JP2001347451A - Grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely press an overall work to be ground by uniform force by allowing a pressure plate pressing the work to be ground to a surface plate, to be deformable corresponding to the surface shape of the work to be ground or the surface shape of a grinding pad, and to simplify a structure of the grinder to reduce the cost. SOLUTION: The pressure plate 14 is composed of an upper plate member 26 made of a rigid material, a lower plate member 27 made of a rigid material and abutting on a work 11 to be ground to press the same, and a deformable soft member 28 located between flat joint faces 26a and 27a of both plate members 26 and 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polishing for planarly polishing various plate-like objects to be polished, such as semiconductor wafers, single crystal substrates used for optical equipment, optical parts and glass parts. It concerns the device.

[0002]

2. Description of the Related Art As shown in FIGS. 5 and 6, a polishing apparatus for polishing one side of a plate-like object to be polished such as a semiconductor wafer on a flat surface has a polishing pad 2 adhered to a work surface. 1 and a pressure plate 4 for holding an object 3 to be polished, and a polishing pad 2 of a polishing platen 1 for rotating the object 3 held on the pressure plate 4
It is configured to be pressed against and polished.

[0003] The pressure plate 4 generally comprises
It is made of a rigid material such as aluminum or stainless steel, and directly presses the polished object 3 therewith.
However, as shown in FIGS. 7 and 8, when the surface of the object to be polished 3 has a convex or concave curved surface shape or is inclined, the pressure plate 4 which is a rigid body is Since it was not possible to adhere to the entire surface of the object 3 to be polished, a uniform force could not be applied over the entire surface, and uneven polishing occurred, making it difficult to perform uniform polishing. In FIGS. 7 and 8, the convex shape or the concave shape of the surface of the object to be polished is exaggerated for easy understanding.
The actual irregularities are much smaller.

On the other hand, a large-diameter pressure plate is used to grind a large-diameter work piece. However, the large-diameter pressure plate has a large weight, so that it may be formed of a rigid material. Slight bending due to its own weight occurs, and this bending often hinders uniform polishing. In particular, there has been a problem that the outer peripheral side of the pressure plate is deformed downward, and too much pressure is applied to the outer peripheral side of the workpiece.

Conventionally, the surface of the object to be polished is formed by forming a portion of the pressure plate in contact with the object to be polished by an elastically deformable soft member or by providing an elastically deformable mechanism inside the pressure plate. The followability to the shape is improved, whereby the polishing accuracy is improved, and the polishing and polishing of the worn-out polishing cloth and the leveling operation are reduced so that the polishing can be performed efficiently.

For example, Japanese Patent Application Laid-Open No. Sho 54-1000059 discloses that an air bag is used as a backup material so that the polished surface of a polishing tool can be easily deformed by the air bag, and the shape of a glass part to be polished during rotary polishing is reduced. Is disclosed with respect to a polishing apparatus capable of following the above.

Japanese Patent Application Laid-Open No. Hei 7-205017 discloses that a soft plate is adhered to a base plate for holding a work.
By sticking the work to this soft plate and pressing it against the polishing plate, by arranging a control ring surrounding the outer periphery of the work,
There is disclosed a pressure plate characterized by absorbing and polishing a surface roughness of a complicated shape remaining on a semiconductor wafer which is a work by a soft plate adhered to a base plate.

Further, Japanese Patent Application Laid-Open No. Hei 7-314301 discloses a fluid supply means for attaching a flexible film to a pressurizing body for pressing a work against a polishing plate and supplying a fluid to the back side of the stiffened film. There is disclosed an apparatus in which a work in contact with the flexible film body is pressed against a polishing plate by the action of fluid pressure acting on the flexible film body.

Japanese Patent Application Laid-Open No. H10-128656 discloses that a processing head for pressing an object to be polished against a surface plate is divided into a support plate connected to a main shaft and a holding plate for holding an object to be polished. The support plate and the holding plate are concentrically and in parallel to each other by a plurality of elastic connecting members that are highly rigid in the circumferential direction of the spindle rotation and elastically deform in a direction perpendicular to the polishing surface of the surface plate. A consolidation is disclosed.

Furthermore, Japanese Patent Application Laid-Open No. H11-333696 discloses a polishing apparatus in which a pressure plate for pressing a glass substrate against a polishing platen is formed of a soft member that can be deformed in accordance with the abrasion state of a polishing surface of a polishing cloth. It has been disclosed. A plurality of reinforcing ribs are radially attached to the upper surface of the pressure plate, and the ribs are gradually thinner while the top surface is curved from the center line to the outer side.

However, any of the above-mentioned known examples is
There are drawbacks in that the structure is complicated, the cost is high, and it takes time and effort to set the object to be polished. Further, in a system in which a workpiece is directly pressed by a soft member, when polishing a large-diameter object to be polished, a force for suppressing the object to be polished is small, and the object to be polished may be shifted.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing apparatus having a polishing platen for polishing an object to be polished and a pressure plate for pressing the object to be polished against the polishing platen. By making the pressure plate deformable according to the surface shape of the object to be polished or the surface shape of the polishing pad, the entire object to be polished can be reliably pressed with a uniform force, and its structure is reduced. The goal is to simplify and reduce costs.

[0013]

According to the present invention, there is provided a polishing plate having a polishing pad adhered to a surface thereof, a driving means for rotating the polishing plate, and an object to be polished. A pressure plate having a disc shape for pressing the polishing plate against the polishing platen, and a pressure mechanism for applying a pressing force to the pressure plate, wherein the pressure plate is attached to the body by a shaft connected to a central portion of the upper surface. An upper plate member made of a rigid material, which is supported and connected to the shaft, is divided into a lower plate member made of a rigid material that comes into contact with the object to be polished, and a flat joint surface between these two plate members is provided. A polishing apparatus is provided, in which a deformable soft member is interposed therebetween.

In the present invention, since the pressure plate has only a soft member interposed between upper and lower plate members made of a rigid material, its structure is very simple and simple, and it can be manufactured at low cost. Can be.

Further, since the object to be polished is brought into contact with and held by a lower plate member made of a rigid material, and the lower plate member is pressed by the upper plate member via the soft member, a soft material such as a sponge is used. Compared with the conventional example in which the member is brought into direct contact with the object to be polished and pressed, the setting of the object to be polished is not only easy and can be performed in a short time, The object to be polished does not shift.

Further, even if the surface of the object to be polished or the surface of the polishing pad has a curved surface such as a concave surface or a convex surface or is inclined, the lower plate member of the pressure plate follows the soft member. The lower plate member is brought into close contact with the surface of the object to be polished and uniformly applies pressure to the entire surface thereof. Therefore, the object to be polished can be uniformly polished over the entire surface, and the polishing accuracy is improved.

According to a specific embodiment of the present invention, the upper plate member of the pressure plate has a thick portion which is located at the center and rises to the upper surface side, and an outer peripheral side which surrounds the thick portion. And a plurality of reinforcing ribs radially formed on the upper surface of the thin portion, and the lower plate member has a disk shape with a uniform thickness as a whole. The member and the lower plate member are connected to each other via the soft member by a bolt attached to a position near the outer peripheral end of the thick portion of the upper plate member.

Thus, by utilizing the thick portion of the upper plate member, the soft member and the lower plate member can be connected accurately and accurately without deformation due to bolt tightening.

In the present invention, the soft member can be formed of any one of neocell sponge, silicone rubber, and natural rubber.

[0020]

FIG. 1 is an overall view of a preferred embodiment of a polishing apparatus according to the present invention. The polishing apparatus includes a body 10, a rotatable platen 12 for polishing a substantially plate-shaped object 11 to be polished with a polishing pad 12 a stuck on the surface, and a driving rotation of the platen 12. A pressure plate 14 for pressing the workpiece 11 against the polishing pad 12a of the surface plate 12 with a predetermined pressing force, a pressing mechanism 15 for generating the pressing force, A swinging mechanism 16 for moving the pressure plate 14 to the left and right at a constant period during the polishing in order to polish the polished object 11 uniformly, and inverting the pressure plate 14 vertically when the polished object 11 is carried in and out. And a head reversing mechanism 17 for performing the rotation.

First, the platen driving unit 13 will be described. The platen drive unit 13 is connected to a lower surface of a central portion of the platen 12 and is supported by a main body 20 so as to be rotatable by the body 10.
And a motor 2 with a speed reduction mechanism installed on the airframe 10
1, the drive shaft 21a of the motor 21 and the main shaft 20
V pulleys 22a and 22b respectively attached to
And a V-belt (not shown) connecting these pulleys 22a and 22b. The rotation torque from the motor 21 is transmitted to a speed reducer to reduce the rotation speed to a constant speed, and the V belt and the V pulley 22b are attached to the drive shaft 21a from the V pulley 22a.
Is transmitted to the main shaft 20 of the surface plate 12 through which the surface plate 12 is driven and rotated. Note that couplings are attached to the base 12 and the main shaft 20, respectively, so that they are kept horizontal.

On the other hand, the pressure plate 14
An end of an arm 24 rotatably supported by the body 10 by the swing mechanism 16 is suspended by a shaft 25. The pressure plate 14 has a disk shape as a whole, and as can be seen from FIG. 2, an upper plate member 26 made of a rigid material such as aluminum or stainless steel and a lower plate member 27 made of a similar rigid material.
These two plate members 26, 27
An elastically deformable soft member 28 such as neocell sponge, silicon rubber or natural rubber is interposed between the opposed flat joining surfaces 26a and 27a.

The upper plate member 26 has a thickened portion 26b which is located at the center and is bulged circularly on the upper surface side,
By providing an annular outer peripheral thin portion 26c surrounding the thick portion 26b, rigidity at the central portion is increased to make it harder to deform, and the outer peripheral side is lightened to reduce deformation due to its own weight. Less likely to occur. Further, a plurality of reinforcing ribs 29 extending radially are formed on the upper surface of the thin portion 26c. These ribs 29 have the same inner height as the upper surface of the thin portion 26c, and gradually become higher outward. Is low. On the other hand, the lower plate member 27 has a disk shape with a uniform thickness as a whole,
The thickness is the thin portion 26c of the upper plate member 26.
It is formed to be slightly thicker so that it can be slightly elastically deformed following the surface shape of the object to be polished 11 or the surface shape of the polishing pad 12a during polishing. The upper plate member 26 and the lower plate member 27 are provided with a plurality of bolts 30 radially disposed at equal angular intervals at a position near the outer peripheral end of the thick portion 26b of the upper plate member 26.
Are connected to each other via the soft member 28. Further, the soft member 28 has a uniform thickness as a whole, but the thickness is desirably about 10 to 30 mm. By forming the soft member 28 to such a thickness, even if the upper plate member 26 is deformed by its own weight during the polishing process, it can be absorbed, and the lower portion corresponding to the surface shape of the workpiece 11 can be absorbed. The bending of the plate member 27 can be enabled.

Further, as described above, the upper plate member 2
6 by bolting the two plate members 26 and 27 and the soft member 28 using the rigid thick wall portion 26b.
And can be connected with high accuracy without deformation or the like caused by tightening of the bolt 30.

The thick portion 26 of the upper plate member 26
A housing 33 for a bearing is fixed to a central portion of the upper surface of the shaft 2 by a cap bolt 34, and the shaft 2 is inserted through a self-aligning bearing 35 provided in the housing 33.
5 is rotatably connected to the center of the upper surface of the upper plate member 26. Reference numeral 36 in the figure denotes a grease nipple for injecting lubricating oil into the bearing.

As described above, the pressure plate 14
Since only the soft member 28 is interposed between the upper and lower plate members 26 and 27 made of a rigid material, the structure is very simple and simple, and can be manufactured at low cost.

As shown in FIG. 1, the upper end of the shaft 25 is rotatably supported at the tip of the arm 24 by a pin 38. The shaft 25 is pivoted about the pin 38 by the head reversing mechanism 17. By rotating,
The pressure plate 14 can be turned and inverted toward the front of the body 10. The head reversing mechanism 17 includes a gear motor 39 in which a motor and a speed reducer are integrated, and a gear motor 39
And a rod end 41 and a reversing shaft 42 connected between the feed screw 40 and the end of the shaft 25. The feed screw 4 is moved by the gear motor 39.
0 is retracted, the rod end 41 is pulled and rotates together with the reversing shaft 42, and accordingly, the shaft 25 rotates upward and the pressure plate 14
Will be lifted up.

In polishing the work 11, the work 11 is waxed on the lower surface (pressing surface) of the lower plate member 27 of the pressure plate 14 with the pressure plate 14 turned upside down as described above. Then, the pressure plate 14 is returned to the position shown in FIG. 1, and the held object 11 is pressed against the polishing pad 12a of the rotating platen 12 for polishing.

The pressing force at the time of processing the object to be polished 11 is generated by the pressing mechanism 15. The pressure mechanism 15 includes a pressure cylinder 45 supported by a housing 44 of the swing mechanism 16, and a rod 45 a of the pressure cylinder 45 is connected to a rear end of the arm 24. When the rod 45a of the pressurizing cylinder 45 extends, the arm 24 is pivoted on the support shaft 46 as a fulcrum.
Of the pressure plate 14
The object 11 to be polished is held down and pressed against the surface plate 12 with a set force.

Thus, the polishing apparatus causes the workpiece 11 to contact and hold the lower plate member 27 made of a rigid material, and press the lower plate member 27 with the upper plate member 26 via the soft member 28. Because
Compared with a conventional example in which a soft member 28 such as a sponge is directly brought into contact with the workpiece 11 and pressurized, the setting of the workpiece 11 is easy and can be performed in a short time. And the object 11 to be polished does not shift during polishing.

A soft member which has a thickness such that the lower plate member 27 can be slightly elastically deformed and has a larger elastic deformation than the lower plate member 27 between the lower plate member 27 and the upper plate member 26. 3 and 4, the surface of the object to be polished 11 and the surface of the polishing pad 12a have a curved surface such as a convex surface or a concave surface, or are inclined, as shown in FIGS. Also,
Following this, the lower plate member 27 is
8 is surely deformed by deforming the object 1 to be polished.
In this manner, pressure is applied to the entire surface of the substrate 1 closely and uniformly. Therefore, the object to be polished 11 can be uniformly polished over the entire surface, and polishing accuracy is improved. In this case, the upper plate member 26 follows the lower plate member 27 because the soft member 28 serves as a cushion and absorbs the deformation of the lower plate member 27 and does not transmit the deformation force to the upper plate member 26. No deformation. In addition, in the case where the object to be polished 11 is particularly polished, there is a problem that too much pressure is applied to the central portion and the material is excessively shaved, as in the case where the object to be polished is pressed with a conventional pressure plate that does not provide necessary bending. Disappears.

During the above-mentioned polishing, the pressure plate 1
The swing mechanism 16 for moving the body 4 includes the housing 44 attached to the body 10, a swing shaft 47 supported by the housing 44 so as to be swingable in a horizontal direction, and a swing shaft attached to the body 10. A oscillating motor 48, an oscillating speed reducer 50 connected to the oscillating motor 48 via an input shaft coupling 49, and an output shaft 50a of the oscillating speed reducer 50 and the oscillating shaft 47 are connected. And an output shaft coupling 51. The arm 24 is rotatably connected to the upper end of the swing shaft 47 by a support shaft 46. Then, when the rotational torque of the oscillating motor 48 is transmitted to the speed reducer 50 via the input shaft coupling 49, the speed is reduced to the speed required for oscillating here, and then via the output shaft coupling 51. To the swing shaft 47, and the entire arm 24 swings together with the swing shaft 47. As a result, the pressure plate 14 swings left and right during polishing, and uniform polishing is performed.

[0033]

As described above, according to the present invention, there is provided a polishing apparatus comprising: a polishing platen for polishing an object to be polished; and a pressure plate for pressing the object to be polished against the polishing surface plate. By making the pressure plate deformable according to the surface shape of the object to be polished or the surface shape of the polishing pad, the entire object to be polished can be reliably pressed with a uniform force, and its structure can be simplified. Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a polishing apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a sectional view of a main part showing an example of polishing by the polishing apparatus of FIG. 1;

FIG. 4 is a sectional view of a principal part showing another example of polishing by the polishing apparatus of FIG. 1;

FIG. 5 is a side view of a conventional polishing apparatus.

FIG. 6 is an enlarged view of a main part of FIG. 5;

FIG. 7 is a sectional view of a main part showing an example of polishing by the polishing apparatus of FIG. 5;

8 is a cross-sectional view of a principal part showing another example of polishing by the polishing apparatus of FIG. 5;

[Explanation of symbols]

 Reference Signs List 10 body 11 polished object 12 surface plate 12a polishing pad 14 pressure plate 15 pressure mechanism 25 shaft 26 upper plate member 27 lower plate member 26a, 27a joining surface 26b thick portion 26c thin portion 28 soft member 30 bolt

Claims (3)

[Claims] A polishing plate having a polishing pad adhered to a surface thereof; a driving means for rotating the polishing plate; and a disk-shaped pressure plate for pressing an object to be polished against the polishing plate. And a pressurizing mechanism for applying a pressing force to the pressure plate, wherein the pressure plate is supported by a fuselage by a shaft connected to a central portion of an upper surface, and is made of a rigid material to which the shaft is connected. The upper plate member is divided into a lower plate member made of a rigid material and pressed against the object to be polished, and a deformable soft member is interposed between the flat joining surfaces of the two plate members. Polishing apparatus, characterized in that: 2. A polishing apparatus according to claim 1, wherein said upper plate member of said pressure plate has a thick portion which is located at a central portion and rises to an upper surface side, and an outer peripheral portion surrounding said thick portion. A thin portion, a plurality of reinforcing ribs radially formed on an upper surface of the thin portion, and a lower plate member having a disk shape having a uniform thickness as a whole; And a lower plate member is connected to each other by a bolt disposed at a position near an outer peripheral end of a thick portion of the upper plate member via the soft member. 3. The polishing apparatus according to claim 1, wherein the soft member is made of one of neocell sponge, silicone rubber, and natural rubber.