JP5387887B2 - Chamfering method and chamfering apparatus - Google Patents

Description

  The present invention relates to a chamfering method and a chamfering apparatus for chamfering a wafer which is a material of a semiconductor device or an electronic component cut from a semiconductor ingot.

  A wafer such as silicon, which is a material for semiconductor devices and electronic components, is sliced from the ingot state with a slicing device such as an inner peripheral blade or a wire saw, and then the outer peripheral portion is prevented to prevent cracking or chipping of the peripheral edge. Chamfering is applied to The chamfering device used for chamfering is attached with a plurality of various grindstones such as a grindstone for grinding the outer circumference of the wafer and a notch grindstone for grinding a V-shaped notch serving as a reference position for the orientation, These grindstones are processed by rotating them at high speed with a spindle. At the time of processing, the wafer is sucked and mounted on a rotating wafer table, and the wafer and the grindstone are relatively moved by the guide shafts of the X guide, the Y guide, and the Z guide, and the chamfer formed on the grindstone is formed. Chamfering is performed by placing the outer periphery of the wafer against the groove for use.

  FIG. 1 shows a conventional example of a chamfering apparatus. FIG. 1 is a front view of a conventional chamfering apparatus. The chamfering apparatus 10 includes a wafer feeding unit 20, a grindstone rotating unit 50, a wafer supply / storage unit (not shown), a wafer cleaning / drying unit, a wafer transfer unit, and a controller that controls operations of each part of the chamfering device.

  The wafer feeding unit 20 includes an X-axis base 21, two X-axis guide rails 22, 22, four X-axis linear guides 23, 23,. It has an X table 24 that is moved in the X direction in the figure by the X axis driving means 25.

  The X table 24 is moved in the Y direction in the figure by Y axis driving means comprising two Y axis guide rails 26, 26, four Y axis linear guides 27, 27,..., A ball screw and a servo motor (not shown). A Y table 28 is incorporated.

  The Y table 28 is guided by two Z-axis guide rails 29 and 29 and four Z-axis linear guides (not shown), and is moved in the Z direction in the figure by a Z-axis driving means 30 comprising a ball screw and a stepping motor. Z table 31 is incorporated.

  The Z table 31 incorporates a θ-axis motor 32 and a θ spindle 33, and a wafer table 34 on which the wafer W is sucked and mounted is attached to the θ spindle 33. The wafer table 34 has a wafer table rotation axis CW. It is rotated in the θ direction in the figure as the center. The upper surface of the wafer table 34 is a suction surface that communicates with a vacuum source (not shown), and a wafer W to be chamfered or a truing grindstone (hereinafter referred to as a truer) for truing a grindstone to be chamfered is placed. And fixed by suction.

  By this wafer feeding unit 20, the wafer W and the truer are rotated in the θ direction in the figure and moved in the X, Y, and Z directions.

  The grindstone rotating unit 50 is provided with an outer peripheral grindstone 52 in which a plurality of outer peripheral rough grinding grooves are formed, and an outer grindstone spindle 51 and an outer peripheral grindstone 52 that are driven to rotate around an axis CH by an unillustrated outer grindstone motor. And a notch coarse spindle 60 and a notch coarse spindle 62, a notch fine spindle 57 and a notch fine motor 59.

  A peripheral grinding wheel 55 which is a chamfering grindstone for finish grinding the outer circumference of the wafer W is attached to the peripheral grinding spindle 54. A notch rough grinding wheel 61 is attached to the notch rough spindle 60, and a notch fine grinding wheel 58, which is a chamfering grind for finishing grinding the notch portion, is attached to the notch fine spindle 57.

  The outer peripheral fine grinding wheel 55, the notch rough grinding wheel 61, and the notch fine grinding wheel 58 are moved to the machining positions as the rotary 63 rotates.

  The outer peripheral grinding wheel 55 and the notch precision grinding wheel 58 are trued by the truer T mounted on the upper surface of the wafer table 34 or the truer T attached to the lower part of the wafer table to form the outer peripheral fine grinding groove. As such a chamfering apparatus, for example, a wafer chamfering apparatus described in Patent Document 1 has been proposed.

As described, a wafer as a material for a semiconductor device, an electronic component, or the like is manufactured by slicing a slicing device such as an inner peripheral blade or a wire saw from an ingot state, and chamfering the outer peripheral portion with various grindstones. At this time, processing is performed so that the upper and lower chamfer widths formed by the grinding grooves are equal or a predetermined chamfer width. In recent years, the design rules have been refined as the performance of semiconductor devices has improved, and the chamfers have been reduced. It is required that the variation in chamfering width due to processing be suppressed to a very small level. Factors that cause the chamfer width to vary include the flatness of the wafer table that holds and fixes the wafer, variations in wafer thickness, and warpage of the wafer.
JP 2005-153085 A

  However, when the wire comes out of the ingot at the end of the ingot cutting, the wire tension becomes unstable and the wire tends to fluctuate in the thickness direction of the wafer, causing variations in thickness and warping of the wafer. In addition, variations in thickness and warping that occur are different in tendency within the same lot. For these reasons, the chamfering width after chamfering is not constant, and there is a problem that variations occur.

  The present invention has been made in view of such a situation, and provides a chamfering method and a chamfering apparatus that realizes a highly accurate wafer chamfering width without being affected by variations in wafer thickness and warpage. It is aimed.

In order to achieve the above-mentioned object, the present invention is to place a wafer cut from a cylindrical semiconductor ingot on a wafer table, rotate it, and bring it into contact with a rotating grindstone having grooves formed in a desired shape. in chamfering method for chamfering an edge portion of the wafer, the thickness measuring step of the thickness of the end portion of the wafer was measured in the measuring unit transmits the data relating to the obtained the thickness to the control unit and the recording, the wafer the measured position of the thickness direction of the wafer at the end of the wafer by a position sensor provided in the vicinity of the wafer table in a state of being sucked and mounted on the wafer table, the data relating to the position of the obtained the thickness direction a warpage measuring step of transmitting and recording to said control unit, said by said warpage measuring step and said thickness measuring step From the data relating to said Thickness and the thickness direction position at the ends of the measured recorded the wafer before processing takes, calculated to record the relative position in each rotation angle of the said grindstone wafer by the control unit A position calculating step for calculating a relative position for each rotation angle based on the data extracted from the angle range including each rotation angle for each rotation angle in the chamfering process, and the position calculation step. Based on the relative position calculated and recorded before the chamfering process , the position of the wafer is adjusted while adjusting the position of the grindstone and the wafer in synchronization with the rotation of the wafer placed on the wafer table . And a chamfering method for chamfering the end portion .

  In the invention, the position sensor is any one of a laser sensor, a capacitance sensor, and an air microsensor.

Further, the present invention is relative and the wafer table for placing the Kwai Ha cut from cylindrical semiconductor ingot, and one or more of the grinding wheel for grinding an edge portion of the wafer, the wafer table relative to the grinding wheel moving means for moving the manner to measure the thickness of the end portion of the wafer, and a measuring unit for transmitting data relating to said measured thickness, the wafer at the end of the wafer placed on the wafer table the wafer position in the thickness direction were measured, and the position sensor provided in the vicinity of the wafer table to transmit data relating to the position of said measured thickness direction were measured and transmitted by said position sensor and said measuring portion of the wafer of recording data relating to said thickness and the thickness direction position at the end was measured before chamfering recording From the data relating to the position of the thickness and the thickness direction at the ends, together with the calculated relative position in each rotation angle of the grinding wheel and the wafer is recorded, and the grinding wheel on the basis of the relative position in the machining point and the wafer A control unit that adjusts the position of each of the rotation angles, and calculates a relative position for each rotation angle based on the data extracted from the angle range including each rotation angle for each rotation angle in the chamfering process, before the chamfering process Based on the calculated and recorded relative position, the position of the grindstone and the wafer is adjusted in synchronization with the rotation of the wafer placed on the wafer table with respect to the edge of the wafer. There is provided a chamfering apparatus characterized by comprising a control unit that performs chamfering.

  With such a chamfering apparatus, first, a thickness measurement process is performed in which the thickness of the entire circumference of the edge of the wafer is measured in the measurement unit. Data on the measured thickness is sent to the control unit and recorded. Subsequently, a warp measurement process is performed in which the wafer is transported from the measurement unit onto the wafer table and mounted on the wafer table, and the position of the wafer in the thickness direction of the entire wafer edge is measured by the position sensor. Data on the measured position in the thickness direction is sent to the control unit and recorded. Subsequently, data at each rotation angle is extracted from the data on the thickness and thickness position of the entire circumference of the wafer edge obtained by the thickness measurement process and the warp measurement process, and relative to each rotation angle of the grindstone and the wafer from the extracted data. A position calculation step of calculating and recording the target position by the control unit is performed. Subsequently, chamfering is performed while adjusting the position of the grindstone and the wafer at the processing point based on the relative position obtained in the position calculating step.

  As a result, the end of the wafer is always uniformly chamfered in contact with the grinding groove of the grindstone, and is uniformly chamfered around the entire circumference of the wafer, so that there is no variation in the chamfer width without being affected by variations in wafer thickness or warpage. Realize highly accurate chamfering.

  As described above, according to the chamfering method and the chamfering apparatus of the present invention, the thickness and position in the thickness direction at each rotation angle of the wafer end measured before processing are affected by variations in wafer thickness and warpage. Therefore, highly accurate wafer chamfering can be performed.

  Hereinafter, preferred embodiments of a chamfering method and a chamfering apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  First, a wafer chamfering apparatus according to the present invention will be described. FIG. 2 is a front view showing the main part of the chamfering device, and FIG. 3 is a top view showing the configuration of the chamfering device. The chamfering apparatus 1 includes a wafer feeding unit 2 and a grindstone rotating unit 50 as shown in FIG. 2, and further includes a measuring unit 3 and a wafer transfer means 4 as shown in FIG. In addition, the chamfering device 2 includes a wafer supply / storage unit, a wafer cleaning / drying unit, a control unit for controlling the operation of each part of the chamfering device, and the like (not shown).

  The wafer feeding unit 2 includes an X-axis base 21 mounted on the main body base 11, two X-axis guide rails 22, 22, four X-axis linear guides 23, 23,..., A ball screw, and a stepping motor. It has an X table 24 that is moved in the X direction in the figure by the X axis driving means 25.

  The X table 24 is moved in the Y direction in the figure by Y axis driving means comprising two Y axis guide rails 26, 26, four Y axis linear guides 27, 27,..., A ball screw and a stepping motor (not shown). A Y table 28 is incorporated.

  The Y table 28 is guided by two Z-axis guide rails 29 and 29 and four Z-axis linear guides (not shown), and is moved in the Z direction in the figure by a Z-axis driving means 30 comprising a ball screw and a stepping motor. Z table 31 is incorporated.

  The Z table 31 incorporates a θ-axis motor 32 and a θ spindle 33, and a wafer table (mounting table) 34 on which the wafer W is sucked and mounted is attached to the θ spindle 33, and the wafer table 34 rotates the wafer table. It is rotated around the axis CW in the θ direction in the figure.

  The upper surface of the wafer table 34 is a suction surface that communicates with a vacuum source (not shown), and a truing grindstone used for truing a grindstone for chamfering a wafer W or a chamfering finish is placed on and fixed by suction. Is done.

  In the vicinity of the upper part of the wafer table 34, a position sensor 5 for measuring the position in the thickness direction of the wafer W around the end of the wafer W mounted on the wafer table 34 (position in the Z direction shown in FIG. 2) is provided. It has been. The position sensor 5 is a sensor that detects positional fluctuations such as a laser sensor, a capacitance sensor, an air microsensor, etc., and the position in the Z direction of the entire circumference of the wafer W end is measured by rotating the wafer table 34. It is measured. Data on the measured position in the Z direction is transmitted to the control unit.

  Further, the position sensor 5 is protected from grinding water or the like which is covered with a cover 6 and scatters during chamfering. Further, an air nozzle 7 is provided in the vicinity of the cover 6 and upstream of the position sensor 5 in the wafer W rotation direction. The air nozzle 7 ejects air toward the surface of the wafer W to remove grinding water or the like on the surface of the wafer W and facilitate measurement by the position sensor 5. Although one position sensor 5 is provided on the wafer table 34, it may be provided vertically so as to sandwich the wafer W therebetween.

  By this wafer feeding unit 2, the wafer W and the truer are rotated in the θ direction in the figure and moved in the X, Y, and Z directions. Further, the position in the Z direction of the end portion of the wafer W can be measured in a state where the position sensor 5 is sucked and placed on the wafer table 34.

  The grindstone rotating unit 50 is provided with an outer peripheral grindstone 52 in which a plurality of outer peripheral rough grinding grooves are formed, and an outer grindstone spindle 51 and an outer peripheral grindstone 52 that are driven to rotate around an axis CH by an unillustrated outer grindstone motor. And a notch coarse spindle 60 and a notch coarse spindle 62, a notch fine spindle 57 and a notch fine motor 59.

  A peripheral grinding wheel 55 which is a chamfering grindstone for finish grinding the outer circumference of the wafer W is attached to the peripheral grinding spindle 54. A notch rough grinding wheel 61 is attached to the notch rough spindle 60, and a notch fine grinding wheel 58, which is a chamfering grind for finishing grinding the notch portion, is attached to the notch fine spindle 57.

  The peripheral processing grindstone 52 is a diamond-bonded metal bond grindstone having a particle size # 800. The peripheral grinding wheel 55 is a resin bond grindstone of diamond abrasive grains having a diameter of 50 mm, and has a grain size of # 3000. Further, the notch rough grinding wheel 61 has a small diameter of 1.8 mm to 2.4 mm, a diamond bond metal bond grindstone, grain size # 800, and the notch fine grinding wheel 58 has a diameter of 1.8 mm to 2.4 mm. A resin bond grindstone of diamond abrasive grains, grain size # 4000 is used.

  The outer peripheral grinding wheel spindle 51 is a built-in motor driven spindle using a ball bearing and is rotated at a rotational speed of 8,000 rpm. Further, the outer peripheral precision spindle 54 is a built-in motor driven spindle using an air bearing and is rotated at a rotational speed of 35,000 rpm.

  The notch rough spindle 60 is an air turbine driven spindle using an air bearing and is rotated at a rotational speed of 80,000 rpm. The notch precision spindle 57 is a built-in motor driven spindle using an air bearing and has a rotational speed of 150, Rotated at 000 rpm.

  As shown in FIG. 3, the measurement unit 3 includes a table 9 for placing and rotating the wafer W sucked and transferred by the arm 8 of the wafer transfer means 4 from the wafer supply / storage unit. Measure the thickness of the entire circumference. The thickness sensors 12 are sensors that detect positional fluctuations such as a laser sensor, a capacitance sensor, and an air microsensor. The two thickness sensors 12 are arranged so as to sandwich the edge of the wafer W, thereby measuring the thickness of the edge of the wafer W. To do. Data on the measured thickness is transmitted to the control unit.

  Since the other components of the chamfering apparatus 1 are generally well-known mechanisms, detailed description will be omitted.

  Next, the chamfering method according to the present invention will be described. FIG. 4 is a system configuration diagram in which the chamfering method is performed, and FIG. 5 is a flowchart showing the procedure of the chamfering method.

  In the chamfering method, first, the wafer W transferred from the wafer supply / storage unit is transferred to the table 9 by the wafer transfer means 4 shown in FIG. After the suction placement, the thickness of the entire circumference of the edge of the wafer W is measured by the thickness sensor 12 (thickness measurement step S1 shown in FIG. 5).

  Data relating to the thickness of the edge of the wafer W measured by the thickness sensor 12 is sent to and recorded in the arithmetic recording means 15 via the sensor controller 14 provided in the control unit 13 shown in FIG.

  Subsequently, the wafer W is transferred from the table 9 to the wafer table 34 and placed on the wafer. The position of the wafer placed on the wafer table 34 by suction is measured by the position sensor 5 in the Z direction along the entire circumference of the end (warp measurement step S2 shown in FIG. 5).

  Data relating to the position in the Z direction of the edge of the wafer W measured by the position sensor 5 is sent to the operation recording means 15 via the sensor controller 14 provided in the control unit 13 and recorded.

  Subsequently, from the data regarding the thickness of the entire circumference of the wafer W end portion recorded in the calculation recording means 15 and the position in the Z direction at each rotation angle of the wafer W end portion in a state of being sucked and mounted on the wafer table 34, The relative position of each grindstone provided in the chamfering processing apparatus 1 and the wafer W at each rotation angle is calculated and recorded by the operation recording means 15 (position calculation step S3 shown in FIG. 5).

  In the position calculation step S3, first, data relating to the thickness of the entire circumference of the edge of the wafer W and the position in the Z direction is filtered. After the filtering process, data at each rotation angle that matches the surface width measurement position after the chamfering process at the edge of the wafer W is extracted from the data. By processing the extracted data by the operation recording means 15, the relative position of each grindstone and wafer W at each rotation angle is calculated. In the extraction of data at each rotation angle, data having a maximum value is extracted in a predetermined angle range at each rotation angle position.

  Subsequently, the position of the wafer W in the X, Y, and Z directions is adjusted to the relative position at the processing point by controlling the wafer feeding unit 2 via the chamfering controller 16 based on the calculated and recorded relative position. The chamfering process is performed on the edge of the wafer W (processing step S4 shown in FIG. 5).

  The wafer W processed by adjusting the position based on the relative position as described above is compared with the variation in the surface width at each rotation angle in FIG. Chamfering with very little variation is possible.

  As described above, according to the chamfering processing method and the chamfering processing apparatus according to the present invention, each grindstone and each of the wafers are based on the thickness and the thickness direction position at each rotation angle of the wafer end measured before processing. A relative position at the rotation angle is calculated. By performing chamfering while adjusting the position of the wafer based on the calculated relative position, wafer chamfering with high accuracy is possible without being affected by variations in wafer thickness and warpage.

The front view which shows the principal part of the conventional wafer chamfering processing apparatus. The front view which shows the principal part of the chamfering processing apparatus concerning this invention. The top view which showed the structure of the chamfering processing apparatus concerning this invention. The system block diagram by which the chamfering method is performed. The flowchart which showed the procedure of the chamfering method. The chart which compared the processing result by the conventional chamfering method, and the processing result by the chamfering method of this invention.

  DESCRIPTION OF SYMBOLS 1, 10 ... Chamfering apparatus, 2, 20 ... Wafer feeding unit, 3 ... Measuring part, 4 ... Wafer conveyance means, 5 ... Position sensor, 6 ... Cover, 7 ... Air nozzle, 8 ... Arm, 9 ... Table, 12 ... Thickness Sensor, 13 ... Control unit, 14 ... Sensor controller, 15 ... Calculation and recording means, 16 ... Chamfering machine controller, 24 ... X table, 28 ... Y table, 33 ... θ spindle, 34 ... Wafer table, 52 ... Wheel grinding wheel, 54 ... Peripheral Precision Spindle, 55 ... Peripheral Precision Grinding Wheel (Chamfering Grinding Wheel), 55a ... Peripheral Groove, 55b ... Orientation Flat Groove, 58 ... Notch Fine Grinding Wheel, 61 ... Notch Coarse Grinding Wheel, W ... Wafer

Claims (3)

A chamfering process that chamfers the edge of the wafer by placing the wafer cut from the cylindrical semiconductor ingot on a wafer table, rotating it, and contacting a rotating grindstone with grooves formed in a desired shape. In the method
The thickness measuring step of the thickness of the end portion of the wafer was measured in the measuring unit transmits the data relating to the obtained the thickness to the control unit and recording,
The wafer by a position sensor provided on the table near to measure the position in the thickness direction of the wafer at the end of the wafer, the position of the resulting the thickness direction in a state in which adsorbed placing the wafer on the wafer table A warpage measuring step for transmitting and recording data relating to the control unit;
From the data relating to said Thickness and the thickness direction position at the end of the by the the thickness measuring step the warpage measuring step is measured before the chamfering recorded the wafer, in each rotation angle of the said grindstone wafer A position calculation step of calculating and recording a relative position by the control unit, wherein the relative position for each rotation angle is determined based on the data extracted from the angle range including each rotation angle for each rotation angle in the chamfering process. A position calculating step to calculate ;
Based on the relative position calculated and recorded before the chamfering process in the position calculating step , the position of the grindstone and the wafer is adjusted in synchronization with the rotation of the wafer placed on the wafer table. While processing the chamfering on the edge of the wafer ,
A chamfering method characterized by comprising :   The chamfering method according to claim 1, wherein the position sensor is any one of a laser sensor, a capacitance sensor, and an air microsensor. A wafer table for placing a wafer cut from a cylindrical semiconductor ingot;
One or more grindstones for grinding the edge of the wafer;
Moving means for moving the wafer table relative to the grindstone;
Measuring the thickness of the end portion of the wafer, and a measuring unit for transmitting data relating to said measured thickness,
A position sensor provided in the vicinity of the wafer table for measuring a position in the thickness direction of the wafer at an end portion of the wafer placed on the wafer table and transmitting data on the measured position in the thickness direction; ,
At the end of the measuring unit and records data related to the measurement and transmitted said Thickness and the thickness direction position at the end of the wafer by said position sensor, the wafer recorded measured before chamfering From the data on the thickness and the position in the thickness direction, the relative position at each rotation angle of the grindstone and the wafer is calculated and recorded, and the position of the grindstone and the wafer is determined based on the relative position at the processing point. A control unit for adjusting , calculating a relative position for each rotation angle based on the data extracted from an angle range including each rotation angle for each rotation angle in the chamfering process, and calculating and recording before the chamfering process. The grindstone is synchronized with the rotation of the wafer placed on the wafer table based on the relative position. And a control unit for performing the chamfering to an end of the wafer while adjusting the position of said wafer,
A chamfering apparatus characterized by comprising:

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