JPH07321181A - System for teaching of automatic setting key pattern - Google Patents

Abstract

PURPOSE:To provide a teaching system for teaching automatic setting of key pattern which enables automatic theta alignment, magnification setting, conversion to CH2, etc., when dicing a semiconductor wafer. CONSTITUTION:The title system is constituted of a street cross designation step wherein a surface of a semiconductor wafer is imaged by an optical means and an operator designates street cross, a key pattern automatic extruding step wherein a proper pattern is automatically extruded as a key pattern from a surface of a semiconductor wafer and an operator call step for letting an operator know that an operation is finished after a key pattern is extruded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key pattern automatic setting teaching system for dicing a wafer with a precision cutting device such as a dicing device.

[0002]

2. Description of the Related Art A semiconductor wafer is diced along a street formed on its surface by a precision cutting device such as a dicing device, and divided into individual IC chips and the like. Prior to dicing, alignment is performed so that the rotary blades and the streets coincide with each other. This alignment is generally performed by pattern matching as disclosed in Japanese Patent Publication No. 3-27043. In this pattern matching, a characteristic point on the wafer is set as a key pattern, a positional relationship (distance) with the street is detected in advance, and is registered in the CPU as alignment key pattern information, and the wafer is imaged by an image pickup means such as a microscope. The surface is imaged, scanned based on the digitally converted image, the position of the street is detected by detecting the same pattern as the key pattern, and the rotating blade and the street are matched. Therefore, in the key pattern, it is necessary to set the most characteristic part as the key pattern, and a mistaken setting of the key pattern causes misalignment and hinders the execution of dicing.

[0003]

Conventionally, when setting a key pattern, an operator sets a portion of the wafer surface which is considered to be the most characteristic of intuition and experience while looking at the projected image as a key pattern. It was However, with this method, there is room for improvement because it is easy to make a mistake in setting the key pattern because it is done manually. Therefore, the present applicant has developed an automatic precision positioning system having a key pattern automatic setting means as disclosed in Japanese Patent Laid-Open No. 61-204716. This technique captures an image of the wafer surface with an image capturing means, calculates a plurality of pixel density dispersion values of a predetermined area (area suitable as a key pattern) based on the image signal converted into a digital signal, and calculates the dispersion value of the calculated dispersion values. The system is based on the automatic setting of a relatively high variance value as a key pattern. Although this system eliminates key pattern setting errors, θ adjustment, macro-micro ratio setting, CH ₂
There is a new problem that the operation is inefficient because it requires an operator's operation to convert to, and the operator could not leave the place until the work was completed. occured.

[0004]

As means for technically solving the above-mentioned problems, the present invention provides a street cross designating step (step 1) in which the surface of a semiconductor wafer is imaged by optical means and a street cross is designated by an operator. 1
Step), an automatic key pattern extraction step that automatically extracts a suitable pattern as a key pattern from the surface of the semiconductor wafer, and an operator call step that notifies the operator that the work is completed after the extraction of the key pattern is completed. (A fourteenth step) and the key pattern automatic setting teach system is made into the gist. The key pattern automatic extraction step is a second step of extracting a temporary key pattern and correcting the angular deviation between the street and the hairline based on the key pattern, and at least the one divided by the street.
Eighth extraction step of optically scanning one area to extract an appropriate portion as a key pattern, ninth step of locating other intersecting streets on the hairline, and at least one area divided by the streets And a thirteenth step of extracting an appropriate portion as a key pattern, the extracting step imaging the semiconductor wafer at a relatively low magnification and optically scanning the macro. Including a fifth step of extracting an appropriate portion as a key pattern, and an eighth step of imaging a semiconductor wafer at a relatively high magnification and optically scanning to extract an appropriate portion as a micro key pattern , A temporary key pattern is extracted between the ninth step and the thirteenth step, and the street and hair are extracted based on the key pattern. The correcting the angular deviation between the in-1
0 step is intervened, after the 14th step, it is confirmed whether the positional relationship between the key pattern extracted in the 13th step and the street is accurate, and if it is not accurate, fine adjustment is performed by the operator. The 15th step and the 9th step are performed in reverse to position the street on the hairline, the 16th step, and the positional relationship between the key pattern extracted by the 5th step and the 8th step and the street is accurate. 17th step of checking if there is any and finely adjusting by an operator if it is not accurate.

[0005]

[Operation] The operator only needs to specify the street cross, later θ adjustment, macro / micro magnification setting, CH ₂
Since the conversion to the key is automatically performed and the operator is called after the automatic setting of the key pattern is completed, it is possible to improve the workability by opening the operator from the front of the machine.

[0006]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an example of a dicing device.
The wafer with a frame pulled out from the cassette 2 to the standby area 3 by the carry-in / carry-out means 1 is carried to the chuck table 5 by the carrying means 4 having a swing arm, and the chuck table 5 is moved to the alignment means 6 for alignment. Cutting means 7 made with a rotating blade
Is diced by.

The key pattern used in the alignment must be extracted in advance, but the key pattern extraction in the present invention is performed in the order of processing steps as shown in FIG. First, the first step is street cross designation, which is performed by the operator operating the operation panel 8 as in the conventional case. That is, as shown in FIG. 3, the chuck table 5 is moved to position the wafer W directly under the microscope (imaging means) 6a, and as shown in FIG. 5, the horizontal street line CH ₁ and the vertical street line CH ₁ are arranged. An appropriate portion P where ₂ (see FIG. 4) intersects is designated on the monitor 9.

The second step is the θ adjustment of CH ₁ , but conventionally, the street CH ₁ displayed on the monitor 9 and the hairline L displayed on the monitor 9 are exactly parallel as shown in FIG. Although the operator operates the operation panel 8 to adjust the angle (θ) so as to coincide with, the present invention automatically does this. In order to perform this θ adjustment automatically, a temporary key pattern k is set by "key pattern automatic setting" for a characteristic part on the screen, and pattern matching is performed based on the temporary key pattern k. It is possible to use the technique disclosed in Japanese Patent Application No. 4-242599, which detects the continuity of the same pattern k as the temporary key pattern k, calculates the deviation of the angle (θ) with the hairline L, and adjusts the θ. Good. Alternatively, a corner of a chip such as an IC may be set as a temporary key pattern by an operator and registered in advance as a temporary key pattern.

The third step is a low magnification setting of the image pickup means, which was conventionally performed by the operator setting the magnification of the image pickup means to a relatively low magnification as shown in FIG. 7, but in the present invention, this is set. A low magnification and a high magnification are determined in advance and automatically selected by selecting them.

The fourth step is the first start,
In the past, the operator pressed the key pattern automatic setting button to start, but in the present invention, Q
And make it automatically.

The fifth step is the (macro) key pattern automatic setting, in which the CPU automatically sets the key pattern at a low magnification by the key pattern automatic setting means disclosed in Japanese Patent Laid-Open No. 61-204716. ,register.

The sixth step is to set the high magnification of the image pickup means. Conventionally, the operator has set the magnification of the image pickup means to a relatively high magnification as shown in FIG. 8, but in the present invention, this is predetermined. It is automatically performed by selecting the high magnification.

The seventh step is the second start,
In the prior art, too, the operator started the automatic setting of the key pattern, but in the present invention, Q is automatically issued by the high magnification setting.

The eighth step is the (micro) key pattern automatic setting, in which the CPU automatically sets the key pattern at a high magnification by the key pattern automatic setting means disclosed in Japanese Patent Laid-Open No. 61-204716. ,register.

The ninth step is the positioning of the CH ₂ street. Conventionally, the operator rotates the chuck table 5 by 90 degrees and operates the operation panel 8 so that the CH ₂ street coincides with the hairline L. However, in the present invention, this is automatically performed by utilizing the X and Y coordinate conversion.

The tenth step is the θ ₂ adjustment of CH ₂ , and as shown in FIG. 9, as in the case of the θ ₁ adjustment of CH ₁ , the conventional CH ₂ street displayed on the monitor 9,
The operator operated the operation panel 8 to adjust the angle (θ) so that the hairline L displayed on the monitor was aligned in parallel.
It is done automatically as in step.

The eleventh step is to set the magnification of the image pickup means. As shown in FIG. 10, the operator conventionally sets the magnification of the image pickup means to a relatively high magnification, but in the present invention, this is also predetermined. It is automatically performed by selecting the high magnification.

The twelfth step is the third start, which is conventionally started by the operator, but in the present invention, Q is issued by the high magnification setting and the start is automatically started.

The thirteenth step is CH ₂ (micro) key pattern automatic setting, in which the CPU automatically sets the key pattern at a high magnification by the key pattern automatic setting means disclosed in Japanese Patent Laid-Open No. 61-204716. Set and register.

The fourteenth step is an operator call, and the operator is notified by an alarm sound or a warning light that the above steps have been completed. Therefore, until then, the operator may be away from the front of the apparatus, and there is no need for care and labor can be saved.

The fifteenth step is to confirm and adjust the position of the CH ₂ key pattern and the CH ₂ street, which is C
The operator confirms the distance between the H ₂ street and the key pattern, and if the distance does not match the registered value, finely adjusts.

The 16th step is the positioning of the CH ₁ street, and after automatically rotating the chuck table 90 degrees, the CH ₁ street is aligned with the hairline L by utilizing the X and Y coordinate conversion.

The 17th step is to confirm and adjust the position of the CH ₁ key pattern and the CH ₁ street, and the operator confirms the distance between the CH ₁ street and the key pattern. If the distance does not match the registered value, fine adjustment is performed. .

The steps are completed in this way, and it takes about 4 minutes from the first step to the end, but conventionally, the frequency of steps operated by the operator is high, that is, the first, second, third, fourth, and so on in FIG. 6, 7, 9, 10, 11, 12,
The steps 15, 16, and 17 are processes performed by the operator. The intervention by the operator also serves as a confirmation action by the monitor, but in such a state, the operator cannot be separated from the device, which causes the operator to be restrained.

However, in the present invention, as described above, the process (operation) by the operator which also serves as the intermediate checking action is automated, and the checking action is performed only in the last fifteenth to seventeenth steps. The operator is released during the processing time in steps 2 to 13 to improve the efficiency.

Further, in order to inform the operator who has left the apparatus that the processing up to the 13th step has been completed, an operator call by an alarm device such as a buzzer or a flashing light is required.

When a macro or micro key pattern is required, as disclosed in Japanese Examined Patent Publication No. 3-27043, there is a case in which the pattern matching processing time is greatly shortened. It is not limited.

[0028]

As described above, according to the present invention,
In the alignment process of dicing of semiconductor wafers, etc., conventional operator operations such as θ adjustment, macro / micro ratio setting, and conversion to CH ₂ can be automatically performed. It has the effect of improving workability by opening it from the front.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a dicing device.

FIG. 2 is an explanatory diagram showing a step sequence of an alignment process according to the present invention.

FIG. 3 is an explanatory diagram showing a state in which a semiconductor wafer is positioned on a microscope (imaging unit).

FIG. 4 is a top view of a semiconductor wafer held by a frame.

FIG. 5 is an explanatory diagram showing designation of street crosses.

FIG. 6 is an explanatory diagram showing a θ adjustment state.

FIG. 7 is an explanatory diagram showing a macro key pattern setting state of CH ₁ .

FIG. 8 is an explanatory diagram showing a micro key pattern setting state of CH ₁ .

FIG. 9 is an explanatory diagram showing a θ-adjusted state of CH ₂ .

FIG. 10 is an explanatory diagram showing a CH ₂ micro key pattern setting state.

[Explanation of symbols]

1 ... carry-in / out means 2 ... cassette 3 ... standby area
4 ... Conveying means 5 ... Chuck table 6 ... Alignment means 6a ... Microscope 7 ... Cutting means 8 ... Operation panel 9 ... Monitor

Claims (5)

[Claims] 1. A street cross designating step (first step) in which an operator images a surface of a semiconductor wafer and a street cross is designated by an operator, and an appropriate pattern is automatically created from the surface of the semiconductor wafer as a key pattern. A key pattern automatic setting teaching system comprising an automatic key pattern extraction step for extraction and an operator call step (fourteenth step) for notifying the operator that the work is completed after the extraction of the key pattern is completed. 2. The automatic key pattern extraction step is
The second method of extracting a temporary key pattern and correcting the angular deviation between the street and the hairline based on the key pattern
And an eighth extraction step of optically scanning at least one area divided by streets to extract an appropriate portion as a key pattern, and a ninth step of positioning other intersecting streets on the hairline. The automatic key pattern setting teaching system according to claim 1, further comprising: a thirteenth step of optically scanning at least one area partitioned by streets to extract a suitable portion as a key pattern. 3. The extracting step comprises a fifth step of imaging a semiconductor wafer at a relatively low magnification and optically scanning to extract an appropriate portion as a macro key pattern; and a semiconductor wafer at a relatively high magnification. 8. The key pattern automatic setting teach system according to claim 2, further comprising: an eighth step of imaging and optically scanning to extract an appropriate portion as a micro key pattern. 4. A tenth step of extracting a temporary key pattern between the ninth step and the thirteenth step and correcting the angular deviation between the street and the hairline based on the key pattern is interposed. The automatic key pattern setting teach system according to claim 2. 5. A fifteenth step after the fourteenth step, which confirms whether the positional relationship between the key pattern extracted in the thirteenth step and the street is accurate, and if not, finely adjusts by the operator. Then, the ninth step is performed in reverse to position the street on the hairline, the sixteenth step, and whether the positional relationship between the key pattern extracted by the fifth step and the eighth step and the street is accurate. 17. A key pattern automatic setting teaching system according to claim 2, further comprising a seventeenth step of confirming and finely adjusting by an operator if it is not accurate.