JP6872374B2 - Piezoelectric wafer front / back judgment device and chamfering device - Google Patents

Description

The present invention relates to a front-back determination device for determining the front and back sides of a piezoelectric wafer, and a chamfering device incorporating a front-back determination device for chamfering the outer periphery of a piezoelectric wafer.

Conventionally, there are wafers made of semiconductor device materials such as lithium niobate (LiNbO ₃ ) and lithium tantalate (LiTaO _{3) as oxide crystals.} These wafers have a pyroelectric effect that depends on the crystal orientation. Therefore, it is necessary to determine the front and back sides according to the polarization direction of the crystal. However, since this polarization direction is determined by the polling process, the front and back cannot be determined only by the crystal orientation. This is because even if the z-axis direction of the crystal orientation is clarified, the + z direction and the −z direction determined by the polling process are still unknown. Further, these wafers have almost the same appearance on the front and back sides. Therefore, even if the orientation flat exists, it may not be possible to visually determine the front and back sides.

As a technique for determining the front and back of a wafer, for example, a method of determining the front and back of a wafer based on the position of a sub-orientation flat is known (see, for example, Patent Document 1). In this method, a plurality of points along the contour of the wafer are extracted from the image obtained by imaging the outer edge of the wafer to perform linear approximation, and it is determined whether or not the outer edge is a linear sub-orientation flat. To do. However, in this method, apart from the main orientation flat, it is necessary to form a special linear sub-orientation flat for determining the front and back sides on the wafer.

Further, as another technique for determining the front and back surfaces of a wafer, a method of forming a void as a mark inside the wafer by using a laser beam is known (see, for example, Patent Document 2).

Further, as yet another technique for determining the front and back surfaces of a wafer, a method is known in which the difference between the reflectance of the front surface and the reflectance of the back surface when the front surface and the back surface of the wafer are irradiated with laser light is used (for example). , Patent Document 3).

Further, as another technique for determining the front and back of the wafer, a method of sandwiching the wafer with a polarizing plate and visually observing the direction of pulse (see, for example, Patent Document 4) and a method of using X-ray diffraction are used. (See, for example, Patent Document 5 and Patent Document 6) are known. Further, when both sides of the wafer subjected to the backside damage treatment are irradiated with visible light, the intensity of the blue wavelength component of the scattered light by the back surface of the wafer is higher than that by the front surface of the wafer (for example,). (See Patent Document 7) is also known. Further, a method of forming a fine groove as a mark on the front surface or the back surface of the wafer (see, for example, Patent Documents 8 and 9), and a method of utilizing the photoelectric effect of the thin film semiconductor formed only on the front surface of the wafer. (See, for example, Patent Document 10), a method utilizing the difference between the warp shape on the front surface and the warp shape on the back surface after double-sided polishing (see, for example, Patent Document 11), and the shape of the mesa on the front surface of the wafer. A method of utilizing the difference in reflected light intensity due to the difference between the shape of the wafer and the shape of the wafer on the back surface (see, for example, Patent Document 12) is also known.

However, the methods described in Patent Documents 1 to 12 cannot determine the polarization direction of the crystal, and cannot determine the front and back sides of the wafer according to the polarization direction of the crystals constituting the wafer.

As an apparatus for determining the front and back surfaces depending on the polarization direction of the wafer, the crystal polarity determining apparatus described in Patent Document 13 is known.

This crystal polarity determining device determines the front and back sides based on the voltage waveform due to the piezoelectric effect of the wafer generated when the wafer is vibrated at the end surface (peripheral surface) of the disk-shaped wafer. Specifically, the front and back are determined based on the phase difference between the vibration waveform and the voltage waveform.

Japanese Unexamined Patent Publication No. 2004-356411 Patent No. 4569097 Japanese Unexamined Patent Publication No. 63-110651 Japanese Unexamined Patent Publication No. 3-173148 Japanese Unexamined Patent Publication No. 2005-77271 Patent No. 2770232 Japanese Unexamined Patent Publication No. 2010-251542 Japanese Unexamined Patent Publication No. 62-260106 Jikkai Sho 62-73532 Japanese Unexamined Patent Publication No. 11-281309 Japanese Unexamined Patent Publication No. 2001-156152 Japanese Unexamined Patent Publication No. 2006-156895 Japanese Unexamined Patent Publication No. 2014-224693

However, since the device of Patent Document 13 applies vibration at the end face of the wafer, the configuration of the mechanism for applying vibration becomes complicated. In addition, it is necessary to perform a complicated operation of deriving the phase difference between the vibration waveform and the voltage waveform.

In view of the above points, it is desirable to provide a front / back determination device for determining the front / back of a wafer with a simpler configuration and a simpler calculation.

In order to achieve the above object, the front / back determination device according to the embodiment of the present invention is a front / back determination device for determining the front / back of the piezoelectric wafer, and is a front / back determination device from any one direction of the front / back of the piezoelectric wafer. A voltage applying portion configured to be able to apply a striking force to a predetermined position on any one surface, and a voltage generated in the piezoelectric wafer according to the striking force applied by the striking force applying portion. a voltage detection unit for detecting, have a, and front and back determining unit determines the front and back of the piezoelectric wafer on the basis of the pulse waveform of the voltage detected by the voltage detecting unit, wherein the predetermined position, the piezoelectric wafer It is a position between the center and the outer edge of the piezoelectric wafer .

By the above means, it is possible to provide a front / back determination device for determining the front / back of a wafer with a simpler configuration and a simpler calculation.

It is a functional block diagram which shows the structural example of the front-back determination apparatus which concerns on embodiment of this invention. It is the schematic of the front-back determination device of FIG. It is sectional drawing of the upper expansion and contraction mechanism. It is sectional drawing of the lower expansion and contraction mechanism. It is a top view of the front-back determination device when the orientation flat detection device detects the orientation flat. It is a figure which shows the time transition of the voltage generated by the piezoelectric effect. It is a flowchart of the front-back determination process. It is a functional block diagram of a beveling device. It is the schematic of the beveling apparatus of FIG. It is a functional block diagram of a beveling device. It is a flowchart of the front-back determination process executed by the beveling apparatus of FIG. It is a plan view of the beveling device.

FIG. 1 is a functional block diagram showing a configuration example of a front / back determination device 100 according to an embodiment of the present invention. Further, FIG. 2 is a schematic view of the front / back determination device 100. In this embodiment, the front / back determination device 100 determines, for example, the front / back of the wafer W determined according to the polarization direction of the piezoelectric wafer (hereinafter, referred to as “wafer W”) having a pyroelectric effect depending on the crystal orientation. To do.

The wafer W is formed of an oxide crystal having a piezoelectric effect such as _{lithium niobate (LiNbO 3} ) and lithium tantalate (LiTaO _3). The polarization direction of the wafer W (strictly, it means the + z direction) is determined by the polling process. The polarization direction of the wafer W may normally be inclined with respect to the disk surface of the wafer W and have a vertical component, but in the following, for convenience of explanation, the vertical component is not considered. .. The front and back surfaces of the wafer W are reproducibly determined according to arbitrary determination conditions, and are not absolute.

In this embodiment, the front / back determination device 100 mainly includes a control device 1, an impact force applying device 2, a voltage detecting device 3, and an output device 4.

The control device 1 is an example of a control means for controlling the front / back determination device 100, and is, for example, a computer provided with a CPU, a volatile storage medium, a non-volatile storage medium, an input / output interface, and the like. Specifically, the control device 1 reads, for example, a program corresponding to each functional element of the impact force applying unit 10, the voltage detecting unit 11, and the front and back determination unit 12 from the non-volatile storage medium and turns it into a volatile storage medium. It is expanded and the CPU is made to execute the process corresponding to each functional element.

The striking force applying device 2 is an example of a striking force applying means for applying a striking force to the disk surface of the wafer W, and is mainly an upper electrode 2aU, an upper expansion / contraction mechanism 2bU, an upper insulator 2cU, and a lower electrode. Includes 2aD, lower telescopic mechanism 2bD, lower insulator 2cD, support unit 2d, stage 2e, rotating shaft 2f, rotating mechanism 2g, support base 2h, and the like.

The upper electrode 2aU is an electrode that contacts the upper surface of the wafer W placed on the stage 2e, and the lower electrode 2aD is an electrode that contacts the lower surface of the wafer W. In the example of FIG. 2, the pair of electrodes, the upper electrode 2aU and the lower electrode 2aD, constitute a member for extracting a voltage generated by the piezoelectric effect of the wafer W. In the example of FIG. 2, the upper electrode 2aU and the lower electrode 2aD are formed of conductive rubber. This is to stabilize the contact with the wafer W so that the voltage generated by the piezoelectric effect of the wafer W can be stably detected. However, the upper electrode 2aU and the lower electrode 2aD may be made of metal.

The upper expansion / contraction mechanism 2bU is a mechanism that brings the upper electrode 2aU into contact with the upper surface of the wafer W, and constitutes a force applying mechanism that applies a force to the upper surface of the wafer W. In the example of FIG. 2, the upper expansion / contraction mechanism 2bU is composed of an air cylinder, and the upper electrode 2aU is attached to the lower end of the rod that the air cylinder expands / contracts.

The upper expansion / contraction mechanism 2bU extends the rod downward in response to a control signal from the control device 1 to bring the upper electrode 2aU attached to the lower end of the rod into contact with the upper surface of the wafer W.

Further, the upper expansion / contraction mechanism 2bU presses the upper electrode 2aU against the upper surface of the wafer W for a predetermined time, and then retracts the rod upward to pull the upper electrode 2aU away from the upper surface of the wafer W.

The upper electrode 2aU may be attached to the lower end of the rod via a compression spring. This is to prevent the impact force applied to the upper surface of the wafer W by the upper electrode 2aU from becoming excessively large. Specifically, when the force exerted by the upper expansion / contraction mechanism 2bU on the wafer W exceeds a predetermined value, the compression spring absorbs the force by retracting the upper electrode 2aU vertically upward to break the wafer W. To prevent.

FIG. 3 shows another configuration example of the upper expansion / contraction mechanism 2bU. FIG. 3 is a cross-sectional view of the upper expansion / contraction mechanism 2bU. The upper expansion / contraction mechanism 2bU of FIG. 3 is mainly composed of a striking portion 20a, an elastic member 20b, an electric actuator 20c, and a housing 20d. The electric actuator 20c is driven in response to a control signal from the control device 1 to move the striking portion 20a and the elastic member 20b up and down. The electric actuator 20c can strike the upper electrode 2aU attached to the tip of the striking portion 20a against the upper surface of the wafer W at a speed specified by the control signal. The electric actuator 20c raises the upper electrode 2aU after pressing the upper electrode 2aU against the wafer W for a predetermined pressing time in a state where the upper electrode 2aU is in contact with the wafer W. The pressing time is, for example, several tens of microseconds to several hundred milliseconds.

The elastic member 20b is elastically deformed when the striking portion 20a continues to descend even after the upper electrode 2aU abuts on the wafer W. Therefore, it is possible to prevent a force higher than the elastic pressure (spring pressure) from acting on the wafer W. The elastic member 20b is composed of, for example, a string-wound spring, a rubber body, or the like. The elastic pressure (spring pressure) is, for example, 50 g to 300 g.

The striking portion 20a has a shape in which the upper electrode 2aU attached to the tip end can give an impact force to the upper surface of the wafer W. For example, the striking portion 20a has a cylindrical shape with a flat tip portion.

The lower expansion / contraction mechanism 2bD is a mechanism that brings the lower electrode 2aD into contact with the lower surface of the wafer W, and constitutes a support mechanism that supports the lower surface of the wafer W when applying an impact force to the upper surface of the wafer W. In the example of FIG. 2, the lower expansion / contraction mechanism 2bD is composed of an air cylinder like the upper expansion / contraction mechanism 2bU, and the lower electrode 2aD is attached to the upper end of the rod that the air cylinder expands and contracts.

The lower expansion / contraction mechanism 2bD extends the rod upward in response to a control signal from the control device 1 to bring the lower electrode 2aD attached to the upper end of the rod into contact with the lower surface of the wafer W.

Further, the lower expansion / contraction mechanism 2bD typically brings the lower electrode 2aD into contact with the lower surface of the wafer W before the upper electrode 2aU contacts the upper surface of the wafer W. However, the lower electrode 2aD may be brought into contact with the lower surface of the wafer W at the same time as the upper electrode 2aU is brought into contact with the upper surface of the wafer W. The lower electrode 2aD is arranged so as to face the upper electrode 2aU with the wafer W interposed therebetween. Then, when the upper electrode 2aU comes into contact with the upper surface of the wafer W, the wafer W is arranged so that the wafer W can be sandwiched between the upper electrode 2aU and the lower electrode 2aD. With this configuration, the impact force applying device 2 can apply a downward impact force to the upper surface of the wafer W.

FIG. 4 shows another configuration example of the lower expansion / contraction mechanism 2bD. FIG. 4 is a cross-sectional view of the lower expansion / contraction mechanism 2bD. The lower expansion / contraction mechanism 2bD of FIG. 4 is mainly composed of a support portion 22a, an electric actuator 22b, and a housing 22c. The electric actuator 22b is driven in response to a control signal from the control device 1 to move the support portion 22a up and down. The electric actuator 22b can bring the lower electrode 2aD attached to the tip of the support portion 22a into contact with the lower surface of the wafer W at a speed specified by the control signal. The support portion 22a has a shape in which the lower electrode 2aD attached to the tip end can support the lower surface of the wafer W. For example, the support portion 22a has a cylindrical shape with a flat tip portion.

The contact between the upper surface of the wafer W and the upper electrode 2aU and the contact between the lower surface of the wafer W and the lower electrode 2aD are both formed to be surface contact. In this case, the contact area is configured to be large enough to prevent the wafer W from cracking. Further, the contact surface (lower contact surface) between the lower surface of the wafer W and the lower electrode 2aD is configured to be larger than the contact surface (upper contact surface) between the upper surface of the wafer W and the upper electrode 2aU. Will be done. The upper contact surface and the lower contact surface are preferably flat surfaces. For example, the upper contact surface is a circular plane with a diameter of 5 mm and the lower contact surface is a circular plane with a diameter of 10 mm. However, the area of the upper contact surface may be equal to or larger than the area of the lower contact surface. The upper electrode 2aU and the lower electrode 2aD preferably have a disk shape, but may have a spherical shape, a hemispherical shape, a prismatic shape, or the like.

The support unit 2d is a member that supports the upper expansion / contraction mechanism 2bU and the lower expansion / contraction mechanism 2bD. In the example of FIG. 2, the upper telescopic mechanism 2bU is attached to the support unit 2d via the upper insulator 2cU, and the lower telescopic mechanism 2bD is attached to the support unit 2d via the lower insulator 2cD. Therefore, the upper telescopic mechanism 2bU is electrically insulated from the support unit 2d by the upper insulator 2cU, and the lower telescopic mechanism 2bD is electrically insulated from the support unit 2d by the lower insulator 2cD. The upper insulator 2cU and the lower insulator 2cD are formed of, for example, an insulator such as vinyl chloride.

The upper expansion / contraction mechanism 2bU may be attached to the support unit 2d so that the angle formed by the circular plane of the upper electrode 2aU and the upper surface of the wafer W can be adjusted. Similarly, the lower expansion / contraction mechanism 2bD may be attached to the support unit 2d so that the angle formed by the circular plane of the lower electrode 2aD and the lower surface of the wafer W can be adjusted. The circular plane of the upper electrode 2aU and the upper surface of the wafer W are parallel, the circular plane of the lower electrode 2aD and the lower surface of the wafer W are parallel, and the circular plane of the upper electrode 2aU and the circular plane of the lower electrode 2aD This is to make them parallel.

The stage 2e is a member that supports the wafer W. In the example of FIG. 2, the stage 2e is a vacuum suction stage formed of an insulator, and the vacuum suction is turned on / off according to a control signal from the control device 1.

The rotation mechanism 2g is a mechanism for rotating the stage 2e. In the example of FIG. 2, the rotation mechanism 2g is an electric motor, and is rotationally driven in response to a control signal from the control device 1. Then, the stage 2e attached to the upper end of the rotating shaft 2f extending in the vertical direction is rotated around the vertical shaft.

The rotation shaft 2f is a rod-shaped member that is rotationally driven by the rotation mechanism 2g. In the example of FIG. 2, it is a rotating shaft of an electric motor as a rotating mechanism 2g. The support base 2h is a member that rotatably supports the stage 2e and the rotation shaft 2f.

The voltage detecting device 3 is an example of a voltage detecting means for detecting a voltage generated by the piezoelectric effect of the wafer W. In the example of FIG. 2, the voltage detection device 3 is an oscilloscope, and detects the voltage generated by the piezoelectric effect of the wafer W through the upper electrode 2aU and the lower electrode 2aD. The voltage is the potential difference between the upper electrode 2aU and the lower electrode 2aD, and the wafer W is compressed in the vertical direction by the pressure (attack force) when the upper electrode 2aU contacts (collides) with the upper surface of the wafer W. Occurs in. Further, the voltage is generated by the wafer W extending in the vertical direction when the upper electrode 2aU is separated from the upper surface of the wafer W. Both the upper electrode 2aU and the lower electrode 2aD are connected to the oscilloscope via a conductive wire such as a coaxial analog cable. The coaxial analog cable may be in a floating state, for example.

The voltage detection device 3 records the change in voltage over a predetermined time as detection data, and outputs the recorded detection data to the control device 1. The voltage detection device 3 may output a change in voltage to the control device 1 in real time. The voltage detection device 3 may convert a voltage from an analog value to a digital value using an analog / digital converter or the like and output the voltage to the control device 1.

The output device 4 is a device for outputting various information, for example, a display for displaying the determination results of the front and back surfaces of the wafer by the control device 1, a speaker for outputting the determination results by voice, and the like. ..

The front / back determination device 100 may include an orientation flat detection device 7 that detects the orientation flat. The orientation flat detection device 7 detects the central portion of the orientation flat of the wafer W with a laser beam, for example, and outputs the detection signal to the control device 1. The orientation flat detection device 7 may be an image sensor. FIG. 5 is a top view of the front / back determination device 100 when the orientation flat detection device 7 detects the central portion of the orientation flat of the wafer W. For example, the control device 1 outputs a control signal to the rotation mechanism 2g to rotate the stage 2e. Then, the rotation angle of the rotation mechanism 2g (that is, the rotation angle of the wafer W) when the detection signal is received from the orientation flat detection device 7 is stored as a reference rotation angle. With this configuration, the control device 1 can rotate the wafer W placed on the stage 2e to a desired relative rotation angle with respect to the reference rotation angle.

Next, various functional elements included in the control device 1 will be described.

The striking force applying unit 10 is a functional element for operating the striking force applying means. In the example of FIG. 2, the striking force applying unit 10 outputs a control signal to the striking force applying device 2 to operate the striking force applying device 2.

Specifically, the impact force applying unit 10 outputs a control signal to the stage 2e and vacuum-sucks the wafer W placed on the stage 2e. After that, the impact force applying unit 10 may output a control signal to the rotation mechanism 2g and rotate the stage 2e so that the orientation flat of the wafer W comes to a predetermined position. At this time, the vacuum suction of the stage 2e may be turned off. After that, the impact force applying unit 10 outputs a control signal to the lower expansion / contraction mechanism 2bD, extends the rod of the air cylinder upward, and brings the lower electrode 2aD attached to the upper end of the rod into contact with the lower surface of the wafer W. After that, the impact force applying unit 10 outputs a control signal to the upper expansion / contraction mechanism 2bU, extends the rod of the air cylinder downward at a predetermined speed, and contacts the upper electrode 2aU attached to the lower end of the rod with the upper surface of the wafer W. Let me. When a predetermined time elapses after the upper electrode 2aU starts descending, the impact force applying unit 10 outputs a control signal to the upper expansion / contraction mechanism 2bU, retracts the rod of the air cylinder upward, and moves the upper electrode 2aU to the wafer W. Pull away from the top surface. In this way, the striking force applying unit 10 makes the striking force applied to the upper surface of the wafer W over a predetermined time.

The voltage detection unit 11 is a functional element for detecting the voltage (generated voltage) generated by the piezoelectric effect of the wafer W. In the example of FIG. 2, the voltage detection unit 11 acquires information on the pulsed generated voltage detected by the voltage detection device 3 from the voltage detection device 3. The voltage detection unit 11 may have an oscillograph function for directly detecting the generated voltage. In this case, the voltage detection device 3 may be omitted.

Specifically, the voltage detection unit 11 provides information on the generated voltage generated as a result of the impact force applying device 2 operating in response to the control signal output by the impact force applying unit 10 to apply the impact force to the upper surface of the wafer W. Is acquired, and the information is output to the front / back determination unit 12. The voltage detection unit 11 starts detecting the generated voltage when, for example, the impact force applying unit 10 starts lowering the upper electrode 2aU, and then, for a predetermined time (for example, 2 seconds), a predetermined interval (for example, 10 microsecond interval) ) Detects the repeatedly generated voltage. The voltage detection unit 11 may start detecting the generated voltage before the impact force applying unit 10 starts the lowering of the upper electrode 2aU.

The front / back determination unit 12 is a functional element for determining the front / back of the disk surface of the wafer W. In the example of FIG. 2, the front / back determination unit 12 determines the front / back of the disk surface of the wafer W, which depends on the polarization direction of the wafer W. The front / back determination unit 12 may determine the polarity (polarization direction) of the wafer W. In this case, the determination of the front and back surfaces of the disk surface of the wafer W in the following description may be replaced by the determination of the polarity (polarization direction) of the wafer W.

Specifically, the front / back determination unit 12 determines the front / back of the disk surface of the wafer W based on the positive / negative (polarity) of the generated voltage. For example, the front / back determination unit 12 determines that the upper surface is the surface when the voltage generated when the upper electrode 2aU is brought into contact with the upper surface of the wafer W is a positive value. Alternatively, the front / back determination unit 12 may determine that the upper surface is the surface when the voltage generated when the upper electrode 2aU is pulled away from the upper surface of the wafer W is a negative value. Alternatively, in the front / back determination unit 12, the voltage generated when the upper electrode 2aU is brought into contact with the upper surface of the wafer W is a positive value, and the voltage generated when the upper electrode 2aU is pulled away from the upper surface of the wafer W is a negative value. In some cases, it may be determined that the upper surface is the surface.

Similarly, the front / back determination unit 12 determines that the upper surface is the back surface when the voltage generated when the upper electrode 2aU is brought into contact with the upper surface of the wafer W is a negative value. Alternatively, the front / back determination unit 12 may determine that the upper surface is the back surface when the voltage generated when the upper electrode 2aU is pulled away from the upper surface of the wafer W is a positive value. Alternatively, in the front / back determination unit 12, the voltage generated when the upper electrode 2aU is brought into contact with the upper surface of the wafer W is a negative value, and the voltage generated when the upper electrode 2aU is pulled away from the upper surface of the wafer W is a positive value. In some cases, it may be determined that the upper surface is the back surface.

The front / back determination unit 12 outputs an alarm when it is determined that the front / back arrangement of the wafer W is not the desired front / back arrangement. The desired front-back arrangement refers to, for example, the case where the upper surface of the wafer W placed on the stage 5a is the front surface. When the front / back determination unit 12 determines, for example, that the upper surface of the wafer W is the back surface, the front / back determination unit 12 outputs a control signal to the output device 4, displays a text message notifying the fact on the display, or a voice notifying the fact. Output a message from the speaker.

The front / back determination unit 12 may output an alarm when the front / back arrangement of the wafer W cannot be determined. For example, the front / back determination unit 12 outputs a control signal to the output device 4 when the absolute value of the generated voltage when the upper electrode 2aU is brought into contact with the upper surface of the wafer W is less than a preset threshold value. Then, a text message indicating that the front and back arrangement of the wafer W cannot be determined is displayed on the display, or a voice message notifying the fact is output from the speaker.

In this way, when the front / back determination unit 12 detects an error state including a state in which the front / back arrangement of the wafer W is not the desired front / back arrangement, a state in which the front / back arrangement of the wafer W cannot be determined, and the like, the content of the error state is detected through the output device 4. Outputs a warning to inform you. Further, when the front / back determination unit 12 detects an error state, the front / back determination unit 12 may output a control signal to the stage 2e to turn off the vacuum suction of the wafer W. This is so that the wafer W can be removed.

Next, with reference to FIG. 6, the voltage generated by the piezoelectric effect of the wafer W when an impact force is applied to the flat plate surface of the wafer W will be described. FIG. 6 is a diagram showing an example of the temporal transition of the generated voltage. Specifically, FIG. 6 (A) shows the temporal transition of the generated voltage when the impact force is applied to the front surface of the wafer W, and FIG. 6 (B) shows the time transition when the impact force is applied to the back surface of the wafer W. The time transition of the generated voltage is shown.

Further, both FIGS. 6 (A) and 6 (B) show that the lower electrode 2aU started to descend at time t1 and the upper electrode 2aU came into contact with the upper surface of the wafer W at time t2. Further, it is shown that the upper electrode 2aU is pulled away from the upper surface of the wafer W at time t3, and the upper electrode 2aU returns to the height before the start of descent at time t4.

The time from time t1 to time t2 corresponds to the descending time of the upper electrode 2aU. The time from time t2 to time t3 corresponds to the pressing time for pressing the upper electrode 2aU against the upper surface of the wafer W. The time from time t3 to time t4 corresponds to the rising time of the upper electrode 2aU, that is, the time for raising the upper electrode 2aU and returning it to the height before the start of descent.

The descending time, pressing time, and ascending time are times registered in advance in the non-volatile storage medium or the like. It may be configured so that it can be changed as appropriate. Time Ta indicates a time between time t2 and time t3.

The voltage detection unit 11 has a predetermined time interval (for example, 10 mm) from the time t1 which is the time when the upper electrode 2aU starts to descend to the time t4 which is the time when the upper electrode 2aU returns to the height before the start of the descent. Detects and records the repeatedly generated voltage in seconds).

The front / back determination unit 12 refers to, for example, the temporal transition of the generated voltage recorded from the time t1 to the time Ta, that is, from the descent start time of the upper electrode 2aU to the lapse of half of the pressing time. This is to make it possible to refer to the transition of the generated voltage when the upper electrode 2aU is brought into contact with the upper surface of the wafer W even when the actual descending time varies.

As shown in FIG. 6A, when the wafer W is set on the stage 2e with the surface of the wafer W as the upper surface, the peak value of the generated voltage when the upper electrode 2aU comes into contact with the upper surface of the wafer W is positive. It is a value and a value equal to or higher than the threshold value TH1 (positive value). On the other hand, as shown in FIG. 6B, when the wafer W is set on the stage 2e with the back surface of the wafer W as the upper surface, the peak value of the generated voltage when the upper electrode 2aU comes into contact with the upper surface of the wafer W. Is a negative value and is smaller than the threshold value TH2 (negative value) (absolute value is large). The absolute value of the peak value of the generated voltage is, for example, about several tens of mV to several V.

The threshold value TH1 and the threshold value TH2 are values registered in advance in the non-volatile storage medium of the control device 1, and are determined according to the material, size, thickness, type, contact position of the upper electrode 2aU, and the like of the wafer W.

For example, even if the peak value of the pulse-shaped generated voltage generated when the upper electrode 2aU comes into contact with the upper surface of the wafer W is a positive value, the front / back determination unit 12 can be used as long as it is less than the threshold value TH1. Is determined to be indistinguishable. Similarly, even if the peak value of the pulsed generated voltage generated when the upper electrode 2aU comes into contact with the upper surface of the wafer W is a negative value, if the absolute value is less than the absolute value of the threshold value TH2, the wafer W It is judged that the front and back sides of the above cannot be distinguished. This is because it cannot be distinguished from noise.

On the other hand, the front / back determination unit 12 determines that the upper surface of the wafer W is the surface when, for example, the peak value of the generated voltage when the upper electrode 2aU contacts the upper surface of the wafer W is a positive value and the threshold value TH1 or more. ..

The front / back determination unit 12 may determine the front / back surface of the disk surface of the wafer W in consideration of the voltage generated when the upper electrode 2aU is pulled away from the upper surface of the wafer W. For example, in the front / back determination unit 12, the peak value of the voltage generated when the upper electrode 2aU comes into contact with the upper surface of the wafer W is a positive peak value (maximum value) and larger than the threshold value TH1, and the upper electrode 2aU is the wafer W. When the peak value of the generated voltage when separated from the upper surface is a negative peak value (minimum value) and the absolute value is less than the positive peak value, it may be determined that the upper surface of the wafer W is the surface.

Similarly, when the peak value of the voltage generated when the upper electrode 2aU comes into contact with the upper surface of the wafer W is a negative value and the absolute value is equal to or greater than the absolute value of the threshold value TH2, the front / back determination unit 12 of the wafer W It is determined that the upper surface is the back surface.

Further, in the front / back determination unit 12, the peak value of the voltage generated when the upper electrode 2aU comes into contact with the upper surface of the wafer W is a negative peak value, and the absolute value thereof is larger than the absolute value of the threshold value TH2. When the peak value of the generated voltage when separated from the upper surface of the wafer W is a positive peak value and less than the absolute value of the negative peak value, it may be determined that the upper surface of the wafer W is the back surface.

In this way, the front / back determination device 100 can determine the front / back of the wafer W based on the pulse waveform of the generated voltage or the positive / negative of the generated voltage.

If necessary, the front / back determination device 100 may rotate the stage 2e by a predetermined angle (for example, 10 degrees) so that the impact force is applied to another position on the disk surface of the wafer W. For some reason, the peak value of the generated voltage may become smaller depending on the position where the impact force is applied. Further, the front and back surfaces of the disk surface of the wafer W may be determined based on the peak values of the plurality of generated voltages obtained by applying the impact force to the plurality of positions. This is because the front and back sides of the disk surface of the wafer W can be determined with higher accuracy.

Next, with reference to FIG. 7, a process of determining the front and back of the wafer W by the front / back determination device 100 (hereinafter, referred to as “front / back determination process”) will be described. Note that FIG. 7 is a flowchart showing an example of front / back determination processing. The front / back determination device 100 automatically executes this front / back determination process every time the wafer W is set on the stage 2e, for example.

First, the control device 1 applies an impact force to the disk surface of the wafer W (step S1). For example, the striking force applying unit 10 of the control device 1 outputs a control signal to the striking force applying device 2 to operate the striking force applying device 2. Specifically, the impact force applying portion 10 operates the upper expansion / contraction mechanism 2bU to bring the upper electrode 2aU into contact with the upper surface of the wafer W.

After that, the control device 1 detects the generated voltage (step S2). For example, the voltage detection unit 11 of the control device 1 acquires the generated voltage detected by the voltage detection device 3. Specifically, the voltage detection device 3 repeatedly detects the voltage generated by the piezoelectric effect of the wafer W at a predetermined cycle, and transmits the detection result (detection data) to the voltage detection unit 11. The voltage detection unit 11 continuously acquires the detection data output by the voltage detection device 3.

After that, the control device 1 compares the absolute value of the generated voltage with the threshold value, and determines whether or not the absolute value of the generated voltage is equal to or greater than the threshold value (step S3). For example, the front / back determination unit 12 of the control device 1 determines whether or not the absolute value of the peak value of the generated voltage is equal to or greater than the threshold value. Specifically, the front / back determination unit 12 determines whether or not the absolute value of the positive peak value or the negative peak value of the generated voltage is equal to or greater than the threshold value.

When it is determined that the absolute value of the generated voltage is equal to or greater than the threshold value (YES in step S3), the control device 1 determines whether or not the generated voltage is a positive value (step S4). For example, the front / back determination unit 12 of the control device 1 determines whether or not the peak value of the generated voltage determined that the absolute value is equal to or greater than the threshold value is a positive value.

When it is determined that the generated voltage is a positive value (YES in step S4), the control device 1 determines that the upper surface of the wafer W is the surface (step S5). For example, when the front / back determination unit 12 of the control device 1 determines that the peak value of the generated voltage is a positive value, it determines that the upper surface of the wafer W is the front surface.

When it is determined that the generated voltage is a negative value (NO in step S4), the control device 1 determines that the upper surface of the wafer W is the back surface (step S6). For example, when the front / back determination unit 12 of the control device 1 determines that the peak value of the generated voltage is a negative value, it determines that the upper surface of the wafer W is the back surface.

On the other hand, when it is determined that the absolute value of the generated voltage is less than the threshold value (NO in step S3), the control device 1 determines that the front and back surfaces of the wafer W cannot be determined (step S7). For example, when the front / back determination unit 12 of the control device 1 determines that the absolute value of the peak value of the generated voltage is less than the threshold value, it determines that the front / back of the wafer W cannot be determined.

After that, the control device 1 outputs the determination result (step S8). For example, when the front / back determination unit 12 of the control device 1 determines that the upper surface of the wafer W is the front surface, it displays a text message notifying that fact on the display or outputs a voice message notifying that fact from the speaker. .. The same applies to the case where it is determined that the back surface is the back surface, or the case where the determination is not possible.

With the above configuration, the front / back determination device 100 applies a striking force to the disk surface of the wafer W while supporting the wafer W on the stage 2e, and compresses the wafer W. Then, the front / back determination device 100 detects the voltage generated by the piezoelectric effect of the wafer W to be compressed, and determines the front / back surface of the disk surface of the wafer W based on the positive / negative of the generated voltage. As a result, the front / back determination device 100 can determine the front / back surface of the disk surface of the wafer W according to the polarization direction of the wafer W, which cannot be determined by a method using optical means such as X-rays or lasers. Further, the apparatus configuration can be simplified by integrating the mechanism for applying the impact force to the wafer W and the mechanism for detecting the generated voltage. Specifically, since the electrode is momentarily brought into contact with the disk surface of the wafer W to give an impact force, the end face of the wafer W is vibrated, and the electrode is brought into contact with the wafer W in advance. Compared with the configuration and the like, the front and back surfaces of the disk surface of the wafer W can be determined with a simpler configuration and a simpler calculation. Therefore, the cost can be reduced and the size can be reduced, and it can be easily incorporated into other devices such as a chamfering device that operates unmanned. Further, since the front and back sides of the disk surface of the wafer are determined by a simple calculation, it is unlikely that the determination cannot be made.

Further, the front / back determination device 100 can determine the front / back surface of the disk surface of the wafer W without forming an additional orientation flat or a gap or a fine groove as a mark on the wafer W. Therefore, the timing for determining the front and back surfaces of the disk surface of the wafer W is not limited before the specific processing or processing is performed, or is not limited after the specific processing or processing is performed.

Next, the beveling device 100A as a chamfering device incorporating the front / back determination device according to the embodiment of the present invention will be described with reference to FIGS. 8 and 9. FIG. 8 is a functional block diagram of the beveling device 100A. FIG. 9 is a schematic view of the beveling device 100A. Specifically, FIG. 9A is a top view of the beveling device 100A, and FIG. 9B is a side view of the beveling device 100A.

The beveling device 100A is a device that chamfers and grinds the outer periphery of the wafer W, and mainly includes a control device 1, a striking force applying device 2, a voltage detecting device 3, and an output device 4, which are components of the front and back determination device. , The transport device 5 and the chamfer grinding device 50.

The transport device 5 includes a stage 5a that supports the wafer W, a suction mechanism 5b that vacuum sucks the wafer W, a linear motor 5c, a linear motor guide 5d, and the like.

The suction mechanism 5b includes a vacuum suction arm 5b1, an air cylinder 5b2, and a vacuum suction arm shaft 5b3. The suction mechanism 5b is moved horizontally by the linear motor 5c along the linear motor guide 5d as shown by the arrow AR1 in FIG. 9A. Stage 5a does not move.

The transfer device 5 moves the suction mechanism 5b to the wafer cassette by, for example, the linear motor 5c. The suction mechanism 5b sucks only one wafer W in the wafer cassette. Specifically, the transfer device 5 drives the air cylinder 5b2 to extend the vacuum suction arm shaft 5b3 downward, and the wafer W in the wafer cassette is provided by the vacuum suction arm 5b1 attached to the tip of the vacuum suction arm shaft 5b3. Only one sheet is adsorbed. Then, after driving the air cylinder 5b2 and retracting the vacuum suction arm shaft 5b3 upward, the suction mechanism 5b is moved to the stage 5a by the linear motor 5c. After that, the suction mechanism 5b places the sucked wafer W on the stage 5a. Specifically, the transfer device 5 extends the vacuum suction arm shaft 5b3 downward as shown by the dotted line in FIG. 9B, and positions the wafer W sucked by the vacuum suction arm 5b1 on the stage 5a. Then, the vacuum suction by the vacuum suction arm 5b1 is released. The wafer W may be centered by a centering mechanism such as a mechanical clamp or a laser micrometer.

After that, the front / back determination process is executed. In the front / back determination process, the front / back of the wafer W is determined by evaluating the voltage waveform pattern due to the piezoelectric effect of the wafer W. An oscilloscope as a voltage detection device 3 is used for recording the waveform pattern, and a control device 1 is used for evaluating the waveform pattern. A display as an output device 4 capable of displaying the evaluation result is connected to the control device 1. The evaluation result may be displayed on the display 3a of the oscilloscope. The probe of the oscilloscope is made to collide with the upper surface of the wafer W by the impact force applying device 2 in order to generate a voltage due to the piezoelectric effect.

The impact force applying device 2 includes, for example, a probe holding portion 2a1, an air cylinder 2a2, and a probe shaft 2a3. Specifically, the probe of the oscilloscope is attached to the probe holding portion 2a1 at the tip of the probe shaft 2a3 that the air cylinder 2a2 expands and contracts. Then, when the probe shaft 2a3 extends downward, the probe is configured to come into contact with the upper surface of the wafer W. The probe may be pulled up from the upper surface of the wafer W to a predetermined height by the air cylinder 2a2 and then hit against the upper surface of the wafer W by free fall. Further, the probe holding portion 2a1 may be attached to the probe shaft 2a3 via a compression spring as described above. This is to prevent an excessive impact from being applied to the wafer W. The grounding probe of the oscilloscope is arranged so as to be in contact with the lower surface of the wafer W placed on the stage 5a, for example.

When the probe of the oscilloscope is struck on the upper surface of the wafer W, a voltage due to the piezoelectric effect is generated. The voltage due to the piezoelectric effect is detected through the probe of the oscilloscope in contact with the wafer W. The voltage fluctuation due to the piezoelectric effect lasts only for a short time on the order of microseconds. Further, if the contact time between the probe and the wafer W is long, extra noise may be picked up. Therefore, the contact time between the probe and the wafer W is preferably set to be several tens of microseconds to several hundreds of milliseconds. However, the probe of the oscilloscope may be brought into contact with the upper surface of the wafer W before generating the voltage due to the piezoelectric effect. In this case, a contact body (for example, an insulator) other than the probe as the contact body is configured to be struck on the wafer W.

The impact force applying device 2 is configured to be movable together with the suction mechanism 5b. This is so that the front / back determination process can be executed at a place other than the place where the stage 5a is installed.

Wafer W is hit by an oscilloscope probe on stage 5a. The probe is lowered by the impact force applying device 2 so as to lightly hit the wafer W. The waveform of the voltage due to the piezoelectric effect of the wafer W at the time of impact is recorded by an oscilloscope. The oscilloscope is connected to the control device 1 via an analog cable. The control device 1 automatically evaluates the voltage waveform due to the piezoelectric effect of the wafer W, determines the front and back sides of the wafer W, and displays the determination result on the display. For example, the control device 1 determines whether or not the front and back arrangement of the wafer W is a desired front and back arrangement. The desired front-back arrangement refers to, for example, the case where the upper surface of the wafer W placed on the stage 5a is the front surface. The case where the upper surface of the wafer W placed on the stage 5a is the back surface may be the desired front-back arrangement.

When the control device 1 determines that the front and back arrangement of the wafer W is not the desired front and back arrangement, that is, when it is determined that the front and back arrangement is incorrect, the control device 1 outputs an alarm notifying that fact. Specifically, a display to that effect is displayed. You may sound an audible alarm. Further, a program for promoting the wafer reversal work may be executed. For example, the operator may be notified to invert the wafer W on the stage 5a. The front and back determination processing is performed again on the inverted wafer W. Further, the wafer W may be automatically inverted. Further, a message prompting the disposal of the wafer W may be output. Further, when the front / back determination process is redone, the stage 5a may be rotated by a predetermined angle (for example, 10 degrees) so that the impact force is applied to another position on the disk surface of the wafer W.

When it is determined that the front and back arrangement of the wafer W is the desired front and back arrangement, the control device 1 automatically conveys the wafer W to the chamfer grinding device 50 as shown by the arrow AR2 in FIG. 9B. For example, the control device 1 outputs a control signal to the transfer device 5 to operate the suction mechanism 5b and the linear motor 5c, and installs the wafer W in the chamfer grinding chamber 55 through the input port 51 of the chamfer grinding device 50. It is positioned on the grinding chuck stage 30a.

The chamfer grinding device 50 includes a chuck portion 30 that holds the wafer W when the wafer W is chamfered and ground (beveling), and a grindstone portion 40 that grinds the wafer W. The chuck portion 30 and the grindstone portion 40 are installed in the chamfer grinding chamber 55.

The chuck portion 30 includes a grinding chuck stage 30a, a grinding chuck stage spindle 30b, a spindle motor 30c, a linear motor 30d, and a linear motor guide 30e.

The grinding chuck stage 30a holds the wafer W by vacuum suction. The grinding chuck stage 30a is connected to the spindle motor 30c via the grinding chuck stage spindle 30b. The spindle motor 30c rotates about a vertical axis. The rotation speed is, for example, about 1 to 10 RPM.

The grinding chuck stage 30a is moved horizontally by the linear motor 30d along the linear motor guide 30e as shown by the arrow AR3 in FIG. 9B.

The wafer W held by the grinding chuck stage 30a by vacuum suction is moved in the horizontal direction together with the grinding chuck stage 30a and comes into contact with the grindstone portion 40.

The grindstone portion 40 includes a diamond grindstone 40a, a grindstone spindle 40b, and a spindle motor 40c.

The diamond grindstone 40a is connected to the spindle motor 40c via the grindstone spindle 40b and is rotated at a high speed in order to obtain a grinding force. The spindle motor 40c rotates about a vertical axis. The peripheral speed of the diamond grindstone 40a is, for example, about 400 to 1200 meters per minute in the case of a wafer made of 4 to 6 inch lithium tantalate crystals.

The diamond grindstone 40a has a desired round grindstone cross section, and the wafer W can be chamfered at the same time as the beveling process. The chamfer grinding device 50 performs the beveling process while injecting the coolant 57 from the coolant nozzle 56. In order to make a sub-orientation flat in the beveling process or to perform beveling processing of the main orientation flat, the horizontal position of the wafer W and the horizontal movement distance via the linear motor guide 30e are set. It may be finely adjusted for each rotation angle of the wafer W. Wafer W is finished to a desired diameter by beveling.

When the beveling process is completed, the transfer device 5 automatically transfers the wafer W from the chamfer grinding chamber 55 through the input port 51 to the stage 58 after grinding, as shown by the arrow AR4 in FIG. 9B.

With the above configuration, the beveling device 100A sets the wafer W based on the determination result of the front / back determination device, and then chamfers the wafer W. Therefore, chamfer grinding of the outer periphery of the wafer W can be performed while more reliably preventing the occurrence of an irreversible situation caused by a mistake on the front and back of the wafer W.

Next, with reference to FIG. 10, the beveling device 100B as a chamfering device incorporating the front / back determination device according to the embodiment of the present invention will be described. FIG. 10 is a functional block diagram of the beveling device 100B. The beveling device 100B is different from the beveling device 100A of FIG. 8 in that it includes a reversing device 6, but is common in other points. Therefore, the description of the common part will be omitted, and the difference part will be described in detail.

The reversing device 6 is a device for reversing the wafer W. For example, the reversing device 6 includes a clamping mechanism, clamps the end of the horizontally held wafer W with the clamping mechanism, and rotates the clamping mechanism around the horizontal axis to invert the wafer W upside down. The reversing device 6 may be configured by using another known mechanism.

The control device 1 outputs a control signal to the reversing device 6 to operate the reversing device 6. The control device 1 operates the reversing device 6 when, for example, determines that the front and back arrangement of the wafer W is not the desired front and back arrangement.

When the reversing device 6 is operated, the control device 1 makes sure that the front and back determination of the inverted wafer W is redone. For example, when the reversing device 6 is operated, the control device 1 keeps the inverted wafer W at the chamfer grinding device 50 by the transport device 5 until the front and back determination of the inverted wafer W is redone. To prevent automatic transport to.

Here, with reference to FIG. 11, the front-back determination process executed by the beveling device 100B of FIG. 10 will be described. FIG. 11 is a flowchart showing an example of front / back determination processing executed by the beveling device 100B. The beveling device 100B automatically executes this front / back determination process every time the wafer W is set on the stage 5a, for example.

The front / back determination process of FIG. 11 is the same as the front / back determination process of FIG. 7 for steps S1 to S7. Therefore, the other steps will be described in detail.

When the control device 1 determines that the front and back arrangement of the wafer W is the desired front and back arrangement, the control device 1 performs automatic transfer.

For example, when the control device 1 determines that the upper surface of the wafer W is the surface (step S5), the control device 1 performs automatic transfer (step S8a). The control device 1 outputs a control signal to the transfer device 5, for example, to operate the transfer device 5. The transfer device 5 drives the air cylinder 5b2 to extend the vacuum suction arm shaft 5b3 downward, and sucks the wafer W on the stage 5a by the vacuum suction arm 5b1 attached to the tip of the vacuum suction arm shaft 5b3. Then, after driving the air cylinder 5b2 and retracting the vacuum suction arm shaft 5b3 upward, the suction mechanism 5b is moved to the chamfer grinding device 50 by the linear motor 5c. After that, the suction mechanism 5b extends the vacuum suction arm shaft 5b3 downward, and places the wafer W sucked by the vacuum suction arm 5b1 on the grinding chuck stage 30a. Then, the vacuum suction by the vacuum suction arm 5b1 is released.

On the other hand, when the control device 1 determines that the front and back arrangement of the wafer W is not the desired front and back arrangement, the chamfer grinding (chamfering) by the beveling device 100B is stopped.

For example, when the control device 1 determines that the upper surface of the wafer W is the back surface (step S6), the control device 1 stops the automatic transfer (step S8b). Then, the control device 1 inverts the wafer W (step S9). The control device 1 outputs a control signal to, for example, the transfer device 5 and the reversing device 6 to operate the transfer device 5 and the reversing device 6. The transfer device 5 sucks the wafer W on the stage 5a with the vacuum suction arm 5b1. Then, the air cylinder 5b2 is driven to retract the vacuum suction arm shaft 5b3 upward. The reversing device 6 clamps the end portion of the wafer W lifted by the conveying device 5 with a clamping mechanism. At this time, the transport device 5 releases the vacuum suction. After that, the reversing device 6 reverses the wafer W up and down by rotating the clamp mechanism around the horizontal axis. After that, the transfer device 5 sucks the inverted wafer W with the vacuum suction arm 5b1, drives the air cylinder 5b2 to extend the vacuum suction arm shaft 5b3 downward, and spreads the inverted wafer W on the stage 5a. Put in. As a result, the beveling device 100B can determine the front and back sides of the disk surface of the inverted wafer W again.

The beveling device 100B again determines whether or not the front-back arrangement of the inverted wafer W is the desired front-back arrangement, and if it is determined that the front-back arrangement is the desired front-back arrangement, the operation (chamfering) is performed. continue. Specifically, the inverted wafer W is automatically transported to the chamfer grinding apparatus 50.

Alternatively, when the control device 1 determines that the front and back surfaces of the wafer W cannot be determined (step S7), the control device 1 cancels the automatic transfer (step S8c). Then, the control device 1 stops the front / back determination by the beveling device 100B (step S10). The control device 1 outputs a control signal to, for example, the impact force applying device 2, the transport device 5, and the chamfer grinding device 50 to stop the impact force applying device 2, the transport device 5, and the chamfer grinding device 50. Then, the control device 1 outputs a control signal to the output device 4 and outputs a warning notifying that the front and back surfaces of the wafer W cannot be determined.

With the above configuration, the beveling device 100B can perform chamfer grinding of the outer periphery of the wafer W while more reliably preventing the occurrence of an irreversible situation due to a mistake on the front and back of the wafer W.

Next, with reference to FIG. 12, the beveling device 100C as a chamfering device incorporating the front / back determination device according to the embodiment of the present invention will be described. FIG. 12 is a schematic plan view of the beveling device 100C. The dashed line in FIG. 12 shows the wafer W placed on various stages.

The beveling device 100C includes a wafer cassette 302, a preparation chamber 304, a chamfer grinding chamber 306 (306a, 306b), a post-processing chamber 308, and a transfer mechanism 310.

The wafer cassette 302 is a container for holding the wafer W. The wafer cassette 302 is preferably, for example, a container capable of holding a plurality of wafers W together.

The preparation chamber 304 is a place where preparations are performed before the wafer W is transferred from the wafer cassette 302 to the chamfering grinding chamber 306. In the example of FIG. 12, the front / back determination device 100 is incorporated in the preparation chamber 304. That is, an upper expansion / contraction mechanism 2bU as a striking force applying mechanism and a lower expansion / contraction mechanism 2bD as a support mechanism are provided in the preparation chamber 304. The upper telescopic mechanism 2bU and the lower telescopic mechanism 2bD are connected to the control device 1 as shown in FIG. The wafer W transferred from the wafer cassette 302 by the transfer mechanism 310 is placed on the stage 2e. After that, the control device 1 detects the position of the orientation flat using the orientation flat detection device 7, and rotates the wafer W placed on the stage 2e to a desired relative rotation angle with respect to the reference rotation angle. Then, the upper expansion / contraction mechanism 2bU and the lower expansion / contraction mechanism 2bD are controlled to apply an impact force to the upper surface of the wafer W, and the front and back surfaces of the wafer W are determined.

The beveling process in the chamfering grinding room 306 must be performed with the front and back surfaces of the wafer W in the correct state. Therefore, when the control device 1 determines that the front and back arrangement of the wafer W is not the desired front and back arrangement, the beveling device 100C may be temporarily stopped. Further, the beveling process by the beveling device 100C may be started after the front and back surfaces of the wafer W are inverted by using the transfer mechanism 310.

In the chamfering grinding chamber 306, beveling is performed so that the diameter and shape of the wafer W become a desired diameter and shape. The chamfer grinding chamber 306 is provided with a grinding chuck stage 30a, a grindstone portion 40, and a grindstone moving mechanism 44. The grinding chuck stage 30a is a disk-shaped member on which the wafer W is placed. A rotation mechanism such as a spindle motor is connected to the grinding chuck stage 30a via a grinding chuck stage spindle. The rotation mechanism can rotate the wafer W placed on the grinding chuck stage 30a at a desired rotation speed. The grinding chuck stage 30a may include a chuck mechanism such as a vacuum chuck for securely fixing and holding the wafer W. The grindstone portion 40 is moved relative to the wafer W by the grindstone moving mechanism 44, and the rotating wafer W is chamfered and ground. The grindstone moving mechanism 44 may be configured by, for example, a ball screw, an electric actuator, or the like that can be controlled from the outside.

In the example of FIG. 12, two chamfering grinding chambers 306a and 306b are provided. This is because the beveling process takes longer than the pretreatment in the preparation chamber 304 and the posttreatment in the posttreatment chamber 308. With this configuration, the beveling device 100C can efficiently perform the beveling process. However, the number of chamfer grinding chambers 306 is not limited to two. The number of chamfering grinding chambers 306 is determined according to, for example, the beveling processing time in the chamfering grinding chamber 306, and may be one or three or more.

The after-treatment chamber 308 is a place where the post-treatment is performed on the beveled wafer W in the chamfer grinding chamber 306. The wafer W that has been beveled in the chamfer grinding chamber 306 is transported to the post-processing chamber 308 by the transport mechanism 310. In the aftertreatment chamber 308, processing such as cleaning of the wafer W is performed. After cleaning, the wafer W is carried out from the beveling device 100C.

With the above configuration, the beveling device 100C can perform chamfer grinding of the outer periphery of the wafer W while more reliably preventing the occurrence of an irreversible situation caused by a mistake on the front and back of the wafer W.

Although the preferred examples of the present invention have been described in detail above, the present invention is not limited to the above-mentioned examples, and various modifications and substitutions are made to the above-mentioned examples without departing from the scope of the present invention. Can be added.

For example, the front / back determination device 100 generates a voltage due to the piezoelectric effect of the wafer W by bringing the upper electrode 2aU into contact with the upper surface of the wafer W. However, the present invention is not limited to this configuration. For example, the front / back determination device 100 may generate a voltage due to the piezoelectric effect of the wafer W by bringing the electrodes into contact with the lower surface of the wafer W. Specifically, the lower electrode 2aD may be momentarily brought into contact with the lower surface of the wafer W while the upper electrode 2aU is in contact with the upper surface of the wafer W.

Further, in the above-described embodiment, the lower electrode 2aD is configured to move up and down by the lower expansion / contraction mechanism 2bD. However, the present invention is not limited to this configuration. For example, the lower electrode 2aD may be fixedly arranged so as to come into contact with the lower surface of the wafer W when the wafer W is set on the stage 2e. In this case, the lower expansion / contraction mechanism 2bD may be omitted.

Further, in the above-described embodiment, the wafer W is held so that the disk surface is horizontal during the front / back determination process. However, the present invention is not limited to this configuration. For example, the wafer W may be held so that the disk surface is inclined with respect to the horizontal plane during the front / back determination process.

1 ... Control device 2 ... Strike force applying device 2a1 ... Probe holding part 2a2 ... Air cylinder 2a3 ... Probe shaft 2aU ... Upper electrode 2aD ... Lower electrode 2bU ... Upper Telescopic mechanism 2bD ・ ・ ・ Lower telescopic mechanism 2cU ・ ・ ・ Upper insulator 2cD ・ ・ ・ Lower insulator 2d ・ ・ ・ Support unit 2e ・ ・ ・ Stage 2f ・ ・ ・ Rotating shaft 2g ・ ・ ・ Rotating mechanism 2h ・ ・ ・Support base 3 ・ ・ ・ Voltage detection device 3a ・ ・ ・ Display 4 ・ ・ ・ Output device 5 ・ ・ ・ Conveyor device 5a ・ ・ ・ Stage 5b ・ ・ ・ Suction mechanism 5b1 ・ ・ ・ Vacuum suction arm 5b2 ・ ・ ・ Air cylinder 5b3 ・ ・ ・ Vacuum suction arm shaft 5c ・ ・ ・ Linear motor 5d ・ ・ ・ Linear motor guide 6 ・ ・ ・ Inversion device 7 ・ ・ ・ Orientation flat detection device 10 ・ ・ ・ Impact force applying part 11 ・ ・ ・ Voltage detection part 12 ... Front and back judgment part 20a ... Strike part 20b ... Elastic member 20c ... Electric actuator 20d ... Housing 22a ... Support part 22b ... Electric actuator 22c ... Housing 30・ ・ ・ Chuck part 30a ・ ・ ・ Grinding chuck stage 30b ・ ・ ・ Grinding chuck stage Spindle 30c ・ ・ ・ Spindle motor 30d ・ ・ ・ Linear motor 30e ・ ・ ・ Linear motor guide 40 ・ ・ ・ Grinding part 40a ・ ・ Diamond grindstone 40b ... Grinding spindle 40c ... Spindle motor 44 ... Grinding mechanism 50 ... Chamfering grinding device 51 ... Input port 55 ... Chamfering grinding room 56 ... Coolant nozzle 57 ... Coolant 58 ・ ・ ・ Stage after grinding 100 ・ ・ ・ Front and back judgment device 100A, 100B, 100C ・ ・ ・ Beveling device 302 ・ ・ ・ Wafer cassette 304 ・ ・ ・ Preparation room 306, 306a, 306b ・ ・ ・ Chamfering grinding room 308 ・ ・ ・ Post-processing room 310 ・ ・ ・ Transfer mechanism W ・ ・ ・ Wafer

Claims (10)

It is a front-back judgment device that judges the front and back of a piezoelectric wafer.
A striking force applying portion configured to be able to apply a striking force to a predetermined position on any one of the front and back surfaces from any one direction of the front and back surfaces of the piezoelectric wafer.
A voltage detection unit that detects the voltage generated in the piezoelectric wafer according to the impact force applied by the impact force applying unit, and a voltage detection unit.
A front / back determination unit that determines the front / back surface of the piezoelectric wafer based on the pulse waveform of the voltage detected by the voltage detection unit.
Have a,
The predetermined position is a position between the center of the piezoelectric wafer and the outer edge of the piezoelectric wafer.
Front and back judgment device. The front / back determination unit determines the front / back surface of the piezoelectric wafer from the polarity of the pulse waveform of the voltage detected by the voltage detection unit.
The front / back determination device according to claim 1. The front and back determination unit determines the front and back of the piezoelectric wafer by comparing the absolute value of the voltage detected by the voltage detection unit with a predetermined threshold value.
The front / back determination device according to claim 1 or 2. The striking force applying unit includes a striking force applying mechanism that applies a striking force to either the front or back surface of the piezoelectric wafer, and when the striking force applying mechanism applies a striking force to the piezoelectric wafer. Includes a support mechanism that supports the other surface of the piezoelectric wafer.
The front / back determination device according to any one of claims 1 to 3. The striking force applying mechanism applies a striking force to the one surface of the piezoelectric wafer by striking one of the front and back surfaces of the piezoelectric wafer, and makes contact with the piezoelectric wafer. The portion has a striking portion provided with an electrode connected to the voltage detection portion.
The front / back determination device according to claim 4. The contact surface of the electrode with respect to the piezoelectric wafer is a flat surface.
The front / back determination device according to claim 5. The front and back determination unit
When the absolute value of the maximum value of the voltage is larger than the absolute value of the minimum value and the maximum value occurs before the minimum value, the surface on the side to which the impact force is applied is determined to be the surface. And
When the absolute value of the minimum value of the voltage is larger than the absolute value of the maximum value and the minimum value occurs before the maximum value, the surface on the side to which the impact force is applied is determined to be the back surface. To do
The front / back determination device according to any one of claims 1 to 6. The front / back determination device according to any one of claims 1 to 7 is provided.
A chamfering device that chamfers the piezoelectric wafer after setting the piezoelectric wafer based on the determination result of the front and back determination device. When the front / back determination unit determines that the front / back arrangement of the piezoelectric wafer is not the desired front / back arrangement, the chamfering process is stopped.
The chamfering device according to claim 8. When the front / back determination unit determines that the front / back arrangement of the piezoelectric wafer is not the desired front / back arrangement, the front / back of the piezoelectric wafer is inverted to continue the chamfering process.
The chamfering device according to claim 8.

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