KR101266270B1 - Wafer inspection system and wager inspection method thereof - Google Patents

Abstract

The present invention relates to a wafer inspection system and method thereof.
In the present invention, the wafer inspection system for inspecting the surface defects of the wafer can automatically perform sequential inspection by driving the stage based on a predetermined macro, and the cell determined as the defect using the wafer map image. With respect to the coordinate information can be automatically obtained.

Description

Wafer Inspection System and wager inspection method

The present invention relates to a wafer inspection system and a method thereof, and more particularly, to a wafer inspection system and method for inspecting the surface defect of the wafer in a semiconductor process.

As the degree of integration of semiconductor devices increases recently, patterns formed on wafers become more and more fine, and the wafer diameter is large due to the development of wafer manufacturing technology. Increasing the integration density of the semiconductor device and the large diameter of the wafer also increase the defect inspection for improving the yield.

After semiconductor processing, surface defect inspection is performed to check for surface defects that may occur on the surface of the wafer during the process. The surface defect inspection is an inspection for checking scratches, particles, pattern abnormalities, and the like on the wafer surface.

As a method of inspecting the surface defect of a wafer, there exist an automatic inspection method using expensive automated equipment, and the manual inspection method which an operator visually inspects. In general, when the surface defect of the wafer is manually inspected after the semiconductor process, it is not necessary to have expensive automation equipment, and thus the equipment cost is relatively reduced. However, in the case of manual inspection, the user manually operates the microscope's manual stage and visually checks the defects of each cell, and in order to check the coordinates of the cells identified as defective, the number of cells must be counted one by one. The inspection process takes a lot of time. In addition, this results in a problem that results in an increase in the price of the semiconductor chip.

Disclosure of Invention An object of the present invention is to provide a wafer inspection system and method for minimizing time delay and improving inspection reliability in inspecting wafer defects.

A wafer inspection system according to an aspect of the present invention, the input unit; A stage on which the wafer is seated; A stage driver which controls the movement of the stage; A microscope mounted on top of the wafer to inspect the wafer; A camera for photographing at least one cell identified through the microscope; An image processor for image-processing and outputting an image of the at least one cell photographed through the camera; A memory that stores path information for sequentially moving the stage and a wafer map corresponding to the wafer; A display unit configured to display an image of the at least one cell photographed through the camera and an image of the wafer map; And controlling the stage driving unit to sequentially move the stage based on the path information when the macro is selected through the input unit, and when the specific cell of the image of the wafer map is selected as defective through the input unit, the wafer map. And a controller for storing the specific cell as defective.

According to the present invention, in the wafer inspection method, the inspection path is set to a macro in advance, and the surface defect inspection of the wafer is performed by using the set macro, so that the user conducting the inspection does not need to manually operate the stage for the inspection progress. In addition, since the coordinate information of the cell to be inspected is already registered in the macro, even if a bad cell occurs, there is no need to count the cells one by one to check the position of the cell, thereby reducing the delay time during the inspection process. This reduces the cost of inspection.

1 is a block diagram illustrating a wafer inspection system according to an exemplary embodiment of the present invention.
2 illustrates an example of arranging a calibration switch in a wafer inspection system according to an exemplary embodiment.
3 is a flowchart illustrating a wafer inspection method of the wafer inspection system according to an exemplary embodiment.
4 illustrates an example of displaying a wafer map image in a wafer inspection system according to an exemplary embodiment.
5 to 6 illustrate examples of a user interface that supports a user to directly select an inspection target cell in a wafer inspection system according to an exemplary embodiment.
7 is a flowchart illustrating a method of selecting an inspection target cell using a macro in a wafer inspection system according to an exemplary embodiment.
8 illustrates an example of a user interface for controlling macro execution in a wafer inspection system according to an embodiment of the present disclosure.
9 is a flowchart illustrating a macro generation method of the wafer inspection system according to an exemplary embodiment.
10 illustrates an example of a user interface for generating a macro in a wafer inspection system according to an embodiment of the present invention.
11 illustrates examples of macros generated by a user in a wafer inspection system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless otherwise stated.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

In addition, the suffix "module" and " part "for constituent elements used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

Hereinafter, a wafer inspection system and a method thereof according to an embodiment of the present invention will be described with reference to the accompanying drawings.

In this document, a wafer inspection system refers to a system for inspecting surface defects of a wafer in a semiconductor process.

Hereinafter, an operation of a wafer inspection system for performing a wafer inspection method according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

1 is a block diagram illustrating a wafer inspection system according to an exemplary embodiment of the present invention. 2 illustrates an example of arranging a calibration switch in a wafer inspection system according to an exemplary embodiment.

Referring to FIG. 1, the wafer inspection system 100 according to an exemplary embodiment may include a stage 110, a stage driver 120, an image generator 130, an image processor 140, a memory 150, The input unit 160, the display unit 170, and the controller 180 may be included. The components shown in FIG. 1 are not essential, so the wafer inspection system 100 may be implemented with more or fewer components.

The stage 110 functions as a wafer holder on which the wafer is seated.

Meanwhile, according to an embodiment of the present disclosure, a plurality of correction switches 211, 212, 213, and 214 may be provided in the stage 110 as illustrated in FIG. 2. Here, a limit switch may be used as the correction switch.

Each calibration switch 211, 212, 213, 214 is arranged to point to a particular X-axis or Y-axis coordinate of the wafer, and the relative position between each calibration switch 211, 212, 213, 214 and each cell of the wafer. May be used to calculate / correct the coordinates of each cell in the controller 180 to be described later.

To this end, the wafer needs to be seated correctly at a predetermined position on the stage 110, and when the wafer is seated correctly, the relative coordinates from each calibration switch 211, 212, 213, 214 to each cell are automatically determined and This can be used to calculate / correct coordinate information of each cell.

Referring back to FIG. 1, the stage driver 120 may include at least one motor (not shown) for moving the stage 110 along an X axis, a Y axis, or Θ. The stage driver 120 performs a function of aligning wafers by moving a stage based on a control input received from a controller 180 to be described later. That is, a function of controlling the movement of the stage 120 to align the wafer so that a specific region of the wafer is identified through a microscope.

In addition, when the correction switch is recognized while driving the stage 110, the stage driver 120 may notify the controller 180 to be described later that the correction switch is recognized. That is, when the stage 110 reaches the correction switch while driving the stage 110, the current stage position can be recognized, and the controller 180 can be notified of this.

The image generating unit 130 is installed on the stage 110, and includes a microscope (not shown) for checking the surface defect of the wafer, and a camera (not shown) for photographing the image seen through the microscope.

The image generator 130 performs a function of generating an image by photographing an image obtained through a microscope with a camera. Here, the image generated by the image generator 130 may be generated to include at least one cell positioned at an inspection position, that is, a position where an image can be acquired through a microscope, among the cells implemented in the wafer.

In the following, for convenience of description, the area of the wafer which can be acquired through the microscope by being positioned at the inspection position is referred to as an 'inspection region'. In addition, a cell included in the inspection area and capable of acquiring an image through a microscope is referred to as a 'test cell'. On the other hand, when the inspection area that can be inspected at one time is larger than one cell, one or more cells may be included in the inspection area.

The image processor 140 performs an image processing on the image generated by the image generator 130 and outputs the image to the controller 180.

The memory 150 may store a program for operating the wafer inspection system 100.

In addition, the memory 150 may store a wafer map including coordinate information of each cell implemented on the wafer. The wafer map may include whether each cell is normal / bad. In addition, the wafer map may further include the reason determined as defective for each cell determined as defective.

In addition, the memory 150 may store at least one macro different from each other.

Here, each macro includes path information for automatically moving the stage 110 to inspect the cells implemented on the wafer. The path information may be represented as a plurality of coordinate information to move the stage 110 to the inspection position.

The input unit 160 may receive a user input for controlling the operation of the wafer inspection system 100. The input unit 160 may include a key pad dome switch, a touch pad, a touch sensor, a jog wheel, a jog switch, a mouse, and the like.

The display unit 170 performs a function of displaying information processed by the wafer inspection system 100 or a user interface (UI) for controlling the wafer inspection system 100.

Meanwhile, when the input unit 160 is implemented as a touch sensor, the input unit 160 and the display unit 170 may be implemented as a touch screen by combining a mutual layer structure. In this case, the input unit 160 may receive input data based on a change in pressure applied to a specific point of the display unit 170 or a capacitance generated at a specific point of the display unit 170.

The controller 180 controls the overall operation of the wafer inspection system 100.

The controller 180 controls the stage driver 120 to move the stage 110 so that a specific region of the wafer is moved to the inspection position when the wafer is seated on the stage 110 and the surface defect inspection of the seated wafer is started. Can be.

Here, the specific area of the wafer to be placed at the inspection position may be directly selected by the user through the input unit 160 or automatically selected by a preset macro. In the latter case, the controller 180 may sequentially select the inspection area based on the plurality of coordinate information registered in the macro and the inspection order.

Meanwhile, when the correction switches 211, 212, 213, and 214 are recognized by the stage driver 120 during the inspection, the controller 180 is implemented on the wafer based on the X-axis coordinate or the Y-axis coordinate indicated by the recognized correction switch. It is also possible to correct the coordinate information of each cell. That is, by comparing the coordinate information calculated based on the recognized correction switch with the coordinate information of the area currently being inspected, the coordinate information of each cell can be corrected.

In addition, the controller 180 may display an image of at least one inspection target cell input through the image generator 130 and the image processor 140 through the display unit 170. Accordingly, the user inspecting the wafer may check the image of the inspection target cell displayed on the screen through the display unit 170 to check whether the corresponding cell is defective.

In addition, the controller 180 may display a wafer map image of the wafer seated on the stage through the display unit 170. When the user sets a specific cell as a defective cell using the wafer map image, the controller 180 automatically obtains coordinate information of the corresponding cell, and sets the corresponding cell on the wafer map as defective based on this. In addition, the cell is also marked as a defective cell in the wafer map image.

On the other hand, the controller 180 may mark the cells identified as defective in a different color from the normal cells on the wafer map image so that the user can intuitively distinguish between the normal and defective cells when marking the defective cells.

Hereinafter, the wafer inspection method of the wafer inspection system will be described in detail with reference to FIGS. 3 to 11.

3 is a flowchart illustrating a wafer inspection method according to an embodiment of the present invention. 4 illustrates an example of displaying a wafer map image.

Referring to FIG. 3, a wafer to be subjected to a surface defect inspection is seated on an upper stage of the stage 110 (S101).

Thereafter, the controller 180 obtains a wafer map image of the wafer seated on the stage 110 and displays it on the screen through the display unit 170 (S102). Here, the wafer map image is an image of the arrangement of each cell implemented on the wafer as shown in FIG.

Referring to FIG. 4, the wafer map image 400 may be divided into a plurality of cells in which a semiconductor chip is located and displayed. In addition, the cell 401 determined as defective in the surface defect inspection may be displayed in a color different from that of the normal cell 402 so as to intuitively distinguish it from the normal cell 402.

On the other hand, when an electro die sorting (EDS) test that inspects electrical characteristics of each semiconductor chip implemented on the wafer prior to the wafer surface defect inspection is performed, the wafer map image may reflect the EDS test result. . That is, the cells determined to be defective through the EDS inspection may be marked and displayed as defective cells on the wafer map image. In this case, the cell determined as defective through the surface defect inspection may be further marked on the wafer map image on which the defective cell by the EDS inspection is marked.

Referring again to FIG. 3, the controller 180 moves the stage 110 to move a specific region of the wafer to the inspection position (S103). That is, by controlling the stage driver 110, the stage 110 may be moved so that a specific region of the wafer is located at the inspection position. A method for selecting an inspection area in step S103 will be described in detail with reference to FIGS. 5 to 8 to be described later.

When the driving of the stage 110 is completed in step S103, the controller 180 synchronizes the wafer map image to the inspection area of the wafer (S104).

For example, the controller 180 may enlarge and display only the region corresponding to the inspection region currently being inspected through the microscope in the wafer map image, thereby synchronizing the wafer map image to the inspection region. In this case, the display unit 170 may display an image of the inspection area currently being inspected through a microscope and an area corresponding to the inspection area in the wafer map image.

Also, for example, the controller 180 may synchronize the wafer map image to the inspection area by displaying at least one cell included in the inspection area currently being inspected through a microscope on a wafer map image in a different color from the rest of the cells. have. In this case, the display unit 170 may display the image of the inspection region currently being inspected through the microscope and the entire wafer map image, and the region currently being inspected may be highlighted on the wafer map image.

 Accordingly, the user can intuitively grasp where the cell being inspected is located on the wafer.

Referring back to FIG. 3, when the user inputs a specific cell currently being inspected as a defective cell using the wafer map image (S105), the controller 180 automatically acquires coordinate information of the corresponding cell.

In addition, based on the obtained coordinate information, the corresponding cell is registered as a defective cell in the wafer map (S106).

For example, the controller 180 automatically obtains the coordinates of the corresponding cell from the corresponding wafer map when the user selects a specific cell determined as defective on the wafer map image using a mouse or the like and inputs the corresponding cell as the defective cell. do. In addition, the cell is registered as a defective cell in the wafer map.

In addition, the controller 180 marks the cell determined as defective on the wafer map image displayed on the screen as a defective cell (S107). In step S106, the controller 180 determines that the cell being inspected is defective by the user. If it is determined as a cell, the wafer map may be updated by setting the corresponding cell as a defective cell in the wafer map previously stored in the memory 150. In addition, the controller 180 may store a test result including coordinate information of cells registered as defective cells separately from the wafer map.

In addition, in step S106, the controller 180 may receive a reason determined as a failure from the user through the input unit 160, and store the received failure reason corresponding to the corresponding cell.

Meanwhile, the steps S103 to S107 may be repeatedly performed until the surface defect inspection on the wafer currently seated on the stage 110 is completed or the execution of the preset macro is finished (S108). .

When the surface defect inspection on the wafer currently seated on the stage 110 is finished (S107), the controller 180 corresponds to the wafer map reflecting the surface defect inspection result in accordance with the identification information of the wafer to be inspected and the memory 150. (S109).

Hereinafter, a method of selecting an inspection region from a wafer in step S103 of FIG. 3 will be described in detail with reference to FIGS. 5 through 8.

According to an embodiment of the present disclosure, the inspection area may be directly selected by the user through the input unit 160 in step S103.

When the user selects a specific cell on the wafer map image displayed on the screen using a mouse, the controller 180 may acquire coordinate information of the selected cell and select an inspection area based on the selected cell. That is, the inspection region is selected so that the selected cell is included in the inspection region.

In addition, when the user directly inputs coordinate information of a specific cell through the input unit 160, the controller 180 may select an inspection area based on this.

As described above, when the inspection region is selected using the coordinates of a specific cell, the inspection region may be set such that the selected cell is located at the center of the inspection region.

If the user inputs a moving direction through the input unit 160, the controller 180 may move the inspection area based on this. That is, at least one cell included in the current inspection area and a cell neighboring the cell may be moved to the inspection position.

5 through 6 illustrate examples of a user interface for directly selecting a test area by a user.

Referring to FIG. 5, the controller 180 displays the user interface 500 including the input regions 501 and 502 for receiving the X and Y axis coordinates of the cell through the display unit 170, respectively. In addition, when the X-axis coordinates and the Y-axis coordinates are input through the respective input areas 501 and 502, and the move button 503 is selected, the cells corresponding to the input X-axis coordinates and the Y-axis coordinates are input to the inspection area. The stage 110 may be moved to be included.

Referring to FIG. 6, the controller 180 displays, via the display unit 180, a user interface 600 including direction keys 601, 602, 603, and 604 indicating directions of movement of up, down, left, and right, respectively. Display. In addition, when any one of the direction keys 601, 602, 603, 604 is operated, the direction corresponding to the operated button is selected, and the inspection area is moved in the selected direction. For example, when the direction key 601 pointing upward is manipulated, the cell located in the upper direction among the cells included in the current inspection area and neighboring cells may be moved to the inspection position.

In addition, according to an embodiment of the present disclosure, the inspection region may be automatically selected by a predetermined macro in step S103.

When the user selects any one of the macros previously stored in the memory 150 through the input unit 160, the controller 180 sequentially checks the inspection area based on the coordinate information and the inspection order of a plurality of cells registered in the selected macro. You can choose.

7 is a flowchart illustrating a method of selecting an inspection area using a macro.

Referring to FIG. 7, the controller 180 selects one macro among preset macros through the input unit 160 (S201).

Thereafter, when the execution of the selected macro is requested (S202), the controller 180 sequentially drives the stage 110 in response to the selected macro (S203).

According to an embodiment of the present disclosure, each macro includes path information for automatically moving the stage 110, and the path information includes coordinate information and inspection order of a plurality of cells included in the inspection path.

Therefore, in step S203, the controller 180 may sequentially drive the stage 110 based on the coordinate information and the inspection order of the plurality of cells registered in the selected macro.

On the other hand, in step S203, the controller 180 may preset the time from the cell currently being inspected to the next cell during the execution of the macro, and control the stage 110 to move after the set time. . In this case, the time to stay in each cell can be set by the user.

Again, referring to FIG. 7, if the execution stop is requested through the input unit 160 while the macro is being executed (S204), the controller 180 stops executing the macro until the user is requested to re-execute the macro (S205). , S206). In addition, when the macro is re-executed, the macro is re-executed so that the inspection proceeds sequentially from the next cell of the cell currently being inspected.

8 illustrates an example of a user interface for controlling macro execution.

Referring to FIG. 8, the user interface 800 for controlling the execution of a macro corresponds to selection buttons 801, 802, 803, and 804 corresponding to different macros, and a function of executing and stopping a macro, respectively. To include buttons 805 and 806.

As described above, when inspecting a wafer using a macro, a user may automatically move the stage 110 using a macro without having to manually control the stage 110 each time the inspection is performed. . In addition, it is possible to stop or re-execute the inspection at a position desired by the user through the operation of the macro execution button 805 and the stop button 806.

Meanwhile, according to one embodiment of the present invention, a macro for wafer inspection may be set by a user.

Hereinafter, a method of generating a macro will be described in detail with reference to FIGS. 9 to 11.

9 is a flowchart illustrating a macro generation method according to an embodiment of the present invention. In addition, FIG. 10 illustrates an example of a user interface for generating a macro, and FIG. 11 illustrates examples of a macro generated by a user.

Referring to FIG. 9, the controller 180 enters a macro generation mode based on a user's control input (S301). Accordingly, the controller 180 displays a user interface for generating a macro through the display unit 170.

Using FIG. 10 as an example, the user interface 1000 for generating a macro includes buttons 1001 and 1002 for starting and ending generating a macro. The apparatus may further include an input area 1003 for inputting a time to move to the next cell when the macro is executed, and a button 1004 for selecting whether to store the time input through the input area 1003.

9, when the macro setting is started by the user (S302), the controller 180 generates a new macro. In addition, a cell to be added to the macro is selected based on a user input input through the input unit 160 (S303), and a macro is set based on the coordinate information and the selection order of the selected cell (S304).

The controller 180 continuously updates the macro by repeatedly performing steps S303 and S304 until the macro setting is completed by the user (S305). That is, the macro is updated by continuously adding cells selected by the user to the macro until the macro setting is completed.

When the end of the macro setting is requested, the macro setting is terminated and a macro including cells added up to now is stored in the memory 150 (S306).

In step S303, the user can select a cell added to the macro by various methods.

For example, a user may sequentially register at least one cell to a macro by using direction keys 601, 602, 603, and 604 used to select a cell to be inspected during a defect inspection.

Also, for example, the user may select cells added to the macro by sequentially selecting at least one cell on the wafer map image using a mouse or the like.

11 shows examples of macros set by a user based on the above-described methods.

According to the wafer inspection method according to an embodiment of the present invention described above, by setting the inspection path to a macro in advance and performing a surface defect inspection of the wafer using the set macro, the user performing the inspection stages for the inspection progress. There is no need to manipulate it manually. In addition, since the coordinate information of the inspection target cell is already registered in the macro, even if a bad cell occurs, it is not necessary to count the cell one by one to check the position of the corresponding cell.

Therefore, there is an effect of reducing the delay time in the inspection process, thereby reducing the inspection cost.

The embodiments of the present invention described above are not only implemented by the apparatus and method but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded, The embodiments can be easily implemented by those skilled in the art from the description of the embodiments described above.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings, and all or some of the embodiments may be selectively combined so that various modifications may be made.

Claims (8)

An input unit;
A stage on which the wafer is seated;
A stage driver which controls the movement of the stage;
A microscope mounted on top of the wafer to inspect the wafer;
A camera for photographing at least one cell identified through the microscope;
An image processor for image-processing and outputting an image of the at least one cell photographed through the camera;
A memory that stores path information for sequentially moving the stage and a wafer map corresponding to the wafer;
A display unit configured to display an image of the at least one cell photographed through the camera and an image of the wafer map; And
When the macro is selected through the input unit, the stage driving unit is controlled to sequentially move the stage based on the path information, and when the specific cell of the image of the wafer map is selected as defective through the input unit, Control unit for storing the specific cell as defective
Wafer inspection system comprising a. The method of claim 1,
The path information includes coordinate information of a plurality of cells for moving the stage,
When the controller enters the macro generation mode, the controller generates the macro based on the coordinate information and the selection order of a plurality of cells sequentially selected from the image of the wafer map. The method of claim 1,
The stage has a plurality of correction switches respectively corresponding to different X-axis coordinates or Y-axis coordinates,
The controller may be further configured to recognize the correction switch of any one of the plurality of correction switches through the stage driver, and compare the wafer with a cell located at a current test position and an X-axis coordinate or a Y-axis coordinate corresponding to the correction switch. Wafer inspection system, characterized in that to correct the coordinate information of a plurality of cells implemented on the image. The method of claim 1,
The control unit is a wafer inspection system, characterized in that for marking the image of the wafer map in a different color than the other cells recognized as a normal normal input cell. The method of claim 1,
And the control unit controls the display unit to enlarge and display only an area corresponding to the at least one cell in the image of the wafer map in synchronization with at least one cell identified through the microscope. The method of claim 1,
And the control unit controls the stage driving unit to move the selected cell to an inspection position when one cell is selected from the image of the wafer map through the input unit. The method of claim 1,
And the controller controls the stage driver to move a cell corresponding to the input coordinate information to a test position when coordinate information is input through the input unit. The method of claim 1,
When the moving direction is selected through the input unit, the control unit controls the stage driving unit to move a cell corresponding to the selected moving direction to a test position among a plurality of cells neighboring a cell currently being inspected. system.

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