JP2009064828A - Processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clearly recognize the area of a fault when finding the fault in an image displayed on a monitor and to speedily and suitably clear up the causes and so on. <P>SOLUTION: A processing device includes a chuck table which holds a workpiece, a processing means of processing the workpiece held by the chuck table, an imaging means of imaging the workpiece, and a display means of displaying an image imaged by the imaging means, wherein the imaging means has a whole imaging unit which images the whole workpiece held by the chuck table, a detail imaging unit which images details of the workpiece, and an image composing unit which puts together and displays the whole image of the workpiece imaged by the whole imaging unit and the detailed image obtained by the detail imaging unit on the display means and also displays the position of the detailed image in the whole image of the workpiece. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a processing apparatus including a display unit that can visually confirm an alignment region or a processing region.

  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 division line is cut by a dicing machine (cutting machine) and divided into individual devices, which are used for electric devices such as mobile phones and personal computers.

  The dicing apparatus includes a chuck table that holds a semiconductor wafer, a cutting unit that cuts the wafer held on the chuck table, an imaging unit that images the wafer, and a display unit that displays an image captured by the imaging unit. In addition, the wafer can be imaged by the imaging means to detect a region to be cut, and the wafer can be divided into individual devices (semiconductor chips) with high accuracy.

  Since dicing (cutting) of the wafer is performed along the street, an operation called alignment for detecting the street in advance is performed prior to dicing. This alignment is performed by imaging the surface of the semiconductor wafer with an imaging unit, and pattern matching between an alignment key pattern formed on the surface and a key pattern previously stored in the alignment apparatus.

  Japanese Patent Application Laid-Open No. 2005-166991 discloses an alignment apparatus capable of simultaneously displaying a low-magnification image and a high-magnification image on a display unit, improving the operator's work efficiency, and reducing the time required for alignment. is doing.

In Japanese Patent No. 2628256, a kerf (cutting groove) formed on a semiconductor wafer is picked up by an image pickup means, the picked-up image is processed to automatically detect a state such as chipping, and the like. An automatic dicing system based on kerf check is disclosed in which pre-cut is performed when the value exceeds a predetermined value, and dicing is performed when the value does not exceed the predetermined value.
Japanese Patent Laid-Open No. 2005-166991 Japanese Patent No. 2628256

  According to the alignment apparatus disclosed in Patent Document 1, there is an effect that the time required for alignment can be shortened. However, when alignment is performed in an appropriate region or an alignment error occurs, the region is visually checked. There is a problem that cannot be confirmed.

  In the automatic dicing system disclosed in Patent Document 2, the operator roughly recognizes the area imaged by the imaging means, but if an inappropriate cutting groove is detected, that area is a part of the wafer. There is a problem that it is not possible to clearly recognize whether or not this is true, and the cause cannot be investigated quickly.

  The present invention has been made in view of such points, and the object of the present invention is to clearly recognize the area when a defect is found in the detailed image displayed on the monitor, The object is to provide a processing apparatus capable of quickly and properly investigating the cause.

  According to the present invention, a chuck table that holds a workpiece, a processing unit that processes the workpiece held on the chuck table, an imaging unit that images the workpiece, and an image captured by the imaging unit. A processing apparatus including a display unit for displaying, wherein the imaging unit includes an entire imaging unit that images the entire workpiece held on the chuck table, and a detailed imaging unit that images the details of the workpiece. And the overall image of the workpiece imaged by the overall imaging unit and the detail image captured by the detail imaging unit are combined and displayed on the display means, and the position of the detail image is displayed on the entire image of the workpiece. An image synthesizing unit for displaying is provided.

  According to the present invention, the image pickup means includes an image composition unit for combining the whole image of the workpiece and the detailed image on the display means and displaying the position of the detailed image on the whole image of the workpiece. Therefore, when a defect is found in the detailed image, the area can be clearly recognized, and the cause can be investigated quickly and appropriately.

  In addition, it is possible to recognize whether the alignment is performed in an appropriate region, and it is possible to recognize the region when an alignment error occurs.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the external appearance of a cutting device (dicing device) 2 that can divide a wafer into individual chips (devices).

  On the front side of the cutting device 2, there is provided operating means 4 for an operator to input instructions to the device such as machining conditions. In the upper part of the apparatus, there is provided a display means (monitor) 6 such as a CRT for displaying a guidance screen for an operator and an image taken by an imaging means described later.

  As shown in FIG. 2, on the surface of the wafer W to be diced, the first street S1 and the second street S2 are formed orthogonally, and the first street S1 and the second street S2 A plurality of devices D are partitioned and formed on the wafer W.

  The wafer W is attached to a dicing tape T that is an adhesive tape, and the outer peripheral edge of the dicing tape T is attached to an annular frame F. As a result, the wafer W is supported by the frame F via the dicing tape T, and a plurality of wafers (for example, 25 sheets) are accommodated in the wafer cassette 8 shown in FIG. The wafer cassette 8 is placed on a cassette elevator 9 that can move up and down.

  Behind the wafer cassette 8, a loading / unloading means 10 for unloading the wafer W before cutting from the wafer cassette 8 and loading the wafer after cutting into the wafer cassette 8 is disposed. Between the wafer cassette 8 and the loading / unloading means 10, a temporary placement area 12, which is an area on which a wafer to be carried in / out, is temporarily placed, is provided. Positioning means 14 for positioning at a certain position is provided.

  In the vicinity of the temporary placement area 12, transport means 16 having a turning arm that sucks and transports the frame F integrated with the wafer W is disposed, and the wafer W carried to the temporary placement area 12 is It is attracted by the transport means 16 and transported onto the chuck table 18 and is sucked by the chuck table 18, and is held on the chuck table 18 by fixing the frame F by a plurality of fixing means 19.

  The chuck table 18 is configured to be rotatable and reciprocally movable in the X-axis direction. Above the movement path of the chuck table 18 in the X-axis direction, an alignment unit 20 that detects a street to be cut of the wafer W is provided. It is arranged.

  The alignment means 20 has a condensing optical system 22, and a part of the reflected light from the wafer W collected by the condensing optical system 22 is input to a detail imaging unit described later, and the surface of the wafer W is imaged. Is done.

  Based on the image acquired by imaging, a street to be cut is detected by a pattern matching process described in detail later. The image acquired by the detail imaging unit is displayed on the display means 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 an extension line of the condensing optical system 22 in the X-axis direction.

  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 transport unit 16, and the wafer W integrated with the frame F is transported to the chuck table 18 and held by the chuck table 18 as the transport unit 16 rotates. 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 35 captures the surface of the wafer W and causes the display unit 6 to display the captured image.

  As shown in FIG. 3, the imaging means 35 includes a high-magnification detail imaging unit 32 having a CCD and a low-magnification whole imaging unit 34 having the same CCD, and the light transmitted through the half mirror 30 is captured in detail. The optical axes of the condensing optical system 22, the detail imaging unit 32, and the entire imaging unit 34 are adjusted so that the light input to the unit 32 and reflected by the half mirror 30 is input to the entire imaging unit 34. .

  The entire image of the wafer W imaged by the overall imaging unit 34 and the detailed image captured by the detail imaging unit 32 are synthesized by the image synthesis unit 36, and the detail image 38a is displayed on the left side by dividing the screen of the display means 6 into two. The entire image 38b is displayed on the right side. That is, the image composition unit 36 performs display processing of an image to be displayed on the display unit 6. The image composition unit 36 further performs processing for displaying the position P of the detail image 38a on the entire wafer image 38b.

  Hereinafter, the outline of the alignment of the embodiment of the present invention by the imaging means 35 will be described. When the wafer W is positioned immediately below the condensing optical system 22, the detailed imaging unit 32 captures the wafer W at a high magnification and the overall imaging unit 34 at a low magnification, and an image synthesized by the image synthesis unit 36 is displayed on the display unit 6. Is divided into two and displayed as a detail image 38a and an entire image 38b.

  The operator of the cutting apparatus 2 operates the operation means 4 to search for a key pattern 40 that is a pattern matching target while slowly moving the detail image 38a. The key pattern 40 uses, for example, a characteristic part of a circuit in the device D.

  When the operator determines the key pattern 40, an image including the key pattern 40 is stored in a memory provided in the alignment unit 20 of the cutting apparatus 2. Further, the distance between the key pattern 40 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 slowly moving the detailed image 38a on the screen, the distance 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 alignment means 20. deep.

  At the time of cutting along the street of the wafer W, the alignment unit 20 performs pattern matching between the stored image of the key pattern 40 and the image actually captured and acquired by the detail imaging unit 32. This pattern matching is performed at at least two points separated from each other along the same street S1 extending in the X-axis direction.

  First, the detailed image 38a picked up at point A is slowly moved on the screen while the stored key pattern 40 and the key pattern 40 of the actual image are subjected to pattern matching, and the screen is displayed with the key pattern matched. Fix it. At this time, the position P of the detail image 38a is displayed in the entire image 38b on the right side. Therefore, the operator can easily know the position of the detailed image 38a displayed on the left screen.

  When pattern matching is performed from the imaging screen at point A as described above, the chuck table 18 is moved in the X-axis direction, and pattern matching is performed at point B that is considerably separated from point A in the X-axis direction.

  At this time, instead of moving from point A to point B at once, pattern matching is performed, but pattern matching is performed as necessary at a plurality of points in the middle of movement to point B to correct the deviation in the Y-axis direction. It is preferable to slightly rotate the chuck table 18 to perform θ correction and finally perform pattern matching at point B.

  When the pattern matching at the points A and B is completed, the straight line connecting the two key patterns 40 is parallel to the street S1, and the cutting means is equal to the distance between the key pattern 40 and the center line of the street S1. By moving 24 in the Y-axis direction, the street to be cut and the cutting blade 28 are aligned.

  According to the imaging means 35 of the present embodiment, the detail image 38a and the whole image 38b synthesized by the image synthesis unit 36 are displayed by dividing the screen of the display means 6 into two, and the detail image is displayed on the whole image 38b of the wafer W. Since the position P of 38a is displayed, it is possible to recognize whether or not the alignment is performed in an appropriate region, and it is possible to immediately confirm the region when an alignment error occurs.

  When the street to be cut and the cutting blade 28 are aligned, the chuck table 18 is moved in the X-axis direction, and the cutting means 24 is lowered while rotating the cutting blade 28 at a high speed. The street was 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.

  The wafer W that has been cut is moved in the X-axis direction by the chuck table 18 and is then gripped by the transfer means 25 that can move in the Y-axis direction and transferred to the cleaning device 27. The cleaning device 27 cleans the wafer by rotating the wafer W at a low speed (for example, 300 rpm) while jetting water from the cleaning nozzle.

  After the cleaning, the wafer W is dried at a high speed (for example, 3000 rpm) by blowing air from the air nozzle and drying the wafer W. Then, the wafer W is adsorbed by the conveying means 16 and returned to the temporary storage area 12, and then the loading / unloading means. 10, the wafer W is returned to the original storage location of the wafer cassette 8.

  Here, when it is desired to observe the state of the cutting groove during the wafer W cutting, the cutting is stopped, the chuck table 18 is moved in the X-axis direction, and the wafer W is positioned directly below the condensing optical system 22. Then, the wafer W is imaged by the detail imaging unit 32 and the entire imaging unit 34 of the imaging unit 35, and the screen of the display unit 6 is divided into two to display the detail image 42a and the entire image 42b.

  Similarly to the alignment, the position Q of the detailed image 42a is displayed on the entire image 42b of the wafer W. Therefore, if the operator determines that the cutting groove 44 displayed in the detailed image 42a is not suitable due to a lot of chipping or the like, the area can be clearly recognized on the entire screen 42b. , Cause investigation and the like can be performed promptly and appropriately.

  In the above description, the example in which the imaging unit of the present invention is applied to a cutting apparatus has been described. However, the present invention is not limited to this, and the imaging unit of the present invention is also applied to a grinding apparatus or a laser processing apparatus. can do.

1 is an overall perspective view of a cutting apparatus to which the present invention is applied. It is a perspective view which shows the wafer integrated with the flame | frame. It is explanatory drawing explaining embodiment of this invention at the time of alignment. It is explanatory drawing explaining this invention embodiment at the time of cutting groove observation.

Explanation of symbols

6 Display means 22 Condensing optical system 24 Cutting means 26 Spindle 28 Cutting blade 30 Half mirror 32 Detail imaging section 34 Whole imaging section 35 Imaging means 36 Image composition sections 38a and 42a Detail images 38b and 42b Whole image 40 Key pattern

Claims (1)

A chuck table for holding a workpiece, a processing means for processing the workpiece held on the chuck table, an imaging means for imaging the workpiece, and a display means for displaying an image captured by the imaging means A processing apparatus comprising:
The imaging means includes
An overall imaging unit for imaging the entire workpiece held by the chuck table;
A detail imaging unit for imaging the details of the workpiece;
The entire image of the workpiece imaged by the entire imaging unit and the detail image captured by the detail imaging unit are combined and displayed on the display means, and the position of the detail image is displayed on the entire image of the workpiece. An image composition unit;
A processing apparatus comprising:

Images