JPH11219872A - Low-pressure wafer bonding system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-pressure wafer bonding system that reduces damages to each wafer, when a plurality of wafers are permanently bonded onto a carrier plate in a batch. SOLUTION: A carrier plate 12, on which a plurality of silicon wafers W have been temporarily bonded, is placed on a table 13. A pressure reducing cover 15 is placed on a main body pedestal 11 to seal the table 13. An air suction pump 20 is used to make negative pressure inside of the pressure reducing cover 15. If a doughnut-shaped pressure balloon 14 is blown up by an air supply pump 18, the bonding surface between each wafer W and the plate 12 is degassed due to the decompression effect in the cover 15. Wafers W placed around the plate axis line are bonded with pressure relatively gently on the carrier plate 12 in a batch by the balloon 14. As a result, damages to the wafers W is reduced, when they are bonded permanently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decompression bonding apparatus for wafers, and more particularly to a method for permanently bonding a plurality of wafers temporarily bonded to a carrier plate used in a surface polishing apparatus for polishing the surface of a wafer. The present invention relates to a wafer decompression bonding apparatus.

[0002]

2. Description of the Related Art For example, in polishing the surface of a silicon wafer, the wafer is polished and fixed to a carrier plate, and then put into a surface polishing apparatus to polish the surface of the wafer. When bonding the wafer to this carrier plate, wax is applied to the back surface of the wafer in advance, and then a plurality of wafers are temporarily bonded on the carrier plate at predetermined intervals around the plate axis. The actual bonding was performed by pressing and bonding the wafers using a bonding apparatus.

Conventionally, an apparatus for pressing and bonding a wafer to such a carrier plate has been disclosed in, for example,
As described in Japanese Patent Publication No. 245366, there is known a wafer decompression bonding apparatus for performing the actual bonding under reduced pressure. Hereinafter, this will be described with reference to the explanatory view of the wafer decompression bonding apparatus according to the conventional means of FIG. As shown in FIG. 4, this apparatus comprises a carrier plate 111 on which a predetermined number of wafers 110 are temporarily bonded on a main body base 100.
A large press plate 103 is provided above the main body pedestal 100 to permanently adhere the wafers 110 collectively. The press plate 103 is attached to the pressure reducing cover 102 that seals the periphery of the pedestal 105 so as to be able to move up and down. The air cylinder 1
04 is used.

At the time of actual bonding of a wafer, a carrier plate 111 with a wafer 110 is placed on a pedestal 105,
Thereafter, the decompression cover 102 is put on the main body base 100 so as to seal the periphery of the pedestal 105 and the decompression chamber 101
To form Then, the pressure in the decompression chamber 101 is reduced to a negative pressure by the air suction means 108 through the pipe 106, and the rod of the air cylinder 104 is protruded to lower the press plate 103, thereby pressing the wafer 110. As a result, each wafer 110 and carrier plate 111
Each wafer 110 is pressed by the press plate 103 while the adhesive surface with the carrier plate 11 is being degassed.
Pressed and bonded to 1. Then, the inside of the decompression chamber 101 is returned to normal pressure. In this way, the actual bonding without bubbles between the wafer 110 and the carrier plate 111 is performed.

[0005]

However, in such a conventional wafer decompression bonding apparatus, since the surface of the wafer 110 before polishing is generally poor, a hard press By the plate 103,
When each wafer 110 is pressed and bonded to the carrier plate 111, a large pressure is locally applied to the wafer 110, and there is a possibility that the wafer 110 may be damaged.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wafer decompression bonding apparatus capable of reducing damage to each wafer when a plurality of wafers are permanently bonded to a carrier plate at a time. I have. Another object of the present invention is to provide a wafer decompression bonding apparatus capable of reducing equipment costs. further,
SUMMARY OF THE INVENTION It is an object of the present invention to reduce the cost of a pressure balloon and to provide a wafer decompression bonding apparatus in which pressure bonding of a pressure balloon to a wafer is relatively soft.

[0007]

According to a first aspect of the present invention, there is provided a carrier plate in which a plurality of wafers are bonded on one side at predetermined intervals around a plate axis via a wax, and the wafer is formed by the wax. A pedestal on which the temporarily bonded carrier plate is placed, and a decompression cover for sealing the carrier plate placed on this pedestal from the outside,
Air suction means for decompressing the internal space of the decompression cover,
An annular pressure balloon, which is provided in the decompression cover, is inflated by gas injection, and pressurizes and adheres each wafer disposed on one surface of the carrier plate to the carrier plate at once. This is a wafer decompression bonding apparatus provided with gas injection means for injecting gas into the pressurized balloon.

[0008] The type and size of the wafer are not limited. For example, a silicon wafer or a gallium arsenide wafer may be used. The number of wafers bonded to the carrier plate is not limited as long as the wafers can be bonded at predetermined intervals along the axis of the plate. For example, two, three, four
Or five or more. As the air suction means, various air suction pumps capable of sucking air from an internal space sealed by a decompression cover can be employed. It is preferable that the degree of reduced pressure in the reduced-pressure cover by this apparatus be vacuum or closer to it because the degassing force of the bonding surface between each wafer and the carrier plate becomes large.

As the pressurized balloon, for example, a donut-shaped rubber balloon (balloon) can be used. The point is that if it is an annular balloon that can be expanded or contracted by injecting or discharging gas and that can press and bond multiple wafers on the carrier plate at once, The appearance shape, size, material, degree of expansion and contraction, and the like when viewed are not limited. As the gas injection means, for example, pumps such as a compressor capable of injecting gas into the pressurized balloon can be employed. The gas referred to here is air or various inert gases. The amount of gas injected into the pressurized balloon inflated by the gas injecting means is controlled by the control device so that the wafer is not excessively pressurized and damaged when the balloon is inflated. Further, the pedestal may have a heater capable of heating the carrier plate. further,
The wafer decompression bonding apparatus may be provided with driving means (for example, an actuator such as an air cylinder, a screw feed mechanism, an electric motor, etc.) for raising and lowering the pressure balloon.

According to a second aspect of the present invention, the pressurized balloon is mounted on a balloon mounting base provided on an inner surface of the decompression cover, and the gas injection means is disposed inside the balloon mounting base. The wafer decompression bonding apparatus according to claim 1, further comprising a gas path provided and a gas supply pump provided outside. The size of the piping of the gas path in the balloon mounting base and the routing path may be arbitrary.

According to a third aspect of the present invention, there is provided the wafer decompression bonding apparatus according to the first or second aspect, wherein the pressure balloon is made of rubber.

[0012]

According to the present invention, a carrier plate on which a plurality of wafers are temporarily bonded via wax is placed on a pedestal, and then a pressure reducing cover is put on the pedestal so as to seal the periphery of the pedestal. Then, the internal space of the pressure reducing cover sealed by the air suction means is reduced to a negative pressure, and then the annular pressure balloon provided in the pressure reducing cover is inflated using the gas injection means. Due to the effect, while the bonding surface between each wafer and the carrier plate is degassed, the wafers temporarily bonded at predetermined intervals around the plate axis by the pressure balloon are relatively softly added to the carrier plate at once. Pressed and bonded.

As a result, it is possible to reduce damage to each wafer during the actual bonding of the wafers. In addition, since the shape of the pressurized balloon is an annular shape that can press the wafers arranged around the plate axis at a time, each of these wafers is applied with a substantially equal force according to the principle of Archimedes. , And are uniformly pressed in the plane. As a result, the damage of each wafer at the time of the actual bonding can be reduced substantially uniformly.

In particular, according to the second aspect of the present invention, the pressurized balloon attached to the balloon mounting base of the decompression cover is annularly formed by the gas injected from the gas supply pump through the gas passage in the balloon mounting base. The wafer is collectively pressed and adhered to the carrier plate by the expanded pressure balloon. Since such a relatively inexpensive configuration is employed, equipment costs can be reduced.

Further, according to the third aspect of the present invention, since the pressure balloon is made of rubber, the cost of the pressure balloon can be reduced, and the pressure of the pressure balloon to the wafer becomes softer. -The damage of the wafer at the time of bonding can be further reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, a wafer decompression bonding apparatus according to an embodiment of the present invention will be described. FIG. 1 is an explanatory view showing a state before sealing a vacuum cover of a wafer vacuum bonding apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of the main body base on which the carrier plate is arranged. FIG. 3 is an explanatory view showing a final bonding step of the wafer after sealing the reduced-pressure cover. 1 and 2, reference numeral 10 denotes a wafer decompression bonding apparatus according to an embodiment of the present invention. In this wafer decompression bonding apparatus 10, five silicon wafers W are temporarily bonded by wax on a main body base 11. This apparatus is provided with a pedestal 13 of a carrier plate 12, and a donut-shaped pressurized balloon 14 for permanently bonding all the silicon wafers W at a time above the main body base 11.

The pressurizing balloon 14 is mounted on a thick disk-shaped balloon mounting base 16 fixed to the inner surface of a decompression cover 15 that seals the periphery of the pedestal 13. In particular,
On the peripheral side surface of the lower end portion of the balloon mounting base 16, a pressure rubber balloon 14 made of a rubber sheet having a thickness of 0.5 to 1 mm is formed.
And the center of the pressurizing balloon 14 is fixed to the center of the lower surface of the balloon mounting base 16. Thereby, the pressurized balloon 14 expands into a donut shape when compressed air is injected. In addition, the decompression cover 1
5 can be moved up and down by inserting and removing the rod 17a of the air cylinder 17. The pressure reducing cover 15 is circular in plan view, and has a sealing material 15a on its lower end surface.
Is provided around.

Inside the balloon mount 16, compressed air (or atmospheric pressure air) is supplied from an air supply pump (gas supply pump) 18, which is an example of an external gas injection means, via a supply pipe 18 a. ) Into the pressurizing balloon 14 is formed. Further, on the main body base 11, a circular cover receiving tray 19 is fixedly attached to the lower edge portion of the decompression cover 15 in a plan view. That is, the pedestal 13 is fixed to the inner surface of the cover tray 19. Also, on the outer peripheral portion of the cover tray 19,
One end of the pressure reducing tube 20a is connected. This decompression tube 2
The other end of Oa is connected to an air suction pump 20 which is an example of air suction means for reducing the pressure inside the pressure reducing cover 15.

Next, the operation of the wafer decompression bonding apparatus 10 according to this embodiment will be described. As shown in FIG. 1, a carrier plate 12 on which five silicon wafers W are temporarily bonded by wax is placed on a pedestal 13, and thereafter, a rod 17 a of an air cylinder 17 is protruded to
Of the decompression cover 15 so that the periphery of the
9 on top. Then, as shown in FIG. 3, the internal space of the pressure reducing cover 15 sealed by the air suction pump 20 is reduced to a negative pressure, and then the air supply pump 18 is operated to mount the balloon fixed on the inner surface of the pressure reducing cover 15. The pressurizing balloon 14 of the base 16 is inflated into a donut shape (see a solid line state → a dashed line state → a two-dot chain line state in FIG. 3).

As a result, each silicon wafer W and the carrier plate 12
Is gradually degassed outward from the center of the wafer (see the dashed line in FIG. 3) to the outer periphery of the wafer (see the dashed line in FIG. 3). At the same time, the silicon wafers W temporarily bonded by the pressure balloon 14 at predetermined intervals around the plate axis are collectively bonded to one surface of the carrier plate 12 with a relatively small force. Is performed with sufficient pressure and adhesion. At this time, the supply amount of the compressed air by the air supply pump 18 is adjusted using a control device (not shown) so as not to damage each silicon wafer W. Thereby, the damage of each silicon wafer W at the time of the actual bonding of the wafers can be reduced. In addition, since the shape of the pressurizing balloon 14 is a donut shape capable of simultaneously pressing the silicon wafers W arranged in concentric circles, each of the silicon wafers W is applied with a substantially equal force by Archimedes' principle. Pressurized. As a result, the damage of each silicon wafer W at the time of the actual bonding is substantially uniformly reduced.

In this embodiment, the wafer decompression bonding apparatus 1
0, the main body pedestal 11, pedestal 13,
Since it is composed of relatively inexpensive components such as the pressurizing balloon 14, the decompression cover 15, the balloon mounting base 16, the air cylinder 17, the air supply pump 18 and the air suction pump 20, the equipment cost can be reduced. In addition, since the pressure balloon 14 is made of rubber, the cost of the pressure balloon 14 can be reduced, and the pressure bonding of the pressure balloon 14 to the silicon wafer W becomes softer. Can be further reduced.

[0022]

According to the present invention, as the pressure mechanism for permanently bonding each temporarily bonded wafer to the carrier plate under a reduced pressure environment, a mechanism for expanding and contracting an annular pressure balloon by gas injection means is employed. Therefore, while degassing the bonding surface between each wafer and the carrier plate by the decompression effect, each wafer temporarily bonded at a predetermined interval along the plate axis is relatively soft to the carrier plate by the pressure balloon, and Pressurizing and bonding can be performed at once. Thereby, the damage of each wafer at the time of the actual bonding of the wafer can be reduced. Moreover, since the shape of the pressurized balloon is annular, damage to each wafer at the time of final bonding can be substantially uniformly reduced.

In particular, according to the second aspect of the present invention, since the pressurized balloon is provided on the balloon mounting base provided on the inner surface of the decompression cover and the gas supply pump is used as the gas injection means, the configuration is relatively inexpensive. And the equipment cost can be reduced.

Further, according to the third aspect of the present invention, since the pressure balloon is made of rubber, the manufacturing cost of the pressure balloon can be reduced, and the pressure bonding of the pressure balloon to the wafer becomes softer. Damage to the wafer during pressing and bonding can be further reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state before sealing a vacuum cover of a wafer vacuum bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a main body base on which a carrier plate according to one embodiment of the present invention is arranged.

FIG. 3 is an explanatory view showing a final bonding step of a wafer after sealing a reduced-pressure cover according to one embodiment of the present invention.

FIG. 4 is an explanatory view of a wafer decompression bonding apparatus according to a conventional means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Wafer decompression bonding apparatus, 12 Carrier plate, 13 pedestals, 14 Pressurized balloon, 15 Decompression cover, 16 Balloon mounting base, 16a Air path (gas path), 18 Air supply pump (gas injection means), 20 Air suction pump (Air suction means), W silicon wafer (wafer).

Continuing on the front page (72) Inventor Tatsuyoshi Kobayashi Mitsubishi Materials Silicon Co., Ltd. 1-5-1, Otemachi, Chiyoda-ku, Tokyo

Claims (3)

[Claims] 1. A carrier plate on which a plurality of wafers are bonded on one side at predetermined intervals around a plate axis via wax, and a pedestal on which a carrier plate on which wafers are temporarily bonded by wax is mounted. A pressure reducing cover for sealing the carrier plate placed on the pedestal from the outside, an air suction means for reducing the pressure in the internal space of the pressure reducing cover, and provided in the pressure reducing cover and expanded by gas injection. An annular pressurizing balloon for pressurizing and adhering each wafer arranged on one side of the carrier plate to the carrier plate at a time, and gas injecting means for injecting gas into the pressurizing balloon. Wafer decompression bonding equipment. 2. The pressure balloon is attached to a balloon mounting base provided on the inner surface of the decompression cover, and the gas injection means includes a gas passage disposed inside the balloon mounting base, The wafer pressure reduction bonding apparatus according to claim 1, further comprising a gas supply pump provided outside. 3. The wafer pressure reducing and bonding apparatus according to claim 1, wherein the pressure balloon is made of rubber.