JPH02115753A - Reticle checking method - Google Patents

Abstract

PURPOSE:To shorten the check time by increasing the speed of a stage used for check of a peripheral pattern consisting of a coarse thin film pattern in comparison with a main body pattern consisting of a fine thin film. CONSTITUTION:The same original pattern data D1 as data used for generation of a reticle is stored on magnetic tapes 1-a to 1-c. This data D1 consists of main body pattern data (on the tape 1-a), process control module pattern data ( on the tape 1-b), and peripheral pattern data (on the tape 1-c). This data D1 is converted to a comparison signal D2 by a converting part 2. Respective pattern data stored on a tapes 1-a to 1-c are given as pattern information D3 to a stage controller 3, and an X-Y stage 5 on which a reticle 4 to be checked is placed is moved while changing the stage speed in accordance with information D3. An optical signal D4 of the actual reticle pattern obtained by an optical system 6 is converted to a comparison signal D5 by a photoelectric transducer 7 and is compared with the signal D2 by a comparing part 8, and the comparison result is outputted to an external output part 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reticle inspection method used in the manufacture of semiconductor integrated circuits.

(Prior Art) When manufacturing a semiconductor integrated circuit, in order to expose a predetermined element configuration pattern on a mask substrate or a semiconductor substrate, the pattern is placed on a glass substrate on which a metal such as chromium (Cr) is vapor-deposited. A so-called reticle, which is a mask formed with a magnification of ~10 times, is used. A method for reticle inspection in conventional methods.

There is a so-called database-based inspection method, which compares data of electrical signals of the reticle pattern obtained through a photoelectric conversion system with original pattern data when manufacturing the reticle.

FIG. 5 shows a schematic diagram of reticle inspection using the database method described above. Original pattern data (design data) D equivalent to the data used to create the reticle is stored on the magnetic tape 1. The design data includes a pattern for forming a predetermined integrated circuit (hereinafter referred to as a main body pattern), a process control module pattern for process management control (hereinafter referred to as a PCM pattern),
It is made up of data constituting an alignment mark pattern necessary for reduction projection exposure, a main pattern, and a frame pattern surrounding the PCM pattern (hereinafter referred to as one peripheral pattern). The original pattern data is converted into a comparison signal D2 in the conversion section 2. While the stage 5 on which the reticle 4 to be inspected is moved at a constant speed in the X and Y directions by the stage controller 3, an optical signal of the actual reticle pattern is obtained from the optical system 6 at regular intervals. Optical signal, ha,
It is converted into a comparison signal Ds by the photoelectric conversion section 7, compared with the comparison signal D2 of the original pattern data by the comparison section 8, and outputted to the external output section 9.

(Problem to be Solved by the Invention) However, in the conventional inspection method described above, the stage on which the reticle to be inspected is mounted is moved at a constant speed, and data comparison inspection is performed on all of the main pattern, PCM pattern, and peripheral pattern. The problem is that the inspection time is long because of the

The present invention solves the above-mentioned problems, and aims to provide a means for significantly shortening the inspection time while maintaining the conventional detection accuracy.

(Means for Solving the Problems) In order to achieve this object, the reticle inspection method of the present invention includes a database-based inspection method that includes a main body pattern,
The stage speed used for inspecting the PCM pattern is a conventional speed, and the stage speed used for inspecting peripheral patterns is set at a high speed.

(Function) Normally, the peripheral pattern of the reticle is one main body pattern, one PC
The required pattern accuracy is lower than that of the M pattern.

On the other hand, as the stage speed increases, pattern inspection accuracy decreases. Therefore, since the inspection of the main body pattern and the PCM pattern is carried out at the conventional stage movement speed, the inspection is highly accurate and the inspection time is the same. Inspection of peripheral patterns requires high-speed stage movement, which lowers inspection accuracy, but shortens inspection time. As described above, inspection time can be shortened by controlling the stage movement speed.

(Example) An example of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, original pattern data D1 equivalent to that used to create the reticle is stored on a magnetic tape 1.
-a to 1-c are stored. Original pattern data is 1
It is composed of main body pattern data (inside 1-a), PCM pattern data (inside 1-b), and nine peripheral pattern data (inside 1-c).

The pattern data is converted into a comparison signal D2 in the conversion section 2. According to our experiments, there is a relationship between stage movement speed and inspection accuracy as shown in FIG. 2. Figure 2 shows stage movement speed ratio (ratio to conventional speed)
This indicates that the inspection accuracy decreases as the value increases.

Information D3 (hereinafter referred to as pattern configuration information) about which area on the reticle each pattern data stored on the magnetic tapes 1-a to 1-c corresponds to and what the inspection speed is at that time is sent to the stage controller. Give to 3. At the start of the inspection, the X-Y
The stage 5 moves while changing the stage speed according to the pattern configuration information. The optical signal D4 of the actual reticle pattern obtained by the optical system 6 is converted into a comparison signal D5 by the photoelectric conversion section 7, compared with the original pattern comparison signal D2 by the comparison section 8, and outputted to the external output section 9.

FIG. 3 shows an example of the configuration of a reticle to be inspected.

An example of scanning of the X-Y stage 5 is shown. Original pattern data D
□ is main body pattern 10 and PCM pattern II.

Frame pattern 12. Alignment mark pattern 1
It is made up of data that makes up 3. First, the x-y stage 5 is moved in the X direction from point a until it reaches the point. Next, the stage is moved in the Y direction to point by the pattern width obtained by the optical system 6. By repeating the above steps, the stage scans the reticle up to one point Q. In the range surrounded by the reticle scanning area point abkQ, the PCM pattern 11 surrounded by the point cdfe and the main body pattern 10 surrounded by the point ghj i move the stage at the conventional speed. point cdf
The stage speed of the peripheral pattern except inside e and inside point ghj i is twice the conventional speed. In the case of this example, the inspection time was shortened to 6/10 by changing the inspection speed. Figure 4 shows the relationship between the ratio of high-speed inspection area and inspection time.
The high-speed inspection area occupancy rate is equivalent to 70%. area cd
The detection sensitivity of defects in areas other than fe and ghji decreases because the stage speed is increased, but the defect size that becomes a problem when performing reduction projection exposure using an existing reticle is the defect size of the 5-body pattern and the PCM pattern. Since the defect size of the peripheral pattern is much larger than that of the pattern, it is not a problem. For example, during 115 reduction projection exposure, if there is a defect of 2μIφ on the reticle in the main body pattern 10, it becomes a defect of 0.4μIφ, which affects the performance of the integrated circuit, but the positioning for reduction projection exposure is 3 to 4 in the alignment mark pattern I3 and the frame pattern 12 corresponding to the slit size that determines the reduction projection exposure area.
Defects of μmφ do not affect the performance of the integrated circuit.

(Effects of the Invention) As described above, the reticle inspection method of the present invention can significantly shorten the data verification inspection time while maintaining high detection sensitivity, and is greatly useful for shortening the reticle manufacturing process and semiconductor manufacturing period, and is useful for reducing the industrial Ishikawa It is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a reticle inspection method based on a comparison between a database and an actual chital pattern in an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between stage movement speed and inspection accuracy. Figure 4 is a plan view showing an example of the pattern configuration of a reticle to be inspected, Figure 4 is a graph showing the relationship between the occupancy of the stage high-speed inspection area and inspection time, and Figure 5-1 is a conventional database-based reticle inspection method. 4
6. This is a block diagram showing 14 configurations.
2... Original pattern data conversion unit, 3... Stage controller, 4... Reticle to be inspected, 5
...X-Y stage. 6... Optical system, 7... Photoelectric conversion section, 8... Signal comparison section, 9... External output section that outputs comparison information. 2nd = [- Figure 4 Figure 10 t I$ pattern

Claims (1)

[Claims] The base body is held on a moving body movable in the X-Y direction, the thin film pattern formed on the base body is converted into electrical signal data, and the designed pattern data and the signal data are compared. Area A on the substrate where it is necessary to detect damage to the thin film pattern on the substrate, area A on the substrate where it is necessary to detect damage to the fine thin film pattern, and region A on the substrate where it is necessary to detect damage to the coarse thin film pattern. A reticle inspection method characterized by dividing an inspection area into a region B, and making the moving speed of the moving object in the region B higher than the moving speed of the moving object in the region A.