JPH04201174A - Upper shaft mechanism for polishing device - Google Patents

Abstract

PURPOSE:To improve flatness of a wafer intended to be polished by pressurizing approximately the whole surface of the upper surface of a press plate contained in an expandable and oscillating pressure chamber located below an upper shaft and pressing a carrier plate by means of the press plate. CONSTITUTION:A press plate 40 is brought into contact with the upper surface of a carrier plate 81 adhered on the under surface of a wafer 82, and the carrier plate 81 is pressed by means of the press plate 40. When a pressure chamber 50a formed in the upper surface of the press plate 40 is pressurized, a pressure in the pressure chamber 50a is exerted so as to press down the press plate 40. Since the pressure in the pressure chamber 50a is exerted approximately on the whole surface of the press plate 40 and the pressure chamber 50a is expandable and freely oscillated, the pressure is also uniformly exerted throughout the whole surface of the upper surface of the carrier plate 81 and the carrier plate 81 is pressed toward a turn table 80. This constitution improves flatness and smoothness of the wafer 82, especially flatness.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an upper shaft mechanism of a polishing apparatus for polishing a wafer, and more particularly to an upper shaft mechanism for pressing a wafer against a polishing surface.

[Conventional technology]

Single crystal Noricon wafer (hereinafter simply referred to as wafer)
The final finishing step is mechanochemical boring using a polishing device to improve the smoothness of the wafer and give it a mirror finish. Conventionally, the polishing equipment used here rotates the wafer, which is attached to the bottom surface of a carrier plate, independently while dropping a polishing liquid onto the polishing surface of a revolving turntable to which a polishing cloth made of soft elastic material is attached. A press plate attached to the lower end of the upper shaft was used to press the carrier plate from the top surface and polish it. This polishing requires high flatness and smoothness of the wafer, but the polishing accuracy at this time is greatly affected by the flatness of the turntable and the parallelism between the turntable and the press plate. The polishing state of the wafer also changes depending on the point at which pressure is applied to the press plate that presses the plate. This means that the center of the upper surface of the pressing plate is pressed by the upper shaft,
In conventional polishing devices that press the entire top surface of the carrier plate with the bottom surface of the press plate, even if the press plate is flat, it is not an ideal rigid body, so slight deformation occurs due to partial pressure, and the carrier plate The force acting on the top surface is also not uniform. Moreover, a similar situation occurs even in a disc-shaped carrier plate made of ceramics, etc.
Since multiple wafers are bonded to the bottom surface of the carrier plate along the radius of the carrier plate rather than at the center, the pressure point of each wafer being polished is eccentric, which particularly affects the levelness of the wafers. come. The following improved means has been disclosed for the upper shaft mechanism of such a polishing device for pressurizing the carrier plate while rotating. ■ First, as shown in Fig. 4, an elastic hollow body 413 that is filled with liquid or gas at an appropriate pressure to become rubber or the like is provided in the tonneau link 404, which is a rotating disk placed at the lower end of the rotating upper shaft. . The elastic hollow body 413 allows the carrier plate 2 placed on the turntable 403 to
It is pressed from the top surface. By such a means, the upper surface of the carrier plate to which Ueno\401 is bonded is pressed evenly (Utility Model No. 62-1)
65849). ■ Also, as shown in FIG. 5, the carrier plate 52
an outer periphery suppressing device 520 for pressing the vicinity of the outer periphery of 6 toward the turntable 556; and a carrier plate 52.
6 and a central pressing device 536 for pressing the vicinity of the center. A pressure plate 644 is attached to the lower part of the central pressing device 536, and by pressurizing the center of the carrier plate 526, a part of the outer periphery of the wafer 548 is pressed, while a part of the outer periphery of the carrier plate 526 is pressed Pressing is performed by the outer periphery pressing device 520. The central pressing device 536 is a piston device that adjusts the pressing force using compressed air.
The purpose is to equalize the force applied to the wafer polishing surface by adjusting the pressing force of the central pressing device 536 and balancing it with the peripheral pressing device 620 (Japanese Utility Model Publication No. 64-16260).

[Problem to be solved by the invention]

During polishing in a polishing machine, the heat generated by applying pressure to the wafer with soft abrasive grains causes a corrosion reaction to proceed on minute convexities on the wafer, so the polishing heat from this process is also accumulated on the turntable of the machine. Ru. In addition, on the turntable, there is a carrier plate with a diameter of approximately 1/2 or less of the turntable, to which multiple wafers are bonded, and a plurality of carrier plates, for example, four carrier plates, each of which rotates on its own axis. Since the pressure is applied by the upper shaft mechanism, the heat storage portion and the heat radiation portion of the turntable also lack uniformity. Therefore, as polishing progresses, the top surface of the turntable will become extremely loose.
Surface distortion occurs. This distortion is usually a curved deformation centered around the center of the turntable. In such a situation, although the above mechanism for pressing with an elastic hollow body can apply pressure evenly to the upper surface of the carrier plate, since the surface acting on the carrier plate is an elastic body such as rubber, rotation A slight impact from the polished surface inside causes the carrier plate to constantly vibrate, and as a result, the levelness of the ueno may be impaired. Furthermore, since the carrier plate is rotated while being pressed by the elastic body, there is a problem in that the rotation of the upper shaft and the rotation of the carrier plate cannot completely respond. That is, due to frictional resistance on the polishing surface, twisting and return always occur between the upper shaft side top ring surface of the elastic hollow body and the carrier plate surface. This causes momentary stagnation and slippage of the tool against the polishing surface, which may lead to lack of levelness of the wafer and damage to the wafer, as described above. On the other hand, according to the pressing mechanism that balances the center and outer circumferential portions of the carrier plate mentioned in (■) above, the outer circumferential and central portions of the carrier plate are pressed against the slight curvature that occurs in the turntable. By doing so, a certain degree of parallelism between the polishing surface and the carrier plate can be ensured. However, the force applied to the wafer is applied to a portion of the carrier plate near the center and a portion of the outer circumference, that is, partial pressure is applied to the periphery of each wafer. Such partial pressure application to the carrier plate has a problem in that the horizontality of the wafer is disturbed because the pressure force does not apply uniformly to the entire surface of the wafer. The present invention was made in view of these problems, and
The purpose of this is to improve the flatness and smoothness of the wafer, especially the flatness, by making it follow the slight curvature of the turntable and evenly pressurizing the entire upper surface of the carrier plate. An object of the present invention is to provide an upper shaft mechanism for a polishing device.

[Means to solve the problem]

In order to solve the above problems, in the present invention, in order to polish the Noricon wafer bonded to the lower surface of the carrier plate, the upper surface of the carrier plate is polished on a revolving turntable via an upper shaft that rotates on its own axis. In an upper shaft mechanism of a polishing device that presses toward a surface, a pressure chamber is provided below the upper shaft between an upper plate fixed to the lower end of the upper shaft and a pressing plate that abuts the upper surface of the carrier plate. formed,
Further, the pressurizing chamber is provided with a pressing plate driving means that directly transmits the rotational force of the upper shaft to the pressing plate by a driving pin connected to the upper shaft or the upper plate. Characterize. Furthermore, in order to further deform the pressing plate in a complementary manner to the minute curvature of the turntable, the present invention is provided with an intermediate pressing shaft that can press the center of the upper surface of the pressing plate toward the carrier plate. It is characterized by being

[Effect]

A press plate is brought into contact with the upper surface of the carrier plate to which the wafer is adhered, and the carrier plate is pressed by the press plate. When the pressure chamber formed on the upper surface of the press plate is pressurized, the pressure within the pressurization chamber acts to push the press plate downward. The pressure inside the pressurizing chamber acts on almost the entire surface of the press plate,
Since the pressurizing chamber is expandable and swingable, it acts evenly on the entire upper surface of the carrier plate and presses the carrier plate toward the turntable. Even if the upper surface of the turntable is slightly distorted due to polishing heat, the carrier plate is evenly pressed to follow the distortion of the turntable. Further, since the pressing plate has normal rigidity, it stably holds the carrier plate. The drive pin, which is fixed to the upper shaft and rotates together with the upper shaft, directly transmits the rotational force of the upper shaft to the pressing plate. Furthermore, when the curvature of the turntable increases, the center of the press plate is pressurized by the intermediate press shaft in accordance with the polishing state of the wafer, and the parallelism between the carrier plate and the turntable is adjusted. maintain.

【Example】

An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, an upper shaft mechanism I is disposed above the turntable 8o of the Borinng apparatus, and below the upper shaft mechanism I, a wafer 82 to be polished is bonded to the lower surface of the carrier plate 8I. and placed on the turntable 8o. The upper shaft mechanism 1 includes an upper shaft 10 that applies pressure to the turntable 80 side while rotating, a hub wheel I5 that supports the upper shaft 1o and transmits rotational force to the upper shaft 10, and a housing 20 that supports these. The upper plate 3o and the pressing plate 4o are arranged below the upper shaft 1O and press the carrier plate 81. The upper shaft 10 is a hollow shaft, and is rotatably supported in the upper part by a bearing I2 attached to the inner cylinder of the upper housing 11, and is inserted and supported in the cylinder of the hub wheel 15 in the lower part. The hub wheel 15 and the upper shaft 10 are integrated with the hub pole I5, and the upper shaft 1O rotates.
The upper shaft 1O is coupled by slide bearings 17i and 17b so as to be able to slide up and down. Further, above the upper shaft 10, an upper shaft compressed air inlet 10a for introducing compressed air into the hollow portion 10b of the upper shaft 10 is provided. The upper housing 11 that supports the upper axis 1O is
An angular contact bearing is used for the bearing 12, which is a support part for supporting the upper shaft IO and at the same time raising and lowering it up and down, and is housed in the upper housing 11. In order to supply compressed air to the uniaxial compressed air inlet Oa, a compressed air inlet 11 is provided at one location in the upper housing.
iL is opened, and the compressed air introduction port 11a is connected at its rear end to a compressed air communication groove 11c cut along the inner circumference on the inner cylindrical surface of the housing 11 in contact with the outer surface of the upper shaft IO. There is. Thereby, the compressed air inlet 11λ is electrically connected to the hollow portion 10b of the upper shaft 10 via the upper shaft compressed air inlet lOa of the rotating upper shaft 10. Pressure air conduction groove 1
1c, the inner cylindrical surface of the upper housing 11 and the upper shaft 1
The outer peripheral surface of 0 is kept airtight by O-rings Ilb and Ilb. Second, the hub wheel 15 supporting the upper shaft 10 is
The housing 20 is rotatably supported in an insertion hole 201 by bearings 21a and 21b. The bearings 21a and 21b mounted here are attached to the outer circumference of the hub wheel 15,
They are fitted into the insertion holes 20a from above and below, respectively, and fixed by bearing stops 23 and 22. A sprocket 14 for giving rotation to the hub wheel 15 is fixed to the upper end of the hub wheel 15, and driving force from a drive motor (not shown) is transmitted through a drive chain 16. On the other hand, the upper shaft lO, which rotates together with the hub wheel 15,
The lower part is extended longer than the lower end of the hub wheel 15,
At its end, the diameter of the hollow portion 10b is slightly enlarged, and a flange portion IOC is provided which is widened like a brim. An upper plate 30 of a substantially circular flat plate is integrally attached to and suspended from the upper shaft 10 on the lower surface of the fledge portion 10c. In the present invention, the upper plate 3o is fixed to the lower end of the upper shaft 10, and further below the upper plate 30, a pressing plate 40 is arranged which contacts the upper surface of the carrier plate 81 placed on the turntable 80. In addition, a pressurizing chamber 5°a is formed between the upper plate 30 and the pressing plate 40, and inside this pressurizing chamber 5°a there is a drive connected to the upper shaft lO. It is characterized in that a driving means for the press plate 4o is provided for directly transmitting the rotational force of the upper shaft 10 to the press plate 4o using the pin 60. A bellows 50 is attached to the lower surface of the upper plate 3o fixed to the lower end of the upper shaft IO. The bellows 50 is formed into a bellows shape from an elastic material such as a thin stainless steel plate, and has a diameter close to the diameter of the pressing plate 4o. It is desirable that they have the same diameter or more. In the - direction, it has elasticity in the vertical direction in Figure 1.
The top and bottom surfaces are open. The lower surface of the bellows 5o is connected to the upper plate 3
The bellows 5 is fixed to one side of the pressing plate 40 which is a circular flat plate having almost the same shape as the bellows 5.
A space enclosed within the pressurizing chamber 50a is formed as a pressurizing chamber 50a. The upper plate 30 and the bellows 50, and the bellows 50 and the pressing plate 40 are each attached via a fixing plate 35.45 which is formed by a stepped process on one side of an annular flat plate, and the fixing plate 35.45 and the bellows The joint portion with 50 is kept airtight by welding. And Kokijoban 3
An upper plate pressure air conduit 30a communicating with the hollow portion 10b of the upper shaft 10 is formed in a substantially central portion of the upper housing I.
A compressed air path is configured from the compressed air inlet +1a of t to the pressurizing chamber 50&. Knob wheel 1 that transmits rotational force to the above-mentioned upper shaft 10
An annular drive pin support plate 18 is fixed to the lower end of the drive pin support plate 5, and a drive pin 60 for transmitting rotational force to the press plate 40 is integrally formed downward on the lower surface of the drive pin support plate 18. It is provided. In the drawing, the drive pin 60 extends downward from the drive pin support plate 18 fixed to the hub wheel 15 through the upper plate 30, or is fixed to the hub wheel 15, the upper shaft lO1, and the upper shaft lO. The purpose is to rotate together with the upper plate 30 and transmit the driving force to the pressing plate 40, and the upper shaft 1
0, and may be attached to the lower surface of the upper plate 30. Here, the upper plate 30 is attached to the flange portion 10c at the lower end of the upper shaft 10 due to the reinforcing structure of the portion, so that the upper plate 30 is penetrated and rotation is transmitted to the upper plate 30 at the same time. Also, drive pin 6
An O-ring 30b is attached to the drive pin insertion hole 36 of the upper plate 30 passing through the O-ring 30b to keep the pressurizing chamber 50a airtight. On the other hand, as shown in FIG. 2 (A-A horizontal sectional view in FIG. 1), two drive pins 60 are provided in two locations as a pair, and the drive pins 60 are provided at two locations on the press plate 40 in the pressurizing chamber 502L. A roller 62 for receiving the drive pin 60 is supported by a roller stay 61 on the upper surface. By receiving the drive pin with such a roller 62, rotational force is reliably transmitted to the pressing plate 40, and the carrier plate 8
The press plate 40 is slidably in contact with the vertical movement of the press plate 40 when the press plate 1 is attached or detached. In this embodiment, the driving means for the pressing plate 40 is a driving pin 60 and a roller 62, or has a vertically movable part, and transmits rotational force integral with the upper shaft 10. For example, a cylindrical outer body or the like into which the drive pin 60 is inserted may be provided on the upper surface of the pressing plate 40. Such an upper plate 30, bellows 50, and press plate 4
A side plate 31 is attached to the outer periphery of the pressurizing chamber 50a formed by the
．． 31 is integrally fixed to the periphery of the lower surface of the upper plate 30. As shown in FIGS. 2 and 3, the side plate 31 is divided into two parts over approximately 1/4 of the length of the periphery of the upper plate 30. As shown in FIGS. The lower end of the side plate 31 is suspended by the bellows 50 by supporting the periphery of the lower surface of the pressing plate 40 with bent parts 31a, 31a bent inward, and surrounding the pressing plate 40. This prevents the pressing plate 40 from shaking in the horizontal direction. Furthermore, the inner periphery of the end of the bent portion 31a is formed to match the outer periphery of the carrier plate 81, and when the pressing plate 40 is lowered, the side plate 31 allows the carrier plate 8I to be placed on the turntable 80. It is possible to position it. Furthermore, in the present invention, in order to deform the press plate 40 in a complementary manner to the minute curvature that occurs in the turntable 80, the center press shaft 70 which can be pressed so that the center of the upper surface of the press plate 40 is directed toward the carrier plate 81 is provided. It is characterized by being provided with. The intermediate push shaft 70 is inserted into the hollow portion 10b of the upper shaft 10, and is supported at one end by the upper end of the upper shaft 10. A rod 73 protrudes below the middle push shaft 70, and the upper plate 30
The other end of the intermediate push shaft 70 is supported by this penetrating portion. The intermediate push shaft 70 is inserted into the hollow portion lOb of the upper shaft 10 with a gap therebetween so as to form a compressed air path. The middle press shaft 70 and the upper shaft 1O keep the hollow part 10b airtight by the gasket 10d, and the upper shaft 1O slides and rotates. This middle push shaft 70 is a cylinder device 7 provided above the upper shaft IO! It is connected to
The lower rod 73 is pushed out by the cylinder device 71. An intermediate pressing member 72 is attached to the tip of the rod 73, which contacts the center of the press plate 40, and presses the center of the press plate 40 by operating a pressure control system connected to the cylinder device 71. ing. By the way, the drive pin support plate 1 is attached to the lower end of the hub wheel 15 and fixed to the drive pin 60 downward.
8 has ■ring 18a and bellows +8 on its outer periphery.
b is provided. Both of these prevent foreign matter such as abrasive grains from entering the bearing portion during polishing. (2) The ring 18a is in sliding contact with a bearing stop 22 attached to the back surface of the housing 20 to protect the bearing 21b. The glossy rose 18b provided to cover the lower part of the drive pin support plate 18 has its lower end fixed to the upper surface of the upper plate 30, and the lower end of the gloss rose 18b is fixed to the upper surface of the upper plate 30.
The slide bearing 17a expands and contracts in accordance with the vertical movement of the slide bearing 17a, thereby preventing foreign matter from entering the slide bearing 17a. Further, in this embodiment, a carrier plate peeling bar 25 is provided for peeling off the carrier plate 81 that is in close contact with the pressing plate 40 after polishing the wafer. This is because the carrier plate 81 is pressed by the pressing plate 40 during polishing, so the upper surface of the carrier plate 81 and the lower surface of the pressing plate 40 are in close contact with each other.
The carrier plate 81 is reliably peeled off when the upper shaft 10 starts to rise by preventing it from separating from the pressing plate 40 when the upper shaft 10 is rising, or from falling during or after the upper shaft 10 is rising. It is for. The carrier plate peeling bar 25 includes the upper plate 30 and the fixed plate 3.
5, 45, insertion holes 30c each formed in the pressing plate 40;
35c, 45c, and 40c. The head of the peeling bar 25 is molded into a flat plate, and the flat plate part and the upper plate 3
The spring 26 is inserted between the upper surface of the fixed plate 35 and the upper surface of the stone j
is installed in an adjustable position. A peeling ring 24, which is an annular body, is fixed to the lower surface of the tongue 20 so as to be concentric with the upper shaft 10. This peeling ring 24
The lower end and the head of the carrier plate peeling bar 25 are located at equal distances from the axis of the upper shaft 10 so as to touch each other on a plane. In the cross-sectional positional relationship between the peeling bar 25 and the peeling ring 24, during wafer polishing, the upper shaft 10 and the upper plate 3
Above this, the head of the peeling bar 25 and the peeling ring 24 are spaced apart from each other with a slight gap. Furthermore, during polishing, the peeling bar 25 is formed to a predetermined length so that its lower end does not protrude from the insertion hole 40c formed in the pressing plate 40.
It is adjusted by a stopper 27. Although some of the above-mentioned upper shaft mechanisms 1 are omitted from illustration, a plurality of units, usually four units, are installed somewhere above the turntable 80. The housing 20 is provided commonly to each upper shaft mechanism l, and is fixed to the main body of the apparatus. Above the housing 20, these upper shaft mechanisms 1゜1,...
A common drive motor is installed to simultaneously drive the upper shaft mechanisms 1, 1.・-1 sprocket +4.14. - The sequential drive is connected to a part of the drive chain 16 that goes around. Further, on the housing 20, there are provided an elevating cylinder device 85 for elevating and lowering the upper shaft IO, a fulcrum 87, and a connecting rod 86 that connects both. It is connected to the middle part of the connecting rod 86 at a fulcrum (not shown) attached to the upper housing 11 that supports the upper part of the upper shaft 10, and moves along with the upper housing 11 by the operation of the lifting nolinder device 85. upper shaft 10
can be raised and lowered. On the other hand, the compressed air inlet 11a of the upper housing 11 connected to the pressurizing chamber 50& formed below the upper shaft 1O is connected to a conduit 74a connected to the upstream pressure regulator 73a,
The pressure in the pressurizing chamber 50 is adjusted. Further, a norinda device 71 for operating the rod 73 of the intermediate push shaft 70 is connected to a conduit 74b with a pressure regulator 73b interposed therebetween. A positioning device is provided at the center of the housing 20 so as to match and abut a part of the outer periphery of the carrier plate 81 and to simultaneously position a plurality of carrier plates 81 on the turntable. This positioning device connects the bottom surface of the no\unnog 20 and the turntable 8.
It is attached so that it can be raised and lowered between it and the upper surface of 0 by means of a Norinda device. Also, one thing omitted in the above explanation is,
A circular arc notch slightly smaller than the outer circumference of the carrier plate 81 is provided at the peripheral edge portion of the upper plate 30 to which the side plate 31 is not fixed, so that the positioning device on the lower surface of the tongue 20 can reach the upper surface of the turntable. By descending, the carrier plate 81 can be initially positioned. Next, the operation of the upper shaft mechanism 1 having such a configuration will be explained. A polishing cloth (not shown) is attached to the top surface of the turntable 80 in advance, and the wafer 8 to be polished is placed on the polishing cloth.
The two bonded carrier plates 81 are placed in a predetermined position using the positioning device described above, with the polished surface of the wafer 82 facing downward. Next, when the upper shaft mechanism 1 starts operating, the cylinder device 85 causes the upper housing 1 to
1 is pushed down, and along with this, the upper shaft 10, the upper plate 30,
Then, the press plate 40, which is integrated with the pressure chamber 50a, is lowered. Since the carrier plate 81 is positioned in advance, the bent portion 31a is fixed to the periphery of the upper plate 30 and provided at the lower end of the side plate 31. It is fitted into the inner periphery of 31a and abuts against the lower surface of press plate 40. Then, the upper shaft 10 descends until the press plate 40 is slightly lifted by the carrier plate 81. The lifting cylinder device 85 is held in this state until the polishing is completed. When the upper shaft 10 descends, the
Since the knob wheel 15 is supported on the housing 20 side, the drive pin 6 connected below the knob wheel 15
0, the roller 62 slides downward. and,
The pressure chamber 502L is kept under pressure by the pressure regulator 73a so as to maintain a predetermined pressure during polishing. From this state, the turntable 80 rotates to perform polishing, but at the same time as the turntable 80 starts,
The drive motor also starts rotating independently, and the rotation is transmitted to the sprocket 14 by a drive chain 16 connected to the drive motor. When the knob wheel 15 to which the sprocket 14 is fixed rotates, the slide hair ring 17a. The upper shaft IO whose slippage in the rotational direction is regulated by 17b starts rotating integrally with the hub wheel 15. The upper plate 30, the bellows 50, and the press plate 40 rotate together with the upper shaft IO, or in particular, the rotation force is transmitted to the press plate 40 by the driving pin 60. Alkaline Norikasol is dropped onto the polishing surface to advance the polishing of the wafer 82, or the pressure in the pressurizing chamber 50a is adjusted depending on the polishing state of the wafer 82. moreover,
Normally, due to heat generation, a slight curvature with the bottom at the center of the turntable 80 occurs, but in cases where the turntable 80 is severely distorted during polishing and the finished state of the wafer 82 lacks flatness. This can be corrected by applying pressure to the center of the upper surface of the pressing plate 40 using the cylinder device 71 of the intermediate pressing shaft 70. When polishing is completed, the rotation of the turntable 80, the upper shaft 1O, etc. is stopped, and the upper shaft is moved by the lifting cylinder device 85, contrary to the initial state.

0 is lifted and the carrier plate 8I is separated from the turntable 80. At this time, as shown in FIG. 3, the carrier plate 81 is peeled off from the press plate 40 by the carrier plate peeling bar 25. The peeling bar 25 is pulled up by the spring 26 when the upper shaft 10 is lowered and the pressing plate 40 is in contact with the carrier plate 81, as shown in FIG. 40 does not protrude from the lower surface of the insertion hole 40c. The head of the peeling bar 25 and the peeling ring 24 on the lower surface of the housing 20 are separated from each other. Next, after finishing the polishing, the upper shaft 10
As it rises, the head of the peeling bar 25 comes into contact with the lower end of the peeling ring 24, and as it rises further, the
This peeling ring 24 serves as a stop for the peeling bar 25 and pushes down the peeling bar 25 relative to the pressing plate 40, so that the lower end of the peeling bar 25 protrudes from the insertion hole 40c of the pressing plate 40. Therefore, when the upper shaft 10 starts to rise, the carrier plate 81 can be safely turned and peeled off onto the table 80. Next, the operation of the upper shaft mechanism 1 of the present invention will be explained. A carrier plate 81 with a wafer 82 adhered to the bottom surface
The carrier plate 81 is pressed by the pressing plate 40 that is in contact with the upper surface of the carrier plate 81 . The inside of the pressurizing chamber 50a formed including the upper surface of the pressing plate 40 is
b, and when pressurized through the upper plate pressure air conduit 30a,
Since the bellows 50 is attached to expand and contract in the vertical direction, the pressure within the pressurizing chamber 50a acts to push the press plate 40 downward. The pressure of the pressurizing chamber 50+L acts directly on almost the entire top surface of the pressing plate 40, and since the pressurizing chamber 50a formed by the bellows 50 can expand and contract freely, it acts evenly on the entire top surface of the carrier plate 81. and press the carrier plate 81 toward the turntable 80. Due to the heat generated during polishing, slight distortion occurs on the top surface of the turntable 80, but since the pressing plate 40 presses the carrier plate 81 evenly as described above,
The carrier plate 8I is made to follow the distortion of the turntable 80. Second, since the press plate 40 has normal rigidity, it stably holds the carrier plate 81 and prevents the carrier plate 81 from swinging due to distortion of the polished surface or foreign matter. The drive pin 60 fixed to the hub wheel 15, which rotates together with the upper shaft lO, directly propagates the rotational force on the upper shaft side to the pressing plate 40, causing the pressing plate 40 to rotate integrally with the upper shaft lO. let Furthermore, when the distortion generated in the turntable 80 increases and the curvature progresses, the rod 7 of the intermediate push shaft 70 located at the axial center of the upper shaft 10 corresponds to the polishing state of the wafer 82.
3, the center of the press plate 40 is pressurized in a complementary manner to maintain the parallelism between the carrier plate 81 and the turntable 80. In this case as well, the press plate 40 has a pressurizing chamber 5.
The pressure of 0.02L is applied evenly, causing the carrier plate 81 to follow the upper surface of the turntable 80. [Effects] Since the present invention is configured as described above, it produces the effects described below. ■ Pressure is applied to almost the entire area of the upper surface of the pressing plate included in the pressurizing chamber that is provided below the upper shaft and can freely swing. Since the pressure can be applied evenly and the polishing surface of the turntable can be followed, the flatness of the wafer to be polished can be improved. ■ Since the pressing plate that presses the carrier plate on the lower surface of the pressurizing chamber is a flat plate, the carrier plate does not swing during rotational polishing and can be held stably. ■ Since the rotational force to the press plate is directly transmitted from the upper shaft, the carrier plate can be rotated stably, and there is no momentary stagnation or slippage on the polishing surface, improving the flatness and smoothness of the wafer. can. - Since the parallelism of the carrier plate can be corrected using the intermediate push shaft in accordance with the degree of curvature of the turntable, the flatness of the wafer can be ensured regardless of the state of polishing heat accumulation, and continuous work is also possible.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the upper shaft mechanism of the present invention, Fig. 2 is an A-A horizontal sectional view showing the drive pin and side plate, and Fig. 3 (a).
FIG. 4 and FIG. 5 are cross-sectional views showing a conventional example. ■・・・Top shaft mechanism, IO：Top shaft, 10a：Top compressed air inlet, It：Top housing, I4：Sprocket , 15...Hub wheel, +7a, 17b...Slide bearing, 20...
...Housing, 21a, 21b...Bearing, 24 Peeling link, 25...Carrier plate peeling bar, 30...Top plate 30a, Top plate compressed air conduit, 31...Side plate, 40...Press plate 50...Heroes, 50a...Pressure chamber, 60...Drive pin, 62...Roller, 70...Medium push shaft, 73... Loft, 80... Turntable, 81... Carrier plate, 82... Wafer, 85... Lifting cylinder device.

Claims (2)

[Claims] (1) In order to polish the silicon wafer bonded to the bottom surface of the carrier plate, a polishing device that presses the top surface of the carrier plate toward the polishing surface on a revolving turntable via an upper shaft that rotates on its own axis. In the shaft mechanism, a pressurizing chamber is formed below the upper shaft between an upper plate fixed to the lower end of the upper shaft and a pressing plate abutting the upper surface of the carrier plate, and a pressurizing chamber is formed in the pressurizing chamber. The upper shaft of a polishing apparatus is characterized in that a pressing plate driving means is provided for directly transmitting the rotational force of the upper shaft to the pressing plate by a driving pin connected to the upper shaft or the upper plate. mechanism. (2) The upper shaft mechanism of the polishing apparatus according to claim 1, further comprising an intermediate push shaft that can push the center of the upper surface of the press plate toward the carrier plate.