JP3280736B2 - Dicing groove position measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for observing the surface of a workpiece by observing the surface of the workpiece using a projection device which is positioned in advance with respect to a cutting blade so that a desired position on the surface of the workpiece can be processed. The present invention relates to a dicing groove position measuring method for measuring a position of a groove machined by a cutting blade in order to detect a positional relationship between the cutting blade and a projection device in a dicing device that is adjusted.

[0002]

2. Description of the Related Art A dicing apparatus is an apparatus for processing a thin groove with a cutting blade rotating at a high speed, and is widely used for processing for cutting a semiconductor chip formed on a semiconductor wafer from the wafer. For this reason, a case where a groove is formed in a semiconductor wafer will be described here as an example.

FIG. 3 is a diagram showing a basic configuration of a dicing apparatus. In FIG. 3, reference numeral 1 denotes a cutting blade (blade) in which abrasive grains such as diamond are fixed with nickel or the like, and is rotated at high speed by a spindle motor 11. 2
Is a stage for fixing the semiconductor wafer 100 by vacuum suction, which is moved by a precision moving mechanism (not shown). Reference numeral 100 denotes a semiconductor wafer on which a groove is formed.
The groove processing is performed by moving the stage 2 on which 0 is placed. In all the drawings, common functional portions are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 4 denotes a projection device for measuring the position of the semiconductor wafer 100 mounted on the stage 2. It is extremely difficult to precisely match the predetermined position in the field of view of the projection device 4 with the processing position of the blade 1, and the processing value on the surface of the semiconductor wafer 100 is determined by the predetermined position in the field of view of the projection device 4 that does not correctly match. When the position is automatically determined, the groove cannot be accurately processed at a desired position on the semiconductor wafer 100. Then, the stage 2 on which the semiconductor wafer 100 is mounted is moved below the field of view of the projection device 4 so that a predetermined position on the semiconductor wafer 100 is adjusted to a predetermined position within the field of view of the projection device 4. The projection device 4 is adjusted in advance so as to have a predetermined positional relationship with the processing position of the blade 1. By performing the above-described position adjustment, the position on the surface of the semiconductor wafer 100 and the processing position of the blade 1 are adjusted. Is determined, and by moving the stage 2 by a precise moving mechanism, a groove can be accurately processed at a desired position on the semiconductor wafer 100.

As shown in FIG. 3, a projection device 4 includes a microscope lens 41 for enlarging and projecting an image on the surface of a semiconductor wafer 100, a lamp 42 for illuminating a surface to be projected, and a TV receiving the enlarged image. It has a camera 43 and performs positioning while viewing the image on the monitor. In some cases, the position is adjusted by directly looking at the microscope without using the TV camera 43, and the video signal of the TV camera 43 is image-processed,
In some cases, alignment may be performed automatically.

The semiconductor wafer 100 is fixed to the stage 2. In order to prevent the semiconductor wafer 100 from falling apart during processing, an adhesive tape is stuck to the back surface of the semiconductor wafer 100 and then fixed to the stage 2. It is. If the workpiece is other than a semiconductor wafer, it may be fixed using an adhesive. When the adhesive tape is attached to the back surface of the semiconductor wafer 100, as shown in FIG. 4, the adhesive tape 102 is attached to a frame 101 having a hole in the center, and the semiconductor wafer 100 is attached to the center hole. Is mounted on the stage 2 and fixed. Fig. 4 also shows transport between processes
This is performed in the state shown in FIG.

[0007] A large number of chips are formed on the semiconductor wafer 100, and a groove is formed between the chips by a dicing apparatus to separate the chips. FIG. 5 is a view showing an arrangement state of the chips 110 on the semiconductor wafer 100. Semiconductor wafer 10
The diameter of 0 is about 150 mm to 200 mm, and each chip is about 10 mm square. The width d of the part called the street 120 between the chips is 100
In this portion, a groove having a width of about 20 μm needs to be formed over both ends of the semiconductor wafer 100.

As described above, since a groove having a length of about 200 mm at the maximum is formed in a portion having a width of about 100 μm, it is required that the positioning of the semiconductor wafer 100 with respect to the processing position of the blade 1 be performed with high precision. In order to perform this alignment with high accuracy, it is necessary that the field of view of the projection device 4 and the processing position of the blade 1 correspond precisely in the first place. The positions of the blades of the blades 1 differ to some extent from blade to blade due to manufacturing errors and mounting errors of the blades 1 themselves. Therefore, the operation of associating the field of view of the projection device 4 with the processing position of the blade 1 is performed by measuring the position of the groove processed by the blade 1 with the projection device 4.

FIG. 6 is a diagram showing the positional relationship between the field of view of the projection device 4 and the processing position of the cutting blade 1. In the figure, 400
Indicates the center of the field of view of the projection device 4, and the center of the groove processed by the blade 1 is aligned with the center of the field of view 400
The difference between the center of the groove and the center of the field of view indicated by dy in the figure is stored, and the blade 1 is moved in consideration of the difference. In this way, the positional relationship between the field of view of the projection device 4 and the processing position of the cutting blade 1 is precisely adjusted at the time of manufacturing the device, but as shown in FIG. It has a structure supported by an arm-shaped member or a spindle motor 11 extending from a provided table. This is to secure a range in which the semiconductor wafer 100 and the like move. Therefore, it is easily affected by expansion and contraction due to temperature change, and the positional relationship between the visual field of the projection device 4 and the processing position of the blade 1 depends on the temperature due to the difference in the thermal expansion coefficient between the projection device 4 and the portion supporting the blade 1. There is a problem that changes. As described above, since the alignment by the projection device needs to be performed very precisely, a change in the positional relationship between the field of view of the projection device 4 and the processing position of the blade 1 due to a temperature change cannot be ignored, and the processing during the processing is not possible. The position of the groove is moved below the projection device 4 to measure the groove position, and the positional relationship is corrected as needed. The groove to be measured may be formed in any part as long as it can be moved together with the stage 2 and the stage 2 mounted on the stage 2, but the groove position is frequently measured. So stage 2
It is not preferable to form a groove in the groove. Therefore, a groove has been processed on the surface of the semiconductor wafer 100 and the groove position has been measured. The groove processing on the semiconductor wafer 100 is performed by a normal processing. If the groove processed part is moved under the projection device 4 and the groove position is measured during the processing, the groove position is measured. It is no longer necessary to machine grooves.

[0010]

In recent years, dicing apparatuses have been required to be automated in order to improve productivity, and automation of the measurement of the groove position is also required. In particular, since the measurement of the groove position needs to be performed at any time even during processing, the necessity of automation is great. As shown in FIG. 3, automation of the measurement of the groove position is performed by providing a TV camera 43 in the projection device 4 and performing image processing on the video output thereof.

In order to recognize the groove position by image processing, it is important that a good image is constantly projected on the TV camera 43 in a stable manner, and particularly the brightness of the image is important. For this reason, various measures have been taken such as making the lamp 42 illuminating the surface of the semiconductor wafer 100 emit a certain amount of light. However, the state of the image projected on the TV camera 43 is
Because it is also affected by the reflectivity of the semiconductor wafer surface,
When grooving different workpieces, there is a problem that good measurement of the groove position cannot be performed and accuracy of the groove position to be processed is reduced. For example, when processing a compound semiconductor wafer such as GaAs, the reflectivity is lower than that of a normal silicon wafer, so that the image projected on the TV camera 43 becomes dark, and the groove position cannot be measured as it is. Has occurred. Such a problem also occurs when the workpiece is a glass substrate. This problem is particularly serious when the groove position is automatically measured, but has a large error because the groove position is hard to see even when the groove position is measured visually.

In order to reduce such a problem, it is conceivable to change the illumination intensity according to the type of the workpiece. However, it is necessary to provide a device for changing the illumination intensity. Since it is necessary to change the intensity of the illumination according to the type of the object, there is a problem that the operation is complicated. The present invention has been made in view of the above problems, and measures the position of a groove formed in a workpiece by a projection device for positioning, thereby obtaining a positional relationship between the position of the groove to be processed and the projection device. It is an object of the present invention to make it possible to perform a good measurement irrespective of the type of a workpiece in a dicing apparatus that corrects the above.

[0013]

In order to achieve the above object, a method for measuring the position of a dicing groove according to the present invention comprises forming a groove on an adhesive tape to which a workpiece is to be attached, and positioning the groove on the adhesive tape. Is measured. That is, the method for measuring the position of the dicing groove of the present invention, a cutting blade rotating at high speed,
Comprising a stage on which the semiconductor wafer stuck on the adhesive tape is placed, a moving mechanism for moving the stage, a projection means for projecting an image of the surface of the semiconductor wafer which grooves are formed by cutting blades, semiconductor In a dicing apparatus that performs groove processing after confirming the position on the surface of the wafer based on the image projected by the projection unit, the correspondence between the position of the groove processed by the cutting blade and the position of the image projected by the projection unit A dicing groove position measuring method for measuring the relationship,
The adhesive tape has an outside diameter that exceeds the outside diameter of the semiconductor wafer.
And attached to the back side of the semiconductor wafer.
When dicing the surface of
Dice to an adhesive tape and exceed the outside diameter of the semiconductor wafer.
Position the dicing groove from the surface with the adhesive tape
It is characterized by measuring .

[0014]

In the method for measuring the position of a dicing groove according to the present invention, the measurement of the correspondence between the groove position and the image position is performed on the groove formed on the same adhesive tape. Unaffected, stable measurements can always be made. The adhesive tape is soft and seems to be unsuitable for measuring the groove position.However, when the groove was actually processed on the adhesive tape and the measurement was performed, the groove was processed on the semiconductor wafer that was the workpiece. There was no particular problem compared to.

[0015]

FIG. 1 is a diagram showing the configuration of a dicing apparatus to which the measuring method of the present invention is applied. In FIG. 1, reference numeral 1 denotes a cutting blade (blade), and 11 denotes a spindle motor that rotates the blade 1 at a high speed and is movable in the y direction in the figure. Reference numeral 2 denotes a stage for holding the semiconductor wafer 100 on which the groove processing is performed.
Moved in the direction. The control unit 5 controls the movement of the spindle 11 in the y direction and the movement of the stage 2 in the x direction. The semiconductor wafer 100 is placed on the stage 2 and processed while being attached to the adhesive tape 102 attached to the frame 101 shown in FIG. Reference numeral 4 denotes a projection device, which includes a microscope lens 41 and an illumination lamp 42.
And a TV camera 43. Microscope lens 41
Is the semiconductor wafer 100 and the frame 10
1 and the image of the surface of the adhesive tape 102 are enlarged and projected on the TV camera 43, and the TV camera 43 outputs a video signal. An image processing unit 44 processes the video signal to determine the position of the groove and measures the position, and calculates and outputs a difference dy between the center position of the image and the center position of the groove. The control unit 5 controls the movement of the blade 1 in consideration of the dy.

FIG. 2 is a view showing a state in which the stage 2 is moved below the projection device 4 in order to measure the relationship between the center position of the image of the projection device 4 and the center position of the groove.
Are moved so that the groove formed on the adhesive tape 102 comes to the center of the image of FIG. When a groove is formed in a semiconductor wafer, there are a processing method called full cut, which completely separates each semiconductor chip from the wafer in relation to a post-process, and a processing method called half cut, which leaves a part of the semiconductor chip. In the case of full-cut processing, grooves are formed in the adhesive tape 102 by normal processing. After processing an appropriate number of grooves, the stage is moved to a state as shown in FIG. Do. In the case of half-cut processing, grooves are not formed in the adhesive tape 102 by ordinary processing. Therefore, after processing an appropriate number of grooves, grooves are processed in the adhesive tape 102, and the stage is moved to a state as shown in FIG. Move to measure the groove position.

[0017]

As described above, in the dicing groove position measuring method of the present invention, the position of the groove formed on the same adhesive tape is measured. Measurement can be performed, and the effect of improving measurement accuracy is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a dicing apparatus to which a dicing groove position measuring method is applied in an embodiment of the present invention.

FIG. 2 is a perspective view showing an arrangement for measuring a position of a dicing groove in the embodiment of the present invention.

FIG. 3 is a perspective view showing a basic configuration of a dicing apparatus.

FIG. 4 is a diagram showing a frame and a semiconductor wafer held by an adhesive tape when processed in a dicing apparatus.

FIG. 5 is a diagram showing a chip arrangement on a semiconductor wafer.

FIG. 6 is a diagram showing a deviation between a cutting blade and a visual field of a projection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cutting blade (blade) 2 ... Stage 3 ... Stage moving mechanism 4 ... Projection means 5 ... Control part 100 ... Workpiece (wafer) 101 ... Frame 102 ... Adhesive tape

Continuation of the front page (56) References JP-A-63-128907 (JP, A) JP-A-64-53813 (JP, A) JP-A-57-80737 (JP, A) JP-A-54-93956 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/301 B28D 5/00

Claims (1)

(57) [Claims] 1. A cutting blade (1) rotating at a high speed, a stage (2) on which a semiconductor wafer (100) stuck on an adhesive tape (102) is mounted, and the stage (2) being moved. the semiconductor moving mechanism and (3), the groove by the cutting edge (1) is formed U
Projecting means (4) for projecting an image of the surface of the eha (100), wherein the position on the surface of the semiconductor wafer (100) is confirmed based on the image projected by the projecting means (4). In a dicing apparatus for performing a groove processing, a dicing groove position measuring method for measuring a correspondence relationship between a position of a groove processed by the cutting blade (1) and a position of an image projected by the projection means (4). , The adhesive tape (102) is attached to the semiconductor wafer (10).
0) having an outer diameter exceeding the outer diameter of the semiconductor wafer (1).
00), and the surface of the semiconductor wafer (100) is diced.
At this time, the viscosity exceeds the outer diameter of the semiconductor wafer (100).
Dicing on the adhesive tape (102), the semiconductor wafer
Of the adhesive tape (102) exceeding the outer diameter of (100)
A method for measuring the position of a dicing groove, wherein the position of the dicing groove is measured from a surface at a portion .