JPH09265175A - Mask for inspecting wear and method for inspecting circuit pattern wear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly inspect the wear of circuit patterns formed on a mask. SOLUTION: The inspection patterns of the mask for inspecting the wear having the inspection patterns for inspecting wear consisting of the pattern widths of the same direction as the direction of the narrowest pattern among the circuit patterns and equal thereto in the prescribed position of the inner parts of the alignment marks on the same plane as the plane formed with the circuit patterns are irradiated with a luminous flux and the scattered light generated according to the wear of the inspection patterns is received. The wear of the inspection patterns is inspected in accordance with the scattered light received in such a manner. The wear of the inspection patterns is judged as the wear of the circuit patterns, by which the mask for inspecting the war capable of rapidly inspecting the wear of the circuit patterns and the method for inspecting the wear of the circuit patterns are embodied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wear inspection mask and a circuit pattern wear inspection method, for example, a wear inspection mask and circuit for detecting the wear state of a circuit pattern formed on the mask when transferring to an integrated circuit or the like. It is suitable for application to a pattern wear inspection method.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor manufacturing process for manufacturing a large scale integrated circuit or a manufacturing process for a liquid crystal display device, a circuit pattern formed on a mask surface is optically exposed on a photosensitive substrate by an exposure device. Transcribed. At this time, if foreign matter such as fine dust adheres to the mask, the shape of the foreign matter is transferred onto the photosensitive substrate during exposure, which causes a reduction in product yield. Therefore, the mask before the exposure step is sufficiently cleaned by the cleaning device to remove foreign matters.

In this cleaning apparatus, first, foreign substances adhering to the mask are removed by using a brush while a cleaning liquid made of pure water is flowing in the brush scrubbing tank. Next, the cleaning device cleans the brush residue and the like adhering to the mask surface during cleaning with a brush in the water washing tank by ultrasonic vibration in pure water.

As described above, the surface of the mask is cleaned by ultrasonic vibration in pure water in the water washing tank, and the circuit pattern on the mask is worn. However, since the pattern width on the mask is sufficiently thick and the amount of wear with respect to this thick pattern width is small, it has not been a big problem for the semiconductor integrated circuit to be manufactured. Further, there is no method for quantitatively measuring the amount of wear of the circuit pattern, and the amount of wear of the circuit pattern after cleaning has not been detected at present.

[0005]

By the way, in the above-mentioned mask, the circuit pattern on the mask has been miniaturized in recent years with the improvement of the integration degree of semiconductor elements. In a mask on which a circuit pattern of such a state-of-the-art minute line width rule (pattern width on the mask surface is 2 [μm]) is formed, the abrasion amount of the circuit pattern generated by one cleaning of the mask by the cleaning device is It is larger than the pattern width. For this reason, when the mask is transferred onto the wafer in the state where the circuit pattern is worn, there is a problem in that the manufactured semiconductor integrated circuit suffers disconnection, short circuit, and other defects.

Therefore, in order to solve the above-mentioned problems, it is necessary to inspect the circuit pattern on the mask for wear after cleaning the mask on which the circuit pattern having such a minute line width rule is formed. However, it takes a lot of time to inspect the mask for wear every time after cleaning.
Until the inspection is completed, there is a problem that the product cannot be manufactured and the throughput is lowered.

The present invention has been made in consideration of the above points, and provides a wear inspection mask and a circuit pattern wear inspection method capable of inspecting the wear of a circuit pattern formed on a mask with a simple structure in a short time. It is a proposal.

[0008]

In order to solve such a problem, in the present invention, a mask used for optically transferring a circuit pattern onto a photosensitive substrate by an exposure device has the same surface as the surface on which the circuit pattern is formed. A test pattern for wear test, which has the same pattern width and the same direction as the narrowest pattern width of the circuit pattern, is provided at a predetermined position inside the alignment mark on the surface.

On the same surface as the surface on which the circuit pattern is formed, a wear inspection test pattern is formed at a predetermined position on the inner side of the alignment mark in the same direction and with the same pattern width as the narrowest pattern width of the circuit pattern. The inspection pattern of the abrasion inspection mask is irradiated with a light beam, the scattered light generated according to the abrasion of the inspection pattern is received, the abrasion of the inspection pattern is inspected based on the received scattered light, and the abrasion of the inspection pattern By judging as the wear of the circuit pattern, the wear of the circuit pattern can be inspected in a short time.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the overall structure of a circuit pattern wear inspection system 1. The circuit pattern wear inspection system 1 includes a mask cleaning unit 2, a control unit 3 for controlling the mask cleaning unit 2, a foreign substance remaining on a cleaned mask, and a circuit for inspecting the wear of a circuit pattern by a laser scattering method. The pattern wear inspection unit 4 includes a determination unit 5 that determines with a microscope whether foreign matter is present on the inspected mask or whether the circuit pattern is worn.

In this circuit pattern wear inspection system 1, the mask cleaning unit 2 is controlled by the control unit 3, and while the cleaning liquid is flowing in the brush scrubbing chamber, the mask surface is cleaned by the brush to remove foreign matters. To do. After that, the mask cleaning unit 2 cleans the brush residue and the like adhering to the mask surface during cleaning with the brush in the water washing tank by ultrasonic vibration in pure water.

Subsequently, the mask cleaning section 2 is designed to dry the water droplets adhering to the mask surface in the steam drying tank by utilizing vaporization heat of alcohol such as isopropyl alcohol to send the mask to the circuit pattern wear inspection section 4. ing. In the circuit pattern wear inspection section 4, the entire surface of the mask 10 cleaned by the mask cleaning section 2 is irradiated with laser light, and reflected light is received by the light receiving surface of the photoelectric conversion element.

FIG. 2 shows the structure of the mask 10 in which the circuit pattern wear inspection section 4 is additionally provided with a chrome pattern for wear inspection for inspecting the wear of the circuit pattern. The mask 10 is provided with a square-shaped exposure area 11 in the central portion, and a skewed area 12 of a predetermined width is provided at a position separated from each side of the exposure area 11 by a predetermined distance.

In the area 12A of the oblique area 12, a "+"-shaped alignment mark 1 for alignment is formed in the center.
3 are provided. In addition, in the area 12B of the skewed area 12, a "-" shaped alignment mark 14 for alignment is provided. Further, a "-" shaped alignment mark 15 for alignment is also provided in the region 12C.

Further, on the mask 10, a chrome pattern 16 for wear inspection is provided at a predetermined position outside the exposure area 11 and inside the area 12A with the narrowest pattern width of the circuit pattern (not shown). They are provided with the same pattern width (2 [μm]). As a result, in the circuit pattern wear inspection system 1, it is possible to determine the wear of the chrome pattern 16 as the wear of the circuit pattern and determine whether the mask 10 is used or not.

As shown in FIG. 3, in the chrome pattern 16, the pattern 16A is formed in a cross shape, and patterns 16B and 1 are formed at each tip so as to be perpendicular to the tip.
6C are formed at positions separated by a predetermined distance so as to be sandwiched from both sides. Here, in the chrome pattern 16, the direction in which the cleaning liquid flows and the patterns 16B and 16C are perpendicular (or parallel).
And the pattern 16A is formed to be parallel (or vertical). As a result, the circuit pattern wear inspection unit 4 can easily detect the wear of the tip portion of the pattern 16A and the edges of the patterns 16B and 16C when the chrome pattern 16 is worn.

As shown in FIG. 4, when the chrome pattern 16 is not worn in the circuit pattern wear inspection section 4, the laser beam applied to the mask 10 is specularly reflected by the chrome pattern 16 and the specularly reflected light flux is reflected. A plurality of photoelectric conversion elements 2
The photoelectric conversion elements 22 to 24 of 1 to 25 receive light to detect that they are not worn. Accordingly, the circuit pattern wear inspection system 1 can determine that the chrome pattern 16 of the mask 10 is not worn, and thus can infer that the circuit pattern is not worn.

However, as shown in FIG. 5, in the circuit pattern wear inspection section 4, when the edge of the chrome pattern 16 is worn, the laser beam applied to the mask 10 causes the rounded edge portion of the chrome pattern 16. The photoelectric conversion elements 21, 22 and the photoelectric conversion elements 24, 25 receive scattered light generated by diffused reflection by the sensor, thereby detecting wear. Accordingly, the circuit pattern wear inspection system 1 can determine that the chrome pattern 16 of the mask 10 is worn, and thus can estimate that the circuit pattern is worn.

Here, when foreign matter remains on the mask 10, the circuit pattern wear inspection section 4 receives scattered light generated by diffuse reflection of the laser beam applied to the foreign matter by the photoelectric conversion element. , In this case also chrome pattern 16
It will be judged as worn.

Next, in the judging section 5, when the judgment result of the circuit pattern wear inspecting section 4 is the position where the chrome pattern 16 is provided, the portion where the chrome pattern 16 is provided and its surroundings are confirmed by a microscope. In this case, the determination unit 5 determines whether the determination result of the circuit pattern wear inspection unit 4 is due to the remaining foreign matter or the wear of the chrome pattern 16. At this time, when the determination unit 5 determines that the determination result of the circuit pattern wear inspection unit 4 is the wear of the chrome pattern 16, the circuit pattern wear inspection system 1 uses the mask 1
It is decided to stop using 0. In addition, when the determination unit 5 determines that the determination result of the circuit pattern wear inspection unit 4 is that the foreign matter remains, the circuit pattern wear inspection system 1 determines to use the mask 10 and performs cleaning again. There is.

With the above configuration, the processing procedure when the circuit pattern abrasion inspection system 1 inspects the abrasion of the circuit pattern of the mask 10 will be described with reference to the flow chart shown in FIG. The circuit pattern wear inspection system 1 enters from the start step of the processing procedure RT1 and moves to step SP1.

In step SP1, the circuit pattern wear inspection system 1 cleans the mask 10 over the entire surface in the mask cleaning section 2 and moves to step SP2. Step SP
In 2, the circuit pattern abrasion inspection system 1 inspects the entire surface of the cleaned mask 10 by the laser scattering type circuit pattern abrasion inspection unit 4, and moves to step SP3.

Subsequently, in step SP3, the circuit pattern wear inspection system 1 obtains a positive result when the detection result of the inspection unit 4 is neither residual foreign matter on the cleaned mask 10 nor abrasion of the chromium pattern. A negative result is obtained when either the foreign matter remains on the mask 10 or the chromium pattern is worn. If the circuit pattern wear inspection system 1 obtains a positive result (OK), it is determined that there is no abnormality, the process proceeds to step SP4, the use of the mask 10 is decided, and the operation procedure RT1 is ended. If the circuit pattern wear inspection system 1 obtains a negative result (NG), the process proceeds to step SP5.

In step SP5, the circuit pattern wear inspection system 1 investigates which position on the mask 10 the detection result of the circuit pattern wear inspection part 4 is, and moves to step SP6. At step SP6,
The circuit pattern wear inspection system 1 determines whether or not the detection result is at a location where the wear inspection chrome pattern 16 is provided.

If a negative result is obtained here, the circuit pattern wear inspection system 1 determines the chromium pattern 16 on the mask 10.
It is determined that the foreign matter is present at a place other than the place where is provided, and the process returns to step SP1 and the mask 10 is washed again. If a positive result is obtained at step SP6, the circuit pattern wear inspection system 1 will go to step SP7.
Move on to

In step SP7, the circuit pattern wear inspection system 1 confirms the place where the chrome pattern 16 is provided with a microscope and moves to step SP8. In step SP8, circuit pattern wear inspection system 1
Determines whether the chrome pattern 16 is worn.

If a negative result is obtained here, the circuit pattern wear inspection system 1 judges that the detection result is not the wear of the chrome pattern 16 but the remaining foreign matter, and this mask 1
0 is decided, and the procedure moves to step SP4 to execute the processing procedure R.
Terminate T1.

If a positive result is obtained in step SP8, the circuit pattern wear inspection system 1 determines that the chrome pattern 16 is worn, and proceeds to step SP9. In step SP9, the circuit pattern wear inspection system 1 estimates that the circuit pattern is worn because the chrome pattern 16 is worn and the mask 10 is worn.
Decide to stop using.

With the above structure, the circuit pattern wear inspection system 1 irradiates the mask 10 provided with the chrome pattern 16 for wear inspection with laser light, and based on the reflected light reflected by this chrome pattern 16, the circuit pattern is inspected. By detecting the wear of the chrome pattern 16, the wear of the chrome pattern 16 can be estimated as the wear of the circuit pattern formed on the mask 10. Thus, the circuit pattern wear inspection system 1 can inspect the wear of the circuit pattern on the mask 10 in a short time by inspecting the wear of the chrome pattern 16.

In the above embodiment, the chrome pattern 16 is located inside the oblique area 12 and in the exposure area 11.
Although the case where it is provided at a position on the outer side is described, the present invention is not limited to this, and the oblique region 1 on the mask 10 is not limited to this.
It may be provided in the exposure area 11 as long as it is inside 2. In this case, the chrome pattern 16 must be provided independently without contacting the circuit pattern.

In the above-described embodiment, the case where one chrome pattern 16 is provided on the mask 10 has been described, but the present invention is not limited to this, and the chrome pattern 16 may be provided inside the oblique region on the mask 10. For example, a plurality may be provided for easy inspection. In this case, the same effect as in the above-described embodiment can be obtained.

Further, in the above-described embodiment, the patterns 16B and 16 are parallel to (or perpendicular to) the direction in which the cleaning liquid flows during cleaning and the pattern 16A of the chromium pattern 16.
The case where C is formed to be vertical (or parallel) has been described, but the present invention is not limited to this, and may be formed in various directions depending on the direction in which the cleaning liquid flows and the cleaning method.

Further, in the above-described embodiment, the case where the chrome pattern 16 is formed in a cross shape has been described, but the present invention is not limited to this, and various shapes may be used if the edge portion can be easily recognized. good.

Further, in the above-mentioned embodiment, the case where the pattern width of the chrome pattern 16 is set to 2 [μm] has been described, but the present invention is not limited to this, and the chrome pattern corresponding to the narrowest pattern width of the circuit pattern. 16 may be formed.

Further, in the above embodiment, the mask 1
Although the case where the chrome pattern 16 is provided at 0 is described, the present invention is not limited to this, and the chrome pattern 1
Instead of providing 6, the alignment mark 13 provided in the oblique region 12 may be used as a chrome pattern for wear inspection. Also in this case, the circuit pattern wear inspection system 1 can obtain the same effect as that of the above-described embodiment by making the pattern width of the alignment mark 13 equal to the narrowest pattern width of the circuit pattern.

[0037]

As described above, according to the present invention, the narrowest pattern width of the circuit pattern is in the same direction and equal to the predetermined position of the inner portion of the alignment mark on the same surface as the surface on which the circuit pattern is formed. A test pattern of a wear test mask having a test pattern for wear test having a pattern width is irradiated with a light beam, and scattered light generated according to the wear of the test pattern is received, and the test is performed based on the received scattered light. By inspecting the wear of the pattern and determining the wear of the inspection pattern as the wear of the circuit pattern, it is possible to realize a wear inspection mask and a circuit pattern wear inspection method capable of inspecting the wear of the circuit pattern in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a circuit pattern wear inspection system according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the structure of a mask according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a chrome pattern according to an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a state of a chromium pattern which is not worn according to an embodiment of the present invention.

FIG. 5 is a schematic diagram showing a state of a worn chromium pattern according to an embodiment of the present invention.

FIG. 6 is a flowchart showing a processing procedure of the circuit pattern wear inspection system 1 according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Circuit pattern wear inspection system, 2 ... Mask cleaning unit, 3 ... Control unit, 4 ... Circuit pattern wear inspection unit,
5 ... Judgment part, 11 ... Exposure area, 12 ... Oblique area, 13, 14, 15 ... Alignment mark, 16 ...
... Chrome pattern, 21 to 25 ... Photoelectric conversion element.

Claims (4)

[Claims] 1. A mask used for optically transferring a circuit pattern onto a photosensitive substrate by an exposure device, wherein the mask is used at a predetermined position inside an alignment mark on the same surface as the surface on which the circuit pattern is formed. A wear inspection mask having a wear inspection inspection pattern having the same pattern width and the same direction as the narrowest pattern width of the circuit pattern. 2. The wear inspection mask according to claim 1, wherein the inspection pattern is formed in the same direction as the flowing direction of the cleaning liquid. 3. A test for wear test, which is in the same direction as and has the same pattern width as the narrowest pattern width of the circuit pattern at a predetermined position inside the alignment mark on the same surface as the surface on which the circuit pattern is formed. The inspection pattern of the abrasion inspection mask having a pattern is irradiated with a light beam, the scattered light generated according to the abrasion of the inspection pattern is received, and the abrasion of the inspection pattern is inspected based on the received scattered light, A circuit pattern wear inspection method, characterized in that the wear of an inspection pattern is judged as the wear of the circuit pattern. 4. The circuit pattern wear inspection method according to claim 3, wherein the inspection pattern is formed in the same direction as the flow direction of the cleaning liquid.