JPS611034A - Pattern inspecting device for wafer chip - Google Patents

Abstract

PURPOSE:To semiautomatically readily perform the inspection of a chip pattern by detecting and storing a method of moving a stage in the row direction of a chip pattern array in a controller of a device. CONSTITUTION:A wafer 1 is placed on a stage 3, and a special A in a chip pattern at one end of a certain row is disposed at the center of a visual field of an inspecting microscope. When the stage 3 is moved in X- and Y-directions so that the special point B in the chip pattern at the other end of the row is disposed at the center of the visual field of the microscope, a controller 6 detects and stores a method of moving the stage 3 in the row direction of the chip pattern array. Then, the distance lx between the adjacent pattern is input, the chip pattern of one end of the certain row is merely brought into the inspecting position, thereby sequentially automatically feeding the chip pattern to be inspected to the inspecting position up to the chip pattern of the other end of the row.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention enables visual inspection of chip patterns formed on a wafer to detect one of the chip patterns arranged in rows and columns on the wafer by a simple initial operation. The ratio of the amount of movement in the X and Y directions for moving the stage so that multiple chip patterns belonging to a row come to the inspection position sequentially is detected, and this ratio and the distance between adjacent chips known for the type to be inspected are calculated by the equipment. By storing it in the control unit, if the chip pattern at one end of one row on the wafer is brought to the inspection position,
The present invention relates to a wafer chip pattern inspection apparatus in which the stage automatically moves sequentially after that so that all chip patterns belonging to that row are sent to the inspection position one after another.

[Conventional technology]

Conventionally, as a visual inspection method for chip patterns within a wafer, the operator inputs all inspection positions (CP controlling the inspection equipment).
(stored in U memory) was specified. However, this method is time consuming and inefficient when a large number of chips are specified, such as when testing all chips. As a countermeasure to this problem, Japanese Patent Publication No. 54-13749 proposes a method in which a chip group to be inspected consisting of a large number of chips is divided into a plurality of rectangular blocks, and the positioning A method is disclosed in which a program automatically controls an inspection apparatus by inputting the origin, the block size indicated by the number of chips in the X-Y direction, and the number of blocks. When a wafer on which a chip pattern has been formed by photolithography is placed on a stage whose position can be precisely adjusted for inspection, the X and Y movement directions of the stage and the chips arranged in rows and columns on the wafer are detected. The row and column directions of the pattern may not match, and there may be some angular error between them. The method disclosed in the above-mentioned patent publication does not take this kind of case into account; instead, it is necessary to establish in advance a procedure for moving the stage correctly so that the chips are sequentially sent to the inspection position. Alternatively, there is a problem that the effect cannot be achieved unless the angle error is corrected in advance.

[Problem that the invention seeks to solve]

The present invention can be applied to a simple initial operation when a wafer is placed on an inspection stage and there is a direction error between the X-Y movement direction of the stage and the direction in which chip patterns are arranged in rows and columns on the wafer. The inspection equipment itself detects and memorizes the movement of the stage to sequentially send the chip patterns belonging to one row on the wafer to the inspection position, and simply inputs the known distance between adjacent chips for the product to be inspected. To provide a wafer chip pattern inspection device in which, when a chip pattern at the end of a certain row is manually brought to an inspection position, all chip patterns belonging to that row are automatically sent to the inspection position one after another. Objective 2: 6.; [Means for solving the problem] There is a directional error between the X and Y movement directions of the stage and the matrix arrangement direction of the chip patterns on the wafer. In case,
After bringing the chip pattern at one end of a row to the inspection position (a specific point within the chip pattern is in the center of the field of view of the inspection microscope), move the stage so that the chip pattern at the other end of the row is at the inspection position. If you move in the X and Y directions,
From the amount of movement at this time, the ratio of the amount of movement in the X and Y directions to move the stage in the row direction of the chip pattern can be determined.The control section of the device detects and stores this ratio, and from then on, the stage will always be moved correctly. It becomes possible to move in the row direction of the chip pattern array. This is a major feature of the present invention. If you additionally enter the known distance between adjacent chips for the test type, when you manually bring the chip pattern at one end of a row to the testing position, the device itself will automatically scan all chip patterns belonging to that row. Chip patterns can be sequentially sent to the inspection position.

[Effect]

A method for detecting the ratio of the amount of movement in the x and y directions for moving the stage in the row direction of the chip pattern array on the wafer despite the presence of angular errors will be explained with reference to FIG. 1(a). This figure shows a state in which the wafer 1 is placed on the stage 3. In the figure, the Y-axis and Y-axis indicate the X and Y movement directions of the stage 3. The row direction of the array of chips 2 on the wafer is inclined with respect to the Y axis of the stage 3 by an angular error. As an initial operation, after placing a chip pattern at one end of a row consisting of a relatively large number of chip patterns at the inspection position (a specific point A(X, ,
Place Yρ at the center of the field of view of the inspection microscope (<), so that the chip pattern at the other end of the row is at the inspection position (specific point B (X, Y2) in this chip pattern is the center of the field of view of the microscope). When the stage is moved in the X and Y directions, the angle between the Y axis of the stage and the row direction of the chip pattern array on the wafer is θ, and the amount of movement in the X and Y directions is x and y, respectively. Then, it is clear that y=tanθ·X. That is, if the stage 3 is always moved so that this equation holds true, the stage 3 will move in the row direction of the chip pattern array on the wafer 1 placed on the stage 3. That is, a plurality of chip patterns belonging to one row are automatically sent to the inspection position one after another.

Once the control unit of the apparatus has detected and memorized the method of moving the stage in the row direction of the chip pattern array, that is, the ratio of the amount of movement in the X and Y directions through the above initial operation, it can be used as shown as β in Fig. 1(a). The distance between adjacent chip patterns is known for the product to be inspected, so if you additionally input that value,
The control unit of the inspection device starts from the chip pattern where point A exists, automatically moves the stage by ρχ in the row direction until it reaches the chip pattern where the final point B exists.
All chip patterns forming this row are automatically sent to the inspection position one after another.

〔Example〕

FIG. 1(b) shows a schematic configuration of an embodiment of the present invention. As described above, when the initial operation is performed after placing the wafer 1 on the stage 3, the control unit 6 detects and stores the method of moving the stage in the row direction of the chip pattern array. After that, after inputting the above information (it is sufficient to input this input once for one type of wafer), simply bring one end of a certain row, for example the leftmost chip pattern, to the inspection position. The chip patterns to be tested are automatically sent to the testing position in sequence up to the rightmost chip pattern.

In this figure, 4a is an X-axis drive unit that moves the stage 3 in the X direction, 4b is an X-position detection unit that detects the position of the stage 3 in the X direction, 5a is a Y-axis drive unit that moves the stage 3 in the Y direction, 5b is a Y position detection unit that detects the position of the stage 3 in the Y direction. In the case shown in Figure 1(a), five chips constitute one row from the chip represented by point A to the chip represented by point B; The rows are repeated three times in the column direction. In such a case, enter the distance between adjacent chips in the column direction of the chip pattern arrangement, and then perform 1. When the inspection of the first row has started from point A and ended at point B, the operator can, for example by repeatedly pressing a button,
automatically sets stage 3 to t2. Automatically inspect the row starting from the chip immediately below the chip represented by point A by moving j in the column direction and in the row direction by the same total length as in the case of the row that just finished testing. It is also easy to start from scratch.

〔Effect of the invention〕

As described above, according to the present invention, a chip pattern formed on a wafer can be inspected easily and semi-automatically by an operator with only a few manual operations.

[Brief explanation of drawings]

FIG. 1(a) is a diagram for explaining an angular error correction operation according to the present invention, and FIG. 1(b) is a schematic diagram of an embodiment of the present invention. 1-wafer, 2-chip, 3-stage, 4a
-X-axis drive unit, 4b-X position detection unit, 5a-Y-axis drive unit, 5b-Y position detection unit, 6-.-control unit.

Claims (1)

[Claims] In a wafer chip pattern inspection system that performs visual inspection of wafers on which chip patterns are arranged in rows and columns in the photolithography process, the wafer is placed on a stage that can move in the X and Y directions, and multiple chip patterns are first inspected on the wafer. Place the specific point in the chip pattern at one end of the horizontal row in the center of the field of view of the inspection microscope, then move the stage so that the specific point in the chip pattern at the other end of the same row is in the center of the field of view of the microscope. to move the stage so that specific points in each chip pattern belonging to one row are sequentially brought to the center of the field of view of the microscope based on the amount of movement of the stage in the X and Y directions during that time. By detecting the ratio of the amount of directional movement and inputting and storing this ratio and the known distance between adjacent chip patterns in the row direction for the chip type into the control unit of the device, a specific point within the chip pattern at one end of one row can be determined. When placed at the center of the inspection microscope's field of view, the stage automatically moves so that all specific points in each chip pattern belonging to that row are brought to the center of the microscope's field of view one after another. A wafer chip pattern inspection device characterized by: