JPS6085520A - Pattern inspecting method - Google Patents

Abstract

PURPOSE:To shorten the inspection time by moving an object to be inspected at first speed when the object is positioned at an inspecting section and moving it at second speed which is faster than the first speed when it is positioned at a section, which need not be inspected, in a pattern inspection device through which the object to be inspected loaded on an X-Y stage is scanned and inspected. CONSTITUTION:A mask 2 for manufacturing an IC is placed on a light-transmitting X-Y stage 1, the back thereof has a light source 5, the stage 1 is driven and the mask 2 is scanned by a Y-axis driving section 8 and an X-axis driving section 9 while a pattern on the mask 2 is detected by photoelectric detectors 3 and 4 fitted on the upper surface of the stage 1, and the defect of the pattern is inspected by a defect decision section 6. A microprocessor 7 is operated by a positional information from a stage position sensor 10 mounted near the stage 1, and the driving sections 8 and 9 are controlled severally. In the constitution, the speed of travel of the stage 1 is brought to fixed speed during the inspection of an effective pattern, and the stage 1 is moved at the speed faster than said speed at the location which is irrelevant to inspection.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention is particularly useful in improving the inspection speed when performing pattern scanning to determine the quality of the pattern, such as an appearance inspection machine for photomasks, printed circuit boards, and LSI wafers. butter/
Regarding inspection methods.

[Background of the invention]

Since the conventional photomask or LSI wafer visual inspection apparatus needs to detect fine patterns, the area a that can be inspected at once, as shown in FIG. 1, is much smaller than the entire screen A. Therefore, in order to inspect the entire surface, it is necessary to mechanically scan the stage on which the object to be inspected is placed. However, depending on the location of the object to be inspected, for example, there is no need to inspect it at all on the two-way line of an IC chip.In memory devices, etc., the memory pattern portion consists of a collection of very fine patterns. Although it is necessary to carry out a correspondingly fine inspection, since the pattern density is coarse in the vicinity of the bonding pad in the peripheral area, a correspondingly coarse inspection is acceptable. However, conventional inspection equipment thoroughly and precisely inspects areas that do not require inspection, such as scribe areas, regardless of the pattern density. For this reason, an inspection time that is not originally related to inspection performance is added, resulting in an increase in the overall inspection time.

[Purpose of the invention]

An object of the present invention is to provide a pattern inspection method that eliminates the waste of the conventional inspection methods described above and shortens inspection time.

[Summary of the invention]

In order to achieve the above object, the present invention has the following objectives:
0 [Embodiment of the Invention] An embodiment of the present invention will be described regarding a mask inspection machine for IC manufacturing. FIG. 2 is a schematic diagram in which a mask 2 to be inspected mounted on an XYX stage is illuminated with a light source 5, and a photoelectric detector 3,
After the notch turn on the mask 2 is detected in step 4, the XY stage 1 is driven and scanned, and the defect determining section 6 performs a pattern defect inspection on the entire surface of the mask. This XY stage 1
The drive method is to move the stage in the (+)Y direction by moving the X-axis moving part 9.
The end of the drive is driven by the Y-axis moving part 8! D (+)
Move one field of view (several tens to hundreds of microns) in the Y direction, then turn back to the Y direction (←) and move again (+) to the X direction in the Y direction.
It repeats the axis driving operation, and based on the position information from the stage position sensor 10, the microprocessor 7 controls the scanning start, end, and return, and performs constant speed, reciprocating movement in the Y direction, and step movement in the Y direction. The entire surface of the mask 2 is inspected.

As shown in Figure 6, the mask pattern is a regular pattern 11°12.13 in which each square constitutes one integrated circuit.
These are arranged in a basic pattern in the x, y, and y directions. FIG. 4 shows an enlarged version of FIG. 3. The field of view 14 of the photoelectric detector is, for example, 0.16 μm x 1
2Bμm, which is very small compared to the overall mask size, so the scanning shown by the arrow in Figure 4 is
The Y stage 1 is driven to carry out the plucking. At this time, the patterns actually used as an integrated circuit are portions 11 and 12, and the portion 15 is a dicing area for cutting during production of the integrated circuit and does not need to be inspected. The speed of inspection is second
This is determined by the performance of the illumination light source 5 shown in the figure, its optical system, photoelectric detectors 3, 4, defect determination section 6, etc. 5, and is not limited by the drive speed of the xY stage 1, so there are areas that do not require inspection. That is, in the portion indicated by 15 in FIG. 4, the stage speed is increased as much as possible to shorten the inspection time.

FIG. 5 is a diagram showing the speed of the X-axis of the XY stage 1 in one hour according to the present invention. 17, integrated circuit pattern 1
The speed during testing 2 is shown in section 18. That is, the X stage is driven at a speed of V during an effective slam test, and at a speed of V2 when not related to the test. Similarly, in the Y stage, when the photoelectric detectors 3 and 4 cover areas other than the effective pattern area, the speed can be increased to shorten the inspection time. Information on where the effective part of the pattern is located, such as chip spacing and dicing area dimensions, is stored in advance in the microprocessor 7 that controls the stage in FIG. 2, and the actual position is determined by the stage position sensor 10. You can easily distinguish by comparing the reading with 9.

In the above method, the dicing area 15 is used as an unnecessary part for inspection and is moved at high speed, but the density of the pattern is coarse.
In areas where detailed inspection is not required, it is also possible to increase the step feed amount in the Y direction to reduce inspection accuracy and shorten inspection time. This density information may also be stored in the microprocessor 7 in advance.

〔Effect of the invention〕

According to the present invention, for example, the stage movement speed is 2.5 mm.
In a mask inspection device that inspects at a speed of 10,100 mm x 100 per second, a mask of approximately 40
However, by increasing the speed in dicing area 15, this can be shortened by 2 seconds.Assuming that one scan moves 128 μm in the Y direction, and the entire scan area is 100 mmO, the overall reduction will be The time is 26 minutes, so a time reduction of 26 minutes is achieved.

[Brief explanation of the drawing]

Figure 1 is a plan view showing stage scanning for mask inspection;
Figure 2 is a conceptual diagram of the mask inspection machine, Figure 3 is a plan view showing the mask button arrangement, and Figure 4 is the mask pattern and XY
A partially enlarged view of FIG. 6 showing the scanning state of the stage and photoelectric detector, and FIG. 5 is a speed diagram of the XY stage of the present invention. 1... XY stage, 2... Mask, 6.4... Photoelectric detector, 7... Microprocessor, 8... Y-axis drive section, 9... X-axis drive section, 10.・・Stage position sensor, 11.12.1
3... Integrated circuit pattern, 14... Field of view of photoelectric detector, 15... Dicing area. Age 10 Figure 3 l

Claims (1)

[Claims] In a pattern inspection apparatus that scans and inspects an object to be inspected mounted on an xy stage, the XY stage is moved at a first speed when the object to be inspected is in an inspection area, and the object to be inspected is in an area not to be inspected. 1. A pattern inspection method characterized in that the pattern inspection method is configured to move at a second speed faster than the first speed when the pattern inspection method is at a second speed.