JP3513793B2 - Tape structure for pressure bonding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-bonding interposition used when pressure-bonding a flexible film for forming a protective layer on a surface of a semiconductor chip for protection of the semiconductor device during manufacturing of the semiconductor device. It relates to the tape structure.

[0002]

2. Description of the Related Art In order to improve the reliability of a semiconductor device, it is necessary to provide it with heat resistance and moisture resistance. For that purpose, the surface of a semiconductor chip is covered with a protective layer. . A flexible film having a heat-adhesive resin layer is used as the protective layer, and the semiconductor chip and the flexible film are pressure-bonded while being heated to cover the semiconductor chip with the protective layer. The thermocompression bonding is performed by pressing the pressure head from the flexible film side of the flexible film with a semiconductor chip placed on the heating stage of the thermocompression bonding apparatus. At this time, if the pressure head is directly pressed against the flexible film, the flexible film adheres to the pressure head due to heat when pressure-bonded, and the flexible film cannot be peeled off unless the temperature of the pressure head is lowered. Workability was poor. Therefore, a single layer intervening tape made of polyimide, silicon rubber, Teflon sheet or the like is interposed between the pressure head and the flexible film.

[0003]

However, the above-described conventional pressure-bonding intervening tape structure may cause the following problems. The surface of the semiconductor chip 1 is covered with a flexible film 2, and the flexible film 2 has a circuit 3 incorporated in a base film portion 2a and is covered with a cover film 2b as shown in FIG. The flexible tape 2 is covered with the interposing tape 4, and the pressure head 5 is pressed against the pressure-sensitive adhesive to press it. Therefore, when the flexible film 2 has large irregularities on the surface of the semiconductor chip 1, the pressure head 5
Even when pressing, the unevenness due to the circuit 3 becomes an obstacle when the flexible film 2 is adhered to the surface of the semiconductor chip 1, and a part which is not adhered is generated between the flexible film 2 and the semiconductor chip 1. There is a risk that The cause of this non-adhered portion is shown in FIG.
As shown in (a), in addition to the case where there is a large unevenness between the semiconductor chip 1 and the flexible film 2, as shown in (b) of the same figure, the pressure head 5 and the semiconductor chip 1 are kept parallel to each other. In some cases, the thermocompression bonding work is performed in the state where the product is not dripping.

Further, as shown in FIG. 5, the semiconductor chip 1
And the flexible film 2 are temporarily joined at the temporary joining portion 2c and placed on the heating stage 6 of the thermocompression bonding apparatus, and the intervening tape 4 having the hardness of 50 is interposed between the flexible film 2 and the pressure head 5. When silicon rubber is used, a force in the direction of expanding the flexible film 2 acts on the flexible film 2 due to elastic deformation or thermal expansion of the silicon rubber. However, since the flexible film 2 is temporarily bonded to the semiconductor chip 1 at the temporary bonding portion 2c, the temporary bonding portion 2c resists the force, and the flexible film 2 is wrinkled near the temporary bonding portion 2c. May occur. Moreover, the wrinkles generated at this time cannot be corrected in the subsequent steps.

Therefore, according to the present invention, when the semiconductor chip and the flexible film are heated and pressure-bonded, a portion which is not adhered to the semiconductor chip and the flexible film is not generated, and wrinkles are prevented from being generated on the flexible film. It is an object of the present invention to provide a tape structure for pressure-bonding intervention.

[0006]

As a technical means for achieving the above object, the tape structure for press-bonding interposition according to the present invention has a flexible film having a heat-adhesive resin layer applied to a semiconductor chip as a pressure head. In the pressure-bonding intervening tape structure that is interposed between the flexible film and the pressure head when pressing and thermocompression bonding, a structure in which a fluidized layer having fluidity is sandwiched between heat transfer layers made of heat-resistant synthetic resin It is characterized by having.

A semiconductor chip is placed on the heating stage,
A flexible film is covered on this, and this tape for press-bonding is covered. Press the pressure head from above,
Apply heat and pressure. At the time of pressure bonding, the fluidity of the fluidized layer deforms according to the shape of the flexible film or the circuit, the flexible film is uniformly pressed, and its thermal adhesiveness evenly adheres to the semiconductor chip.
For this reason, there will be no part that is not adhered.

Further, in the tape structure for pressure-bonding interposition according to the present invention, the thickness of the heat transfer layer is changed between the front and back sides of the fluidized bed, and the heat transfer layer on the side in contact with the pressure head is thick. It is characterized by

By bringing the thick heat transfer layer into contact with the pressure head, deformation of the heat transfer layer during thermocompression bonding is small,
Further, when heated and pressed, the peelability from the pressing head becomes good. Then, by contacting the flexible film with a thin heat transfer layer, it is easily deformed together with the fluidized bed and conforms to the surface shape of the flexible film, and since the thermal expansion and elastic modulus are small, the force in the direction of spreading the flexible film Has almost no effect,
Suppresses wrinkles on the flexible film.

The pressure-bonding intervening tape structure according to the invention of claim 2 is characterized in that the fluidized bed is made of synthetic resin having fluidity by heating.

When the semiconductor chip and the flexible film are pressure-bonded, the fluidized bed is heated to lower its viscosity and increase its fluidity. When the pressure-bonding work is completed and the temperature is lowered, the viscosity is restored and the flexible film is covered.

Further, the tape structure for press-bonding interposition according to the invention of claim 3 is characterized in that the fluidized layer is constituted by a silicon-based adhesive.

Further, the tape structure for press-bonding interposition according to the invention of claim 4 is characterized in that the heat transfer layer is made of a polyimide resin.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The tape structure for pressure-bonding interposition according to the present invention will be specifically described below based on the illustrated preferred embodiments. FIG. 1 is a sectional view of a pressure-bonding intervening tape 10 according to the present invention, which has a three-layer structure in which a fluidized layer 13 is sandwiched between a first heat transfer layer 11 and a second heat transfer layer 12. The first heat transfer layer 11 and the second heat transfer layer 12 are both made of a polyimide resin, and Kapton (trade name) manufactured by Toray DuPont is used in this embodiment. The thickness of the first heat transfer layer 11 is made larger than the thickness of the second heat transfer layer 12. The fluidized bed 13 is made of a material that has a fluidity by decreasing its viscosity when heated, and it is more preferable to select a material that is appropriately hardened by lowering the temperature over time. Uses a silicone adhesive.

FIG. 3 is a schematic view of a thermocompression bonding apparatus 20 for crimping the semiconductor chip 1 and the flexible film 2 using the pressure-bonding intervening tape 10. The bed 21 has a tilting mechanism 22 on it. A lower heater block 23 is provided, and a heating stage 24 is provided on the lower heater block 23. An adsorption hole 24a is provided on the upper surface of the heating stage 24, and the adsorption hole 24a communicates with a suction device (not shown). The semiconductor chip 1 on which the heating stage 24 is mounted is sucked from the suction holes 24a and sucked by the heating stage 24. A pressure head 25 is fixedly arranged below the upper heater block 26 above the heating stage 24. The upper heater block 26 is fixed to a lower portion of a load meter 27 that detects pressure for pressurization, and the load meter 27 is attached to a tip end portion of a drive arm 28.

A slider portion 29 is provided at the base end portion of the drive arm 28, and a rotatable drive screw 31 vertically suspended on the frame 30 and the slider portion 29 are screwed together. . A drive motor 32 is connected to the upper end of the drive screw 31 via an appropriate speed change mechanism. Therefore,
When the drive motor 32 operates, the drive screw 31 rotates, and the slider portion 29 screwed with the drive screw 31 moves in the vertical direction. By this movement, the pressure head 25 linked to the slider portion 29 via the drive arm 28 moves in the same direction, and when the pressure head 25 descends, it cooperates with the heating stage 24 to apply pressure to the heating stage 24. The semiconductor chip 1 and the flexible film 2 arranged between the head 25 and the head 25 are heated and pressed.

FIG. 2 is a view showing a state in which the semiconductor chip 1 and the flexible film 2 are placed on the heating stage 24 for pressure bonding, and the pressure head 25 is lowered. The flexible film 2 is the semiconductor chip 1
The circuit 3 is incorporated in the base film portion 2a which is adhered to, and the cover film 2b is covered on the circuit 3. The semiconductor chip 1 is supplied while being adhered to the flexible film 2 and covered with the pressure-bonding intervening tape 10 so that the pressure-bonding head 25 heats and presses them on the pressure-bonding intervening tape 10. . At this time, the pressure-bonding intervening tape 10 is arranged so that the first heat transfer layer 11 on the thick side faces the pressure head 25.

The operation of the embodiment of the pressure-bonding intervening tape structure according to the present invention constructed as described above will be described below.

As described above, the heating stage 24 is placed on the heating stage 24 and sucked by the suction holes 24a.
The semiconductor chip 1 and the flexible film 2 adsorbed on the surface of the are covered with the interposition tape 10 for pressure bonding, and the pressure head 25 is lowered to press them, and an appropriate pressure is applied. At this time, the pressure intervening tape 10 is heated by the heating stage 24 and the pressure head 25. This heat is transferred from the heat transfer layer 11 to the fluidized bed.
When the fluidized bed 13 is transmitted to the fluidized bed 13, the viscosity of the fluidized bed 13 is reduced to provide fluidity. The fluidity of the fluidized bed 13 causes the fluidized bed 13 to deform along the surface shape of the flexible film 2. Since the heat transfer layer 12 is formed to be thin, the heat transfer layer 12 is also deformed by conforming to the deformation of the fluidized layer 13 on the surface of the flexible film 2. In this state, the semiconductor chip 1 and the flexible film 2 are heated and pressed.
And are evenly pressed and heated over the entire area, and they are surely brought into close contact with each other, and there is no occurrence of a non-closed portion. Then, by being heated, the thermoadhesive resin layer of the flexible film 2 exhibits adhesiveness and is bonded to the semiconductor chip 1.

Semiconductor chip 1 and flexible film 2
The pressure head 25 is raised after the thermocompression bonding with. The first heat transfer layer 11 of the pressure-bonding intervening tape 10 is in close contact with the pressurizing head 25 at the time of pressurization, and the first heat transfer layer 11 is formed to be thick,
Since it has appropriate rigidity, it can be easily peeled from the surface of the pressure head 25. Moreover, the tape 10 for pressure interposition is peeled off from the flexible film 2. For this reason, the pressure-bonding intervening tape 10 and the cover film 2b of the flexible film 2 are selected from materials that have good releasability between them.

In this embodiment, a polyimide resin having a thickness of about 50 μm is used for the first heat transfer layer 11, and good peelability is obtained. Further, as described above, the second heat transfer layer 12 is preferably thick enough to be appropriately deformed according to the surface shape of the flexible film 2 in accordance with the fluidity of the fluidized layer 13, In this embodiment, about 2
When the polyimide resin of 5 μm was used, the semiconductor chip 1 and the flexible film 2 could be surely brought into close contact with each other. Moreover, after the semiconductor chip 1 and the flexible film 2 are pressure-bonded, the pressure-bonding intervening tape 10 could be easily peeled off from the flexible film 2.
Further, it is desirable that the fluidized bed 13 has fluidity when heated as described above, and it is more preferable that the fluidized bed 13 is appropriately hardened over time. In the present embodiment, this fluidized bed 13
When a silicon-based adhesive having a thickness of about 45 μm is used as the semiconductor chip 1, the second heat transfer layer 12 can be appropriately deformed by being deformed according to the surface shape of the flexible film 2. The flexible film 2 could be surely brought into close contact.

Further, the pressure-bonding intervening tape 10 has a sufficient amount of the semiconductor chip 1 to be pressure-bonded so that it does not adhere to the flexible film 2 even if the fluid leaks from the fluidized layer during pressure-bonding. It is desirable that the area be such that it can be included in

Further, as a preparation for thermocompression bonding, it is preferable to heat the pressure-bonding intervening tape 10 at about 160 ° C. for several tens of seconds to dry it. This is because when the fluidized bed absorbs moisture, when it is heated in a thermocompression bonding apparatus,
This is because foaming may occur due to a sudden temperature change, the pressure applied from the pressure head 25 may be buffered, and the flexible film 2 may not be brought into close contact with the semiconductor chip 1 uniformly.

[0024]

As described above, according to the tape structure for pressure interposition according to the present invention, the three-layer structure in which the fluidized layer having fluidity is sandwiched between the heat transfer layers is used. The fluidity of the fluidized bed causes the flexible film to be deformed according to the shape of the flexible film covered with the semiconductor chip. In this state, the flexible film and the semiconductor chip are thermocompression-bonded through the pressure-bonding intervening tape, so that the flexible film can be uniformly pressed and can be securely adhered to each other.

Further, according to the tape structure for pressure-bonding interposition according to the invention of claim 2, since the thick heat transfer layer comes into contact with the pressure head, the heat transfer layer is pressed after completion of the pressure bonding work. It can be easily peeled off from the head. Further, since the thin film heat transfer layer is brought into contact with the flexible film, the heat transfer layer is easily deformed according to the deformation of the fluidized bed. Therefore, the heat transfer layer is deformed in conformity with the surface shape of the flexible film, and the flexible film can be uniformly pressed over the entire area.

Further, according to the tape structure for pressure-bonding interposition according to the third aspect of the present invention, since the fluidized bed has fluidity by being heated, the fluidity of the fluid-bonded tape is maintained when the pressure-bonding interposition tape is stored. Since it does not have it, its management becomes simple.

According to the tape structure for pressure-bonding interposition according to the fourth aspect of the present invention, the fluidized layer is provided with fluidity by being heated, and the flexible film and the semiconductor chip can be reliably brought into close contact with each other.

Further, according to the tape structure for pressure-bonding interposition according to the invention of claim 5, in combination with the structure in which the pressure head side is made thicker, the tape structure can be easily peeled from the pressure head after pressure bonding. In addition, in combination with the structure in which the flexible film side is thin, thermal expansion and elastic modulus are reduced, and it is possible to suppress the force in the direction in which the flexible film is expanded.
It is possible to prevent wrinkles from occurring on the flexible film.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pressure-bonding intervening tape having a structure according to the present invention.

FIG. 2 is a schematic view for explaining a state in which a flexible film and a semiconductor chip are pressure-bonded by a pressure-bonding intervening tape having a structure according to the present invention, a part of which is cut and shown.

FIG. 3 is a schematic view of an example of a thermocompression bonding apparatus for bonding a semiconductor chip and a flexible film to each other.

FIG. 4 is a view for explaining a problem in the conventional crimping work, and is a partial cross-sectional view corresponding to FIG.

FIG. 5 is a diagram for explaining a problem in the conventional crimping work, and is a partial cross-sectional view corresponding to FIG. 2.

[Explanation of symbols]

1 semiconductor chip 2 flexible film 10 Crimping tape 11 First heat transfer layer 12 Second heat transfer layer 13 Fluidized bed 20 Thermocompression bonding equipment 24 heating stage 25 pressure head

Claims (4)

(57) [Claims] 1. When a flexible film having a heat-adhesive resin layer is pressed against a semiconductor chip by a pressure head to heat-compress it, a flow is generated in a tape structure for pressure-bonding interposed between the flexible film and the pressure head. A fluidized bed having heat resistance is sandwiched between heat transfer layers made of heat-resistant synthetic resin , The thickness of the heat transfer layer is set to the front and back of the fluidized bed.
The heat transfer layer on the side in contact with the pressure head
Tape for press-fitting interposition, characterized in that
Construction. 2. The tape structure for pressure-bonding interposition according to claim 1, wherein the fluidized bed is made of synthetic resin having fluidity when heated. 3. A process according to claim 1 or claim 2 noise, characterized in that the fluidized bed constituted by a silicon-based adhesive
The tape structure for press-bonding intervention described therein. 4. Any of claims 1 to 3, characterized in that the heat transfer layer was composed of the polyimide resin
The tape structure for pressure-bonding interposition according to Crab .