JP5373496B2 - Cutting groove detecting device and cutting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting groove detection device capable of detecting a cutting groove formed in a wafer through dicing tape from the back side, and to provide a cutting machine with the device. <P>SOLUTION: The device detects the cutting groove, which is formed in a wafer adhered to the surface side of dicing tape mounted on an annular frame by a cutting blade, through dicing tape; comprising an imaging camera, an objective lens holding tube that holds an objective lens arranged on the optical axis of the imaging camera, an imaging means with a water layer forming means that forms a water layer between an object mounted on the upper end of the objective lens holding tube and the imaging means, and a display means that displays an image photographed by the imaging camera of the imaging means. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a cutting groove detection device for detecting a state of a cutting groove in which a workpiece such as a semiconductor wafer is cut by a cutting blade, and a cutting machine equipped with the cutting groove detection device.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual semiconductor devices.

  The above-described cutting along the street of the semiconductor wafer is usually performed by a cutting machine called a dicer. This cutting machine includes a chuck table for holding a workpiece such as a wafer, a cutting means having a cutting blade for cutting the workpiece held on the chuck table, and the chuck table. And an alignment unit having an optical system for detecting a cutting area of the workpiece.

  In such a cutting machine, the wafer is held on a chuck table in a state of being attached to the surface of a dicing tape mounted on an annular frame, and the wafer is cut along the street by a cutting blade. If eyes are clogged or chipped, chipping may occur on both sides of the cutting groove formed on the wafer. In particular, the chip generated on the back side of the wafer is often larger than the chip generated on the front surface, and there is a problem that the quality of the device is remarkably deteriorated. (See Patent Document 1).

JP-A-6-112310

  As described above, in order to detect whether or not chipping has occurred on both sides of the cutting groove formed on the wafer, after the wafer is cut by the cutting blade, the cutting groove is imaged from the surface side of the wafer by the alignment means. To confirm. However, when the image is taken by the alignment means, the surface side of the cutting groove formed on the wafer can be clearly imaged, but a chip on the back side cannot be detected.

  In order to check the back side of the cutting groove formed on the wafer, the cutting groove formed on the wafer may be imaged from the back side, but a dicing tape is attached to the back side of the wafer, and the dicing is performed. Since the tape is subjected to rough processing such as frosted glass in order to facilitate separation from the chuck table, there is a problem that it is difficult to image the cutting grooves formed on the wafer via the dicing tape. is there.

  The present invention has been made in view of the above-mentioned facts, and a main technical problem thereof is a cutting groove detection device and a cutting groove detection capable of detecting a cutting groove formed on a wafer from the back side through a dicing tape. The object is to provide a cutting machine equipped with the apparatus.

In order to solve the above-mentioned main technical problem, according to the present invention, a cutting groove formed by a cutting blade on a wafer attached to the surface of a dicing tape attached to an annular frame is detected via the dicing tape. In the cutting groove detecting device to
Water that forms a water layer between an imaging camera, an objective lens holding cylinder that holds an objective lens disposed on the optical axis of the imaging camera, and an object attached to the upper end of the objective lens holding cylinder An imaging means comprising a layer forming means;
Display means for displaying an image captured by the imaging camera of the imaging means,
A cutting groove detecting device is provided.

  It is desirable that a light emitting means for irradiating light toward the objective lens is provided between the imaging camera and the objective lens.

Further, according to the present invention, a cassette that accommodates a wafer attached to the surface of a dicing tape attached to an annular frame, temporary placement means for temporarily placing the wafer carried out of the cassette, and the temporary A chuck table for holding the wafer conveyed from the placing means, a cutting means having a cutting blade for cutting the wafer held on the chuck table, and a cleaning means for cleaning the wafer cut by the cutting means And a cutting machine that carries the wafer returned from the cleaning means back to the temporary placement means into the cassette,
Water that forms a water layer between an imaging camera, an objective lens holding cylinder that holds an objective lens disposed on the optical axis of the imaging camera, and an object attached to the upper end of the objective lens holding cylinder The imaging means of the cutting groove detecting device comprising an imaging means comprising a layer forming means and a display means for displaying an image taken by the imaging camera of the imaging means is disposed in the movement path of the wafer. ing,
The cutting machine characterized by this is provided.

  A cutting groove detection device according to the present invention includes an imaging camera, an objective lens holding cylinder that holds an objective lens disposed on the optical axis of the imaging camera, and an object mounted on the upper end of the objective lens holding cylinder. A cutting groove formed on the wafer, comprising: an imaging means having a water layer forming means for forming a water layer; and a display means for displaying an image taken by the imaging camera of the imaging means. When an image is taken by the imaging camera from the dicing tape side to which the wafer is attached, a water layer can be formed between the wafer and the dicing tape. Therefore, since water can be permeated into the dicing tape, even if the back surface (lower surface) of the dicing tape is roughed, the cutting groove formed on the wafer through the dicing tape by the action of the permeated water. Can be clearly picked up, and the state of the back side of the cutting groove formed on the wafer can be confirmed by displaying the picked up image on the display means.

  Further, in the cutting machine according to the present invention, since the image pickup means of the cutting groove detection device is disposed in the wafer movement path, the cut wafer is immediately imaged and the state of the back side of the cutting groove is confirmed. Therefore, when there is a chip in the cutting groove, it is possible to smoothly implement the replacement of the cutting blade, dressing, and the like.

The perspective view of the cutting machine comprised by this invention. The front view which fractures | ruptures and shows the principal part in 1st Embodiment of the cutting groove detection apparatus comprised by this invention. Explanatory drawing which shows the state which images the cutting groove formed in the wafer using the cutting groove detection apparatus shown in FIG. The principal part sectional drawing in 2nd Embodiment of the cutting groove detection apparatus comprised by this invention.

  Hereinafter, a preferred embodiment of a cutting device constituted by the present invention will be described in more detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a cutting machine equipped with a cutting groove detecting device constructed according to the present invention. The cutting machine shown in FIG. 1 includes a device housing 2 having a substantially rectangular parallelepiped shape. In the apparatus housing 2, a chuck table 3 for holding a workpiece is disposed so as to be movable in a cutting feed direction (X-axis direction) indicated by an arrow X. The chuck table 3 includes a chuck table main body 31 and a suction chuck 32 disposed on the upper surface of the chuck table main body 31, and a wafer which is a workpiece on a holding surface which is the upper surface of the suction chuck 32. Is sucked and held by operating a suction means (not shown). The chuck table 3 is configured to be rotatable by a rotation mechanism (not shown). The chuck table body 31 is provided with a clamp 33 for fixing an annular frame that supports a wafer, which will be described later, via a dicing tape. A cover table 35 is provided by inserting the chuck table 3 configured as described above. The cover table 35 is configured to be movable together with the chuck table 3 in a cutting feed direction (X-axis direction) indicated by an arrow X. ing. The chuck table 3 and the cover table 35 can be moved in the X-axis direction by a cutting feed means (not shown).

  The cutting machine in the illustrated embodiment includes a spindle unit 4 as cutting means. The spindle unit 4 is mounted on a moving base (not shown) and is adjusted to move in a direction indicated by an arrow Y that is an indexing direction and a direction indicated by an arrow Z that is a cutting direction. A rotary spindle 42 supported and rotated by a rotary drive mechanism (not shown) is provided, and a cutting blade 43 attached to the rotary spindle 42 is provided. Cutting water supply nozzles 44 are disposed on both sides of the cutting blade 43. This cutting water supply nozzle 44 is connected to a cutting water supply means (not shown).

  The cutting machine in the illustrated embodiment captures an image of the surface of the wafer, which is a workpiece, held on the surface of the suction chuck 32 constituting the chuck table 3, and detects an area to be cut by the cutting blade 43. Or an alignment means 5 for confirming the state of the cutting groove. The alignment means 5 is composed of optical means such as a microscope and a CCD camera. The cutting machine in the illustrated embodiment includes a display unit 6 that displays an image captured by the alignment unit 5.

  The cutting machine in the illustrated embodiment includes a cassette 10 that accommodates a wafer as a workpiece. The cassette 10 is provided with a workpiece loading / unloading opening 101 for loading / unloading a wafer as a workpiece, and a plurality of rack shelves 102 for loading the wafer are vertically arranged on the inner surfaces of both side walls. It is provided facing. A wafer 11 which is a workpiece to be stored in the cassette 10 is formed in a disk shape as shown in FIG. 1, and ICs are formed in a large number of areas partitioned by streets 111 formed in a lattice shape on the surface thereof. A device 112 such as an LSI is formed. The wafer 11 formed in this way is stuck on the surface of a dicing tape 13 mounted on an annular frame 12 having a circular opening 12a. The dicing tape 13 is made of a synthetic resin sheet such as polyolefin, and the back surface (lower surface) is roughened to make it easy to separate from the chuck table 3 and is translucent. The cassette 10 containing the wafer 11 adhered to the surface of the dicing tape 13 mounted on the annular frame 12 in this way has the workpiece loading / unloading opening 101 facing the temporary placement means 14 and the cassette mounting mechanism 7. The cassette mounting table is mounted on 71. The cassette mounting table 71 can be lifted and lowered by lifting means (not shown).

  The cutting machine in the illustrated embodiment includes a carry-in / out means 15 for carrying out the wafer 11 as a workpiece housed in the cassette 10 to the temporary placing means 14 and carrying the wafer 11 after the cutting into the cassette 10; First transport means 16 for transporting the wafer 11 carried out by the carry-in / out means 15 onto the chuck table 3, cleaning means 17 for cleaning the wafer 11 cut on the chuck table 3, and the chuck table 3. There is provided a second cleaning / conveying means 18 for conveying the wafer 11 cut above to the cleaning means 17.

The cutting operation by the cutting machine configured as described above will be briefly described.
A wafer 11 (hereinafter referred to as a single wafer 11) attached to the surface of a dicing tape 13 attached to an annular frame 12 accommodated in a predetermined position of a cassette 10 placed on a cassette placement table 71 is as follows. The cassette mounting table 71 is moved up and down by an elevating means (not shown) to be positioned at the unloading position. Next, the carry-in / out means 15 moves forward and backward to carry the wafer 11 positioned at the carry-out position onto the temporary placement means 14. The wafer 11 carried out to the temporary placing means 14 is conveyed onto the chuck table 3 by the turning operation of the first conveying means 16. When the wafer 11 is placed on the chuck table 3, suction means (not shown) is operated to suck and hold the wafer 11 on the chuck table 3. The annular frame 12 that supports the wafer 11 via the dicing tape 13 is fixed by the clamp 33.

  The chuck table 3 holding the wafer 11 in this way is moved to a position immediately below the alignment means 5. When the chuck table 3 is positioned immediately below the image pickup means 5, an alignment process for detecting a processing region to be cut on the wafer 11 by the alignment means 5 and a control means (not shown) is executed. That is, the alignment unit 5 and a control unit (not shown) perform image processing such as pattern matching for aligning the street 111 formed in a predetermined direction of the wafer 11 with the cutting blade 43 that cuts along the street 111. To perform the alignment of the machining area to be cut. In addition, alignment of the machining area to be cut is similarly performed on the street 111 formed on the wafer 11 and extending in a direction orthogonal to the predetermined direction.

  Thereafter, the chuck table 3 is moved to a cutting region below the cutting blade 43, the cutting blade 43 is rotated in a predetermined direction, and a predetermined amount is cut and fed in the direction indicated by the arrow Z. Position at a position reaching the dicing tape 13. Then, the chuck table 3 holding the wafer 11 by suction is moved at a predetermined cutting feed speed in the direction indicated by the arrow X which is the cutting feed direction. As a result, the wafer 11 held on the chuck table 3 is cut along the predetermined street 111 by the cutting blade 43 (cutting process). When performing this cutting process, cutting water is sprayed from the cutting water supply nozzle 44 toward the side surface of the cutting blade 43.

  When the wafer 11 is cut along a predetermined street as described above, the chuck table 3 is indexed and fed in the direction indicated by the arrow Y in FIG. If the cutting process is performed along all the streets extending in the predetermined direction of the wafer 11, the chuck table 3 is rotated 90 degrees so that the street extends in a direction perpendicular to the predetermined direction of the wafer 11. By performing the cutting process along, all the streets 111 formed in a lattice shape on the wafer 11 are cut and divided into individual devices. Each divided device does not fall apart due to the action of the dicing tape 13, and the state of the wafer supported by the annular frame 12 is maintained.

  As described above, when the cutting process is completed along the street of the wafer 11, the chuck table 3 holding the wafer 11 is first returned to the position where the wafer 11 is sucked and held. Then, the suction holding of the wafer 11 is released. Next, the wafer 11 is transported to the cleaning means 17 by the second transport means 18. The wafer 11 conveyed to the cleaning means 17 is cleaned here. The wafer 11 thus cleaned is transported to the temporary placement means 14 by the first transport means 16 after drying. Then, the wafer 11 is stored in a predetermined position of the cassette 10 by the loading / unloading means 15.

  In the above-described cutting process, when the cutting blade 43 is clogged or chipped, chipping may occur on both sides of the cutting groove formed in the wafer 11. Therefore, in order to detect the state of the cutting groove formed on the wafer 11, the wafer 11 on which the cutting groove is formed is positioned immediately below the alignment means 5, and the cutting groove formed on the wafer 11 is imaged by the alignment means 5. Check the condition of the cutting groove. However, if an image is taken by the alignment means 5, the surface side of the cutting groove formed in the wafer 11 can be clearly imaged, but the state on the back side cannot be confirmed. Therefore, it is desirable that a cutting groove detection device capable of confirming the state of the back side of the cutting groove formed on the wafer 11 is disposed on the moving path of the wafer on which the cutting groove is formed. Hereinafter, a first embodiment of a cutting groove detection device capable of confirming the state of the back surface of the cutting groove formed on the wafer 11 will be described with reference to FIGS. 2 and 3.

  FIG. 2 is a front view of the cutting groove detecting device 20 configured according to the present invention, with a main portion thereof broken away. The cutting groove detection device 20 shown in FIG. 2 includes an imaging unit 21 and a display unit 29 that displays an image captured by the imaging unit 21. The imaging means 21 includes an imaging camera 22, an objective lens holding cylinder 24 that is disposed on the optical axis of the imaging camera 22 and holds the objective lens 23, and the objective lens 23 between the imaging camera 22 and the objective lens 23. The light emitting means 25 which irradiates light toward is comprised. The light emitting means 25 is disposed on the optical axis of the imaging camera 22 in the objective lens holding cylinder 24 and the light source 251 connected to the hole 241 formed between the imaging camera 22 and the objective lens 23 in the objective lens holding cylinder 24. And a half mirror 252 that changes the direction of light from the light source 251 toward the objective lens 23.

  The imaging means 21 constituting the cutting groove detecting device 20 shown in FIG. 2 includes a water layer forming means 26 that is attached to the upper end portion of the objective lens holding cylinder 24 and forms a water layer with the subject. The water layer forming means 26 includes an annular member 261 having a hole 261a at the center. A fitting recess 261 b having an inner diameter corresponding to the outer diameter of the objective lens holding cylinder 24 is formed at the lower end of the annular member 261, and the fitting recess 261 b is fitted into the upper end of the objective lens holding cylinder 24. It is done. In this way, the upper surface of the annular member 261 attached to the upper end portion of the objective lens holding cylinder 24 is formed in a plane perpendicular to the optical axis of the imaging camera 21. A fitting recess 261c having an inner diameter larger than the hole 261a is formed at the upper end of the annular member 261, and a transparent plate 262 such as glass is fitted into the fitting recess 261c. The annular member 261 formed in this way is formed with a plurality of water supply holes 261d that open above the transparent plate 262 on the inner peripheral surface of the fitting recess 261c, and the plurality of water supply holes 261d. A water supply passage 261e communicating with the water supply passage 261e is formed. The water supply passage 261 e of the annular member 261 configured in this way is connected to the water supply means 27.

  The imaging unit 21 constituting the cutting groove detection device 20 configured as described above sends an image signal captured by the imaging camera 22 through the half mirror 252 and the objective lens 22 to the control unit 28. Then, the control unit 28 displays an image based on the image signal input from the imaging camera 22 on the display unit 29. The display means 29 can be the display means 6 when the cutting groove detection device 20 is provided in a cutting machine.

  The cutting groove detection device 20 shown in FIG. 2 is configured as described above, and the imaging means 21 is disposed on the wafer movement path in which the cutting grooves in the cutting device shown in FIG. 1 are formed. The position where the image pickup means 21 of the cutting groove detecting device 20 is disposed is cleaned by the transfer path A of the second cleaning transfer means 18 for transferring the wafer subjected to the cutting process to the cleaning means 17 and the cleaning means 17. The transfer path B of the first transfer means 16 for transferring the transferred wafer to the temporary placement means 14, and the loading / unloading means 15 for loading the wafer transferred to the temporary placement means 14 into the cassette 10 placed on the cassette placement table 71. An area D of the cover table 35 that forms a moving path of the wafer moving in the cutting feed direction (X-axis direction) together with the conveyance path C and the chuck table 3 holding the wafer is appropriate.

Next, the case where the imaging means 21 of the cutting groove detection device 20 is disposed in the transport path A will be described with reference to FIG.
As described above, the chuck table 3 holding the wafer 11 subjected to the cutting process is first returned to the position where the wafer 11 is sucked and held (the position shown in FIG. 1), and the wafer 11 held on the chuck table 3 is returned. However, a cutting groove detection step by the cutting groove detection device 20 is performed in the middle of being transferred to the cleaning means 17 by the second transfer means 18. That is, as shown in FIG. 3, the second conveying means 18 holds the annular frame 12 on which the dicing tape 13 to which the wafer 11 is attached is held, and detects the cutting groove disposed in the conveying path A. A predetermined gap (for example, between the upper surface of the annular member 261 constituting the water layer forming means 25 and the dicing tape 13 to which the wafer 11 as the subject is attached is conveyed above the imaging means 21 constituting the apparatus 20. Provide 1-2mm). Next, when water is supplied by operating the water supply means 27 of the cutting groove detection device 20, this water is supplied to the water supply passage 261 e of the annular member 261 constituting the water layer forming means 26 of the imaging means 21, and a plurality of water supplies. A water layer 200 is formed between the upper surface of the annular member 261 and the dicing tape 13 to which the wafer 11 as the subject is attached through the hole 261d and the fitting recess 261c. . Therefore, even if water penetrates into the dicing tape 13 and rough processing is applied to the back surface (lower surface) of the dicing tape 13, the cutting groove formed in the wafer 11 through the dicing tape 13 by the action of the penetrated water. Can be imaged.

  Thus, the imaging means 21 is in a state where the water layer 200 is formed between the upper surface of the annular member 261 constituting the water layer forming means 26 of the imaging means 21 and the dicing tape 13 to which the wafer 11 is adhered. The light source 251 of the light emitting means 25 is turned on, and light is irradiated to the back surface (lower surface) of the dicing tape 13 through the half mirror 252 and the objective lens 23. Then, the image pickup means 21 operates the image pickup camera 22 to pick up an image of the cutting groove formed in the wafer 11 through the dicing tape 13 and sends the image signal to the control means 28. The control unit 28 displays an image based on the image signal input from the imaging camera 22 on the display unit 29. In the image displayed on the display means 29, the cutting grooves 110 formed on the wafer 11 are displayed darkly, and the chips 110 a generated on the back surface (lower surface) side on both sides of the cutting grooves 110 are also displayed darkly. Thus, based on the image displayed on the display means 29, the state of the back surface side of the cutting groove 110 formed in the wafer 11 can be confirmed. And if it detects that the chip | tip 110a has generate | occur | produced on both sides of the cutting groove 110, measures, such as replacement | exchange of the cutting blade 43 and dressing, will be taken.

Next, a second embodiment of the cutting groove detection device will be described with reference to FIG.
FIG. 4 shows a cross-sectional view of the water layer forming means 26 constituting the imaging means 21 of the cutting groove detecting device 20. In addition, the code | symbol of each part in the water layer formation means 26 shown in FIG. 4 is demonstrated using the same code | symbol as the water layer formation means 26 which comprises the imaging means 21 of the cutting groove detection apparatus 20 shown in the said FIG. 2 and FIG. . In the water layer forming means 26 constituting the imaging means 21 of the cutting groove detecting device 20 shown in FIG. 4, the fitting recess 261c provided at the upper end of the annular member 261 constituting the water layer forming means 26 is formed shallow, The upper surface of the transparent plate 262 fitted in the fitting recess 261c is formed to be flush with the upper surface of the annular member 261. A plurality of water supply holes 261 d formed in the annular member 261 are provided to open on the upper surface of the annular member 261. Other configurations are substantially the same as the configuration of the annular member 261 that constitutes the water layer forming means 26 of the imaging means 21 shown in FIGS. 2 and 3, and the same parts and members are the same. The reference numerals are attached and the description is omitted. Also in the annular member 261 constituting the water layer forming means 26 of the imaging means 21 configured as described above, by supplying water from the water supply passage 261e to the plurality of water supply holes 261d, the upper surface of the annular member 261 and the subject A water layer can be formed between the wafer 11 and the dicing tape 13 to which the wafer 11 is attached, and the same effect as the cutting groove detection device 20 shown in FIGS. 2 and 3 can be obtained.

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, in the above-described embodiment, the example in which the imaging unit 21 of the cutting groove detection device 20 is disposed in the cutting machine has been described. However, the cutting groove detection device 20 can be used as a single device.

2: device housing 3: chuck table 4: spindle unit 42: rotating spindle 43: cutting blade 5: alignment means 7: cassette mounting mechanism 10: cassette 11: wafer 12: annular frame 13: dicing tape 14: temporary placing means 15: carry-in / out means 16: first transport means 17: cleaning means 18: second cleaning transport means 20: cutting groove detection device 21: imaging means 22: imaging camera 23: objective lens 24: objective lens holding cylinder 25: Light emitting means 26: Aqueous layer forming means 27: Water supply means 28: Control means 29: Display means

Claims (3)

In a cutting groove detection device for detecting a cutting groove formed by a cutting blade on a wafer attached to the surface of a dicing tape attached to an annular frame via the dicing tape,
Water that forms a water layer between an imaging camera, an objective lens holding cylinder that holds an objective lens disposed on the optical axis of the imaging camera, and an object attached to the upper end of the objective lens holding cylinder An imaging means comprising a layer forming means;
Display means for displaying an image captured by the imaging camera of the imaging means,
A cutting groove detecting device characterized by that.   The cutting groove detection device according to claim 1, further comprising a light emitting unit that irradiates light toward the objective lens between the imaging camera and the objective lens. A cassette for storing a wafer attached to the surface of a dicing tape mounted on an annular frame, a temporary placement means for temporarily placing the wafer carried out of the cassette, and the wafer conveyed from the temporary placement means A chuck table, a cutting means having a cutting blade for cutting the wafer held on the chuck table, and a cleaning means for cleaning the wafer cut by the cutting means. In the cutting machine adapted to carry the wafer returned from the temporary storage means to the cassette,
Water that forms a water layer between an imaging camera, an objective lens holding cylinder that holds an objective lens disposed on the optical axis of the imaging camera, and an object attached to the upper end of the objective lens holding cylinder The imaging means of the cutting groove detecting device comprising an imaging means comprising a layer forming means and a display means for displaying an image taken by the imaging camera of the imaging means is disposed in the movement path of the wafer. ing,
A cutting machine characterized by that.

Images