JP4791813B2 - Cutting equipment - Google Patents

Description

  The present invention relates to a cutting apparatus provided with a cutting blade, and more particularly to a cutting apparatus having a function of detecting a state such as chipping or wear of the cutting blade.

  A wafer on which a plurality of devices such as IC and LSI are formed is divided into individual chips by cutting vertically and horizontally using a cutting blade that rotates at high speed, and is used in various electronic devices.

  The cutting blade is used by being mounted on a spindle that can rotate at a high speed, and a cutting edge portion is formed on the outer periphery thereof. Since this cutting blade part is formed by solidifying abrasive grains made of diamond or the like by electroforming, metal bond, resin bond, etc., each piece formed by cutting deteriorates with time due to cutting and causes chipping or wear. There is a problem of reducing the quality of the device.

  In order to solve such a problem, the present applicant images the outer peripheral edge of the cutting blade part constituting the cutting blade, confirms its shape, and immediately replaces the cutting blade when an unacceptable chipping or the like occurs. The device which can do was developed (refer patent document 1). In such an apparatus, the light emitted from the light emitting element is guided to the output end near the cutting blade by an optical transmission means such as an optical fiber, and the light is irradiated to the cutting blade, and the reflected light is irradiated to the light from the optical fiber or the like. The reflected light is imaged by guiding it to the light receiving element by the transmission means.

Japanese Patent No. 2627913

  However, when cutting with the cutting blade, it is necessary to supply cutting water to the contact portion between the cutting blade and the workpiece. Therefore, in the configuration in which reflected light is imaged by irradiating the cutting blade with light, the reflected light may be scattered by the splash of cutting water scattered by the high speed rotation of the cutting blade, and the cutting blade may not be recognized from the acquired image. In some cases, chipping or wear of the cutting blade cannot be detected.

  Also, the light emitted from the light emitting element is guided to the vicinity of the cutting blade by the optical fiber, and the reflected light is also guided to the light receiving element by the optical fiber. There is also a problem. Further, since the cutting means including the cutting blade moves at the time of cutting, the optical fiber is also moved. However, the inflexible optical fiber also has a problem of hindering the movement.

  Therefore, the problem to be solved by the present invention is to take an image so that the state of the cutting blade can be reliably grasped without being constrained by the wiring of the optical fiber.

The present invention relates to a chuck table for holding a workpiece, a cutting means having a cutting blade for cutting the workpiece held on the chuck table, and a cutting blade detection means for detecting the state of the cutting blade portion of the cutting blade. The cutting means includes a blade cover having a cutting water nozzle that supplies cutting water to the cutting blade, and the cutting blade detection means emits light to the cutting blade portion of the cutting blade. A light emitting means including a light source , a reflecting mirror that reflects the light so that the emitted light is irradiated to the cutting blade portion of the cutting blade, and an imaging device that faces the light emitting device and images the cutting blade portion of the cutting blade , low and imaging means including a microscope and a positioned in the path of the light emitted from the light emitting means reflector for transmitting the microscope is reflected an image comprising a cutting blade Also has a light emitting means and the imaging means is mounted on the blade cover, the imaging means, chipping determination unit that determines whether the magnitude of chipping of the cutting edge of the cutting blade exceeds the allowable value is connected The light source is connected to a blinking control unit that causes the light source to blink, and the blinking control unit obtains the diameter of the cutting blade of the cutting blade by D [mm] and the rotation speed of the cutting blade by M [rpm] by the imaging unit. The width of the outer peripheral edge portion of the cutting blade portion of the cutting blade in one image is W [mm], and the number of images K required to image the entire circumference of the outer peripheral edge portion of the cutting blade portion of the cutting blade,
K ≧ πD / W
Sought by,
N and n are any positive integers from 0, and the timing T at which the light emitting means emits light is
T [seconds] = {60 [seconds] / M} N + {60 [seconds] / (MK)} n
Sought by,
n can vary from 0 to K.

  In the present invention, since the light emitting means and the imaging means are configured to face each other, in the image acquired by causing the light emitting means to emit light at the time of imaging, the contrast between the portion blocked by the cutting blade and the portion not blocked is clear, Even if there is a splash of cutting water that scatters, an image that can clearly recognize the outer peripheral shape of the cutting blade portion of the cutting blade can be acquired. Further, since the light emitting means and the image pickup means are mounted on the blade cover, it is not necessary to use an optical fiber, and wiring is not necessary.

The diameter of the cutting blade portion of the cutting blade is D [mm], the rotation speed of the cutting blade is M [rpm], and the width of the outer peripheral edge of the cutting blade portion of the cutting blade in one image acquired by the imaging unit is W [ mm], and the blinking control unit calculates the number K of images necessary for imaging the entire circumference of the outer peripheral edge of the cutting blade,
K ≧ πD / W
N and n are increased from 0 to an arbitrary positive integer, and a time point T at which the light emitting unit emits light is determined.
T [seconds] = {60 [seconds] / M} N + {60 [seconds] / (MK)} n
To determine, it is possible to obtain an image that can clearly recognize the entire region of the outer peripheral edge portion of the cutting edge of the cutting blade. In addition, by setting N and n as variables, the timing of imaging can be adjusted as appropriate by setting them flexibly.

Since the chipping judging section for judging whether the magnitude of chipping of the cutting edge of the cutting blade exceeds the allowable value is connected to the imaging means, immediately to that effect to the operator when the crack has exceeded the allowable value The operator can immediately change the cutting blade.

  A cutting device 1 shown in FIG. 1 is a device that cuts a workpiece and divides the workpiece into individual chips, and an operation means 2 for an operator to input various information such as cutting conditions is provided on the front side thereof. It has been. In addition, a display unit 3 capable of displaying various types of information including images is provided in the upper part of the apparatus.

  An example of the workpiece to be cut is the wafer W shown in FIG. 1 having a plurality of devices formed on the surface. In cutting the wafer W, the wafer W is adhered to the tape T, the ring-shaped frame F is also adhered to the tape T, and the wafer W is integrated with the frame F via the tape T. Become. Thus, a plurality of wafers W supported by the frame F via the tape T are accommodated in the wafer cassette 4.

  On the −Y direction side of the wafer cassette 4, loading / unloading means 5 having a function of unloading the wafer W before cutting from the wafer cassette 4 and storing the cut wafer in the wafer cassette 4 is disposed. Between the wafer cassette 4 and the loading / unloading means 5, a temporary placement area 6 on which the wafer W supported by the frame F is temporarily placed is provided, and the wafer W unloaded from the wafer cassette 6 is In the temporary placement area 6.

  The wafer W unloaded from the wafer cassette 4 and placed in the temporary placement area 6 is held by the transfer means 7 in a state of being integrated with the frame F, and is transferred to the chuck table 8 by its turning.

  The chuck table 8 is configured to be movable in the X-axis direction and to be rotatable, and holds the wafer W via the tape T. Above the movement path of the chuck table 8 in the X-axis direction, an alignment unit 9 that images the wafer by the imaging unit 90 and detects a region to be cut is disposed. The wafer W held on the chuck table 8 is moved immediately below the imaging unit 90 by the movement of the chuck table 8 in the + X direction, the surface of the wafer W is imaged by the imaging unit 90, and the region to be cut is detected by the alignment means 9. The Thereafter, the chuck table 8 further moves in the + X direction, and the wafer W receives the action of the cutting means 10.

  As shown in FIG. 2, the cutting means 10 includes a housing 100, a spindle 101 rotatably supported by the housing 100, a cutting blade 102 attached to the tip of the spindle 101, and the attached cutting blade 102. It consists of a nut 103 to be fixed and a blade cover 104. A cutting blade portion 102 a is fixed to the outer peripheral edge portion of the cutting blade 102. The cutting edge portion 102a is configured by hardening abrasive grains made of diamond or the like by electroforming, metal bond, resin bond, or the like. FIG. 3 shows a state in which the cutting blade 102 is mounted on the spindle 101 and is fixed by the nut 103.

  The cutting blade 102 is covered with a blade cover 104. The blade cover 104 includes a fixed unit 105 that is fixed to the spindle housing 100 and a movable unit 106 that can approach and leave the fixed unit 105.

  A pair of cutting water nozzles 107 for supplying cutting water to the cutting blade 102 are provided at the lower end of the movable unit 106. Two cutting water nozzles 107 are disposed so as to sandwich the cutting blade 102 from the front side (+ Y direction side) and the rear side (−Y direction side), and each cutting water nozzle 107 includes two cutting water nozzles 107 provided at the top. The cutting water flowing in from the cutting water inflow portion 108 is supplied, and the cutting water is discharged from the cutting water nozzle 107 toward the cutting blade 102. Further, on the front side of the movable unit 106, a light emitting means 109 for irradiating light to the cutting edge portion 102a of the cutting blade 102 is provided.

  As shown in FIG. 2, the piston 110 protrudes from the end of the fixed unit 105 on the movable unit 106 side, and the movable unit 106 is fixed to the tip of the piston 110. Air inlets 111a and 111b are provided at the end of the fixed unit 105 on the −X direction side. By supplying air to the air inlet 111a, the piston 110 slides in the + X direction. 106 moves in the + X direction to be in a released state as shown in FIG. On the other hand, when air is supplied to the air inlet 111b, as shown in FIG. 3, the movable unit 106 is positioned most in the −X direction, and the movable unit 106 and the fixed unit 105 are integrated in close contact with each other. The cutting water nozzle 107 is positioned before and after the cutting blade 102.

  A pair of cleaning water nozzles 112 for ejecting cleaning water is disposed below the fixed unit 105. Each of the cleaning water nozzles 112 is located on an extension line in the −X direction of the two cutting water nozzles 107. The cleaning water nozzle 112 is supplied with the cleaning water flowing in from the cleaning water inflow portion 113 provided at the upper part of the fixed unit 105 and ejected.

  An imaging unit 114 is accommodated in the upper part of the fixed unit 105. The imaging means 114 is supported by a bracket 115, and a base 117 is sandwiched between the bracket 115 and the position adjustment unit 116. The position adjustment unit 116 includes a vertically long pore 117 a formed in the base 117. The position of the imaging unit 114 can be adjusted by sliding the position adjusting unit 116 in the vertical direction. The light emitting means 109 and the imaging means 114 constitute a cutting blade detection means 132 that detects the state of the cutting edge portion 102a of the cutting blade 102.

  As shown in FIG. 4, the light emitting means 109 is connected to the blinking control unit 118 and blinks at a timing determined by the blinking control unit 118. The blinking control unit 118 is connected to a rotation number detecting unit 119 that can determine the number of rotations of the spindle 101, and the blinking control unit 118 controls the timing of blinking in the light emitting means 109 according to the number of rotations of the spindle 101. can do.

  The light emitting means 109 includes a light source 120 such as an LED, and a condensing lens 121 and a reflecting mirror 122 are disposed below the light source 120. The light collected by the condenser lens 121 and reflected by the reflecting mirror 122 travels in the horizontal direction (−Y direction) and is directed to the cutting blade portion 102 a of the cutting blade 102 and the imaging means 114.

  In the imaging means 114, a reflecting mirror 123 is disposed on the path of light traveling from the light emitting means 109, and a microscope provided with convex lenses 124 and 125 on the path of light reflected by the reflecting mirror 123 and rising. 126 is arranged. An imaging camera 127 including an imaging element such as a CCD camera is disposed above the microscope 126, and an image magnified by the microscope 126 is converted into an electrical signal by the imaging element.

  The imaging camera 127 is connected to the image processing unit 128, and the image processing unit 128 performs processing on the image information transferred from the imaging camera 127 to the image processing unit 128. The display unit 3 shown in FIG. 1 is connected to the image processing unit 128, and the image processed by the image processing unit 128 can be displayed on the display unit 3. In addition, the image processing unit 128 determines whether the amount of wear of the cutting blade portion 102a of the cutting blade 102 exceeds a predetermined allowable value based on the acquired image, and performs cutting based on the acquired image. The blade 102 is connected to a chipping determination unit 130 that determines whether or not the size of the chipping portion 102a of the blade 102 exceeds a predetermined allowable value.

  Between the light emitting means 109 and the imaging means 114, high-pressure air jetting means 131 for blowing high-pressure air from above onto the cutting blade 102 is disposed, and cutting waste and cutting water adhering to the cutting blade 102 are discharged at high pressure. It can be removed by blowing out air.

  Returning to FIG. 1, after the region to be cut of the wafer W is detected by the alignment means 9, the wafer W moves in the X-axis direction together with the chuck table 8, and the cutting is performed with the high-speed rotation of the cutting blade 102. When the means 10 is lowered, the cutting edge portion 102a of the cutting blade 102 is cut into the region detected by the alignment means 9, and cutting is performed. During cutting, cutting water is supplied from the cutting water nozzle 107 to the wafer W. Further, when the wafer W is moved in the X-axis direction while the cutting means 10 is indexed in the Y-axis direction, and the same cutting is performed after the chuck table 8 is further rotated 90 degrees, the wafer W is cut vertically and horizontally. Divided into individual devices.

  As shown in FIG. 4, the light emitted from the light source 120 is collected by the condenser lens 121, reflected by the reflecting mirror 122, and irradiated toward the cutting edge portion 102 a of the cutting blade 102. Further, since the cutting blade 102a of the cutting blade 102 is on the path of the light reflected by the reflecting mirror 122 constituting the light emitting means 109, the image reflected by the reflecting mirror 123 constituting the imaging means 114 is not included in the cutting blade 102a. The cutting blade part 102a of 102 is included, the image is magnified by the microscope 126 and picked up by the imaging camera 127, and the cutting blade part 102a is reflected in the acquired image. The timing at which the light source 120 emits light can be controlled by the blinking control unit 118, and the light emitting unit 109 functions as a flash during imaging by the imaging unit 114. While the wafer is being cut, the light source 120 periodically emits light, and at the timing when the light source 120 emits light, the imaging unit 114 images an area including the outer peripheral edge portion 102b of the cutting edge portion 102a. In the image acquired by causing the light source 120 to emit light at the time of imaging, the contrast between the portion blocked by the cutting blade 102 and the portion not blocked is clear, so even if the splashes of scattered cutting water are captured together, An image capable of clearly recognizing the outer peripheral edge 102 b of the cutting blade 102 is acquired by the imaging camera 127.

  The image acquired by the imaging camera 127 is displayed on the display means 3 after adding binarization processing or the like in the image processing unit 128 as necessary, and the operator views the image by The chipped state of the cutting edge portion 102a can be grasped.

  The blinking control unit 118 calculates the light emission timing of the light source 120 based on the information regarding the rotation number of the spindle 101 transferred from the rotation number detection unit 119. Specifically, for example, the following processing is performed.

As shown in FIG. 4, the diameter of the cutting edge portion 102a of the cutting blade 102 inputted from the operating means 2 (see FIG. 1) by the operator and stored in advance in a memory or the like is set to D [mm], and the rotational speed detecting portion 119 The detected rotation speed of the cutting blade 102 is set to M [rpm]. Further, the width of the outer peripheral edge portion 102b of the cutting blade 102 reflected in an image acquired by one imaging by the imaging means 114 is set to W [mm], and the blinking control unit 118 converts these values into the following equation (1). By substituting, the number K of images necessary for imaging the entire region of the outer peripheral edge portion 102b is obtained.
K ≧ πD / W (1)

Further, the blinking control unit 118 obtains a timing T for causing the light source 120 to emit light according to the following equation (2).
T [seconds] = {60 [seconds] / M} N + {60 [seconds] / (MK)} n (2)

  When the origin in the rotation of the cutting blade 102 is set, {60 [seconds] / M} N in the first term in the above equation (2) is the timing at which the cutting blade 102 is positioned at the origin. Here, N is a variable that increases from 0 to an arbitrary positive integer, and is increased by, for example, 1 each time the cutting blade 102 rotates once.

  On the other hand, {60 [seconds] / (MK)} n in the second term in the above equation (2) is the timing at which the cutting blade 102 is located at the displacement position from the origin. n is increased by 1 from 0 to K (positive integer) obtained by the equation (1), for example.

  For example, when n is increased from 0 to K while N = 0, K times of imaging are performed during one rotation of the cutting blade 102 at N = 0, whereby the outer peripheral edge portion of the cutting blade 102 is obtained. The entire region 102b can be imaged. In addition, when N = 1, N = 2, N = 3,..., N = K, the imaging interval increases. Then, by increasing n to n = 1, n = 2,..., N = K, every time the cutting blade 102 rotates N times, adjacent regions are imaged one after another, and K times of imaging are performed. The entire region of the outer peripheral edge 102b of the cutting blade 102 can always be imaged. Note that since N and n are variables, the timing of imaging can be adjusted as appropriate by setting them flexibly. For example, if the value of N is only an even number, the entire region of the outer peripheral edge 102 is imaged every other round. Further, when n is fixed to a specific value, it is possible to continue imaging only a specific region of the outer peripheral edge portion 102b.

  When the time point at which the light emitting unit 107a emits light is obtained by the above formulas (1) and (2), and the image is taken by the imaging unit 114 simultaneously with the time of light emission of the light source 120 under the control of the blinking control unit 118, for example, Since an image capable of clearly recognizing the entire region of the outer peripheral edge portion 102b of the 102 can be acquired, it is possible to determine whether the cutting blade 102 is chipped or worn out.

  The image binarized by the image processing unit 128 is transferred to the chipping determination unit 130 and the wear determination unit 129 having a CPU and a memory. The chipping determination unit 129 determines the size and degree of chipping generated in the cutting blade part 102a of the cutting blade 102, and determines whether the chipping exceeds an allowable value. The wear determination unit 129 determines the magnitude and degree of wear occurring on the cutting edge portion 102a of the cutting blade 102, and determines whether the wear exceeds an allowable value. Specifically, the following processing is performed.

  In the missing determination unit 130, the area occupied by the cutting blade portion 102a of the cutting blade 102 in the binarized image is calculated by the number of pixels and stored in the memory. This process may be performed for all captured images, or only a part of the images may be extracted.

  When detecting chipping of the cutting blade 102, the values of all the obtained areas are compared, the maximum value and the minimum value are obtained, and the difference between the maximum value and the minimum value is obtained. The value of this difference indicates the size of the chip generated in the outer peripheral edge portion 102b of the cutting blade 102. That is, when there is no chipping, the difference between the maximum value and the minimum value is zero.

  Next, it is determined whether the obtained difference is equal to or less than a predetermined allowable value. The predetermined allowable value can be input from the operation means 2 shown in FIG. 1 and stored in the memory. If the difference between the maximum value and the minimum value is less than or equal to the allowable value, the chipping determination unit 130 continues cutting as it is because there is no chipping, or even if there is no hindrance to cutting. On the other hand, when the difference between the maximum value and the minimum value exceeds the allowable value, there is a possibility that the quality of the device may be deteriorated if the cutting is continued as it is. Therefore, the lack determination unit 130 notifies the operator of that fact. As a notification method, there is a sound, a display on the display means 3 or the like. The operator who received the notification can avoid the formation of a low-quality device in advance by interrupting the cutting and replacing the cutting blade with a new one.

  When the wear determining unit 129 determines whether the amount of wear of the cutting edge portion 102a of the cutting blade 102 exceeds a predetermined allowable value, the outer peripheral edge portion of the cutting edge portion of an unused cutting blade having no wear is determined. An image is taken in advance and binarized, and the area of the area occupied by the cutting blade in the binarized image is stored in a memory. Then, the obtained area and the area occupied by the cutting blade 102 in the binarized image obtained by imaging and imaging the cutting edge portion 102a of the cutting blade 102 periodically or constantly during cutting, The difference from the area occupied by the unused cutting blade in the image is determined one by one, and if the difference is less than the allowable value previously input and stored in the memory, it is determined that the wear is within the allowable range. On the other hand, if the difference is equal to or greater than the allowable value stored in the memory, it is determined that the wear has exceeded the allowable range, and the operator is notified. The operator who received the notification can avoid the formation of a low-quality device in advance by interrupting the cutting and replacing the cutting blade with a new one.

It is a perspective view which shows an example of the cutting device which concerns on this invention. It is a disassembled perspective view which shows an example of the cutting means which comprises the cutting device. It is a perspective view which shows a cutting means. It is sectional drawing which shows schematically an example of a structure of a cutting blade detection means.

1: Cutting device 2: Operating means 3: Display means 4: Wafer cassette 5: Loading / unloading means 6: Temporary placement area 7: Transfer means 8: Chuck table 9: Alignment means 90: Imaging unit 10: Cutting means 100: Housing 101 : Spindle 102: Cutting blade 102a: Cutting edge portion 102b: Outer peripheral edge portion 103: Nut 104: Blade cover 105: Fixed unit 106: Movable unit 107: Cutting water nozzle 108: Cutting water inflow portion 109: Light emitting means 110: Piston 111a 111b: Air inlet 112: Wash water nozzle 113: Wash water inflow part 114: Imaging means 115: Bracket 116: Position adjustment part 117: Base 117a: Fine hole 118: Flashing control part 119: Rotation speed detection part 120: Light source 121: Condensing lens 122, 123: Reflecting mirror 124, 25: convex lens 126 Microscope 127: imaging camera 128: image processing unit 129: abrasion determination unit 130: chipped determination unit 131: high-pressure air injection means 132: cutting blade detection means

Claims (1)

At least a chuck table for holding a workpiece, a cutting means having a cutting blade for cutting the workpiece held on the chuck table, and a cutting blade detecting means for detecting the state of the cutting blade portion of the cutting blade A cutting device provided,
The cutting means includes a blade cover having a cutting water nozzle for supplying cutting water to the cutting blade,
The cutting blade detection means includes
A light emitting means including a light source for irradiating the cutting blade portion of the cutting blade, and a reflecting mirror for reflecting the light so that the emitted light is irradiated to the cutting blade portion of the cutting blade ;
An imaging device that faces the light emitting means and images the cutting edge portion of the cutting blade , a microscope, and an image including the cutting blade that is positioned on the path of light emitted from the light emitting means and reflects the light to the microscope And at least imaging means including a reflecting mirror for transmitting ,
The light emitting means and the imaging means are attached to the blade cover,
The imaging means is connected to a chipping determination unit that determines whether the chipping of the cutting blade part of the cutting blade exceeds the allowable value,
The light source is connected to a blinking control unit that causes the light source to blink. The blinking control unit is configured such that the diameter of the cutting blade portion of the cutting blade is D [mm], the rotational speed of the cutting blade is M [rpm], Necessary for imaging the entire circumference of the outer peripheral edge of the cutting blade of the cutting blade, where W is the width of the outer peripheral edge of the cutting blade of the cutting blade in one image acquired by the imaging means. K number of images
K ≧ πD / W
Sought by,
N and n are any positive integers from 0, and the timing T at which the light emitting means emits light is
T [seconds] = {60 [seconds] / M} N + {60 [seconds] / (MK)} n
Sought by,
n can vary from 0 to K. Cutting device.

Images