JP2000077487A - Wafer prober - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate position recognition errors by a method, wherein defective chips and non-defective chips are distinguished from each other in a wafer through image processing so as to discriminate the position of a target chip. SOLUTION: After a prescribed setup operation is carried out, a defective chip 3 is indicated, and the image pattern of the chip 3 is stored. Chips on a wafer 1 are image-recognized chip by chip in the direction of 6, starting from one located at the upper edge of the wafer 1 by a prober, the image of a chip is compared with the stored image pattern of the chip 3, and when it is found that the image of the chip differs much from the stored image pattern of the chip 3, the chip is discriminated as being a non-defective chip 2. Then, chips are image-recognized chip by chip in the direction of 7 starting from the left edge of wafer 1, the image of a chip is compared with the stored image pattern of the chip 3, and when it is found that the image of the chip differs much from the stored image pattern of the chip 3, the chip is discriminated as being a non-defective chip 2. With this setup, processes can be kept free of the effects of pattern printing errors and of differences in the instruments of the prober. Since a specific chip is not required to be provided on the wafer 1, a process where the specific ship is formed is not required to be provided additionally.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for recognizing a position of a measurement chip in a wafer prober used for inspecting a wafer.

[0002]

2. Description of the Related Art The prior art will be described below with reference to the drawings.

FIG. 1 shows a wafer 1 composed of complete chips 2 and incomplete chips 3. In the conventional method of recognizing the position of a measurement chip in a wafer prober, an operator instructs the wafer prober about the location of a base point and the location of a complete chip 2 for each product type, and thereafter, the location of the base chip 4 only when the product type changes. Only the measurement of the complete chip 2 was performed only by making the recognition.

[0004]

In the prior art, the number of man-hours for teaching the measurement location to the prober, the mis-training, or the man-hour for specifying the location of the base chip 4 every time the type is changed, the place specification error, and the like. In the case of a product having a small chip size, a position recognition error has occurred due to a pattern printing error in a process step and a dimensional error of the base chip 4 from the wafer center 5 due to a recognition error of the wafer center 5 of the prober itself.

An object of the present invention is to solve the above problems.

[0006]

A prober measurement area check characterized in that a defective chip 3 and a complete chip 2 are distinguished by image processing to determine a measurement chip position.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

First, a method of image processing will be described.

FIG. 1 shows a wafer 1 composed of complete chips 2 and incomplete chips 3.

The position of each chip is managed by X and Y addresses.

In a setup operation (teaching operation by an operator), the following is performed.

(A) Wafer center 5 of each existing prober
The position of the wafer center 5 is determined by the detection method.

(A) Alignment is performed by the wafer alignment method of each existing prober. As a result, the prober itself can develop a wafer map as shown in FIG.

(C) Incomplete chips 3 by the operator
Instruct.

The image pattern of the incomplete chip 3 is stored.

The following is the automatic operation of the prober.

(E) Direction 6 from the chip at the upper end of wafer 1
Then, image recognition is performed one chip at a time, and comparison with the pattern stored in (d) is performed.

(F) A chip having an image greatly different from the pattern stored in (d) is determined to be a complete chip 2.

(G) The direction 7 from the chip on the left end of the wafer 1
Then, image recognition is performed one chip at a time, and comparison with the pattern stored in (d) is performed.

(G) A chip having an image greatly different from the pattern stored in (d) is determined to be a complete chip 2.

(G) The operator specifies and stores the X address value of the leftmost complete chip and the Y address value of the uppermost complete chip.

(C) The chip (f) is assigned to the Y address (f).

(C) The X address of (g) is allocated to the chip of (g).

(S) The measurement area is developed based on (C) and (S).

The following is performed in the automatic operation.

(S) Wafer center 5 of each existing prober
The position of the wafer center 5 is determined by the detection method.

(C) Alignment is performed by the wafer alignment method of each existing prober. As a result, the prober itself can develop a wafer map as shown in FIG.

(G) Direction 6 from the chip at the upper end of wafer 1
Then, image recognition is performed one chip at a time, and comparison with the pattern stored in (d) is performed.

(T) A chip having an image greatly different from the pattern stored in (D) is determined to be a complete chip 2.

(H) The direction 7 from the chip on the left end of the wafer 1
Then, image recognition is performed one chip at a time, and comparison with the pattern stored in (d) is performed.

(T) A chip having an image significantly different from the pattern stored in (D) is determined to be a complete chip 2.

(T) Allocate the Y address of (G) to the chip of (T).

(G) The (x) chip is assigned to the (x) X address.

(N) Expand the measurement area based on (te) and (g).

Next, a method using a laser sensor will be described.

(D) Wafer center 5 of each existing prober
The position of the wafer center 5 is determined by the detection method.

(V) Alignment is performed by the wafer alignment method of each existing prober. As a result, the prober itself can develop a wafer map as shown in FIG.

(D) Direction 6 from the chip at the upper end of wafer 1
Shake the laser.

(H) The chip where a large change has occurred is determined to be a complete chip 2.

(C) Direction 7 from the chip on the left end of wafer 1
Shake the laser.

(H) The chip where a large change has occurred is determined to be complete chip 2.

(F) The operator specifies and stores the X address value of the leftmost complete chip 2 and the Y address value of the uppermost complete chip 2.

(F) Allocate the (no) chip to the (f) Y address.

(E) The X address of (f) is assigned to the chip of (h).

The measurement area is developed based on (M), (F), and (E).

The following is performed in the automatic operation.

(M) Wafer center 5 of each existing prober
The position of the wafer center 5 is determined by the detection method.

(M) Alignment is performed by the wafer alignment method of each existing prober. As a result, the prober itself can develop a wafer map as shown in FIG.

(M) Direction 6 from the chip at the upper end of wafer 1
Shake the laser.

(M) The chip where a large change has occurred is determined to be the complete chip 2.

(Y) Direction 7 from the chip on the left end of wafer 1
Shake the laser.

(U) A chip where a large change has occurred is determined to be a complete chip 2.

(Y) The chip (M) is assigned to the Y address (F).

(A) The X address of (F) is allocated to the chip of (U).

(I) The measurement area is developed based on (te) and (g).

[0056]

Since the present invention is a method as described above, the following effects can be obtained.

Since the distance from the wafer center is not used in recognizing the chip to be measured on the wafer, it is not affected by pattern printing errors in the process steps, differences in probers, etc.

Since there is no need to provide unique chips on the wafer, there is no need to increase the number of unique chip preparation steps, and the unit cost of the wafer is reduced. Further, the number of teaching steps for the chip to be measured on the wafer can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a chip configuration of a wafer for explanation of the present invention.

[Explanation of symbols]

 Reference Signs List 1 wafer 2 perfect chip 3 incomplete chip 4 base chip 5 wafer center 6 direction 7 direction

Claims (2)

[Claims] A wafer prober characterized in that an incomplete chip and a complete chip in a wafer are distinguished by image processing to determine a position of a measurement chip. 2. A wafer prober wherein a measurement chip position is determined by distinguishing an incomplete chip and a complete chip in a wafer by a laser sensor.