JP2010123823A - Cutting device - Google Patents

Abstract

A cutting device capable of efficiently removing whisker-like debris generated from a die attach film during cutting is provided.
A chuck table T for holding a wafer W, a cutting means including a cutting blade 28 for cutting the wafer held by the chuck table, and the chuck table and the cutting means are relatively fed in a cutting direction. A cutting device provided with a cutting feed means that includes a groove cleaning nozzle 33 that injects a thread-like cleaning water 37 into the cutting groove 56 immediately after being cut by the cutting blade. Yes. The whisker-like debris 58 generated by cutting the die attach film 29 is removed by the cleaning water 37 sprayed from the groove cleaning nozzle 33.
[Selection] Figure 6

Description

  The present invention relates to a cutting apparatus suitable for dividing a semiconductor wafer having a die attach film attached to the back surface into individual devices.

  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 (dicing device) to be divided into individual devices, and the divided devices are used for electric devices such as mobile phones and personal computers.

  The device divided from the semiconductor wafer is bonded to a lead frame by a die bonding adhesive film called a die attach film (DAF), and further packaged.

  The DAF is affixed to the back surface of the semiconductor wafer, and when the wafer is divided into individual devices, the DAF is divided together with the wafer to form a device integrated with the DAF (see, for example, JP-A-2005-56968). .

  However, DAF is composed of epoxy resin, etc. When cutting DAF together with the wafer with a cutting blade, whisker-like debris (flash) is generated, and whisker-like debris is scattered when the device is picked up from the dicing tape. There is a problem that it adheres to the bonding pad and causes wire breakage when wire bonding with the electrode of the lead frame, thereby degrading the quality of the device.

As a method for solving this problem, Japanese Patent Application Laid-Open No. 2004-79597 reduces whiskers by blowing hot air to the DAF before the die bonding process or by heating the DAF in contact with the heating means. Thus, there has been proposed a technique for eliminating the adverse effect of whiskers on the wire bonding process.
JP 2005-56968 A JP 2004-79597 A

  The semiconductor chip processing method disclosed in Patent Document 2 is effective in reducing whisker-like debris extending from the cut DAF, but it is necessary to add a heat treatment process before the die bonding process, There is a problem that the efficiency is lowered.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a cutting apparatus capable of removing whisker-like debris extending from a DAF cut with a wafer without causing a reduction in production efficiency. Is to provide.

  According to the present invention, a chuck table for holding a wafer, a cutting means including a cutting blade for cutting the wafer held by the chuck table, and a cutting for relatively cutting and feeding the chuck table and the cutting means in a cutting direction. A cutting device comprising a feeding means, wherein the cutting means is provided with a groove cleaning nozzle for injecting thread-like cleaning water into a cutting groove immediately after being cut by the cutting blade. A cutting device is provided.

  Preferably, the groove cleaning nozzle ejects cleaning water having a flow rate of 50 to 100 m / sec.

  The cutting device of the present invention has a groove cleaning nozzle that ejects thread-like cleaning water into a cutting groove immediately after cutting with a cutting blade and discharges beard-like debris extending from the DAF from the cutting groove. The scraps can be efficiently removed, and even when the device is picked up from the dicing tape, whiskers are not scattered and the quality of the device is not deteriorated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an external perspective view of a cutting apparatus 2 that can dicate a semiconductor wafer and divide it 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.

  A die attach film (DAF) 29 formed of an epoxy resin or the like is attached to the back surface of the wafer W, and the DAF 29 side of the wafer W is attached to a dicing tape T that is an adhesive tape. Is attached to the 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 22 that images the surface of the wafer W, and can detect a street to be cut by a process 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, in which a spindle 26 that is rotationally driven by a servo motor (not shown) is rotatably accommodated. 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 thereof.

  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.

  The blade cover 30 is further provided with a groove cleaning nozzle 33 for injecting thread-like high-speed cleaning water into the cutting groove of the wafer W cut by the cutting blade 28. Washing water is supplied to the groove cleaning nozzle 33 through the pipe 35.

  Reference numeral 50 denotes a blade detection block incorporating a blade sensor for detecting chipping or wear of the cutting blade 28a of the cutting blade 28. By inserting a screw 54 through the round hole 52 and screwing it into the screw hole 38 of the blade cover 30. The blade detection block 50 is attached to the blade cover 30. The blade detection block 50 has an adjustment screw 55 for adjusting the position of the blade sensor.

  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. When replacing the cutting blade 28, the detachable cover 40 is removed from the blade cover 30, and the cutting blade 28 is replaced in this state.

  In the cutting apparatus 2 configured as described above, the wafer W accommodated in the wafer cassette 8 is sandwiched by the frame F by the loading / unloading means 10, and the loading / unloading means 10 moves to the rear of the apparatus (Y-axis direction). When the nipping is released in the placing area 12, the placing area 12 is placed in the temporary placing area 12. Then, the wafer W is positioned at a certain position by the positioning means 14 moving in a direction approaching each other.

  Next, the frame F is adsorbed by the conveyance means 16, and the wafer W integrated with the frame F is conveyed to the chuck table 18 by the rotation of the conveyance means 16 and is held by the chuck table 18. Then, the chuck table 18 moves in the X-axis direction, and the wafer W is positioned directly below the alignment means 20.

  The image used for pattern matching at the time of alignment in which the alignment unit 20 detects a street to be cut needs to be acquired in advance before cutting. Therefore, when the wafer W is positioned directly below the alignment unit 20, the imaging unit 22 captures the surface of the wafer W and causes the display unit 6 to display the captured image.

  The operator of the cutting apparatus 2 operates the operation unit 4 to move the image pickup unit 22 slowly and also move the chuck table 18 as necessary to search for a pattern that is a pattern matching target.

  When the operator determines a key pattern, an image including the key pattern is stored in a memory provided in the controller 20 of the cutting apparatus 2. Further, the distance between the key pattern and the center line of the streets S1 and S2 is obtained by a coordinate value or the like, and the value is also stored in the memory.

  Further, by moving the image pickup means 22, an interval between the adjacent streets (street pitch) is obtained by a coordinate value or the like, and the street pitch value is also stored in the memory of the controller.

  At the time of cutting along the street of the wafer W, the alignment unit 20 performs pattern matching between the stored key pattern image and the image actually acquired by the imaging unit 22.

  When the patterns match, the cutting means 24 is moved in the Y-axis direction by the distance between the key pattern and the street center line, thereby aligning the street to be cut with the cutting blade 28.

  While the street to be cut and the cutting blade 28 are aligned, the chuck table 18 is moved in the X-axis direction indicated by arrow X in FIG. 5 and the cutting blade 28 is rotated at high speed in the direction of arrow 28a. When the cutting means 24 is moved down while being moved, the aligned street is cut.

  By performing cutting while feeding the cutting means 24 in the Y-axis direction by the street pitch stored in the memory, all the streets S1 in the same direction are cut. Furthermore, when the chuck table 18 is rotated by 90 ° and then the same cutting as described above is performed, the streets S2 are all cut and divided into individual devices D.

  In the cutting apparatus 2 of the present embodiment, since the groove cleaning nozzle 33 is disposed in the cutting means 24, as shown in FIG. 6, φ0 from the groove cleaning nozzle 33 in the cutting groove 56 immediately after cutting with the cutting blade 28. A thread-like high-speed washing water 37 having a diameter of .05 mm to φ1.0 mm is sprayed to remove the whisker-like debris 58 generated by cutting the DAF 29 from the cutting groove 56. Preferably, the flow rate of the cleaning water 37 sprayed from the groove cleaning nozzle 33 is 50 to 100 m / sec.

  As described above, in the cutting apparatus 2 of the present embodiment, the high-speed cleaning water 37 is sprayed from the groove cleaning nozzle 33 into the cutting groove 56 immediately after cutting by the cutting blade 28, and the whisker-like scraps 58 extending from the DAF 29 are cut into the cutting groove 56. Since it is discharged and removed from inside, the whisker-like debris 58 can be efficiently removed, and even if the device D is picked up from the dicing tape T in the subsequent process, the whisker-like debris does not scatter and the device quality is improved There is no reduction.

It is an external appearance perspective view of a cutting device. It is a perspective view which shows the wafer integrated with the flame | frame. It is a disassembled perspective view of a cutting means. It is a perspective view of a cutting means. It is a perspective view which shows a mode that the wafer supported by the flame | frame is cutting. It is sectional drawing explaining the principal part of this invention.

Explanation of symbols

2 Cutting device 18 Chuck table 24 Cutting means 26 Spindle 28 Cutting blade 29 DAF
33 groove cleaning nozzle 56 cutting groove 58 whiskers

Claims (2)

A chuck table for holding a wafer, a cutting means including a cutting blade for cutting the wafer held by the chuck table, and a cutting feed means for cutting and feeding the chuck table and the cutting means in a cutting direction relatively. Cutting device,
A cutting apparatus characterized in that the cutting means is provided with a groove cleaning nozzle for injecting thread-like cleaning water into a cutting groove immediately after being cut by the cutting blade.   The cutting apparatus according to claim 1, wherein the groove cleaning nozzle sprays cleaning water having a flow rate of 50 to 100 m / sec.

Images