JP6637831B2 - Device manufacturing method and grinding device - Google Patents

Description

  The present invention relates to a manufacturing method for manufacturing a device from a wafer, and a grinding apparatus for grinding a wafer.

  2. Description of the Related Art In a semiconductor device manufacturing process, devices such as ICs and LSIs are formed in respective regions defined by scheduled dividing lines on the surface of a semiconductor wafer. Then, after grinding the back surface of the wafer to reduce the thickness to a predetermined thickness, the semiconductor wafer is cut along the dividing lines and divided into chips, whereby individual semiconductor devices are manufactured. Semiconductor devices manufactured in this manner are widely used in various electric appliances.

  In order to select only non-defective chips having a thickness within an allowable range from wafers that have been cut, the thickness of each chip is measured after the wafer is divided into chips. For example, in a laminated device in which a plurality of semiconductor device chips are laminated in a three-dimensional direction, a laminated wafer in which chips having a thickness within an allowable value are laminated on a wafer is formed, and this laminated wafer is further divided into individual chips. (For example, see Patent Document 1).

JP 2013-145926 A

  Measuring the thickness of the divided chips is one of the important steps in the device manufacturing process, but in order to measure the thickness of each chip, measure the thickness by sandwiching the chip from above and below with a measuring device for each chip. Therefore, there is a problem that it takes much time to measure the thickness of the chip for obtaining a good chip.

  Therefore, when manufacturing chips by dividing the wafer, there is a problem that the thickness of each manufactured chip is grasped in a short time, and a good chip is efficiently obtained.

  According to a first aspect of the present invention, there is provided a grinding process for grinding a back surface of a wafer having a mark indicating a crystal orientation and having a surface divided by a planned dividing line and having a device formed thereon, using a grinding wheel, After the grinding step, but before the dividing step, the thickness of each chip is measured. A storage step of storing the measured chip position data and the chip thickness value in association with each other, and an allowable thickness range preset based on the chip thickness value and the position data stored in the storage step after the division step And a pickup step of selecting and picking up a chip in the device.

  According to a second aspect of the present invention, there is provided a groove which forms a groove which does not penetrate to the back surface along the planned dividing line on the front surface of a wafer which is provided with a mark indicating a crystal orientation and is divided on the front surface by a planned dividing line to form a device. A forming step, a grinding step of grinding the back surface of the wafer, a dividing step of exposing the groove from the back surface side by grinding the back surface to divide the wafer into chips, and placing the wafer divided into chips in a plane direction. An expanding step of expanding the chip interval by expanding the chip position data and chip position data obtained by measuring and measuring the thickness of each chip from after the dividing step to before the expanding step. A storage step of storing the thickness values of the chips in association with the thickness values of the chips and after the expanding step, based on the thickness values of the chips and the position data stored in the storage step. A pickup step for picking up selected chips within the acceptable thickness range which is a method of manufacturing a device comprising a.

  According to a third aspect of the present invention, a modified layer forming step of forming a modified layer inside a wafer provided with a mark indicating a crystal orientation and having a device partitioned on a surface thereof by a dividing line on the surface and along the dividing line A grinding step of grinding the rear surface of the wafer, a dividing step of generating a crack starting from the modified layer toward the front surface by grinding the rear surface to divide the wafer into chips, and dividing the wafer into chips. An expanding step of expanding the wafer in a plane direction to increase a chip interval, and a chip having a thickness measured and measured for each chip from after the dividing step to before the expanding step. A storage step of storing the position data of the chip and the chip thickness value in association with each other, and after the expanding step, based on the chip thickness value and the position data stored in the storage step. Can a method of manufacturing a device comprising a pickup step for picking up selected chips within the acceptable thickness range set in advance, the.

  According to a fourth aspect of the present invention, there is provided a holding means for holding, via a protective member, a front surface of a wafer provided with a mark indicating a crystal orientation and having a surface partitioned by a line to be divided and having a device formed thereon, and a grinding means for grinding a back surface of the wafer. A thickness measuring means for measuring the thickness of the wafer in a non-contact manner, and a data processing means for processing the data obtained by the thickness measuring means, wherein the holding means, the back surface of the wafer upside A holding table for holding the surface of the wafer protected by the protection member, rotating means for rotating the holding table around the center of the holding table, and a rotation angle of the holding table rotated by the rotating means. An angle recognizing unit that emits measurement light from above the wafer held by the holding table, and a counter that reflects the measurement light reflected from the wafer. A light receiving unit for receiving light; a thickness measuring device for measuring a thickness of the wafer from an optical path difference between reflected light reflected on the back surface of the wafer and light reflected on the front surface of the wafer, the light receiving unit receiving the light; Moving means for moving the measuring device at least in the radial direction of the wafer, and a radial position recognizing unit for recognizing the position of the thickness measuring device, wherein the data processing means is provided at the measurement point measured by the thickness measuring device. From the rotation angle of the holding table recognized by the angle recognition unit and the radial position of the thickness measuring device recognized by the radial position recognition unit, the plane direction of the wafer at the measurement point with reference to the mark formed on the wafer A calculating unit that calculates the position data, and a storage unit that stores the position data calculated by the calculating unit in association with the thickness value of the chip at each measurement point measured by the thickness measuring device, In association with the storage unit is a grinding machine which made it possible to pass the machining apparatus to be used after dividing step and said position data and said thickness seen value of the memory chips.

  The manufacturing method of the device according to the present invention is a method of measuring the thickness of each chip, measuring the thickness of each chip, and measuring the thickness of each chip, from after the grinding step to before the dividing step, or from after the dividing step to before the expanding step. A storage step of storing the thickness value in association with the thickness value is performed, and the position of the chip at the wafer level is stored. Then, by performing a pickup step of selecting and picking up a chip within a preset allowable thickness range based on the chip thickness value and position data stored in the storage step, it is not necessary to uselessly pick up the chip, In addition, since it is not necessary to measure the thickness of the chip by holding the chip from above and below with a measuring device for each chip, the thickness of each chip can be grasped in a short time without taking much time for thickness measurement, and efficient chips can be efficiently obtained. It is possible to obtain.

  Further, in the grinding device according to the present invention, the holding means includes a holding table for holding the front surface of the wafer protected by the protection member with the back surface of the wafer facing up, and a rotation for rotating the holding table around the center of the holding table. Means, and an angle recognizing unit for recognizing a rotation angle of the holding table rotated by the rotating means, wherein the thickness measuring means includes a light emitting unit for emitting measuring light from above the wafer held on the holding table, and a measuring light. A light receiving unit for receiving the reflected light reflected by the wafer, and a thickness measuring device for measuring the thickness of the wafer from an optical path difference between the reflected light reflected on the back surface of the wafer and the reflected light reflected on the front surface of the wafer. A thickness measuring device, a moving means for moving the thickness measuring device at least in the radial direction of the wafer, and a radial position recognizing section for recognizing a position of the thickness measuring device. From the rotation angle of the holding table recognized by the angle recognition unit at the measurement point measured by the measuring device and the radial position of the thickness measuring device recognized by the radial position recognition unit, the measurement point based on the mark formed on the wafer A calculation unit that calculates position data in the plane direction of the wafer, and a storage unit that stores the position data calculated by the calculation unit and the thickness value of the chip at each measurement point measured by the thickness measuring device in association with each other, Since the position data and the thickness value of the chip stored in association with each other can be transferred to the processing apparatus used after the dividing step, the chip is wastefully used by performing the method of manufacturing a device according to the present invention. It is not necessary to pick up the chips, the thickness of each chip can be grasped in a short time, and a good chip can be efficiently obtained.

It is a perspective view showing an example of a grinding device. It is a side view which shows the state which positioned the grinding wheel with respect to the back surface of the wafer. It is a side view which shows the state which grinds the back surface of a wafer with a grinding wheel. It is a side view which shows the state which measures the thickness of a wafer with a thickness measuring means. It is a top view which shows the locus | trajectory of the measurement point when measuring the thickness of a wafer with a thickness measuring instrument. FIG. 9 is a plan view showing a state in which a chip corresponding to a coordinate position of a measurement point is determined from the rotation angle of the holding table recognized by the angle recognition unit and the radial position of the thickness measuring device recognized by the radial position recognition unit. It is a perspective view showing the state where a wafer is divided by a cutting device. It is a side view showing the state where a chip is picked up by a pick-up device. FIG. 4 is a perspective view showing an example of a grinding device in which a thickness measuring unit is provided near a cleaning unit. It is a schematic diagram which shows 2nd Embodiment of this invention for every process. It is a schematic diagram which shows 3rd Embodiment of this invention for every process.

1. First Embodiment A grinding apparatus 1 shown in FIG. 1 comprises a holding means 3 for holding a wafer W, a grinding means 7 for grinding a back surface Wb of the wafer W, and a thickness measuring means for measuring the thickness of the wafer W in a non-contact manner. 4 and at least a data processing means 8 for processing the data acquired by the thickness measuring means 4.

  The wafer W has, for example, a disk-shaped outer shape, and a surface Wa of the wafer W is divided into a plurality of regions by dividing lines S arranged in a lattice, and each region is divided into a chip and a chip. Each device D such as an IC is formed. A notch N, which is a mark indicating a crystal orientation, is formed on the outer peripheral edge Wd of the wafer W so as to be recessed radially inward toward the center Wo of the wafer W. Note that the wafer W may be one in which an orientation flat, which is a mark indicating a crystal orientation, is formed by flatly notching a part of the outer peripheral edge Wd.

  When the wafer W is ground by the grinding device 1, for example, a protection member P for device protection shown in FIG. 1 is attached to the surface Wa of the wafer W to be in a protected state. The protection member P is, for example, a disk-shaped film tape having the same outer diameter as the wafer W. The protective member P for protecting the surface Wa of the wafer W is not limited to a film tape, but may be a resin member formed by dropping and spreading a liquid resin on the surface Wa of the wafer W. Is also good.

  The front (on the −X direction side) of the grinding device 1 on the base 10 is an attachment / detachment area A where the wafer W is attached / detached to / from the holding table 30 provided in the holding means 3. The rear side (+ X direction side) is a grinding area B in which the wafer W held on the holding table 30 by the grinding means 7 is ground.

  On the front side (−X direction side) of the base 10, for example, a first cassette mounting portion 110 and a second cassette mounting portion 111 are provided side by side. The first cassette 110a that houses the unprocessed wafer W is mounted thereon, and the second cassette mounting section 111 stores the second cassette 111a that stores the processed wafer W.

  A robot 12 that unloads the unprocessed wafer W from the first cassette 110a and loads the processed wafer W into the second cassette 111a is provided behind the first cassette mounting unit 110 (in the + X direction). It is arranged. At a position adjacent to the robot 12, a notch detecting means 14 for detecting a notch N of the wafer W is provided.

  The notch detection means 14 includes, for example, a detection table 140 rotatable while holding the wafer W by suction, a rotation means (not shown) for controlling the rotation operation of the detection table 140, and a wafer held by the detection table 140. A high-speed camera 141 including a CMOS image sensor and the like is positioned above W, and an image processing unit 142 that performs image processing and the like based on images captured by the high-speed camera 141.

  At a position adjacent to the notch detection means 14, a loading arm 15 which turns while holding the wafer W is arranged. The loading arm 15 suction-holds the wafer W in which the notch N has been detected by the notch detection means 14 with a suction pad, and conveys the wafer W to a holding table 30 provided in the processing area B. An unloading arm 16 that rotates while holding the processed wafer W is provided next to the loading arm 15. At a position close to the unloading arm 16, a cleaning means 17 for cleaning the processed wafer W transported by the unloading arm 16 is provided. The wafer W cleaned by the cleaning means 17 is carried into the second cassette 111a by the robot 12.

  The holding means 3 shown in FIG. 1 recognizes a holding table 30 that holds the wafer W, a rotating means 31 that rotates around a center 30c of the holding table 30, and a rotation angle of the holding table 30 that the rotating means 31 rotates. And an angle recognition unit 32. In FIG. 1, each configuration of the rotation unit 31 and the angle recognition unit 32 is schematically illustrated.

  The holding table 30 which is arranged on the base 10 of the grinding device 1 and holds the wafer W has, for example, a circular outer shape, a suction member 300 made of a porous member or the like for sucking the wafer W, and a suction table 300. And a supporting frame 301. The suction unit 300 communicates with a suction source (not shown), and the suction force generated by the suction by the suction source is transmitted to the holding surface 300a, which is the exposed surface of the suction unit 300. The wafer W is suction-held on 300a. The holding table 30 can reciprocate in the X-axis direction on the base 10 in the grinding area B.

  The rotating means 31 provided below the holding table 30 includes a rotating shaft 310 whose upper end is fixed to the bottom side of the holding table 30 and a motor 311 for rotating the rotation 310. The axial direction of the rotating shaft 310 is the Z-axis direction, and the center 30c of the holding table 30 is located on an extension of the axial center of the rotating shaft 310.

  On the lower end side of the rotating shaft 310, the angle recognition unit 32 is provided. The angle recognizing unit 32 includes, for example, a scale 320 having a disk-shaped outer shape and scales formed at equal intervals in a circumferential direction, and a reading unit 321 that reads scales of the scale 320. Is fixed to the lower end side of the rotating shaft 310 so that the axis of the rotating shaft 310 is aligned with the center. Accordingly, as the rotating shaft 310 rotates, the holding table 30 and the scale 320 rotate in the same direction as the rotating shaft 310 by the same angle.

  The reading unit 321 disposed below the scale 320 is, for example, an optical type that reads reflected light of a scale formed on the scale 320. The reading unit 321 is configured to transmit read information to the reading unit 321. The cable 321a is connected. The other end of the cable 321a is connected to the data processing means 8. Then, the angle recognition unit 32 can recognize the rotation angle of the holding table 30 based on the information read by the reading unit 321 from the scale 320. Note that the angle recognition unit 32 may be configured so that the encoder recognizes the rotation angle of the motor 311 and notifies the data processing unit 8 of the rotation angle.

  A column 19 is provided upright on the base 10 in the grinding area B (on the + X direction side), and the grinding feed means 5 is provided on a side surface of the column 19 on the −X direction side. The grinding feed means 5 includes a ball screw 50 having an axis in the vertical direction (Z-axis direction), a pair of guide rails 51 disposed in parallel with the ball screw 50, and a ball screw 50 which is connected to an upper end of the ball screw 50 to rotate the ball screw 50. A motor 52 to be driven, an elevating plate 53 having an inner nut screwed into the ball screw 50 and a side part slidingly contacting the guide rail 51, and a holder 54 connected to the elevating plate 53 and holding the grinding means 7. When the ball screw 52 rotates, the lifting plate 53 is guided by the guide rail 51 to reciprocate in the Z-axis direction, and the grinding means 7 held by the holder 54 approaches or separates from the holding table 30. Grinding feed is performed in the Z-axis direction.

  The grinding means 7 includes a spindle 70 whose axial direction is a vertical direction (Z-axis direction), a spindle housing 71 that rotatably supports the spindle 70, a spindle motor 72 that rotationally drives the spindle 70, and a lower end of the spindle 70. An annular mount 73 is connected, and a grinding wheel 74 is detachably connected to the lower surface of the mount 73.

  The grinding wheel 74 includes an annular wheel base 741 and a plurality of substantially rectangular parallelepiped grinding wheels 740 disposed annularly on the bottom surface of the wheel base 741. The grinding wheel 740 is formed, for example, by bonding diamond abrasive grains or the like with a resin bond, a metal bond, or the like. In addition, the shape of the grinding wheel 740 may be one integrally formed in a ring shape. Inside the grinding means 7, a flow path (not shown) serving as a passage for the grinding water is formed. This flow path is opened at the bottom surface of the wheel base 741 so that the grinding water can be jetted toward the grinding wheel 740. ing.

  At a position on the −Y direction side adjacent to the holding table 30 in the grinding area B, a thickness measuring unit 4 is provided. The thickness measuring device 4 recognizes the thickness measuring device 40, the moving device 41 that moves the thickness measuring device 40 at least in the radial direction of the wafer W (in the illustrated example, the Y-axis direction), and the position of the thickness measuring device 40. And a radial position recognizing unit 42 that performs the operation.

  The moving means 41 includes, for example, a ball screw 410 having an axis in a direction (Y-axis direction) orthogonal to the horizontal direction in the traveling direction (X-axis direction) of the holding table 30, and a bridge-like member that supports both ends of the ball screw 410 in a hollow state. A base 411, an arm 412 in which an internal nut is screwed into the ball screw 410 and reciprocates on the ball screw 410 in the Y-axis direction, and a motor (not shown) which is connected to one end of the ball screw 410 and rotates the ball screw 410. It has. The arm 412 extends toward the + Y direction, and a thickness measuring device 40 is provided at a tip of the arm 412 on the + Y direction side. When a motor (not shown) rotates the ball screw 410, the arm 412 reciprocates on the ball screw 410 in the Y-axis direction in accordance with the rotation, and the thickness measuring device 40 moves the holding table 30 of the holding table 30 positioned below the grinding means 7. It reciprocates upward in the Y-axis direction. In addition, the thickness measuring device 4 may be provided with a moving device that enables movement in the X-axis direction in addition to the moving device 41, so that the thickness measuring device 40 can also be moved in the X-axis direction. .

  The radial position recognition unit 42 reads, for example, a scale 420 formed on the upper surface of the base 411 so as to extend along the movement direction (Y-axis direction) of the arm unit 412, and reads position information (scale) of the scale 420. And a portion 421. The reading unit 421 is fixed to the arm unit 412 and moves in the Y-axis direction together with the arm unit 412. The reading unit 421 is, for example, an optical type that reads reflected light on the scale of the scale 420, and is located in the radial direction of the thickness measuring device 40 disposed at the tip of the arm unit 412 on the + Y direction side, that is, the Y axis. The position in the direction can be recognized.

  At a position on the + Y direction side adjacent to the holding table 30 in the grinding area B, for example, a pair of height gauges 18 for measuring the thickness of the wafer W by a contact method is provided. The pair of height gauges 18 includes a first height gauge 181 for measuring the height position of the holding surface 300a of the holding table 30, and a second height gauge 182 for measuring the height position of the back surface Wb of the wafer W. Each of the first height gauge 181 and the second height gauge 182 has a contact at the tip thereof which moves vertically. The first height gauge 181 detects the height position of the upper surface of the frame 301 serving as the reference surface, and the second height gauge 182 detects the height position of the back surface Wb of the wafer W to be ground. By calculating the difference between the values, the thickness of the wafer W can be measured at any time during grinding.

  The data processing unit 8 is connected to the thickness measuring unit 4 and the angle recognizing unit 32, and includes a calculating unit 80 including a CPU and the like, and a storage unit 81 including a storage element and the like.

  Hereinafter, the operation of the grinding device 1 and each step of the device manufacturing method when the device manufacturing method according to the present invention is performed using the grinding device 1 will be described with reference to FIGS.

(1) Grinding Step First, a grinding step of grinding the back surface Wb of the wafer W with the grinding wheel 740 is performed. For example, the wafer W to be ground is housed inside the first cassette 110a with the surface Wa of the wafer W protected by the protection member P, as shown in FIG. The robot 12 turns and enters the inside of the first cassette 110a, and sucks and holds the wafer W before grinding. Next, the robot 12 unloads the wafer W from the inside of the first cassette 110a, and places the wafer W on the inspection table 140. At this time, the wafer W is set so that, for example, the back surface Wb to be ground is on the upper side. The inspection table 140 sucks and holds the wafer W, and the robot 12 retreats from the inspection table 140.

  The high-speed camera 141 moves onto the inspection table 140 that holds the wafer W by suction, and the high-speed camera 141 is positioned so that the wafer W fits within the imaging area of the high-speed camera 141. Next, the inspection table 140 is rotated about the axis in the Z-axis direction by rotating means (not shown), and the high-speed camera 141 continuously captures the outer peripheral edge Wd of the rotating wafer W at high speed, and performs image processing. The unit 142 detects the notch N of the outer peripheral edge Wd of the wafer W by, for example, a pixel having unique color information of the outer peripheral edge Wd of the wafer W in the captured image. For example, the inspection table 140 for holding the wafer W such that a virtual line passing through the center Wo of the wafer W and the notch N is parallel to the X-axis direction and the notch N is located on the −X direction side. Rotates.

  The loading arm 15 pivots so as to be positioned on the inspection table 140, and holds the wafer W by suction. The loading arm 15 holding the wafer W by suction holds the wafer W above the holding table 30. At this time, the loading arm 15 is adjusted so that the center 30c of the holding table 30 and the center Wo of the wafer W are located at a position where they overlap when viewed from above. Next, the wafer W is placed on the holding surface 300a of the holding table 30 so that the back surface Wb is on the upper side, the holding table 30 sucks and holds the wafer W on the holding surface 300a, and the loading arm 15 is Evacuate from above.

  The wafer W is, for example, in a state where a virtual line passing through the center Wo of the wafer W and the notch N is parallel to the Y-axis direction and the notch N is located on the −Y direction side, that is, the notch N on the holding table 30. Is held in a state in which the position is grasped.

  Next, as shown in FIG. 2, the holding table 30 holding the wafer W moves in the + X direction to below the grinding unit 7, and the holding table 30 is positioned with respect to the grinding wheel 74 of the grinding unit 7. As the spindle 70 is rotationally driven by the spindle motor 72, the grinding wheel 74 rotates at a predetermined speed in a counterclockwise direction as viewed from the + Z direction side. Further, the grinding unit 7 is sent in the −Z direction by the grinding feed unit 5, the grinding wheel 74 provided in the grinding unit 7 descends in the −Z direction, and the grinding wheel 740 contacts the back surface Wb of the wafer W. Thus, a grinding process is performed. Furthermore, during the grinding, the wafer W held on the holding table 30 also rotates as the rotating means 31 rotates the holding table 30 in the counterclockwise direction as viewed from the + Z direction, so that the grinding wheel 740 is rotated. The entire back surface Wb of the wafer W is ground. As shown in FIG. 3, after grinding the wafer W to a predetermined thickness, the grinding means 7 is moved in the + Z direction by the grinding feeding means 5 shown in FIG. 1 to separate the wafer W from the ground wafer W.

(2) Storage Step For example, the rotating means 31 shown in FIG. 1 rotates the holding table 30 by a required angle, and a virtual line passing through a predetermined initial position, for example, the center Wo of the wafer W and the notch N is in the Y-axis direction. And at a position where the notch N is positioned on the −Y direction side. Next, as shown in FIG. 4, a motor (not shown) rotates the ball screw 410, and the arm 412 moves on the ball screw 410 toward the + Y direction. Along with the movement of the arm portion 412, the thickness measuring device 40 also moves above the wafer W in the radial direction, that is, in the + Y direction from the outer peripheral edge Wd on the −Y direction side of the wafer W toward the center Wo of the wafer W. Go. In addition, as the thickness measuring device 40 moves from the outer peripheral edge Wd on the −Y direction side to the center Wo of the wafer W, the speed at which the thickness measuring device 40 is sent by the moving means 41 is increased.

  The light projecting unit 400 of the thickness measuring device 40 moving above the wafer W irradiates the wafer W with measurement light (for example, laser light), and the light reflected by the back surface Wb of the wafer W received by the light receiving unit 401. The thickness measuring device 40 measures the thickness of the wafer W from the optical path difference between the light and the light reflected on the surface Wa of the wafer W.

  The moving means 41 moves the thickness measuring device 40, and the rotating means 31 rotates the holding table 30 counterclockwise as viewed from the + Z direction side with reference to the rotation angle (0 degree) of the initial position of the wafer W. Since the wafer W held on the holding table 30 also rotates, as shown in FIG. 5, the measurement point moves clockwise from the outer edge Wd of the wafer W toward the center Wo on the back surface Wb as viewed from the + Z direction. , Measuring points Q3,..., Measuring points Qk,..., Measuring points on the entire surface on the back surface Wb of the wafer W so as to draw a spiral locus of The thickness T1, thickness T2, thickness T3,..., Thickness Tk..., And thickness Tm (k and m are natural numbers) in Qm (k and m are natural numbers) are measured. In the case where the thickness measuring means 4 is provided with a moving means capable of moving in the X-axis direction in addition to the moving means 41, the thickness measuring device 40 is moved to the Y direction without rotating the holding table 30. You may make it move in an axial direction and an X-axis direction.

  The thickness measuring device 40 measures the thickness T1, the thickness T2, the thickness T3,... Of the wafer W at each measurement point Q1, the measurement point Q2, the measurement point Q3,. When the thickness Tk... And the thickness Tm are measured, the reading unit 321 reads the scales of the scale 320 shown in FIGS. 1 and 4 so that the angle recognizing unit 32 rotates the holding table 30 by the rotation angles θ1, θ2, Recognize the rotation angles θ3,..., Rotation angles θk, and rotation angles θm (k and m are natural numbers), and read and read the rotation angles of the holding table 30 (rotation angles θ1, rotation angles θ2, rotation angles θ3). ,..., Rotation angles θk..., Rotation angles θm) are output from the angle recognition unit 32 to the data processing means 8. Further, the thickness measuring device 40 measures the thickness T1, the thickness T2, the thickness T3,... Of the wafer W at each measurement point Q1, the measurement point Q2, the measurement point Q3,. Each time the thickness Tk is measured, the reading unit 421 reads the position information of the scale 420 so that the radial position recognizing unit 42 determines the radial position of the thickness measuring device 40, that is, FIG. The radial position y1, the radial position y2, the radial position y3,... The radial position yk..., The radial position ym (k and m are natural numbers) in the Y-axis direction shown in FIG. Information about the radial position (y1, y2, y3,..., Yk, ym) of the thickness measuring device 40 is output from the radial position recognition unit 42 to the data processing means 8.

  The calculation unit 80 of the data processing means 8 shown in FIG. 1 calculates the thickness of the wafer W measured by the thickness measuring device 40 (thickness T1, thickness T2, thickness T3,..., Thickness Tk..., Thickness Tm). , Measurement points Qk,..., Measurement points Qk,..., At the measurement points Qm, the rotation angles of the holding table 30 recognized by the angle recognition unit 32 (rotation angles θ1, θ2,. , Rotation angle θk, rotation angle θm) and the radial position (y1, y2, y3,..., Yk) of the thickness measuring device 40 recognized by the radial position recognition unit 42. .., ym), the position in the plane direction at each measurement point based on the notch N of the wafer W is calculated as position data in the X-axis direction and the Y-axis direction.

  For calculation of each position data in the X-axis direction and the Y-axis direction based on the notch N of the wafer W, for example, the coordinate position of the center Wo of the wafer W is determined as the origin position (0, 0). Then, for example, to calculate the position data of the measurement point Qk in the X-axis direction and the Y-axis direction shown in FIG. 6, as shown in FIG. 6, the radial position from the origin position (0, 0) in the −Y direction A virtual line L1 is drawn up to yk. Also, a virtual line L2 is drawn from the origin position (0, 0) in the direction of the rotation angle θk. Further, a virtual line L3 is drawn from the tip of the virtual line L1 in the −X direction, and the intersection of the virtual line L3 and the virtual line L2 is the measurement point Qk. Then, by measuring the distance in the X-axis direction from the virtual line L1 to the measurement point Qk, the position data of the measurement point Qk in the X-axis direction and the Y-axis direction, that is, the coordinate position (xk, yk) is calculated. You. Then, from the coordinate position (xk, yk) of the measurement point Qk, it is determined that the device formed on the surface Wa of the wafer W, that is, the chip Ck after division is measured.

  The storage unit 81 stores the coordinate position (xk, yk) of the chip Ck at the measurement point Qk on the X-axis Y-axis plane calculated by the calculation unit 80 in association with the thickness Tk measured by the thickness measuring device 40. Go. As shown in FIG. 6, when a plurality of measurement points exist on the chip like the chip Ck (in the illustrated example, there are four measurement points), each of the measurement points The average value of the thickness is defined as the thickness of the chip Ck. Thus, the storage unit 81 stores the coordinate positions of the chip C1, the chip C2, the chip C3,..., The chip Ck,. Are sequentially stored as data in association with each other. Further, the data processing means 8 transmits the data stored in the storage unit 81 to, for example, the pickup device 6 shown in FIG.

(3) Division Step After the storage step is performed, a division step of dividing the wafer W along the planned division line S into chips C is performed as shown in FIG. The division of the wafer W is performed using, for example, the cutting device 2. The wafer W is cleaned by the cleaning means 17 of the grinding device 1 shown in FIG. 1 before being transferred to the cutting device 2, and then transferred to a tape mounter (not shown). In the tape mounter, as shown in FIG. 7, the wafer W is in a state where the dicing tape P1 is adhered to the back surface Wb of the wafer and is supported by the annular frame F via the dicing tape P1. Further, the protection member P shown in FIG. 1 is peeled off from the surface Wa of the wafer W.

  The cutting device 2 shown in FIG. 7 includes a chuck table 21 for holding a wafer W, cutting means 22 having a cutting blade 220 for cutting the wafer W held on the chuck table 21, and a cutting device 22 held on the chuck table 21. And alignment means 23 for detecting the planned dividing line S of the wafer W to be cut.

  The alignment unit 23 can detect the planned division line S based on the image acquired by the camera 230. The alignment means 23 and the cutting means 22 are integrally formed, and both move in the Y-axis direction and the Z-axis direction in conjunction with each other.

  The chuck table 21 can hold the wafer W by suction on the holding surface 21a, is rotatably supported by the rotating means 21b, and can be moved in the X-axis direction by cutting feed means (not shown). Around the chuck table 21, a fixing clamp 21c for fixing the annular frame F is provided.

  The cutting means 22 is movable in the Y-axis direction and the Z-axis direction. The cutting blade 220 provided in the cutting means 22 is rotatably mounted on, for example, a spindle 222 which is rotatably housed in a spindle housing 221 and whose axial direction is a direction orthogonal to the X-axis direction in the horizontal direction (Y-axis direction). Be attached. Then, as the spindle 222 is driven to rotate by a motor (not shown), the cutting blade 220 also rotates at a high speed.

  First, the wafer W supported on the annular frame F via the dicing tape P1 is placed on the chuck table 21 such that the surface Wa of the wafer W is on the upper side. Then, the annular frame F is fixed by the fixing clamp 21c, and the wafer W is suction-held on the holding surface 21a of the chuck table 21.

  The wafer W held on the chuck table 21 is sent in the −X direction, and the position of the dividing line S at which the cutting blade 220 is cut is detected by the alignment means 23. As the planned division line S is detected, the cutting means 22 moves in the Y-axis direction, and the planned division line S to be cut and the cutting blade 220 are aligned in the Y-axis direction.

  The chuck table 21 holding the wafer W is further fed in the −X direction, and the cutting means 22 descends in the −Z direction. Further, the spindle 222 rotates, and the cutting blade 220 cuts into the wafer W while rotating along with the rotation of the spindle 222, and cuts the dividing line S.

  When the wafer W is sent to a predetermined position in the X-axis direction where the cutting blade 220 finishes cutting the planned dividing line S, the cutting feed of the wafer W is stopped once, and the cutting blade 220 is separated from the wafer W in the + Z direction. Next, the wafer W is moved in the + X direction to return to the original position. Then, the same cutting is sequentially performed while indexing and feeding the cutting blade 220 in the Y-axis direction (-Y direction in the illustrated example) at intervals of the adjacent scheduled division line S, and further, the wafer W is rotated by the rotating means 21b. By rotating the wafer 90 degrees and performing the same cutting, the wafer W is cut along all the division lines S, and the wafer W is divided into chips C.

The dividing step may be performed by any of the following methods.
(A) A method of irradiating a laser beam having a wavelength that has absorptivity to the wafer W along the planned dividing line S and performing ablation processing to completely cut the planned dividing line S into chips C.
(A) A laser beam having a wavelength that has absorptivity to the wafer W is irradiated along the planned dividing line S and ablation processing is performed to form an ablation groove in the dividing line S. Then, the wafer W is moved in the plane direction. A method of expanding into chips and dividing into chips C.
(C) After irradiating the wafer W with a laser beam having a wavelength having a transmittance along the dividing line S to form a modified layer therein, the wafer W is expanded in the plane direction to form a chip C. How to split.

(4) Pickup Step The chip C supported by the annular frame F via the dicing tape P1 is transported to the pickup device 6 shown in FIG. The pickup device 6 fixes the annular frame F with a clamp or the like (not shown), and pushes up the chip C from below via a dicing tape P1 with a needle 60 that can move up and down in the Z-axis direction. This is a device that picks up a portion that has risen from the surface by sucking and holding it with a suction pad 61.

  Here, data that associates each coordinate position of the chip C with each thickness measured by the thickness measuring device 40 has been sent from the data processing means 8 to the pickup device 6 in advance. The pickup device 6 selects and picks up a chip C within a predetermined allowable thickness range from the transmitted data. Therefore, only good products can be picked up among many chips C, and it is not necessary to uselessly pick up the chips C, and the thickness is measured by sandwiching the chips C from above and below with a measuring device for each chip C. Since the necessity is eliminated, a good chip can be efficiently obtained without taking much time for thickness measurement.

  In addition, the grinding apparatus 1 according to the present invention is not limited to the above-described embodiment, and the size and shape of each configuration illustrated in the accompanying drawings are not limited thereto. Can be changed as appropriate within a range in which can be exhibited.

  For example, a grinding device 1A shown in FIG. 9 is a device obtained by partially changing the configuration of the grinding device 1 shown in FIG. The cleaning unit 17 of the grinding apparatus 1A is, for example, a single-wafer spin type cleaning unit, and includes a holding unit 17a having a holding table 170 that is a rotatable spinner table. The rotation means 31 and the angle recognition unit 32 are provided below the holding table 170. Then, the angle recognition unit 32 is connected to the data processing unit 8.

  In the grinding device 1A, the thickness measuring means 4A is disposed at a position adjacent to the holding table 170. The thickness measuring unit 4A includes a thickness measuring unit 40, a moving unit 49 that moves the thickness measuring unit 40 at least in the radial direction of the wafer W, and a radial position recognition unit 42 that recognizes the position of the thickness measuring unit 40. I have.

  The moving means 49 includes a ball screw 490 having an axis in the Y-axis direction, a bridge-like base 491 that supports both ends of the ball screw 490 in a hollow state, and an internal nut screwed onto the ball screw 490 to move on the ball screw 490 in the Y-axis direction. And a motor (not shown) connected to one end of the ball screw 490 to rotate the ball screw 490. A thickness measuring device 40 is provided on the −X direction side surface of the movable portion 492. When a motor (not shown) rotates the ball screw 410, the movable portion 492 moves on the ball screw 490 in the Y-axis direction. The thickness measuring device 40 reciprocates above the holding table 170 in the Y-axis direction. By providing the thickness measuring means 4A with a moving means capable of moving in the X-axis direction in addition to the moving means 49, the thickness measuring device 40 may also be movable in the X-axis direction. . The radial position recognition unit 42, for example, disposes position information (scale) of the scale 420 formed on the upper surface of the base 411 extending along the moving direction (Y-axis direction) of the movable unit 492 on the movable unit 492. The reading unit 421 reads the data. The thickness measuring means 4A is connected to the data processing means 8.

  When the method for manufacturing a device according to the present invention is performed using the grinding apparatus 1A, (1) after performing the grinding step, the ground wafer W is transferred to the cleaning means 17 by the unloading arm 16, and is held by the holding means. 17a and the thickness measuring means 4A perform the (2) storing step.

  For example, in order to carry out the device manufacturing method according to the present invention, the grinding device 1 and the tape mounter to which the wafer W is transported after the (1) grinding process are arranged, and the grinding device 1 and the tape mounter are disposed between the grinding device 1 and the tape mounter. The thickness measuring means and the holding means may be independently provided. Alternatively, the tape mounter may be provided with a thickness measuring unit and a holding unit in the device. Then, (2) the storage step is performed by the thickness measuring means and the holding means independently disposed between the grinding device 1 and the tape mounter, or the thickness measuring means provided in the tape mounter. (2) The storage step may be performed with the holding unit.

2 Second Embodiment (1) Groove Forming Step For example, as shown in FIG. 10A, the dicing tape P1 side is held on the chuck table 21 of the cutting device 2 shown in FIG. 7, and the surface Wa of the wafer W is exposed. Let it. The rotating cutting blade 220 is positioned above the dividing line S, and the lower end of the cutting blade 220 is positioned below the surface Wa of the wafer W. In this state, the chuck table 21 and the cutting means 22 are positioned. Are relatively moved in the X-axis direction, thereby forming a groove G having a predetermined depth along the dividing line S. Such cutting is performed vertically and horizontally on all the division lines S.

  Note that the groove G may be formed by ablation processing using laser light irradiation. For example, as shown in FIG. 10B, the back surface Wb side of the wafer W is held on a chuck table 90 of a laser processing apparatus. The irradiation head 91 irradiates the wafer W with laser light 910 having a wavelength that has absorptivity to the wafer W, and moves the irradiation head 91 relative to the wafer W in the X-axis direction along the dividing line S. A groove G is formed by performing ablation processing on the dividing line S. Such laser processing is performed vertically and horizontally on all the division lines S.

(2) Grinding Step Next, the dicing tape P1 is peeled off from the back surface Wb, and as shown in FIG. 10 (c), the protection member P is adhered to the front surface Wa where the groove G is formed. , For example, on the holding table 30 of the grinding apparatus 1 shown in FIG. Then, the holding table 30 holding the wafer W rotates at a predetermined speed, the grinding wheel 74 rotates at a predetermined speed, and the grinding unit 7 descends, so that the rotating grinding wheel 740 grinds the back surface Wb. The wafer W is thinned.

(3) Dividing process When the wafer W is made thinner by continuing the grinding process, the groove G is exposed from the surface to be ground as shown in FIG. It is divided into C. Thereafter, the individual chips C are formed to a predetermined thickness by performing grinding as needed. In addition, even after the wafer W is divided into the chips C, the shape of the wafer W is maintained as a whole because all the chips C are in a state of being stuck to the protection member P.

(4) Storage Step After the division step, the thickness of each chip C is obtained using, for example, the thickness measuring means 4 shown in FIG. Then, the storage unit 81 sequentially stores the coordinate position of each chip and the thickness measured by the thickness measuring device 40 in association with each other as data. This step is performed in the same manner as in the first embodiment. When the thickness is measured at the position of the groove G, an appropriate value cannot be obtained. Therefore, if the thickness value obtained by the measurement is smaller than a predetermined threshold value, the value is ignored. .

(5) Expanding Step After the storing step, as shown in FIG. 10E, the expanding tape P2 is attached to the back surface of the chip C, and the expanding tape P2 is supported by the annular frame F1. Further, the protective member P is peeled off from the surface of the chip C. Then, in the expanding device, the expanding tape P2 side is placed on the table 93, the annular frame F1 is held in the frame holding portion 94, and the frame holding portion 94 is relatively moved downward with respect to the table 93, The expanding tape P2 is radially stretched in the plane direction. Then, the chip interval between adjacent chips C is increased. The expanding device quantitatively grasps the expansion amount of the expanding tape P2, and transfers the value of the expansion amount to a pickup device used in a subsequent pickup process.

(6) Pickup Step After the chip interval is expanded by the expanding step, individual chips C are picked up from the expanding tape P2. The pickup of the chip C is performed in the same manner as in the first embodiment. However, since each chip C moves in the radial direction by the expanding step, the pickup position is adjusted based on the expanding amount of the expanding tape P2. For example, by calculating the amount of deviation of each chip C in the expanding step by dividing the amount of expansion by the number of lines S to be divided, and adjusting the pickup position by the amount of deviation, a desired chip C can be picked up. Can be.

  In the second embodiment implemented according to the above procedure, the thickness of the chip C is measured after the wafer W is divided into the chips C, but in the storage step, the shape of the wafer C is maintained as a whole in the memory step. Since the thickness of the chip C is measured, it is efficient.

3. Third Embodiment (1) Modified Layer Forming Step (Formation of Modified Layer Inside with Laser)
As shown in FIG. 11A, a dicing tape P1 is attached to the back surface Wb of the wafer W, and the dicing tape P1 side is held on a chuck table 90 of a laser processing apparatus. Then, a laser beam 911 having a wavelength having transparency to the wafer W is irradiated from the irradiation head 91, and the irradiation head 91 is relatively moved with respect to the wafer W in the X-axis direction along the dividing line S. The modified layer G1 is formed inside the wafer W along the division line S. Such a modified layer forming process is performed vertically and horizontally along all the planned dividing lines S.

(2) Grinding Step Next, as shown in FIG. 11B, the protective member P is attached to the front surface Wa of the wafer W on which the modified layer G1 is formed, and the dicing tape P1 is peeled off from the rear surface Wb side. I do. Then, the protection member P side is held, for example, on the holding table 30 of the grinding apparatus 1 shown in FIG. Then, the holding table 30 holding the wafer W rotates at a predetermined speed, the grinding wheel 74 rotates at a predetermined speed, and the grinding unit 7 descends, so that the rotating grinding wheel 740 grinds the back surface Wb. The wafer W is thinned.

(3) Dividing Step As the wafer W is made thinner by continuing the grinding step, a crack CR is formed on the surface Wa side starting from the modified layer G1 as shown in FIG. 11C. The wafer W is divided into individual chips C along the planned dividing line S by the formed and modified layer G1 and the crack CR. Thereafter, individual chips C are formed to a predetermined thickness by performing grinding as needed. In addition, even after the wafer W is divided into the chips C, the shape of the wafer W is maintained as a whole because all the chips C are in a state of being stuck to the protection member P.

(4) Storage Step After the division step, the thickness of each chip C is obtained using, for example, the thickness measuring means 4 shown in FIG. Then, the storage unit 81 sequentially stores the coordinate position of each chip and the thickness measured by the thickness measuring device 40 in association with each other as data. This step is performed in the same manner as in the first embodiment and the second embodiment.

(5) Expanding Step After the storing step, as shown in FIG. 11D, an expanding tape P2 is attached to the back side of the chip C, and the expanding tape P2 is supported by the annular frame F1. Further, the protective member P is peeled off from the surface of the chip C. Then, in the expanding device, the expanding tape P2 side is placed on the table 93, the annular frame F1 is held in the frame holding portion 94, and the frame holding portion 94 is relatively moved downward with respect to the table 93, The expanding tape P2 is radially stretched in the plane direction. Then, the chip interval between adjacent chips C is increased. The expanding device quantitatively grasps the expansion amount of the expanding tape P2, and transfers the value of the expansion amount to a pickup device used in a subsequent pickup process.

(6) Pickup Step After the chip interval is expanded by the expanding step, individual chips C are picked up from the expanding tape P2. The pickup of the chip C is performed in the same manner as in the first embodiment. However, since each chip C moves in the radial direction by the expanding step, the pickup position is adjusted based on the expanding amount of the expanding tape P2. For example, by calculating the amount of deviation of each chip C in the expanding step by dividing the amount of expansion by the number of lines S to be divided, and adjusting the pickup position by the amount of deviation, a desired chip C can be picked up. Can be.

  In the third embodiment implemented according to the above procedure, the thickness of the chip C is measured after the wafer W is divided into the chips C, but in the storage step, the shape of the wafer W is maintained as a whole in the memory step. Since the thickness of the chip C is measured, it is efficient.

1: Grinding device 10: Base A: Detachable area B: Grinding area
110: first cassette mounting portion 110a: first cassette
111: second cassette mounting portion 111a: second cassette 12: robot
14: Notch detection means 140: Detection table 141: High-speed camera
142: Image processing unit
15: Loading arm 16: Unloading arm
17: Cleaning means 18: A pair of height gauges
19: Column 2: Cutting device 21: Chuck table 22: Cutting means 23: Alignment means 30: Holding table 300: Suction unit 300a: Holding surface 301: Frame
30c: center of chuck table 31: rotating means 310: rotating shaft 311: motor
32: Angle recognition unit 320: Scale 321: Reading unit 321a: Cable 4: Thickness measuring unit 40: Thickness measuring device 400: Light emitting unit 401: Light receiving unit 41: Moving unit 410: Ball screw 411: Base unit 412: Arm unit
42: radial position recognition unit 420: scale 421: reading unit 5: grinding feed means 50: ball screw 51: guide rail 52: motor
53: lifting plate 54: holder 7: grinding means 70: spindle 71: spindle housing
72: spindle motor 73: mount
74: grinding wheel 740: grinding wheel 741: wheel base 8: data processing means 80: calculation unit 81: storage unit W: wafer Wa: front surface of wafer Wb: back surface of wafer Wd: outer peripheral edge of wafer Wo: center of wafer N: Notch S: Planned dividing line D: Device C: Chip P: Protection member
P1: dicing tape F: annular frame 6: pickup device 60: needle 61: suction pad 1A: grinding device 4A: thickness measuring means 49: moving means

Claims (4)

A grinding step of grinding the back surface of the wafer, which has a mark indicating the crystal orientation on the front surface and divided by a planned dividing line on the surface to form a device, with a grinding wheel, and after the grinding step, divides the wafer along the dividing line. A dividing process into chips, and a device manufacturing method comprising:
A storage step of measuring the thickness of each chip from before the grinding step to before the division step and storing the measured chip position data and the chip thickness value in association with each other; and A pickup step of selecting and picking up a chip within a preset allowable thickness range based on the stored chip thickness value and the position data. A groove forming step of forming a groove that does not penetrate to the back surface along the planned dividing line on the front surface of the wafer on which the device is formed by being divided by the planned dividing line on the front surface with a mark indicating the crystal orientation,
A grinding step of grinding the back surface of the wafer;
A dividing step of dividing the wafer into chips by exposing the grooves from the back side by grinding the back side;
An expanding step of expanding the wafer divided into chips in the surface direction to increase the chip interval,
A method for manufacturing a device comprising:
Performing a storage step of measuring the thickness of each chip from before the expanding step to before the expanding step and associating the measured chip position data and the chip thickness value with each other,
After the expanding step, a pickup step of selecting and picking up a chip within a preset allowable thickness range based on the thickness value and the position data of the chip stored in the storage step,
A method for manufacturing a device including: A modified layer forming step of forming a modified layer along the planned dividing line inside the wafer in which the device is formed by being divided by the planned dividing line on the surface with a mark indicating the crystal orientation,
A grinding step of grinding the back surface of the wafer;
A dividing step of dividing the wafer into chips by generating cracks starting from the modified layer toward the front surface by grinding the back surface;
An expanding step of expanding the wafer divided into chips in the surface direction to increase the chip interval,
A method for manufacturing a device comprising:
Performing a storage step of measuring the thickness of each chip from before the expanding step to before the expanding step and associating the measured chip position data and the chip thickness value with each other,
After the expanding step, a pickup step of selecting and picking up a chip within a preset allowable thickness range based on the thickness value and the position data of the chip stored in the storage step,
A method for manufacturing a device including: Holding means for holding, via a protective member, a surface of a wafer having a mark indicating a crystal orientation and having a device partitioned by a predetermined dividing line on the front surface, a grinding means for grinding the back surface of the wafer, and a thickness of the wafer. Thickness measuring means to measure in a non-contact, and a data processing means for processing the data obtained by the thickness measuring means, a grinding device comprising:
The holding means,
A holding table for holding the front surface of the wafer protected by the protection member with the back surface of the wafer facing up, a rotating means for rotating the holding table around the center of the holding table, and the holding table for rotating the rotating means Angle recognition unit that recognizes the rotation angle of
The thickness measuring means,
A light projecting unit for projecting measuring light from above the wafer held by the holding table, and a light receiving unit for receiving the reflected light of the measuring light reflected by the wafer; A thickness measuring instrument for measuring the thickness of the wafer from the optical path difference between the reflected light and the reflected light reflected on the surface of the wafer, a moving means for moving the thickness measuring instrument at least in the radial direction of the wafer, A radial position recognition unit that recognizes the position,
The data processing means includes:
The mark formed on the wafer is determined based on the rotation angle of the holding table recognized by the angle recognition unit at the measurement point measured by the thickness measurement device and the radial position of the thickness measurement device recognized by the radial position recognition unit. A calculating unit that calculates the position data of the wafer in the plane direction for the measurement point, and associates the position data calculated by the calculation unit with the thickness value of the chip at each measurement point measured by the thickness measuring device. A grinding unit, comprising: a storage unit that stores and stores the position data and the thickness value of the chip associated with each other in the storage unit to a processing device to be used after the dividing step.

Images