JP6099960B2 - Wafer chamfering method and wafer chamfering apparatus - Google Patents

Description

  The present invention relates to a wafer chamfering method and a wafer chamfering apparatus for processing a peripheral end portion of a wafer as a material for a semiconductor element.

  Disc-like thin plate materials used as substrates for integrated circuits such as various crystal wafers and other semiconductor device wafers, and other disc-like thin plate materials made of hard materials including metal materials, such as silicon (Si) single crystal, gallium arsenide (GaAs), A material made of quartz, quartz, sapphire, ferrite, silicon carbide (SiC), etc. (these are collectively referred to simply as a wafer) was thinly cut from a single crystal ingot by a slicing machine and cut from one ingot. A large number of wafers are stored together in one lot.

These wafers are placed on a rotary table of a chamfering processing apparatus and rotated, and the edge (peripheral edge portion) is ground with a grindstone to be chamfered to a predetermined shape and a predetermined surface roughness (Patent Document) 1, 2, 3).
The wafer 1 to be chamfered includes a wafer 1 provided with a V-shaped or U-shaped notch 1n for indicating a reference position in the circumferential direction and a wafer 1 formed with an orientation flat. Chamfered.

As shown in FIG. 13, the edge (peripheral edge) 1a of the wafer 1 has an upper slope 1au inclined by an angle α1 (about 22 °) with respect to the upper plane and an angle α1 (about 22 ° with respect to the lower plane). ) And a lower slope 1ad inclined to each other, and an arc 1c having a radius R1 that smoothly connects between them may be processed into a cross-sectional shape (generally a substantially triangular shape).
In this case, the horizontal length of the upper slope 1au is referred to as “chamfer width X1”, and the horizontal length of the lower slope 1ad is referred to as “chamfer width X2”.

Further, as shown in FIG. 14, the edge 1a of the wafer 1 has an upper slope 1au inclined by an angle α2 with respect to the upper plane, a lower slope 1ad inclined by an angle α2 with respect to the lower plane, and an end face of the edge 1a. A circular peripheral surface 1b that forms a straight line, and two circular arcs having the same radius R2 that smoothly connect between the upper inclined surface 1au and the peripheral end surface 1b and between the lower inclined surface 1ad and the peripheral end surface 1b, It may be processed into a cross-sectional shape (substantially trapezoidal shape) consisting of 1c.
Also in this case, the horizontal length of the upper slope 1au is referred to as “chamfer width X1”, the horizontal length of the lower slope 1ad is referred to as “chamfer width X2”, and the length of the face width of the peripheral edge 1b is referred to as “chamfer width X3”. .

  The wafer chamfering apparatus has a plurality of rotary tables and a plurality of types of grindstones and measuring devices. The wafer is placed on each rotating table, and each grindstone or measuring device receives the wafers on each rotating table. Some wafers can be chamfered simultaneously in parallel by processing, measuring, and sequentially moving between rotary tables (Patent Document 4).

JP-A-1-51912 JP-A-6-104228 JP 2008-177348 A JP 2011-235406 A

However, the shape of the wafer before chamfering, which is thinly cut by the slicing machine from the ingot state, varies from lot to lot depending on the characteristics of the original ingot and slicing machine.
Therefore, in the chamfering process of the wafer, first, the thickness of the wafer and the height of the wafer on the rotary table are measured before the process, and the relative position between the wafer to be processed and the grindstone is adjusted. Thereafter, the wafer at the start end of the lot is chamfered so as to have a predetermined target diameter and target peripheral end shape by a grindstone whose processing position is adjusted. In a chamfering apparatus having a plurality of rotary tables, the wafer is chamfered to a target size and shape by being shared by the respective rotary tables.
Next, the dimensions and shape of the processed wafer are measured with a measuring device, and the second and subsequent wafers are processed into precise target dimensions and shapes from the difference between the measurement results and the target dimensions. The processing position was corrected, and processing of the second and subsequent wafers was started.

However, a wafer cut out by a wire saw of a slicing machine, in particular, as shown in FIG. 16, the wire saw cut formed on the wafer surface depending on the orientation of the wire by the crystal orientation alignment, the state of the wire, and the state of the slicing machine. The heights and pitches of streaks (hereinafter referred to as wire marks M), pitches, warpage of wafers, and the like have a habit of each lot. Further, due to the difference in the position of the wire mark M for each wafer, there is a difference in the thickness of the peripheral edge for each wafer.
Therefore, even if the thickness of the wafer or the height of the wafer on the rotary table is measured, the non-contact type measuring device cannot accurately measure the crest of the wire mark M, and the average thickness in the vicinity is measured. Was supposed to do. Furthermore, since these measurements are performed before processing, the vertical position of the wafer may be slightly shifted from that before processing during processing.
Further, in order to measure the cross-sectional shape of the wafer after processing, a method using a projection image as shown in FIG. 15 is generally used. However, in this method, the thickest portion as viewed from the projection position is projected and measured.
Thus, it is difficult to predict the measurement result after processing from the measurement result before processing, the processing position of the grindstone cannot be effectively corrected, and the processing accuracy of the wafer has been a problem.

Also, wafers near the beginning of the lot (ingot) at the beginning of cutting or near the end of the cutting often differ greatly from other parts, so the wafer at the beginning of the lot is processed and measured, and the grinding stone is determined according to the measurement results. Even if the processing position is corrected, other wafers in the same lot may not be processed into the target peripheral edge shape.
Further, the first wafer when the processing of the wafer of the next lot is started after the processing of the wafer of the predetermined lot is different from the wafer of the lot processed immediately before. For this reason, in addition to the wafers at the lot start end and lot end, several other wafers in the same lot cannot often be processed to the target diameter or peripheral end shape, and are discarded because they are discarded.

  The present invention has been made to solve the above problems, and it is an object to accurately correct the processing position of the grindstone in accordance with the wafer shape habit of each lot and improve the accuracy of chamfering processing of the wafer. To do.

In the present invention, means for solving the above problems are as follows.
According to a first aspect of the present invention, a grindstone is brought into contact with a peripheral end portion of a wafer that is placed on a rotary table and rotated to be chamfered to have a target diameter and target peripheral end shape. In the chamfering method of a wafer to be processed, when starting chamfering of one lot consisting of a plurality of wafers, a first step of adopting one wafer in the lot as a sample wafer, and targeting the sample wafer as a target A second step of trial processing the sample wafer by setting the position of the grindstone so as to process the sample diameter and the target peripheral edge shape larger by a predetermined dimension than the diameter to be processed. And a third step of measuring the diameter or peripheral edge shape of the sample wafer, and the grindstone based on the measurement result of the sample wafer. A fourth step for correcting the relative position with respect to the rotary table, and a target peripheral edge and a target diameter of the wafer in the lot including the sample wafer after the trial processing by the grindstone at the corrected position. And a fifth step of sequentially processing lots into shapes.

  The second invention compares the diameter or peripheral end shape measured for the sample wafer in the third step with the sample diameter or target peripheral end shape set in the second step. Then, after the fourth step and until the difference between the diameter or the peripheral edge shape measured for the sample wafer and the sample diameter or the target peripheral edge shape becomes smaller than a predetermined value, Before the fifth step, the steps from the first step to the fourth step are repeated using a wafer different from the sample wafer in the same lot as the sample wafer.

  According to a third aspect of the present invention, there is provided a sixth step of measuring the diameter or peripheral edge shape of the lot-processed wafer after lot processing in one or more of the wafers to be lot-processed, and the grindstone based on the measurement result And a seventh step of correcting the relative position to the rotary table.

  The fourth invention is characterized in that the sixth step to the seventh step are sequentially performed at intervals of a predetermined number of wafers to be lot processed.

  According to a fifth aspect of the present invention, in a method for chamfering a wafer using a plurality of turntables, different wafers in the same lot are adopted as sample wafers for each of the turntables, and steps 2 to 4 are performed. It is characterized by performing.

  In a sixth aspect of the present invention, in the first step, a wafer that is a predetermined number of wafers after the start of the lot is employed as the sample wafer.

  According to a seventh aspect of the invention, in the third step, the wafer peripheral shape is measured at a plurality of locations at a predetermined rotation angle on the circumference of the sample wafer, and in the fourth step, the shape is measured at each of the plurality of locations. The relative position of the grindstone with respect to the rotary table is corrected.

  According to an eighth aspect of the invention, there is provided a rotary table for rotating a wafer placed on the center and a grindstone for chamfering the wafer in contact with a peripheral portion of the wafer placed on the rotary table and rotated. A wafer chamfering processing apparatus, a processing position adjusting device for adjusting the relative position between the grindstone and the wafer placed on the rotary table, a measuring device for measuring the diameter and peripheral edge shape of the wafer, At the start of processing of a new lot of wafers, one wafer in this lot is adopted as a sample wafer and placed on a rotary table, and the sample diameter is set by a predetermined dimension larger than the target diameter by the grinding wheel. Trial processing is performed to the same peripheral edge shape setting as the target peripheral edge shape, and the diameter or peripheral edge shape of the sample wafer is increased. Measured by a measuring device, and based on the measurement results, the processing position adjusting device corrects the relative position of the grindstone with respect to the rotary table, and the grindstone at the corrected position includes the sample wafer after trial processing. A processing control unit for controlling the rotary table, the grindstone, the processing position adjusting device, and the measuring device so that the wafers in the lot are sequentially processed into the target diameter setting and the target peripheral edge shape setting. It is characterized by having.

  According to a ninth aspect of the invention, there is provided a temporary storage device that takes out a sample wafer that has undergone trial processing from the rotary table and stores the sample wafer until the lot processing.

  In a tenth aspect of the present invention, the grindstone is two grooveless grindstones that chamfer the wafer by simultaneously contacting a position close to the same portion of the peripheral end portion of the wafer that is placed on the rotary table and rotated. It is characterized by that.

  The eleventh aspect of the invention includes a roughening grindstone for chamfering a wafer roughly, and a fine grinding wheel for chamfering a wafer chamfered with the roughening grindstone, and the processing control unit includes: The processing position of the grinding wheel for fine polishing is corrected based on the measurement result.

  In a twelfth aspect of the invention, the machining control unit also corrects the machining position of the roughing grindstone based on the measurement result.

  According to the first aspect of the present invention, the grinding wheel is brought into contact with the peripheral end of the wafer that is placed on the rotary table and rotated and rotated, and the target peripheral diameter of the wafer is set as a target. In the method of chamfering a wafer to be chamfered, when starting chamfering of one lot consisting of a plurality of wafers, a first step of adopting one wafer in this lot as a sample wafer, A second step in which the position of the grindstone is set so as to be processed into a sample diameter and a target peripheral edge shape larger by a predetermined dimension than the target diameter, and the sample wafer is trial processed; Based on the third step of measuring the diameter or peripheral edge shape of the processed sample wafer and the measurement result of the sample wafer A fourth step of correcting the relative position of the grindstone with respect to the rotary table, and a target diameter and target circumference of the wafer in the lot including the sample wafer after the trial processing by the grindstone at the corrected position. By having a fifth step of sequentially processing lots into end shapes, the wafer in the lot including the sample wafer to be processed first can be accurately set to the target diameter and target peripheral end shape settings. Can be processed.

  According to the second invention, the diameter or the peripheral edge shape measured for the sample wafer in the third step, the sample diameter or the target peripheral edge shape set in the second step, And after the fourth step until the difference between the measured diameter or peripheral edge shape of the sample wafer and the sample diameter or the target peripheral edge shape becomes smaller than a predetermined value. Further, before the fifth step, the wafer processing accuracy is further improved by repeating the first to fourth steps by using a wafer different from the sample wafer in the same lot as the sample wafer. Can do.

  According to the third invention, on one or more of the wafers to be processed in lots, after the lot processing, the sixth step of measuring the diameter or peripheral edge shape of the processed wafers on the basis of the measurement results By performing the seventh step of correcting the relative position of the grindstone with respect to the rotary table, the processing accuracy of the wafer can be further improved.

  According to the fourth aspect of the present invention, the processing accuracy of the wafer is further improved by sequentially performing the sixth step to the seventh step at intervals of a predetermined number of wafers to be processed in lots. be able to.

  According to the fifth invention, in the method of chamfering a wafer using a plurality of turntables, different wafers in the same lot are adopted as sample wafers for each of the turntables, and the second to fourth steps are employed. By performing the steps, the wafer can be processed into a target diameter setting and a target peripheral edge shape setting with higher accuracy in a plurality of rotary tables.

  According to the sixth invention, in the first step, by adopting a wafer that is a predetermined number of wafers after the start of the lot as the sample wafer, the average shape is close to that of many wafers in the lot. A wafer having a simple shape can be used as a sample wafer, and the remaining wafer can be processed to a target dimension with higher accuracy.

  According to the seventh invention, in the third step, the wafer peripheral portion shape is measured at a plurality of locations at predetermined rotation angles on the circumference of the sample wafer, and at the plurality of locations in the fourth step. By correcting the relative position of the grinding wheel to the rotary table, the processing position of the grinding wheel can be accurately corrected at a plurality of locations for each predetermined rotation angle of the wafer, and the peripheral edge shape of the wafer can be processed more accurately. can do.

  According to the eighth aspect of the present invention, there is provided a rotary table for rotating the wafer placed on the center and a grindstone for chamfering the wafer in contact with the peripheral edge of the wafer placed on the rotary table and rotated. A chamfering apparatus for a wafer having a processing position adjusting apparatus for adjusting a relative position between the grindstone and the wafer placed on the rotary table, and a measuring apparatus for measuring the diameter and peripheral edge shape of the wafer. At the start of the processing of a new lot of wafers, one wafer in this lot is adopted as a sample wafer and placed on a rotary table, and the sample diameter is larger than the target diameter by the grinding wheel by a predetermined dimension. Trial processing to the same peripheral edge shape setting as the set and target peripheral edge shape, and the diameter or peripheral edge shape of the sample wafer that was trial processed Is measured by the measuring device, and based on the measurement result, the relative position of the grindstone with respect to the rotary table is corrected by the processing position adjusting device, and the sample wafer after trial processing is corrected by the grindstone at the corrected position. Processing control for controlling the rotary table, the grindstone, the processing position adjusting device, and the measuring device so as to sequentially perform the lot processing on the wafer in the lot including the target diameter setting and the target peripheral edge shape setting. Therefore, the wafer in the lot including the sample wafer to be processed first can be accurately processed to the target diameter and the target peripheral edge shape setting.

  According to the ninth invention, the sample wafer that has been trial-processed is taken out of the rotary table and has a temporary storage device that stores the sample wafer until the lot processing, so that the sample wafer is measured and then processed into the lot. Since it can be stored separately from unprocessed wafers or lot processed wafers, it can be stored safely without mixing with unprocessed wafers or lot processed wafers.

  According to the tenth invention, the grindstone is provided with two grooveless grindstones that chamfer the wafer by simultaneously contacting a position close to the same portion of the peripheral edge of the wafer that is placed on the rotary table and rotated. Thus, the wafer can be processed with high accuracy by the two grooveless grindstones whose processing positions are corrected.

  According to an eleventh aspect of the present invention, it has a roughing grindstone that grinds a wafer roughly, and a fine grinding grindstone that precisely grinds the wafer processed by the roughening grindstone, and the processing control unit includes the measurement By correcting the processing position of the grinding wheel based on the result, the processing position of the grinding wheel requiring higher processing accuracy is corrected, and the wafer can be processed with high accuracy.

  According to the twelfth aspect, the machining control unit also corrects the machining position of the roughening grindstone based on the measurement result, so that the machining positions of both the roughening grindstone and the fine grinding wheel are changed. It is corrected and the wafer can be processed with higher accuracy.

It is a plane explanatory view showing a chamfering device of a wafer concerning an embodiment of the present invention. It is front explanatory drawing which shows the same chamfering apparatus. It is a figure which shows a carrying-in arm, (a) is plane explanatory drawing, (b) is front explanatory drawing. It is side explanatory drawing which shows the chamfering process using an edge rough grindstone. It is perspective explanatory drawing which shows the rough grinding wheel support apparatus of the edge rough grinding wheel and the grindstone for notches. It is a perspective enlarged view which shows the chamfering process using an edge precision grinding wheel, (a) shows the chamfering process of the wafer which has a notch, (b) shows the chamfering process of the wafer which has an orientation flat. It is a front view which shows the grindstone support apparatus of an edge fine grinding grindstone. It is a side view which shows the grindstone support apparatus of an edge fine grinding grindstone. It is front explanatory drawing which shows the other chamfering process using an edge fine grinding wheel. It is a figure which shows a carrying-out arm, (a) is plane explanatory drawing, (b) is front explanatory drawing. It is a timing chart at the time of chamfering a wafer with a chamfering apparatus. It is a figure which shows the planar shape of a wafer, (a) is a wafer which has a notch, (b) is a wafer which has an orientation flat. It is a figure which shows the cross-sectional shape of the wafer by a chamfering process. It is a figure which shows the cross-sectional shape of the other wafer by a chamfering process. It is a perspective view which shows the sensor which image | photographs the projection image of a wafer peripheral edge part, and measures a peripheral edge part shape. (A) is plane explanatory drawing which shows the wire mark of a wafer, (b) is the arrow enlarged view seen from the SS direction in (a). It is plane explanatory drawing which shows the measurement item of the 3rd step in the wafer which has a notch. It is plane explanatory drawing which shows the measurement item of the 3rd step in the wafer which has an orientation flat. It is a side view which shows the chamfering method of the wafer which concerns on embodiment of this invention, (a) shows the case where a wafer peripheral edge part has no curvature, (b) shows the case where a wafer peripheral edge part has curvature. ing. It is a top view which shows the chamfering method of the wafer which concerns on embodiment of this invention, (a) shows the case of the wafer which has a notch, (b) has shown the case of the wafer which has an orientation flat.

Hereinafter, a wafer chamfering apparatus according to an embodiment of the present invention will be described.
As shown in FIG. 1, this chamfering apparatus has a plurality of turntables 2 on which a wafer 1 is placed, and has different processing characteristics (roughness, wafer processing locations, etc.) corresponding to a plurality of chamfering processes. It has a plurality of grindstones 3, 4, 5, and each grindstone 3, 4, 5 is movable between each rotary table 2 A, 2 B, 2 C, 2 D.
Similarly, the sensors 7, 8 and 9, the illuminator 50, the CCD camera 51, the cleaning mechanism 10, and the drying mechanism 11 that measure, clean and dry the wafer 1 before and after the chamfering process are respectively connected to the rotary tables 2A and 2B. It can move between 2C and 2D.

  As shown in FIG. 1, this chamfering apparatus includes two cassettes 12 and 12 for storing an unprocessed wafer 1 and four rotary tables 2 (2A to 2D) for placing the wafer 1 and chamfering it. ), Two cassettes 13 and 13 for storing processed (lattice processed later) wafers 1, and a temporary placement cassette 40 for temporarily placing sample wafers after trial processing described later. Have.

Further, the chamfering apparatus includes a cassette arm 14 for carrying in / out the wafer 1 to / from each cassette 12, 13, 40, and receiving the wafer 1 from the cassette arm 14 to each rotary table 2A, 2B, 2C, 2D. A loading arm 15 to be placed and a carry-out arm 16 for delivering the wafer 1 placed on each rotary table 2A, 2B, 2C, 2D to the cassette arm 14 are provided.
Further, for the chamfering of the wafer 1, the chamfering apparatus includes an edge roughing grindstone 3 made of a rough grindstone for rough grinding of the edge 1a of the wafer 1 and a contouring processing of the edge 1a of the wafer 1 (precision research). ) And a notch grinding wheel 5 made of a general grinding wheel for machining the notch 1n.
In the case of a wafer having an orientation flat 1 f, the orientation flat 1 f is processed by the edge rough grinding stone 3 and the edge precision grinding stone 4. Further, in this embodiment, only the rough grinding of the notch 1n is performed by the notch grindstone 5, and the fine grinding of the notch 1n is performed by another apparatus after finishing the machining by the chamfering apparatus of the present embodiment.

As shown in FIG. 1, the four rotary tables 2A, 2B, 2C, and 2D are arranged in series on a substantially straight line. Hereinafter, this arrangement direction is referred to as an X-axis direction. Further, the horizontal direction orthogonal to the X-axis direction is referred to as the Y-axis direction, and the height direction is referred to as the Z-axis direction. As shown in FIG. 2, the rotary table 2 (the rotary tables 2A, 2B, 2C, and 2D are A stage 17 on which the wafer 1 is centered and placed is provided at the upper part of the “rotary table 2”. The stage 17 is formed with a smaller diameter than the wafer 1 and has a suction chuck for fixing the mounted wafer 1 with a negative pressure.
As shown in FIGS. 2 and 7, the rotary table 2 is provided with a rotary table rotating mechanism 18 that rotates the stage 17 using a motor, and the stage 17 is rotated when the wafer 1 is chamfered. The edge 1a of the wafer 1 placed on the stage 17 can be chamfered over the entire circumference. Further, the turntable 2 can be moved in the Y-axis direction by a turntable approaching / separating mechanism 19 composed of a rail, a ball screw, or the like, and the wafer 1 placed on the stage 17 is moved to each of the grindstones 3, The chamfering process can be performed while being closely spaced from 4,5.

As shown in FIG. 1, a cassette 12 for storing unprocessed wafers 1, a cassette 13 for storing processed wafers 1, and a temporary storage cassette 40 are also arranged along the X-axis direction. .
A cassette arm 14 is provided between a row of four cassettes 12 and 13 and a temporary placement cassette 40 and a row of four rotary tables 2A, 2B, 2C, and 2D. The cassette arm 14 has a substantially Y-shaped arm portion 14a for carrying the wafer 1 thereon. Further, as shown in FIG. 2, the cassette arm 14 is provided with a cassette arm X-axis moving mechanism 20 that is guided by the support column 37 and moves in the X-axis direction, and moves the arm portion 14a in the Y-axis direction. There are provided a cassette arm Y-axis moving mechanism 21 for moving the cassette arm, a cassette arm raising / lowering mechanism 22 for raising and lowering the arm portion 14a, and a cassette arm turning mechanism 23 for turning horizontally.

As shown in FIGS. 2 and 3, the carry-in arm 15 has an arm portion 15 a that is hung from the ceiling near the turntable 2 and extends in the horizontal direction. A suction chuck 15b that sucks the wafer 1 from above by a negative pressure is provided at the tip of the arm portion 15a, and the wafer 1 can be held by the suction chuck 15b. As shown in FIG. 3B, a direct drive motor 15c is provided immediately above the chucking chuck 15b, and the held wafer 1 can be rotated and measured in the circumferential direction to be measured and placed as described later.
The carry-in arm 15 is provided with a carry-in arm moving mechanism 24 (FIG. 2) for moving in the X-axis direction and a carry-in arm raising / lowering mechanism (not shown) for raising and lowering the arm portion 15a. The wafer 1 can be transferred to the turntable 2.

Further, as shown in FIG. 3, the carry-in arm 15 has a pair of upper and lower diameters (D in FIG. 12) or radius (same R), center, notch 1n at substantially the same height as the arm portion 15a. Alternatively, an alignment sensor 7 for measuring the position of the orientation flat 1f is provided (the alignment sensor 7 is omitted in FIG. 2).
As shown in FIG. 3A, the alignment sensor 7 is pivotably attached to the loading arm 15. Therefore, when the wafer 1 is sucked by the suction chuck 15b and when the wafer 1 is transferred from the suction chuck 15b, the alignment sensor 7 is aligned. The sensor 7 can be released so as not to contact the wafer 1, and the wafer 1 can be measured by rotating the alignment sensor 7 up and down the wafer 1 while the loading arm 15 holds the wafer 1. Further, an alignment sensor elevating mechanism (not shown) for elevating the alignment sensor 7 with respect to the loading arm 15 is provided, and the height of the alignment sensor 7 can be adjusted when measuring the wafer 1.
The carry-in arm 15 rotates the wafer 1 based on the circumferential angle of the wafer 1 set from the measurement result of the alignment sensor 7 and places it on the turntable 2 at a desired placement angle. At this time, centering is performed so that the center of the wafer 1 and the center of the stage 17 of the turntable 2 coincide.

Further, the carry-in arm 15 is provided with a pair of upper and lower thickness sensors 8 below the arm portion 15a, and after the wafer 1 is placed on the turntable 2, the heights of the upper and lower surfaces of the wafer 1 are measured. The thickness of the wafer 1 is detected from the difference.
Note that the thickness sensor 8 may be configured to measure the thickness of the wafer 1 while the carry-in arm 15 holds the wafer 1.

As shown in FIGS. 4 and 5, the edge roughing grindstone 3 is a horizontal general-purpose grindstone in which a groove having a shape matching the required cross-sectional shape of the wafer 1 is formed on the peripheral end surface. The rotary table 2 is moved in the Y-axis direction by the rotary table approaching / separating mechanism 19 while rotating at different rotational speeds opposite to the table 2, and the edge 1 a of the wafer 1 is pressed against the groove of the grindstone 3. 1 edge 1a is roughed.
As shown in FIG. 5, the notch grindstone 5 is a general grindstone in which a groove having a shape matching the notch shape required for the wafer 1 is carved on the peripheral end surface in the same manner as the edge rough grindstone 3. The rotary table 2 is moved in the Y-axis direction by the rotary table approaching / separating mechanism 19 and the notch grindstone 5 is moved in the X-axis direction by the rough grindstone moving mechanism 27 described later, while being rotated in the same direction as the edge rough grindstone 3. Then, grinding is performed along the required shape of the notch 1n.
As shown in FIGS. 2 and 5, the edge roughing grindstone 3 and the notch grindstone 5 are attached to one grindstone support device 26 to chamfer the wafer 1. As shown in FIG. 1, the grindstone support device 26 is attached to the upper portion of the side wall 29 of the chamfering device, and the rough grindstone moving mechanism 27 for moving in the X-axis direction and the rough grindstone lifting mechanism 28 for moving up and down. have. As an example, the rough grinding wheel moving mechanism 27 can be configured by using a ball screw including a screw shaft in the X-axis direction attached to the side wall 29 and a nut attached to the grinding wheel support device 26 as a driving force. it can. Similarly, the rough grinding stone lifting mechanism 28 can also be configured using a ball screw.

As shown in FIG. 6, the edge fine grinding wheel 4 is composed of a pair of vertical disk-shaped grooveless grinding stones 4a and 4a facing each other in the vicinity, and each of them is rotated in the opposite direction to rotate horizontally. The chamfering process of the edge 1a is performed by pressing against the wafer 1 to be performed.
Therefore, as shown in FIGS. 2, 7, and 8, the edge polishing wheel 4 is supported by the wheel support device 30, and each of the wheels 4a and 4a is attached to the wheel support device 30 via a spindle motor that rotates the wheel. It is attached. Moreover, while providing the support apparatus raising / lowering mechanism 31 which raises / lowers the grindstone support apparatus 30 whole, the pair of edge fine grinding stone raising / lowering mechanisms 32 and 32 which raise / lower each grindstone 4a, 4a are provided, and each grindstone 4a, 4a is provided. The edge 1a of the wafer 1 can be chamfered while maintaining the same height (FIG. 6). However, the heights of the grindstones 4a and 4a are made different so that the wafer 1 is sandwiched from above and below the upper slope 1au and It is also possible to chamfer the lower slope 1ad (FIG. 9).
As shown in FIG. 2, the grindstone support device 30 for attaching the edge fine grinding stone 4 is assembled to the lower portion of the side wall 29 of the chamfering device, and has an edge fine grinding stone moving mechanism 33 for moving in the X-axis direction. Yes. As an example, the edge precision grinding wheel moving mechanism 33 is configured by using a ball screw including a screw shaft in the X-axis direction attached to the side wall 29 and a nut attached to the grinding wheel support device 30 as a driving force. Can do.

As shown in FIGS. 2 and 10, the carry-out arm 16 is hung from the ceiling side on the side wall 29 side in the vicinity of the turntable 2, and has an arm portion 16 a protruding in the horizontal direction. Is provided with an adsorption chuck 16b that adsorbs the wafer from above by a negative pressure, so that the wafer 1 can be held. A direct drive motor 16c is provided immediately above the suction chuck 16b, and the held wafer 1 can be rotated in the circumferential direction to be cleaned, dried and measured as described later.
The carry-out arm 16 includes a carry-out arm moving mechanism 38 for moving in the X-axis direction, a carry-out arm raising / lowering mechanism (not shown) for raising and lowering the arm portion 16a, and a carry-out arm turning mechanism (not shown) for turning the arm portion 16a. ) Is provided, and the wafer 1 that has been processed from each rotary table 2 to the cassette arm 14 or after trial processing described later can be transferred.

As shown in FIG. 10, the carry-out arm 16 includes a cleaning mechanism 10 including upper and lower three water nozzles 10a, 10b, and 10c, and a drying mechanism 11 including upper and lower three air nozzles 11a, 11b, and 11c. Yes. When the wafer 1 is held by the arm portion 16a of the carry-out arm 16, the upper water nozzle 10a and the air nozzle 11a are installed so as to be inclined downward and above the wafer 1, and the upper surface of the wafer 1 is cleaned and dried. The water nozzle 10b and the air nozzle 11b in the middle stage are installed so as to be inclined upward and below the wafer 1, and the lower surface of the wafer 1 is cleaned and dried. The lower water nozzle 10c and the air nozzle 11c are installed to be inclined downward, and the stage 17 of the turntable 2 is washed and dried.
In this embodiment, the cleaning mechanism 10 and the drying mechanism 11 are arranged so that the stage 1 of the rotary table 2 can be cleaned and dried while holding the wafer 1 above the rotary table 2 and cleaning and drying the wafer 1. However, the wafer 1 may be cleaned and dried with the wafer 1 placed on the turntable 2.

Further, the unloading arm 16 is provided with a post-processing sensor 9 which is composed of a pair of upper and lower members and measures the radius of the wafer 1, the shape of the notch 1n or the orientation flat 1f. After processing, the sensor 9 irradiates a laser beam from the upper side and detects that this is blocked by the wafer 1 placed on the stage 17, and the shape of the peripheral end surface 1b and the notch 1n or the orientation flat 1f of the wafer 1 is determined. The radius of the wafer 1 is detected from the distance from the center of the wafer 1 by measurement.
Since the post-processing sensor 9 is pivotally attached to the carry-out arm 16, in order to measure the shape of the wafer 1, first, the post-process sensor 9 is placed directly above the wafer 1 with the carry-out arm 16 holding the wafer 1. Escape from. Next, the height of the arm portion 16a is raised to the height of the post-processing sensor 9, and the post-processing sensor 9 is swung and placed on the top and bottom of the wafer 1, whereby the shape of the wafer 1 can be measured. Further, the post-processing sensor 9 is provided above the cleaning mechanism 10 or the drying mechanism 11 so as not to become dirty when the wafer 1 is cleaned or dried. In addition, the post-processing sensor 9 may be configured to measure the shape of the wafer 1 while the wafer 1 is placed on the turntable 2.
As shown in FIGS. 10 and 15, a sensor for irradiating parallel light from the illuminator 50 to the vicinity of the edge 1a of the wafer 1 and receiving it by the CCD camera 51 is attached to the carry-out arm 16 as shown in FIGS. Is measured using this sensor after being rotated to a predetermined position, whereby the cross-sectional shape of the edge 1a at any position on the entire circumference of the wafer 1 can be measured.

Next, a chamfering method of the wafer 1 and control of each part in this chamfering apparatus will be described.
When the wafer chamfering processing apparatus starts processing a wafer in a new lot, the wafer 1 is subjected to test processing using the wafer 1 as a sample wafer, and the processing position of the grindstone is corrected based on the result of the test processing. Then, the lot processing of the sample wafer and the remaining wafers 1 in the lot is sequentially performed.

To start chamfering of a new lot of wafers 1, first, a cassette in which a plurality of wafers are stored while maintaining the order from the lot start end to the lot end, which is a part of one lot consisting of many wafers. One wafer 1 out of 12 is adopted as a sample wafer (first step).
The reference for selecting the sample wafer is recorded in advance in the processing control unit of the chamfering apparatus, and the user inputs information such as the number of wafers 1 in the lot, and the lot information is obtained from the input information and the above-mentioned reference. It may be calculated how many wafers 1 from the starting edge are used as sample wafers.
Since the sample wafer serves as a reference for correcting the processing position of the grindstone, it is preferably close to the average shape of the wafers 1 in the lot. Therefore, it is preferable that the processing control unit set the wafer 1 after a predetermined number of wafers from the start of the lot as the sample wafer. For example, the wafer 1 located at the center of the lot can be used.
Further, it may be recorded in advance in the processing control unit that the user does not need to input information and the nth wafer 1 from the start of the lot is used as a sample wafer.

When the sample wafer is determined, the sample wafer is taken out from the cassette 12 in which the wafer 1 as a part of the lot is stored by the cassette arm 14 and transferred from the cassette arm 14 to the carry-in arm 15.
In the carry-in arm 15 that has received the sample wafer, as shown in FIG. 3, the sample wafer is placed on any one of the rotary tables 2A, 2B, 2C, and 2D at a correct placement position based on the measurement of the alignment sensor 7, A thickness sensor 8 measures the thickness of the sample wafer (wafer 1).

Next, the sample wafer on the turntable 2 is subjected to trial processing from the original shape E0 (see FIGS. 19 and 20) (second step).
In the second step, the sample wafer has a sample diameter larger than the target diameter by a predetermined dimension, and the peripheral edge (edge) of the wafer 1 made of α1, α2, R1, R2, X1, X2, and X3. 1a) The cross-sectional shape, the depth and forming angle of the notch 1n, the notch shape including the cross-sectional shape or the shape of the orientation flat 1f (collectively referred to as the peripheral end shape) is finally set as the target peripheral end shape. Processing is performed (E1 in FIGS. 19 and 20).
The set diameter for the sample is set to a dimension that can be processed into a target diameter and a target peripheral end shape in the lot processing even if excessive grinding occurs in the trial processing.
In this trial processing, the sample wafer is processed with the edge rough grinding wheel 3, the edge precision grinding stone 4, and the notch grinding stone 5.

When the trial processing is completed, as shown in FIG. 10, the third step of holding the sample wafer on the carry-out arm 16 and measuring the diameter and the peripheral end shape by the post-processing sensor 9, the illuminator 50, and the CCD camera 51 is performed. Do.
In the first example of the measurement item, the diameter D (FIG. 12) of the sample wafer subjected to trial processing, and α1, α2, R1, R2, X1, X2, and X3 (FIGS. 13 and 14) of the peripheral edge (edge 1a). ).
As a second example, in the case of a sample wafer having an orientation flat 1f, as shown in FIGS. 18, 13, and 14, the diameter D of the sample wafer that has been trial-processed, the length W2 of the orientation flat 1f, the orientation Arc-shaped radii LR and RR connecting the flat 1f and the other peripheral end (edge 1a), and X1, X2 and X3 of the cross-sectional shape of the orientation flat 1f may be measured. In FIG. 18, W represents the distance between the intersections of the extension line of the orientation flat 1f and the virtual circle obtained from the other peripheral edge (edge 1a), and can be obtained by calculation from the measured value.
As a third example, in the case of a sample wafer having a notch 1n, as shown in FIG. 17, the diameter D (FIG. 12) of the sample wafer subjected to trial processing, the depth Nd of the notch 1n, and the formation angle of the notch 1n. Nθ, the arc-shaped radius BR of the deepest part of the notch 1n, the arc-shaped radii LR, RR connecting the notch 1n and the other peripheral end 1a, and the cross-sectional shapes X1, X2, X3 of the notch 1n (FIG. 13, You may make it measure (refer FIG. 14). In FIG. 17, W indicates the distance between the intersections of the straight line extension line of the notch 1n and the virtual circle obtained from the other peripheral edge 1a, and can be obtained by calculation from the measured value. Further, P1 indicates the distance between the virtual circle obtained from the other peripheral edge 1a and the inscribed circle having a predetermined radius of the notch 1n, and P2 indicates the maximum distance from the deepest part of the notch 1n to the inscribed circle. , Both can be calculated from the measured values.
In the third step, it is preferable to measure the shape of the peripheral edge of the wafer at a plurality of locations at predetermined rotation angles on the periphery of the sample wafer that has been subjected to trial processing. For example, as shown in FIG. 16A, in the present embodiment, the shape of the peripheral edge of the wafer is measured at 8 points every 45 degrees from A to H with reference to the notch.

Next, a fourth step of correcting the relative positions of the edge roughing grindstone 3, the edge precision grindstone 4 and the notch grindstone 5 with respect to the rotary table based on the measurement result is performed.
In the fourth step, the grindstone 3 is determined based on the difference between the diameter of the sample wafer that has been trial processed and the set diameter for the sample, and the difference between the peripheral end shape of the sample wafer that has been trial processed and the target peripheral end shape. 4 and 5 or the coordinate positions of the X-axis, Y-axis, Z-axis, and θ-axis are corrected. Coordinates when machining with the grindstones 3, 4, and 5 are expressed by the following functions.
X = FnX (Xn, Rn, D,...)
Y = FnY (Yn, Rn, D,...)
Z = FnZ (Zn, Rn, Hn, t, h, D,...)
θ = Fnθ (θn, Rn, D,...)
Where
Xn, Yn, Zn, θn are teaching coordinates for each coordinate of the grindstone n,
Rn is the radius of the grinding wheel n,
Hn is the groove position of the grindstone n (in the case of an overall grindstone),
t is the measured wafer thickness before processing,
h is the measured wafer height before processing,
D, ... are the target diameter for the sample and various target dimensions of the peripheral edge shape.
Here, if various measured values of the sample wafer that has been trial processed are D ′,..., The correction values ΔXn, ΔYn, ΔZn, Δθn, ΔRn, ΔHn are:
ΔXn = FnXD (D′−D)
ΔYn = FnYD (D′−D)
ΔZn = FnZD (D′−D, t, h)
Δθn = FnθD (D′−D)
ΔRn = FnRD (D′−D)
ΔHn = FnHD (D′−D, t, h)
Thus, the equation to be obtained is different for each correction value. Some functions always have a value of 0 depending on the type of correction value.
When correcting the grindstones 3, 4, and 5, the positions of the grindstones 3, 4, and 5 are corrected based on the measurement results at every 8 points measured every 45 degrees in the third step, and the machining control unit This correction position information is recorded in the recording section. This configuration reduces the amount of measurement results and recorded correction position information data without degrading the chamfering accuracy of the wafer, compared to the case where measurement is performed over the entire circumference of the wafer and correction position information is recorded. can do.
As another example, the position of the edge roughening grindstone 3 may be corrected without correcting the position of the edge roughening grindstone 3. Thus, by performing position correction only at the time of precision grinding of the wafer, it is possible to maintain the chamfering accuracy of the wafer while reducing the control man-hour by the processing control unit.

Since the chamfering apparatus has a plurality of turntables 2A to 2D, each of the turntables 2 employs each different wafer 1 in the lot as a sample wafer (first step), and performs the second to fourth steps. Do.
For this reason, the edge rough grinding wheel 3, the edge precision grinding stone 4 and the notch grinding stone 5 move between the rotary tables 2A to 2D, but the grinding stone 3 corrected in the fourth step in the specific rotary table 2 is provided. The position information of 4 and 5 is recorded in the recording unit for each of the rotary tables 2A to 2D provided in the processing control unit, and when performing lot processing (fifth step) described later on the rotary tables 2A to 2D. Each time the position information is read out, the grindstones 3, 4, and 5 are set according to the position information.
“Correcting” the position of the grindstone in the fourth step means that the grindstones 3, 4 and 5 are moved based on the measurement result of the third step in addition to moving the grindstones 3, 4, and 5 to the corrected positions. 5 correction positions are calculated, and the position information is recorded in the machining control unit.

Further, in each rotary table 2, the difference between the diameter of the sample wafer measured after the trial processing in the third step and the set diameter for the sample, or the peripheral edge shape of the sample wafer subjected to the trial processing and the target peripheral edge When the difference from the part shape is larger than the predetermined value, after the fourth step is finished, another wafer 1 in the same lot is newly set as a sample wafer, and again from the first step to the fourth step. May be performed.
The first sample wafer first trial processed is temporarily placed in the temporary cassette 40 by the carry-out arm 16 and the cassette arm 14 before placing the newly adopted second sample wafer on the turntable 2. Stored.
In the third step again, the difference between the diameter of the sample wafer measured after the trial processing and the set diameter for the sample, or the peripheral edge shape of the sample wafer measured after the trial processing and the target peripheral edge shape, If the difference is equal to or greater than a predetermined value, another wafer 1 in the same lot is further set as a new sample wafer, and the first to fourth steps are repeated.
In the third step, the difference between the diameter of the sample wafer measured in the third step and the set diameter for the sample, and the difference between the peripheral edge shape of the sample wafer and the target peripheral edge shape are predetermined values. When it becomes smaller, after the fourth step immediately after the end, the process proceeds to a fifth step to be described later.

Even when adopting the first sample wafer for each turntable 2 or when adopting the second and subsequent sample wafers, avoid the wafer 1 at the start of the lot, and select the wafer 1 close to the average shape of the wafers in the lot. It is preferable to adopt them preferentially.
In this case, the priority order adopted as the sample wafer from the lot or the determination method thereof is recorded in advance in the processing control unit.

Then, using the edge roughing grindstone 3, the edge fine grinding wheel 4 and the notch grindstone 5 at the position corrected in the fourth step, the wafer 1 in the lot including the sample wafer is set to a target diameter and a target. Then, lot processing is sequentially performed on the peripheral end shape E2 (see FIGS. 19 and 20) (fifth step).
When lot processing of the wafer 1 is performed, the grindstone is arranged at the position of the correction position information recorded in the fourth step at 8 positions A to H every 45 degrees on the circumference of the wafer 1, and the 8 positions A to H are set. At the middle position of H, the position of the grindstone is gradually changed.
The order of lot processing on each turntable 2 follows the order from the start side to the end side of the lot regardless of whether or not it is adopted as a sample wafer. Here, among a large number of wafers 1, a wafer 1 that has been adopted as a sample wafer and subjected to trial processing is stored in a temporary cassette 40, and a wafer that has not been adopted as a sample wafer and has not been subjected to trial processing is stored in two cassettes. 12. Accordingly, the cassette arm 14 sequentially takes out the wafers 1 from one of the two cassettes 12 and the temporary placement cassette 40 according to the order from the start side to the end side of the lot, and transfers them to the carry-in arm 15. It is carried out.

  In this lot processing, the first chamfering process, the second chamfering process, the third chamfering process, and the fourth chamfering process, which will be described later, are sequentially repeated for each turntable 2 to efficiently perform wafers on the four turntables 2. 1 can be chamfered.

  In the first chamfering process, the unprocessed wafer 1 is taken out from the cassette 12 by the cassette arm 14 and received by the carry-in arm 15 (see FIG. 2), and the turntable 2 at the correct placement position based on the measurement of the alignment sensor 7. The thickness of the wafer 1 is measured by the thickness sensor 8 (see FIG. 3).

In the second chamfering step, the grinding wheel support device 26 is moved in the X-axis direction to the position of the rotary table 2 by the rough grinding wheel moving mechanism 27, and the rotary table 2 is moved closer to the grinding wheel support device 26 by the rotary table approaching / separating mechanism 19. The edge 1a of the wafer 1 is chamfered with the edge roughing grindstone 3, and then the notch 1n is chamfered with the notch grindstone 5 (see FIG. 5).
Here, when performing the precise machining while moving the position of the edge roughing grindstone 3 or the notch grindstone 5 with respect to the wafer 1 in the X-axis direction, the rough grindstone moving mechanism 27 can accurately move it.

In the third chamfering process, the grinding wheel support device 30 is moved in the X-axis direction to the position of the rotary table 2 by the edge precision grinding wheel moving mechanism 33, and the rotary table 2 is moved closer to the grinding wheel support device 30 by the rotary table approaching / separating mechanism 19. Then, the edge 1a of the wafer 1 is chamfered with the edge precision grinding wheel 4 (see FIGS. 6 and 7).
Here, when the precision machining is performed while moving the position of the edge fine grinding wheel 4 with respect to the wafer 1 in the X-axis direction, the edge fine grinding stone moving mechanism 33 can precisely move the edge fine grinding stone 4.

In the fourth chamfering step, the unloading arm 16 sucks the processed wafer 1 on the rotary table 2 and rotates the rotary table 2 while cleaning the wafer 1 and the rotary table 2, drying them, and processing the sensor 9, The shape of the wafer 1 is measured by the illuminator 50 and the CCD camera 51 (see FIG. 10), and the wafer 1 is transferred from the carry-out arm 16 to the cassette arm 14 and stored in the cassette 13 (see FIG. 2).
In this chamfering apparatus, the construction time of the first chamfering process, the second chamfering process, the third chamfering process, and the fourth chamfering process is about 80 to 120 seconds, and the variation of the construction time is reduced.

FIG. 11 is a timing chart for chamfering the wafer 1 with the chamfering apparatus. In FIG. 11, the vertical direction represents each rotary table 2, and the horizontal direction represents elapsed time.
Hereinafter, the four turntables 2 are distinguished as turntables 2A, 2B, 2C, and 2D.
In this chamfering apparatus, when chamfering is started from a state in which the wafers 1 are not placed on all the turntables 2, first, the wafer on the most lot start end side stored in the cassette 12 or the cassette 40 on the turntable 2A. the first chamfering step for 1 ₁ is performed (t1).

When it is completed, then, at the same time when the second chamfering step for the wafer 1 ₁ is performed, the first chamfering step from the lot starting side in the turntable 2B for the second sheet of the wafer 1 ₂ is carried out in a rotary table 2A ( t2).
Rotary table 2A, when the operation of the 2B is both complete, then at the same time a third chamfering step for the wafer 1 ₁ is performed at a rotation table 2A, the second chamfering step for the wafer 1 ₂ is carried out by rotating table 2B, Further, a first chamfering process is performed on the _third wafer 13 from the lot start end side on the turntable 2C (t3).

When the operation of the rotary table 2A~2C is completed, then, at the same time the fourth chamfering step for the wafer 1 ₁ is performed at a rotation table 2A, the third chamfering step for the wafer 1 ₂ is carried out by rotating table 2B, second chamfering step for the wafer 1 ₃ is performed in the rotary table 2C, the first chamfering step from the lot starting side for 4th wafer 1 ₄ is performed by the rotary table 2D (t4).
When this operation on all of the rotary table 2A~2D completed, then, take place first chamfering step from the rotary table 2A in lots starting side for 5 th wafer 1 _5, a new wafer 1 ₅ chamfering To start. At the same time, the fourth chamfering step for the wafer 1 ₂ is carried out by rotating the table 2B, a third chamfering step for the wafer 1 ₃ is performed in the rotary table 2C, a second chamfering step for the wafer 1 ₄ is performed by the rotary table 2D ( t5).

Thereafter, the steps from the first chamfering process to the fourth chamfering process are sequentially repeated in each rotary table 2, and different processes depending on the grindstone or the like are performed in parallel in each rotary table 2.
Each grindstone 3, 4, 5, carry-in arm 15, and carry-out arm 16 approaches one rotary table 2 to process or process the wafer 1, and then sequentially moves to another rotary table 2 to process or process it. I will repeat that. In the movement between the rotary tables 2, the grindstone support device 26 and the grindstone support device 30, and the carry-in arm 15 and the carry-out arm 16 may pass each other. , So that they can pass each other without contact (FIG. 2).

  Further, in the fourth chamfering process (FIG. 11) performed by the carry-out arm 16 for the wafer to be lot processed regardless of whether it is a sample wafer at the time of lot processing in the fifth step, the same as the third step. Then, the diameter or the peripheral edge shape of the wafer processed in the lot by the post-processing sensors 9, 50, 51 of the unloading arm 16 is measured (sixth step), and the measurement result and the target diameter are measured in the same manner as the fourth step. Alternatively, the relative positions of the edge rough grinding wheel 3, the edge precision grinding stone 4 and the notch grinding stone 5 with respect to the rotary table 2 are corrected from the difference from the peripheral end shape (seventh step). Based on this corrected position, the subsequent wafers 1 are processed in a lot. Although the positional relationship between the wafer and the grindstone is corrected by using the sample wafer, the difference in diameter and shape (E0) between the sample wafer and other wafers before processing, wear of the grindstone, temperature change, etc. For this reason, it is conceivable that chamfering cannot be performed to the target diameter and peripheral edge shape of all the wafers in the lot with the positional relationship adjusted with respect to the sample wafer. Therefore, by providing these steps, even if there is a difference in diameter and shape between the sample wafer and other wafers, wear of the grinding wheel, temperature change, etc., the target diameter and peripheral edge of all the wafers in the lot are targeted. It can be chamfered into a part shape. Thereby, the position of a grindstone is correct | amended according to the difference of the shape before the process for every wafer 1 by the wire mark M (refer Fig.16 (a)), and the processing precision of the wafer 1 can be improved.

Further, it is more preferable that the wafers 1 to be subjected to the sixth step to the seventh step at the time of lot processing are selected not at all the wafers in the lot but at a predetermined interval of every other number. When all wafers in one lot are chamfered sequentially in the order from the start to the end of the lot, the shape before chamfering (unprocessed) of one wafer and the next wafer to be chamfered ( 19 and FIG. 20, the difference between E0) is small, so it is not efficient to perform all of the wafers in the lot from the sixth step to the seventh step. By performing the steps from the step to the seventh step, the chamfering accuracy of the wafer 1 can be improved more efficiently.
In addition, in the lot processing of wafers in which the sixth to seventh steps are not performed, the measurement time is reduced without impairing the chamfering accuracy of all the wafers in the lot by omitting the post-processing measurement in the fourth chamfering process. Can be shortened. This is effective in increasing the production efficiency when the processing time of the fourth process is longer than the other first, second and third processes.

In the chamfering apparatus of the present embodiment, the sample wafer is trial-processed to a sample diameter larger than the target diameter and the target peripheral end shape, and the diameter and peripheral end shape of the sample wafer after the test processing are measured. Then, by correcting the relative position of the grindstones 3, 4, and 5 with respect to the rotary table 2 based on the measurement result, the wafer 1 is accurately processed to the target diameter setting and target peripheral edge shape setting in the lot processing. can do.
For this reason, when there is no warp on the plate surface of the wafer 1, not only the processing accuracy can be improved (FIG. 19 (a) E0 to E2), but also the trial processing is performed due to the warp on the plate surface of the wafer 1. Even when the target peripheral edge shape cannot be formed in (E1 in FIG. 19B), by correcting the position of the grindstone based on this error, the target peripheral edge of the wafer 1 with high accuracy is obtained. It can be processed into a part shape (E2 in FIG. 19B). In FIG. 19, E0 indicates the diameter of the wafer 1 before chamfering and the peripheral end shape of the edge 1a, E1 indicates the diameter of the trial processed wafer and the peripheral end shape of the edge 1a, and E2 indicates the target. A diameter and a peripheral end portion shape are shown.
For this reason, the sample wafer used for the trial processing is also subjected to lot processing after correcting the positions of the grindstones 3, 4, and 5 without being discarded, so that the target diameter setting and the target peripheral edge shape setting are performed. It can be processed with high accuracy.

  Further, in the plurality of turntables 2, sample wafers are subjected to trial processing for each turntable 2 and the positions of the grindstones 3 and 4 are corrected, whereby a large number of wafers 1 are chamfered using the plurality of turntables 2. Even in this case, each turntable 2 can process the wafer 1 to a target diameter setting and a target peripheral edge shape setting with high accuracy.

  Further, from the first step to the fourth step until the difference between the set dimension of the trial processing in the second step and the dimension of the wafer 1 after the trial processing measured in the third step becomes smaller than a predetermined value. By repeating the above, the processing position of the grindstones 3, 4, and 5 can be finely adjusted to a more desirable position, and the wafer 1 can be processed to a target diameter setting and target peripheral edge shape setting with higher accuracy.

  Furthermore, in the third step, the shape of the peripheral edge of the wafer is measured at a plurality of locations at predetermined rotation angles on the circumference of the sample wafer, and the processing positions of the grindstones 3 and 4 are corrected at each of the plurality of locations in the fourth step. By doing this, it is possible to efficiently set the target diameter and target peripheral edge shape over the entire circumference of the wafer efficiently without correcting the measurement results and the grinding wheel processing position correction over the entire circumference of one wafer. Can be processed.

  In addition, since the chamfering apparatus is provided with a temporary cassette 40 as a temporary storage apparatus for storing the sample wafer after the trial processing, the sample wafer can be obtained even when the first to fourth steps are repeated several times. It can be stored safely until lot processing without mixing into unprocessed wafers or lot processed wafers.

DESCRIPTION OF SYMBOLS 1 Wafer 1a Edge 1b Peripheral end surface 1n Notch 1f Orientation flat 2A, 2B, 2C, 2D Rotary table 3 (Rough edge) Grinding wheel 4 (Edge fine study) Grinding wheel 4a (Without disk type groove) Grinding wheel 5 (For notch) Grinding wheel 7 (Alignment) sensor 8 (Thickness) sensor 9 (After processing) Sensor 10 Cleaning mechanism 10a-c Water nozzle 11 Drying mechanism 11a-c Air nozzle 12 Cassette 13 Cassette 14 Cassette arm 14a Arm part 15 Loading arm 15a Arm part 15b Adsorption Chuck 15c Direct drive motor 16 Unloading arm 16a Arm portion 16b Adsorption chuck 16c Direct drive motor 17 Stage 18 Rotary table rotating mechanism 19 Rotary table approaching / separating mechanism 20 Cassette arm X-axis moving mechanism 21 Set arm Y axis moving mechanism 22 Cassette arm lifting mechanism 23 Cassette arm turning mechanism 24 Carrying arm moving mechanism 26 Grinding wheel support device 27 Coarse grinding wheel moving mechanism 28 Coarse grinding wheel lifting mechanism 30 Grinding wheel support device 31 Support device lifting mechanism 32 Edge Precision Grinding wheel lifting mechanism 33 Edge precision grinding wheel moving mechanism 34 Grinding wheel support device 37 Support column 38 Unloading arm moving mechanism 40 Temporary placement cassette 50 Illuminator 51 CCD camera X, Y Horizontal direction Z Height direction

Claims (10)

Wafer chamfering to chamfer the wafer to the target diameter and target peripheral end shape by contacting a grindstone with the peripheral end of the wafer placed and rotated on the rotary table. In the method
When starting chamfering of one lot consisting of a plurality of wafers, a first step of adopting one wafer in this lot as a sample wafer;
The position of the grindstone is set so that the sample wafer is processed into a sample diameter and a target peripheral edge shape larger than the target diameter by a predetermined dimension, and the sample wafer is subjected to trial processing. Steps,
A third step of measuring the diameter or peripheral edge shape of the sample wafer that has been trial-processed;
A fourth step of correcting the relative position of the grindstone with respect to the rotary table based on the measurement result of the sample wafer;
A fifth lot is sequentially processed into a target diameter and a target peripheral edge shape by using the grindstone at the corrected position for the sample wafer after trial processing and one or more other wafers in the lot. and the step, the possess,
In the third step, the wafer peripheral shape is measured at a plurality of locations at predetermined rotation angles on the circumference of the sample wafer,
The wafer chamfering method according to the fourth step, wherein the relative position of the grindstone with respect to the rotary table is corrected for each of the plurality of locations .   The sample wafer is compared with the diameter or peripheral end shape measured for the sample wafer in the third step and the sample diameter or target peripheral end shape set in the second step. After the fourth step and before the fifth step until the difference between the measured diameter or peripheral end shape and the sample diameter or the target peripheral end shape becomes smaller than a predetermined value. 2. The wafer chamfering method according to claim 1, wherein the steps from the first step to the fourth step are repeated using a wafer different from the sample wafer in the same lot as the sample wafer. Sixth step of measuring the diameter or peripheral shape of the lot-processed wafer after lot processing in one or more of the wafers to be lot-processed, and the relative position of the grindstone to the rotary table based on the measurement result A seventh step of correcting
The wafer chamfering method according to claim 1, wherein the wafer is chamfered.   4. The wafer chamfering method according to claim 3, wherein the sixth step to the seventh step are performed at intervals of a predetermined number of wafers to be lot processed.   In the method of chamfering a wafer using a plurality of turntables, the second to fourth steps are performed by adopting different wafers in the same lot as sample wafers for each of the turntables. The wafer chamfering method according to any one of claims 1 to 4. Wafer chamfering to chamfer the wafer to the target diameter and target peripheral end shape by contacting a grindstone with the peripheral end of the wafer placed and rotated on the rotary table. In the method
When starting chamfering of one lot consisting of a plurality of wafers, a first step of adopting one wafer in this lot as a sample wafer;
The position of the grindstone is set so that the sample wafer is processed into a sample diameter and a target peripheral edge shape larger than the target diameter by a predetermined dimension, and the sample wafer is subjected to trial processing. Steps,
A third step of measuring the diameter or peripheral edge shape of the sample wafer that has been trial-processed;
A fourth step of correcting the relative position of the grindstone with respect to the rotary table based on the measurement result of the sample wafer;
A fifth lot is sequentially processed into a target diameter and a target peripheral edge shape by using the grindstone at the corrected position for the sample wafer after trial processing and one or more other wafers in the lot. And having steps,
Above in the first step, chamfering method features and to roux Eha to adopt wafers of a predetermined number after the start of the lot as the sample wafer. A rotating table that rotates the wafer placed on the center,
A grindstone for chamfering the wafer in contact with the peripheral edge of the wafer placed on the turntable and rotated;
A chamfering device for a wafer having
A processing position adjusting device that adjusts the relative position of the grindstone and the wafer placed on the rotary table;
A measuring device for measuring the diameter and peripheral edge shape of the wafer;
At the start of processing of a new lot of wafers, one wafer in this lot is adopted as a sample wafer and placed on a rotary table, and the sample diameter is set by a predetermined dimension larger than the target diameter by the grinding wheel. Trial processing is performed to the same peripheral edge shape setting as the target peripheral edge shape, and the diameter or peripheral edge shape of the sample wafer subjected to the trial processing is measured by the measuring device, and the processing position is determined based on the measurement result. The relative position of the grindstone with respect to the rotary table is corrected by the adjusting device, and the target diameter is set to the sample wafer after the trial processing and one or more other wafers in the lot by the grindstone at the corrected position. In addition, the rotary table, the grindstone, and the processing position adjustment are performed so that the lot processing is sequentially performed to the target peripheral edge shape setting. A device and a processing control unit for controlling the measuring device,
A temporary storage device that takes out the sample wafer that has been trial processed from the rotary table and stores it until the lot processing,
A wafer chamfering device characterized by comprising: The said grindstone is two grindstones without a groove | channel which chamfers a wafer by simultaneously contacting the position close | similar to the same location of the peripheral edge part of the wafer mounted on the turntable and rotated. Item 8. The wafer chamfering device according to Item 7 . A roughing grindstone that chamfers the wafer roughly, and a fine grinding wheel that chamfers the wafer chamfered by the roughening grindstone,
8. The wafer chamfering apparatus according to claim 7 , wherein the processing control unit corrects the processing position of the grinding wheel for fine grinding based on the measurement result. 10. The wafer chamfering apparatus according to claim 9 , wherein the processing control unit also corrects the processing position of the roughing grindstone based on the measurement result.

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