JP6660743B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding device, and more particularly, to a grinding device capable of grinding while tilting a wafer.

  In the field of semiconductor manufacturing, backside grinding of the backside of a wafer is performed in order to form a semiconductor wafer such as a silicon wafer (hereinafter, referred to as “wafer”) into a thin film.

  As a grinding device for grinding the back surface of a wafer, Patent Document 1 discloses a holding device for holding a wafer, a grinding device for grinding the wafer, a tilt angle adjusting device for adjusting the tilt of the holding device to an arbitrary angle, and a wafer. And a non-contact type thickness measuring means for measuring the thickness at a plurality of points in the radial direction. The tilt angle adjusting means adjusts the tilt of the holding means based on the measured thickness of the wafer so that the thickness of the wafer becomes uniform, and the grinding means grinds the wafer in an oblique contact state with the wafer. Proceed.

JP 2010-131687 A

  However, in the grinding apparatus described in Patent Literature 1 described above, when the grinding means grinds the wafer while being fed at a preset constant feed speed, the pressure acting on the grinding area where the grinding means grinds the wafer is obtained. If the wafer feed speed is higher than the wafer grinding speed, an excessive pressing force acts on the wafer, and the wafer may be damaged.

  In order to reduce damage to the wafer, it is conceivable to set the feed speed of the grinding unit to a low speed.However, how much the feed speed of the grinding unit is to be slowed tends to be set based on empirical rules, so that it is efficient. However, there is a problem that grinding cannot be performed.

  Therefore, there arises a technical problem to be solved, such as efficient grinding while reducing damage to the wafer, and an object of the present invention is to solve this problem.

The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 has a holding means for rotatably holding a wafer, and a back surface of the wafer which is pressed by the rotating wafer and ground. Grinding means, a fixed support part for fixing and supporting the holding means in the vertical direction, and a plurality of movable support parts which can expand and contract in the vertical direction, and the holding means can be inclined with respect to the grinding means. The movable support portion is disposed on the upstream side in the rotation direction of the holding device with respect to the fixed support portion, and supports the holding device so as to be able to move up and down in the vertical direction. An upstream-side movable support portion, and a downstream-side movable support portion that is disposed on the downstream side in the rotation direction of the holding means with respect to the fixed support portion and supports the holding means so as to be able to move up and down in the vertical direction. Grinding means viewed from a plane Pressing force measuring means for measuring the pressing force acting on the downstream movable support when pressing the wafer in a circular arc shape which is formed in the grinding region is convex on the downstream side of the rotation center as the rotation direction of the wafer And a control unit for changing a feed speed of the grinding unit so that the pressing force falls within the margin range when the pressing force is out of a predetermined margin range. .

According to this configuration, when the pressing force acting on the downstream-side movable support part is out of the preset margin range, by changing the feed speed of the grinding means, the wafer is maintained at a substantially constant pressure without damaging the wafer. Grinding can be performed. Specifically, when the pressing force acting on the downstream movable support portion falls below the lower limit of the margin range, the feed speed of the grinding means is accelerated, and the pressing force acting on the downstream movable support portion falls within the margin range. When the value exceeds the upper limit, the feed rate of the grinding unit is reduced, so that the grinding can be performed while maintaining an appropriate pressure that does not damage the wafer. In addition, when the pressing force falls within the margin range, the feed speed of the grinding unit is maintained, and only when the pressing force is out of the margin range, the feed speed of the grinding unit is changed. be able to.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the pressing force measuring unit is configured such that the grinding unit presses the downstream movable support unit and the downstream movable support unit is configured to move the vertical movable support unit vertically. Provided is a grinding device that calculates the pressing force based on a pressing amount pressed in a direction.

According to this configuration, in addition to the effect of the first aspect of the invention, the pressing force measuring unit is configured to determine whether the grinding unit is pressed based on the amount of pressing of the downstream movable support that is likely to affect the pressure near the center of the wafer. By calculating the pressing force for pressing the wafer, the control means changes the feed speed of the grinding means so that the pressing force falls within the margin range, thereby suppressing the grinding means from being excessively pushed near the center of the wafer. Therefore, the grinding can be performed at a substantially constant pressure without damaging the wafer.

According to a third aspect of the present invention, a holding means for rotatably holding the wafer, a grinding means for pressing the rotating wafer to grind the back surface of the wafer, and the vertically fixed holding means for supporting the holding means A grinding device comprising: a fixed support portion; and a plurality of movable support portions that can expand and contract in the vertical direction, and a tilting device that can tilt the holding device with respect to the grinding device. A portion disposed upstream of the holding unit in the rotation direction with respect to the fixed support unit, and an upstream movable support unit that supports the holding unit so as to be able to move up and down in a vertical direction; and the holding unit with respect to the fixed support unit. arranged downstream in the rotation direction of the means, vertically movable and the downstream movable support for supporting, consists, before Symbol grinding means through the rotation center of rotation of the wafer when viewed from the plane of the holding means in a vertical direction Convex in the downstream direction The pressing force acting on the upstream movable support portion and the pressing force acting on the downstream movable support portion when pressing the wafer in the arc-shaped grinding region are weighted average to obtain the upstream movable support. Pressing force measuring means for calculating a pressing force at an arbitrary virtual support point on a straight line connecting the portion and the downstream movable support portion, and when the pressing force is out of a predetermined margin range, the pressing force reduces the margin. Control means for changing the feed speed of the grinding means so as to fall within the range .

According to this configuration, when the pressing force at an arbitrary virtual support point on a straight line connecting the upstream movable support portion and the downstream movable support portion deviates from a preset margin range, the feed speed of the grinding means is reduced. By making the change, the grinding process can be performed at a substantially constant pressure without damaging the wafer. In addition, when the pressing force falls within the margin range, the feed speed of the grinding unit is maintained, and only when the pressing force is out of the margin range, the feed speed of the grinding unit is changed. be able to.

The invention of claim 4, wherein, in addition to the configuration of the invention according to claim 3, before Symbol pressing force measuring means, the upstream movable support the grinding means pushes the wafer pushed to the vertical direction A grinding device for calculating a pressing force at the virtual support point by performing a weighted average of a pushed amount and a pushing amount of the downstream movable support portion pushed in the vertical direction.

According to this configuration, in addition to the configuration of the third aspect of the invention, the pressing force measuring means calculates the pressing force at the virtual support point by performing a weighted average of the pressing amounts of the upstream movable support portion and the downstream movable support portion. By calculating, the control means changes the feed speed of the grinding means so that the pressing force falls within the margin range, and it is suppressed that the grinding means is excessively pushed into the wafer, thereby damaging the wafer. Grinding can be performed at a constant pressure without any pressure.

According to a fifth aspect of the present invention, a holding means for rotatably holding a wafer, a grinding means pressed by the rotating wafer to grind the back surface of the wafer , and the holding means fixed and supported in a vertical direction. Grinding for grinding the wafer with a grinding device having a fixed support portion and a plurality of movable support portions that can expand and contract in the vertical direction, and a tilting device that can tilt the holding device with respect to the grinding device. The method, wherein the movable support portion is disposed on the upstream side in the rotation direction of the holding means with respect to the fixed support portion, and the upstream movable support portion supports the holding means so as to be able to move up and down in a vertical direction. A downstream movable support portion that is disposed on the downstream side in the rotation direction of the holding unit with respect to the fixed support unit and that supports the holding unit so as to be able to move up and down in the vertical direction. Center of rotation And measuring the pressing force measuring means the pressing force acting on the downstream movable support when pressing the wafer in the grinding region formed in a convex arc shape on the downstream side in the rotation direction Ri, the press A control unit changing a feed speed of the grinding unit so that the pressing force falls within the margin range when the pressure is out of a predetermined margin range.

According to this configuration, when the pressing force acting on the downstream movable support portion that easily affects the pressure near the center of the wafer is out of the preset margin range, by changing the feed speed of the grinding unit, Grinding can be performed at a substantially constant pressure without damaging the wafer. In addition, when the pressing force falls within the margin range, the feed speed of the grinding unit is maintained, and only when the pressing force is out of the margin range, the feed speed of the grinding unit is changed. be able to.

  According to the present invention, when the pressing force acting on the movable support portion deviates from a preset margin range, the feed rate of the grinding means is changed to perform the grinding at a constant pressure without damaging the wafer. be able to. In addition, when the pressing force falls within the margin range, the feed speed of the grinding unit is maintained, and only when the pressing force is out of the margin range, the feed speed of the grinding unit is changed. be able to.

1 is a side view showing a grinding device according to one embodiment of the present invention. The top view of the grinding device shown in FIG. FIG. 3 is a partial cross-sectional view taken along the line II of FIG. 2 showing an internal structure of the tilting unit and a holding unit. 5 is a flowchart showing a grinding method according to one embodiment of the present invention. 9 is a flowchart illustrating a grinding method according to a modification of the present invention.

  The grinding apparatus according to the present invention includes: a holding unit that holds a wafer; and a grinding unit that presses the wafer to grind the wafer in order to achieve an object of performing efficient grinding while reducing damage to the wafer. A fixed support portion that fixes and supports the holding means in the vertical direction, and a plurality of movable support portions that can expand and contract in the vertical direction, and an inclining means that can incline the holding means with respect to the grinding means. And a pressing force measuring means for measuring the pressing force acting on the movable support portion, and the grinding means such that when the pressing force is out of a predetermined margin range, the pressing force is within the margin range. And control means for changing the feed speed.

  A grinding method according to the present invention includes a holding unit that holds a wafer and a grinding unit that presses the wafer to grind the wafer in order to achieve an object of performing efficient grinding while reducing damage to the wafer. A fixed support portion that fixes and supports the holding means in the vertical direction, and a plurality of movable support portions that can expand and contract in the vertical direction, and an inclining means that can incline the holding means with respect to the grinding means. A grinding method for grinding a wafer with a grinding device, wherein the step of measuring the pressing force acting on the movable support portion, and when the pressing force is out of a predetermined margin range, the pressing force is within the margin range. And changing the feed speed of the grinding means.

  Hereinafter, a grinding device 1 according to an embodiment of the present invention will be described with reference to the drawings. In the following examples, when referring to the number, numerical value, amount, range, and the like of the constituent elements, unless otherwise specified and in principle clearly limited to a specific number, the specific number is used. The present invention is not limited to this, and may be more than or less than a specific number. The configuration of the apparatus is not limited to a grinding apparatus, and a polishing apparatus in which a grinding shaft is replaced with a polishing shaft may be used.

  Also, when referring to the shape and positional relationship of components, etc., those that are substantially similar or similar to the shape, etc., unless otherwise specified, and in cases where it is clearly considered in principle not so, etc. Including.

  In addition, the drawings may be exaggerated, for example, by enlarging a characteristic portion in order to make the characteristics easy to understand, and the dimensional ratios and the like of the components are not always the same as the actual ones. In the cross-sectional views, hatching of some components may be omitted in order to make the cross-sectional structure of the components easy to understand.

  FIG. 1 is a side view showing a basic configuration of the grinding device 1. FIG. 2 is a plan view showing the grinding device 1. FIG. 3 is a partial cross-sectional view taken along line II of FIG. 2 showing the internal structure of the tilting means 6 and the holding means 3.

  The grinding device 1 forms a thin film by grinding the back surface of the wafer W by the grinding means 2. The grinding means 2 includes a grindstone 21, a spindle 22 having the grindstone 21 attached to the tip, and a spindle feed mechanism 23 for moving the spindle 22 in the vertical direction V.

  The grindstone 21 is horizontally mounted on the tip of a spindle 22. The wafer W is ground by the whetstone 21 being pressed against the wafer W. As the grindstone 21, for example, a cup-type grindstone of # 6000 may be adopted. Hereinafter, the arc-shaped range in which the grindstone 21 grinds the wafer W is referred to as “grinding area A”.

  The spindle 22 rotates the grindstone 21 along a rotation direction C1 about a rotation axis a1 by a motor (not shown). The rotation speed of the spindle 22 is set to, for example, 2000 prm.

  The spindle feed mechanism 23 includes two linear guides 23a for connecting the column 4 and the spindle 22, and a known ball screw slider mechanism (not shown) for moving the spindle 22 up and down in the vertical direction V.

  Below the grinding means 2, a wafer chuck 3 as a holding means is arranged. The wafer chuck 3 includes a chuck 31 and an air bearing 32. In order to continuously grind a plurality of wafers W, the grinding apparatus 1 includes a plurality of wafer chucks 3. The plurality of wafer chucks 3 are arranged at predetermined intervals on the circumference around the rotation axis of the index table 5.

  An chuck (not shown) made of a porous material such as alumina is embedded in the upper surface of the chuck 31. Inside the chuck 31 and the air bearing 32, a pipe (not shown) extending to the surface of the chuck 31 is arranged. The conduit is connected to a vacuum source (not shown), a compressed air source and a water supply source (not shown) via a rotary joint (not shown) connected to the rotor 32 a of the air bearing 32. When the vacuum source is activated, the wafer W placed on the chuck 31 is suction-held by the chuck 31. Further, when the compressed air source or the water supply source is activated, the suction between the wafer W and the chuck 31 is released.

  The air bearing 32 includes a rotor 32a rotatable around a rotation axis a2, and a stator 32b arranged on the outer periphery of the rotor 32a. The rotor 32a and the chuck 31 are fixed with bolts (not shown). The rotor 32a is connected to a rotary joint, and rotates the chuck 31 about the rotation axis a2 in the rotation direction C2. A predetermined gap (air gap) is provided between the rotor 32a and the stator 32b. By supplying compressed air from the outside to the gap, the rotor 32a rotates without contact with the stator 32b. be able to. The rotation speed of the chuck 31 is set to, for example, 200 rpm.

  The grinding device 1 includes a tilting unit 6 that tilts the rotation axis a2 of the wafer chuck 3 with respect to the rotation axis a1 of the grindstone 21. The inclining means 6 includes a tilt table 61, a fixed support 62, an upstream movable support 63, and a downstream movable support 64. Note that the number of movable supports that can be raised and lowered in the vertical direction V used in the grinding device 1 is not limited to two, and may be three or more.

  The tilt table 61 is formed in a substantially triangular shape in plan view. In the tilt table 61, a fixed support part 62, and an upstream movable support part 63 and a downstream movable support part 64 as movable support parts are arranged 120 degrees apart on the circumference around the rotation axis a2. ing.

  The fixed support portion 62 is fastened to the tilt table 61 by bolts 62a.

  The upstream movable support portion 63 is disposed upstream of the fixed support portion 62 in the rotation direction C2 of the wafer chuck 3. Since the structure of the upstream movable support 63 is the same as that of the downstream movable support 64, the structure of the downstream movable support 64 will be described as an example, and the structure of the upstream movable support 63 will be described. Omitted.

  The downstream movable support portion 64 is disposed downstream of the fixed support portion 62 in the rotation direction C2 of the wafer chuck 3. The downstream movable support portion 64 includes a nut 64a embedded in the tilt table 61, a tilt ball screw 64b fixed to the index table 5, and an upper portion screwed to the nut 64a, and a tilt motor for rotating the tilt ball screw 64b. 64c. The downstream movable support portion 64 is formed longer in the vertical direction V than the fixed support portion 62.

  Since the grinding region A is formed in an arc shape that is convex downward on the paper surface of FIG. 2 in plan view, the distance between the downstream movable support portion 64 and the grinding region A is different from the upstream movable support portion 63 and the grinding region. It is set shorter than the distance to A. That is, the pressing force with which the grindstone 21 presses the wafer W acts more strongly on the downstream movable support portion 64 than on the upstream movable support portion 63.

  The grinding device 1 includes a pressing force measuring unit 7 that measures a pressing force acting on the movable support when the grinding wheel 21 presses the wafer W. The pressing force measuring means 7 includes a first scale 71, a second scale 72, and a pressure converter 73.

  The first scale 71 is disposed in the vicinity of the upstream movable support 63, and measures the amount of pushing of the upstream movable support 63 in the vertical direction V by the pressing force of the grindstone 21. Since the structure of the first scale 71 is the same as that of the second scale 72, the structure of the second scale 72 will be described as an example, and the description of the first scale 71 will be omitted.

  The second scale 72 is arranged near the downstream movable support 63. The second scale 72 is attached to the index table 5, and its upper end projects from the index table 5 and abuts on the tilt table 61. When the tilt table 61 is pushed downward in the vertical direction V, the second scale 72 contracts in the longitudinal direction, and by measuring the amount of contraction, the amount of pushing of the downstream movable support portion 63 is measured. In this way, the second scale 72 measures the amount of pushing of the downstream movable support portion 64 in the vertical direction V by the pressing force of the grindstone 21.

  The pressure converter 73 calculates the pressing force acting on the upstream movable support 63 and the downstream movable support 64 based on the amount of pushing of the upstream movable support 63 and the downstream movable support 64. The specific operation of the pressure converter 73 will be described later. The pressure converter 73 has a data for calculating the pressing force acting on the upstream movable support 63 from the scale value of the first scale 71 and the downstream movable support 64 based on the scale value of the second scale 72. Data for calculating the acting pressing force is stored. In addition to the above-described configuration, the pressing force measuring unit 7 may use a load cell or the like that directly measures the pressure acting on the upstream movable support 63 or the downstream movable support 64.

  The operation of the grinding device 1 is controlled by the control device 8. The control device 8 controls each component of the grinding device 1. The control device 8 includes, for example, a CPU, a memory, and the like. The function of the control device 8 may be realized by controlling using software, or may be realized by operating using hardware.

  The control device 8 tilts the rotation axis a2 with respect to the rotation axis a1 based on the thickness of the wafer W measured by a thickness sensor (not shown) so that a desired wafer thickness is obtained. Adjust the processing range to be ground. In addition, the thickness sensor is not limited to the one included in the configuration of the grinding device 1. For example, the thickness sensor may feed back data measured by an external device of the grinding device 1 to the control device 8. The upstream movable support portion 63 and the downstream movable support portion 64 independently expand and contract along the vertical direction V, and the tilt table 61 is inclined with respect to the fixed support portion 62, so that the rotating shaft a2 becomes the rotating shaft a1. Can be inclined with respect to Hereinafter, the angle of the rotation axis a2 with respect to the rotation axis a1 is referred to as “tilt angle”.

  The control device 8 stores data of the grinding amount of the wafer W according to the tilt angle. Thereby, the thickness of the wafer W before grinding or the thickness of the wafer W during grinding is measured, and the grinding amount and the tilt angle are adjusted from the difference between this thickness and the desired wafer thickness.

  Further, the control device 8 functions as a control unit that controls the ball screw of the ball screw slider mechanism to change the feed speed of the grinding unit 2. The control device 8 stores a margin range of the pressing force acting on the movable support used when determining whether or not to change the feed speed of the grinding means 2. The upper and lower limits, and the upper and lower limits of the pressing force applied to the movable support portion when the grindstone 21 is sent so as not to damage the wafer W during the grinding of the wafer W during the grinding of the wafer W. Between the values. The control of the feed speed of the pressure grinding means 2 will be described later.

  Next, the operation of the grinding device 1 will be described with reference to the drawings. FIG. 4 is a flowchart showing a procedure for grinding the wafer W using the grinding apparatus 1.

  First, after the grinding conditions such as the tilt angle of the tilting means 6 are adjusted, the initial value of the second scale 72, that is, the scale value of the second scale 72 before the grinding wheel 21 contacts the wafer W is acquired (S1). ).

  Next, the grindstone 21 is pressed against the wafer W to start the grinding (S2). The initial feed speed at which the spindle feed mechanism 23 feeds the grindstone 21 is set to, for example, 0.7 μm / s. As shown in FIG. 2, an area A where the grinding wheel 21 grinds the wafer W is formed in an arc shape passing through the center of the wafer W.

  Next, the pushing amount of the downstream movable support 64 is measured (S3). The pushing amount of the downstream movable support portion 64 corresponds to the difference between the initial value of the second scale 72 obtained in step S1 and the scale value of the second scale 72 after the start of the grinding.

  Next, the pressure converter 73 calculates the pressing force acting on the downstream movable support 64 based on the amount of pushing of the downstream movable support 64 (S4). Specifically, the pressure conversion unit 73 calls the value of the pressing force acting on the downstream movable support 64 that is substantially proportional to the pushing amount of the downstream movable support 64 calculated in step S3.

  Next, the control device 8 determines whether the pressing force acting on the downstream movable support portion 64 calculated in step S4 is out of the preset pressure margin range (S5). For the margin range, for example, the upper limit is set to a pressing force corresponding to the maximum allowable pressing amount of the downstream movable support portion 64 of 0.25 μm, and the lower limit is set to the maximum allowable pressing amount of the downstream movable support portion 64 of 0.15 μm. It is conceivable to set a corresponding pressing force.

  If the pressing force calculated in step S4 falls within the margin range, the control device 8 maintains the feed speed of the grinding means 2 (S6).

  If the pressing force calculated in step S4 exceeds the upper limit value of the margin range, that is, if the grindstone 21 and the wafer W come into contact with each other in an overpressure state, the control device 8 controls the ball screw slider mechanism to perform grinding. The feed speed of the means 2 is reduced (S7). The feed speed of the grinding means 2 is reduced by a predetermined value set in advance, for example, 0.1 μm / s. The minimum feed speed of the grinding means 2 is set to 0.03 μm / s.

  When the pressing force calculated in step S4 is lower than the lower limit value of the margin range, that is, when the grindstone 21 and the wafer W come into contact with each other in a reduced pressure state, the control device 8 controls the ball screw slider mechanism to The feed speed of the grinding means 2 is increased (S8). The feed speed of the grinding means 2 is accelerated by a predetermined value, for example, 0.1 μm / s.

  After controlling the feed speed of the grinding means 2, the control device 8 determines whether or not the grinding has been completed (S9). When the wafer W has been ground to a desired final thickness, the control device 8 determines that the grinding has been completed. The final thickness of the wafer W having an initial thickness of 270 μm is set to, for example, 250 μm.

  If the thickness of the wafer W has not reached the final thickness, the control device 8 determines that the grinding has not been completed (No in step S9), and returns to step S3.

  If the thickness of the wafer W has reached the final thickness, the control device 8 determines that the grinding has been completed (Yes in step S9), and ends the grinding.

  Accordingly, the pressing force measuring means 7 determines the pressing force with which the grindstone 21 presses the wafer W based on the pressing amount of the downstream movable support portion 64 which is close to the grinding area A and easily affects the pressure near the center of the wafer W. The calculation suppresses the grindstone 21 from being excessively pushed into the vicinity of the center of the wafer W, so that damage to the wafer W can be reduced.

  Next, a modified example of the grinding method using the grinding device 1 will be described with reference to the drawings. FIG. 5 is a flowchart illustrating a modified example of the grinding method using the above-described grinding device 1. In the description of the present modification, duplicate descriptions of the above-described embodiments will be omitted.

  The initial values of the first scale 71 and the second scale 72 are obtained (S10). The initial value of the first scale 71 is a scale value of the first scale 71 before the grinding stone 21 contacts the wafer W.

  Next, the grinding wheel 21 is pressed against the wafer W to start the grinding (S11). As shown in FIG. 2, an area A where the grinding wheel 21 grinds the wafer W is formed in a circular arc shape passing through the center of the wafer W and projecting downward on the paper of FIG.

  Next, the pushing amounts of the upstream movable support 63 and the downstream movable support 64 are measured (S12). The pushing amount of the upstream movable support 63 corresponds to the difference between the initial value of the first scale 71 obtained in step S10 and the scale value of the first scale 71 after the start of the grinding.

  The pressure converter 73 calculates the pressing force acting on the movable support by weighing the pushing amount of the upstream movable support 63 and the push of the downstream movable support 64 measured in step S12 (S13). . Specifically, assuming a virtual push amount of the virtual support point P at an arbitrary position on the line segment L in FIG. 2, the push amount of the upstream movable support portion 63 and the push amount of the downstream movable support portion 64 are determined. The weighted average is used to calculate the virtual pushing amount at which the virtual support point P is pushed into the grindstone 21, and the pressure acting on the virtual supporting point P that is substantially proportional to the virtual pushing amount is called.

  Next, the control device 8 determines whether or not the pressing force acting on the virtual support point P calculated in step S13 is out of a preset pressure margin range (S14).

  If the pressing force acting on the virtual support point P calculated in step S13 falls within the margin range, the control device 8 controls the ball screw slider mechanism to maintain the feed speed of the grinding means 2 (S15). .

  If the pressing force acting on the virtual support point P calculated in step S13 exceeds the upper limit value of the margin range, that is, if the grinding wheel 21 and the wafer W abut in an overpressure state, the control device 8 controls the ball screw slider. The mechanism is controlled to reduce the feed speed of the grinding means 2 (S16).

  When the pressing force acting on the virtual support point P calculated in step S13 is lower than the lower limit value of the margin range, that is, when the grindstone 21 and the wafer W are brought into contact with each other in a reduced pressure state, the control device 8 performs the grinding. The feed speed of the means 2 is increased (S17).

  After controlling the feed speed of the grinding means 2, the control device 8 determines whether or not the grinding has been completed (S18). When the wafer W has been ground to a desired final thickness, the control device 8 determines that the grinding has been completed.

  If the thickness of the wafer W has not reached the final thickness, the control device 8 determines that the grinding has not been completed (No in step S18), and returns to step S12.

  When the thickness of the wafer W has reached the final thickness, the control device 8 determines that the grinding has been completed (Yes in step S18), and ends the grinding.

  Accordingly, the pressing force measuring means 7 calculates the weighted average of the amounts of pushing in the two points of the upstream movable support part 63 and the downstream movable support part 64 which are arranged so as to sandwich the grinding area A, and By calculating the pressing force for pressing, the grinding process can be performed at a substantially constant pressure without damaging the wafer W.

  In addition, by appropriately adjusting the position of the virtual support point P according to the shape of the wafer W after the grinding, the contact state between the grindstone 21 and the wafer W is adjusted so that the wafer W is ground into a desired shape. be able to.

  In this way, the above-described grinding apparatus 1 damages the wafer W by changing the feed speed of the grinding means 2 when the pressing force acting on the movable support part is out of the preset margin range. Grinding can be performed at a substantially constant pressure without giving. In addition, when the pressing force is within the margin range, the feed speed of the grinding means 2 is maintained, and only when the pressing force is out of the margin range, the feed speed of the grinding means 2 is changed. Grinding can be performed.

  The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

DESCRIPTION OF SYMBOLS 1 ... Grinding apparatus 2 ... Grinding means 21 ... Grinding stone 22 ... Spindle 23 ... Spindle feed mechanism 23a ... Linear guide 3 ... Wafer chuck (holding means)
31 ... Chuck 32 ... Air bearing 32a ... Rotor 32b ... Stator 4 ... Column 5 ... Index table 6 ... Inclination means 61 ... Tilt table 62 ... Fixed support Part 62a Bolt 63 Upstream movable support (movable support)
64 ··· Downstream movable support (movable support)
64a ··· Nut 64b ··· Tilt ball screw 64c ··· Tilt motor 7 ··· Pressing force measuring means 71 ··· First scale 72 ··· Second scale 73 ··· Pressure converter 8: Control device A: Grinding area W: Wafer

Claims (5)

Holding means for rotatably holding the wafer, and the grinding means is pressed against the wafer to rotating grinding the back surface of the wafer, in the vertical direction and the fixing support part for supporting and fixing the holding means in a vertical direction A grinding device comprising: a plurality of telescopic movable support portions; and an inclining means capable of inclining the holding means with respect to the grinding means,
The movable support section,
An upstream movable support portion that is disposed on the upstream side in the rotation direction of the holding unit with respect to the fixed support portion and supports the holding unit so as to be able to move up and down in a vertical direction.
A downstream movable support portion that is disposed on the downstream side in the rotation direction of the holding unit with respect to the fixed support portion and supports the holding unit so as to be able to move up and down in a vertical direction;
Consisting of
When the grinding unit presses the wafer in a grinding area formed in a circular arc shape convex on the downstream side in the rotation direction passing through the center of rotation of the wafer as viewed from a plane , a push acting on the downstream movable support portion is provided. Pressing force measuring means for measuring pressure,
When the pressing force is out of a predetermined margin range, control means for changing the feed rate of the grinding means so that the pressing force is within the margin range,
A grinding device comprising: The pressing force measuring means, wherein the grinding means presses the downstream movable support portion, and the downstream movable support portion calculates the pressing force based on the amount of pushing in the vertical direction. The grinding device according to claim 1, wherein Holding means for rotatably holding the wafer, grinding means pressed by the rotating wafer to grind the back surface of the wafer, a fixed support portion for fixing and supporting the holding means in the vertical direction, and in the vertical direction A grinding device comprising: a plurality of telescopic movable support portions; and a tilting means capable of tilting the holding means with respect to the grinding means,
The movable support section,
An upstream movable support portion that is disposed on the upstream side in the rotation direction of the holding unit with respect to the fixed support portion and supports the holding unit so as to be able to move up and down in the vertical direction.
A downstream movable support portion that is arranged on the downstream side in the rotation direction of the holding unit with respect to the fixed support portion and supports the holding unit so as to be able to move up and down in a vertical direction;
Consisting of
Acting on the upstream movable support in front Symbol grinding means pushes the wafer in a circular arc shape which is formed in the grinding region is convex on the downstream side of the rotation center as the rotation direction of the wafer when viewed from the plane The pressing force and the pressing force acting on the downstream movable support portion are weighted average to calculate the pressing force at an arbitrary virtual support point on a straight line connecting the upstream movable support portion and the downstream movable support portion. Pressing force measuring means,
When the pressing force is out of a predetermined margin range, control means for changing the feed rate of the grinding means so that the pressing force is within the margin range,
Grinding apparatus characterized by comprising a. Before SL pressing force measuring means, push amount of the grinding means pushes amount the upstream movable support is pushed in the vertical direction by pressing the wafer and the downstream-side movable support is pushed in the vertical direction The grinding device according to claim 3 , wherein the pressing force at the virtual support point is calculated by performing a weighted average of the following. Holding means for rotatably holding the wafer, and the grinding means is pressed against the wafer to rotating grinding the back surface of the wafer, in the vertical direction and the fixing support part for supporting and fixing the holding means in a vertical direction A grinding method, comprising: a plurality of telescopic movable support portions; and a tilting device having a tilting device capable of tilting the holding device with respect to the grinding device;
The movable support section,
An upstream movable support portion that is disposed on the upstream side in the rotation direction of the holding unit with respect to the fixed support portion and supports the holding unit so as to be able to move up and down in a vertical direction.
A downstream movable support portion that is disposed on the downstream side in the rotation direction of the holding unit with respect to the fixed support portion and supports the holding unit so as to be able to move up and down in a vertical direction;
Consisting of
When the grinding unit presses the wafer in a grinding area formed in a circular arc shape protruding downstream in the rotation direction passing through the center of rotation of the wafer when viewed from a plane , a push acting on the downstream movable support portion is provided. Measuring the pressure with a pressing force measuring means ,
When the pressing force is out of a predetermined margin range, a step in which the control means changes the feed speed of the grinding means so that the pressing force is within the margin range,
A grinding method comprising: