JP4805664B2 - Semiconductor wafer front / back edge simultaneous polishing apparatus and front / back edge simultaneous polishing method - Google Patents

Description

  The present invention relates to an edge polishing apparatus for a semiconductor wafer, and more particularly to a polishing apparatus and a polishing method capable of simultaneously polishing the front and back edges thereof.

  A semiconductor wafer has a disk shape and has a pattern forming surface, its back surface, side surface, edge, and notch or orientation flat (orientation flat), and these portions are usually polished by different dedicated polishing apparatuses. .

  The edge is an inclined surface formed on the front and back surfaces around the semiconductor wafer, and several polishing methods or apparatuses have been developed for polishing the edge. Among these polishing methods or apparatuses, there is known one that polishes an edge by pressing a semiconductor wafer against a polishing tool having a polishing pad affixed inside a spherical surface. Patent Documents 1 to 9 disclose such a technique.

  With the exception of Patent Document 7, any of the techniques disclosed therein can polish only the edge on one side at the same time. In order to polish the front and back edges, after the polishing of one edge is completed, it is necessary to reverse the semiconductor wafer or to polish the other edge with another polishing tool facing in the opposite direction. For this reason, two polishing steps are inevitably required to polish the front and back edges. Further, in the technique disclosed in Patent Document 7, although the front and back surfaces are simultaneously polished, the polishing portion is almost on the opposite side across the center of the semiconductor wafer.

  Furthermore, in such a prior art, the semiconductor wafer receives a pressing force from only one direction by the polishing tool. This causes the following problems.

  (A) A bending moment M as shown in FIG. 13 is applied to the overhang portion of the semiconductor wafer. A semiconductor wafer is a brittle material and has a property of being easily broken (easy to break). Therefore, the pressing force applied to the polishing tool in order to generate the polishing pressure is limited, and furthermore, since the contact is made in a wide area and the heat radiation is bad, the size of the polishing pressure can be set so freely. Can not.

  (B) Further, since the polishing tool is in contact with the entire circumference of the semiconductor wafer (however, the one of Patent Document 6 is not the “entire circumference”), when trying to maintain the polishing pressure per unit area at a predetermined value, The pressing force must be increased. When polishing the back side edge without changing the semiconductor wafer, this pressing force acts in the direction of peeling the semiconductor wafer, so a particularly large adsorption force is required so that the semiconductor wafer can be supported without dropping by this pressing force. It becomes. In addition, when carrying over, this is not preferable in the sense that the suction mark remains on the pattern forming surface.

  (C) Further, as described above, the semiconductor wafer tends to bend due to the bending moment, but apart from the above-described cracking problem, a large contact pressure (contact) is also generated at the portion contacting the periphery of the table supporting the semiconductor wafer due to this moment. Pressure).

  (D) The back surface of the semiconductor wafer is likely to be damaged by the adsorption force or the partial high surface pressure (contact pressure).

  (E) In the conventional one, the edge is polished sequentially for each side, that is, the front and back of the edge are not polished simultaneously. However, as described above, in the technique disclosed in Patent Document 7, although the front and back surfaces are simultaneously polished, the polishing portion is almost on the opposite side across the center of the semiconductor wafer. In any case, at the time of polishing, there is nothing on the opposite side of the edge to be polished, so that it can be displaced in that direction. Therefore, chatter is likely to occur, and when the chatter occurs, the polished surface becomes rough, and a predetermined surface quality may not be obtained.

Japanese Patent Laid-Open No. 10-029142 Japanese Patent Laid-Open No. 11-010500 Japanese Patent Laid-Open No. 11-070450 JP 2000-317788 A JP 2002-036079 A JP 2002-137155 A JP 2003-145398 A JP 2003-145399 A JP 2003-175446 A

  The present invention solves the problem of cracking due to moment, the problem of scratches in contact with the table, and the problem of roughness of the polished surface due to chatter as described above, and the prior art requires two steps. It is another object of the present invention to make it possible to polish the front and back edges in a single process and not to require a large force when adsorbing a semiconductor wafer.

  In the present invention, two opposing polishing tools are used, and the front and back edges are simultaneously polished by each tool. As a result, the pressing force applied to the semiconductor wafer by each polishing tool is canceled as a whole, so that a force that deforms (bends) the semiconductor wafer as a whole does not work.

  Before describing the problem solving means of the present invention, the outline of the principle of the present invention will be described based on FIG. FIG. 1 is an explanatory diagram depicting a state where two spheres intersect. When the spheres a and b intersect, a circle (disk) c appears at the intersection. In the vicinity of the intersecting portion, the spheres a and b and the circle (disk) c intersect with an inclination α according to the diameter of the sphere and the mutual positional relationship. For simplicity of explanation, the spheres a and b are shown as having the same diameter, but these diameters may be different from each other.

  As is well known, the semiconductor wafer has a disk shape, and an inclined surface, that is, an edge is formed on the front and back of the circumferential portion. Therefore, assuming that this disk c is a semiconductor wafer, and the inside of the spheres a and b are regarded as the polishing surface of the polishing tool, and the semiconductor wafer and the polishing tool can be given an appropriate relative motion, the inclination α can be determined. The edges it has can be polished at the same time.

  The polishing tool in the prior art described above has a bowl-like shape, and its periphery is continuous without a break. For this reason, the two edges can be simultaneously polished only in such a manner that the edge portions of the two identical scissors-like polishing tools are abutted at positions around the semiconductor wafer.

  However, in this case, the place where the polishing tool is in contact with the edge is always the same place, and only that place is worn out violently, so it is not practical.

  In the above prior art, the rotation axis of a single polishing tool and the rotation axis of the semiconductor wafer are inclined with respect to each other so that the contact point moves on the inner spherical surface as the polishing surface of the polishing tool rotates. Distributes wear points and extends tool life. However, as described above, it is possible only with one polishing tool, and it is not possible to simultaneously polish the front and back edges using two polishing tools.

  Note that the polishing apparatus of Patent Document 5 includes two polishing tools, but the two polishing tools do not polish at the same time, and the polishing process for the upper and lower surfaces of the edge acts as a polishing tool. There is only one in each.

  In the present invention, as shown in FIGS. 2 and 3 to be described later, the polishing surface of the polishing tool is divided into a plurality of parts and spaced apart from each other, and the polishing surface of one polishing tool is the other polishing tool. A pressing force is applied so as to face each other between the polishing surfaces, and the rotation axes of the two polishing tools are rotated and driven. The semiconductor wafer is placed in a space created by opposing polishing tools and is also driven to rotate.

  And the said subject is solved by the following means. That is, the problem-solving means of the first invention is a plurality of pad blocks in which the surface of the affixed polishing pad forms an inner partial spherical surface of a virtual spherical surface, and the inner partial spherical surface of each of the pad blocks is the virtual spherical surface. A first polishing plate in which the pad block is arranged at intervals along the circumference, the inner partial spherical surface of the pad block is in contact with the phantom spherical surface, and A second polishing plate in which the pad blocks are arranged at intervals along the circumference; a work table for supporting a disk-shaped semiconductor wafer; a table shaft that supports and rotates the work table; and the table A table shaft rotational drive device for rotationally driving the shaft, the center of the phantom spherical surface of the first polishing plate on the rotational center line of the table shaft; And a first polishing plate head for supporting the first polishing plate so as to be rotatable about a straight line inclined with respect to the rotation center line of the table shaft, and on the rotation center line of the table shaft , The center of the phantom spherical surface of the second polishing plate is placed on the first polishing plate, and the straight line inclined with respect to the rotation center line of the table shaft is rotatable about the rotation center. A second polishing plate head that supports the second polishing plate, a pad block of the first polishing plate, and a pad block of the second polishing plate are mutually other so as to face the second polishing plate A plate rotation drive device that rotationally drives the two polishing plates while maintaining a phase that does not interfere with each other between the pad blocks. A press feed device for feeding the first polishing plate head and the second polishing plate head along the direction of the rotation center line of the table shaft so as to relatively approach and separate from each other, and a semiconductor on the work table A through hole provided in one of the two polishing plates so that the table shaft can pass therethrough in order to rotate the wafer in a space between the two polishing plates; and a polishing unit A device for simultaneously polishing front and back edges of a semiconductor wafer, comprising a polishing liquid supply device for supplying a polishing liquid to the semiconductor wafer.

  According to a second aspect of the present invention, there is provided a semiconductor wafer front and back edge simultaneous polishing apparatus according to the first aspect, wherein the first polishing plate head is fixed to a machine base, and the press feed device is the first polishing apparatus. 2 is a device for simultaneously polishing front and back edges of a semiconductor wafer, which is for feeding two polishing plate heads.

  According to a third aspect of the present invention, there is provided a semiconductor wafer front and back edge simultaneous polishing apparatus according to the second aspect, wherein the table shaft is axially moved in order to move the workpiece between the attachment / detachment position and the polishing position. A device for simultaneously polishing front and back edges of a semiconductor wafer, comprising a table feeding device for feeding.

  According to a fourth aspect of the present invention, there is provided a semiconductor wafer front / back edge simultaneous polishing apparatus according to any one of the first to third inventions, wherein the press feed device is located on a machine base and the first polishing plate head. And a semiconductor wafer front and back edge simultaneous polishing apparatus for feeding a second polishing plate head.

According to a fifth aspect of the present invention, there is provided a semiconductor wafer front / back edge simultaneous polishing apparatus according to any one of the first to fourth inventions, wherein the table axis is disposed in a horizontal direction. This is a device for simultaneously polishing front and back edges of a semiconductor wafer.

SUMMARY OF sixth invention, in the front and back edges simultaneous polishing apparatus of a semiconductor wafer of the invention from the first to fourth, and wherein said table shaft is arranged so as to face the vertical direction This is a device for simultaneously polishing front and back edges of a semiconductor wafer.

  According to a seventh aspect of the present invention, there is provided a semiconductor wafer front / back edge simultaneous polishing apparatus according to any one of the first to sixth inventions, wherein the through hole is provided in the other of the two polishing plates. The semiconductor wafer front and back edge simultaneous polishing apparatus is characterized in that the nozzle of the polishing liquid supply device supplies the polishing liquid to the polishing portion through each through hole.

  According to an eighth aspect of the present invention, there is provided a semiconductor wafer front / back edge simultaneous polishing apparatus according to any one of the first to seventh aspects of the invention, wherein at least during polishing, the work table has a rotational axis of the table shaft. The front and back edges of a semiconductor wafer are characterized in that they can be freely displaced by the bias of the force applied to the semiconductor wafer with respect to at least one of the position in the direction, the position in the radial direction, and the inclination with respect to the rotation axis. It is a simultaneous polishing device.

  According to a ninth aspect of the present invention, there is provided a semiconductor wafer front and back edge simultaneous polishing apparatus according to the eighth aspect, wherein the work table is supported by the table shaft via a flexible member. An apparatus for simultaneously polishing front and back edges of a semiconductor wafer, characterized in that said free displacement is possible.

  According to a tenth aspect of the present invention, in the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to the first to ninth aspects of the invention, the first polishing plate and the second polishing plate are provided. The pad block has a plurality of pad blocks arranged at intervals along the circumference of each polishing plate, and the plate rotation driving device rotates and drives these two polishing plates at an equal speed. The semiconductor wafer front and back edge simultaneous polishing apparatus.

  According to an eleventh aspect of the present invention, there is provided a plurality of pad plates in which a plurality of pad blocks in which a surface of a polishing pad forms an inner partial spherical surface of an imaginary spherical surface are arranged at intervals along the circumference, The polishing pad side faces each other, and the semiconductor wafer disposed therebetween is pressed by being sandwiched between two polishing plates, and the pad block of the one polishing plate is the other polishing plate The semiconductor wafer is rotated around its central axis while maintaining the position between the two pad blocks, and each of the two rotation axes inclined opposite to each other with respect to this axis is A method for simultaneously polishing front and back edges of a semiconductor wafer, wherein the polishing plate is rotated.

  According to the semiconductor wafer front and back edge simultaneous polishing apparatus and method of the present invention, the front and back edges of the semiconductor wafer can be polished at the same time, so that the conventionally required two polishing steps can be made one step.

  Further, since the semiconductor wafer is simultaneously subjected to the polishing pressure from both the front and back surfaces by the simultaneous polishing of the front and back surfaces, the force applied to the entire semiconductor wafer is offset. For this reason, since the bending moment which breaks this is not applied to the semiconductor wafer, the polishing pressure can be selected in a wide range.

  Since the force applied to the entire semiconductor wafer is canceled (balanced), the force to peel off the adsorbed semiconductor wafer does not work, so that it can be held with a small adsorbing force. As a result, the contact pressure at the contact portion between the work table and the surrounding area can be lowered, and thus it is possible to prevent the back surface from being damaged. Further, since it is not necessary to change the semiconductor wafer, no suction mark is left on the pattern forming surface.

  At the time of polishing, both are simultaneously polished, so that the occurrence of chatter is suppressed by the polishing tool, and it is possible to prevent the polishing surface from being rough and the surface quality from being deteriorated. In addition, a plurality of pad blocks, that is, polishing pads are arranged at intervals from each other, and focusing on one point on the front or back of the edge of the semiconductor wafer results in intermittent polishing, that is, polishing. Since the period and the non-polished period are alternated, the heat dissipation is much better than that of the conventional techniques as listed in the patent literature. Thus, the polishing pressure can be set in a wide range without causing deterioration of the polished surface.

  It is relatively easy to design the polishing apparatus so that polishing is performed with the semiconductor wafer upright, and the installation area can be reduced, so it is easy to cope with the trend of increasing the diameter of the semiconductor wafer. It can correspond to.

  Embodiments of the present invention will be described below with reference to the drawings.

* Outline of Polishing Apparatus 1 FIG. 4 and FIG. 5 are cross-sectional views of the semiconductor wafer front and back edge simultaneous polishing apparatus 1 of the present invention, and an example thereof will be described. FIG. 4 shows a state in which the two polishing plate heads 4 and 5 are being brought close to each other, and FIG. 5 shows a state in which the two polishing plate heads 4 and 5 are separated and the workpiece is loaded and discharged.

  The semiconductor wafer front and back edge simultaneous polishing apparatus 1 includes a machine base 2, a work head 3, and two polishing plate heads 4 and 5.

  The work head 3 is fixed to the machine base 2 and supports the table shaft 31 rotatably. A work table 32 is fixed to one end of the table shaft 31, and a semiconductor wafer W (or simply called a work W) is sucked and held on the work table 32. In the case of the embodiment, since the table shaft 31 is horizontally oriented, the front and back surfaces of the workpiece W are supported in a vertical plane.

  A suction hole 311 passes through the table shaft 31, one end of the suction hole 311 is connected to a vacuum chuck (not shown) portion of the work table 32, and the other end is used for suction from a vacuum source 36. The vacuum is supplied.

  A pulley 33 is fixed near the other end of the table shaft 31. The machine base 2 is provided with a motor M1, and a pulley 34 is fixed to the output shaft of the motor M1. A belt 35 is stretched between the pulley 33 and the pulley 34. The rotation of the motor M1 is transmitted to the pulley 34, the belt 35, and the pulley 33, and the work table 32 fixed to the table shaft 31 rotates. A table shaft rotation drive device is formed by the motor M1, the pulleys 33 and 34, and the belt 35.

  The polishing plate heads 4 and 5 are placed on a linear guide 21 provided on the machine base 2. The guide direction of the linear guide 21 is parallel to the table shaft 31. The polishing plate heads 4 and 5 face each other across the work table 32, and the pressure receiving member 56 below the polishing plate heads 4 and 5 is pushed by the piston cylinder mechanisms 22 and 23 provided on the machine base 2. Press feed is possible. Accordingly, the polishing plate heads 4 and 5 can move toward and away from each other about the work table 32 as a center.

  The pressure medium used in the piston / cylinder mechanisms 22 and 23 can be either pressurized air or hydraulic pressure. However, in consideration of the environment where this apparatus is installed, it is easy to obtain pressurized air. It is preferable to use pressurized air because it does not pollute the surroundings due to the leakage of air, and the air is compressible and has a resilient pressing force, which is suitable for applying polishing pressure. I can say that.

* Detailed structure of the polishing plate heads 4 and 5 Since the two polishing plate heads have the same structure, the structure will be described in more detail with reference to FIG. 6 where the polishing plate head 5 (right side) portion is taken out.

  The polishing plate head 5 includes a head main body 51, a polishing plate 52 rotatably supported by the head main body 51, and a polishing liquid supply device 53. The rotation axis of the polishing plate 52 is inclined with respect to the table shaft 31 by an axis inclination angle β.

  The polishing plate 52 has a ring shape as a whole, and is similarly provided with a ring-shaped drive plate 521. An internal gear 522 is provided inside the ring of the drive plate 521. A pinion gear 523 fixed to the output shaft of the motor M2 meshes with the internal gear 522. By rotating the motor M2, the polishing plate 52 is rotationally driven via the pinion gear 523 and the internal gear 522. A plate rotation drive device is formed by the motor M2, the pinion gear 523, and the internal gear 522.

  The motor M2 is rotationally driven in synchronism with another motor M3 provided in another polishing plate head 4. Thereby, each polishing plate of the two polishing plate heads 4 and 5 rotates synchronously. However, as will be described later, the rotation directions thereof are opposite to each other. In other words, the circumferential speed and the direction of the two polishing plates 52 are the same when facing each other.

  Then, the phases of the two motors M <b> 2 and M <b> 3 are controlled so that the pad block 54 of the one side polishing plate 52 is positioned between two adjacent pad blocks 54 of the other side polishing plate 52. As the motors M2 and M3, motors that can easily control the phase and synchronization, for example, stepping motors, can be used, but other types of motors can be used as long as they can.

  A plurality of pad blocks 54 are arranged on the front surface of the polishing plate 52 at intervals along the circumference, as shown in an enlarged view in FIG. A polishing pad 541 is affixed to each pad block 54, and the surface of the affixed polishing pad 541 just forms an inner partial spherical surface Sp of the phantom spherical surface S. The virtual spherical surface S corresponds to the spheres a and b described above.

  The polishing liquid supply device 53 includes a ring nozzle 531, a pipe 532 that guides the polishing liquid into the pipe body of the ring nozzle 531 and supports the ring nozzle 531, and a support box 533 that supports the pipe 532. The support box 533 is supplied with a polishing liquid from an external supply source (not shown).

  The ring nozzle 531 is a donut-shaped tube body. A large number of nozzle holes 5311 are opened on the side surface of the tube, and the polishing liquid is sprayed toward the polishing portion.

  Sliding surfaces 55 are formed at appropriate portions of the polishing plate head 5, so that the polishing plate head 5 can slide on the linear guide 21.

  Returning to FIG. 4 and FIG. 5, the description of the operation of this apparatus will be continued. As already described, substantially the same polishing plate head 5 is disposed as the polishing plate head 4 so as to face each other.

  When the polishing plate heads 4 and 5 are respectively sent to the left and right feed ends (FIG. 5) after being sent by the piston / cylinder mechanisms 22 and 23, they are largely separated from each other, and a space is formed between them. If the polishing of the edge is finished, the semiconductor wafer W adsorbed on the work table 32 is gripped by a handling device (not shown) inserted into this space and carried out of the device. Thereafter, a new semiconductor wafer is carried from outside the apparatus by the handling apparatus and is attracted to the work table 32.

  Next, the motor M1 is driven, the semiconductor wafer W starts to rotate, and is sent in a direction in which the polishing plate heads 4 and 5 approach each other by the piston cylinder mechanisms 22 and 23, and each polishing plate 52 is moved by the motors M2 and M3. Start spinning. At an appropriate time, the supply of the polishing liquid from the polishing liquid supply apparatus 53 is also started.

  When the polishing plate heads 4 and 5 are continuously fed in the approaching direction with the semiconductor wafer interposed therebetween, the pad block 54 of the polishing plate 52 on one side is positioned between two adjacent pad blocks 54 of the polishing plate 52 on the other side. Therefore, the pad blocks 54 do not collide with each other.

  Eventually, each polishing pad 541 comes into contact with each edge of the semiconductor wafer W as shown in FIG. 3A and a partially enlarged view thereof, and polishing starts. The piston-cylinder mechanisms 22 and 23 are opposite in direction and set so as to give the same pressing force to each other, so that the forces applied to the front and back edges are balanced. For this reason, the force which bends the semiconductor wafer W does not work. During polishing, the two polishing plates 52 are kept in their rotational phase and speed, so that the partner pad block 54 is rotated without interfering with each other.

  The rotating shaft of the polishing plate 52 is inclined with respect to the table shaft 31 by the axis inclination angle β as described above. For this reason, as shown in FIG. 3A, in the lower part of the figure, the polishing pad 541 contacts the semiconductor wafer W on the side close to the center of the polishing plate 52, and in the upper part, the polishing pad 541 is in contact with the polishing plate 52. The side away from the center of the wafer is in contact with the semiconductor wafer W.

  As can be seen from this, the location where the polishing pad 541 performs the polishing action changes as the polishing plate 52 rotates. As a result, the worn portions of the polishing pad 541 are dispersed, and a long life is achieved. 2 and 3, the wear part (polishing part) is indicated by the symbol P.

  When the semiconductor wafer W is rigidly attached to the work table 32, when there is a slight error in the position where the semiconductor wafer W is attracted due to positioning errors of the transfer device, the semiconductor wafer W is polished during polishing. A large force is periodically applied locally from the plate 52. The same applies to the case where the rotational axis of the polishing plate 52 is slightly shifted. This causes breakage of the semiconductor wafer, deterioration of the surface quality, and the like. To avoid this, it is preferable that the work table 32 be displaceable with respect to the table shaft 31.

  In FIG. 7, the example of the support structure of the work table 32 which accept | permits such a displacement is shown. In the center of the work table 32 opposite to the work support surface, a flexible block 321 made of an elastic material made of rubber or synthetic resin is provided around the wall surface of the hole provided in the work table 32 and the inner surface of the ring hole. It is fixed to the table shaft 31 with an adhesive or the like.

  With this structure, when the work table 32 receives an unbalanced load in the direction of the table shaft 31, a moment that tilts the work table 32, or an unbalanced load in the radial direction of the work table 32, FIGS. ) And (c) are allowed to be displaced.

  FIG. 9 shows another example of the support structure of the work table 32 that allows displacement. The table shaft 31 is divided into two parts and these are connected by a coil spring 322. Each suction hole 311 is coupled by a stretchable and flexible pipe 323 such as a rubber, a synthetic resin tube, or a bellows, and displacement similar to that shown in FIG. 8 is allowed. In this case, since the semiconductor wafer W can rotate around its own center, no problem occurs.

  As a result, even when a biased force is applied to the semiconductor wafer for some reason, the force is absorbed by these displacements, so that the semiconductor wafer is prevented from being damaged or unevenly polished.

  Regarding the polishing liquid supply device 53, the example in which the ring nozzle 531 is first used is shown, but FIG. 10 shows another example. In the polishing liquid supply device 53, a nozzle 534 is provided in the pad block 54 or the polishing plate 52. The polishing liquid is guided from the outside to the polishing plate 52 through a fluid coupling (not shown), and is guided to the nozzle 534 through the inside or further inside the pad block 54. The sprayed polishing liquid once collides with the semiconductor wafer W or is directly supplied to the polishing unit.

  The polishing plate 52 may be assembled with a separate pad block 54 or may be formed integrally with the pad block 54.

  Further, the size, shape, and number of the pad blocks 54 may be any as long as the pad blocks 54 do not interfere with the pad blocks 54 of the mating polishing plate 52 during polishing. For example, as shown in FIG. 12 (a), two pad blocks 54 are provided on one polishing plate 52, or four as shown in FIG. 12 (b), or more. Can do. The shape can also be a rectangle or other shapes instead of the sector shape shown in this figure. In any case, the area where one polishing plate 52 hits the edge of the semiconductor wafer cannot exceed one half of the entire circumference, that is, the range of 180 degrees.

  The pair of covers 59 provided on the polishing plate heads 4 and 5 are for preventing the polishing liquid from splashing outside the apparatus during polishing, and are fixed to the respective polishing plate heads 4 and 5. However, it can also be made movable by any driving means.

  In the first embodiment described above, the two polishing plate heads 4 and 5 are both movable, and the work table 32 is not provided with a feeding device. However, these are relative. Therefore, one polishing plate head 4 or 5 is fixed to the machine base (or integrated with the machine base), and the polishing plate 52 and the semiconductor wafer W do not interfere with each other when the semiconductor wafer W is discharged and loaded. It is also possible to provide the table feeding device 6 on the table shaft 31 that supports the work table 32. FIG. 11 shows an example of such a front and back edge simultaneous polishing apparatus 1.

  In this example, the table feeder 6 includes a slide surface 61 fixed to the machine base 2, a slide body 62 that supports the table shaft 31 and slides thereon, and a piston cylinder mechanism for feeding the slide body 62 that slides. 63.

  In order to make the table shaft 31 free to move in the axial direction during polishing, it is preferable to provide a constraint releasing means for releasing the constraint between the table shaft 31 and the table feeding device 6. The release by the constraint release means is to switch and open the two ports of the piston cylinder mechanism 63, whereby the constraint release means can be easily realized.

  In this way, by making the table shaft 31 free with respect to the axial movement, the work table 32 can be moved even when a load is biased from one polishing plate 52 during polishing due to an error during loading of the semiconductor wafer W or the like. Since it floats and escapes to the balance point, the semiconductor wafer W is not immediately subjected to an unbalanced load. As a result, the forces received by the semiconductor wafer W from the two polishing plates 52 are canceled out. Regarding the other structure or operation of the polishing apparatus 1, the description of the previous example is used, and further description is omitted.

  So far, an example in which the table shaft 31 is horizontal (that is, the surface of the semiconductor wafer is vertical) has been shown, but it is naturally possible to make the table shaft 31 in the vertical direction.

As is clear from the above-described examples, in summary, in the present invention, the front and back edge simultaneous polishing of the semiconductor wafer is performed as follows. That is,
(1) Two polishing plates 52 in which a plurality of pad blocks 54 in which the surface of the polishing pad 541 forms an inner partial spherical surface Sp of the phantom spherical surface S are arranged along the circumference are arranged on the polishing pad 541 side. The semiconductor wafers W facing each other inward and pressed between the two polishing plates 52 are pressed.
(2) The semiconductor wafer W is rotated around its central axis while keeping the pad block 54 of one polishing plate 52 positioned between the pad blocks 54 of the other polishing plate 52.
(3) Each polishing plate 52 is rotated around each of two rotation axes inclined opposite to each other with respect to this axis.
(4) The above (1), (2), and (3) are performed simultaneously.

It is explanatory drawing for demonstrating the outline | summary of the principle of the simultaneous edge grinding | polishing apparatus of this invention. It is an enlarged view of the front surface of the polishing plate. (A) is explanatory drawing which shows the state which the polishing pad 541 is contacting each edge of the semiconductor wafer W, (b) is the elements on larger scale. It is sectional drawing of the semiconductor wafer front and back edge simultaneous grinding | polishing apparatus 1 of this invention, Comprising: The thing under grinding | polishing is shown. FIG. 2 is a cross-sectional view of the semiconductor wafer front / back edge simultaneous polishing apparatus 1 according to the present invention, showing the semiconductor wafer W being discharged and loaded. 3 is a cross-sectional view of a polishing plate head 5. FIG. It is sectional drawing explaining the support structure of the work table 32 which accept | permits a displacement. (A), (b), (c) is sectional drawing which shows the state which the work table 32 displaced. It is sectional drawing explaining another support structure of the work table 32 which accept | permits a displacement. 4 is an explanatory diagram for explaining an example in which a polishing liquid nozzle is provided on a pad block 54 or a polishing plate 52. FIG. It is sectional drawing which shows another example of the front and back edge simultaneous grinding | polishing apparatus 1. FIG. It is explanatory drawing for demonstrating the shape of the pad block attached to a grinding | polishing plate, number, and size. It is explanatory drawing for demonstrating that the bending moment M is applied to the overhanging part of a semiconductor wafer in the conventional edge grinding | polishing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front and back edge simultaneous grinding | polishing apparatus 2 Machine stand 21 Linear guide 22, 23 Piston cylinder mechanism 3 Work head 31 Table axis | shaft 311 Suction hole 32 Work table 321 Flexible block 322 Coil spring 323 Pipe 33, 34 Pulley 35 Belt 36 Vacuum source 4, DESCRIPTION OF SYMBOLS 5 Polishing plate head 51 Head main body 52 Polishing plate 521 Drive plate 522 Internal gear 523 Pinion gear 53 Polishing liquid supply apparatus 531 Ring nozzle 5311 Nozzle hole 532 Pipe line 533 Support box 534 Nozzle 54 Pad block 541 Polishing pad 55 Sliding surface 56 Pressure receiving Member 59 Cover 6 Feeder 61 Slide surface 62 Slide body 63 Piston cylinder mechanism M1, M2, M3 Motor M Moment a, b Sphere c Disk S Virtual spherical surface Sp Inner partial spherical surface W Semiconductor wafer (work)

Claims (11)

A plurality of pad blocks in which the surface of the affixed polishing pad forms an inner partial sphere of a virtual sphere
A first polishing plate in which the inner partial spherical surface of each of the pad blocks is in contact with the virtual spherical surface, and the pad blocks are arranged at intervals along the circumference;
A second polishing plate in which the inner partial spherical surface of each of the pad blocks is in contact with the virtual spherical surface, and the pad blocks are arranged at intervals along the circumference;
A work table for supporting a disk-shaped semiconductor wafer,
A table shaft that supports and rotates the work table,
A table shaft rotation drive device for rotating the table shaft;
The first polishing plate is arranged such that the center of the phantom spherical surface of the first polishing plate is placed on the rotation center line of the table shaft and is rotatable about a straight line inclined with respect to the rotation center line of the table shaft. A first polishing plate head for supporting a polishing plate of
The center of the phantom spherical surface of the second polishing plate is placed on the rotation center line of the table axis, and a straight line inclined with respect to the rotation center line of the table axis is rotatable about the rotation center. A second polishing plate head that supports the second polishing plate such that the second polishing plate faces the first polishing plate;
The two polishing plates are rotated while maintaining the phase where the pad block of the first polishing plate and the pad block of the second polishing plate are between the other pad blocks and do not interfere with each other. Plate rotation drive device to drive,
A pressure feeding device for feeding the first polishing plate head and the second polishing plate head along the rotation center line direction of the table shaft so as to relatively approach and separate from each other;
A through-hole provided in one of the two polishing plates so that the table shaft can pass therethrough in order to rotate the semiconductor wafer on the work table in a space between the two polishing plates. Holes and
A device for simultaneously polishing front and back edges of a semiconductor wafer, comprising a polishing liquid supply device for supplying a polishing liquid to a polishing portion. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to claim 1,
The apparatus for simultaneously polishing front and back edges of a semiconductor wafer, wherein the first polishing plate head is fixed to a machine base, and the press feeding device is for feeding the second polishing plate head. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to claim 2,
An apparatus for simultaneously polishing front and back edges of a semiconductor wafer, comprising a table feeding device for feeding the table shaft in an axial direction in order to move a workpiece between an attachment / detachment position and a polishing position. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to any one of claims 1 to 3,
The apparatus for simultaneously polishing front and back edges of a semiconductor wafer, wherein the press feeding device is for feeding the first polishing plate head and the second polishing plate head on a machine base. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to any one of claims 1 to 4,
An apparatus for simultaneously polishing front and back edges of a semiconductor wafer, wherein the table axis is disposed so as to face a horizontal direction. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to claims 1 to 4 ,
The apparatus for simultaneously polishing front and back edges of a semiconductor wafer, wherein the table axis is arranged so as to face a vertical direction. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to claims 1 to 6,
The through hole is also provided on the other of the two polishing plates, and the nozzle of the polishing liquid supply device supplies the polishing liquid to the polishing portion through each through hole. Simultaneous polishing equipment for semiconductor wafer front and back edges. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to any one of claims 1 to 7,
At least during polishing, the work table is biased in the force applied to the semiconductor wafer with respect to at least one of the position of the table shaft in the rotational axis direction, the position in the radial direction, and the inclination with respect to the rotational axis. An apparatus for simultaneously polishing the front and back edges of a semiconductor wafer, wherein the semiconductor wafer can be freely displaced. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to claim 8,
The apparatus for simultaneously polishing front and back edges of a semiconductor wafer, wherein the work table is supported by the table shaft via a flexible member, so that the free displacement is possible. In the apparatus for simultaneously polishing front and back edges of a semiconductor wafer according to any one of claims 1 to 9,
The pad blocks provided in the first polishing plate and the second polishing plate are arranged such that a plurality of pad blocks are arranged at intervals along the circumference in each polishing plate,
The above-mentioned plate rotation driving device rotates and drives these two polishing plates at an equal speed. Two polishing plates in which a plurality of pad blocks in which the surface of the polishing pad forms an inner partial spherical surface of the phantom spherical surface are arranged at intervals along the circumference face each other with the polishing pad side inward , While pressing so as to sandwich the semiconductor wafer disposed between the two polishing plates, and
While maintaining the pad block of the one polishing plate located between the pad blocks of the other polishing plate,
While rotating the semiconductor wafer around its central axis,
A method for simultaneously polishing front and back edges of a semiconductor wafer, wherein each of the polishing plates is rotated around each of two rotation axes inclined opposite to each other with respect to the axis.

Images