JPH05160331A - Die bonding method and lead frame - Google Patents

Abstract

PURPOSE:To provide a method for die bonding of semiconductor chips and a lead frame structure suitable therefor to prevent chips from being damaged when handled during a die bonding operation. CONSTITUTION:A lead frame 3 is provided with through holes 4a and 4b in a chip table 4 therein. A chip 1 is transported with its back face sucked, and received by the ends of receiving pins 13 which have come from below through through holes 4a. The receiving pins 13 then go down to place the chip 1 on the chip table 4. Air is blown from above the chip 1 to compress it against the chip table 4, and further adhesive is injected from below through through holes 4b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding method for adhering a semiconductor chip to a chip table (also called a chip stage, a die stage, etc.) of a lead frame and a lead frame structure suitable for this method.

[0002]

2. Description of the Related Art In the conventional general die bonding method, first, the chips attached to the adhesive tape are pushed up one by one and separated from the adhesive tape, and the separated chips are adsorbed by a collet from the surface side. The chip is conveyed onto a lead frame, and the chip is pressed by the collet and scrubbed on the chip table on which the adhesive of the lead frame is applied to bond the chip. The inner surface of this collet forms a quadrangular pyramid surface, and the peripheral edge of the chip upper surface contacts this surface.

[0003]

However, when the collet sucks the surface side of the chip and carries and presses it, there is a problem that the chip is chipped or the chip surface is damaged.

The present invention solves such a problem and provides a die bonding method in which a chip is not damaged by chip handling, and a lead frame having a structure suitable for this die bonding method. With the goal.

[0005]

According to the present invention, [1] the chip table 4 for mounting the chip 1 is composed of a flat surface portion 4c having a size substantially equal to the planar size of the chip 1 and an inclined surface. Further, it has a guide wall 4d that surrounds the plane portion 4c, and the plane portion 4c supports the receiving pin 13 that supports the chip 1.
A lead frame having through holes 4a and 4b for inserting the chip is provided. [2] When the chip 1 is placed on the chip table 4, the chip 1 is attracted by its back surface and While being conveyed to above the chip table 4, the receiving pin 13 is elevated from below the chip table 4 through the through hole 4a provided in the chip table 4, and the tip of the receiving pin 13 causes the back surface of the chip 1 to move. And then lowering the receiving pin 13 below the chip table 4 to mount the chip 1 on the chip table 4,
Then, the lead frame is vibrated to correct the positional deviation of the chip 1, and when the chip 1 is bonded onto the chip table 4, compressed air is jetted from above the chip 1 placed on the chip table 4. Then, the chip 1 is pressed against the chip table 4, and in this state, an adhesive is injected into the through hole 4b provided in the chip table 4 from the back surface side of the chip table 4. It is achieved by

[0006]

According to the present invention, (1) the chip peeled from the adhesive tape is adsorbed on the back surface of the chip by the transfer arm and transferred onto the chip table of the lead frame, (2) the through hole provided in the chip table. The receiving pin that penetrates through and receives the chip that has been sucked and conveyed on the back surface from the bottom (on the back surface), (3) Drop the receiving pin with the chip mounted on the tip below the chip table (4) The adhesive is injected into the through hole from below while (4) the compressed air is sprayed onto the chip surface from above the chip to press the chip against the chip table in a non-contact manner. That is, throughout this entire process, each part of the device is in contact with the chip only on the back surface thereof, and neither the front surface of the chip nor the peripheral edge thereof is in contact with the solid. Therefore, chip handling does not cause chipping or chipping.

However, according to the chip handling as described above, the displacement of the chip is likely to occur when the chip is delivered. Therefore, if the chip table does not have a sufficient dimension, the chip may protrude from the chip table. The countermeasure is vibration of the guide wall of the chip table and the lead frame. That is, if the guide wall surrounds the four sides of the plane portion that is substantially equal to the chip size, the chip will tilt unless it is placed at the proper position on the chip table. When a slight vibration is applied to the lead frame in this state, the chip moves along the slope of the guide wall in a direction in which the inclination becomes gentle and settles in a non-inclined position, that is, a normal position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a die bonding method and lead frame according to the present invention will be described with reference to FIGS.

FIG. 2 is an explanatory view of the lead frame of the present invention. The lead frame generally comprises a chip table for mounting chips, a large number of lead pieces, an outer frame, etc., but this figure shows an example of the chip table portion of the lead frame based on the present invention, (a) is a top view, (b) is an AA sectional view. The chip table 4 is slightly larger than the plane size of the chip mounted on the upper surface side (+50 to 100 μ).
m) A flat surface portion 4c having a dimension and a guide wall 4d surrounding the flat surface portion 4c on the upper surface side. The height of the guide wall 4d is about the height of the chip to be mounted (for example, 0.25 mm), and each side is inclined (for example, about 45 °) in a direction extending upward from the flat surface portion 4c.

The plane portion 4c has through holes 4a near the four corners thereof.
And has a large number of through holes 4b on the entire surface except the vicinity of the through holes 4a.
have. As an example of mounting a 10 × 12 mm chip, 99 holes are provided in a 9 × 11 mm area with a 1 mm pitch both vertically and horizontally, and the four corners are defined as through holes 4a with a diameter of 0.4 mm.
Ninety-five were used as through holes 4b having a diameter of 0.3 mm.

FIG. 3 is an explanatory view of a die bonding apparatus for carrying out the die bonding method of the present invention. This device comprises a chip peeling unit, a chip transporting unit, a chip bonding unit and the like. The chip peeling unit mounts a large number of chips 1 attached on an adhesive tape 2 and moves stepwise in X and Y directions (not shown), four push-up pins 11, and push-up pins 11 are moved up and down. It includes a pin moving mechanism (not shown) and the like.

The chip transfer section includes a transfer arm 12 and a transfer arm.
The arm 12 is mainly composed of an arm moving mechanism (not shown) for moving in the horizontal direction. A suction hole (not shown) is provided on the upper surface of the tip of the transfer arm 12, and the suction hole communicates with a vacuum source (not shown). The chip bonding part has four receiving pins 13, a pin moving mechanism (not shown) for moving the receiving pins 13 up and down, a vibration generator 14 for applying a minute vibration to the lead frame 3, and a pressure air for pressing the chip 1 against the chip table 4. It comprises an injector 15, an adhesive injector 16 for injecting an adhesive into the through hole 4b of the chip table 4, and the like.

The vibration generator 14 is of a type in which a voltage is applied to a piezoelectric element to obtain vibration. The compressed air injector 15 communicates with a compressed air supply source (not shown) such as nitrogen gas, and has a large number of nozzles on the surface facing the tip table 4. The adhesive injector 16 has a nozzle (injection needle) at a position corresponding to the through hole 4b of the chip table 4, communicates with a compressed air supply source (not shown) such as nitrogen gas, and applies the adhesive by compressed air. Push out from the nozzle.

FIG. 1 is an explanatory view of a die bonding method according to the present invention, in which (a) → (e) is a process order,
Of these, (e) is a partially enlarged cross-sectional view showing a state where an adhesive is injected. First, push up the pin from below the adhesive tape 2.
11 is lifted to push up one of the chips 1 attached on the adhesive tape 2 (peeling from the adhesive tape 2), and the transport arm 12 is moved to face the tip of the chip 1 below the peeled chip 1. (See Figure 1 (a)).

Next, the push-up pin 11 is lowered to drop the chip 1.
Is placed on the transfer arm 12, and at the same time, the transfer arm 12 starts adsorption of the chip 1. Next, the carrier arm 12 is moved to carry the chip 1 above the chip table 4 of the lead frame 3. At this time, the receiving pin 13 is raised to the height of the chip 1 from below the chip table 4 through the through hole 4a (see FIG. 1 (b)).

Next, the adsorption of the chip 1 by the transfer arm 12 is stopped and the chip is retracted rearward, after which the receiving pin 13 is lowered below the chip table 4. As a result, the chip 1 is placed on the flat surface portion 4c of the chip table 4 (FIG. 1 (c)).
reference). Next, the vibration generator 14 gives a minute vibration (for example, an amplitude of 50 μm and a frequency of 500 Hz) to the lead frame 3. As a result, even if the position of the chip 1 is slightly deviated, it moves to the regular position.

Next, the compressed air injector 15 is brought close to directly above the chip 1 to inject compressed air toward the surface of the chip 1. Further, the adhesive injector 16 is moved directly below the chip table 4, and the tip of the nozzle is inserted into the through hole 4b to inject the adhesive (conductive paste) (see FIG. 1 (d)). The result is shown in Fig. 1 (e).
Shown in. After that, the pressure ejector 15 and the adhesive injector 16 are retracted to complete the die bonding.

The present invention is not limited to the above embodiments, but can be implemented with various modifications. For example,
The chip table 4 of the lead frame 3 is provided with no guide wall 4d surrounding the flat portion 4c, and the chip 1 is mounted on the chip table 4
The present invention is effective even when the lead frame 3 is not vibrated after being placed on the top.

[0019]

As described above, according to the present invention,
Since there is no contact with anything other than the backside of the chip during chip handling during die bonding, die bonding can be performed without chipping or chip surface damage, contributing to improved yield in semiconductor device manufacturing. To do.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a die bonding method of the present invention.

FIG. 2 is an explanatory diagram of a lead frame of the present invention.

FIG. 3 is an explanatory diagram of an apparatus for performing the die bonding method of the present invention.

[Explanation of symbols]

 1 chip 2 adhesive tape 3 lead frame 4 chip table 4a, 4b through hole 4c flat surface 4d guide wall 11 push-up pin 12 transfer arm 13 receiving pin 14 vibration generator 15 pneumatic injector 16 adhesive injector

Claims (4)

[Claims] 1. A chip table (4) for mounting a chip (1) comprises a flat part (4c) having a size substantially equal to the plan size of the chip (1), and a flat surface (4c) which is formed by an inclined surface. And a guide wall (4d) which surrounds the flat portion (4c), and the flat portion (4c) supports the chip (1).
A lead frame having through holes (4a, 4b) for inserting (13). 2. When the chip (1) is placed on the chip table (4) of the lead frame (3) according to claim 1, the chip (1) is adsorbed on the back surface of the chip table (4) and the chip table is attached.
(4) The receiving pin (13) is transferred from above and the receiving pin (13) is inserted from below the chip table (4) through the through hole of the chip table (4).
(4a) is pierced and raised so that the tip of the receiving pin (13) supports the back surface of the chip (1), and then the receiving pin (13) is lowered below the chip table (4). The chip (1) with the chip table (4)
A die bonding method characterized by placing on top. 3. The chip (1) is placed on the chip table (4) of the lead frame (3) according to claim 1, and then the lead frame (3) is vibrated to cause the chip (1) to move. The die bonding method according to claim 2, wherein the positional deviation is corrected. 4. When bonding the chip (1) onto the chip table (4) of the lead frame (3) according to claim 1, above the chip (1) placed on the chip table (4). The tip (1) is ejected by injecting compressed air from the tip table.
The adhesive is injected into the through hole (4b) provided in the chip table (4) from the back surface side of the chip table (4) by pressing against the (4). Die bonding method.