JP5611012B2 - Cutting blade detection mechanism - Google Patents

Description

  The present invention relates to a cutting blade detection mechanism in a cutting apparatus.

  A semiconductor wafer in which a number of devices such as IC and LSI are formed on the surface, and each device is partitioned by a line to be divided (street), the back surface is ground by a grinding machine and processed to a predetermined thickness. A dividing line is cut by a cutting device to be divided into individual devices, and the divided devices are widely used in electric devices such as mobile phones and personal computers.

  The cutting apparatus includes at least a chuck table that holds a workpiece such as a semiconductor wafer, and a cutting means that rotatably supports a cutting blade that cuts the workpiece held on the chuck table. Can be divided into individual devices with accuracy.

  In the cutting device, the cutting feed amount of the cutting blade to the workpiece is managed based on the outer diameter size of the cutting blade with the upper surface of the chuck table (workpiece holding surface) as a reference point. Since the outer diameter of the cutting blade varies from cutting blade to cutting blade, when the blade is replaced with a new cutting blade, the cutting blade and the holding surface of the chuck table are brought into contact with each other to detect the origin position (reference point position) (for example, JP, 61-71967, A). This detection of the origin position is called contact setup.

  The cutting blade wears with processing and changes in outer diameter size. If cutting is performed with the same cutting amount set while the cutting blade is worn, the cutting amount into the workpiece becomes shallow.

  Therefore, the cutting apparatus performs a setup (reference point finding operation) without contacting the chuck table during machining, and includes a non-contact setup sensor (cutting blade detection mechanism) for detecting wear of the cutting blade. (For example, refer to Japanese Patent Application Laid-Open No. 2003-212354).

  The non-contact setup sensor is provided in the vicinity of the chuck table and includes a transmission type photoelectric sensor including a light emitting unit and a light receiving unit. When a new blade is mounted on the spindle, the relative position between the chuck table top surface and the non-contact setup sensor is detected, and the non-contact setup sensor is used to detect the reference point of the cutting blade during machining. To do.

  In this non-contact setup sensor, the cutting blade is lowered between the light emitting portion and the light receiving portion, and wear of the cutting blade is detected based on the height position (Z position) where the light from the light emitting portion is shielded by the cutting blade.

  On the other hand, a transmissive photoelectric sensor composed of a light emitting part and a light receiving part is positioned in the cutting means so as to sandwich the cutting blade of the cutting blade, and the cutting blade is cut by a change in the amount of light received by the light receiving element of the light receiving part. A cutting blade detection mechanism for detecting chipping of the blade is provided. When the cutting blade detection mechanism detects the chipping of the cutting blade, the cutting blade is replaced with a new cutting blade (see, for example, Japanese Patent Application Laid-Open No. 2007-2770).

  In the transmissive photoelectric sensor, the amount of light received by the light receiving unit is converted into an electric signal, and the electric signal is amplified by an amplifier so that the electric signal becomes a constant value (first value). That is, in the transmission type photoelectric sensor, in order to accurately detect the wear of the cutting blade, the electric signal output from the amplifier detected in a state where the cutting blade is not located between the light emitting portion and the light receiving portion is maintained at a constant value. This is very important.

  However, the amount of light emission decreases as the light emitting element connected to the light emitting portion deteriorates with time, and the light receiving sensitivity decreases because the light receiving element connected to the light receiving portion deteriorates over time.

JP 2003-2111354 A JP 2007-2770 A

  Conventionally, whenever the light emission amount of the light emitting unit decreases due to deterioration with time of the light emitting element, or whenever the sensitivity of the light receiving element decreases due to deterioration with time of the light receiving element, the operator increases the amplification amount of the amplifier and outputs from the amplifier. Although the electric signal is controlled to be a constant value, there is a problem that it is troublesome for the operator to adjust each time the light emission amount decreases or the light receiving sensitivity decreases.

  The present invention has been made in view of these points, and an object thereof is a cutting blade capable of automatically adjusting an amplification amount of an amplifier so that an electric signal output from the amplifier becomes a constant value. It is to provide a detection mechanism.

  According to the present invention, a cutting device comprising: a chuck table that holds a workpiece; a cutting means that includes a cutting blade that cuts the workpiece held on the chuck table; and a spindle on which the cutting blade is mounted. A cutting blade detection mechanism used in an apparatus, comprising: a light emitting element; a light emitting part connected to the light emitting element; a light receiving part arranged to receive light from the light emitting part; and the light receiving part A light receiving element that converts the amount of light received by the light receiving unit into an electric signal, and an electric signal obtained by converting the amount of light received by the light receiving unit with the light receiving unit without a cutting blade between the light emitting unit and the light receiving unit. An amplifying unit that amplifies an electric signal in accordance with deterioration over time of the light emitting element and the light receiving element so as to have a value of 1, a receiving unit that receives an electric signal from the amplifying unit, and an electric signal received by the receiving unit The signal becomes the first value Control means comprising: an amplification control unit that controls the amplification amount of the amplification unit; and a warning transmission unit that issues a warning when the amplification amount reaches an upper limit value and prohibits amplification beyond the upper limit value of the amplification unit A cutting blade detection mechanism is provided.

  According to the cutting blade detection mechanism of the present invention, since the amplification amount of the amplifier is automatically adjusted so that the electric signal output from the amplifier becomes a constant value, the operator is freed from the trouble of adjusting the amplification amount of the amplifier. The

It is an external appearance perspective view of a cutting device. It is a perspective view of the semiconductor wafer supported by the annular frame via the dicing tape. It is a disassembled perspective view of a cutting means. It is a perspective view of a cutting means. It is a whole block diagram of the cutting-blade detection mechanism of 1st Embodiment of this invention. It is a whole block diagram of the cutting blade detection mechanism of 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an external view of a cutting device (dicing device) 2 that can divide a wafer into individual chips (devices).

  On the front side of the cutting device 2, there is provided operating means 4 for an operator to input instructions to the device such as machining conditions. In the upper part of the apparatus, there is provided a display means 6 such as a CRT for displaying a guidance screen for an operator and an image taken by an imaging means described later.

  As shown in FIG. 2, on the surface of the wafer W to be diced, the first street S1 and the second street S2 are formed orthogonally, and the first street S1 and the second street S2 A large number of devices D are formed on the wafer W.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer peripheral edge of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the frame F via the dicing tape T, and a plurality of wafers (for example, 25 sheets) are accommodated in the wafer cassette 8 shown in FIG. The wafer cassette 8 is placed on a cassette elevator 9 that can move up and down.

  Behind the wafer cassette 8, a loading / unloading means 10 for unloading the wafer W before cutting from the wafer cassette 8 and loading the wafer after cutting into the wafer cassette 8 is disposed. Between the wafer cassette 8 and the loading / unloading means 10, a temporary placement area 12, which is an area on which a wafer to be carried in / out, is temporarily placed, is provided. Positioning means 14 for positioning at a certain position is provided.

  In the vicinity of the temporary placement area 12, transport means 16 having a turning arm that sucks and transports the frame F integrated with the wafer W is disposed, and the wafer W carried to the temporary placement area 12 is Adsorbed by the conveying means 16 and conveyed onto the chuck table 18 and sucked by the chuck table 18, and held on the chuck table 18 by fixing the frame F by a plurality of fixing means (clamps) 19. .

  The chuck table 18 is configured to be rotatable and reciprocally movable in the X-axis direction. Above the movement path of the chuck table 18 in the X-axis direction, an alignment unit 20 that detects a street to be cut of the wafer W is provided. It is arranged.

  The alignment unit 20 includes an imaging unit 22 that images the surface of the wafer W, and can detect a street to be cut by image processing such as pattern matching based on an image acquired by imaging. The image acquired by the imaging unit 22 is displayed on the display unit 6.

  On the left side of the alignment means 20, a cutting means 24 for cutting the wafer W held on the chuck table 18 is disposed. The cutting means 24 is configured integrally with the alignment means 20, and both move together in the Y-axis direction and the Z-axis direction.

  The cutting means 24 is configured by attaching a cutting blade 28 to the tip of a rotatable spindle 26 and is movable in the Y-axis direction and the Z-axis direction. The cutting blade 28 is located on the extended line of the imaging means 22 in the X-axis direction.

  Referring to FIG. 3, an exploded perspective view of the cutting means 24 is shown. FIG. 4 is a perspective view of the cutting means 24. Reference numeral 25 denotes a spindle housing of the cutting means 24, and a spindle 26 that is rotationally driven by a servo motor (not shown) is rotatably accommodated in the spindle housing 25. The cutting blade 28 is an electroformed blade, and has a cutting edge 28a formed by dispersing diamond abrasive grains in a nickel base material on the outer peripheral portion.

  A blade cover 30 covers the cutting blade 28, and a cutting water nozzle 32 extending along the side surface of the cutting blade 28 is attached thereto. Cutting water is supplied to the cutting water nozzle 32 through the pipe 34. The blade cover 30 has screw holes 36 and 38.

  A detachable cover 40 has a cutting water nozzle 42 that extends along the side surface of the cutting blade 28 when attached to the blade cover 30. The cutting water is supplied to the cutting water nozzle 42 via the pipe 44.

  The detachable cover 40 is fixed to the blade cover 30 by inserting the screw 48 into the round hole 46 of the detachable cover 40 and screwing it into the screw hole 36 of the blade cover 30. As a result, the upper half of the cutting blade 28 is covered with the blade cover 30 and the detachable cover 40 as shown in FIG.

  Reference numeral 50 denotes a blade detection fixing block having a round hole 52, and is attached to the blade cover 30 by screwing a screw 54 into the screw hole 38 of the blade cover 30 through the round hole 52. A cutting blade detection mechanism 60 described later is attached to the fixed block 50, and the state of the cutting blade 28a of the cutting blade 28 is detected by the cutting blade detection mechanism 60.

  Next, the configuration of the cutting blade detection mechanism 60 according to the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 5, the cutting blade detection mechanism 60 includes a fixed block 50 fixed to the blade cover 30 and a moving block 62 that can move up and down with respect to the fixed block 50 by rotating an adjustment screw 55. Yes.

  The light emitting means (light emitting assembly) 64 of the cutting blade detection mechanism 60 includes a light emitting element 66 composed of a light emitting diode (LED) or a laser diode (LD), and a plastic optical fiber 68 connected to the light emitting element 66. Is done.

  The end 68 a of the optical fiber 68 is bent in the direction of the cutting edge 28 a of the cutting blade 28 with a bending radius equal to or larger than the minimum bending radius of the optical fiber 68, and the end 68 a of the optical fiber 68 forms the light emitting unit 70. The light emitted from the light emitting unit 70, which is the tip 68a of the optical fiber 68, is set to be perpendicular to the cutting blade 28a. Reference numeral 69 denotes a transparent protective plate.

  The light receiving means (light receiving assembly) 74 includes a light receiving element 76 such as a photodiode (PD) and a plastic optical fiber 78 connected to the light receiving element 76. The light receiving unit 80 is configured by the end portion 78 a of the plastic optical fiber 78. Reference numeral 79 denotes a transparent protective plate.

  The end portion 78 a of the optical fiber 78 constituting the light receiving unit 80 is bent in the direction of the cutting edge 28 a of the cutting blade 28 with a bending radius equal to or larger than the minimum bending radius of the optical fiber 78, and the optical fiber 78 constituting the light receiving unit 80. The end portion 78a is arranged so as to receive the light emitted from the light emitting portion 70.

  The light emitted from the light emitting unit 70 received by the light receiving unit 80 propagates through the optical fiber 78 and is converted into an electrical signal by the light receiving element 76 according to the amount of received light. This electrical signal is amplified by the amplifier (amplifier) 82 to the first value ( The first value is input to the A / D converter 84, for example, 4.5V to 4.95V).

  Reference numeral 85 denotes a cutting blade detection means, a light emitting element 66, a light emitting unit 70 connected to the light emitting element 66 by an optical fiber 68, a light receiving element 76, and a light receiving unit 80 connected to the light receiving element 76 by an optical fiber 78. And an amplifier 82.

  The electric signal converted into the digital signal by the A / D converter 84 is input to the control means 86 via the receiving section 88, and the electric signal received by the receiving section 88 by the amplification control section 90 of the control means 86 is the first value. The amount of amplification of the amplifier 82 is feedback controlled so as to be (for example, 4.5 V to 4.95 V).

  Here, an upper limit value (for example, 2V) is set for the amplification amount of the amplifier 82, and the warning transmission unit 92 of the control means 86 issues a warning when the amplification amount of the amplifier 82 reaches the upper limit value. Amplification beyond the upper limit of 82 is prohibited.

  The control unit 86 further includes a storage unit that stores a second value lower than the first value, and a second warning oscillation unit that issues a warning when the receiving unit 88 falls below the second value. Also good. By setting the second value to 2 V, for example, it is possible to detect whether the light emitting unit 70 and the light receiving unit 80 are dirty.

  It is preferable that the control of the amplification amount of the amplifier 82 of the cutting blade detection mechanism 60 of the present embodiment is automatically performed when the cutting blade 28 is removed. That is, it is necessary to control the amplification amount of the amplifier 82 when the cutting blade 28 is not interposed between the light emitting unit 70 and the light receiving unit 80.

  In this embodiment, when the breakage of the cutting blade 28 is detected and the cutting blade 28 is replaced with a new cutting blade, the amplification amount of the amplifier 82 is automatically adjusted, so that the operator manually adjusts the amplifier 82. You are freed from the hassle of doing.

  When the amplification amount of the amplifier 82 reaches the upper limit value, the warning oscillation unit 92 of the control means 86 displays a warning on the display means 6 or notifies the operator by a buzzer or the like, so that the operator emits light. The element 66 and / or the light receiving element 76 can be easily replaced with a new part.

  Next, the cutting blade detection mechanism 94 according to the second embodiment of the present invention will be described with reference to FIG. The cutting blade detection mechanism 94 of the present embodiment is a non-contact setup sensor and is disposed in the vicinity of the chuck table 18. In the description of the present embodiment, components that are substantially the same as those in the first embodiment described above are given the same reference numerals, and descriptions thereof are omitted to avoid duplication.

  The cutting blade detection mechanism 94 of this embodiment includes a U-shaped block 96 disposed in the vicinity of the chuck table 18, and is attached so that the light emitting unit 70 and the light receiving unit 80 face the U-shaped block 96. ing.

  When the cutting blade 28 is replaced with a new cutting blade, the height direction between the upper surface of the chuck table 18 and the transmission photoelectric sensor composed of the light emitting unit 70 and the light receiving unit 80 of the non-contact setup sensor 94 is determined. The non-contact setup sensor 94 is used to detect the reference point of the cutting blade 28 during processing.

  In this non-contact setup sensor 94, the cutting blade 28 is lowered between the light emitting unit 70 and the light receiving unit 80, and the cutting blade is based on the height position (Z position) where the light from the light emitting unit 70 is shielded by the cutting blade 28. The wear of the 28 cutting blades 28a is detected.

  In the cutting blade detection mechanism (non-contact setup sensor) 94 of the present embodiment, the light receiving element 76 converts the amount of light received by the light receiving unit 80 when the cutting blade 28 is not positioned between the light emitting unit 70 and the light receiving unit 80, Further, the amplification amount of the amplifier 82 is controlled in accordance with the temporal deterioration of the light emitting element 66 and the light receiving element 76 so that the electric signal amplified by the amplifier 82 becomes a first value (for example, 4.9 to 5.1 V). .

  The amplified electric signal is converted into a digital electric signal by the A / D converter 84 and input to the control means 86 via the receiving unit 88. The amplification control unit 90 of the control unit 86 feedback-controls the amplification amount of the amplifier 82 so that the electric signal received by the reception unit 88 becomes the first value (4.9 to 5.1 V) described above. The warning oscillation unit 92 issues a warning when the amplification amount of the amplifier 82 reaches an upper limit value (for example, 2V) and prohibits amplification beyond the upper limit value of the amplifier 82.

  The feedback control of the amplification amount of the amplifier 82 of the present embodiment may be performed at all times since the cutting blade 28 is not inserted between the light emitting unit 70 and the light receiving unit 80 during the cutting process.

  Alternatively, it may be performed at a predetermined timing. For example, the operator may arbitrarily select and perform the operation automatically at a certain timing when the cutting blade 28 is replaced.

  In the cutting blade detection mechanism (non-contact setup sensor) 94 of the present embodiment, the operator automatically adjusts the amplification amount of the amplifier 82 so that the electrical signal received by the receiving unit 88 becomes the first value. This frees you from the hassle of adjusting the amplification amount of the amplifier 82.

18 Chuck table 24 Cutting means 28 Cutting blade 28a Cutting blade 60 Cutting blade detection mechanism 64 Light emitting means 66 Light emitting element 68 Optical fiber 70 Light emitting part 74 Light receiving means 76 Light receiving element 78 Optical fiber 80 Light receiving part 82 Amplifier 85 Cutting blade detecting means 86 Control Means 90 Amplification control unit 92 Warning oscillation unit 94 Cutting blade detection mechanism (non-contact setup sensor)
96 U-shaped block

Claims (1)

Used in a cutting apparatus comprising a chuck table for holding a workpiece, a cutting blade including a cutting blade for cutting the workpiece held on the chuck table, and a spindle on which the cutting blade is mounted. A cutting blade detection mechanism,
A light emitting element;
A light emitting unit connected to the light emitting element;
A light receiving portion arranged to receive light from the light emitting portion;
A light receiving element that converts the amount of light received by the light receiving unit into an electrical signal;
The light-emitting element and the light-receiving element have an electric signal obtained by converting the amount of light received by the light-receiving unit with the light-receiving element in a state in which no cutting blade is positioned between the light-emitting unit and the light-receiving unit. An amplifying unit for amplifying an electric signal according to deterioration over time;
A receiving unit that receives an electric signal from the amplifying unit; an amplification control unit that controls an amplification amount of the amplifying unit so that the electric signal received by the receiving unit becomes the first value; and Control means having a warning transmitter for issuing a warning when the upper limit is reached and prohibiting amplification of the amplifier above the upper limit;
A cutting blade detection mechanism comprising:

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