JP5220439B2 - Cutting method of plate - Google Patents

Description

  The present invention relates to a cutting apparatus and a cutting method for cutting a plate-like object such as a semiconductor wafer.

  Semiconductor wafers in which a plurality of electronic circuits such as IC and LSI are formed on a silicon substrate, and various plate materials such as various ceramic substrates, resin substrates, and glass substrates used for electronic components are individually processed by a dicing device (cutting device). Divided into chips, it is widely used in various electronic devices.

  In the cutting process of a plate-like object by a dicing device, the processing position is set by matching a camera reference line generally called a hairline with a planned cutting line. At that time, an operation (hairline alignment) of aligning the reference line of the camera with the center line of the cutting blade is performed in advance.

  Specifically, this hairline alignment operation is performed by processing a groove on the surface of the workpiece once with a cutting blade, imaging the processed groove, performing image processing, and detecting the center of the processed groove. By calculating the amount of deviation between the position and the reference line position of the camera, and adding or subtracting this deviation amount to the coordinate position, the origin position that matches the center position of the machining groove and the reference line position of the camera is stored in the device. Is going on.

When cutting a plate-like object that is actually cut without the reference line of the camera being aligned with the center line of the cutting blade, the wrong position may be cut. It is necessary to prepare.
Japanese Patent Publication No. 2892459

  On the other hand, the thickness of the cutting blade varies from cutting blade to cutting blade, and the cutting blade is attached to the fixed flange of the blade mount mounted on the spindle, but the mounting position differs by about 10 μm every time, so the cutting blade is replaced. It is necessary to perform hairline matching each time.

  That is, in the conventional dicing apparatus, a workpiece for hairline alignment is required every time the blade is replaced, and further, it is necessary to perform a hairline alignment operation by pre-cutting the workpiece.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the cutting device and cutting method which can reduce the frequency | count of cutting accompanying a hairline alignment operation | work.

According to the present invention, a cutting table having a chuck table that holds a plate-like object, and a blade cover that is rotatably mounted with a cutting blade that cuts the plate-like object held on the chuck table and that partially covers the cutting blade. An alignment means for detecting a cutting position of a plate-like object having an optical system in which a reference line for alignment of the cutting blade is formed, and disposed on the blade cover so as to face the cutting blade. Blade detecting means for detecting the distance to the blade, control means for storing the position of the alignment reference line and the distance to the cutting blade detected by the blade detecting means, and controlling the cutting feed of the cutting blade; a method for cutting a plate-like material by using a cutting device and a groove forming step of forming a kerf in the platelet in the first cutting blade, the shape in the groove forming step The blade error detecting step of detecting the distance D between the formed machining groove and the reference line for alignment of the cutting blade and storing it in the control means, and after performing the blade error detecting step, the blade detecting means A first blade distance detecting step of detecting a distance y to one cutting blade and storing the detected value in the control means; and after performing the first blade distance detecting step, removing the first cutting blade A blade replacing step for attaching a second cutting blade, a second blade distance detecting step for detecting a distance y ′ to the second cutting blade by the blade detecting means after the blade replacing step, and the first blade distance A difference (y−y ′) between the first distance y detected in the detection step and the second distance y ′ detected in the second blade distance detection step is calculated, and the difference is calculated as the brace. A correction value calculation step for calculating a value {D + (y−y ′)} added to the distance D detected in the error detection step, and a value {D + (y−y ′)} calculated in the correction value calculation step are cut. And a cutting step of cutting the plate-like object by adding to the feed pitch.

  According to the present invention, after the hairline alignment work is performed once, the blade position can be specified by the blade detection means even if the cutting blade is replaced, so that it is not necessary to perform cutting again for the hairline alignment work, thereby shortening the work time. It becomes possible to do.

  In addition, once the hairline matching operation is performed, a workpiece for hairline alignment becomes unnecessary, which is economical.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an appearance of a cutting apparatus 2 according to an embodiment of the present invention, which can divide a semiconductor 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 plurality of devices D are partitioned and 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 It is attracted by the transport means 16 and transported onto the chuck table 18 and is sucked by the chuck table 18, and is held on the chuck table 18 by fixing the frame F by a plurality of fixing means 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 (optical system) 22 such as a CCD camera that images the surface of the wafer W, and detects a street to be cut by processing such as pattern matching based on an image acquired by imaging. Can do. 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 approximately located on the extension line in the X-axis direction of the alignment reference line (hairline) of the imaging means 22.

  Referring to FIG. 3, an exploded perspective view showing the relationship between the spindle and the blade mount attached to the spindle is shown. A spindle 26 that is rotationally driven by a servo motor (not shown) is rotatably accommodated in a spindle housing 32 of the spindle unit 30. The spindle 26 has a tapered portion 26a and a small distal end portion 26b, and a male screw 34 is formed on the small distal end portion 26b.

  A blade mount 36 includes a boss part (convex part) 38 and a fixed flange 40 formed integrally with the boss part 38, and a male screw 42 is formed on the boss part 38. Further, the blade mount 36 has a mounting hole 43.

  In the blade mount 36, the mounting hole 43 is inserted into the tip small diameter portion 26b and the tapered portion 26a of the spindle 26, and the nut 44 is screwed into the male screw 34 and tightened, so that the tip portion of the spindle 26 as shown in FIG. Attached to.

  FIG. 4 is an exploded perspective view showing a mounting relationship between the spindle 26 to which the blade mount 36 is fixed and the cutting blade 28. The cutting blade 28 is called a hub blade, and is configured by electrodepositing a cutting blade 50 in which diamond abrasive grains are dispersed in a nickel base material on the outer periphery of a circular base 46 having a circular hub 48.

  By inserting the mounting hole 52 of the cutting blade 28 into the boss portion 38 of the blade mount 36 and screwing the fixing nut 54 into the male screw 42 of the boss portion 38 and tightening, the cutting blade 28 is moved to the spindle 26 as shown in FIG. Attached to.

  Referring to FIG. 6, an enlarged perspective view of the cutting means 24 with the cutting blade 28 attached thereto is shown. A blade cover 60 covers the cutting blade 28, and a cutting water nozzle (not shown) that extends along the side surface of the cutting blade 28 is attached to the blade cover 60. Cutting water is supplied to a cutting water nozzle (not shown) via the pipe 72.

  Reference numeral 62 denotes a detachable cover, which is attached to the blade cover 60 with screws 64. The detachable cover 62 has a cutting water nozzle 70 that extends along the side surface of the cutting blade 28 when attached to the blade cover 60. The cutting water is supplied to the cutting water nozzle 70 via the pipe 74.

  A blade detection block 66 is attached to the blade cover 60 with screws 68. As shown in FIG. 7, blade detection means 80 for detecting the distance to the cutting blade 28 is attached to the blade detection block 66 so as to be positioned on one side in the rotation axis direction of the cutting blade 28.

  As the blade detection means 80, for example, a capacitance sensor, an eddy current meter, a laser interferometer, or the like can be employed. Since the blade detection block 66 is attached to a blade cover 60 fixed to the spindle housing 32, and the imaging means 22 such as a CCD camera is fixed to the spindle housing 32, the positions of the imaging means 22 and the blade detection means 80 are fixed. The relationship is always constant.

  Next, with reference to FIG. 8, the cutting method of this embodiment containing a hairline alignment process is demonstrated. First, the first cutting blade 28A is mounted on the blade mount 36 of the spindle 26, and the processing groove 86 is formed in the work piece 81 for hairline alignment using the first cutting blade 28A. The processing groove 86 is imaged by the imaging means 22 and image processing is performed to detect the center of the processing groove 86. Reference numeral 82 denotes a field of view of the imaging means 22.

  Next, the distance D between the center of the machining groove 86 and the alignment reference line 84 of the imaging means 22 is detected, and this distance D is stored in the memory of the control means (not shown) of the cutting device 2. Next, the cutting blade detection means 80 detects the distance y to the first cutting blade 28A, and this distance y is stored in the memory of the control means.

  As a result, the adjustment of the origin position of the first cutting blade 28A is completed, and when the alignment unit 20 performs the alignment, the distance D is always corrected on the image captured by the image capturing unit 22 to perform the cutting. The street to be tried and the cutting blade 28A are aligned.

If the cutting edge 50 of the to continue cutting of the wafer W cutting blade 28A is worn, or if it detects a lack of cutting edge 50 of the cutting blade 28A, replace the cutting blade 28A to a new cutting blade 28 B .

  When replacing the cutting blade, the removable cover 62 of FIG. 6 is removed, the fixing nut 54 is further removed, the cutting blade 28A is removed, a new cutting blade 28B is mounted on the blade mount 36, and tightened with the fixing nut 54.

  Thus, after the new cutting blade 28B is mounted, the blade detection means 80 detects the distance y ′ to the new cutting blade 28B. Next, the difference (y−y ′) between the distance y stored in the control means and the newly detected distance y ′ is calculated, and this difference (y−y ′) is added to the previously detected distance D. A value {D + (y−y ′)} is calculated and used as a correction value.

  When the wafer W is cut by the cutting blade 28B, the correction value {D + (y−) is used when the alignment is performed by the alignment means 20 and the street S to be cut is aligned with the cutting blade 28B. Cutting is performed by adding y ′)} to the cutting feed pitch (street pitch).

  In addition, the chip | tip of the cutting blade 50 is detectable by arrange | positioning the blade detection means 80 facing the cutting blade 50 of the cutting blade 28. FIG.

  As described above, according to the cutting method of the present embodiment, after the hairline alignment work is performed once, the blade position can be specified by the blade detection means 80 even if the cutting blade 28 is replaced. It is possible to reduce the work time. In addition, once the hairline matching operation is performed, a workpiece for hairline matching becomes unnecessary.

It is an appearance perspective view of a cutting device concerning an embodiment of the present invention. It is a perspective view which shows the wafer integrated with the flame | frame. It is a disassembled perspective view which shows the relationship between a spindle unit and the blade mount which should be fixed to a spindle. It is a disassembled perspective view which shows the relationship between a spindle unit and the cutting blade which should be mounted | worn with a spindle. It is a perspective view in the state where a cutting blade was attached to a spindle. It is an expansion perspective view of a cutting means. It is a figure which shows the positional relationship of a cutting blade and a blade detection means. It is explanatory drawing for demonstrating the cutting method of this invention.

Explanation of symbols

2 Cutting device 18 Chuck table 24 Cutting means 26 Spindle 28, 28A, 28B Cutting blade 30 Spindle unit 36 Blade mount 40 Fixing bracket 54 Fixing nut 66 Blade detection block 80 Blade detection block 82 Hairline alignment work piece 84 Alignment reference Line (hairline)
86 Machining groove

Claims (1)

A chuck table for holding a plate-like object, a cutting means having a blade cover that is rotatably attached to a cutting blade for cutting the plate-like object held on the chuck table and partially covers the cutting blade, and the cutting blade And an alignment means for detecting the cutting position of the plate-like object, the blade cover being disposed opposite to the cutting blade, and the distance to the cutting blade being A cutting apparatus comprising: a blade detecting unit for detecting; a position of the alignment reference line; a distance to the cutting blade detected by the blade detecting unit; and a control unit for controlling a cutting feed of the cutting blade. A method of cutting a plate-like object using
A groove forming step of forming a processing groove in the plate-like object with the first cutting blade;
A blade error detection step of detecting a distance D between the processing groove formed in the groove formation step and the reference line for alignment of the cutting blade, and storing the distance D in the control means;
A first blade distance detecting step of detecting a distance y to the first cutting blade by the blade detecting means after storing the blade error detecting step and storing the detected value in the control means;
After performing the first blade distance detecting step, a blade replacing step of removing the first cutting blade and attaching a second cutting blade;
A second blade distance detection step of detecting a distance y ′ to the second cutting blade by the blade detection means after the blade replacement step;
A difference (y−y ′) between the first distance y detected in the first blade distance detection step and the second distance y ′ detected in the second blade distance detection step is calculated, and the difference is calculated as the blade A correction value calculating step of calculating a value {D + (y−y ′)} added to the distance D detected in the error detecting step;
A cutting step of cutting the plate-like object by adding the value {D + (y−y ′)} calculated in the correction value calculating step to the cutting feed pitch;
A cutting method for a plate-like object comprising:

Images