JP3973564B2 - Polishing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polishing apparatus for lapping and polishing both front and back surfaces of a work such as metal, glass, crystal, and silicon.
[0002]
[Prior art]
For example, the inventions disclosed in Patent Documents 1, 2, and 3 are disclosed as conventional polishing apparatuses.
[0003]
[Patent Document 1]
Japanese Patent No. 3262808 [Patent Document 2]
JP 2002-46062 A [Patent Document 3]
Japanese Patent Laid-Open No. 2002-57131 [0004]
[Problems to be solved by the invention]
In recent years, due to demands for high integration of semiconductors and yield improvement, polishing of workpieces such as silicon wafers is required to further improve technology such as larger diameter, flattening, and lightening. In order to realize such technological improvements, an important issue in polishing technology is how to maintain the polished surfaces of the upper and lower surface plates in parallel and in close contact with the workpiece. It has become.
[0005]
In the initial stage where there is no workpiece or carrier, the upper surface plate is in uniform contact with the lower surface plate by its own weight. However, the processing heat generated by the friction between the sandwiched work and the polishing surface of the upper surface plate, and the friction between the polishing surface of the lower surface plate, or the lower surface plate, sun gear and internal teeth incorporated in the device Heat generated by the motor that drives the gears is transmitted from the lower surface plate to the upper surface plate. As a result, there is a problem that the polishing accuracy may deteriorate due to the deformation of the upper surface plate of the suspended structure or the difference in adhesion between the upper surface plate and the lower surface plate.
[0006]
The present invention has been made to solve such problems, and an object of the present invention is to provide a polishing apparatus capable of maintaining a close contact state between an upper surface plate and a lower surface plate which are suspension structures.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a polishing apparatus according to the invention described in claim 1 includes:
Polishing to polish the upper and lower surfaces of a workpiece held in a carrier that revolves while rotating by meshing with an internal gear and a sun gear between the upper and lower surface plates facing each other or rotating between the surface plates that can rotate one side In the device
A plurality of freely rotatable pulleys are arranged concentrically and equidistantly on the upper surface plate suspension part and the upper surface plate, and at least doubly installed, and endless wires are alternately stretched between the pulleys. The upper surface plate is kept suspended from the upper surface plate suspension portion by the lifting wire and the shape control wire.
[0008]
A polishing apparatus according to the invention of claim 2 is
The polishing apparatus according to claim 1, wherein
The upper surface of the upper surface plate is provided with a detection unit that has multiple strain sensors, displacement sensors, and tilt sensors installed radially, and the shape data that is output from the detection unit when the upper surface plate is in close contact with the lower surface plate due to its own weight is stored. And a calculation unit that compares shape data obtained when the upper surface plate is lifted.
[0009]
A polishing apparatus according to the invention described in claim 3 is:
The polishing apparatus according to claim 2, wherein
A plurality of thermal actuators, linear actuators, and pneumatic actuators are installed at equal intervals on the shape control wire, and the shape control is performed by the actuator until the shape data at the time of contact is obtained, starting from the pulley block portion of the lifting wire. It is characterized by a tension adjusting mechanism that adjusts the tension of the wire and reproduces the shape at the time of close contact with the upper surface plate suspended.
[0010]
A polishing apparatus according to the invention of claim 4
The polishing apparatus according to claim 3, wherein
The upper surface of the upper surface plate is provided with a detection unit with a plurality of strain sensors, displacement sensors, and inclination sensors arranged radially. When the lower surface plate is deformed during processing, the actuator adjusts the tension of the shape control wire to It is characterized in that the upper surface plate is made to follow the lower surface plate by determining the tension by determining that it matches the shape of the lower surface plate when the stoppage of the deformation of the plate is detected.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. A polishing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the polishing apparatus of the present embodiment, FIG. 2 is a top view of an upper surface plate, FIG. 3 is an explanatory diagram for explaining a wire stretching system, and FIG. 4 is a block diagram of a control system.
[0012]
As shown in FIG. 1, the polishing apparatus has a polishing mechanism using an upper surface plate 101, a lower surface plate 102, a carrier 103, a sun gear 104, and an internal gear 105.
Further, the upper platen 101 is driven up and down by the joint 110, the cylinder shaft 111, and the cylinder 112.
[0013]
Next, the suspension mechanism of this embodiment will be described.
As shown in FIG. 1, the suspension mechanism includes an upper surface plate suspension 1, a suspension upper pulley 2, a suspension lower pulley 3, a shape control upper pulley 4, and a shape control lower pulley 5. ing.
[0014]
The upper surface plate suspending portion 1 is attached to the joint 110 and moves up and down.
A suspension upper pulley 2 configured to be rotatable is provided on the inner side of the upper surface plate suspension 1 (on the middle circle of triple concentric circles with respect to the rotation axis of the lower surface plate 102). Placed in position.
On the inner side of the upper surface plate 101 (on the middle circle of triple concentric circles with respect to the rotation axis of the lower surface plate 102), a suspension lower pulley 3 configured to be rotatable is placed at a predetermined position. Has been placed.
[0015]
Inside the upper surface plate suspension 1 (on the inner circle of the triple concentric circle with reference to the rotation axis of the lower surface plate 102) and outside (outside of the triple concentric circle with respect to the rotation surface of the lower surface plate 102) An upper pulley 4 for shape control, which is configured to be rotatable, is disposed at a predetermined position on the circle).
Inside the upper surface plate 101 (on the inner circle of the triple concentric circles with reference to the rotation axis of the lower surface plate 102) and outside (outside of the outer circle of the triple concentric circles with reference to the rotation axis of the lower surface plate 102) On the circle), a lower pulley 5 for shape control, which is configured to be rotatable, is disposed at a predetermined position.
[0016]
Endless shape (shape formed by connecting loops) to the upper pulley 2 for hanging on the inner side of the upper surface plate hanging portion 1 and the lower pulley 3 for hanging on the inner side of the upper surface plate 101 A lowering wire 6 is stretched.
For example, in this embodiment, as shown in FIG. 3 (a), the alternate suspension of the suspension upper pulley 2 → the suspension lower pulley 3 → the suspension upper pulley 2 →... It is to be stretched.
[0017]
Further, an endless shape control wire 7 is stretched between the shape control upper pulley 2 inside the upper surface plate suspension 1 and the shape control lower pulley 3 inside the upper surface plate 101. The Similarly, an endless shape control wire 7 is stretched between the shape control upper pulley 2 outside the upper surface plate suspension 1 and the shape control lower pulley 3 outside the upper surface plate 101. Is done.
For example, in the present embodiment, as shown in FIG. 3A, the alternate loop of shape control upper pulley 4 → shape control lower pulley 5 → shape control upper pulley 4 →... Is repeatedly performed. It is to be stretched.
[0018]
As shown in FIG. 3B, these upper pulleys 2 for suspension are provided with pins 2a and rollers 2b, and are arranged in the accommodating portion of the suspension plate 1a of the upper surface plate suspension 1 as shown in FIG. The Further, the shape control upper pulley 4 and the shape control wire 7 have the same configuration, and redundant description is omitted.
Moreover, the lower pulley 3 for suspension is rotatably arranged by a pulley block portion 3a as shown in FIG. Also, the shape control lower pulley 5 and the shape control wire 7 have the same configuration, and redundant description is omitted.
[0019]
The suspension wire 6 that is stretched between the suspension upper pulley 2 and the suspension lower pulley 3 is stretched so as to be substantially parallel to the vertical direction of the polishing surface of the lower surface plate 102. Is done. Furthermore, the suspension wires 6 stretched between the suspension upper pulley 2 and the suspension lower pulley 3 are arranged so that the adjacent wires are parallel to each other at a constant interval.
[0020]
The shape control wire 7 that is stretched between the shape control upper pulley 4 and the shape control lower pulley 5 is stretched and stretched so as to be substantially parallel to the vertical direction of the polishing surface of the lower surface plate 102. The Further, the shape control wires 7 stretched between the shape control upper pulley 4 and the shape control lower pulley 5 are arranged so that the adjacent wires are parallel to each other at a constant interval.
[0021]
In this embodiment, the suspension upper pulley 2, the suspension lower pulley 3, the shape control upper pulley 4, and the shape control lower pulley 5 that satisfy these conditions are attached as predetermined positions. .
[0022]
Next, shape control will be described.
For shape control, as shown in FIG. 4, the control system includes a detection unit 9, a calculation control unit 10, a storage unit 11, and an actuator 8.
As shown in FIG. 2, each detection unit 9 is installed over the inner periphery and the outer periphery of the upper surface plate 101, and can detect a change in the shape of the upper surface plate 101 at each position in the radial direction. ing. A plurality of detection units 9 are prepared and arranged in equal divisions (in FIG. 2, five detection units 9 are used and are divided into five at an equal angle of 72 °).
Specifically, the detection unit 9 is a strain sensor, a displacement sensor, or a tilt sensor, and can always be detected and measured.
[0023]
The arithmetic control unit 10 is specifically a CPU (Central Processing Unit) or the like, and receives a shape signal output from the detection unit 9 during polishing, and performs analog / digital conversion to obtain shape data.
The storage unit 11 stores shape data relating to an initial shape in which the upper surface plate 101 is in close contact with the lower surface plate 102 by its own weight. The arithmetic control unit 10 can read out the initial shape data from the storage unit 11.
[0024]
The actuator 8 has a function of expanding and contracting the shape control wire 7.
Specifically, the actuator 8 can have various configurations. For example, the actuator 8 may be a heater that applies heat to the shape control wire 7. Appropriate heat is constantly applied from the heater to the shape control wire 7 so that the shape control wire 7 extends to a predetermined length, and the heater is further heated to extend the shape control wire 7 and extend the upper surface plate. It is deformed downward by its own weight, or the upper surface plate 101 is deformed upward by decreasing the heat of the heater and contracting the shape control wire 7 to increase the tension.
[0025]
Further, instead of the heater, the actuator 8 is a cylinder, a shape memory alloy linear actuator, a thermal actuator, a linear actuator or a pneumatic actuator, and the shape of the upper surface plate 101 is adjusted by adjusting the tension of the shape control wire 7. Can be corrected.
A plurality of such actuators 8 are installed at equal intervals.
[0026]
In the shape control by such a control system, the tension of the shape control wire 7 is adjusted by the actuator 8 using the pulley block portion of the lifting wire 6 as a base point until it matches the initial shape data of the storage unit 11 at the time of contact. The tension adjustment is performed so as to reproduce the shape at the time of close contact with the upper surface plate 101 suspended. As a result, even when the upper surface plate 101 is lifted, the upper surface plate 101 is kept in close contact with the lower surface plate 102, so that the workpiece 200 is polished in parallel.
[0027]
Subsequently, when the lower surface plate 102 is deformed into a convex or concave shape with respect to the rotation center, the contact surface pressure between the workpiece 200 and the upper surface plate 101 changes. At low places, it tries to deform by its own weight. Due to the deformation of the upper surface plate 101, the upper surface plate hanging portion 1 is also deformed via the lifting wire 6 and the shape control wire 7, and the polishing of the workpiece is not parallel.
[0028]
Therefore, the deformation of the upper surface plate 101 is such that the shape data output from the detection unit 9 changes, and the arithmetic control unit 10 can determine the location where the contact surface pressure is low. The tension of the wire 7 is adjusted (specifically, adjustment is performed by extending the shape control wire 7 and lowering the upper surface plate 101 little by little at places where the contact surface pressure is low).
[0029]
As a result of this adjustment, the contact surface pressure between the workpiece 200 and the upper surface plate 101 gradually increases, and when the shape approaches the shape of the lower surface plate 102, the change in shape data decreases, and the shapes of the upper surface plate 101 and the lower surface plate 102 match. In other words, when the stop of deformation of the upper surface plate 101 is detected, the arithmetic control unit 10 determines that the shape matches the shape of the lower surface plate 101, determines the tension, and stops the operation of the actuator 8. Control to maintain tension. As a result, the upper surface plate 101 can be made to follow the lower surface plate 102.
[0030]
The embodiment of the present invention has been described above.
In the present embodiment, the planetary gear type polishing apparatus has been described in particular. However, even with other types of polishing apparatuses, the upper surface plate 101 can be applied to a polishing apparatus having a suspended structure.
The number of the upper pulley 2 for hanging, the lower pulley 3 for hanging, the upper pulley 4 for shape control, and the lower pulley 5 for shape control is appropriately selected.
[0031]
Further, in this embodiment, the shape control wire 7 is stretched double inside and outside, and the single lifting wire 6 is provided therein, but the stretching system is not limited to this.
For example, a quintuple stretch system is adopted, and a configuration is adopted in which a shape control wire → a lifting wire → a shape control wire → a lifting wire → a shape control wire is stretched from the innermost circumference to the outermost circumference. May be. The tension system is also selected as appropriate.
[0032]
【The invention's effect】
According to the present invention described above, the upper and lower surface plates of the polishing apparatus are fixed in order to cope with the problem of the prior art that the contact state is lost due to deformation due to processing heat or heat of a drive motor incorporated in the apparatus. Upper surface plate by measuring and calculating deformation amount by strain sensor, displacement sensor and tilt sensor attached to the board, and adjusting tension of shape control wire by actuator attached to shape control wire based on the data By the control mechanism that makes the shape of the lower surface plate follow the shape of the lower surface plate, the close contact state between the upper surface plate and the lower surface plate can be maintained at all times, and the workpiece can be polished with high accuracy.
[0033]
A similar effect can be expected for a polishing apparatus using a four-way system using a planetary gear motion or a rotary rocking motion system.
In general, it is possible to provide a polishing apparatus capable of maintaining a close contact state between an upper surface plate and a lower surface plate which are hanging structures.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a polishing apparatus according to an embodiment of the present invention.
FIG. 2 is a top view of the upper surface plate.
FIG. 3 is an explanatory diagram for explaining a wire stretching system.
FIG. 4 is a block diagram of a control system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper surface plate hanging part 1a Hanging plate 2 Hanging upper pulley 2a Pin 2b Roller 3 Hanging lower pulley 3a Pulley block part 4 Shape control upper pulley 5 Shape control lower pulley 6 Hanging wire 7 Shape control Wire 8 Actuator 9 Detection unit 10 Calculation control unit 11 Storage unit 101 Upper surface plate 102 Lower surface plate 103 Carrier 104 Sun gear 105 Internal gear 110 Joint 111 Cylinder shaft 112 Cylinder 200 Workpiece

Claims (4)

Polishing to polish the upper and lower surfaces of a workpiece held in a carrier that revolves while rotating by meshing with an internal gear and a sun gear between the upper and lower surface plates facing each other or rotating between the surface plates that can rotate one side In the device
A plurality of freely rotatable pulleys are arranged concentrically and equidistantly on the upper surface plate suspension part and the upper surface plate, and at least double are installed, and endless wires are alternately stretched between the pulleys. A polishing apparatus characterized in that the upper surface plate is kept suspended from the upper surface plate suspension portion by the lifting wire and the shape control wire. The polishing apparatus according to claim 1, wherein
The upper surface of the upper surface plate is provided with a detection unit that has multiple strain sensors, displacement sensors, and tilt sensors installed radially, and the shape data that is output from the detection unit when the upper surface plate is in close contact with the lower surface plate due to its own weight is stored. A polishing apparatus comprising: a storage unit configured to compare with a calculation unit that compares shape data obtained when the upper surface plate is lifted. The polishing apparatus according to claim 2, wherein
A plurality of thermal actuators, linear actuators, and pneumatic actuators are installed at equal intervals on the shape control wire, and the shape control is performed by the actuator until the shape data at the time of contact is obtained, starting from the pulley block portion of the lifting wire. A polishing apparatus comprising a tension adjusting mechanism that adjusts the tension of a wire and reproduces the shape when the upper surface plate is lifted up in close contact. The polishing apparatus according to claim 3, wherein
The upper surface of the upper surface plate is provided with a detection unit with a plurality of strain sensors, displacement sensors, and inclination sensors arranged radially. When the lower surface plate is deformed during processing, the actuator adjusts the tension of the shape control wire to A polishing apparatus characterized in that when the stoppage of deformation of a platen is detected, the upper platen is made to follow the lower platen by determining that the shape matches the shape of the lower platen and determining the tension.

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