JP5039594B2 - Review device, inspection area setting support system, and defect image acquisition method - Google Patents

Description

  The present invention relates to a review apparatus that images a detected defect on a semiconductor wafer at high magnification, an inspection area setting support system that supports detection of a defect in the review apparatus, and a defect image acquisition method in the review apparatus.

  In the process of forming circuit patterns on semiconductor wafers in semiconductor manufacturing, defects such as manufacturing defects and adhesion of foreign substances are unavoidable, and inspections for defects such as manufacturing defects and adhesion of foreign substances and reviews after defect detection are performed. In addition, by applying the technology of optical pattern inspection equipment and scanning electron microscope (Scanning Electron Microscope) that irradiates white light and uses optical images to compare the same type of circuit patterns of multiple LSIs and extract defects, An SEM pattern inspection device that compares circuit patterns using an electron beam image with higher resolution than an optical image and extracts defects, or an enlarged image of a defect detected by the inspection device, and based on the feature amount of the defect A defect review device for classification (hereinafter referred to as a review device) has been put into practical use.

  In the review device, when specifying the defect position at the time of defect review detected by the appearance inspection device, (1) a mode in which a reference image is acquired in an adjacent chip and a defect is detected by a difference image (hereinafter referred to as a die inspection mode). (2) A mode in which a defect is detected from a repetitive pattern difference image in a repetitive pattern region (hereinafter referred to as a cell inspection mode), and a mode in which a defect is detected by a combination of the modes (1) and (2) (hereinafter referred to as a mixed inspection). The defect position is specified using any one of the modes), and after moving to the specific position, the defect image is acquired at a high magnification, the acquired image is displayed, and the review is performed.

  In the current review device, when the defect position is detected when performing the defect review detected by the pattern inspection device, the defect detected by the pattern inspection device can be detected in the cell inspection mode. It cannot be determined whether it exists on the non-repeated pattern, which cannot be detected in the cell inspection mode. For this reason, in the review device, defect detection is performed in a cell inspection mode that requires a short time for defect detection, and when defect detection in the cell inspection mode fails, it is determined as a defect on a non-repeated pattern, and cell inspection is performed. A mixed inspection mode in which defect detection is performed using a die inspection mode after the mode is used. However, in this defect detection method, defect detection in the cell inspection mode is performed once regardless of the position where the defect exists, so if there are many defects on the non-repeated pattern, the defect detection throughput of the defect review is increased. There was a problem of being lowered.

  Regarding the inspection of masks for transferring circuit patterns to semiconductor wafers, a technology that detects defects by changing the defect detection criteria for different areas of the pattern in consideration of differences in mask pattern design criteria is patented. It is described in Document 1. However, no mention is made as to whether or not a defect can be detected due to the difference in the inspection modes described above.

  Further, it is known that many defects occur at the end of the memory area in the memory area, which is a representative area of the repetitive pattern. In this case, if a non-repeated pattern region is adjacent to a repetitive pattern region, the non-repeated pattern may be recognized as a defect when a defect is detected in the cell inspection mode. The problem of lowering occurs.

JP-A-2-236406

  An object of the present invention is to solve the above-described conventional problems, and to improve the defect detection processing in the mixed inspection mode in the review apparatus, thereby preventing erroneous defect detection and improving the throughput of defect review work.

  To achieve the above object, according to an embodiment of the present invention, there is provided a review device for observing a defect of a wafer in which a semiconductor device is formed as a plurality of dies, a storage means for storing a design layout pattern of the die, and a design layout. A display for displaying a pattern, and an input tool for designating a partial area of the design layout pattern displayed on the display, and detecting a defect in the die for a partial area of the design layout pattern set by the input tool Is characterized by detecting defects under different conditions.

  According to an embodiment of the present invention, there is provided a storage means for storing a die design layout pattern in an inspection area setting support system connected to a review apparatus for observing defects on a wafer in which a semiconductor device is formed as a plurality of dies. A plurality of patterns having a repeatability among circuit patterns formed on a die, comprising: a display for displaying a design layout pattern; and an input tool for designating a partial area of the design layout pattern displayed on the display. When one unit is a cell, a part of the cell area in the design layout pattern displayed on the display is set with the input tool, so that a part of the cell area is a rectangular frame as a cell inspection area. The displayed and set cell inspection area is transmitted to the review apparatus.

  In addition, according to an embodiment of the present invention, in a defect image acquisition method in a review apparatus for observing defects on a wafer in which a semiconductor device is formed as a plurality of dies, the circuit device has repeatability among circuit patterns formed on the dies. When one unit of a plurality of patterns is a cell, it is determined whether or not there is a defect coordinate sent from the appearance inspection apparatus in the cell area, and if it exists, a defect detection is performed for the cell area. If there is no defect, defect detection is performed on the die area.

  According to the present invention, by improving the defect detection process in the mixed inspection mode in the review apparatus, it is possible to prevent detection of erroneous defects and improve the throughput of defect review work.

  Embodiments of the present invention will be described below with reference to the drawings. The review device is a device that first detects defects at a low magnification based on the coordinates of the defects on the semiconductor wafer sent from the inspection device, then images the defects at a high magnification, and confirms the characteristics of the defects. . When detecting defects at a low magnification, by using the repeatability of the pattern and comparing the image data with a defect with image data that has the same pattern and no defect, only the defect can be extracted. You can see if there is a defect. A plurality of dies having the same shape are formed on a semiconductor wafer, and one die has a region called a cell that repeats the same pattern, such as a memory mat, and uses a defect detection in a die and a defect detection in a cell separately. And time efficiency is good.

  FIG. 1 is a flowchart showing a procedure for acquiring a defect image at the time of defect review. The procedure shown in FIG. 1 is executed for one defect, and this is repeated for a plurality of defects. In an inspection area setting support system, which will be described later, a target area for detecting defects in the cell inspection mode is created and sent to the review apparatus. The review device determines whether the defect coordinates detected in the appearance inspection device are present in the target region where defects can be detected in the cell inspection mode or outside the region. If the cell inspection mode is out of the area, the die inspection mode is selected (step 10). Even if a defect exists outside the region where defect detection is possible in the cell inspection mode, conventionally, the defect determination processing was performed in the cell inspection mode at a low magnification. By performing the defect detection process in the die inspection mode without executing the inspection mode, the time required for defect detection can be shortened.

  When the cell inspection mode is selected for low-definition defect detection, the stage is moved to the defect coordinate position sent from the appearance inspection apparatus (step 11). Here, the defect position is focused at a low magnification (step 12), and then a low magnification defect image is acquired (step 13), and the defect coordinates on the review apparatus are determined from the acquired image (step 14). ). Since there is an error between the defect coordinate position sent from the appearance inspection device and the coordinate position when the image of the defect was acquired by the review device, in order to capture a high-magnification image of the defect with the review device Requires correction of the coordinate position. The inspection sample is moved to the defect coordinate position determined by the operation from step 11 to step 14 (step 21), focus adjustment for detection of the high-magnification defect image is performed (step 22), and the high-magnification defect image is acquired (step). 23) and the defect detection process is completed (step 24).

  Next, a case where the die inspection mode is selected will be described. When the die inspection mode is selected for detecting the low-magnification defect, the inspection sample is moved to the reference image acquisition position in the die inspection mode (step 15), the reference image acquisition is focused (step 16), and the die inspection mode is selected. A low-magnification defect image is acquired (step 17). In the defect inspection in the die inspection mode, the defect is detected by comparing the reference image with the image of the inspection target die. The sample is moved to the die having the defect coordinate position sent from the appearance inspection apparatus (step 18), the low-magnification defect image is acquired (step 19), and the die image including the acquired defect is compared with the reference image. Then, the defect coordinates are determined (step 20). Thereafter, the inspection sample is moved to the defect coordinate position (step 21), focusing for high-magnification image detection is performed (step 22), a high-magnification defect image is acquired (step 23), and the defect detection process is completed (step 23). Step 24).

  FIG. 2 is a configuration diagram of the inspection area setting support system. The inspection area setting support system 2 can be connected to the review apparatus or built in the review apparatus body to improve the defect detection throughput of the review apparatus. The inspection area setting support system 2 shown in FIG. 2 is an example when connected to a review device, and includes a display 3 that displays design layout data, and a control computer that can store design layout data and set coordinate data. 4 and an input tool 43 for an operator to input an instruction. The design layout data is stored in advance in the control computer 4 or is obtained by loading from a database via a network (not shown).

  The control computer 4 includes a storage means 40 for storing design layout data, a storage means 41 for storing designated coordinate data, a storage means 42 for storing inspection results in the inspection apparatus, and an operator who performs function selection and coordinate designation on the display 3. An instruction input tool 43 is provided.

  The display 3 includes a screen 30 for displaying design layout data, a data selection unit 31 for selecting design layout data to be displayed on the screen 30, operations such as display magnification change, guide map display, design cell frame display, and area coordinate data confirmation screen display. And a status display section 33 for displaying operation mode and coordinate information of the mouse position on the display section.

  On the screen 30 of the display 3, the design layout data stored in the storage means 40 can be displayed at an arbitrary magnification, and an arbitrary area of the design layout data being displayed can be displayed, and is connected to the control computer 4. These displays can be instructed by an input tool 43 such as a mouse.

  3 and 4 are screen views in which design layout data is displayed on the display 3. FIG. 5 is a screen diagram showing a state where an area is set on the design layout data, and FIG. 6 is a screen diagram displaying the area data set on the design layout data. In addition to the display of the design layout data on the screen 30 shown in FIG. 3, a display area 31 for the name of the design layout data and a process selection unit 32 are provided. The process selection unit 32 has a “cell frame” button 34 for selecting an inspection area, a “guide map” button 35 for displaying the entire design layout data of the die, and the display of the design layout data is enlarged or reduced. An “enlargement / reduction” button 36 and an “area setting” button 37 used for setting an area are displayed.

  Next, a method for designating an area on the design layout data on the screen 30 will be described. When setting the inspection area, a method of specifying an area on the screen as shown in FIGS. 4 and 5 by clicking the “area setting” button 37 of the process selection unit 32, as shown in FIG. There is a method of inputting and specifying coordinates.

  FIG. 4 shows a case where a repetitive pattern is displayed in the lower area and an irregular non-repetitive pattern is displayed in the other areas on the screen 30. Defect coordinates are displayed in the repetitive pattern area, for example, by a mark 53, and in order to make this area to be inspected, a cell area is set by specifying with two places on the lower left and upper right and the mouse pointer. Displayed in a cell frame 52.

  When the “guide map” button 35 on the screen 30 shown in FIG. 3 is clicked, an image 60 of the entire layout shown in FIG. 5 is displayed on the design layout data. An area 61 that is enlarged or reduced on the screen 30 is displayed in the overall layout 60, and the area displayed on the screen 30 can be recognized. It is also possible to move the design layout data displayed on the screen 30 by moving the mouse in the area 61 displayed in the overall layout 60. In this way, detailed setting is possible while enlarging or reducing the design layout data displayed on the screen 30 and confirming the entire design layout pattern.

  When the “area setting” button 37 on the screen 30 shown in FIG. 3 is clicked, the area data confirmation screen 6 in FIG. 6 is displayed. It is possible to set a defect detection area by inputting a coordinate value in an input box of the coordinate area 62. Also, a coordinate list 63 is displayed, and a list of coordinates of the area set up to now including the method shown in FIG. 4 is displayed. After setting the coordinates of the area, the set data is saved in the storage means 41 of the control computer 4 by clicking the “Save” button 65. Further, when the set coordinate data displayed in the coordinate list 63 is selected by clicking the mouse or the like and the “Delete” button 64 is clicked, the coordinate data is deleted. When the “Cancel” button 66 is clicked, the screen shown in FIG. 3 is restored.

  FIG. 7 is a screen diagram showing a state in which an area is set on the design layout data. The screen 30 shows a case where the repeated pattern area 70 and the non-repeated pattern area 71 are adjacent to each other. In the case of the cell inspection mode, the cell inspection mode setting area 72 is a cell inspection area. On the other hand, when defect coordinates are displayed as marks 74 at the boundary between the repeated pattern region 70 and the non-repeated pattern region 71 on this screen, which is a part of the cell inspection mode setting region 72, the cell inspection mode setting region 72 In the cell inspection mode when 72 is set, a defect cannot be detected. Further, in the die inspection mode, since the entire screen 30 is an inspection target in order to detect this single defect, it takes time, and in the case of a minute defect, there is a possibility that it cannot be detected with the magnification of the die inspection mode. There is. Therefore, an area including the defect indicated by the mark 74 is set as the defect detection setting area 73. Thereby, since a range smaller than the cell inspection mode setting area 72 is inspected, it becomes possible to detect a defect that cannot be detected in the cell inspection mode but takes time in the die inspection mode, and the throughput is improved.

  As a method of setting the inspection area without using the die design layout data, the area of the cell inspection mode may be specified by displaying an actual image. The size of the die is about 10 mm at most, while it is about 0.1 mm at most, so it is not possible to take an image of the entire die at one time. is necessary. On the other hand, since the design layout data is the entire layout of the die, there is an advantage that data processing such as display of the entire display and display of details is easy.

  As described above, according to the present invention, it is possible to prevent detection of erroneous defects and improve the throughput of defect review work by improving the defect detection process in the mixed inspection mode in the review apparatus.

The flowchart which shows the procedure of defect image acquisition. The block diagram of the test | inspection area setting assistance system for test | inspection apparatuses. The screen figure which showed the state which displayed design layout data. The screen figure which showed the design layout data display. The screen figure which showed the state which set the area | region on design layout data. The screen figure which displays the area | region data set on design layout data. The screen figure which showed the state which set the area | region on design layout data.

Explanation of symbols

2 Inspection area setting support system 3 Display 4 Control computer 30 Screen 52 Cell frame 53, 74 Mark 72 Cell inspection mode setting area 73 Defect detection setting area

Claims (10)

In a review apparatus for observing defects detected in a visual inspection apparatus that are defects of a wafer in which a semiconductor device is formed as a plurality of dies,
The review apparatus includes a die inspection mode for performing defect detection using a differential image of a plurality of images of a die region, and one unit of a plurality of patterns having repeatability among circuit patterns formed on the die. And having a mode for detecting a defect in combination with a cell inspection mode for detecting a defect using a difference image of a plurality of images of the pattern having repeatability,
Storage means for storing a design layout pattern of the die;
A display for displaying the design layout pattern;
An input tool for designating a partial area of the design layout pattern displayed on the display as a cell inspection area ;
In the cell inspection area, determine whether there is a defect coordinate sent from the appearance inspection device,
A review apparatus characterized by performing defect detection in the cell inspection mode if present and performing defect detection in the die inspection mode if not present . 2. The defect detection according to claim 1 , wherein after the defect detection in the cell inspection mode or the defect detection in the die inspection mode, the defect is imaged at a magnification higher than a magnification at the time of the detection. Review device. In Claim 1 , When the said defect coordinate exists in the boundary of the some pattern and the other area | region which has the said repeatability, the area | region containing the said defect coordinate is independent of the area | region of the said cell. A review device characterized by being set. In an inspection area setting support system connected to a review apparatus for observing defects detected in a visual inspection apparatus, which are defects of a wafer in which a semiconductor device is formed as a plurality of dies,
The review device includes a die inspection mode for performing defect detection using a differential image of a plurality of images in a die region, and one unit of a plurality of patterns having repeatability among circuit patterns formed on the die. And having a mode for detecting a defect in combination with a cell inspection mode for detecting a defect using a differential image of a plurality of images of the pattern having repeatability,
The inspection area setting support system
Storage means for storing a design layout pattern of the die;
A display for displaying the design layout pattern;
An input tool for designating a partial area of the design layout pattern displayed on the display ;
By a portion of the cell region of the design layout pattern displayed before Symbol display set by the input tool, a portion of the cell region is displayed in a rectangular frame as a cell inspection area,
Send the set cell inspection area to the review device ,
The review apparatus determines whether or not the defect coordinates sent from the appearance inspection apparatus exist in the cell inspection area. If the defect coordinates exist, the review apparatus performs defect detection in the cell inspection mode. inspection area setting support system characterized der Rukoto to perform defect detection by the die inspection mode. 5. The inspection area setting according to claim 4 , wherein the display marks the defect on the design layout pattern based on the coordinates of the defect sent from the inspection device that detects the defect. Support system. 6. The method according to claim 5 , wherein when the coordinates of the defect are present at a boundary between the cell area and the other area, an area including the coordinates of the defect is set independently of the cell inspection area. An inspection area setting support system characterized by this. In a defect image acquisition method in a review apparatus for observing defects detected in a visual inspection apparatus, which are defects of a wafer in which a semiconductor device is formed as a plurality of dies,
The defect image acquisition method in the review apparatus includes a die inspection mode in which defect detection is performed using a differential image of a plurality of images in a die region, and a plurality of patterns having repeatability among circuit patterns formed on the die. When one unit of the cell is a cell, it is a mode for detecting a defect in combination with a cell inspection mode for detecting a defect using a differential image of a plurality of images of the pattern having the repeatability,
A partial area of the die design layout pattern is set as a cell inspection area,
To the cell examination region, it determines whether the sent defect coordinates are present from the appearance inspection apparatus,
A defect image acquisition method comprising: performing defect detection in the cell inspection mode if present, and performing defect detection in the die inspection mode if not present. 8. The defect detection according to claim 7 , wherein after the defect detection in the cell inspection mode or the defect detection in the die inspection mode, the defect is imaged at a magnification higher than a magnification at the time of the detection. Defect image acquisition method. 8. The defect image acquisition method according to claim 7 , wherein the circuit pattern is a design layout pattern of the die. 8. The method according to claim 7 , wherein when the defect coordinates exist at a boundary between the plurality of patterns having the repeatability and other areas, the area including the defect coordinates is independent of the area of the cell. A defect image acquisition method characterized by being set.

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