TWI838595B - Grinding device - Google Patents

Abstract

[Topic] In a grinding device, grinding of all wafers in a cassette is completed without replacing the grinding stone. [Solution] A grinding device comprises: a processing condition setting unit for setting processing conditions including grinding stone type and grinding feed speed; consumption data indicating the consumption of the grinding stone when grinding one wafer under the set processing conditions; a wafer number setting unit for setting the number of wafers stored in the cassette; and a cumulative consumption calculation unit for referring to the consumption data and calculating the cumulative consumption of the grinding stone when grinding all the wafers stored in the cassette by a formula. The formula is: the grinding stone consumption of each wafer × the number of wafers set in the wafer number setting unit; the remaining amount identification unit identifies the remaining amount of the grinding stone; and the judgment notification unit, before the start of processing, if the value obtained by deducting the calculated cumulative consumption from the identified remaining amount of the grinding stone has become below the allowable value of the remaining amount of the grinding stone, it is judged that the grinding stone will be consumed before the grinding of all the wafers in the cassette is completed and a notification is made.

Description

Grinding device

The present invention relates to a grinding device for grinding a wafer using a grinding stone.

In a grinding device that grinds a wafer held in a holding mechanism with a grinding stone, the grinding stone is worn out by grinding the wafer, so before the grinding stone is worn out, even during actual operation, the operator is notified to replace the grinding stone. And after the notification, the operator replaces the grinding stone with a new grinding stone.

As disclosed in Patent Document 1, for example, during grinding, the device recognizes the remaining amount of the grinding stone in a sequential and real-time manner, and further, when grinding each wafer, after deducting the grinding stone consumption calculated from the height of the grinding mechanism at the end of grinding from the remaining amount of the grinding stone, the above notification is made if the remaining amount of the grinding stone becomes smaller than a pre-set limit value. Prior Art Documents Patent Documents

Patent document 1: Japanese Patent Application Publication No. 2015-036170

Invention Problems to be Solved

In the grinding device, for example, 25 wafers are stored in a wafer cassette, and the wafers are taken out from the cassette one by one and ground continuously. Therefore, if the above notification is issued when, for example, 5 wafers are ground, the grinding stone will be replaced in the middle of grinding 25 wafers.

Furthermore, when the grinding stone is replaced, the grinding stone in the processing chamber temporarily stops rotating, or the processing chamber is released to the outside air, which causes a change in the temperature in the processing chamber. This temperature change sometimes causes the thickness of the ground wafer to be different for each wafer before and after the grinding stone is replaced. Based on this, there is the following problem: In a grinding device that grinds wafers with a grinding stone, the grinding process of all wafers in a wafer cassette is completed without replacing the grinding stone. Means for solving the problem

The present invention for solving the above-mentioned problem is a grinding device, which comprises: a holding mechanism for holding a wafer by a holding surface; a grinding mechanism for installing a grinding grindstone and grinding the wafer held by the holding mechanism; a grinding feed mechanism for grinding and feeding the grinding mechanism and the holding mechanism relative to each other in a direction perpendicular to the holding surface; a cassette carrier for carrying a cassette that can accommodate a plurality of wafers; and a conveying mechanism for conveying wafers between the cassette and the holding mechanism, wherein the aforementioned grinding device grinds the wafers accommodated in the cassette with the grinding grindstone, and comprises: a processing condition setting unit for setting processing conditions including at least the type of the grinding grindstone and the feed speed of the grinding feed mechanism in order to grind the wafer with the grinding grindstone; a consumption data indicating the consumption of the grinding grindstone when grinding a wafer with the set processing conditions. The consumption of the grinding stone; The wafer number setting unit sets the number of wafers stored in the wafer cassette; The cumulative consumption calculation unit refers to the consumption data and uses a formula to calculate the cumulative consumption of the grinding stone when all the wafers stored in the wafer cassette are ground, wherein the above formula is: the consumption of the grinding stone for each wafer × the number of wafers set in the wafer number setting unit; The remaining amount An identification unit that identifies the remaining amount of the grinding stone; and a judgment notification unit that, before the start of processing, if the value obtained by deducting the accumulated consumption calculated by the accumulated consumption calculation unit from the remaining amount of the grinding stone identified by the remaining amount identification unit is below the allowable value of the remaining amount of the grinding stone, it is determined that the grinding stone will be consumed before the grinding of all the wafers in the wafer cassette is completed, and a notification is made. Effect of the invention

In the past, there were times when a notice to replace the grinding stone was issued during grinding, but the following situation occurred: multiple wafers stored in the cassette could not be ground with the same grinding stone and at roughly the same processing room temperature. As a result, the following situation occurred: the thickness of multiple wafers after grinding was uneven. However, the grinding device of the present invention comprises: a processing condition setting unit for setting processing conditions including at least the type of grinding stone and the feed speed of the grinding feed mechanism for grinding wafers using a grinding stone; consumption data indicating the consumption of the grinding stone when grinding one wafer with the set processing conditions; a wafer number setting unit for setting the number of wafers stored in the wafer cassette; a cumulative consumption calculation unit for referring to the consumption data and calculating the cumulative consumption of the grinding stone when all the wafers stored in the wafer cassette are ground by a formula, wherein the formula is: the consumption of the grinding stone for each wafer × the number of wafers set in the wafer number setting unit; a remaining amount identification unit for identifying the remaining amount of the grinding stone; and a judgment unit for determining whether the wafers stored in the wafer cassette are fully consumed. The notification unit determines that the grinding stone will be used up before the grinding of all the wafers in the cassette is completed, and makes a notification before the start of the processing. If the value obtained by deducting the accumulated consumption calculated by the accumulated consumption calculation unit from the accumulated consumption of the grinding stone identified by the accumulated consumption identification unit becomes below the allowable value of the accumulated consumption of the grinding stone before the processing starts, the notification unit makes a notification. Thus, before the start of the grinding processing, the operator can be notified that the grinding stone must be replaced before the grinding of all the wafers accommodated in the cassette is completed. Therefore, when the notification is given, the operator can replace the grinding stone before the grinding processing and start the grinding processing thereafter, so that the processing results including thickness of the multiple wafers being processed can be made more uniform.

The form used to implement the invention

The grinding device 1 shown in FIG. 1 is a device for grinding a wafer W held by a holding mechanism 30 by a grinding mechanism 4. The front (-Y direction side) on the base 10 of the grinding device 1 is an area for carrying in and out the wafer W from the holding mechanism 30, namely, a carrying-in and carrying-out area A, and the rear (+Y direction side) on the base 10 is an area for grinding the wafer W held by the holding mechanism 30 by the grinding mechanism 4, namely, a processing area B. Furthermore, the grinding device of the present invention can also be formed as follows: a double axis having a rough grinding mechanism and a fine grinding mechanism as a grinding mechanism, and a rotating turntable is used to position the holding mechanism 30 holding the wafer W below each grinding mechanism.

The wafer W shown in FIG. 1 is a circular semiconductor wafer made of silicon mother material in this embodiment, and a plurality of devices are formed on the front surface Wa of the wafer W facing downward in FIG. 1 and is protected by a protective tape not shown. The back surface Wb of the wafer W facing upward is the processed surface for grinding. In addition, the wafer W can also be made of gallium arsenide, sapphire, gallium nitride, resin, ceramic or silicon carbide, etc., in addition to silicon.

A first cassette carrier 150 and a second cassette carrier 151 are disposed on the front side (-Y direction side) of the base 10. The first cassette carrier 150a for storing a plurality of wafers W before processing in a shelf form can be placed on the first cassette carrier 150, and the second cassette carrier 151a for storing a plurality of wafers W after processing in a shelf form can be placed on the second cassette carrier 151.

Behind the opening on the +Y direction side of the first cassette 150a, a robot 155 is provided that can carry out the wafer W before processing from the first cassette 150a and carry the wafer W after processing into the second cassette 151a. A temporary area 152 is provided adjacent to the robot 155, and a positioning mechanism 153 is provided in the temporary area 152. The positioning mechanism 153 is to align the wafer W carried out from the first cassette 150a and placed in the temporary area 152 to a predetermined position (centering) by using a reduced diameter positioning pin.

A loading arm 154a is disposed adjacent to the alignment mechanism 153 and rotates while holding the wafer W. The loading arm 154a holds the wafer W aligned in the alignment mechanism 153 and transfers it to the holding mechanism 30 disposed in the processing area B. An unloading arm 154b is disposed next to the loading arm 154a and rotates while holding the processed wafer W. A single-piece cleaning mechanism 156 is disposed adjacent to the unloading arm 154b and cleans the processed wafer W transferred by the unloading arm 154b. The wafer W cleaned and dried by the cleaning mechanism 156 is transferred to the second wafer cassette 151a by the robot 155.

In the present embodiment, the robot 155 , the loading arm 154 a , and the unloading arm 154 b constitute a transfer mechanism for transferring the wafer W between the first cassette 150 a and the second cassette 151 a and the holding mechanism 30 .

The holding mechanism 30 disposed on the base 10 of the grinding device 1 and holding the wafer W is, for example, circular in plan view and has a holding surface 30a, which is connected to a suction source (not shown) and is composed of a porous member or the like and can suck and hold the wafer W. The holding mechanism 30 is surrounded by a cover 39 and can reciprocate in the Y-axis direction on the base 10 by a Y-axis direction feed mechanism (not shown). The Y-axis direction feed mechanism is disposed under the cover 39 and a bellows cover 39a connected to the cover 39. The holding mechanism 30 is rotatable around a rotation axis in the Z-axis direction.

A support column 12 is vertically arranged at the rear (+Y direction side) of the processing area B, and a grinding feed mechanism 2 is arranged on the front surface of the support column 12 on the -Y direction side. The grinding feed mechanism 2 grinds and feeds the grinding mechanism 4 and the holding mechanism 30 relative to each other in the Z-axis direction (lead vertical direction) perpendicular to the holding surface 30a. The grinding feed mechanism 2 includes a ball screw 20 having an axis in the Z-axis direction, a pair of guide rails 21 arranged parallel to the ball screw 20, a motor 22 connected to the upper end of the ball screw 20 and causing the ball screw 20 to rotate, a lifting plate 23 whose inner nut is screwed to the ball screw 20 and whose side is slidably connected to the guide rails 21, and a retainer 24 connected to the lifting plate 23 and retaining the grinding mechanism 4. When the motor 22 causes the ball screw 20 to rotate, the lifting plate 23 is guided by the guide rails 21 and moves back and forth in the Z-axis direction, thereby grinding and feeding the grinding mechanism 4 retained on the retainer 24 in the Z-axis direction.

The grinding mechanism 4 for grinding the wafer W held on the holding mechanism 30 has a rotating shaft 40 whose axial direction is the Z-axis direction, a housing 41 that supports the rotating shaft 40 so that it can rotate, a motor 42 that rotationally drives the rotating shaft 40, an annular mounting seat 43 connected to the lower end of the rotating shaft 40, and a grinding wheel 44 that is detachably mounted on the lower surface of the mounting seat 43.

The grinding wheel 44 includes a wheel base 441 and a plurality of substantially rectangular parallelepiped grinding stones 440 disposed in a ring shape on the bottom surface of the wheel base 441. The grinding stones 440 are formed by fixing grinding abrasive grains with a predetermined adhesive or the like.

A flow path (not shown) for passing grinding water is formed inside the rotating shaft 40 in the axial direction (Z-axis direction) of the rotating shaft 40. This flow path passes through the mounting seat 43 and opens at the bottom surface of the wheel base 441 in a manner that the grinding water can be sprayed toward the grinding grindstone 440.

A thickness measuring mechanism 38 is provided near the grinding wheel 44 which has descended to the height position when grinding the wafer W. The thickness measuring mechanism 38 measures the thickness of the wafer W by contact, for example, during grinding. The thickness measuring mechanism 38 includes, for example, a pair of thickness measuring devices (height gauges), a first thickness measuring device 381 for measuring the height position of the holding surface 30a of the holding mechanism 30, and a second thickness measuring device 382 for measuring the height position of the back surface Wb, which is the ground surface, of the wafer W held by the holding mechanism 30.

The first thickness gauge 381 and the second thickness gauge 382 have contacts at their respective front ends that are lifted and lowered in the up-and-down direction and contact the respective measuring surfaces. The first thickness gauge 381 (the second thickness gauge 382) is supported in a manner that allows it to move up and down, and is formed so that it can press the respective measuring surfaces with an appropriate force. The thickness measuring mechanism 38 detects the height position of the holding surface 30a, which is the reference surface, by the first thickness gauge 381, and detects the height position of the back surface Wb, which is the upper surface of the ground wafer W, by the second thickness gauge 382, and calculates the difference between the detection values of the two, thereby sequentially measuring the thickness of the wafer W during grinding. Furthermore, the thickness measuring mechanism 38 can also be a non-contact thickness measuring mechanism.

The grinding device 1 has a control mechanism 9 for controlling the entire device. The control mechanism 9 is composed of a CPU and a storage medium such as a memory that perform calculations according to a control program, and is electrically connected to an unillustrated Y-axis feed mechanism that moves the holding mechanism 30 in the Y-axis direction, and a grinding mechanism 4, etc. through an unillustrated wired or wireless communication path. Under the control of the control mechanism 9, the Y-axis movement control of the holding mechanism 30 that attracts and holds the wafer W, the positioning control of the grinding mechanism 4, and the rotational movement of the grinding wheel 44 in the grinding mechanism 4 can be controlled.

For example, the control mechanism 9 can be electrically connected to the motor 22 of the grinding feed mechanism 2 that moves the grinding mechanism 4 up and down. For example, when the motor 22 is a servo motor, the rotary encoder of the servo motor is connected to the control mechanism 9 that also functions as a servo amplifier, and after supplying an action signal to the servo motor from the output interface of the control mechanism 9, the number of rotations of the servo motor can be output as a coded signal to the input interface of the control mechanism 9. In addition, the control mechanism 9 that has received the coded signal can sequentially identify the movement amount of the grinding mechanism 4 according to the rotation angle of the servo motor, and thereby sequentially identify the height position of the grinding mechanism 4.

For example, the grinding device 1 has a touch panel 16 (or a keyboard of an accessory device, etc.) as an input mechanism for allowing an operator to input processing conditions, etc. to the grinding device 1. For example, the touch panel 16 is electrically connected to the control mechanism 9, and detects the position touched by the operator's finger, and sends a signal indicating the detection result to the control mechanism 9. On the touch panel 16, an input screen and a display screen can be displayed, and the operator can input various information of processing conditions, etc. and set them in the grinding device 1 through the input screen, and various information of processing conditions, etc., the state of the ground back surface Wb of the wafer W, and the state of each part of the device can be displayed through the display screen.

The grinding device 1 comprises: a processing condition setting unit 91 for setting processing conditions including at least the type of the grinding stone 440 and the feed speed of the grinding feed mechanism 2 for grinding the wafer W using the grinding stone 440; consumption data 93 for indicating the consumption of the grinding stone 440 when grinding one wafer W under the set processing conditions; a wafer number setting unit 95 for setting the number of wafers W before processing stored in the first wafer cassette 150a; and a cumulative consumption calculation unit 96 for referring to the consumption data 93 and calculating the cumulative consumption of the grinding stone 440 when all the wafers W stored in the first wafer cassette 150a are ground by a formula, wherein the aforementioned formula is: [consumption of the grinding stone 440 for each wafer W] × [the number of wafers W set in the wafer number setting unit 95]. Furthermore, in addition to the operator inputting the number of wafers W before processing stored in the first wafer box 150a as described above into the wafer number setting unit 95, a sensor for detecting the wafers W stored in the first wafer box 150a is also provided, and the number of wafers W stored in the first wafer box 150a is detected by detecting the wafers W with the sensor, and further set it in the wafer number setting unit 95.

In the present embodiment, the processing condition setting section 91 is provided in an area of the memory medium of the control mechanism 9, and when, for example, the operator inputs at least the type determined by the combination of the abrasive grains (e.g., diamond abrasive grains, etc.) of the grinding stone 440 and the adhesive (e.g., resin, metal, or ceramic (vitrified), etc.), and the grinding feed speed of the grinding mechanism 4 performed by the grinding feed mechanism 2 as a part of the processing conditions into the unillustrated touch panel 16, the processing conditions can be set (stored) in the processing condition setting section 91. Furthermore, the rotation speed of the grinding wheel 44, the rotation speed of the holding mechanism 30 holding the wafer W, the type of the wafer W, the finished thickness of the wafer W, etc. can also be included as a part of the processing conditions set in the processing condition setting section 91.

In this embodiment, consumption data 93 is data stored in an area of a storage medium of the control mechanism 9. Consumption data 93 is data obtained, for example, in past experiments. The following describes an example of a situation in which consumption data 93 can be obtained.

In the processing conditions set in the processing condition setting section 91 of the grinding device 1, the type of the grinding stone 440 is type 1, and the grinding feed speed of the grinding mechanism 4 performed by the grinding feed mechanism 2 is set to the grinding feed speed V1. For example, the thickness of the first wafer W to be ground in the grinding device 1 before grinding is 300 μm, and the finished thickness of the wafer W is set to 100 μm.

As shown in FIG. 2 , the holding mechanism 30 holding the wafer W is moved under the grinding mechanism 4, and the holding mechanism 30 is positioned so that the rotation center of the grinding wheel 44 of the grinding mechanism 4 is horizontally offset from the rotation center of the wafer W by a predetermined distance, and the rotation trajectory of the grinding wheel 44 passes through the rotation center of the wafer W.

Afterwards, under the control of the control mechanism 9 shown in FIG. 1 , the motor 22 of the grinding feed mechanism 2 is driven to gradually lower the grinding mechanism 4 from the predetermined origin height position known in advance as shown in FIG. 2 at a predetermined speed. Moreover, the height position of the grinding mechanism 4 that has begun to descend can be controlled at any time by the control mechanism 9. During the grinding process, the thickness of the wafer W is measured in real time and in sequence by the thickness measuring mechanism 38. The measurement result is transmitted to the control mechanism 9 shown in FIG. 1 , and the grinding feed amount of the grinding mechanism 4 formed by the motor 22 is controlled to be close to the target finished product thickness, and the first wafer W is ground to the finished product thickness (100 μm).

Regarding the consumption of the grinding stone 440, the control mechanism 9 identifies the grinding amount of the wafer W from the difference between the thickness of the wafer W before grinding and the thickness of the wafer W after grinding, and can further make the control mechanism 9 identify the grinding feed amount (descent amount) of the grinding mechanism 4 from the height position Z0 when the grinding stone 440 contacts the back side Wb of the wafer W (that is, the difference between the height position Z0 of the grinding mechanism 4 before grinding and the height position Z1 of the grinding mechanism 4 at the end of grinding), and calculate it as: [grinding feed amount of the grinding mechanism 4]-[grinding amount of the wafer W measured by the thickness measuring mechanism 38]=[consumption of the grinding stone 440]. For example, the initial consumption of the grinding stone 440 when the first wafer W has been ground to the finished product thickness is set to the consumption L1. The consumption L1 is basically not adopted as the consumption data 93 because the grinding process performed on the first wafer W is not stable or more set-up errors are generated.

Next, the grinding process of the second wafer W shown in FIG. 3 is performed in the same manner as described above, and the wafer W is ground to a finished product thickness of 100 μm, and the height position Z2 of the grinding mechanism 4 at the end of the grinding is identified, and the consumption L2 of the grinding stone 440 shown in FIG. 3 is calculated. Because the grinding process of the second wafer W is performed stably and no setting error or the like is generated, the consumption L2 becomes the consumption of the grinding stone 440 when one wafer W is ground under the set processing conditions (that is, at least the type of the grinding stone 440 is type 1, and the grinding feed speed of the grinding mechanism 4 performed by the grinding feed mechanism 2 is the grinding feed speed V1) (consumption data 93). Furthermore, a plurality of wafers W may be further ground to calculate the consumption of the grinding stone 440 for each wafer, and the average of the plurality of consumptions may be determined as the consumption data 93. In addition, the difference between the height position of the grinding mechanism 4 when the first wafer W is ground to the finished product thickness and the height position of the grinding mechanism 4 when the second wafer W is ground to the finished product thickness may be set as the consumption of the grinding stone 440 when one wafer W is ground (consumption data 93).

The grinding device 1 may include, in addition to the consumption data 93 obtained as described above, a plurality of consumption data different for each processing condition in the control mechanism 9 .

As shown in Fig. 1, the grinding device 1 has a remaining amount identification unit 92 for identifying the remaining amount of the grinding stone 440. The remaining amount identification unit 92 is incorporated in, for example, the control mechanism 9. The remaining amount identification unit 92 is electrically connected to the grinding stone remaining amount detection mechanism 35 shown in Fig. 1 through a wired or wireless communication path.

The non-contact type grinding stone remaining amount detection mechanism 35 is disposed on, for example, a cover 39 surrounding the holding mechanism 30, and the grinding stone remaining amount detection mechanism 35 is reciprocated in the Y-axis direction together with the holding mechanism 30 and the cover 39 that can reciprocate in the Y-axis direction by a Y-axis direction feed mechanism (not shown). The arrangement position of the grinding stone remaining amount detection mechanism 35 is not limited to being disposed on the cover 39 as long as it is located below the grinding mechanism 4, and may also be formed to be movable.

The grinding stone remaining amount detection mechanism 35 is, for example, a reflective type (diffused reflective type or limited reflective type, etc.) photoelectric sensor, and the light projecting part 350 and the light receiving part 351 are built into one sensing amplifier. Furthermore, a shielding plate (not shown) may be provided between the holding mechanism 30 and the grinding stone remaining amount detection mechanism 35, and the shielding plate prevents grinding chips, etc. from entering the grinding stone remaining amount detection mechanism 35 from the holding mechanism 30 side.

The following describes the operation of each component of the grinding device 1 when the grinding device 1 grinds the wafer W. First, for example, the operator selects a processing condition for the wafer W to be processed next from a plurality of processing conditions displayed on the input screen of the touch panel 16, and inputs it to the control mechanism 9. The selected processing condition is at least a processing condition in which the type of the grinding stone 440 is set to type 1 and the grinding feed speed of the grinding mechanism 4 performed by the grinding feed mechanism 2 is the grinding feed speed V1. The selected processing condition is set in the processing condition setting unit 91.

Furthermore, the operator inputs the number of wafers W before grinding that have been stored in the first cassette 150a to the control mechanism 9 from the input screen of the touch panel 16. Furthermore, the number of wafers W can also be set so that the grinding device 1 automatically grasps the number of wafers W that have been loaded in the first cassette 150a of the first cassette carrier 150 by means of a sensor or the like. The number of wafers W is set to, for example, 25. Then, the number of wafers W, 25, can be set to the wafer number setting unit 95.

The accumulated consumption calculation unit 96 incorporated in the control mechanism 9 refers to the consumption data 93 stored in the storage medium of the control mechanism 9 to calculate [the consumption of the grinding stone 440 for each wafer W] × [the number of wafers W set in the wafer number setting unit 95] = [the consumption L2 shown in FIG. 3] × 25 = the accumulated consumption L9 of the grinding stone 440 when all 25 wafers W stored in the first wafer box 150a are ground.

Furthermore, the remaining amount of the grinding stone 440 mounted on the grinding mechanism 4 can be identified by the grinding stone remaining amount detection mechanism 35 and the remaining amount identification unit 92. This remaining amount identification can be performed, for example, during the warm-up operation before the grinding device 1 starts processing. In this remaining amount identification, first, the grinding stone remaining amount detection mechanism 35, which moves together with the holding mechanism 30, is positioned directly below the lower surface of the grinding stone 440 of the grinding mechanism 4 at an arbitrary height position Z3 shown in FIG. 4 by the Y-axis direction feeding mechanism (not shown). Then, the light projection unit 350 of the grinding stone remaining amount detection mechanism 35 irradiates the measurement light toward the lower surface of the grinding stone 440. Then, the distance in the Z-axis direction from the grinding stone remaining amount detection mechanism 35 to the lower surface of the grinding stone 440 can be measured based on the optical triangulation distance measurement principle by receiving the measurement light reflected on the lower surface of the grinding stone 440 with the light receiving unit 351 composed of CCD or the like. The distance is, for example, the distance La. The information on the distance La can be transmitted from the grinding stone remaining amount detection mechanism 35 to the control mechanism 9 and stored in the control mechanism 9.

Next, the grinding stone remaining amount detection mechanism 35 is positioned directly below the lower surface of the wheel base 441 of the grinding mechanism 4 by means of the Y-axis direction feed mechanism (not shown). Furthermore, the height position Z3 of the grinding mechanism 4 is maintained. Then, the light projection unit 350 of the grinding stone remaining amount detection mechanism 35 irradiates the measurement light toward the lower surface of the wheel base 441. Then, the distance Lc in the Z-axis direction from the grinding stone remaining amount detection mechanism 35 to the lower surface of the wheel base 441 can be measured by receiving the measurement light reflected on the lower surface of the wheel base 441 by the light receiving unit 351. Information about the distance Lc is transmitted from the grinding stone remaining amount detection mechanism 35 to the control mechanism 9 and stored in the control mechanism 9.

The remaining amount recognition unit 92 incorporated in the control mechanism 9 recognizes the value obtained by subtracting the distance La from the distance Lc as the remaining amount of the grinding stone 440. For example, [distance Lc] - [distance La] = remaining amount Ld of the grinding stone 440.

The identification of the remaining amount of the grinding stone 440 is not limited to the above-mentioned embodiment. For example, the grinding device 1 may also have a contact type grinding stone remaining amount detection mechanism 36 shown in FIG. 6 instead of the grinding stone remaining amount detection mechanism 35. The grinding stone remaining amount detection mechanism 36 includes, for example, a contacted lifting part 365 that contacts the lower surface of the grinding stone 440 or the lower surface of the wheel base 441 and can be raised and lowered, a housing 360 that accommodates the contacted lifting part 365 in a manner that allows it to be raised and lowered in the Z-axis direction, an elastic member 364 such as a spring disposed on the inner bottom surface of the housing 360 and supporting the contacted lifting part 365 so that it can be raised and lowered, and a transmission type photo sensor that detects when the lower surface of the grinding stone 440 or the lower surface of the wheel base 441 that is lowered by the grinding feed mechanism 2 contacts the contacted lifting part 365 and the contacted lifting part 365 starts to descend. For example, the grinding stone remaining amount detection mechanism 36 can send various detection signals to the control mechanism 9 shown in FIG. 1 through a wireless or wired communication path (not shown).

The transmission type photo sensor for detecting that the lower surface of the lower grinding stone 440 or the lower surface of the wheel base 441 starts to descend by contacting the contacted lifting part 365 includes a light projecting part 362 and a light receiving part 363 disposed on the inner side surface of the side wall of the housing 360 and facing each other in the Y-axis direction. As the contacted lifting part 365 descends, the measurement light projected by the light projecting part 362 is shielded, and the light receiving part 363 detects a decrease in the amount of light received, thereby detecting that the lower surface of the grinding stone 440 or the lower surface of the wheel base 441 has contacted the contacted lifting part 365. Furthermore, the grinding stone remaining amount detection mechanism 36 is not limited to a transmission type photo sensor, but can also be an electrostatic capacitance type proximity sensor, or a pressure sensor disposed on the upper surface of the contacted lifting part 365 to directly detect the lower surface of the contacted grinding stone 440 or the lower surface of the wheel base 441.

The identification of the remaining amount of the grinding stone 440 is explained by the grinding stone remaining amount detection mechanism 36 and the remaining amount identification unit 92 shown in FIG6. The grinding stone remaining amount detection mechanism 36, which moves together with the holding mechanism 30, can be positioned directly below the lower surface of the grinding stone 440 of the grinding mechanism 4 by the Y-axis direction feed mechanism not shown. Then, under the control of the control mechanism 9, the grinding feed mechanism 2 gradually lowers the grinding mechanism 4, which has been positioned at a height position known in advance, at a predetermined speed. In addition, the height position of the grinding mechanism 4 that has begun to descend can be known at any time by the control mechanism 9.

For example, as shown in FIG6 , the lower surface of the grinding stone 440 of the descending grinding mechanism 4 contacts the upper surface of the contacted lifting part 365, causing the contacted lifting part 365 to start descending, and the light receiving part 363 of the transmission type photo sensor detects the reduction of the measurement light. The detection signal is sent from the grinding stone remaining amount detection mechanism 36 to the control mechanism 9, and under the control of the control mechanism 9, the grinding feed of the grinding mechanism 4 in the -Z direction by the grinding feed mechanism 2 is stopped. In addition, the control mechanism 9 memorizes the height position of the grinding mechanism 4 at the time point when the lower surface of the grinding stone 440 contacts the upper surface of the contacted lifting part 365. This height position is, for example, the height position Z4 shown in FIG6 .

Next, as shown in FIG7 , the grinding stone remaining amount detection mechanism 36 is positioned directly below the lower surface of the wheel base 441 of the grinding mechanism 4 by the Y-axis direction feed mechanism (not shown). Then, under the control of the control mechanism 9, the grinding feed mechanism 2 causes the grinding mechanism 4, which has been positioned at a predetermined height position, to gradually descend at a predetermined speed.

For example, as shown in FIG7 , the lower surface of the wheel base 441 of the descending grinding mechanism 4 contacts the upper surface of the contacted lifting part 365, and the light receiving part 363 of the photo sensor detects the reduction of the measurement light. The detection signal is sent from the grinding stone remaining amount detection mechanism 36 to the control mechanism 9, and under the control of the control mechanism 9, the grinding feed of the grinding mechanism 4 in the -Z direction is stopped. In addition, the control mechanism 9 recognizes the height position Z5 of the grinding mechanism 4 at the time point when the lower surface of the wheel base 441 contacts the upper surface of the contacted lifting part 365.

The remaining amount recognition unit 92 incorporated in the control mechanism 9 shown in Fig. 1 recognizes the value obtained by subtracting the height position Z5 from the height position Z4 shown in Fig. 7 as the remaining amount Ld of the grinding stone 440. For example, [height position Z4] - [height position Z5] = the remaining amount Ld of the grinding stone 440.

The grinding device 1 is provided with a judgment notification unit 99 shown in FIG1 . The judgment notification unit 99 is incorporated into the control mechanism 9 in the present embodiment. Before the start of machining, the judgment notification unit 99 calculates a value L10 obtained by deducting the accumulated consumption L9 calculated by the accumulated consumption calculation unit 96 as described above from the remaining amount Ld of the grinding stone 440 identified by the remaining amount identification unit 92 .

In addition, the judgment notification unit 99 judges whether the calculated value L10 is below the allowable value of the remaining amount of the grinding stone (for example, 0 μm) or exceeds the allowable value of the remaining amount of the grinding stone. For example, the value L10 has become below 0 μm. In this case, it is judged that the grinding stone 440 will be used up before the grinding of all 25 wafers W in the first wafer cassette 150a is completed, and the judgment can be displayed on the touch panel 16 or announced by a speaker not shown in the figure, and the judgment can be notified to the operator. In this case, the operator who has recognized the judgment will replace the grinding wheel 44 with a remaining amount Ld of the grinding stone 440 installed in the grinding mechanism 4 with a new grinding wheel 44 before starting the grinding process of the wafer W. Furthermore, it can also be arranged that: when the allowable value of the remaining amount of the grinding stone 440 is preset to, for example, several μm, and before the start of processing, when the value L10 obtained by deducting the accumulated consumption L9 calculated by the accumulated consumption calculation unit 96 as previously described from the remaining amount Ld of the grinding stone 440 identified by the remaining amount identification unit 92 becomes below the allowable value of the remaining amount of the grinding stone, the judgment notification unit 99 will notify the operator of the following: the grinding wheel 44 currently installed in the grinding mechanism 4 is not suitable for grinding all 25 wafers W.

Furthermore, when, for example, the value L10 exceeds the allowable value of the remaining grinding stone (e.g., 0 μm), it is determined that the type 1 grinding stone 440 will not be used up before the grinding of all 25 wafers W in the first cassette 150a shown in FIG. 1 is completed, and in the present embodiment, for example, in the fully automatic grinding device 1, a wafer W is moved out of the first cassette 150a by the robot 155 in order to start the grinding process of the wafer W. Furthermore, the allowable value of the remaining grinding stone can be set to an integer including 0.

When the grinding wheel 44 is replaced with a new grinding wheel and the grinding of the wafer W shown in FIG. 1 is started, the holding mechanism 30 is moved to the vicinity of the loading arm 154 a. The robot 155 pulls out a wafer W from the first cassette 150 a and moves the wafer W to the temporary area 152 .

After the wafer W is centered by the alignment mechanism 153 on the temporary area 152, the loading arm 154a transfers the centered wafer W to the holding mechanism 30. Then, the suction source (not shown) is activated to allow the holding mechanism 30 to suck and hold the wafer W on the holding surface 30a with the back side Wb exposed upward.

Next, the holding mechanism 30 shown in FIG. 1 holding the wafer W is moved in the +Y direction to the bottom of the grinding mechanism 4. The grinding mechanism 4 is fed in the -Z direction at a grinding feed speed V1 by the grinding feed mechanism 2, and the grinding stone 440 of type 1 of the grinding wheel 44 that rotates along with the rotation of the rotating shaft 40 abuts against the back surface Wb of the wafer W for grinding. During grinding, since the wafer W held on the holding surface 30a also rotates along with the rotation of the holding mechanism 30, the grinding wheel 44 can grind the entire back surface Wb of the wafer W. In addition, by supplying grinding water to the contact portion between the grinding stone and the wafer W to cool the contact portion, the grinding chips generated at the contact portion can be cleaned and removed.

After the wafer W is ground to a desired thickness (e.g., 100 μm), the grinding mechanism 4 is raised by the grinding feed mechanism 2 to separate it from the wafer W, and the holding mechanism 30 is further moved in the -Y direction to be positioned near the unloading arm 154b. Then, the wafer W whose back side Wb is held by the unloading arm 154b is transported to the cleaning mechanism 156. The back side Wb of the wafer W is rotated and cleaned by the cleaning mechanism 156, and after further drying, it is moved into the second wafer cassette 151a by the robot 155.

The 25 wafers W stored in the first cassette 150 a are subjected to the grinding process described above in sequence, and the grinding process of all the wafers W in the first cassette 150 a is completed.

As described above, the grinding device 1 of the present invention comprises: a processing condition setting unit 91 for setting processing conditions including at least the type of the grinding stone 440 and the feed speed of the grinding feed mechanism 2 for grinding the wafer W using the grinding stone 440; a consumption data 93 for indicating the consumption of the grinding stone 440 when grinding one wafer W under the set processing conditions; a wafer number setting unit 95 for setting the number of wafers stored in the first wafer cassette 150a; W; a cumulative consumption calculation unit 96, referring to the consumption data 93, and using a formula to calculate the cumulative consumption of the grinding stone 440 when all the wafers W stored in the first wafer cassette 150a are ground, wherein the formula is: the consumption of the grinding stone 440 for each wafer W × the number of wafers W set in the wafer number setting unit 95; a remaining quantity identification unit 92, identifying the remaining quantity of the grinding stone 440; and a judgment notification unit 99 Before the processing starts, if the value obtained by deducting the accumulated consumption calculated by the accumulated consumption calculation unit 96 from the remaining amount of the grinding stone 440 identified by the remaining amount identification unit 92 is below the allowable value of the grinding stone remaining amount, it is determined that the grinding stone 440 will be consumed before the grinding of all the wafers W in the first wafer box 150a is completed, and a notification is made. In this way, the operator can be notified before the grinding process starts that there will be a need to grind the grinding stone 440 in the first wafer box 150a. The grinding stone 440 is replaced before the grinding process of all the wafers W accommodated in the first wafer box 150a is completed. Therefore, when a notification is given, the operator can replace the grinding stone 440 with a new grinding stone 440 that can grind all the wafers W in the first wafer box 150a before the grinding process, and then perform the grinding process. Therefore, the processing results including thickness of the multiple wafers W to be processed can be made more uniform.

Furthermore, the grinding device 1 of the present invention is not limited to the device of the above-mentioned embodiment, and the various structures shown in the attached drawings are not limited thereto, and can be appropriately modified within the scope that can exert the effects of the present invention.

For example, the calculation of the consumption of the grinding stone 440 when grinding a wafer W under the set processing conditions is not limited to the example of calculation as described previously. For example, the remaining amount of the grinding stone 440 before grinding a wafer W can be measured by the remaining amount detection mechanism 36 and the remaining amount identification unit 92, and the remaining amount of the grinding stone 440 after grinding a wafer W can be further measured, and the difference between the remaining amounts of the grinding stone before and after grinding can be calculated to obtain the consumption.

For example, in the present embodiment, although the grinding process of wafer W is performed under the same processing conditions as those used in the past to grind wafer W, in the case where the grinding process of wafer W is performed under processing conditions that have not been performed in the past, wafer W or a dummy wafer is used, and new processing conditions are set in the processing condition setting unit 91 before the grinding process starts to conduct a processing experiment, and the consumption data of the obtained results are re-stored in the control mechanism 9.

1: Grinding device 10: Base 12: Pillar 150: 1st magazine carrier 150a: 1st magazine 151: 2nd magazine carrier 151a: 2nd magazine 152: Temporary area 153: Alignment mechanism 154a: Loading arm 154b: Unloading arm 155: Robot 156: Cleaning mechanism 16: Touch panel 2: Grinding feed mechanism 20: Ball screw 21: Guide rail 22: Motor 23: Lifting plate 24: Holder 30: Holding mechanism 30a: Holding surface 35: Grinding stone remaining amount detection mechanism 350: Light-emitting part 351: Light-receiving part 36: Grinding stone remaining amount detection mechanism 360: Cover 362: Light-emitting part 363: Light-receiving part 364: Elastic member 365: Contact lifting part 38: Thickness measuring mechanism 381 :1st thickness gauge 382:2nd thickness gauge 39:Cover 39a:Accent cover 4:Grinding mechanism 40:Rotating shaft 41:Casing 42:Motor 43:Mounting seat 44:Grinding wheel 440:Grinding stone 441:Wheel base 9:Control mechanism 91:Processing condition setting unit 92:Remaining quantity identification unit 93:Consumption data 95:Wafer quantity setting unit 96: Cumulative consumption calculation unit 99: Judgment notification unit A: Loading and unloading area B: Processing area L1, L2: Consumption L9: Cumulative consumption L10: Value La, Lc: Distance Ld: Remaining amount W: Wafer Wa: Front Wb: Back Z0, Z1, Z2, Z3, Z4, Z5: Height position X, +X, -X, +Y, -Y, +Z, -Z: Direction

FIG. 1 is a perspective view showing an example of a grinding device. FIG. 2 is a cross-sectional view showing a situation where a first wafer is ground to a finished product thickness. FIG. 3 is a cross-sectional view showing a situation where a second wafer is ground to obtain consumption data. FIG. 4 is a cross-sectional view showing a state where a non-contact type grindstone remaining amount detection mechanism irradiates a measuring light toward the lower surface of the grinding stone in order to identify the remaining amount of the grinding stone by the remaining amount identification unit. FIG. 5 is a cross-sectional view showing a state where a non-contact type grindstone remaining amount detection mechanism irradiates a measuring light toward the lower surface of the wheel base in order to identify the remaining amount of the grinding stone by the remaining amount identification unit. FIG6 is a cross-sectional view showing a state in which the lower surface of the grinding stone is brought into contact with the contact type grinding stone remaining amount detection mechanism in order to identify the remaining amount of the grinding stone by the remaining amount identification unit. FIG7 is a cross-sectional view showing a state in which the lower surface of the wheel base is brought into contact with the contact type grinding stone remaining amount detection mechanism in order to identify the remaining amount of the grinding stone by the remaining amount identification unit.

1: Grinding device

10: Base

12: Pillar

150: 1st film cassette carrier

150a: 1st film box

151: Second cassette carrier

151a: Second film cassette

152: Temporary Area

153: Positioning mechanism

154a: Loading arm

154b: Unloading arm

155:Robot

156: Cleaning mechanism

16: Touch panel

2: Grinding feed mechanism

20:Ball screw

21:Guide rail

22: Motor

23: Lifting plate

24: Retainer

30:Maintaining mechanism

30a: Keep the face

35: Grinding stone remaining amount detection mechanism

350: Lighting unit

351: Light Receiving Department

38: Thickness measurement mechanism

381: 1st thickness measuring device

382: Second thickness measuring device

39: Cover

39a: bellied cover

4: Grinding mechanism

40: Rotation axis

41: Shell

42: Motor

43: Mounting seat

44: Grinding wheel

440: Grinding Stone

441: Wheel base

9: Controlling agency

91: Processing condition setting department

92: Remaining quantity identification unit

93: Consumption data

95: Wafer number setting unit

96: Cumulative consumption calculation unit

99: Judgment Notification Department

A: Move in and move out area

B: Processing area

W: Wafer

Wa: Front

Wb:Back

+X,-X,+Y,-Y,+Z,-Z: Direction

Claims (1)

A grinding device comprises: a holding mechanism for holding a wafer by a holding surface; a grinding mechanism for mounting a grinding stone and grinding the wafer held by the holding mechanism; a grinding feed mechanism for grinding and feeding the grinding mechanism and the holding mechanism relative to each other in a direction perpendicular to the holding surface; a cassette carrier for carrying a cassette that can accommodate a plurality of wafers; and a conveying mechanism for conveying wafers between the cassette and the holding mechanism, wherein the grinding device grinds the wafers accommodated in the cassette with the grinding stone, and comprises: a processing condition setting unit for setting processing conditions for grinding wafers with the grinding stone, which at least include the type of the grinding stone and the feed speed of the grinding feed mechanism; consumption data, indicating the consumption of the grinding stone when grinding a wafer with the set processing conditions ; Wafer number setting unit, sets the number of wafers stored in the wafer cassette; Accumulated consumption calculation unit, refers to the consumption data and uses a formula to calculate the accumulated consumption of the grinding stone when all the wafers stored in the wafer cassette are ground, wherein the aforementioned formula is: the consumption of the grinding stone for each wafer × the number of wafers set in the wafer number setting unit; Remaining quantity identification unit , identifying the remaining amount of the grinding stone; and The judgment and notification unit, before the start of processing, if the value obtained by deducting the accumulated consumption calculated by the accumulated consumption calculation unit from the remaining amount of the grinding stone identified by the remaining amount identification unit is below the allowable value of the grinding stone remaining amount, it is judged that the grinding stone will be consumed before the grinding of all the wafers in the wafer cassette is completed, and a notification is made.

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