JP3846007B2 - Wafer vacuum bonding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer vacuum bonding apparatus, and more particularly to a wafer vacuum bonding apparatus for collectively bonding a plurality of wafers temporarily bonded to a carrier plate used in a surface polishing apparatus for polishing a wafer surface.
[0002]
[Prior art]
For example, in the surface polishing of a silicon wafer, the wafer is bonded and fixed to a carrier plate, which is put into a surface polishing apparatus to perform surface polishing of the wafer. When bonding the wafer to the carrier plate, a 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 along the plate axis, and then the wafer The wafer was bonded by pressurizing and bonding using a bonding apparatus.
[0003]
Conventionally, as an apparatus for pressurizing and adhering a wafer to such a carrier plate, for example, a wafer depressurizing apparatus that performs this main bonding under reduced pressure, such as that described in JP-A-63-245366, is known. ing. Hereinafter, this will be described with reference to the explanatory view of the wafer vacuum bonding apparatus according to the conventional means of FIG.
As shown in FIG. 4, in this apparatus, a pedestal 105 of a carrier plate 111 on which a predetermined number of wafers 110 are temporarily bonded is provided on a main body gantry 100, and each wafer 110 is collectively placed above the main body gantry 100. Thus, a large press plate 103 to be bonded is provided. The press plate 103 is attached to a decompression cover 102 that seals the periphery of the pedestal 105 so as to be lifted and lowered. An air cylinder 104 is used for the elevation.
[0004]
At the time of wafer main bonding, the carrier plate 111 with the wafer 110 is placed on the pedestal 105, and then the decompression cover 102 is placed on the main frame 100 so as to seal the periphery of the pedestal 105 to form the decompression chamber 101. To do. Then, the decompression chamber 101 is made negative pressure by the air suction means 108 through the pipe 106, the rod of the air cylinder 104 is protruded, and the press plate 103 is lowered to pressurize the wafer 110. As a result, the wafer 110 is pressed and bonded to the carrier plate 111 by the press plate 103 while the bonding surface between each wafer 110 and the carrier plate 111 is degassed due to the decompression effect. Thereafter, the inside of the decompression chamber 101 is returned to normal pressure. By doing in this way, this adhesion | attachment in which a bubble does not exist between the wafer 110 and the carrier plate 111 is performed.
[0005]
[Problems to be solved by the invention]
However, in such a conventional wafer pressure reduction bonding apparatus, generally, the wafer 110 before polishing has a poor surface flatness. Therefore, when the wafer is bonded, each wafer 110 is held by a hard press plate 103. When the plate 111 is pressed and bonded, a large pressure is locally applied to the wafer 110, which may cause damage to the wafer 110.
[0006]
OBJECT OF THE INVENTION
Therefore, an object of the present invention is to provide a wafer vacuum bonding apparatus that can reduce damage to each wafer when a plurality of wafers are collectively bonded to a carrier plate.
Another object of the present invention is to provide a wafer vacuum bonding apparatus that can reduce equipment costs.
Furthermore, an object of the present invention is to provide a wafer pressure-reducing adhesive device that reduces the cost of the pressure balloon and that is relatively soft to the pressure balloon.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is a carrier plate in which a plurality of wafers are bonded on one side at a predetermined interval on a concentric circle centered on the plate axis via wax, and a carrier plate in which the wafer is temporarily bonded by wax. , A decompression cover for sealing the carrier plate placed on the pedestal from the outside, an air suction means for decompressing the internal space of the decompression cover, and an inner surface of the decompression cover. A balloon-shaped balloon mounting base part and a circular rubber sheet, and the outer peripheral part of the rubber sheet is in close contact with the outer peripheral surface of the lower end part of the balloon mounting base part, and the central part of the rubber sheet is the balloon mounting base by being affixed to the lower surface center portion of the section expands in a donut shape by injection of gas, each wafer disposed on one side of the carrier plate, collectively Transverse and pressure balloon pressure-bonded to the serial carrier plate, and a gas injection means for injecting a gas into the pressurized balloon, the pressure balloon, for each wafer, the first wafer center Then, the wafer pressure-reducing bonding apparatus has a structure that makes line contact and then expands so as to gradually expand the contact range toward the axis side of the carrier plate and toward the outer peripheral side of the carrier plate .
[0008]
There are no restrictions on the type or size of the wafer. 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 it can be bonded at predetermined intervals along the plate axis. For example, it may be 2, 3, 4, 5, or more.
As the air suction means, various air suction pumps that can suck air from the internal space sealed by the decompression cover can be employed. The degree of decompression in the decompression cover by this apparatus is preferably a vacuum or close to it because the deaeration force on the bonding surface between each wafer and the carrier plate is increased.
[0009]
The pressure balloon is a balloon (balloon) which is made of a circular rubber sheet and expands into a donut shape by gas injection. In short, it is possible to or expand and contract by injection or discharge of the gas, moreover with a plurality of wafers can be to pressure-bonding together on the carrier plate, for each wafer, the first If it is a donut-shaped balloon that is inflatable so as to be in line contact across the center of the wafer and then gradually expand the contact range toward the axis side and outer periphery of the carrier plate , The degree of contraction is not limited.
As the gas injection means, pumps such as a compressor that can inject gas into the pressurized balloon can be employed. The gas here is air, various inert gases, or the like. The amount of gas injected into the pressurized balloon inflated by the gas injection means is controlled by the control device so that the wafer is not excessively pressurized and damaged when the balloon is inflated.
The pedestal may be provided with a heater that can heat the carrier plate.
Further, the wafer pressure reducing and bonding apparatus may be provided with driving means for moving the pressure balloon up and down (for example, an actuator such as an air cylinder, a screw feed mechanism, an electric motor, etc.).
[0010]
The invention according to claim 2, the gas injection means, the balloon and the loading stand portion inside arranged gaseous path, wafer vacuum according to claim 1 having a gas supply pump provided outside It is a bonding device. The size of the gas path in the balloon mounting base and the routing path may be arbitrary.
[0011]
[Action]
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 decompression cover is placed over the periphery of the pedestal so as to be sealed. Then, the internal space of the pressure-reducing cover sealed by the air suction means is made negative, and then the doughnut-shaped pressure balloon provided in the pressure-reducing cover is inflated using the gas injection means . As a result, the pressure balloon first makes line contact with each wafer across the center of the wafer, and then the contact range gradually expands toward the carrier plate axis and the outer periphery of the carrier plate. Go inflating as you do. Moreover, due to the pressure reducing effect of the air suction means, the wafers temporarily bonded at predetermined intervals along the plate axis are collectively collected by the pressurized balloon while the bonding surface between each wafer and the carrier plate is deaerated. It is relatively softly pressed and bonded to the carrier plate.
[0012]
Thereby, the damage of each wafer at the time of this wafer main adhesion | attachment can be reduced. In addition, since the shape of the pressure balloon is a donut shape that can press each wafer arranged around the plate axis in a lump, according to Archimedes's principle, each of these wafers has a substantially equal force. Thus, the pressure is uniformly applied in the plane. As a result, damage to each wafer during the main bonding can be reduced substantially evenly.
In addition, since the pressure balloon is made of rubber, the cost of the pressure balloon can be reduced, and the pressure balloon can be more softly bonded to the wafer, further reducing the damage to the wafer during pressure and bonding. Can do.
[0013]
In particular, according to the second aspect of the present invention, the pressure balloon attached to the balloon mounting base portion of the decompression cover is expanded into a donut shape by the gas injected from the gas supply pump via the gas path in the balloon mounting base portion. By doing so, the wafer is collectively pressed and bonded to the carrier plate by the expanded pressure balloon. Since such a relatively inexpensive configuration is adopted, the equipment cost can be reduced .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. First, a wafer vacuum bonding apparatus according to one 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 one embodiment of the present invention. FIG. 2 is a plan view of the main frame on which the carrier plate is arranged. FIG. 3 is an explanatory view showing the final bonding process of the wafer after sealing the reduced pressure cover.
1 and 2, reference numeral 10 denotes a wafer vacuum bonding apparatus according to an embodiment of the present invention. This wafer vacuum bonding apparatus 10 has five silicon wafers W temporarily bonded to a main frame 11 with wax. The carrier plate 12 is provided with a pedestal 13, and a donut-shaped pressurizing balloon 14 for collectively bonding the silicon wafers W is disposed above the main body gantry 11.
[0015]
The pressurizing balloon 14 is mounted on a thick disk-shaped balloon mounting base 16 fixed to the inner surface of the decompression cover 15 that seals the periphery of the base 13. Specifically, the outer peripheral portion of the pressure balloon 14 made of a rubber sheet having a circular thickness of 0.5 to 1 mm is in close contact with the peripheral side surface of the lower end portion of the balloon mounting base 16, and the balloon mounting base 16 The central portion of the pressurizing balloon 14 is fixed to the central portion of the lower surface. As a result, the pressurized balloon 14 swells into a donut shape when compressed air is injected. The decompression cover 15 can be moved up and down by inserting and removing the rod 17a of the air cylinder 17. The decompression cover 15 is circular in plan view, and a sealing material 15a is provided around the lower end surface thereof.
[0016]
Compressed air (or atmospheric pressure air) is applied to the inside of the balloon mounting base 16 from an air supply pump (gas supply pump) 18 which is an example of an external gas injection means via a supply pipe 18a. An air passage (gas passage) 16a for supplying the pressure balloon 14 is formed.
Further, a circular cover tray 19 is fixed on the main body base 11 in a plan view that can be brought into contact with the lower edge of the decompression cover 15. That is, the base 13 is fixed to the inner surface of the cover tray 19. Further, one end portion of the pressure reducing tube 20 a is connected to the outer peripheral portion of the cover tray 19. The other end of the decompression tube 20a is connected to an air suction pump 20 which is an example of an air suction means for decompressing the internal space of the decompression cover 15.
[0017]
Next, the operation of the wafer vacuum 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 with wax is placed on a pedestal 13, and then a rod 17 a of an air cylinder 17 is protruded to surround the pedestal 13. The vacuum cover 15 is placed on the governor tray 19 so as to be sealed. Then, as shown in FIG. 3, the internal space of the decompression cover 15 sealed by the air suction pump 20 is made negative, and then the air supply pump 18 is operated to attach the balloon fixed to the inner surface of the decompression cover 15. The pressurizing balloon 14 of the pedestal 16 is inflated into a donut shape (see the solid line state → the one-dot chain line state → the two-dot chain line state in FIG. 3).
[0018]
As a result, due to the pressure reduction effect of the air suction pump 20, the bonding surface between each silicon wafer W and the carrier plate 12 is from the wafer center (see the one-dot chain line in FIG. 3), and the wafer outer periphery (see the two-dot chain line in FIG. 3). ) And gradually degassed outward. At the same time, the silicon wafers W temporarily bonded at predetermined intervals along the plate axis by the pressurizing balloon 14 are collectively bonded to one side of the carrier plate 12 with a relatively small force. Is pressed and bonded with sufficient force.
Note that the amount of compressed air supplied by the air supply pump 18 at this time is adjusted to such an extent that the silicon wafers W are not damaged by using a control device (not shown). Thereby, the damage of each silicon wafer W at the time of this wafer main adhesion | attachment can be reduced. In addition, since the shape of the pressurizing balloon 14 is a donut shape capable of pressing the silicon wafers W arranged in concentric circles at a time, the silicon wafers W have substantially equal forces according to Archimedes' principle. Pressurized. As a result, damage to each silicon wafer W during the main bonding is reduced substantially evenly.
[0019]
In this embodiment, the wafer decompression bonding apparatus 10 is mainly composed of a main body base 11, a pedestal 13, a pressure balloon 14, a decompression cover 15, a balloon mounting base 16, an air cylinder 17, an air supply pump 18, and the like as described above. Since it is configured by relatively inexpensive parts such as the air suction pump 20, the equipment cost can be reduced.
Further, 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. Damage can be further reduced.
[0020]
【The invention's effect】
According to the present invention, each wafer is temporarily bonded as pressurizing mechanism for the adhesion to the carrier plate in a reduced pressure environment, since the pressure balloon donut shape adopted what inflating and deflating the gas injection means, the gas injection By injecting gas into the pressurized balloon by means, the pressurized balloon first makes line contact with each wafer across the center of the wafer and then towards the axial and outer peripheral sides of the carrier plate. The contact area is gradually expanded. At that time, due to the pressure reduction effect, each wafer temporarily bonded at a predetermined interval along the plate axis line while degassing the bonding surface between each wafer and the carrier plate, is relatively soft to the carrier plate by a pressure balloon, And it can be pressed and bonded together. Thereby, the damage of each wafer at the time of this wafer main adhesion | attachment can be reduced. Moreover, since the shape of the pressurized balloon is a donut shape, damage to each wafer during the main bonding can be reduced substantially evenly.
In addition, since the pressure balloon is made of rubber, the manufacturing cost of the pressure balloon can be reduced, and the pressure balloon can be pressed more softly on the wafer, further reducing damage to the wafer during pressure and bonding. can do.
[0021]
In particular, according to the second aspect of the present invention, the pressure balloon is provided on the balloon mounting base provided on the inner surface of the decompression cover, and the gas supply pump is employed as the gas injection means. Cost can be 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 one embodiment of the present invention.
FIG. 2 is a plan view of a main frame on which a carrier plate according to an embodiment of the present invention is arranged.
FIG. 3 is an explanatory view showing a main bonding step of the wafer after sealing the vacuum cover according to one embodiment of the present invention.
FIG. 4 is an explanatory view of a wafer vacuum bonding apparatus according to a conventional means.
[Explanation of symbols]
10 Wafer vacuum bonding equipment,
12 Carrier plate,
13 pedestal,
14 Pressurized balloon,
15 decompression cover,
16 Balloon mounting base,
16a air passage (gas passage),
18 Air supply pump (gas injection means),
20 Air suction pump (air suction means),
W Silicon wafer (wafer).

Claims (2)

A carrier plate in which a plurality of wafers are bonded on one side at a predetermined interval on a concentric circle centered on the plate axis, via wax,
A pedestal on which a carrier plate to which a wafer is temporarily bonded by wax is placed;
A decompression cover for sealing the carrier plate placed on the pedestal from the outside;
An air suction means for decompressing the internal space of the decompression cover;
A disk-shaped balloon mounting base provided on the inner surface of the decompression cover;
The rubber sheet is made of a circular rubber sheet, and the outer peripheral part of the rubber sheet is closely attached to the outer peripheral surface of the lower end part of the balloon mounting base part, and the central part of the rubber sheet is fixed to the central part of the lower surface of the balloon mounting base part. Thus, a pressure balloon that expands into a donut shape by gas injection and pressurizes and bonds the wafers arranged on one side of the carrier plate to the carrier plate at once,
Gas injection means for injecting gas into the pressurized balloon ,
The pressure balloon first makes a line contact with each wafer across the center of the wafer, and then gradually expands the contact range toward the axis side of the carrier plate and the outer peripheral side of the carrier plate. Wafer vacuum bonding apparatus having a structure that expands like this . 2. The wafer vacuum bonding apparatus according to claim 1, wherein the gas injection means includes a gas passage disposed inside the balloon mounting base and a gas supply pump provided outside. 3.

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