JP2017127958A - Grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device which efficiently performs grinding work while reducing damage to a wafer, and to provide a grinding method.SOLUTION: A grinding device 1 includes: a grind stone 21 which is pressed by a wafer W to grind the wafer W; a wafer chuck 3 which holds the wafer W; inclination means which may incline the wafer chuck 3 relative to the grind stone 21; pressing force measurement means 7 which measures a pressing force acting on a downstream side movable support part 64; and a control device which changes a feeding speed of the grind stone 21 so that the pressing force is in a predetermined margin range when the pressing force deviates from the predetermined margin range.SELECTED DRAWING: Figure 2

Description

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

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

  As a grinding apparatus for performing backside grinding of a wafer, Patent Document 1 discloses a holding unit that holds a wafer, a grinding unit that grinds the wafer, an inclination angle adjusting unit that adjusts an inclination of the holding unit to an arbitrary angle, and a wafer. And a non-contact type thickness measuring means for measuring the thickness of the material 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 wafer thickness so that the thickness of the wafer is uniform, and the grinding means performs grinding in a state of being in contact with the wafer obliquely. Proceed.

JP 2010-131687 A

  However, in the grinding apparatus described in Patent Document 1 as described above, the grinding means grinds the wafer while being fed at a preset constant feed rate, and the pressure acting on the grinding region where the grinding means grinds the wafer. Therefore, when the wafer feed speed is higher than the wafer grinding speed, an excessive pressing force may act on the wafer and damage the wafer.

  In order to reduce damage to the wafer, it is conceivable to set the feed speed of the grinding means to a low speed, but how much the feed speed of the grinding means is delayed tends to be set based on empirical rules and is efficient. However, there was a problem that grinding could not be performed.

  Therefore, a technical problem to be solved arises that grinding is efficiently performed while reducing damage to the wafer, and the present invention aims to solve this problem.

  The present invention has been proposed to achieve the above object, and the invention according to claim 1 is characterized in that the holding means for holding the wafer, the grinding means for pressing the wafer to grind the wafer, and the holding A fixed support portion that fixes and supports the means in the vertical direction, and a plurality of movable support portions that can extend and contract in the vertical direction, and an inclination means that can tilt 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, and the pressing force is within the margin range when the pressing force is out of a predetermined margin range. And a control means for changing the feed rate of the grinding means.

  According to this configuration, when the pressing force acting on the movable support part is out of a preset margin range, the grinding process is performed at a substantially constant pressure without damaging the wafer by changing the feed speed of the grinding means. Can be implemented. Specifically, when the pressing force acting on the movable support portion falls below the lower limit value of the margin range, the feed speed of the grinding means is accelerated, and the pressing force acting on the movable support portion exceeds the upper limit value of the margin range. In this case, by reducing the feed speed of the grinding means, it is possible to perform grinding while maintaining an appropriate pressure that does not damage the wafer. In addition, when the pressing force is within the margin range, the grinding device feed rate is maintained, and when the pressing force is out of the margin range, the grinding device feed rate is changed, so grinding is performed efficiently. be able to.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the pressing force measuring means is configured such that the grinding means presses the movable support portion and the movable support portion is pushed in the vertical direction. A grinding device that calculates the pressing force based on the amount of pressing is provided.

  According to this configuration, in addition to the effect of the first aspect of the invention, the pressing force measuring means is configured such that the grinding means presses the wafer based on the amount of pressing the movable support portion is pressed when the grinding means presses the wafer. By calculating the pressing force, the control means changes the feed speed of the grinding means so that the pressing force is within the margin range, and the grinding means is prevented from being excessively pushed into the wafer. Grinding can be performed at a substantially constant pressure without causing damage.

  According to a third aspect of the invention, in addition to the configuration of the second aspect of the invention, the movable support portion is disposed upstream of the fixed support portion in the rotation direction of the holding means, and the holding means is arranged vertically. An upstream movable support portion that is supported so as to be able to move up and down in a direction, and a downstream movable support portion that is disposed downstream of the fixed support portion in the rotation direction of the holding means and supports the holding means so as to be able to move up and down in the vertical direction. The pressing force measuring means comprises a grinding device that calculates a pressing force based on an amount of pushing the downstream movable support portion pushed in the vertical direction when the grinding means presses the wafer. provide.

  According to this configuration, in addition to the effect of the invention according to claim 2, the pressing force measuring means is configured so that the grinding means removes the wafer based on the pushing amount of the downstream movable support portion that easily affects the pressure near the center of the wafer. By calculating the pressing force to be pressed, the control unit changes the feed speed of the grinding unit so that the pressing force is within the margin range, and the grinding unit is prevented from being excessively pushed near the center of the wafer. Therefore, grinding can be performed at a substantially constant pressure without damaging the wafer.

  According to a fourth aspect of the invention, in addition to the configuration of the second aspect of the invention, the movable support portion is disposed upstream of the fixed support portion in the rotation direction of the holding means, and the holding means is arranged vertically. An upstream movable support portion that is supported so as to be able to move up and down in a direction, and a downstream movable support portion that is disposed downstream of the fixed support portion in the rotation direction of the holding means and supports the holding means so as to be able to move up and down in the vertical direction. The pressing force measuring means comprises: an amount by which the upstream movable support portion is pushed in the vertical direction when the grinding means presses the wafer; and a downstream movable support portion in the vertical direction. Provided is a grinding device that calculates a pressing force by averaging the amount of pressing that has been pressed.

  According to this configuration, in addition to the configuration of the invention described in claim 2, the pressing force measuring means weights and averages the pushing amounts of the upstream movable support portion and the downstream movable support portion, and the grinding means presses the wafer. By calculating the pressing force, the control unit changes the feed speed of the grinding unit so that the pressing force is within the margin range, and the grinding unit is prevented from being pushed excessively into the wafer, thereby causing damage to the wafer. Grinding can be performed at a constant pressure without imparting.

  According to a fifth aspect of the present invention, there is provided a holding means for holding a wafer, a grinding means for pressing the wafer to grind the wafer, a fixed support portion for fixing and supporting the holding means in the vertical direction, and the vertical direction. A grinding method for grinding the wafer with a grinding apparatus comprising: a plurality of movable support portions that can be extended and contracted; and a tilting unit capable of tilting the holding unit with respect to the grinding unit. Measuring the pressing force acting on the support, and changing the feed speed of the grinding means so that the pressing force falls within the margin range when the pressing force is outside a predetermined margin range; A grinding method is provided.

  According to this configuration, when the pressing force acting on the movable support part is out of a preset margin range, the grinding process is performed at a substantially constant pressure without damaging the wafer by changing the feed speed of the grinding means. Can be implemented. In addition, when the pressing force is within the margin range, the grinding device feed rate is maintained, and when the pressing force is out of the margin range, the grinding device feed rate is changed, so grinding is performed efficiently. be able to.

  The present invention performs grinding at a constant pressure without damaging the wafer by changing the feed speed of the grinding means when the pressing force acting on the movable support part is out of a preset margin range. be able to. In addition, when the pressing force is within the margin range, the grinding device feed rate is maintained, and when the pressing force is out of the margin range, the grinding device feed rate is changed, so grinding is performed efficiently. be able to.

The side view which shows the grinding device which concerns on one Example of this invention. The top view of the grinding apparatus shown in FIG. FIG. 3 is a partial cross-sectional view taken along the line I-I of FIG. The flowchart which shows the grinding method which concerns on one Example of this invention. The flowchart which shows the grinding method which concerns on the modification of this invention.

  A grinding apparatus according to the present invention includes a holding unit that holds a wafer and a grinding unit that is pressed against the wafer and grinds the wafer in order to achieve the object of performing grinding efficiently while reducing damage to the wafer. And a fixed support part that fixes and supports the holding means in the vertical direction and a plurality of movable support parts that can be expanded and contracted in the vertical direction, and an inclination means that can tilt the holding means with respect to the grinding means. A grinding force measuring device for measuring a pressing force acting on the movable support portion, and a grinding device so that the pressing force is within the margin range when the pressing force is out of a predetermined margin range. This is realized by including control means for changing the feed rate.

  The grinding method according to the present invention includes a holding unit that holds a wafer and a grinding unit that is pressed against the wafer and grinds the wafer in order to achieve the object of performing grinding efficiently while reducing damage to the wafer. And a fixed support part that fixes and supports the holding means in the vertical direction and a plurality of movable support parts that can be expanded and contracted in the vertical direction, and an inclination means that can tilt the holding means with respect to the grinding means. A method of measuring a pressing force acting on the movable support unit, and when the pressing force is out of a predetermined margin range, the pressing force is within the margin range. And a step of changing the feed rate of the grinding means.

  Hereinafter, a grinding apparatus 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, quantity, range, etc. of the constituent elements, the specific number is used unless otherwise specified and clearly limited to a specific number in principle. It is not limited, and may be a specific number or more, and the apparatus configuration is not limited to a grinding apparatus, and a polishing apparatus in which a grinding axis is replaced with a polishing axis may be used.

  In addition, when referring to the shapes and positional relationships of components, etc., those that are substantially similar to or similar to the shapes, etc., unless otherwise specified or otherwise considered in principle to be apparent. Including.

  In addition, the drawings may be exaggerated by enlarging characteristic portions in order to make the features easy to understand, and the dimensional ratios and the like of the constituent elements are not always the same. In the cross-sectional view, hatching of some components may be omitted in order to facilitate understanding of the cross-sectional structure of the components.

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

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

  The grindstone 21 is attached horizontally to the tip of the spindle 22. When the grindstone 21 is pressed against the wafer W, the wafer W is ground. For the grindstone 21, for example, a cup-type grindstone of # 6000 can be used. Hereinafter, an arc-shaped range in which the grindstone 21 grinds the wafer W is referred to as “grinding region A”.

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

  The spindle feed mechanism 23 includes two linear guides 23 a that connect the column 4 and the spindle 22, and a known ball screw slider mechanism (not shown) that raises and lowers the spindle 22 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.

  The chuck 31 has an adsorbent (not shown) made of a porous material such as alumina embedded in the upper surface. In the chuck 31 and the air bearing 32, a pipe line (not shown) extending to the surface of the chuck 31 is disposed. The pipe line is connected to a vacuum source, a compressed air source, and a water supply source (not shown) via a rotary joint (not shown) connected to the rotor 32a of the air bearing 32. When the vacuum source is activated, the wafer W placed on the chuck 31 is sucked and held on the chuck 31. Further, when the compressed air source or the water supply source is activated, the adsorption between the wafer W and the chuck 31 is released.

  The air bearing 32 includes a rotor 32a that can rotate about the rotation axis a2, and a stator 32b that is disposed 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 the rotary joint, and rotates the chuck 31 along the rotation direction C2 around the rotation axis a2. A predetermined gap (air gap) is provided between the rotor 32a and the stator 32b, and the rotor 32a rotates without contact with the stator 32b by supplying compressed air to the gap from the outside. be able to. The number of rotations of the chuck 31 is set to 200 rpm, for example.

  The grinding apparatus 1 is provided with a tilting means 6 for tilting the rotation axis a2 of the wafer chuck 3 with respect to the rotation axis a1 of the grindstone 21. The tilting means 6 includes a tilt table 61, a fixed support portion 62, an upstream side movable support portion 63, and a downstream side movable support portion 64. Note that the number of movable support portions that can be raised and lowered in the vertical direction V used in the grinding apparatus 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 portion 62, an upstream side movable support portion 63 and a downstream side movable support portion 64 as movable support portions are arranged 120 degrees apart from each other around the rotation axis a2. ing.

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

  The upstream movable support portion 63 is disposed on the upstream side in the rotation direction C <b> 2 of the wafer chuck 3 with respect to the fixed support portion 62. Since the structure of the upstream movable support portion 63 is the same as that of the downstream movable support portion 64, the structure will be described by taking the downstream movable support portion 64 as an example, and the structure of the upstream movable support portion 63 will be described. Omitted.

  The downstream side movable support portion 64 is disposed on the downstream side in the rotation direction C <b> 2 of the wafer chuck 3 with respect to the fixed support portion 62. The downstream movable support portion 64 includes a nut 64a embedded in the tilt table 61, a tilt ball screw 64b that is fixed to the index table 5 and screwed into the nut 64a at an upper portion, and a tilt motor that rotates 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 area A is formed in a convex arc shape on the lower side in FIG. 2 in plan view, the distance between the downstream movable support section 64 and the grinding area A is equal to the upstream movable support section 63 and the grinding area. It is set to be shorter than the distance from A. That is, the pressing force with which the grindstone 21 presses the wafer W acts more strongly on the downstream side movable support part 64 than on the upstream side movable support part 63.

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

  The first scale 71 is disposed in the vicinity of the upstream side movable support part 63 and measures the amount of pushing that the upstream side movable support part 63 is pushed 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 regarding the first scale 71 will be omitted.

  The second scale 72 is disposed in the vicinity of the downstream side movable support portion 63. The second scale 72 is attached to the index table 5, and the upper end of the second scale 72 protrudes from the index table 5 and is in contact with the tilt table 61. When the tilt table 61 is pushed downward in the vertical direction V, the second scale 72 is shrunk in the longitudinal direction, and the push amount of the downstream movable support 63 is measured by measuring the shrinkage amount. In this way, the second scale 72 measures the amount by which the downstream movable support portion 64 is pushed in the vertical direction V by the pressing force of the grindstone 21.

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

  The operation of the grinding device 1 is controlled by the control device 8. The control device 8 controls each component constituting the grinding device 1. The control device 8 is configured by, for example, a CPU, a memory, and the like. Note that 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 so that a desired wafer thickness can be obtained based on the thickness of the wafer W measured by a thickness sensor (not shown), and the grindstone 21 causes the wafer W to move the wafer W. Adjust the processing range to grind. The thickness sensor is not limited to that included in the configuration of the grinding apparatus 1, and may be one that feeds back data measured by an external device of the grinding apparatus 1 to the control device 8, for example. The upstream side movable support part 63 and the downstream side movable support part 64 independently expand and contract along the vertical direction V, and the tilt table 61 tilts with respect to the fixed support part 62, so that the rotation axis a2 becomes the rotation axis 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 a “tilt angle”.

  The control device 8 stores data on 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.

  The control device 8 also 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 portion used when determining whether or not to change the feed speed of the grinding means 2. This margin range is the upper limit value, the lower limit value, the upper limit value, and the lower limit value of the pressing force acting on the movable support portion when the grindstone 21 is sent so as not to damage the wafer W during grinding of the wafer W. Between the values. Control of the feed rate of the pressure grinding means 2 will be described later.

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

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

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

  Next, the pushing amount of the downstream side movable support part 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 acquired in step S1 and the scale value of the second scale 72 after the start of grinding.

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

  Next, the control device 8 determines whether or not the pressing force acting on the downstream side movable support portion 64 calculated in step S4 is out of a preset pressure margin range (S5). For the margin range, for example, the upper limit value is set to a pressing force corresponding to the maximum allowable push amount 0.25 μm of the downstream movable support portion 64, and the lower limit value is set to the maximum allowable push amount 0.15 μm of the downstream movable support portion 64. It is conceivable to set the corresponding pressing force.

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

  When the pressing force calculated in step S4 exceeds the upper limit value of the margin range, that is, when 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 decelerated (S7). The feed speed of the grinding means 2 is decelerated 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, The feed speed of the grinding means 2 is accelerated (S8). The feed speed of the grinding means 2 is accelerated by a preset predetermined value, for example, 0.1 μm / s.

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

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

  When the thickness of the wafer W has reached the final thickness, the control device 8 determines that the grinding process is finished (Yes in step S9), and finishes the grinding process.

  As a result, the pressing force measuring means 7 generates a pressing force by which the grindstone 21 presses the wafer W based on the pressing amount of the downstream side movable support portion 64 that is close to the grinding region A and easily affects the pressure near the center of the wafer W. By calculating, since the grindstone 21 is suppressed from being excessively pushed near the center of the wafer W, damage to the wafer W can be reduced.

  Next, a modification of the grinding method using the grinding apparatus 1 will be described based on the drawings. FIG. 5 is a flowchart showing a modification of the grinding method using the grinding apparatus 1 described above. Note that, in the description of the present modification, the description that overlaps with the above-described embodiment is omitted.

  The initial values of the first scale 71 and the second scale 72 are acquired (S10). The initial value of the first scale 71 is the scale value of the first scale 71 before the grindstone 21 contacts the wafer W.

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

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

  The pressure conversion unit 73 calculates a pressing force acting on the movable support unit by performing a weighted average of the pushing amount of the upstream movable support unit 63 and the pushing amount of the downstream movable support unit 64 measured in step S12 (S13). . Specifically, assuming the 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 calculated. A virtual push-in amount in which the virtual support point P is pushed into the grindstone 21 is calculated by weighted averaging, and a pressure acting on the virtual support point P substantially proportional to the virtual push-in 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 is 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). .

  When 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, when the grindstone 21 and the wafer W come into contact with each other in an overpressure state, the control device 8 displays 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 in contact with each other in a reduced pressure state, the control device 8 performs the grinding. The feed speed of the means 2 is accelerated (S17).

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

  If the thickness of the wafer W has not reached the final thickness, the control device 8 determines that the grinding process 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 process has ended (Yes in step S18), and ends the grinding process.

  As a result, the pressing force measuring means 7 weights and averages the pushing amounts of the upstream movable support portion 63 and the downstream movable support portion 64 arranged so as to sandwich the grinding area A, and the grindstone 21 is moved to the wafer W. By calculating the pressing force for pressing, the grinding process can be executed 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 grinding, the contact state between the grindstone 21 and the wafer W is adjusted so as to grind the wafer W 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 outside the preset margin range. Grinding can be performed at a substantially constant pressure without giving. Further, since the feed speed of the grinding means 2 is maintained when the pressing force is within the margin range, and the feed speed of the grinding means 2 is changed only when the pressing force is out of the margin range, it is efficient. Grinding can be performed.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

DESCRIPTION OF SYMBOLS 1 ... Grinding device 2 ... Grinding means 21 ... Grinding wheel 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 part (movable support part)
64: Downstream movable support section (movable support section)
64a, nut 64b, ball screw for tilt 64c, motor for tilt 7, pressing force measuring means 71, first scale 72, second scale 73, pressure converter 8 ... Control device A ... Grinding area W ... Wafer

Claims (5)

A holding means for holding the wafer; a grinding means for pressing the wafer to grind the wafer; a fixed support portion for fixing and supporting the holding means in the vertical direction; and a plurality of movable supports that are extendable in the vertical direction. And a tilting means capable of tilting the holding means with respect to the grinding means,
A pressing force measuring means for measuring a pressing force acting on the movable support portion;
Control means for changing the feed speed of the grinding means so that the pressing force falls within the margin range when the pressing force is outside a predetermined margin range;
A grinding apparatus comprising:   The said pressing force measuring means calculates the said pressing force based on the pressing amount by which the said grinding means pressed the said movable support part and the said movable support part was pushed in the said perpendicular direction. The grinding apparatus as described. The movable support portion is
An upstream movable support portion that is disposed upstream of the fixed support portion in the rotation direction of the holding means and supports the holding means so as to be vertically movable;
A downstream movable support portion that is disposed downstream of the fixed support portion in the rotation direction of the holding means and supports the holding means so as to be vertically movable;
Consisting of
3. The pressing force measuring unit calculates a pressing force based on a pressing amount by which the downstream movable support unit is pressed in the vertical direction when the grinding unit presses the wafer. The grinding apparatus as described. The movable support portion is
An upstream movable support portion that is disposed upstream of the fixed support portion in the rotation direction of the holding means and supports the holding means so as to be vertically movable;
A downstream movable support portion that is disposed downstream of the fixed support portion in the rotation direction of the holding means and supports the holding means so as to be vertically movable;
Consisting of
The pressing force measuring means includes an amount of pushing in which the upstream movable support portion is pushed in the vertical direction and a pushing amount in which the downstream movable support portion is pushed in the vertical direction when the grinding means presses the wafer. The grinding apparatus according to claim 2, wherein the pressing force is calculated by averaging the load. A holding means for holding the wafer; a grinding means for pressing the wafer to grind the wafer; a fixed support portion for fixing and supporting the holding means in the vertical direction; and a plurality of movable supports that are extendable in the vertical direction. And a grinding method for grinding the wafer with a grinding device comprising a tilting means capable of tilting the holding means with respect to the grinding means,
Measuring a pressing force acting on the movable support part;
A step of changing the feed rate of the grinding means so that the pressing force falls within the margin range when the pressing force is outside a predetermined margin range;
A grinding method comprising: