushes up a chip on a pressure-sensitive adhesive sheet from below, a first motor that causes the needle to move up and down, and a chip pushed up by the needle to pick up a substrate. A die bonding apparatus comprising: a collet to be transferred to and mounted on a substrate; a second motor for vertically moving the collet; and a moving table for moving the collet between an adhesive sheet and a substrate. A control system for the motor and the second motor includes a first motor drive circuit that drives the first motor, a second motor drive circuit that drives the second motor, the needle and the collet. A synchronous rising height table for registering the synchronous rising height of the needle and the collet when picking up a chip while rising synchronously. And / or the synchronous rising speed table for registering the synchronous rising speed, and the first motor driving circuit and the second motor driving circuit based on the data registered in the synchronous rising height table and / or the synchronous rising speed table. And a control unit for controlling.

Further, the second vertical movement means is driven to lower the collet toward the chip attached to the upper surface of the adhesive sheet, and the first vertical movement means is driven to move the needle toward the adhesive sheet. The chip is lifted and pinched from above and below by the collet and needle, and in this pinched state, the collet and needle are synchronously lifted at the same speed to peel off the chip from the adhesive sheet and pick up with the collet, then the collet above the substrate. Is a die bonding method of mounting the chip on the substrate by moving to, in accordance with the holding force of the chip of the adhesive sheet, at least the synchronous rising speed or synchronous rising height when the collet and the needle are synchronously rising. One data is set in advance, and based on this data, the collet and needle are raised synchronously and the tip is picked up. It was to be flops.

[0008]

According to the present invention, by adjusting the ascending speed and the ascending height of the collet and the needle during the synchronous ascending according to the chip holding force of the adhesive sheet, the chip can be removed from the adhesive sheet by the needle. It can be reliably peeled off and picked up by the collet.

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 same chip, FIG. 3 is an explanatory diagram of a pickup operation of the same chip, and FIG. FIG. 5 is an adhesive coefficient table diagram, FIG. 5 is a synchronous rising speed table diagram, FIG. 6 is a synchronous rising height table diagram, and FIG. 7 is a flowchart for obtaining the same operation pattern.

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 attached by a bond. A push-up unit 6 for the chip 4 is provided below the wafer 1.
The push-up unit 6 is configured by arranging a pepper pot 8 on the upper surface of a case 7 and accommodating a needle holder 10 holding a needle 9 inside the pepper pot 8.
A first motor 11 is provided on the side of the case 7. The first motor 11 rotates the cam 12. A roller 13 that contacts 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 the needle 9 is caused to perform a predetermined vertical movement by rotating the cam 12 forward and backward. That is, the first motor 11, the cam 12, and the roller 13 are first vertical movement means for causing the needle 9 to perform vertical movement.

A moving table 20 is provided above the wafer 1. A head portion 21 is attached to the moving table 20. The head portion 21 holds a second motor 22, and the second motor 22 holds a collet 23. That is, the second motor 22 is the collet 2
3 is a second vertical movement means for causing the vertical movement of the robot 3. The second motor 22 is a linear motor. Therefore, when the second motor 22 is driven, the collet 23 moves up and down. Further, by driving the moving table 20, the head part 21 moves horizontally between the wafer 1 and the substrate 24. Reference numeral 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 through the first operation pattern storage unit 41, the first pulse generation circuit 42, and the first motor drive circuit 43. The control unit 40 also includes a second operation pattern storage unit 44, a second pulse generation circuit 45,
The drive of the second motor 22 is controlled through the second motor drive circuit 46.

The first motion pattern storage unit 41 and the second motion pattern storage unit 44 store motion patterns for causing the needle 9 and the collet 23 to perform a predetermined vertical motion, respectively. Further, the first pulse generation circuit 42 and the second pulse generation circuit 45 are configured to operate the first motor 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 are generated. A synchronous rising speed table 51 and a synchronous rising height table 52 are connected to the control unit 40. Reference numeral 53 is an input unit for inputting data such as chip size and adhesion coefficient (described later).

FIG. 4 shows an example of the type of adhesive sheet 3 and its adhesive coefficient (adhesive strength). As shown in the figure, the adhesive coefficient of the adhesive sheet 3 varies depending on the type of UV sheet, weakly viscous sheet A, or the like. This adhesion coefficient is input by the input unit 53.

FIG. 5 is a synchronous rising speed table in which the vertical axis indicates the synchronous rising speed V of the needle 9 and the collet 23 (see FIG. 2).
In (d), the rising speed between d and e), and the horizontal axis is the parameter m of the holding force of the chip 4 of the adhesive sheet 3. The holding force parameter m is the product of the chip size (chip area) attached to the adhesive sheet 3 and the adhesive coefficient shown in FIG. In FIG. 5, as the parameter m increases, the chip 4
Indicates that the chip 4 is strongly adhered to the adhesive sheet 3, so that it is necessary to reduce the synchronous rising speed and slowly push up the chip 4 to pick up. The characteristic line P1 in FIG. 5 is determined by experiments and experience.

FIG. 6 is a synchronous rising height table, in which the vertical axis is the rising height H of the needle 9 (the height between i and j in FIG. 2), and the horizontal axis is the parameter m similar to FIG. . FIG.
Is the higher height H of the needle 9 as the parameter m is larger.
Indicates that the chip 4 needs to be pushed up by a large amount. This characteristic line P2 is also determined by experiments and experience.

The die bonding apparatus is constructed as described above, and its operation will be described below. First, with reference to the flowchart of FIG. 7, a method of obtaining the operation patterns stored in the first operation pattern storage unit 41 and the second operation pattern storage unit 44 shown in FIG. 1 will be described. First, in step 1 of FIG. 7, the chip size (chip area) and the adhesion coefficient are input from the input unit 53. Next, in step 2, the product m of the area of the chip and the adhesion coefficient (parameter of the chip holding force) is obtained. This product (parameter) m is
The value is calculated by the control unit 40. Next, the synchronous rising speed V corresponding to the parameter m is obtained from the synchronous rising speed table shown in FIG. 5 (step 3). Similarly, from the synchronous rising height table shown in FIG.
The synchronous rising height H corresponding to is calculated (step 4). Based on the results obtained in step 3 and step 4, the first operation pattern is obtained and the first operation pattern storage unit 4 is obtained.
It is stored in 1 (step 5). Further, the second operation pattern is obtained and stored in the second operation pattern storage unit 44 (step 6). The second operation pattern is to match the timing of point d with the timing of point i in FIG.
It can be easily obtained by matching the gradient and time of i with the gradient and time of i-k or i-j.

After the first operation pattern and the second operation pattern are obtained as described above, the mounting work for mounting the chips 4 of the wafer 1 on the substrate 24 is started in accordance with the operation patterns. The mounting work will be described below.

First, as shown in FIG. 1, the collet 23 is stopped above the desired chip 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 a in FIG.
From the point to the point b, it descends at a high speed and from the point b at a low speed, and the collet 23 reaches the upper surface of the chip 4 at the point c.
The reason why the speed is changed to the low speed at the point b is to prevent the collet 23 from strongly landing on the chip 4 at a high speed and destroying the chip 4. 3A shows a state in which the collet 23 is lowered to the point b, and FIG. 3B shows a state in which the collet 23 is lowered to the point c.

On the other hand, the needle 9 starts rising at point g,
At the point h, the lower surface of the adhesive sheet 3 is reached. FIG. 3C shows the state at this time. That is, the needle 9 is
After the collet 23 lands on the upper surface of the chip 4, it reaches the lower surface of the adhesive sheet 3 with a slight delay. In step 3,
Confirm that the collet 23 and the needle 9 have stopped their descending and ascending operations. 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 confirming means for confirming the stop of the descending operation of the collet 23 and the ascending operation of the needle 9. If you make this confirmation,
Wait for the stabilization time t to elapse. This stabilization time t is the time required for the collet 23 to firmly vacuum-adsorb the chip 4, and FIG. 3C shows the needle 9 and the collet 23 during this stabilization time t.

When the stabilization time t has elapsed, the first motor 11 and the second motor 22 are simultaneously driven to drive the needle 9
And the collet 23 are synchronously raised, and the chip 4 is peeled off from the adhesive sheet 3 and picked up. As a result, the timing at which the collet 23 starts to rise (point d) and the timing at which the needle 9 starts to rise (point i) are reliably matched, and the tip 4 is sandwiched between the collet 23 and the needle 9 from above and below for pickup. can do. FIG.
(D) shows the operation at this time, as shown in the figure, the needle 9 pierces the adhesive sheet 3 and pushes up the chip 4 while peeling it off from the adhesive sheet 3, and the collet 23 raises the chip 4 pushed up. To pick up.

In FIG. 2, after the point d and after the point i, the solid line shows the case where the chip size is large (that is, the holding force of the adhesive sheet 3 is large), and the broken line shows the case where the chip size is small (that is, the case). (When the holding power is small). First, the case where the chip size is large will be described with reference to the solid line. In this case, the needle 9 is
At point j, when it reaches point j, it stops ascending, then starts descending at point k, and descends toward point l, which is the height of the start position. On the other hand, the collet 23 ascends at the same speed as the needle 9 from point d to point e, but shifts from point e to high speed and stops rising at point f. FIG. 3E shows the state in the middle of the process. With the above, the pickup operation of the chip 4 by the collet 23 is completed. Next moving table 2
0 starts driving, and the collet 23 moves above the substrate 24, where it moves up and down to transfer and mount the chip 4 to a predetermined position on the substrate 24, and then returns to the start position. As described above, the operation of one cycle is completed.

Next, the case where the chip size is small will be described with reference to the broken line in FIG. In this case, a-d and g-
Up to i, it is the same as when the chip size is large. If the tip size is small, the needle 9 between ij '
However, the rising speed is faster than that when the chip size is large. This is because the adhesive force of the adhesive sheet 3 is weak when the chip size is small, and therefore the chip 4 can be peeled off at a high speed. Also, the rising height is lower than when the chip size is large. This is because if the rising height is increased, the tip 4 may be excessively pushed up by the needle 9 and jump out. After the needle 9 pushes up the tip 4 as described above,
It descends to the l'point which is the height of the start position. On the other hand, the collet 23 ascends synchronously at the same speed as the needle 9 during d-e ', increases the ascending speed from e', completes the pickup at f ', and transfers and mounts it on the substrate 24.

As described above, when the tip size is large, the needle 9 is raised at a low speed and the collet 2
Pick up chip 4 at 3. If the chip size is small, the needle 9 is moved up at a high speed to pick up the chip with the collet 23. Accordingly, when the chip size is small, the takt time can be shortened by ta (difference between f point and f ′ point) as compared with the case where the chip size is large. Therefore, according to this method, the needle 9 and the collet 23 can be optimally operated according to the chip size, and in particular, the smaller the chip size, the shorter the tact time and the higher speed mounting. The present invention is not limited to the above embodiment, and the occurrence of pickup error can be reduced by using only one of the characteristic lines P1 and P2 shown in FIGS. 5 and 6, for example.

[0025]

According to the present invention, by adjusting the ascending speed and the ascending height when the collet and the needle are synchronously ascended according to the holding force of the chip of the adhesive sheet, the needle ensures the chip from the adhesive sheet. It can be peeled off and picked up with a collet. Therefore, a chip pick-up error can be eliminated and the chip can be surely mounted on the substrate. Further, the needle and the collet are optimally operated according to the chip size, and in particular, the smaller the chip size, the shorter the tact time and the higher the mounting speed.

[Brief description of 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 pickup operation of a chip according to an embodiment of the present invention.

FIG. 4 is a diagram showing an adhesive coefficient table of an adhesive sheet according to an embodiment of the present invention.

FIG. 5 is a table of a synchronous rising speed table according to an embodiment of the present invention.

FIG. 6 is a table of a synchronous rising height table according to an embodiment of the present invention.

FIG. 7 is a flowchart for obtaining an operation pattern according to an embodiment of the present invention.

[Explanation of symbols]

 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 Section 41 First Operation Pattern Storage Section 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)

[Claims] 1. A needle for pushing up a chip on an adhesive sheet from below, and a needle for vertically moving the needle.
Motor, a collet for picking up a chip pushed up by this needle and transferring and mounting it on the substrate, a second motor for vertically moving this collet, and a moving table for moving this collet between the adhesive sheet and the substrate. A die bonding apparatus comprising: a first motor and a second motor, wherein a control system for the first motor and the second motor drives a first motor drive circuit that drives the first motor; and a second motor. A second motor drive circuit, a synchronous rising height table and / or a synchronous rising speed for registering a synchronous rising height of the needle and the collet when picking up a chip while the needle and the collet are synchronously rising. To register the synchronous rising speed table and the data registered in this synchronous rising height table and / or the synchronous rising speed table. A die bonding apparatus, comprising: a controller that controls the first motor drive circuit and the second motor drive circuit based on a controller. 2. A second vertical movement unit is driven to lower the collet toward the chip attached to the upper surface of the adhesive sheet,
Further, the first vertical movement means is driven to raise the needle toward the adhesive sheet, and the tip is sandwiched between the collet and the needle from above and below, and the collet and the needle are synchronously elevated at the same speed in the sandwiched state. Is a die-bonding method of peeling from the adhesive sheet and picking up with a collet, then moving the collet to the upper side of the substrate to mount the chip on the substrate, depending on the holding force of the chip of the adhesive sheet, a collet and a needle. Of at least one of the synchronous ascending speed and the synchronous ascending height for synchronously ascending, and based on this data, the collet and the needle are synchronously ascended to pick up the chip. Bonding method.