JPH1126518A - Thermal bonding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adhere a plurality of semiconductor chips to a flexible film at the same time, without generating air bubbles in a thermal bonding machine under pressure adhering semiconductor chips to a flexible film. SOLUTION: A flexible film 22 is sandwiched and held between a pressure head 1, having a pressure chamber 3 and a stage 2 having a deaerating chamber 4. Then the pressure chamber 3 and deaerating chamber 4 are separated by a partition, and the air between the semiconductor chip 21 to be adhered to the flexible film 22 in the deaerating chamber 4 is vacuum exhausted, while the flexible film 22 and the semiconductor chip 21 are being heated. Then a high pressure gas is introduced to a pressure chamber 3 and the flexible film 22 is adhered by uniformly pressing it to the semiconductor chip 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermocompression bonding apparatus for attaching a semiconductor chip to a flexible film on which a wiring pattern to be connected to a terminal portion of the semiconductor chip is formed.

[0002]

2. Description of the Related Art FIG. 3 is a view showing the structure of an example of a conventional thermocompression bonding apparatus. Conventionally, a thermocompression bonding apparatus for attaching a semiconductor chip to this flexible film is, for example, shown in FIG.
As shown in the figure, it is lowered by the screw feed mechanism, and the stage 1
And a pressure head 16 for pressing the flexible film against the semiconductor chip placed on the substrate 7 and held by the suction force of the suction port 16a.

In this thermocompression bonding apparatus, a stage 17 and a pressure head 16 are mounted on heater blocks 18a and 18b in order to maintain a high temperature state. Then, the flexible film 22 and the semiconductor chip 21
Was heated to melt the resin adhesive layer formed on the surface of the flexible film, and pressed and bonded the flexible film 22 to the semiconductor chip. The pressing force of the pressure head 16 was adjusted in advance by the load meter 19. Further, the level adjusters 20a and 20b are adjusted so that the surface of the pressure head 16 and the surface of the stage 17 are parallel so that the surface of the semiconductor chip 21 is uniformly pressed.

[0004]

In the thermocompression bonding of a flexible film to a semiconductor chip by the above-described conventional thermocompression bonding apparatus, the parallelism adjustment of a pressure head and a stage having high flatness is performed by thermocompression bonding. Also, as shown in FIG. 4, the air existing at the interface between the resin adhesive layer 25 of the flexible film having the film base 24 and the semiconductor chip 21 and the gas of the resin adhesive layer 25 generated by heating cannot be sufficiently removed and remain as it is. Air bubbles 2
It often remains as 3. There has been a problem that the air bubbles 23 expand during the operation with an increase in the ambient temperature and the adhesive surface is peeled off, resulting in a quality defect. In particular, it is likely to occur in places where pockets of gas or air are present, such as steps of the wiring 26.

In addition, even if a plurality of semiconductor chips are mounted on a stage in order to improve the productivity, the thickness of the semiconductor chips varies, and the thin semiconductor chips are not bonded to the flexible film. Further, even with a single semiconductor chip, the parallelism between the pressure head and the stage must be precisely adjusted, and this adjustment operation requires skill and consumes a great deal of time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a thermocompression bonding apparatus capable of simultaneously attaching a plurality of semiconductor chips to a flexible film without generating bubbles.

[0007]

A feature of the present invention is that a plurality of semiconductor chips connected to the wiring pattern are formed on a flexible film on which a wiring pattern is formed and a thermal adhesive resin layer is formed. In a thermocompression bonding device for bonding via an adhesive resin layer, a first portion having a peripheral portion protruding is provided.
A stage on which the flexible film is mounted together with the semiconductor chip and in which a first heater is built, and a peripheral portion of the flexible film mounted on the stage is formed by the first frame. A second frame-shaped member formed in the periphery in cooperation with the second member and a pressurizing head having a second heater therein, the flexible film mounted on the stage, and the pressurizing head A gas supply device for supplying a high-pressure gas to the space portion, a vacuum exhaust device for evacuating a space portion between the flexible film mounted on the stage and the semiconductor chip, and a device for sandwiching the flexible film. And a pressing means for moving the pressure head and the stage. Further, it is preferable that a recess is formed in the stage so that a surface thereof protrudes by a predetermined height and the semiconductor chip enters. further,
If necessary, a film-like member of the same quality as the flexible film may be interposed between the pressure head and the flexible film. In order to more effectively heat the adhesive member such as the flexible film or the semiconductor chip, it is desirable to provide a heating means for heating the high-pressure gas.

[0008]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a thermocompression bonding apparatus according to an embodiment of the present invention. This thermocompression bonding apparatus is shown in FIG.
As shown in FIG. 5, a heater 12b for mounting the semiconductor chip 21 covered by the flexible film 22 and heating the semiconductor chip 21 is built in, and a space between the periphery of the semiconductor chip 21 and the flexible film 22 is formed. The stage 2 having the deaeration chamber 4 and the pressing force of the air cylinder 11 cooperate with the frame 13a on the peripheral edge of the stage 2 to sandwich the flexible film between the frames 13b and uniformly on the upper surface of the flexible film. A pressurizing head 1 having a pressurizing chamber 3 to which gas is supplied from a gas inlet 10 for applying a gas pressure and having a heater 12a for heating a flexible film 22; A vacuum pump 5 for evacuating via a pressure 8 and a pressurizing chamber 3 of the pressurizing head 1 from a gas inlet 10 via a valve 9 And a gas supply device 6 for supplying a pressurized gas.

The base of the flexible film 22 is made of a polyimide resin, and a thermoplastic polyimide resin layer is formed on the surface (side surface of the stage). At the time of hot pressing, the step between the frame portion 13b of the stage 2 and the inner surface is made low so that the flexible film 22 is not broken, and the recesses 14a and 14b are made lower than the inner surface so that the semiconductor chip 21 does not shift. At the same time as the positioning of the semiconductor chip 21, the step with respect to the surface of the semiconductor chip 21 is reduced. Also, these depressions 14a and 14b
A plurality of rows are arranged in a plurality of rows and provided on the inner surface of the stage 2 so as to match the stage of the resin potting apparatus which is the next step. That is, there is an advantage that the flexible film 22 to which the semiconductor chip 21 is stuck can be directly put on the stage of the resin potting apparatus.

The gas supply device 6 includes a gas supply section 7b having a compressor for further increasing the pressure from a nitrogen gas supply pipe in the factory, and a reserve tank 7a for storing the nitrogen gas whose pressure has been increased by the compressor. ing. The gas pressure supplied to the pressurizing chamber 3 by opening the valve 9 can be adjusted to 4 to 25 kg per square centimeter by a pressure regulator (not shown). On the other hand, the heater 12a,
12b can raise the temperature of the peripheral part to about 300 ° C.

Next, the operation of the thermocompression bonding apparatus will be described.
First, the air cylinder 11 is operated to raise the pressure head 1. Next, the semiconductor chip 2 is placed on the stage 2 while the sheet-like member connected to the pad of the semiconductor chip 21 and the wiring pattern of the flexible film 22 is placed on the stage 2.
1 is inserted into the depressions 14a and 14b on the inner surface of the stage 2.

Next, the air cylinder 11 is operated to lower the pressurizing head 1, and the flexible film 22 is sandwiched between the frame portions 13a and 13b. 2. Make sure that it does not get inside. Next, the valve 8 is opened, and the evacuation chamber 4 is evacuated by the vacuum pump 5. As a result, the residual air existing between the flexible film 22 and the semiconductor chip 21 or the gas generated by heating is completely exhausted, and the flexible film 22 is removed from the surface of the semiconductor chip 21 or the stage 2 as shown by the dotted line. Adhere to the inner surface of the The degree of vacuum in the degassing chamber 4 at this time is, for example, about 0.1 Torr.

When the air is evacuated to such a degree of vacuum, the resin adhesive layer of the flexible film 22 melts and adheres. Further, the residual air or gas remaining on the step of the wiring pattern is further strengthened and the residual air or gas in the resin adhesive layer is removed. The valve 9 is opened to supply the high-pressure gas stored in the reserve tank 7 a to the pressurizing chamber 3, and is uniformly pressed on the surface of the flexible film 22 by the gas pressure. For example,
Press with a pressure of 10 kg or more per square centimeter. The pressed flexible film 22 adapts to the surface of the semiconductor chip 21 and the remaining gas and air diffuse into the resin adhesive layer. As a result, the semiconductor chip 21 is completely adhered to and adhered to the flexible film 22 without generating bubbles.

When the attachment is completed, the valve 9 is closed,
A high-pressure gas is discharged from a vent valve (not shown) into the pressurizing chamber 3 to make it into the atmosphere, and the flexible film 22 is cooled. Then, the pressure head 1 is raised by the air cylinder 11.
Subsequently, a vent valve (not shown) of the degassing chamber 4 is opened, and the degassing chamber 4 becomes the atmosphere. The flexible film 22 to which the semiconductor chip 21 is attached is taken out of the stage 2.

FIG. 2 is a diagram showing a configuration of a main part of a thermocompression bonding apparatus according to another embodiment of the present invention. Depending on the product standard of the flexible film 22, there may be a hole. In such a case, as shown in FIG. 2, a flexible film 22a made of polyimide resin, which is the same material, is placed on the flexible film 22.
Then, what is necessary is just to airtightly sandwich and hold between the frame portion 13a and the frame portion 13b and perform thermocompression bonding in the same manner as described above.

Further, by stacking the flexible film 22a on the flexible film 22, the transmission of the gas pressure to the flexible film 22 becomes uniform, and wrinkles or wrinkles are formed on the flexible film 22 to which the semiconductor chip generated during thermocompression bonding is attached. There was no tear.

On the other hand, at the time of thermocompression bonding, the temperature of the flexible film 22 and the semiconductor chip 21 rises quickly.
It is desirable that a heater 15 be provided in the reserve tank 7a to keep the high-pressure gas at a high temperature at all times.

[0019]

As described above, according to the present invention, the flexible film is sandwiched and held between the pressurizing head having the pressurizing chamber and the stage having the degassing chamber, and the pressurizing chamber and the degassing chamber are partitioned. While heating the semiconductor chip to be attached and vacuuming the space between the flexible film and the semiconductor chip in the degassing chamber and introducing high-pressure gas into the pressurizing chamber, the flexible film is pressed down uniformly on the semiconductor chip. Since thermocompression bonding can be performed without generating bubbles between the flexible film and the semiconductor chip, there is an effect that highly reliable quality can be obtained.

Further, by using a flexible film itself deformed by high-pressure gas as a pressing member for the semiconductor chip, a plurality of semiconductor chips can be mounted on the stage, and the height of each of the semiconductor chips can be increased. As a result, the flexible film is deformed according to the pressure and transmits the pressure, so that the productivity can be improved without adjusting the parallelism between the pressing head and the stage as in a conventional thermocompression bonding apparatus.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a configuration of a main part of a thermocompression bonding apparatus according to another embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of an example of a conventional thermocompression bonding apparatus.

FIG. 4 is a diagram showing a bonding state for explaining a conventional problem.

[Explanation of symbols]

 1, 16 pressure head 2, 17 stage 3 pressure chamber 4 deaeration chamber 5 vacuum pump 6 gas supply device 7a reserve tank 7b gas supply unit 8, 9 valve 10 gas inlet 11 air cylinder 12a, 12b, 15 heater 13a , 13b Frame portion 14a, 14b recess 18a, 18b Heater block 19 Load cell 20a, 20b Level adjuster 21 Semiconductor chip 22, 22a Flexible film 23 Bubbles 24 Film base 25 Resin adhesive layer 26 Wiring

Claims (4)

[Claims] 1. A thermocompression bonding method in which a plurality of semiconductor chips connected to the wiring pattern are previously bonded to the flexible film on which a wiring pattern is formed and to which a thermal adhesive resin layer is applied, via the thermal adhesive resin layer. A first frame-shaped member having a peripheral portion protruding, the flexible film being placed together with the semiconductor chip, and
And a second frame-shaped member which sandwiches the peripheral portion of the flexible film mounted on the stage in cooperation with the first frame-shaped member is formed in the peripheral portion. A pressure head having a second heating heater therein, a gas supply device for supplying a high pressure gas to a space between the flexible film and the pressure head mounted on the stage, and a gas supply device mounted on the stage. A vacuum exhaust device for evacuating a space between the flexible film and the semiconductor chip, and pressing means for moving the pressure head and the stage to sandwich the flexible film. Thermocompression bonding equipment. 2. The thermocompression bonding apparatus according to claim 1, wherein a recess is formed in the stage so that a surface thereof protrudes by a predetermined height and the semiconductor chip enters. 3. The thermocompression bonding apparatus according to claim 1, wherein a film-like member of the same quality as the flexible film is interposed between the pressure head and the flexible film. 4. The thermocompression bonding apparatus according to claim 1, further comprising heating means for heating the high-pressure gas.