JP2014116487A - Cutting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting device which is adaptive to various devices and various cutting methods.SOLUTION: A cutting device includes a chuck table 6, cutting means 42, 42a of cutting a workpiece, imaging means of imaging the workpiece 11, and a back pressure sensor 47 which detects a height position of a top surface of the workpiece 11. The imaging means includes visible light imaging means and infrared imaging means. The back pressure sensor 47 includes an air jet nozzle 48 which jets compressed air to the workpiece 11, a compressed air supply source 58 which supplies compressed air to the air jet nozzle 48, a first path which connecting the air jet nozzle 48 and compressed air supply source 58 to each other, a second path which is connected to the compressed air source 58 and releases compressed air, a differential pressure sensor 68 which is connected to the first path and second path, and outputs a voltage corresponding to differential pressure between the pressure of the first path and the pressure of the second path, and a control part 70 which recognizes the voltage value that the differential pressure sensor 68 outputs.

Description

  The present invention relates to a cutting apparatus for cutting a workpiece such as a wafer.

  Semiconductor wafers in which multiple devices such as IC and LSI are formed on a silicon substrate, and various ceramic substrates, resin substrates, glass substrates, etc. used for electronic components are individually chipped by a dicing machine (cutting machine). The divided chips are widely used in various electric devices.

  In the cutting device, cutting is performed by cutting a cutting blade including superabrasive grains mounted on the tip of a spindle into a workpiece such as a wafer while rotating at high speed. 2. Description of the Related Art In recent years, a cutting apparatus having two spindles has been proposed in order to increase the productivity of cutting work or to perform step cut for performing high-precision cutting.

  In step cutting, a cutting groove having a predetermined depth is formed with a first cutting blade, and then the wafer is divided into individual chips by cutting the center of the bottom of the cutting groove with a second cutting blade. In step cutting, a wafer with a predetermined thickness is cut twice, so that the amount of cutting when cutting with each cutting blade is compared to the method of cutting with one cutting blade at a time (single cut) It is possible to reduce the processing load at the time of cutting and to perform cutting with good processing quality.

  In semiconductor wafer cutting, various devices and various cutting methods according to the devices have been proposed in recent years. Examples thereof include a predicing method (dicing before grinding) and edge trimming.

  In the first dicing method, after forming a groove having a depth corresponding to the finished thickness of the device on the surface of the semiconductor wafer, the back surface of the wafer is ground to expose the cutting groove on the back surface, and the wafer is divided into individual device chips. To divide.

  Therefore, since the cutting depth is very important in the tip dicing method, a back pressure sensor that can detect the height position of the upper surface of the wafer with high accuracy is used (see Japanese Patent No. 4675451).

  An SOI (Silicon) in which an oxide film layer with high electrical insulation, which has a high processing demand in normal dicing or edge trimming, is formed inside the wafer, and the two wafers are bonded together via the oxide film layer. In the case of an On Insulator wafer, a pattern formed on the bonding surface may be imaged with an infrared camera to detect the pattern.

Japanese Patent No. 4675451 JP-A-8-107092

  While such various devices and various cutting methods have been proposed, a cutting apparatus capable of handling them has been desired.

  This invention is made | formed in view of such a point, The place made into the objective is to provide the cutting device which can respond to various devices and various cutting methods.

  According to the present invention, there is provided a cutting apparatus, a chuck table for holding a workpiece, a cutting means for cutting the workpiece held on the chuck table, and an image of the workpiece held on the chuck table. Imaging means, and a back pressure sensor for detecting the height position of the surface of the workpiece held on the chuck table, and the imaging means is a visible light imaging means set at a macro magnification and a micro magnification. And an infrared imaging means set to a macro magnification and a micro magnification, and the back pressure sensor supplies an air ejection nozzle that ejects compressed air to the workpiece, and supplies the compressed air to the air ejection nozzle A first path connecting the compressed air supply source, the air ejection nozzle and the compressed air supply source; a second path connected to the compressed air supply source for releasing the compressed air to the atmosphere; and the first path No And a differential pressure sensor connected to the second path and outputting a voltage corresponding to a differential pressure between the pressure of the first path and the pressure of the second path, and a voltage output by the differential pressure sensor And a control unit for recognizing the value.

  Preferably, the cutting means includes a first cutting means and a second cutting means, the visible light imaging means is attached to the first cutting means, and the infrared imaging means is attached to the second cutting means. The back pressure sensor is attached to the first cutting means or the second cutting means.

  The cutting apparatus of the present invention has two spindles and includes visible light imaging means, infrared imaging means, and a back pressure sensor, and therefore can cope with various cutting processes.

It is a perspective view of the cutting device concerning the embodiment of the present invention. It is a top view of the principal part of the cutting device shown in FIG. It is a schematic block diagram of a back pressure type sensor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, a perspective view of a cutting device 2 according to an embodiment of the present invention is shown. The cutting device 2 is a facing dual spindle type cutting device in which two cutting blades are arranged to face each other.

  A chuck table 6 is disposed on the base 4 of the cutting apparatus 2 so as to be reciprocally movable in the X-axis direction by a machining feed mechanism (not shown). The chuck table 6 is configured by arranging a suction holding unit 10 made of porous ceramics or the like in a frame 8 made of metal such as SUS. A water cover 12 is disposed around the chuck table 6, and a bellows 14 is connected to the water cover 12 and the base 4.

  The workpiece 11 is mounted on the chuck table 6 with the outer peripheral portion attached to the dicing tape T attached to the annular frame F, and is sucked through the dicing tape T by the suction holding portion 10 of the chuck table 6. Retained.

  A gate-shaped column 20 is erected on the rear side of the base 4. A pair of guide rails 22 extending in the Y-axis direction are fixed to the column 20. A first Y-axis moving block 24 is mounted on the column 20 along the guide rail 22 so as to be movable in the Y-axis direction by a Y-axis moving mechanism 30 including a ball screw 26 and a pulse motor (not shown).

  A pair of guide rails 32 extending in the Z-axis direction are fixed to the first Y-axis moving block 24. On the first Y-axis movement block 24, a first Z-axis movement block 34 is mounted on the guide rail 32 by a first Z-axis movement mechanism 40 including a ball screw 36 and a pulse motor 38 so as to be movable in the Z-axis direction. ing.

  A first cutting unit 42 and a first alignment unit 44 are attached to the first Z-axis moving block 34. A spindle housing 46 accommodates the spindle of the first cutting unit 42.

  An air ejection nozzle 48 of a back pressure sensor 47 is attached to the first alignment unit 44. As shown in FIG. 2, the first alignment unit 44 includes a visible light imaging unit 54 having a macro microscope 50 and a micro microscope 52.

  Further, a second Y-axis moving block 24a is mounted on the portal column 20 so that it can be moved in the Y-axis direction by being guided by the guide rail 22 by a second Y-axis moving mechanism 30a comprising a ball screw 26a and a pulse motor 28a. .

  A pair of guide rails 32a extending in the Z-axis direction are fixed to the second Y-axis moving block 24a. On the second Y-axis moving block 24a, a second Z-axis moving block 34a is mounted on the guide rail 32a by a second Z-axis moving mechanism 40a including a ball screw 36a and a pulse motor 38a so as to be movable in the Z-axis direction. Yes.

  A second cutting unit 42a and a second alignment unit 44a are attached to the second Z-axis moving block 34a. A spindle housing 46a accommodates the spindle of the second cutting unit 42a.

  As shown in FIG. 2, the second alignment unit 44a includes an infrared imaging means 54a having a macro microscope 50a and a micro microscope 52a. As shown in FIG. 1, the air ejection nozzle 48 of the back pressure sensor 47 is attached to the first alignment unit 44, but the first alignment unit 44 is fixed to the first Z-axis moving block 34. In the configuration diagram of the back pressure sensor 47 shown in FIG. 3, it is assumed that the air ejection nozzle 48 is fixed to the first Z-axis moving block 34.

  As shown in FIG. 3, the back pressure sensor 47 includes an air ejection nozzle 48 that blows air downward. The air ejection nozzle 48 is supported by the first Z-axis moving block 34, and a nut built in the first Z-axis moving block 34 is screwed into a ball screw 36 disposed in the vertical direction (Z-axis direction). The screw 36 is connected to a pulse motor 38 and is rotated by the pulse motor 38. That is, when the pulse motor 38 is driven, the ball screw 36 rotates and the air ejection nozzle 48 supported by the first Z-axis moving block 34 moves in the vertical direction.

  The air ejection nozzle 48 is connected to a compressed air supply source 58 via an air supply pipe 56. The air supply pipe 56 is provided with an orifice 60, and the compressed air from the compressed air supply source 58 is throttled by the orifice 60 and supplied to the air ejection nozzle 48. The compressed air supply source 58 further communicates with the atmosphere via an air release pipe 62. The air release pipe 62 is provided with a fixed orifice 64 and a variable orifice 66.

  Compressed air is supplied from the compressed air supply source 58 at an equal rate to the air supply pipe 56 and the air release pipe 62, and the compressed air supplied to the air release pipe 62 is released to the atmosphere via the variable orifice 66. It has a configuration.

  Further, the air supply pipe 56 and the air release pipe 62 are connected via a differential pressure sensor 68 that measures a differential pressure generated between the compressed air flowing through the air supply pipe 56 and the compressed air flowing through the air release pipe 62. It is connected. The differential pressure sensor 68 and the pulse motor 38 are connected to the control means 70, and the control means 70 drives the pulse motor 38 based on the differential pressure detected by the differential pressure sensor 68.

  The differential pressure sensor 68 has a diaphragm to which a strain gauge is attached, and a strain corresponding to the differential pressure generated when compressed air is ejected from the air ejection nozzle 48 onto the workpiece 11 held on the chuck table 6. The gauge strain is measured as a voltage.

  The relationship between the distance Z2 from the upper surface of the workpiece 11 held on the chuck table 6 to the lower end of the air ejection nozzle 48 and the voltage output from the differential pressure sensor 68 is stored in advance in the control means 70 as a map.

  Z1 is the distance from the surface of the chuck table 6 to the lower end of the air ejection nozzle 48. This distance Z1 is a pulse motor required to raise the air ejection nozzle 48 to the illustrated position with the surface of the chuck table 6 as the origin position. Detection is possible with 38 pulses.

  In order to measure the thickness of the workpiece 11, the voltage when the compressed air is ejected from the air ejection nozzle 48 onto the surface of the workpiece 11 is measured. The distance Z2 from the surface of 11 to the lower end of the air ejection nozzle 48 is obtained. And the thickness of the to-be-processed object 11 is computable by Z1-Z2.

  The details of the back pressure sensor 47 are described in Japanese Patent Application Laid-Open No. 2001-298003. Therefore, in this specification, the contents of this publication are incorporated as references.

  In the embodiment described above, the air ejection nozzle 48 of the back pressure sensor 47 is mounted on the first cutting unit 42, but the air ejection nozzle 48 may be mounted on the second cutting unit 42a.

2 Cutting device 6 Chuck table 11 Work piece 42 First cutting unit 42a Second cutting unit 47 Back pressure sensor 48 Air jet nozzle 50, 50a Macro microscope 52, 52a Micro microscope 54 Visible light imaging means 54a Infrared imaging means 56 Compressed air Supply pipe 58 Compressed air supply source 62 Compressed air release pipe 68 Differential pressure sensor

Claims (2)

A cutting device,
A chuck table for holding the workpiece;
Cutting means for cutting a workpiece held on the chuck table;
Imaging means for imaging the workpiece held on the chuck table;
A back pressure sensor for detecting the height position of the surface of the workpiece held by the chuck table,
The imaging means includes visible light imaging means set to macro magnification and micro magnification, and infrared imaging means set to macro magnification and micro magnification,
The back pressure sensor
An air ejection nozzle for ejecting compressed air to the workpiece;
A compressed air supply source for supplying compressed air to the air ejection nozzle;
A first path connecting the air ejection nozzle and the compressed air supply source;
A second path connected to the compressed air supply source to release the compressed air to the atmosphere;
A differential pressure sensor connected to the first path and the second path and outputting a voltage corresponding to a differential pressure between the pressure of the first path and the pressure of the second path;
A controller for recognizing the voltage value output by the differential pressure sensor;
The cutting device characterized by including. The cutting means includes a first cutting means and a second cutting means,
The visible light imaging means is attached to the first cutting means; the infrared imaging means is attached to the second cutting means;
The cutting apparatus according to claim 1, wherein the back pressure sensor is attached to the first cutting means or the second cutting means.

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