JPH06198561A - Polishing apparatus - Google Patents

Abstract

PURPOSE:To provide a polishing apparatus in which a top ring main body can follow up the movement (tilting) of the top surface of a turn table smoothly and quickly and the rotational torque of a top ring driving shaft can be surely transmitted to the top ring main body. CONSTITUTION:A polishing apparatus comprises a turn table 20 and a top ring main body 3 which are respectively rotated with independent rotational frequencies and have top surface where abrasive cloth is stretched, wherein a material 6 to be polished is interposed between the turn table 20 and the top ring main body 3. The polishing apparatus is provided with a top ring driving shaft 1 connected to a driving device 13 connected to a pressing device 12 for pressing the top ring main body 3 for driving in rotation the top ring main body 3. A ball bearing 2 is interposed between the top ring driving shaft 1 and the top ring main body 3, whereby the lower surface of the top ring main body 3 can follow up the movement of the top surface of the turn table 20 smoothly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus, and more particularly to a polishing apparatus for polishing a polishing object such as a semiconductor wafer into a flat and mirror surface.

[0002]

2. Description of the Related Art In recent years, as the degree of integration of semiconductor devices has increased, circuit wiring has become finer and the distance between wirings has become smaller. In particular, in the case of optical lithography of 0.5 μm or less, the depth of focus becomes shallow, so that the flatness of the image plane of the stepper is required. Therefore, it is necessary to flatten the surface of the semiconductor wafer. As one means of this flattening method, polishing is performed by a polishing device.

Conventionally, this type of polishing apparatus has a turntable and a top ring that rotate independently of each other, and the top ring applies a constant pressure to the turntable so that the space between the turntable and the top ring is increased. The surface of the object to be polished is flattened and mirror-finished with the object to be polished interposed therebetween.

As the above-mentioned type of polishing apparatus, for example, Japanese Patent Laid-Open Nos. 2-278822 and 4-1.
There is a device described in No. 9065. JP-A-2-278
In the device described in No. 822, a spherical surface 82 is integrally formed at the tip of the drive shaft 81 as shown in FIG.
4, the top ring main body 84 smoothly follows the movement (tilt) of the turntable surface.

In the apparatus disclosed in Japanese Patent Laid-Open No. 4-19065, a member 92 having a spherical surface 92a is integrally fixed to the tip of a drive shaft 91 as shown in FIG. The spherical seat 93 that accommodates the top ring body 94 is fixed to the top ring body 94 so that the top ring body 94 can smoothly follow the movement (tilt) of the turntable surface.

[0006]

[Problems to be Solved by the Invention] FIG. 17 (a) and FIG.
In the conventional device shown in FIG. 8 (a), the top ring main bodies 84, 94 are tiltable as shown by arrow A around the spherical surface as shown in the schematic views of FIGS. 17 (b) and 18 (b). In addition, the top ring bodies 84 and 94 are rotatable about the axes thereof as indicated by arrow B. That is, the top ring body is capable of following the turntable surface and performing a single movement indicated by arrows A and B and a combined movement thereof.

However, when the top ring bodies 84 and 94 in the polishing portion having the above-mentioned structure are pressed against the turntable surface 95 inclined by α ° by the pressing force F as shown in FIG. 19, the top ring body is spherical. It is necessary to move by the arc length L with respect to. When the inclination of the turntable surface is small, the time required for the top ring body to move by the arc length L is small, but when the inclination of the turntable surface is locally large, the arc length that the top ring body moves There is a problem that L becomes long and the time required to move the top ring body becomes long, which deteriorates the followability of the top ring body.

The present invention has been made in view of the above circumstances, and the top ring body can smoothly and quickly follow the movement (tilt) of the upper surface of the turntable, and the rotation torque of the top ring drive shaft can be reliably ensured. It is an object to provide a polishing device that is transmitted to a main body.

[0009]

In order to achieve the above-mentioned object, a polishing apparatus of the present invention has a turntable and a top ring body each having an upper surface which is rotated at an independent number of revolutions, and a polishing table is covered with a polishing cloth. In a polishing device that polishes the surface of the polishing target object to be flat and mirror-finished by pressing the polishing target object with a predetermined force between the turntable and the top ring main body, pressing the top ring main body. A top ring drive shaft connected to a pressing device for rotating and driving the top ring body, and a ball bearing is provided between the top ring drive shaft and the top ring body. It has a special feature that the lower surface of the top ring body can smoothly follow the movement of the turntable surface. It is an.

The top ring body is provided with a plurality of suction holes that are open to the lower surface of the top ring body and communicate with a vacuum source.

The mechanism for transmitting the drive from the top ring drive shaft to the top ring body is composed of a torque transmission pin provided on the top ring drive shaft and a torque transmission pin provided on the top ring body. It is characterized in that the rotational force of the ring drive shaft is transmitted to the top ring body.

Further, the torque transmission pin provided on the top ring drive shaft is provided with a shock absorbing material made of an elastic body for absorbing vibration, and both drive pins are brought into contact with each other via the shock absorbing material.

Further, the radial bearing for rotatably supporting the top ring drive shaft is fixed to the fixed side via a shock absorbing means (O ring or shock absorbing mechanism) for absorbing vibration.

Further, the provision of surface pressure adjusting means for adjusting the surface pressure distribution on the lower surface of the top ring body (for example, in FIG. 10, this is performed by changing the diameters D and d / D with respect to the diameter d). Characterize.

Further, the polishing apparatus is provided with a polishing object delivery mechanism for delivering the polishing object to or from the top ring, and the polishing object delivery mechanism places the polishing object on the top and moves it up and down. It is possible to provide the polishing target object to the vacuum suction part on the lower surface of the top ring body or to provide the polishing target object to receive the polishing target object from the vacuum suction part, and the mounting part transfers the polishing target object. When the polishing is performed, it is supported by a cushioning mechanism so as not to give an impact force to the polishing object.

[0016]

According to the present invention having the above-described structure, since the top ring is divided into three parts, the top ring drive shaft, the ball bearing, and the top ring body, the degree of freedom of the top ring body is increased, and the top ring body is The turntable surface can be swung quickly to follow the turntable surface, and the surface of an object to be polished such as a semiconductor wafer can be precisely flattened and mirror-polished. Since it rotates in synchronization with the rotation of the ring drive shaft, the grade of flat and mirror-finished is stable.

Further, since the top ring main body and the top ring drive shaft rotate in synchronization, a vacuum hole is introduced to the center of the top ring to draw a vacuum, and a vacuum provided in the center of the top ring drive shaft. Since the holes do not coincide with the holes, the vacuum line of the top ring can be freely designed.

Further, by providing the torque transmission pin with a shock absorbing material made of an elastic body for absorbing the vibration so that the torque transmission pin and the torque transmission pin come into contact with each other through the shock absorbing material, the vibration of the top ring drive shaft is Since it is absorbed by the cushioning material, the vibration is not transmitted to the top ring body.

Further, since the radial bearing for supporting the top ring drive shaft is fixed to the fixed side via the shock absorbing means for absorbing the vibration, the vibration of the top ring drive shaft is absorbed by the shock absorbing means, and the top ring is absorbed. It is not transmitted to the body.

Further, by providing the surface pressure control means for controlling the surface pressure distribution on the lower surface of the top ring body, the surface pressure distribution on the lower surface of the top ring body can be made uniform and uniform polishing can be achieved. It will be possible.

Further, the polishing object delivery mechanism is provided with a cushioning mechanism so as not to give an impact force to the polishing object when the polishing object is delivered to or from the top ring body. Even if a cylinder with a large diameter is used to move up and down, fine pressure adjustment is not necessary, damage to the polishing object is not caused, and it is necessary to perform delicate sensor adjustment of the delivery position of the polishing object. Absent.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the polishing apparatus according to the present invention will be described below with reference to FIGS. 1 and 2
FIG. 1 is a view showing a polishing portion of a semiconductor wafer polishing apparatus of the present invention, FIG. 1 is a vertical sectional view, and FIG. 2 is a plan view. The top ring portion of the polishing apparatus is composed of a top ring drive shaft 1, a top ring body 3, and a ball bearing 2 interposed between the top ring drive shaft 1 and the top ring body 3.

At the center of the lower end surface of the top ring drive shaft 1, a concave spherical surface 1a with which a ball bearing 2 is in sliding contact is formed. Top ring body 3 is top ring body top 3
-1 and the top ring body lower part 3-2. A concave spherical surface 3-1a with which the ball bearing 2 is in sliding contact is formed in the center of the upper surface of the top ring body upper portion 3-1, and a wafer locking ring 5 is attached to the outer periphery of the top ring body lower portion 3-2. .

A large number of vacuum suction holes 3-2a are formed in the lower surface of the top ring body 3-2 and open to the lower surface. A vacuum groove 3-1b communicating with the vacuum suction hole 3-2a is formed in the top ring body upper portion 3-1.
1b communicates with four vacuum holes 3-1c formed in the top ring body upper portion 3-1. The vacuum hole 3-1c is communicated with the vacuum line tube 10, the tube joint 9 and the tube joint 11 to the vacuum hole 1b provided at the center of the top ring drive shaft 1.

The top ring drive shaft 1 is integrally provided with a flange portion 1c, and four torque transmission pins 7 are provided on the outer periphery of the flange portion 1c. Further, four torque transmission pins 8 are provided on the upper surface of the top ring body upper portion 3-1 of the top ring body 3 in correspondence with the torque transmission pins 7. The semiconductor wafer 6 is housed in a space surrounded by the lower surface of the lower portion 3-2 of the top ring main body, the inner periphery of the wafer outer ring 5 and the upper surface of the turntable (not shown), and the turntable is rotated and the top ring is rotated. While rotating the drive shaft 1 and transmitting the rotational torque to the top ring body 3 by the engagement of the torque transmission pin 7 and the torque transmission pin 8, the top ring body 3 is rotated and the top ring body 3 is slid. The surface of the semiconductor wafer 6 is polished to be flat and mirror-finished.

A top ring holder 4 is provided above the flange portion 1c of the top ring drive shaft 1, and the top ring holder 4 is connected to the top ring body 3 by bolts 41. A spring 42 is interposed between the bolt 41 and the top ring holder 4. When the top ring drive shaft 1 is raised, the top ring holder 4 rises together with the top ring body 3. In this raised state, the spring 42 is soft and has the function of keeping the top ring body 3 horizontal. The function of keeping the top ring body 3 soft and horizontal effectively works when the semiconductor wafer 6 is transferred.

FIG. 3 is a diagram showing the overall construction of a polishing apparatus using the polishing section shown in FIGS. 1 and 2.
In FIG. 3, reference numeral 20 is a turntable, and the turntable 20 can rotate about a shaft 21. A turntable ring 22 is provided on the outer peripheral portion of the turntable 20 to prevent the polishing abrasive liquid and the like from scattering. Further, the polishing cloth 2 is provided on the upper surface of the turntable 20.
3 is stretched.

On the upper portion of the turntable 20, the top ring portion constructed as described above is arranged. A top ring cylinder 12 is provided above the top ring drive shaft 1, and the top ring body 12 is pressed by the top ring cylinder 12 against the turntable 20 with a constant pressure. Reference numeral 13 is a top ring drive motor, which applies rotational torque to the top ring drive shaft 1 via the gear 14, the gear 15, and the gear 16. Further, a polishing / polishing liquid nozzle 17 is installed above the turntable 20.
The polishing abrasive liquid Q can be jetted onto the polishing cloth 23 of 0.

In the polishing apparatus having the above structure, the semiconductor wafer 6 is attached to the lower surface of the lower portion 3-2 of the top ring body by vacuum suction, and the polishing cloth 23 on the upper surface of the turntable 20.
The top ring cylinder 12 applies pressure to the top to apply pressure. At this time, the turntable 20 starts rotating. Next, by flowing the polishing abrasive liquid Q from the polishing abrasive liquid nozzle 17 onto the polishing cloth 23, the polishing abrasive liquid Q is held on the polishing cloth 23 and the polishing abrasive liquid Q is applied to the surface (lower surface) of the semiconductor wafer 6 to be polished. Enters and begins polishing.

At this time, even if the top surface of the turntable 20 has a slight inclination, the top ring body 3 is swung quickly with respect to the top ring drive shaft 1 by the ball bearing 2. Even if the top ring body 3 is tilted, the torque transmission pin 7 on the top ring drive shaft 1 side
Since the torque transmission pin 8 on the top ring body 3 side is in point contact, the contact point is shifted in each case to reliably transmit the rotational torque of the top ring drive shaft 1 to the top ring body 3.

FIG. 4 is an explanatory diagram for explaining the operation of the polishing section in the polishing apparatus. As shown in FIG. 4A, the polishing portion has a top ring drive shaft 1, a ball bearing 2, and a top ring body 3 which are divided into three parts. The ball bearing 2 is made of ceramics, and the sliding contact portion of the top ring drive shaft 1 and the ball bearing 2 of the top ring body 3 is made of stainless steel. Therefore, as shown in the schematic view of FIG. 4 (b), the top ring body 3 has an arrow A in the rotation of the ball bearing 2.
In addition, the top ring main body 3 can be tilted as shown by, and can be rotated as shown by arrow B around the axis of the top ring body 3.
The ball bearing 2 can rotate around the center of the ball bearing 2 as shown by arrow C. That is, since the ball bearing 2 capable of freely moving is interposed between the top ring body 3 and the top ring drive shaft 1, the degree of freedom is increased as compared with the conventional example, and the top ring body 3
Is capable of following the turntable surface and performing a single movement indicated by arrows A, B and C and a combined movement thereof.

However, when the top ring body 3 in the polishing portion having the above-mentioned structure is pressed against the turntable surface 20 inclined by α ° by the pressing force F as shown in FIG. 4C, the top ring body 3 is pressed. Is a ball bearing 2
It is necessary to apparently move by an arc length L with respect to the spherical surface. However, since the spherical surface of the ball bearing 2 also has a degree of freedom, if the ball bearing 2 moves the arc length L / 2 with respect to the top ring drive shaft 1 and the top ring body 3 moves the arc length L / 2 with respect to the ball bearing 2. , Which is equivalent to the top ring body 3 being inclined by α °.

In the present invention, the top ring body 3 and the top ring drive shaft 1 are made of the same material and have the same coefficient of friction with respect to the ball bearing 2. Therefore, the top ring body 3 moves by the arc length L. While the ball bearing 2 is moving, the ball bearing 2 moves in the arc length L / 2 with respect to the top ring drive shaft 1, and the top ring body 3 moves L / 2 with respect to the ball bearing 2. At this time, the time required for L / 2 movement can be 1/2 the time required for L movement, so that FIG. 17 and FIG.
Compared with the conventional example shown in FIG.
There is a merit that you can quickly follow in 1/2 time.

When the top ring body 3 is pressed against the polishing cloth 23 via the semiconductor wafer 6, the wafer 6
Vibration is generated by the coefficient of friction between the polishing cloth and the polishing cloth.
In particular, at the beginning of rotation, the coefficient of friction shifts from the coefficient of static friction to the coefficient of dynamic friction, causing a stick-slip phenomenon.
Rotational unevenness easily occurs and vibration is likely to occur. 17 and 1
When the conventional example shown in FIG. 8 is compared with the polishing portion of the present invention, vibration particularly in the rotational direction is transmitted from the top ring body directly to the top ring drive shaft in the conventional example.

In the case of the present invention, it is transmitted from the top ring body 3 to the ball bearing 2 and then to the top ring drive shaft 1. In this case, since the polishing portion of the present invention has the divided structure, the ball bearing 2 has a degree of freedom in the rotation direction, and thus vibration in the rotation direction is less likely to be transmitted to the top ring drive shaft 1.

FIG. 5 is a vertical sectional view showing another structure of the polishing portion of the polishing apparatus of the present invention. As shown in the figure, in the polishing portion, the top ring main body 3 is not provided with a vacuum suction hole opening on the lower surface thereof, and the top ring drive shaft 1 is not provided with a vacuum hole communicating therewith. That is, the top ring body 3 does not have a function of adsorbing the semiconductor wafer 6 on its lower surface. Other configurations are the same as those of the polishing section shown in FIGS. 1 and 2. Thus, even if the top ring body 3 does not have a vacuum suction function, there is no problem in polishing the surface of the semiconductor wafer 6 to be flat and mirror-finished.

When the surface of the semiconductor wafer is flat and mirror-polished with the polishing apparatus of the present invention, the so-called edge phenomenon in which the edge of the semiconductor wafer is excessively polished is extremely small. The reason for this is that by supporting the top ring body 3 on the lower end of the top ring drive shaft 1 via the ball bearing 2 as described above,
6, the stress is generated toward the center O of the ball bearing 2, and the magnitude becomes weaker as it goes away from the center O. If the rigidity of the top ring body 3 is set appropriately, The part of the ring body 3 away from the center is deformed upward as shown by the chain line, and the pressure applied to the semiconductor wafer 6 at this part is weakened, so that the edge of the semiconductor wafer 6 is excessively polished. It can be inferred that it will disappear.

Next, another embodiment of the polishing apparatus of the present invention is shown in FIGS. In the embodiment shown in FIGS. 1 and 2, since the torque transmission pin 7 on the top ring drive shaft 1 side and the torque transmission pin 8 on the top ring main body 3 side are in direct contact with each other, the vibration of the top ring drive shaft 1 is It may be directly transmitted to the top ring body 3 and may adversely affect uniform polishing, that is, polishing. Therefore, as shown in FIGS. 7 and 8, the outer periphery of the torque transmission pin 7 is covered with a cushioning material 31 made of an elastic material such as a rubber material,
The torque transmission pin 8 and the torque transmission pin 8 are in contact with each other via the cushioning material 31. As a result, the vibration of the top ring drive shaft 1 is absorbed by the cushioning material 31 and is not transmitted to the top ring body 3. The cushioning material 31 may be provided on the outer circumference of the torque transmission pin 8 or may be provided on both the torque transmission pin 7 and the torque transmission pin 8.

In order to more completely absorb the vibration of the top ring drive shaft 1, as shown in FIG. 7, an O-ring 32 is provided between the radial bearing 33 supporting the top ring drive shaft 1 and the fixed side 35. A buffer means is provided. As a result, the vibration of the top ring drive shaft 1 is absorbed by this cushioning means, and the vibration is suppressed. Further, as this buffering means, as shown in FIG. 9, the radial bearing 33 and the fixed side 3 are provided.
Two O-rings 32-1 with a predetermined space between them,
32-2 is provided, and oil R is supplied from the oil sump 36 between the O-rings 32-1 and 32-2 to configure a buffer mechanism 34. The buffer mechanism 34 prevents vibration of the top ring drive shaft 1. You may make it absorb. Further, the cushioning means of the O-ring 32 and the cushioning mechanism 34 do not necessarily have to be provided between the radial bearing 33 and the fixed side 35, but may be provided between the top ring drive shaft 1 and the radial bearing 33.

In order to perform polishing uniformly, it is necessary to make the surface pressure distribution on the lower surface of the top ring body 3 against the turntable 20 uniform. FIG. 10 is a view showing an example of a surface pressure adjusting means for making the surface pressure distribution on the lower surface of the top ring body 3 uniform. The present surface pressure adjusting means comprises a surface pressure adjusting member 37 provided between the upper surface of the top ring body 3 and the ball bearing 2. The surface pressure adjusting member 37 is disk-shaped and has a circular convex portion 37a at the center of the upper surface and a ring-shaped convex portion 37b at the outer peripheral portion of the lower surface. Convex portion 37a
A concave portion into which the ball bearing 2 is inserted is formed in the central portion of, and the lower end surface of the ring-shaped convex portion 37b contacts the upper surface of the top ring body 3. Here, by appropriately changing the area of the surface where the convex portion 37b contacts the top ring body 3,
The surface pressure distribution on the lower surface of the top ring body 3 can be adjusted. That is, in FIG. 10, the inner diameter d of the convex portion 37b,
By changing the ratio d / D of the outer diameter D, the surface pressure distribution on the lower surface of the top ring body 3 can be adjusted. Note that in FIG. 10, the surface pressure distribution on the lower surface of the top ring body 3 can be adjusted by setting d = 0 and appropriately changing D.

The surface pressure adjusting means is not limited to the example shown in FIG. 10, and for example, the surface pressure adjusting member 37.
It goes without saying that a means for applying an evenly distributed load, such as an air bag, may be provided between the lower surface of the above and the upper surface of the top ring body 3.

The embodiment shown in FIGS. 1 and 2, FIGS. 7 and 8
In the embodiment shown in (1), a vacuum hole is formed in the top ring body 3 in order to attract the semiconductor wafer 6 to the top ring body 3. 11 to 13 are views showing various configurations of the vacuum holes formed in the top ring body 3. In FIG. 11, a vacuum suction hole 3c is formed in the integrally formed top ring body 3. The vacuum hole 3c has a thin tip (0.5 to 1.0 mm) and is opened on the lower surface of the top ring body 3. Further, in FIG. 12, a vacuum suction hole 3-2a with a thin tip opening is formed on the lower surface of the top ring body lower portion 3-2, and the top ring body upper portion 3-1 communicates with the vacuum suction hole 3-2a. Vacuum groove 3-1b is formed, and the vacuum groove 3-1b communicates with four vacuum holes 3-1c also formed in the top ring body upper portion 3-1. Further, in FIG. 13, the top ring body 3 has a structure in which a top ring plate 3-2'a made of a porous ceramic material having a large number of holes is fitted inside a ring-shaped lower portion of the top ring body 3-2 '. The top ring body upper part 3-1 is formed with a vacuum groove 3-1b communicating with a large number of holes of the top ring plate 3-2'a. The vacuum groove 3-1b is formed on the top ring body upper part 3-1. To the four vacuum holes 3-1c formed in the above.

Next, a polishing object delivery mechanism for delivering a semiconductor wafer to or from the top ring of the polishing apparatus, which is installed in the polishing apparatus, will be described with reference to FIGS. 14 to 16. FIG. 14 is a view showing the structure of the polishing object delivery mechanism 66 of the present invention. In FIG. 14, reference numeral 51 denotes a disk-shaped base, a plurality of suction pieces 52 are attached to the upper part of the peripheral end of the base 51, and the suction pad 5 is further provided on the suction piece 52.
3 is attached. Further, vacuum holes 52a and 53a communicating with each other are formed in the respective central portions of the suction piece 52 and the suction pad 53, and the vacuum holes 52a and 53a are connected to a vacuum line tube 55 via a vacuum joint 54.
Is in communication with.

The base 51 is fixed to the upper end of a shaft 56, and the shaft 56 is supported by a bearing 58 through a bearing sleeve 57 with a flange so as to be vertically slidable. Reference numeral 60
Is a spring, and the spring 60 is sandwiched between the step portion formed on the shaft 56 and the spring pressing portion 59,
Gives an elastic force that pushes up. A male screw is formed on the outer circumference of the spring retainer 59, and the spring retainer 59 is screwed into a female screw formed at the center of the bearing 58. Reference numeral 62 is a nut screwed to the tip of the shaft 56, and when the nut 62 abuts the stopper 61,
The pushing up of the shaft 56 by the spring 60 is stopped at this position.

The bearing 58 is fixed to the tip of an arm 63, and the arm 63 can be moved up and down by an elevator as shown by an arrow Z. In the polishing object delivery mechanism 66 having the above-mentioned configuration, the suction pad 5
The semiconductor wafer 6 is mounted on the upper part of the semiconductor wafer 3. When the vacuum line tube 55 is connected to a vacuum source, the semiconductor wafer 6 is vacuum-sucked on the suction pad 53. In addition, the base 5 is attached via the suction pad 53 and the suction piece 52.
When a pressure such as an impact is applied to 1, the shaft 56 descends against the elastic force of the spring 60. That is, the bearing sleeve 57, the bearing 58, the spring pressing portion 59, and the spring 60 constitute a buffer mechanism that buffers pressure such as impact applied to the base. Incidentally, reference numeral 51a is a suction piece 52 and a base 51.
It is an O-ring for keeping the vacuum tightness between and.

FIG. 15 is a view showing a state in which the polishing object delivery mechanism 66 having the above structure is used to deliver the polishing object to or from the top ring of the polishing apparatus. Since the polishing section has the same structure as that of the embodiment shown in FIGS. 1 and 2, the description thereof will be omitted.

When the top ring drive shaft 1 is raised, the top ring holder 4 rises together with the top ring body 3. In this raised state, the spring 41 is soft and has a function of keeping the top ring body 3 horizontal. And this function works effectively especially when the semiconductor wafer 6 is delivered.

When the semiconductor wafer 6 is attracted to the lower surface of the top ring body 3 of the polishing portion, the vacuum hole 1b provided at the central portion of the top ring drive shaft 1 is connected to a vacuum source, so that the top ring body lower portion 3 -2 is sucked through the vacuum suction hole 3-2a. In this state, the semiconductor wafer 6 is placed on the suction pad 53 of the suction piece 52 of the polishing object transfer mechanism 66, and the semiconductor wafer 6
Is pushed up toward the lower surface of the top ring body 3 by the elevator 64 via the arm 63 and the base 51. When reaching the top ring body 3, the semiconductor wafer 6 is vacuum-adsorbed on the lower surface of the top ring body 3.

At this time, the base 51 receives a downward pressing force, but this pressing force is absorbed by the shaft 56 descending against the elastic force of the spring 60, so this pressing force is applied. Is not a shock to. When the semiconductor wafer 6 is received from the top ring body 3, the suction piece 52 of the polishing object transfer mechanism 66.
A suction pad 53 of
The vacuum hole 1b is removed from the vacuum source, and the vacuum line tube 55
Is connected to a vacuum source, the semiconductor wafer 6 is sucked onto the suction pad 53. At this time, when the suction pad 53 is brought into contact with the lower surface of the semiconductor wafer 6, the base 51 receives a downward pressing force, which is caused by the shaft 56 descending against the elastic force of the spring 60. Absorbed,
It does not give an impact to the semiconductor wafer 6.

Further, by providing the polishing object delivery mechanism 66 with the buffer mechanism composed of the spring 60 and the like in this way, even when a stepping motor is used as the drive motor of the elevator 64, the stepping motor does not cause a step-out phenomenon. In the above embodiment, the cushioning mechanism using the elastic force of the spring 60 is used. However, the cushioning mechanism is not limited to this, and absorbs pressure such as impact applied to the semiconductor wafer when the semiconductor wafer is transferred. Then
Any structure may be used as long as it does not damage the semiconductor wafer.

FIG. 16 is a schematic diagram showing the overall structure of an apparatus for polishing and cleaning a semiconductor wafer. The polishing object delivery mechanism 66 is arranged on the load side of the semiconductor wafer, and the polishing object delivery mechanism 6 is placed on the unload side.
6 and the cleaning unit 70 are arranged, and the turntable 20 is arranged in the middle thereof. As the elevator 64 rises, the semiconductor wafer 6 placed on the polishing object transfer mechanism 66 is attracted to the lower surface of the top ring body 3.
The turntable 20 is rotated by the rotation of the motor 68 via the torque transmission mechanism 69, and the semiconductor wafer 6 attracted to the lower surface of the top ring body 3 by the top ring cylinder 12 is fixed on the upper surface of the turntable 20. The semiconductor wafer 6 is polished by bringing the semiconductor wafer 6 into contact with each other under pressure. At this time, the top ring body 3 rotates and slides at the same time.

The semiconductor wafer 6 that has been polished is received by the polishing object transfer mechanism 66 on the unload side. The semiconductor wafer 6 on the polishing object delivery mechanism 66 is delivered to the cleaning unit 70 by the descending elevator. A liquid tank 71 containing a cleaning liquid W such as pure water is arranged in the cleaning unit 70, and a transfer roller and a cleaning roller 72 are arranged in the liquid tank 71, and the polished semiconductor wafer 6 is used for this transfer. The surface of the cleaning liquid Q is cleaned while being conveyed in the cleaning liquid Q by the roller and the cleaning roller 72.

In each of the above embodiments, the polishing apparatus for polishing the semiconductor wafer to be flat and mirror-finished has been described as an example, but the object to be polished by the polishing apparatus of the present invention is not limited to the semiconductor wafer. .

[0054]

As described above, according to the present invention, the excellent effects listed below can be obtained. (1) The top ring drive shaft and the top ring body rotate synchronously while the bottom surface of the top ring body quickly follows the tilting of the turntable surface, and the surface of the polishing target such as a semiconductor wafer is flattened. Highly accurate mirror polishing and stable polishing grade.

(2) Further, the top ring drive shaft and the top ring body rotate in synchronism with each other, so that a vacuum line from the top ring body and a line for pressurizing the top ring body against the turntable are freely designed. become able to.

(3) Further, either one or both of the drive pin provided on the top ring drive shaft and the drive pin provided on the top ring main body is provided with buffer means, and the radial bearing supporting the top ring drive shaft is fixed. By fixing the side ring or the top ring drive shaft via the buffering means, it is possible to suppress the transmission of the vibration of the top ring drive shaft to the top ring main body and the vibration itself, so that accurate polishing can be performed.

(4) Further, by providing the surface pressure adjusting means for adjusting the surface pressure distribution on the lower surface of the top ring, the surface pressure of the object to be polished can be made uniform, so that accurate polishing can be performed. .

(5) Further, the polishing object delivery mechanism is provided with a buffer mechanism so as not to give an impact force to the polishing object when delivering the polishing object to or from the top ring body.
Even if a large diameter cylinder is used to move the top ring body up and down, delicate pressure adjustment is not necessary, damage to the polishing object is not done, and delicate sensor adjustment of the polishing object delivery position is possible. You don't have to.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a polishing section of a polishing apparatus of the present invention.

FIG. 2 is a plan view showing an embodiment of a polishing section of the polishing apparatus of the present invention.

FIG. 3 is a vertical cross-sectional view showing the configuration of the polishing apparatus of the present invention.

FIG. 4 is an explanatory view illustrating the operation of the polishing section in the polishing apparatus of the present invention.

FIG. 5 is a vertical cross-sectional view showing another configuration example of the polishing section of the polishing apparatus of the present invention.

FIG. 6 is an explanatory view explaining the action of the ball bearing in the polishing portion of the polishing device of the present invention.

FIG. 7 is a vertical sectional view showing another embodiment of the polishing portion of the polishing apparatus of the present invention.

FIG. 8 is a plan view showing another embodiment of the polishing section of the polishing apparatus of the present invention.

FIG. 9 is a view showing a bearing portion of a top ring drive shaft of the polishing device of the present invention.

FIG. 10 is a diagram showing an example of surface pressure adjusting means on the lower surface of the top ring body of the polishing apparatus of the present invention.

FIG. 11 is a diagram showing a configuration example of vacuum holes formed in the top ring body of the polishing apparatus of the present invention.

FIG. 12 is a diagram showing a configuration example of vacuum holes formed in the top ring body of the polishing apparatus of the present invention.

FIG. 13 is a diagram showing a configuration example of vacuum holes formed in the top ring body of the polishing apparatus of the present invention.

FIG. 14 is a view showing the structure of a polishing object delivery mechanism installed in the polishing apparatus of the present invention.

FIG. 15 is a diagram showing a state in which a polishing object is delivered to or from the top ring using the polishing object delivery mechanism of the present invention.

FIG. 16 is a schematic diagram showing an overall configuration of an apparatus for polishing and cleaning an object to be polished.

FIG. 17 is an explanatory diagram illustrating a polishing section of a conventional polishing apparatus.

FIG. 18 is an explanatory diagram illustrating a polishing section of a conventional polishing apparatus.

FIG. 19 is an explanatory view illustrating the operation of the polishing section of the conventional polishing apparatus shown in FIGS. 17 and 18.

[Explanation of symbols]

 1 Top Ring Drive Shaft 2 Ball Bearing 3 Top Ring Main Body 4 Top Ring Holder 5 Wafer Stop Ring 6 Semiconductor Wafer 7, 8 Torque Transmission Pin 10 Vacuum Line Tube 12 Top Ring Cylinder 13 Top Ring Drive Motor 20 Turntable 23 Polishing Cloth 31 cushioning material 32 O-ring 33 radial bearing 34 cushioning mechanism 35 fixed side 36 oil sump 37 surface pressure adjusting member 51 base 52 suction piece 53 suction pad 55 vacuum line tube 57 bearing sleeve 58 bearing 60 spring 63 arm 64 elevator

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Norio Kimura 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation (72) Inventor Yu Ishii 11-11 Haneda-asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION

Claims (9)

[Claims] 1. A turntable having a polishing cloth stretched on an upper surface that rotates at an independent number of revolutions, and a top ring body, wherein a polishing object is interposed between the turntable and the top ring body. In the polishing device for polishing the surface of the polishing object by pressing with the force of, to make the surface flat and mirror-finished, the polishing device is connected to a pressing device for pressing the top ring body and rotationally drives the top ring body. A top ring drive shaft connected to the drive device, and a ball bearing is interposed between the top ring drive shaft and the top ring body, and the bottom surface of the top ring body smoothly moves along the turntable surface. A polishing device characterized by being able to follow. 2. The top ring body is provided with a plurality of suction holes, the tip of which is open to the lower surface of the top ring body and communicates with a vacuum source, and a polishing object can be vacuum-sucked to the lower surface of the top ring body. The polishing apparatus according to claim 1, wherein the polishing apparatus is configured to be capable. 3. The rotation force of the top ring drive shaft is transmitted to the top ring body by point contact between the drive pin provided on the top ring drive shaft and the drive pin provided on the top ring body. The polishing apparatus according to claim 1. 4. One or both of a drive pin provided on the top ring drive shaft and a drive pin provided on the top ring main body is provided with a cushioning means made of an elastic body that absorbs vibration, and both drive pins are 4. The polishing device according to claim 3, wherein the polishing device is contacted via a cushioning means. 5. The radial bearing supporting the top ring drive shaft is fixed to the fixed side or the top ring drive shaft via a shock absorbing mechanism that absorbs vibrations. The polishing apparatus according to item 1. 6. The polishing apparatus according to claim 1, further comprising surface pressure adjusting means for adjusting a surface pressure distribution on the lower surface of the top ring body. 7. A polishing object delivery mechanism for delivering a polishing object to or from the top ring body of the polishing apparatus,
The polishing object delivery mechanism can place a polishing object on the upper part and move it up and down, passing the polishing object to a vacuum suction section on the lower surface of the top ring body or receiving the polishing object from the vacuum suction section. The object mounting portion is provided, and the mounting portion is supported by a cushioning mechanism so as not to give an impact force to the polishing object when the polishing object is delivered. The polishing apparatus described. 8. The polishing apparatus according to claim 7, wherein the polishing object placing section is provided with a suction section for vacuum-sucking the polishing object. 9. The polishing apparatus according to claim 7, wherein the cushioning mechanism is a mechanism utilizing elastic force of a spring.