JP2011104668A - Method for controlling consumption amount of cutting blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling consumption amount of a cutting blade in a cutting device with the cutting blade capable of always continuing cutting. <P>SOLUTION: This method is used in the cutting device including first and second chuck tables. The method includes a first cutting process for holding and cutting a wafer on the first chuck table, a second cutting process for holding and cutting a wafer on the second chuck table, a consumption amount calculating process for positioning the first chuck table just under a depth detection means by utilizing time while the second cutting process is executed, detecting a depth of a cut groove formed in the wafer by the depth detection means and calculating the consumption amount of the cutting blade from the detected groove depth, and a position correcting process for correcting an origin position of a height direction of the cutting blade based on the consumption amount of the cutting blade. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cutting blade consumption control method in a cutting apparatus.

  Various 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. The processing of these electronic parts requires precise cutting in micron units, and not only the chip size but also the cutting depth is important.

  For example, a semiconductor wafer is fixed to a dicing tape, and a cutting blade is cut into the dicing tape by about 10 to 30 μm to completely cut the semiconductor wafer. However, if the cutting amount into the dicing tape is not sufficient, the wafer is cut incompletely. Thus, the lower cut edge is notched.

  In addition, the cutting blade used for cutting has a property of being consumed (abraded) as it is cut, and it is necessary to correct the cutting depth variation due to the consumption of the cutting blade as needed.

  Such variations in the cutting edge position of the cutting blade are detected as needed by a position detection means called an optical sensor (optical setup), and the height position of the cutting blade is corrected (origin position correction) based on the detection result. (For example, see Japanese Patent Application Laid-Open No. 11-214334). With this technique, it is possible to easily detect the height position of the cutting blade without damaging the cutting blade without cutting the chuck table for fixing the workpiece or the workpiece.

  Moreover, in the cutting apparatus, there is a history of improving how efficiently a workpiece can be processed, and the number of cutting means that was originally one becomes two (see, for example, Japanese Patent No. 3493282), Alternatively, there are two chuck tables that were originally one (see, for example, Japanese Patent No. 3765265).

JP-A-11-214334 Japanese Patent No. 3493282 Japanese Patent No. 3765265

  However, even with a cutting device having a plurality of cutting means and / or chuck tables, the conventional optical setup method in which the fluctuation of the cutting edge position of the cutting blade is detected by an optical sensor requires the cutting with the cutting blade to be stopped during setup. The problem to be solved was found that there was room for improvement from the viewpoint of cutting efficiency.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a cutting blade consumption control method in a cutting apparatus in which the cutting blade can always perform cutting. is there.

  According to the present invention, the first chuck table for holding the wafer, the first processing feed means for processing and feeding the first chuck table in the X-axis direction, and the wafer disposed independently of the first chuck table are provided. The second chuck table to be held, the second machining feed means for machining and feeding the second chuck table in the X-axis direction, and the first chuck table or the wafer held on the second chuck table to act on the cutting. Cutting means provided with a cutting blade to be applied; index feeding means for indexing and feeding the cutting means in the Y-axis direction perpendicular to the X-axis direction; and the cutting means in the Z-axis direction perpendicular to the X-axis direction and the Y-axis direction A cutting feed means for cutting and feeding, and a wafer disposed at a position away from the cutting means in the X-axis direction and held by the first chuck table or the second chuck table; A cutting blade consumption control method in a cutting apparatus comprising a depth detecting means for detecting a depth of a cutting groove formed in the wafer, the wafer held on the first chuck table being cut A first cutting step of cutting by the means, a second cutting step of cutting the wafer held on the second chuck table by the cutting means, and a time during the execution of the second cutting step Then, the first machining feed means is operated to position the first chuck table directly below the depth detection means, and the depth detection means detects the depth of the cutting groove formed in the wafer, A consumption amount calculating step for calculating the consumption amount of the cutting blade from the detected groove depth, and the cutting feed means of the cutting means based on the consumption amount of the cutting blade calculated from the consumption amount calculation step. Actuated Consumption management method of the cutting blade in the cutting device for the position correction step of correcting the origin position of the Z-axis direction of the cutting blade, characterized by comprising a Te is provided.

  Preferably, according to the cutting blade consumption amount management method, the sum of the consumption amounts calculated up to the previous time and the addition value of the cutting blade consumption amount calculated in the consumption amount calculation step is a predetermined cutting blade usable limit. If it exceeds the maximum consumable amount that is the criterion of the above, it further includes a limit judgment step for stopping the use of the cutting blade.

  According to the present invention, the consumption of the cutting blade can be managed by using the cutting groove of the workpiece without using an optical sensor. Therefore, even in a cutting apparatus having a plurality of chuck tables, a conventional optical setup is possible. It is possible to always continue the cutting process that must be interrupted, and to provide a very efficient cutting apparatus.

1 is a perspective view of a cutting apparatus to which a cutting blade consumption control method of the present invention is applicable. It is a top view of a cutting device. It is a principal part 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 this schematic diagram which shows the reference position setting process of an imaging means. It is explanatory drawing of the depth detection process of the cutting groove of 1st Embodiment of this invention. It is explanatory drawing which shows the positional relationship of an imaging means and a laser pointer. It is a partial cross section side view of the cutting device which shows a 1st reference position setting process. It is a figure which shows the captured image of a 2nd reference position setting process. FIG. 10A is an explanatory diagram showing a state in which the laser beam irradiation point is deviated from the second reference position, and FIG. 10B is a diagram showing a captured image at that time. FIG. 11A is an explanatory diagram showing a state in which the laser beam irradiation point matches the second reference position, and FIG. 11B is a diagram showing a captured image at that time. It is explanatory drawing which shows the picked-up image in a reference | standard position matching process, Comprising: It is a figure which shows the state which matched the laser beam irradiation point to the cutting-groove bottom after rotating a chuck table (theta) degree.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a cutting apparatus 2 to which the cutting blade consumption control method of the present invention can be applied. FIG. 2 is a plan view thereof, and FIG. 3 is a perspective view of an essential part thereof.

  Hereinafter, the configuration of the cutting apparatus 2 will be described mainly with reference to the perspective view of the main part of FIG. The cutting device 2 includes two pairs of guide rails 6 and 6 a that are mounted on the stationary base 4 and extend in the X-axis direction.

  Reference numeral 8 denotes a first X-axis moving block. The first X-axis moving block 8 is moved in the machining feed direction, that is, the X-axis direction by a first X-axis feed mechanism 14 including a ball screw 10 and a pulse motor 12.

  A first chuck table 18 is mounted on the first X-axis moving block 8 via a cylindrical support member 16. Reference numeral 19 denotes a clamper. A motor that rotates the first chuck table 18 is accommodated in the cylindrical support member 16.

  Although not particularly illustrated, the first chuck table 18 has an adsorption portion formed of porous ceramics and the like, and a frame formed of a metal such as SUS surrounding the adsorption portion. The suction surface (holding surface) of the suction portion and the upper surface of the frame are formed flush with each other. Reference numeral 20 denotes a waterproof cover.

  Reference numeral 8a denotes a second X-axis movement block. The second X-axis movement block 8a is moved in the machining feed direction, that is, the X-axis direction by a second X-axis feed mechanism 14a including a ball screw 10a and a pulse motor 12a.

  A second chuck table 18a is mounted on the second X-axis moving block 8a via a cylindrical support member 16a. 19a is a clamper. A motor for rotating the second chuck table 18a is accommodated in the cylindrical support member 16a.

  Similar to the first chuck table 18, the second chuck table 18 a has a suction portion formed of porous ceramics and the like, and a frame body formed of metal such as SUS surrounding the suction portion. The suction surface (holding surface) of the suction portion and the upper surface of the frame are formed flush with each other. Reference numeral 20a denotes a waterproof cover.

  A gate column 22 is erected on the stationary base 4. A pair of guide rails 24 extending in the Y-axis direction are fixed to the front side of the portal column 22. The first Y-axis moving block 26 is moved in the Y-axis direction by a first Y-axis feed mechanism 32 including a ball screw 28 and a pulse motor 30.

  The first Y-axis moving block 26 is formed with a pair of guide rails 34 extending in the Z-axis direction. The integrated first imaging means 42 and first laser irradiation means 44 are moved in the Z-axis direction by a first Z-axis feed mechanism 40 including a ball screw 36 and a pulse motor 38.

  A second Y-axis moving block 26a is moved in the Y-axis direction along the pair of guide rails 24 by a second Y-axis feed mechanism 32a including a ball screw 28a and a pulse motor 30a.

  The second Y-axis moving block 26a is formed with a pair of guide rails 34a extending in the Z-axis direction. The integrated second imaging means 42a and second laser irradiation means 44a are moved in the Z-axis direction by a second Z-axis feed mechanism 40a composed of a ball screw 36a and a pulse motor 38a.

  As shown in FIG. 8, a pair of guide rails 48 extending in the Y-axis direction are also formed on the back side of the portal column 22. The third Y-axis moving block 46 is moved in the Y-axis direction by a third Y-axis feed mechanism (index feed mechanism) 54 including a ball screw 50 and a pulse motor.

  A pair of guide rails (not shown) are formed on the back surface of the third Y-axis moving block 46, and a first Z-axis moving block 56 includes a ball screw 58 and a pulse motor 60. Is moved in the Z-axis direction.

  As shown in FIG. 8, the first cutting unit 64 is formed integrally with the first Z-axis moving block 56, and the first cutting unit 64 is movable in the Y-axis direction and the Z-axis direction. The first cutting unit 64 includes a spindle 66 that is rotationally driven by a motor (not shown), and a first cutting blade 68 that is attached to the tip of the spindle 66.

  A fourth Y-axis feed block (index feed mechanism) 54a is configured such that a fourth Y-axis moving block 46a includes a ball screw and a pulse motor 52a along a pair of guide rails 48 formed on the back side of the portal column 22. Is moved in the Y-axis direction.

  A pair of guide rails (not shown) are formed on the back surface of the fourth Y-axis moving block 46a, and the second Z-axis moving block 56a is formed by a fourth Z-axis moving mechanism 62a composed of a ball screw and a pulse motor 60a. It is moved in the Z-axis direction.

  A second cutting unit similar to the first cutting unit 64 is formed integrally with the second Z-axis moving block 56a, and the second cutting unit is movable in the Y-axis direction and the Z-axis direction. The second cutting unit includes a spindle that is rotationally driven by a motor, and a second cutting blade that is attached to the tip of the spindle. The pulse motors 12, 12a, 30, 30a, 60, 60a are connected to the control means 70 shown in FIG.

  In the cutting apparatus 2 of the present embodiment, the first chuck table 18 and the second chuck table 18a are independently moved in the X-axis direction. Further, the integrated first imaging unit and first laser irradiation unit 44 and the first cutting unit 64 are independently moved in the Y-axis direction and the Z-axis direction. Further, the integrated second imaging means 42a and second laser irradiation means 44a and the second cutting unit are independently moved in the Y-axis direction and the Z-axis direction.

  Although not particularly illustrated, the first imaging unit 42 and the second imaging unit 42a each include a microscope having an objective lens and a CCD camera that captures an enlarged image of the microscope. The microscope is controlled to be switchable between a high magnification and a low magnification.

  Referring to FIG. 1, reference numeral 51 denotes a cassette that accommodates the wafer W shown in FIG. 4, and a plurality of wafers W are accommodated in the cassette 51. A gate frame 53 is erected on the stationary base 4.

  A guide rail 55 is attached to the front surface of the portal frame 53, and a wafer carry-in / out means 57 is attached along the guide rail 55 so as to be movable in the Y-axis direction. Reference numeral 59 denotes a spinner cleaning device for cleaning the wafer W after the cutting process.

  As shown in FIG. 4, the first street S1 and the second street S2 are formed orthogonal to each other on the surface of the semiconductor wafer W that is a processing target of the cutting device 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 sucked and held by the first chuck table 18 or the second chuck table 18a in this state.

  In order to implement the cutting blade consumption control method of the present invention, it is necessary to first perform an origin position detection step of detecting the origin positions of the first cutting blade 68 and the second cutting blade. This origin position detection step must be performed whenever a new chuck table 18 or 18a is mounted or when the chuck table 18 or 18a is disassembled and reassembled after cleaning.

  In this origin position detection step, the first cutting blade 68 is cut into the frame of the first chuck table 18 and the second chuck table 18a to establish conduction, and thereby the first chuck table 18 of the first cutting blade 68 and Each of the origin positions with respect to the second chuck table 18a is detected, and this origin position is stored in the memory of the control means 70 of the cutting device 2.

  Similarly, in the origin position detection process of the second cutting blade, the second cutting blade is cut into the frames of the first chuck table 18 and the second chuck table 18a to establish conduction, whereby the first cutting blade first position is detected. This is carried out by detecting the origin positions for the chuck table 18 and the second chuck table 18a, respectively, and storing the origin positions in the memory of the control means 70 of the cutting apparatus 2.

  Prior to the cutting blade consumption management method of the present invention, when a new cutting blade is mounted on the spindle, the diameter of the cutting blade is known. The height of the cutting blade when cutting the wafer W held on the chuck table 18a, that is, the height of the bottom of the cutting groove is calculated.

  Then, the wafer W supported by the annular frame F is sucked and held on the first chuck table 18 or the second chuck table 18a via the dicing tape T as shown in FIG. 4, and the third Z-axis feed mechanism 62 is operated. The cutting blade 68 is positioned at the calculated height, and the cutting of the wafer W is started.

  The cutting blade wear amount management method of the present invention includes a first cutting step of sucking and holding the wafer W on the first chuck table 18 and cutting the wafer W with the first cutting blade 68 or the second cutting blade; And a second cutting step in which the wafer W is sucked and held on the second chuck table 18a and the wafer W is cut by the first cutting blade 68 or the second cutting blade.

  Further, by using the time when the second cutting process is performed, the first X-axis feed mechanism 14 is operated to bring the first chuck table 18 directly below the first imaging means 42 which is a height detection means. A consumption amount calculating step is included in which the depth of the cutting groove formed in the wafer W is detected by the first imaging means 42 and the consumption amount of the first cutting blade 68 is calculated from the detected groove depth. This cutting groove depth detection step includes a first embodiment and a second embodiment described below.

  Prior to the cutting groove depth detection step of the first embodiment, first, as shown in FIG. 5, the focus 76 of the imaging means 42 at the time of high magnification is set on the holding surface 21 of the chuck table 18, and the imaging means at this time The height of 42 is stored in the memory of the control means 70 as the reference position of the imaging means 42.

  Then, after the wafer W is appropriately cut by the cutting blade 68, in the first embodiment of the present invention, the first Z-axis feed is performed so that the focal point 76 of the imaging means 42 matches the cutting groove bottom 61 as shown in FIG. The pulse motor 38 of the mechanism 40 is driven, and the height position of the Z-axis of the imaging means 42 at this time is stored in the memory of the control means 70 (groove bottom height detection step).

  From the difference between the position of the imaging means 42 in the Z-axis direction in the groove bottom height detection process performed last time and the position of the imaging means 42 in the Z-axis direction in the groove bottom height detection process performed this time, the cutting blade 68 A consumption amount is calculated (consumption amount calculation step).

  Based on the consumption amount of the cutting blade 68 calculated from the consumption amount calculation step, the pulse motor 60 of the third Z-axis feed mechanism 62 is driven to correct the origin position of the cutting blade 68 in the Z-axis direction.

  The sum of the amount of wear calculated up to the previous time and the amount of wear of the cutting blade 68 calculated in the step of calculating the amount of wear exceed the maximum consumable amount that serves as a reference for a predetermined usable limit of the cutting blade 68. In such a case, the cutting blade 68 is stopped and replaced with a new cutting blade.

  In the above description, the amount of consumption of the first cutting blade 68 is managed using the first imaging means 42, but the amount of consumption of the second cutting blade (not shown) is similarly determined using the first imaging means 42. Can be managed. Further, even when the second imaging means 42a is used, the consumption amount of the first cutting blade 68 or the second cutting blade (not shown) can be managed.

  Next, a groove depth detection method according to the second embodiment of the present invention will be described with reference to FIGS. Referring to FIG. 7, a diagram showing the positional relationship between the imaging means 42 and the laser pointer 72 is shown. In the groove depth (the height of the cutting groove in the Z-axis direction) detection method of the present embodiment, the positional relationship between the focal point 76 of the imaging means 42 and the laser pointer 72 is used.

  Reference numeral 76 denotes a focal point of the image pickup means 42. The laser pointer 72 of the laser irradiation means 44 has a laser beam 74 emitted from the laser pointer 72 inclined at an angle α with respect to a horizontal plane (the holding surface 21 of the chuck table 18). It is attached so as to pass through the focal point 76 of the imaging means 42.

  However, since it is difficult to adjust the laser pointer 72 so that the laser beam 74 completely coincides with the focal point 76 of the imaging means 42, the point where the laser beam 74 emitted from the laser pointer 72 is as close as possible to the focal point 76. Set to pass.

  Referring to FIG. 8, there is shown a partial cross-sectional side view of the cutting apparatus showing the first and second reference position setting steps of the present embodiment. FIG. 9 shows the beam of the laser beam 74 emitted from the laser pointer 72. The captured image 82 when the spot is at the second reference position is shown.

  In the groove depth detection method of the present embodiment, first, in the height direction (Z-axis direction) of the image pickup means 42 when the microscope is focused on the holding surface 21 of the chuck table 18 at the time of high magnification. A first reference position setting step for storing the position as the first reference position in the memory of the control means 70 is performed.

  Next, when the first imaging means 42 is at the first reference position, the laser pointer 72 irradiates the holding surface 21 of the chuck table 18 with a laser beam 74 inclined by a predetermined angle α and is held by the first imaging means 42. The beam spot 84 on the surface 21 is imaged. Then, as shown in FIG. 9, the coordinate position (X1, Y1) of the beam spot 84 in the captured image 82 is stored as the second reference position P1 (second reference position setting step).

  Then, after the wafer W is appropriately cut by the cutting blade 68, as shown in FIG. 10A, a laser beam 74 is irradiated from the laser pointer 72 at a predetermined angle α, and the beam is applied to the bottom surface 86a of the cutting groove 86. A spot P2 is formed. A captured image 82 at this time is shown in FIG.

  Since the beam spot P2 does not coincide with the focal point 76 of the first imaging means 42, the coordinates (X2, Y2) of the beam spot P2 are shifted from the second reference position P1 shown in FIG. Here, the X axis in the captured image 82 is parallel to the cutting groove 86, and the Y axis is orthogonal to the X axis.

  Therefore, the first image pickup means 42 and the laser pointer 72 are raised by driving the first Z-axis feed mechanism 40 until the focal point 76 of the first image pickup means 42 coincides with the bottom surface 86a of the cutting groove 86, as shown in FIG. As shown, the beam spot of the laser beam 74 is made to coincide with the focal point 76.

  At this time, the coordinate position (X2, Y2) of the beam spot P2 coincides with the coordinate (X1, Y1) of the second reference position P1 in the captured image 82 as shown in FIG. The height position in the Z-axis direction of the first imaging means 42 at this time is stored in the memory of the control means 70 of the cutting device 2.

  The beam spot forming step and the reference position matching step are preferably performed periodically. The position of the first imaging unit 42 in the Z-axis direction after the previous reference position matching step and the current reference position matching step after this time The consumption amount of the first cutting blade 68 is calculated from the difference in the position of the first imaging means 42 in the Z-axis direction (consumption amount calculation step).

  Based on the consumption amount of the first cutting blade 68 calculated from the consumption amount calculation step, the pulse motor 60 is driven to correct the origin position of the first cutting blade 68 in the Z-axis direction. In addition, the maximum consumption that the sum of the consumption amounts calculated up to the previous time and the addition amount of the consumption amount of the first cutting blade 68 calculated this time becomes a reference for the predetermined usable limit of the first cutting blade 68. When it exceeds the possible amount, it is determined that the first cutting blade 68 is at the usable limit, and the use of the first cutting blade 68 is stopped (limit determination step).

  Due to a mounting error of the laser pointer 72 or the like, the laser beam 74 emitted from the laser pointer 72 may form a beam spot at a position outside the cutting groove 86 without forming a beam spot in the cutting groove 86.

  Therefore, in the reference position matching step of the present embodiment, the coordinate position (X3, Y3) of the beam spot P3 of the laser beam 74 emitted from the laser pointer 72 is always in the cutting groove 86 in the captured image 82 as shown in FIG. Therefore, the first chuck table 18 is rotated by an angle θ calculated from the relationship of tan θ = Y3 / X3.

  Thus, by rotating the first chuck table 18 by θ, the cutting groove 86 rotates by θ, and the laser beam 74 irradiated from the laser pointer 72 can always be guided into the cutting groove 86. Since the θ-axis rotation angle of the first chuck table 18 becomes an angle unique to the apparatus if the laser pointer 72 is fixed, once it is determined, the angle can always be corrected using that angle.

  The cutting apparatus 2 shown in FIGS. 1 to 3 includes two imaging means 42 and 42a and two cutting blades. In order to implement the cutting blade consumption management method of the present invention, imaging is performed. A cutting device having one means and one cutting blade is also possible. In this case as well, the effects of the present invention described in the column of the effects of the present invention can be similarly achieved.

2 Cutting device 14 1st X-axis feed mechanism 14a 2nd X-axis feed mechanism 18 1st chuck table 18a 2nd chuck table 32 1st Y-axis feed mechanism 32a 2nd Y-axis feed mechanism 42 1st image pickup means 42a 1st image pickup means 44 1st Laser irradiation means 44a Second laser irradiation means 54 Third Y-axis feed mechanism 54a Fourth Y-axis feed mechanism 62 First Z-axis feed mechanism 62a Second Z-axis feed mechanism 64 First cutting unit 68 First cutting blade 72 Laser pointer 74 Laser beam 76 Focus 82 Captured image 86 Cutting groove

Claims (2)

A first chuck table for holding a wafer, a first processing feed means for processing and feeding the first chuck table in the X-axis direction, and a second chuck for holding a wafer disposed independently of the first chuck table A table, a second machining feed means for machining and feeding the second chuck table in the X-axis direction, and a cutting blade that acts on the first chuck table or the wafer held by the second chuck table to perform cutting. Cutting means, indexing feeding means for indexing and feeding the cutting means in the Y-axis direction orthogonal to the X-axis direction, and cutting feed for cutting and feeding the cutting means in the X-axis direction and the Z-axis direction perpendicular to the Y-axis direction And a wafer held at the first chuck table or the second chuck table and disposed at a position away from the cutting means in the X-axis direction. And depth detecting means for detecting the depth of Kezumizo, a consumption management method of the cutting blade in the cutting device provided with,
A first cutting step of cutting the wafer held on the first chuck table by the cutting means;
A second cutting step of cutting the wafer held on the second chuck table by the cutting means;
Using the time during the execution of the second cutting step, the first machining feed means is operated to position the first chuck table directly below the depth detection means, and the depth detection means A consumption amount calculating step of detecting a depth of the cutting groove formed in the wafer and calculating a consumption amount of the cutting blade from the detected groove depth;
A position correcting step of operating the cutting feed means of the cutting means based on the consumed amount of the cutting blade calculated from the consumed amount calculating step to correct the origin position of the cutting blade in the Z-axis direction;
A method for managing the amount of wear of a cutting blade in a cutting apparatus.   The sum of the consumed amounts calculated up to the previous time and the added value of the consumed amount of the cutting blade calculated in the consumed amount calculating step is the maximum consumable amount that serves as a reference for the predetermined usable limit of the cutting blade. The method for managing the amount of wear of the cutting blade in the cutting apparatus according to claim 1, further comprising a limit determination step of stopping the use of the cutting blade when the amount exceeds the upper limit.

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