JP5506523B2 - Cutting equipment - Google Patents

Description

  The present invention relates to a cutting apparatus provided with blade detection means for detecting a reference position in a cutting direction of a cutting blade of the cutting apparatus and a replacement time of the cutting blade.

  Many electronic components that require precision cutting, such as semiconductor wafers, ceramics, and glass, are divided into individual chips by a cutting device called a dicing saw. This cutting requires precise precision in the order of microns. Yes, not only the chip size but also the cutting depth is important.

  For example, when a semiconductor wafer is divided into individual chips, the semiconductor wafer is fixed to a dicing tape, and the semiconductor wafer is completely cut by cutting a cutting blade of about 10 to 30 μm into the dicing tape. If the amount of cut is insufficient, the wafer is not completely divided into chips, or chipping called chipping occurs on the cut side of the lower surface, which causes problems in chip quality.

  Further, since the cutting blade has a property of being consumed as cutting is continued, it is necessary to detect the amount of consumption and to correct the height position of the blade as needed. Furthermore, when the consumption amount of the cutting blade reaches the use limit amount, it is necessary to replace it with a new cutting blade.

  For this reason, the cutting apparatus needs to adjust the reference position in the cutting direction of the cutting blade in response to a decrease in the diameter of the cutting blade, and includes a blade detection mechanism for detecting the reference position.

  A conventional blade detection mechanism is composed of an optical sensor having a light emitting part and a light receiving part. With this blade detection mechanism, the amount of wear of the cutting blade is detected at any time (setup), the blade height position correction during cutting and the end of use It has been useful for the determination (see, for example, JP-A-11-214334).

  Such a blade detection mechanism is used in combination with an origin position detection mechanism that detects the origin position of the cutting blade by cutting the cutting blade into the frame of the chuck table made of metal and conducting it.

  The origin position of the cutting blade detected by this origin position detection mechanism is to cut a workpiece such as a wafer, so that the cutting blade is lowered to cut only the workpiece and not to the chuck table. It becomes a standard to set up. In the origin position detection mechanism, since the cutting blade cuts into the upper surface of the frame body of the chuck table, the upper surface of the frame body is damaged, and it is not a good idea to frequently detect the origin position with the origin position detection mechanism.

  Therefore, a blade detection mechanism is provided in the vicinity of the chuck table in addition to the origin position detection mechanism, and the blade detection mechanism detects the position of the blade edge in the cutting direction, and the chuck table holding surface position and the detection position of the blade detection mechanism. The origin position of the cutting blade is detected by correcting the difference in height direction (cutting direction).

JP-A-11-214334 Japanese Patent No. 4036161

  However, since the blade detection mechanism using the optical sensor has a structure in which the optical sensor is exposed, there is a drawback in that if it becomes dirty, its sensitivity falls and accurate detection cannot be performed. Furthermore, since the position of the blade tip is detected by blocking the light between the light emitting part and the light receiving part of the optical sensor with the blade, it is necessary to have a convex part containing an optical fiber that sandwiches the blade, and the structure is complicated. It becomes.

  Further, there is a problem in that it is difficult to measure a slit blade in which slits are intermittently formed on the cutting blade of the cutting blade because the light interception changes intermittently with an optical sensor.

  The present invention has been made in view of these points, and an object of the present invention is to provide a cutting device incorporating a blade detection mechanism capable of detecting the height position of the lower end of the cutting blade with a simple structure. That is.

According to the present invention, a chuck table having a holding surface for holding a workpiece, a cutting means having a spindle for rotatably supporting a cutting blade for cutting the workpiece held on the chuck table, and the cutting blade A blade detecting means for detecting the height position of the lower end of the blade, wherein the blade detecting means detects the wind pressure generated by the airflow around the rotating cutting blade, and voltage according to the wind pressure. The blade detection means is embedded outside the area of the holding surface of the chuck table, and the upper end of the blade detection means and the holding surface are formed flush with each other . A cutting device is provided.

  According to the present invention, since the blade detection means includes the pressure sensor that detects the wind pressure generated by the airflow around the cutting blade and generates a voltage according to the wind pressure, the sensor element is included in the small frame that covers the element. Since it is built-in and not exposed to the surface, it has the feature of being difficult to get dirty.

  In addition, since the upper surface of the pressure sensor frame containing the sensor element can be flat, unlike the optical sensor that requires a convex portion to accommodate the optical fiber, the upper surface of the optical sensor can be embedded directly in the chuck table. The holding surface of the chuck table can be formed flush with each other, and the space for the blade detecting means can be saved.

It is a perspective view of a cutting device. It is a surface side perspective view of the semiconductor wafer supported by the annular frame via the dicing tape. It is sectional drawing of the state which has detected the height position of the lower end part of a cutting blade with the blade detection means of 1st Embodiment of this invention embedded in the frame of the chuck table. It is a schematic diagram explaining the relationship between the wind pressure around the rotating cutting blade and the pressure sensor which detects this wind pressure. It is sectional drawing of the state which is cutting the semiconductor wafer using the chuck table shown in FIG. It is sectional drawing of the state which has detected the height position of the cutting blade lower end part by the blade detection means of 2nd Embodiment of this invention provided adjacent to the chuck table. It is a block diagram of a blade detection means. It is a graph which shows the change of the output voltage of a blade detection means according to the height position (position of a cutting direction) of the lower end part of a cutting blade.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a block diagram of a cutting apparatus 2 suitable for incorporating the blade detection means (blade detection mechanism) of the present invention. The cutting device 2 includes a pair of guide rails 6 that are mounted on a stationary base 4 and extend in the X-axis direction.

  Reference numeral 8 denotes an X-axis movement block. The X-axis movement block 8 is moved in the machining feed direction, that is, the X-axis direction by an X-axis feed mechanism 14 including a ball screw 10 and a pulse motor 12. A chuck table 20 is mounted on the X-axis moving block 8 via a motor 27 and a table base 22.

  The chuck table 20 includes a suction holding portion (suction chuck) 24 formed of porous ceramics and the like, and a frame body 23 formed of metal such as SUS surrounding the suction chuck 24. The holding surface of the suction holding unit 24 and the upper surface of the frame body 23 are formed flush with each other. The chuck table 20 is provided with a plurality (four in this embodiment) of clamps 26 for clamping the annular frame F shown in FIG. Reference numeral 25 denotes a waterproof cover.

  As shown in FIG. 2, the first street S1 and the second street S2 are formed orthogonal to each other on the surface of the semiconductor wafer W to be processed by the cutting apparatus 2, and the first street S1 A device D is formed in each of the areas partitioned by the second street S2.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer periphery of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the annular frame F via the dicing tape T, and is clamped on the chuck table 20 by clamping the annular frame F by the clamper 26 shown in FIG.

  The X-axis feed mechanism 14 includes a linear scale 16 disposed on the stationary base 4 along the guide rail 6 and a reading head 18 disposed on the lower surface of the table base 8 that reads the X coordinate value of the linear scale 16. Including. The read head 18 is connected to the controller of the cutting device 2.

  A pair of guide rails 28 extending in the Y-axis direction are further fixed on the stationary base 4. The Y-axis moving block 30 is moved in the Y-axis direction by a Y-axis feed mechanism (index feed mechanism) 36 composed of a ball screw 32 and a pulse motor 34.

  Although not particularly illustrated, the Y-axis feed mechanism 36 is arranged on the linear scale disposed on the stationary base 4 along the guide rail 28 and the lower surface of the Y-axis moving block 30 that reads the Y coordinate value of the linear scale. The reading head is provided, and the reading head is connected to the controller of the cutting device 2.

  The Y-axis moving block 30 is formed with a pair of guide rails 38 (only one is shown) extending in the Z-axis direction. The Z-axis moving block 40 is moved in the Z-axis direction by a Z-axis feed mechanism 44 composed of a ball screw 41 (see FIG. 7) and a pulse motor 42.

  Although not specifically illustrated, the Z-axis feed mechanism 44 is disposed on the linear scale disposed on the Y-axis movement block 30 along the guide rail 38 and the Z-axis movement block 40 that reads the Z coordinate value of the linear scale. The read head is connected to the controller of the cutting device 2.

  Reference numeral 46 denotes a cutting unit (cutting means), and a spindle housing 48 of the cutting unit 46 is inserted into and supported by the Z-axis moving block 40. A spindle 49 (see FIG. 3) is accommodated in the spindle housing 48 and is rotatably supported by an air bearing. The spindle 49 is rotationally driven by a motor (not shown) housed in a spindle housing 48, and a cutting blade 50 is detachably attached to the tip of the spindle 49.

  An alignment unit (alignment means) 52 is mounted on the spindle housing 48. The alignment unit 52 has an imaging unit (imaging means) 54 that images the wafer W held on the chuck table 20. The cutting blade 50 and the imaging unit 54 are arranged in alignment in the X-axis direction.

  Referring to FIG. 3, there is shown a cross-sectional view of an essential part of a cutting apparatus provided with blade detecting means (blade detecting mechanism) according to the first embodiment of the present invention. In the present embodiment, the blade detection means includes a pressure sensor 62 embedded in the frame body 23 of the chuck table 20.

  The suction holding unit 24 of the chuck table 20 is connected to a suction source 60 via a suction path 58 and a switching valve 59. The pressure sensor 62 is connected to a control means (controller) 66 through a wiring 64. A waterproof cover 25 is disposed on the X-axis moving block 8, and a bellows 56 is attached to the waterproof cover 25. 75 is a packing.

  A cutting blade 50 is fixed to a tip end portion of a spindle 49 accommodated in a spindle housing 48 of the cutting unit 46 by being sandwiched between a mount flange 51 and a detachable flange 53. Reference numeral 55 denotes a wheel cover (blade cover). FIG. 3 shows a state in which the height position (cutting direction position) of the lower end portion of the cutting blade 50 rotating at high speed is detected by the pressure sensor 62.

  As shown in FIG. 4, when the cutting blade 50 rotates at a high speed (for example, 30000 rpm), wind pressure is generated by the airflow around the cutting blade 50. This wind pressure is strong in the vicinity of the cutting blade 50 indicated by A, and becomes weak at a position away from the cutting blade 50 indicated by B. Reference numeral 50a denotes a cutting blade at the tip of the cutting blade 50.

The pressure sensor 62 has a sensor element 68 made of piezoelectric ceramics. The sensor element 68 is made of, for example, lead zirconate titanate (Pb (Ti · Zr) O ₃ ) or lead titanate (PbTiO ₃ ).

  The pressure sensor 62 has a plate 70 whose upper surface is flush with the holding surface of the suction holding unit 24 of the chuck table 20, and the air flow is indicated by an arrow C through the opening 71 of the plate 70. The sensor element 68 detects (measures) the wind pressure associated with the airflow, and outputs a voltage corresponding to the detected wind pressure level.

  Therefore, the height position of the lower end portion of the cutting blade 50 can be detected by measuring the voltage generated by the pressure sensor 62. The detection of the reference position of the cutting blade 50 will be described in detail later with reference to FIGS.

  Referring to FIG. 5, there is shown a cross-sectional view of a state where cutting is performed on the wafer W by the cutting apparatus shown in FIG. The semiconductor wafer W is sucked and held by the suction holding portion 24 of the chuck table 20 via the dicing tape T, and the annular frame F is clamped by the clamp 26 to fix the annular frame F.

  In this state, the cutting blade 50 is cut about 10 μm into the dicing tape T while rotating at high speed, and the chuck table 20 is processed and fed in the X-axis direction, so that the wafer W is fully cut along the first street S1.

  As apparent from FIG. 5, since the pressure sensor 62 of the present embodiment is embedded in the frame body 23 of the chuck table 20, the pressure sensor 62 is covered with the dicing tape T during the cutting process. The reference position of the cutting blade 50 cannot be detected by the pressure sensor 62.

  A cutting apparatus provided with a blade detection means (blade detection mechanism) according to a second embodiment of the present invention that eliminates this point will be described with reference to FIGS. In the description of the present embodiment, substantially the same components as those of the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted to avoid duplication.

  In the present embodiment, a blade detection means (blade detection mechanism) 72 is disposed adjacent to the chuck table 20. The blade detection means 72 includes a vertical support member 74 erected from the X-axis moving block, and a horizontal support member 76 that is fixed to the vertical support member 74 and extends so as to protrude from the vertical support member 74 to the side of the chuck table 20. And a pressure sensor 62 mounted on the horizontal support member 76. The pressure sensor 62 has an openable / closable cover 78 for preventing dirt from adhering to the sensor.

  Next, the operation of the blade detection means 72 of this embodiment will be described with reference to FIGS. When a new chuck table 20 is mounted, or when the chuck table 20 is disassembled and reassembled after cleaning, the cutting blade 50 is first cut into the frame body 23 of the chuck table 20 by the origin position detection mechanism. Then, the origin position of the cutting blade 50 is detected, and this origin position is stored in the memory of the controller (control means) 66 of the cutting apparatus 2.

  Next, the reference position detection for detecting the reference position in the cutting direction of the cutting blade 50a of the cutting blade 50 by the blade detection means 72 is performed. This reference position detection will be described with reference to FIG.

  The pressure sensor 62 outputs a voltage corresponding to the wind pressure detected by the sensor element 68, and this voltage is input to the voltage comparison unit 80 via the wiring 64. On the other hand, a reference voltage (for example, 3 V) set by the reference voltage setting unit 82 is input to the voltage comparison unit 80.

  The voltage comparison unit 80 compares the output voltage from the pressure sensor 62 with the reference voltage set by the reference voltage setting unit 82, and when the output voltage from the pressure sensor 62 reaches the reference voltage, the signal indicating that is output. To the part position detector 84.

  More specifically, when detecting the reference position of the cutting blade 50 in the cutting direction, the pulse motor 42 of the Z-axis feed mechanism 44 is driven to bring the cutting blade 50 closer to the pressure sensor 62 from above.

  The pressure sensor 62 detects the wind pressure generated by the air current around the cutting blade 50 that rotates at high speed, and outputs a voltage corresponding to the wind pressure. Therefore, the voltage is generated when the tip of the cutting blade 50 approaches the pressure sensor 62 to a predetermined distance. As the cutting blade 50 is lowered, the output voltage gradually increases as indicated by reference numeral 90 in FIG.

  When the tip of the lower end of the cutting blade 50 reaches the reference position, the output voltage from the pressure sensor 62 is set to 3 V, for example. Therefore, when the output voltage of the pressure sensor 62 reaches 3 V, the voltage comparison unit 80 outputs a signal to the end position detection unit 84 that the output voltage of the pressure sensor 62 has reached the reference voltage.

  The end position detector 84 transmits a signal indicating that the reference position has been detected to the pulse motor 42 and stops driving the pulse motor 42. At this time, the end position detection unit 84 stores the value of the linear scale that detects the position of the cutting blade 50 in the cutting direction (Z-axis direction) as a reference position.

  As shown in FIG. 6, a predetermined height direction (cutting direction) is provided between the height position of the holding surface of the suction holding portion 24 of the chuck table 20 and the reference position of the cutting blade 50 detected by the pressure sensor 62. There is a difference.

  Therefore, since the origin position of the cutting blade 50 detected by the origin position detection mechanism and the reference position of the cutting blade 50 detected by the blade detection means 72 are both stored in the memory, the cutting blade 50 detected by the blade detection means 72 is stored. Is corrected by the difference between the origin position and the reference position, and the origin position where the cutting blade 50 contacts the upper surface of the frame body 23 of the chuck table 20 is detected based on the reference position detected by the blade detection means 72. can do.

  Since the difference between the origin position of the cutting blade 50 and the reference position of the cutting blade 50 detected by the blade detecting means 72 varies due to an assembly error of the cutting device, the difference is obtained for each cutting device and stored in the memory. The

  Therefore, when it becomes necessary to re-detect the origin position of the cutting blade 50 during the normal cutting process, the blade detection means 72 detects the reference position of the cutting blade 50, and this reference position is stored in advance. The original position of the cutting blade 50 is corrected by the correction value.

  Accordingly, it is possible to minimize the necessity of cutting the top surface of the frame body 23 of the chuck table 20 with the cutting blade 50 to detect the origin position, and it is possible to suppress damage to the top surface of the frame body 23.

  When the cutting blade 50 is worn, the rotation center of the blade is gradually lowered. Therefore, by continuously detecting the reference position of the cutting blade 50 using the blade detection means 72, the amount of wear (amount of wear) of the cutting blade 50 is detected. Can be detected.

  The reference position of the cutting blade 50 detected by the end position detection unit 84 is stored in the memory of the controller 66 as the number of pulses of the pulse motor 42 from the origin position, and is further input to the calculation unit 86. The calculation unit 86 compares the number of pulses at the reference position calculated and stored last time with the number of pulses at the reference position calculated this time, and calculates the amount of wear of the cutting blade 50.

  Based on the desired amount of the cutting blade 50 calculated by the calculation unit 86, the position correction unit 88 corrects the origin position of the cutting blade 50 in the Z-axis direction. By correcting the origin position, the tip of the cutting blade 50a of the cutting blade 50 can be brought to a position where it contacts the upper surface of the frame body 23 of the chuck table 20.

  According to the above-described embodiment, the pressure sensor 62 using piezoelectric ceramics that can also detect fine fluctuations in wind pressure is used to detect the reference position of the cutting blade 50, thereby causing an airflow around the cutting blade 50 that rotates at high speed. The reference position of the cutting blade 50 can be detected by detecting the generated wind pressure, and the sensor element 68 formed of piezoelectric ceramics is covered with a cover when the sensor is not used, so that it is difficult to get dirty.

  Further, since the upper surface of the frame containing the pressure sensor 62 can be formed flat, the pressure sensor 62 is directly embedded in the chuck table 20 as in the first embodiment shown in FIG. The holding surface of the table 20 can be formed flush with each other, and a space for installing the blade detecting means can be saved.

2 Cutting device 8 X-axis moving block 20 Chuck table 23 Frame body 24 Suction holding unit 50 Cutting blade 62 Pressure sensor 68 Sensor element 72 Blade detection means (blade detection mechanism)
78 Cover

Claims (1)

A chuck table having a holding surface for holding a workpiece, a cutting means having a spindle for rotatably supporting a cutting blade for cutting the workpiece held on the chuck table, and a height of a lower end portion of the cutting blade A cutting device comprising a blade detecting means for detecting the position,
The blade detection means includes a pressure sensor that detects a wind pressure generated by an airflow around the rotating cutting blade and outputs a voltage according to the wind pressure ;
The blade detecting means is embedded outside the area of the holding surface of the chuck table, and the upper end of the blade detecting means and the holding surface are formed flush with each other .

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