JP4051122B2 - Double-side polishing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a double-side polishing apparatus. Conventionally, as a double-side polishing apparatus, an external gear (hereinafter referred to as an “external gear”) and an internal gear (hereinafter referred to as an “internal gear”) are rotated at different angular velocities to process a material (hereinafter referred to as “workpiece”). The carrier corresponding to the planetary gear carrying the carrier is rotated and revolved, and the upper and lower surface plates having the polishing surfaces arranged above and below the carrier sandwich the workpiece from above and below and move relative to the workpiece. Some of them use a planetary gear mechanism for polishing. This double-sided polishing machine is used as a lapping machine (lapping machine) or a polishing machine, which has high accuracy and can polish both sides simultaneously, so that the processing time is short, and thin objects such as silicon wafers that are used as semiconductor chip materials can be polished. Suitable for
[0002]
[Prior art]
A configuration of a polishing apparatus using a conventional planetary gear mechanism will be described with reference to FIG.
112 is an upper surface plate and 114 is a lower surface plate. A polishing cloth (cross) is attached to each surface, and a polishing surface is formed by the polishing cloth. 116 is an external gear, and 118 is an internal gear. Reference numeral 120 denotes a carrier. The workpiece 121 is held in a through hole formed in the carrier 120, and the external gear 116 and the internal gear 118 are engaged with each other to rotate.
The upper surface plate 112 is connected to an upper surface plate turner 112a, and a gear 112c is provided at the tip of a shaft 112b suspended from the upper surface plate turner 112a. The gear 112c meshes with the idle gear 112d, and the idle gear 112d meshes with the gear 112e. The gear 112e is provided coaxially with the spindle 126 so as to rotate integrally with the spindle 126. The lower surface plate 114 is connected to a gear 114 b provided coaxially with the spindle 126 via a gear 114 a provided coaxially with the lower surface plate 114. The external gear 116 is connected to a transmission gear 116 b provided coaxially with the spindle 126 via a gear 116 a provided coaxially with the external gear 116. The internal gear 118 is connected to a transmission gear 118 b provided coaxially with the spindle 126 via a gear 118 a provided coaxially with the internal gear 118. That is, this polishing apparatus is a so-called four-way drive system in which the external gear 116, the internal gear 118, and the upper and lower surface plates 112, 114 are rotationally driven by one drive device.
The spindle 126 is connected to a variable speed reducer 132. The variable speed reducer 132 is connected to a motor 134 via a belt 136, and controls the rotational speed of the spindle 126.
[0003]
According to the polishing apparatus using this planetary gear mechanism, for example, the rotation ratio between the gear 116a and the transmission gear 116b and the transmission with the gear 118a so that the angular speed of the internal gear 118 is larger than the angular speed of the external gear 116. When the rotation ratios of the gears 118b are set, the carrier 120 meshed between the external gear 116 and the internal gear 118 has the same direction as the rotation direction of the internal gear 118 (for example, “counterclockwise”). Revolves and rotates clockwise. Similarly, the lower surface plate 114 rotates counterclockwise, but the upper surface plate 112 rotates clockwise because of the idle gear 112d.
Depending on the polishing conditions, the rotational direction and rotational speed of the carrier 120 can be changed by setting the angular speeds of the external gear 116 and the internal gear 118.
Further, a liquid abrasive containing slurry or the like is supplied to the front and back polished surfaces of the workpiece 121, and the workpiece 121 is suitably polished by the action of the liquid abrasive.
According to this polishing apparatus, since the carrier 120 can be moved in a complicated manner, polishing unevenness can be prevented and the workpiece 121 (for example, a silicon wafer) can be uniformly polished. Therefore, the flatness of the workpiece can be improved. Moreover, since both surfaces of the workpiece 121 can be polished simultaneously, the polishing efficiency can be improved.
[0004]
However, since the double-side polishing apparatus using the conventional planetary gear mechanism has a structure in which the carrier 120 moves between the external gear 116 and the internal gear 118, it can cope with the recent increase in size of the workpiece 121 such as a silicon wafer. Hateful. That is, it is impossible to make the diameter of the carrier 120 larger than the radius of the surface plate, and the polished surface of the surface plate cannot be used efficiently.
Moreover, in the double-side polishing apparatus using the conventional planetary gear mechanism, it is a complicated gear mechanism, and it is difficult to increase the size, and in order to manufacture a large apparatus, problems in materials, processing, arrangement space, etc. Cost increases in various aspects.
[0005]
Therefore, the applicant of the present application has developed the following double-side polishing apparatus as background art. FIG. 7 is an explanatory diagram of the background art, FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view.
In this background art, a carrier 12 in which a through hole 12a is provided in a thin flat plate and a wafer 10 which is a plate-like workpiece disposed in the through hole 12a of the carrier 12 are sandwiched from above and below and the wafer 10 is sandwiched between the carrier 10 and the wafer 10. A double-side polishing apparatus comprising upper and lower surface plates 14 and 16 that move relative to each other and polish, and the carrier 12 does not rotate in a plane parallel to the surface of the carrier 12 via the carrier holder 22. A carrier circular motion mechanism 20 (refer to FIGS. 3 and 4) is provided that moves the wafer 10 held between the upper and lower surface plates 14 and 16 within the through-hole 12a.
The upper and lower surface plates 14 and 16 are provided so as to rotate (rotate), respectively.
[0006]
In the double-side polishing apparatus of FIG. 7, the upper and lower polishing surfaces 14 a and 16 a are reduced to a concave shape corresponding to the position where the wafer 10 is held by polishing the wafer 10 as shown in FIG. 8. 8A is a cross-sectional view showing the state of the upper and lower surface plates 14 and 16 and the wafer 10 before starting the polishing process, and FIG. 8B is the upper and lower surface plate 14 after the polishing process. 16 is a cross-sectional view showing the state of 16 and the wafer 10. FIG.
As described above, the reason why the upper and lower polishing surfaces 14a and 16a are reduced is mainly because a small number of wafers 10 are processed by a limited surface plate due to restrictions on the size of the apparatus. This is caused by the restriction of the arrangement, and the upper and lower surface plates 14 and 16 rotate. Therefore, portions with a large amount of wear appear in a ring shape on the upper and lower polishing surfaces 14a and 16a. That is, the upper and lower polishing surfaces 14a and 16a (near the center of the radius) corresponding to the vicinity of the central portion of the wafer 10 may be used for polishing depending on the circular motion that does not rotate and is eccentric to the degree of the double-side polishing apparatus of FIG. Compared to high, the upper and lower polishing surfaces 14a and 16a corresponding to the periphery of the wafer 10 and corresponding to both ends of the radius (parts from the center of the circle and from the outer periphery of the circle) are less frequently used for polishing. , The above-mentioned decrement occurs, and the uniformity is lost.
Due to the difference in the usage of the upper and lower polishing surfaces 14a and 16a, the wafer 10 is polished into a convex lens shape (drum-shaped cross section) as shown in FIG. 8B.
[0007]
Therefore, in order to correct the polishing surfaces 14a, 16a to be flat, as shown in FIG. 9, after the polishing process, the polishing surface correction ring 62 is held by the correction carrier 60, and the correction carrier 60 is corrected. It is possible to consider a method in which the portions of the polishing surfaces 14a and 16a that have not been worn out are worn out by moving the same as the carrier 12 in the polishing step (see FIG. 7). The correction ring 62 is disposed and held in a large through hole 60a formed large in the correction carrier 60, and a through hole 62a having a size corresponding to the diameter of the wafer 10 is formed in the inner peripheral portion. And is used in a process (a process for correcting the polished surface) different from the polishing process of the wafer 10. Further, the correction ring 62 formed of glass, ceramic, or the like, and having a surface that is appropriately rough can correct the polished surfaces 14a and 16a efficiently. For example, it is conceivable to use a slightly thick material in consideration of durability. According to the correction ring 62, it is possible to correct the polished surfaces 14a and 16a where the side cut is generated as shown in FIG. FIG. 10A is a cross-sectional view showing a state before starting the polishing step, and FIG. 10B is a cross-sectional view showing a state after performing the polishing step, but the polishing surfaces 14a and 16a are correction rings. It is corrected to be flat by the action of 62, and the wafer 10 can be polished flatly as shown in FIG.
[0008]
[Problems to be solved by the invention]
However, as described above, in order to correct (seasoning) the shapes of the polished surfaces 14a and 16a deteriorated by polishing, a correction ring 62 or the like is provided between the polished surface 14a and the polished surface 16a in a step different from the polishing step. However, there is a problem that the operating rate of the double-side polishing apparatus is lowered. That is, the work carrier 12 and the correction carrier 60 must be replaced, which takes time. In particular, since the work is held by the carrier 12 that makes a circular motion that does not rotate, and the polishing is performed, the polishing surfaces 14a and 16a are likely to deteriorate, and it is necessary to frequently modify the polishing surfaces 14a and 16a. And the automation becomes difficult.
[0009]
Accordingly, an object of the present invention is to keep the state of the polishing surface formed by a cloth or the like constant and to improve the polishing accuracy of the workpiece by suitably applying a seasoning tool (correcting member) during workpiece processing. An object of the present invention is to provide a double-side polishing apparatus with excellent operating efficiency.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises the following arrangement. That is, the double-side polishing apparatus according to the present invention sandwiches a carrier in which a through-hole is provided in a thin flat plate and a plate-like workpiece disposed in the through-hole of the carrier from above and below and is relative to the workpiece. The upper and lower surface plates having a polishing surface to be moved and polished, and the carrier is moved in a plane parallel to the surface of the carrier, and held between the upper and lower surface plates in the through hole. A movement mechanism for moving the workpiece and a thickness equivalent to that of the workpiece, held together with the workpiece on the carrier, and correcting both polishing surfaces of the upper and lower surface plates simultaneously with the workpiece double-side polishing step. A correction member , and the correction member is formed in a ring shape having a larger diameter than the work and capable of accommodating the work therein, and the through hole of the carrier is large enough to accommodate the correction member. Formed in the through hole of the carrier, Accommodating the correcting member, and performing the polishing of the workpiece to accommodate the workpiece to the correcting member.
[0011]
The movement mechanism causes the carrier to make a circular movement that does not rotate in a plane parallel to the surface of the carrier, and the work held between the upper and lower surface plates in the through-hole is swung. By using the carrier circular motion mechanism, the workpiece can be suitably polished with a smooth motion .
[0012]
The carrier circular motion mechanism includes a carrier holder that holds the carrier, a holder-side axis that is parallel to the axis of the upper and lower surface plates, and that is parallel to the holder-side axis. A circular motion that includes a base-side shaft that is pivotally attached to the base at a predetermined distance, and that rotates the holder-side shaft about the base-side axis so that the carrier holder does not rotate with respect to the base. Is provided with an eccentric arm that rotates and a rotation drive device that rotates the eccentric arm around the base-side axis, but has a simple structure, but the circular movement that does not suitably rotate the carrier held by the carrier holder Can be made.
[0013]
Further, a plurality of the eccentric arms are provided, and the base-side shafts are connected by a synchronization means such as a timing chain so that the plurality of eccentric arms are synchronously moved in a circular motion. Can be moved in a suitable and stable manner.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First, the configuration of a double-side polishing apparatus that is a premise of the present invention will be described with reference to FIGS.
FIG. 3 is a perspective assembly view schematically showing one embodiment of a double-side polishing apparatus according to the present invention, and FIG. 4 is a side sectional view showing the positional relationship of each component when the embodiment of FIG. 3 is operating. FIG.
The present embodiment is a double-side polishing apparatus for polishing a silicon wafer 10 which is a plate-like workpiece, and is provided in a carrier 12 having a thin flat plate provided with a through hole 12a and disposed in the through hole of the carrier 12. Upper and lower surface plates 14 and 16 that sandwich the wafer 10 from above and below and move relative to the wafer 10 for polishing are provided. A polishing cloth 14a, 16a called a cloth is attached to the surface of each of the upper and lower surface plates 14, 16, and a polishing surface is formed by the polishing cloth 14a, 16a. The wafer 10 is circular and is loosely fitted in the circular through-hole 12a, and has a size that can rotate freely in the through-hole 12a.
The carrier 12 is generally formed of, for example, a glass epoxy plate and is set to have a thickness of about 0 or 7 mm with respect to a wafer 10 having a thickness of 0 or 8 mm.
[0015]
A carrier circular motion mechanism 20 moves the carrier 12 in a plane parallel to the surface of the carrier 12, and moves the wafer 10 held between the upper and lower surface plates 14 and 16 in the through hole 12a. It is an example of the exercise | movement mechanism to be made. The carrier circular motion mechanism 20 in the present embodiment causes the carrier 12 to make a circular motion that does not rotate in a plane parallel to the surface of the carrier 12, and is held in the through-hole 12 a so as to hold the upper surface plate 14 and the lower surface plate 16. The wafer 10 sandwiched by is rotated. That is, when the thickness of the carrier 12 is not considered, the carrier 12 is caused to perform a circular motion that does not rotate within the same plane as the surface of the carrier 12.
A specific configuration of the carrier circular motion mechanism 20 will be described below.
[0016]
A carrier holder 22 is formed in a ring shape and holds the carrier 12.
Here, the connecting means 50 for connecting the carrier 12 and the carrier holder 22 will be described. FIG. 5 is a partial sectional view showing an example of the connecting means 50.
The linking means 50 holds the carrier 12 by linking it to the carrier holder 22 so that the carrier 12 does not rotate and absorbs expansion due to thermal expansion of the carrier 12.
In the linking means 50 of this embodiment, as shown in FIG. 5, the pin 23 provided on the carrier holder 22 side and the direction of elongation due to thermal expansion of the carrier 12 to the carrier 12 to be loosely fitted to the pin 23 (this embodiment) In the example, a hole 12b is formed with a clearance provided in the radial direction of the circular carrier 12. The clearance of the hole 12b may be suitably provided at least in the direction of absorbing the elongation due to the thermal expansion of the carrier 12, and may be formed, for example, as a long hole.
[0017]
Further, in this embodiment, the carrier 12 is formed so that a clearance is generated between the carrier 12 and the inner peripheral surface 22a of the carrier holder 22 so that the carrier 12 can slide suitably when thermally expanded. That is, the outer diameter of the carrier 12 is smaller than the inner diameter of the inner peripheral surface 22a by a predetermined size.
As described above, the hole 12b of the carrier 12 provided with a clearance in consideration of the thermal expansion of the carrier 12 is directly set by fitting into the pin 23 of the carrier holder 22.
Thus, by providing the connecting means 50 for absorbing the elongation due to the thermal expansion of the carrier 12, the carrier 12 can be suitably connected to the carrier holder 22 in a state of being prevented from rotating with a simple configuration.
Thereby, the elongation of the carrier 12 can be suitably released and absorbed, and the deformation of the carrier 12 can be prevented. Further, since the carrier 12 is configured to be fitted by being fitted to the carrier holder 22, the work at the time of loading is simplified.
[0018]
Next, the height adjustment function of the carrier 12 provided in the carrier holder 22 will be described.
Reference numeral 23 a denotes a flange portion, which is integrally provided in a washer shape in the middle portion of the pin 23. The flange portion 23a is provided on the carrier holder 22 side and serves as a support portion that directly supports the carrier 12 so as to hold it. A screw portion 23b is provided below the flange portion 23a of the pin 23 so that the pin 23 can be attached to the lower step portion 22b of the carrier holder 22. The height of the flange portion 23a can be adjusted by adjusting the degree of screwing of the screw portion 23b to the lower step portion 22b of the carrier holder 22. By providing the flange portion 23a in this manner, the carrier 12 can be appropriately held by the carrier holder 22 by suitably adjusting the height position of the carrier 12.
[0019]
That is, by adjusting the height of the flange portion 23a, it is possible to suitably cope with a change in conditions such as when the polishing cloth 16a of the lower surface plate 16 is consumed and thinned, and the surface of the polishing cloth 16a of the lower surface plate 16 is almost the same. At the same height, the carrier 12 can be suitably held so as not to bend. Therefore, the carrier 12 can be suitably held horizontally, and polishing cracks of the wafer 10 and deterioration of the polishing accuracy can be prevented.
Further, the outer peripheral surface of the carrier 12 is partially received by the surface of the flange portion 23a, and the sliding due to the expansion and contraction of the carrier 12 can be suitably supported. That is, since the contact area between the outer peripheral surface (lower surface) of the carrier 12 and the upper surface on the carrier holder 22 side can be reduced, the sliding frictional resistance can be reduced, and the carrier 12 can slide suitably. Thereby, the expansion and contraction force due to heat or the like of the carrier 12 is preferably released, and the occurrence of distortion of the carrier 12 can be prevented.
[0020]
In the above-described embodiment, the support height of the carrier 12 is adjusted by adjusting the height of the flange portion 23a of the pin 23. However, the present invention is not limited to this, and the carrier 12 is set to a predetermined value. The structure is not particularly limited as long as it is a suitable means that can support the height of the film.
For example, a mechanism for raising and lowering the carrier holder 22 itself and providing a support for supporting the carrier 12 may be basically the upper surface of the lower step 22 b of the carrier holder 22. Of course, the upper surface of the lower step portion 22b may be provided with unevenness in order to improve slipperiness.
[0021]
Next, another configuration of the carrier circular motion mechanism 20 will be described with reference to FIGS. 3 and 4.
Reference numeral 24 denotes an eccentric arm, which is parallel to the axis L of the upper and lower surface plates 14 and 16 and is mounted on the carrier holder 22 and is parallel to the holder-side shaft 24a and has a predetermined distance. A base-side shaft 24b that is pivotally attached to the base 30 (see FIG. 4). That is, it is formed to have the same function as the crank arm of the crank mechanism.
In this embodiment, the eccentric arms 24 are arranged at four positions between the base 30 and the carrier holder 22 to support the carrier holder 22 and to turn the holder-side shaft 24a around the base-side shaft 24b. Thus, the carrier holder 22 is caused to perform a circular motion that does not rotate with respect to the base body 30. The holder-side shaft 24 a is rotatably inserted into a bearing portion 22 c provided so as to protrude from the outer peripheral surface of the carrier holder 22. As a result, the carrier 12 rotates eccentrically M from the axis L of the upper and lower surface plates 14 and 16 (a circular motion that does not rotate). The radius of the circular motion is the same as the distance between the holder-side shaft 24a and the base-side shaft 24b (the distance of the eccentricity M), and all points of the carrier 12 are the motion of drawing the same small circle locus. .
[0022]
Reference numeral 28 denotes a timing chain, which is wound around sprockets 25 (four in this embodiment) fixed coaxially to the base-side shaft 24b of each eccentric arm 24. The timing chain 28 and the four sprockets 25 constitute a synchronizing means that links and synchronizes the four base body side shafts 24b so that the four eccentric arms 24 are synchronously moved in a circular motion. This synchronization means has a simple configuration and can move the carrier 12 in a suitable and stable manner. As a result, the polishing accuracy can be improved, and the flatness of the wafer can be improved. The synchronizing means is not limited to the present embodiment, and it is needless to say that a timing belt or a gear may be used.
Reference numeral 32 denotes a motor (for example, a geared motor), and 34 denotes an output gear fixed to the output shaft. The output gear 34 meshes with a gear 26 that is coaxially fixed to the shaft 24 b on the base side of the eccentric arm 24. As a result, a rotary drive device that rotates the eccentric arm 24 about the base-side shaft 24b is configured.
[0023]
As the rotation drive device, a plurality of motors (for example, electric motors) arranged corresponding to the respective eccentric arms 24 can be used. If the electric motor is used, the plurality of eccentric arms 24 can be moved synchronously and the carrier 12 can be moved smoothly by being electrically synchronized.
In the present embodiment, the case where four eccentric arms 24 are arranged has been described. However, the present invention is not limited to this, and the carrier holder 22 can be suitably supported if there are at least three eccentric arms 24. .
Further, if the moving body of the XY table that can obtain a two-dimensional motion by synthesizing two orthogonal linear motions and the carrier holder 22 can be integrated and moved, one eccentric arm 24 can be moved. By driving, the carrier holder 22 can be circularly moved without rotating. That is, by being guided by guides extending on two orthogonal axes of the XY table, the moving body does not rotate, and the movement of the moving body is changed to the movement of the carrier holder 22 (circular movement not rotating). It can be suitably used.
Further, without using the eccentric arm 24, the movement can be achieved by utilizing (controlling) the driving means of the XY table, for example, a driving mechanism comprising a servo motor and a timing chain or a ball screw disposed on each of the X axis and the Y axis. It is also possible to move the carrier holder 22 integrated with the body (a circular motion that does not rotate). In this case, two motors are used. By controlling the motors, various two-dimensional movements that do not rotate can be obtained in addition to the circular movements, and the movements are used for polishing the wafer 10. it can.
[0024]
Reference numeral 36 denotes a lower surface plate rotation motor, which is a power device for rotating the lower surface plate 16. For example, a geared motor can be used as in this embodiment, and its output shaft may be directly connected to the rotating shaft of the lower surface plate 16.
38 is a power means for rotating the upper surface plate, and rotates the upper surface plate 14. If the lower platen rotation motor 36 and the upper platen rotation power means 38 can freely change the rotation direction and rotation speed, they can flexibly respond to various polishing specifications.
In this double-side polishing apparatus, the wafer 10 disposed in the through-hole 12a of the carrier 12 is sandwiched between the upper surface plate 14 and the lower surface plate 16 as shown in FIG. . At this time, the force with which the wafer 10 is pinched is mainly due to a pressurizing means (not shown) provided on the upper surface plate 14 side . Note that the pressure applied to the wafer 10 by the upper surface plate 14 may be adjusted by an air bag method using air pressure. The pressure can be adjusted suitably and easily by controlling the air pressure. In addition to the pressurizing means, an elevating device 40 for elevating and lowering the upper surface plate 14 is provided on the upper surface plate 14 side, and operates when the wafer 10 is supplied and discharged.
[0025]
Next, a reference example of a seasoning tool (correcting member) will be described in detail with reference to FIGS. FIG. 1A is a plan view showing the carrier 12 holding the wafer 10 and the correction member 15, and FIG. 1B is a cross-sectional view of FIG.
The correction member 15 is formed to have a thickness equivalent to that of the wafer 10 as a workpiece, is held together with the wafer 10 on the carrier 12, and simultaneously with the double-side polishing process of the wafer 10, both polishing surfaces 14a of the upper and lower surface plates 14, 16 are provided. 16a is corrected.
The correction member 15 is formed in a plate shape and is disposed and held in a correction member through-hole 13 provided in a portion of the carrier 12 where the wafer 10 is not held. That is, a hole (through hole 12a) for inserting the wafer 10 into the carrier 12 is opened, and another hole (through hole 13 for a member for correction) is opened between the holes. A seasoning tool (correcting member 15) is inserted. Thereby, the correction mechanism of the grinding | polishing surfaces 14a and 16a can be comprised easily and suitably .
[0026]
Thus, by arranging the correcting member 15, the polishing surfaces 14a and 16a can be corrected simultaneously with the polishing step of the wafer 10, and the state of the polishing surfaces 14a and 16a is changed as shown in FIG. It can be kept flat and constant. 2A is a cross-sectional view showing a state before starting the polishing step, and FIG. 2B is a cross-sectional view showing a state after performing the polishing step, but the polishing surfaces 14a and 16a are uniform. The wafer 10 is polished flat.
Therefore, it is possible to improve the polishing accuracy of the wafer (work), and it is not necessary to perform a correction process separately, so that the processing efficiency can be improved.
Further, the use of the correction member 15 has an advantage that the carrier can be simplified without being divided into a carrier for holding the workpiece and a carrier for correcting the polishing surface.
[0027]
Next, such an embodiment of the present invention will be described with reference to FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view.
The correcting member 55 of the present embodiment is disposed and held in a large through-hole 53 formed larger than the through-hole 12a in which the work (wafer 10) of the carrier 12 is held, and is provided on the inner peripheral portion. It has a ring shape in which a through hole 55a for holding the wafer 10 is formed.
With this configuration, the same effect as described above can be obtained.
The correction members 15 and 55 used above may be made of an inexpensive glass material or ceramic material, and does not increase the manufacturing cost.
[0028]
Next, an example of how to use the double-side polishing apparatus according to the present invention will be described.
First, the case where the upper surface plate 14 and the lower surface plate 16 are rotated in the opposite direction with the same absolute value of the rotation speed without moving the carrier 12 will be described. That is, as shown in FIG. 3, for example, the upper surface plate 14 rotates clockwise and the lower surface plate 16 rotates counterclockwise. In this case, since frictional force acts in exactly the opposite direction, the kinetic forces cancel each other, and theoretically, both surfaces are polished while the wafer 10 is stopped. However, in this case, the peripheral speed of the upper surface plate 14 and the lower surface plate 16 increases toward the outer periphery. Therefore, the polishing is promoted at a portion farther from the portion corresponding to the axis L of the upper and lower surface plates 14 and 16 of the wafer 10, and the wafer 10 is not uniformly polished.
[0029]
Next, the polishing action by causing the carrier 12 to perform a circular motion that does not rotate by the motion mechanism having the above-described configuration will be described.
If only the circular motion of the carrier 12 that does not rotate without considering the rotation of the upper and lower surface plates 14 and 16 is considered, the circular motion that does not rotate is exactly the same in all points of the moving member (carrier 12). Exercise will be done. This is a kind of oscillating motion in the sense that all the points have the same motion, and it can be considered that the locus of the oscillating motion is a circle.
Therefore, if the wafer 10 is swung through the carrier 12 that does not rotate and moves in a circular motion, both surfaces of the wafer 10 are uniformly polished if the action is limited to this motion.
[0030]
When the rotational motion of the upper surface plate 14 and the lower surface plate 16 and the circular motion of the carrier 12 that does not rotate are operated simultaneously, the wafer 10 is held rotatably in the through hole 12a. When the absolute values of the rotational speeds of the upper surface plate 14 and the lower surface plate 16 are different (when the rotational speed of the other surface plate is increased with respect to one surface plate), the wafer 10 has a higher rotational speed. Rotate in the direction of rotation of the side platen. That is, the wafer 10 rotates in a predetermined direction.
As the wafer 10 rotates in this manner, the upper surface plate 14 and the lower surface plate 16 increase in peripheral speed toward the outer periphery, but the influence can be eliminated and the wafer 10 is polished uniformly. it can.
In addition, in order to polish both surfaces of the wafer 10 uniformly, the rotational speeds of the upper surface plate 14 and the lower surface plate 16 may be controlled so that one of them alternately increases.
[0031]
Next, another example of how to use the double-side polishing apparatus according to the present invention will be described.
In the above embodiment, a case where a plurality of through holes 12a are provided and a plurality of workpieces (wafers 10) are simultaneously polished has been described. However, the present invention is not limited to this. For example, the carrier 12 has a large workpiece. Only one through hole 12a to be held can be provided and used as a polishing apparatus for polishing both surfaces of the large workpiece. In addition, as a large sized workpiece | work, there exists a workpiece | work, such as a rectangular glass plate used for a liquid crystal, or a wafer (circular shape) processed with a sheet.
In this case, the large workpiece is disposed almost entirely from the center of the carrier 12 to the vicinity of the periphery thereof. At this time, if polishing is performed mainly using the circular motion that does not rotate by the carrier 12, and the rotational speeds of the upper surface plate 14 and the lower surface plate 16 are slowed to such an extent that uneven polishing does not occur, the entire surface of the workpiece is uniform. And it can grind | polish suitably. That is, the upper surface plate 14 and the lower surface plate 16 have a larger polishing action at the outer periphery due to the difference in peripheral speed, but if the rotation speed is very slow compared to the circular motion of the carrier 12 that does not rotate, the polishing action is directly affected. Can be hardly involved. Then, rotating the upper surface plate 14 and the lower surface plate 16 always updates the surface plate surface in contact with the workpiece, and in order to improve the polishing action such as supplying a liquid abrasive to the entire surface of the workpiece on average. It can contribute indirectly and favorably.
[0032]
In the above embodiment, the case where the carrier 12 and the carrier holder 22 connected together by the connecting means 50 and the carrier holder 22 are provided with the carrier circular motion mechanism 20 so as to perform a circular motion that does not rotate has been described. However, the movement mechanism applied to the carrier 12 and the carrier holder 22 that move together may be selectively set as appropriate. For example, the present invention can also be suitably applied to a case where a movement mechanism that rotates the carrier 12 and the carrier holder 22 that move together and reciprocates linearly is provided.
[0033]
Although the polishing apparatus has been described in the above embodiment, it is needless to say that the present invention can be suitably applied to a wrapping apparatus.
As described above, the present invention has been described in various ways with reference to preferred embodiments. However, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. That is.
[0034]
【The invention's effect】
According to the double-side polishing apparatus of the present invention, the correction member is formed in a ring shape that has a larger diameter than the work and can accommodate the work, and the through hole of the carrier has a size that can accommodate the correction member. Since the correction member is accommodated in the through hole of the carrier and the workpiece is accommodated in the correction member for polishing the workpiece, the upper and lower surfaces of the workpiece are simultaneously polished. Both polishing surfaces of the surface plate can be corrected , and the state of the polishing surface formed by a cloth or the like can be kept constant.
For this reason, the polishing accuracy of the workpiece can be improved, the time for the correction process can be omitted, and the operating rate of the polishing apparatus can be improved.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a reference example of a correction member .
FIG. 2 is a cross-sectional view showing the operation of the embodiment of FIG.
FIG. 3 is a perspective view showing an embodiment of the entire double-side polishing apparatus according to the present invention.
4 is a cross-sectional view showing the embodiment of FIG. 3;
FIG. 5 is an explanatory view showing an embodiment of a means for linking a carrier and a carrier holder.
FIG. 6 is an explanatory view showing an example of a correction member according to the present invention.
FIG. 7 is an explanatory diagram explaining the background art.
FIG. 8 is a cross-sectional view for explaining the operation of the background art.
FIG. 9 is an explanatory diagram for explaining another background art.
FIG. 10 is a cross-sectional view for explaining the operation of another background art.
FIG. 11 is a cross-sectional view illustrating a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Wafer 12 Carrier 12a Through-hole 12b Hole 13 Correction member through-hole 14 Upper surface plate 14a Polishing surface 15 Correction member 16 Lower surface plate 16a Polishing surface 20 Carrier circular motion mechanism 22 Carrier holder 23 Pin 23a Flange portion 23b Screw portion 24 Eccentric arm 24a Holder-side shaft 24b Base-side shaft 28 Timing chain 30 Base 50 Linking means 55 Correction member

Claims (4)

A carrier having a thin plate provided with a through hole, and a polishing surface for sandwiching a plate-like workpiece disposed in the through hole of the carrier from above and below and moving relative to the workpiece to polish the workpiece. An upper and lower surface plate, and a movement mechanism for moving the carrier in a plane parallel to the surface of the carrier and moving the work held between the upper and lower surface plates in the through hole; A correction member that is formed to have a thickness equivalent to that of the workpiece, is held together with the workpiece on the carrier, and corrects both polishing surfaces of the upper and lower surface plates simultaneously with a double-side polishing step of the workpiece ;
The correction member is formed in a ring shape having a larger diameter than the work and capable of accommodating the work inside,
The through hole of the carrier is formed into a through hole having a size capable of accommodating the correction member,
A double-side polishing apparatus characterized in that the correction member is accommodated in a through hole of the carrier, and the workpiece is accommodated in the correction member to polish the workpiece .   The movement mechanism causes the carrier to make a circular movement that does not rotate in a plane parallel to the surface of the carrier, and to turn and move the work held between the upper and lower surface plates in the through hole. The double-side polishing apparatus according to claim 1, wherein the double-side polishing apparatus is a circular motion mechanism. The carrier circular movement mechanism includes a carrier holder for holding the carrier, a holder-side axis parallel to the axis of the upper and lower surface plates, and a holder-side axis and parallel to the holder-side axis. A base-side shaft that is pivotally attached to the base at a predetermined distance is provided, and the holder-side shaft is pivoted about the base-side axis so that the carrier holder makes a circular motion that does not rotate with respect to the base. 3. The double-side polishing apparatus according to claim 2 , further comprising: an eccentric arm; and a rotation driving device that rotates the eccentric arm about a base-side axis. The eccentric arm provided with a plurality, as eccentric arm of said plurality of the circular motion in synchronism, according to claim 3, wherein the axial ends of the base side is cooperative by the synchronization means such as a timing chain Double-side polishing equipment.

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