JPH07151691A - Apparatus and method for detecting dirt or defect of mask for exposure - Google Patents

Abstract

PURPOSE:To achieve efficiency of inspection, shortening of inspection time and malfunctioning as caused by noises generated at an end part of a light shielding pattern in the inspecting of dirts or surface irregularity defects on a mask for close exposure or a mask for exposure such as reticle mask. CONSTITUTION:A system is arranged to detect the scattered light 32 of a laser light 30 generated attributed to dirts 31 and surface irregularity defects by a scanning on a reticle mask 1 by the laser light 30 so that it is judged to be dirts and a system to let the light 33 released from a light source 3 reach an image sensor 4 through the reticle mask 1 so that a light shielding pattern 2 is recognized. Information from both the systems is compared to remove the dirts 31' and the surface irregularity defects on the light shielding pattern 2 to process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for detecting dust or surface irregularity defects on an exposure mask, and particularly to a transparent portion of the dust or surface irregularity defects on the exposure mask excluding the light-shielding pattern. TECHNICAL FIELD The present invention relates to an apparatus and method for detecting dust or surface irregularity defects existing in an automobile.

[0002]

2. Description of the Related Art A conventional apparatus for detecting dust or surface irregularity defects on an exposure mask has a dust or surface irregularity defect when an exposure mask such as a contact exposure mask or a reticle mask is irradiated with laser light. In this case, the fact that the laser light becomes scattered light has been used.

That is, the laser light was scanned over the entire surface of the exposure mask or in a designated area, and it was determined that there were dust or surface irregularity defects at the locations determined to be scattered light by the detectors attached to the four sides. Then, if a detector is installed on the irradiation side of laser light, dust or surface irregularity defects on the entire scanned area are detected, and if a detector is installed on the opposite side of the irradiation side of laser light, the exposure mask It was judged that dust on the transparent portion or surface irregularity defect was detected.

As another conventional device for detecting dust or surface irregularity defects on an exposure mask, an image sensor is used to pick up an image of an exposure mask without dust or surface irregularity defects, and the output signal from this image sensor is output. As a reference, the dust or the surface irregularity defect was detected based on the difference from the output signal from the exposure mask having the dust or the surface irregularity defect.

[0005]

However, in the method using the laser beam of the above-mentioned prior art, even when the detector is installed on either side of the laser beam irradiation side,
A light-shielding pattern formed by patterning a light-shielding film such as a chrome film causes the laser light to become scattered light at the end portion due to the step of the light-shielding film, which may be erroneously determined as an inconvenient dust or surface irregularity defect. It has a problem that it occurs.

On the other hand, the conventional method using the image sensor has a problem that it takes an enormous amount of time to deal with various kinds of exposure masks.

[0007]

A feature of the present invention is a dust detecting means for scanning a laser beam to discriminate dust or surface irregularities on an exposure mask such as a contact exposure mask or a reticle mask as scattered light. A device for detecting dust or surface irregularity defects of an exposure mask, which comprises pattern input means for taking in the light-shielding pattern of the exposure mask, and which makes it possible to remove dust or surface defects in the light-shielding pattern for processing. is there.

Another feature of the present invention is dust detection means for scanning a laser beam to discriminate dust or surface irregularities on an exposure mask such as a contact exposure mask or a reticle mask as scattered light; For exposure having pattern input means for taking in the light-shielding pattern of the mask, and comparison means for comparing the position information on the presence of dust or surface irregularity defect obtained by the dust detection means with the light-shielding pattern information by the pattern input means It is in a device that detects dust on the mask or surface irregularities.

Another feature of the present invention is that a light-shielding pattern of an exposure mask such as a contact exposure mask or a reticle mask is recognized and stored, and a laser beam is scanned to scatter dust or surface irregularities on the exposure mask. Another method is to detect dust or surface irregularity defects on the exposure mask, which is detected as light and removes dust or surface irregularity defects on the light-shielding pattern among the dust or surface irregularity defects on the exposure mask.

Here, the pattern input means in the pattern recognition and storage step is a light source located on one side of the exposure mask and light from the light source, for example, light used when performing an exposure process using this exposure mask. Same kind of UV light,
An image sensor located on the other side of the exposure mask for receiving light such as i-line and g-line through the exposure mask, and a pattern recognition unit for inputting a signal from the image sensor. it can.

Alternatively, the pattern input means in the pattern recognition storage step may be configured to have a pattern input section capable of inputting and storing graphic data of the light-shielding pattern of the preliminary exposure mask.

Further, the laser light can be scanned except for the entire portion of the light shielding pattern, or the laser light can be scanned except for a portion of the light shielding pattern.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. In the examples, only dust among the dust and surface irregularity defects will be described as a representative, but the same applies to the surface irregularity defect.

FIG. 1 is a diagram showing a first embodiment of the present invention. When inspecting the dust 31 on the reticle mask 1, the reticle mask 1 is installed below the light source 3 and the light 33 from the light source, for example, the same kind of ultraviolet light as the light used when performing the exposure process using this reticle mask. , I-line, g-line, etc. are applied to the entire surface of the reticle mask 1. Since the light blocking pattern 2 of the reticle mask 1 does not pass the light 33,
The image sensor 4 located below the reticle mask 1 senses a portion other than the light-shielding pattern 2, that is, the glass transparent portion of the reticle mask 1. The signal that senses this light is processed by the pattern recognition unit 10, and the light shielding pattern 2 is recognized and stored.

Next, the laser beam 30 emitted from the laser section 5 is applied to the entire surface of the reticle mask 1 or a designated area through the scan mirror 6 controlled by the laser scan controller 8.

Laser light 3 which has passed through this scan mirror 6
Dust 31 attached to the surface of reticle mask 1 produces scattered light 32. When the scattered light 32 is received by the light-receiving sensors 7 attached in each of the four directions, and when the dust detection controller 9 inputs a certain amount or more to all (four) light-receiving sensors 7, a determination process such as generation of scattered light is performed. To do.

The dust information generated by scattered dust from the dust detection controller 9 and the position data from the laser scan controller 8 are sent to the in-area dust detection unit 11 to identify the presence of dust 31 and its position. Then, the existence position information of this dust 31 and the light-shielding pattern information from the pattern recognition unit 10 are sent to the comparison unit 12, and by comparing them, the dust 31 'on the light-shielding pattern 2 and the dust 31' on the glass transparent portion. In distinction from ', the dust 31' on the light-shielding pattern 2 does not hinder the exposure work even if it is present, and is therefore deleted from dust recognition.

Further, by this, the scattered light generated due to the step at the end portion of the light shielding pattern 2 is also deleted, so that no false detection occurs.

Then, the result display section 13 displays the portion of the reticle mask 1 excluding the light-shielding pattern 2, that is, the dust 31 ″ on the glass transparent portion as the dust which is inconvenient during the exposure operation.

FIG. 2 is a diagram showing a second embodiment of the present invention.

In this embodiment, the light-shielding pattern 15 of the reticle mask 14 is input and stored in the pattern input unit 19 in advance based on its coordinate data and the like.

Next, as in the first embodiment, the laser unit 1
The reticle mask 14 is irradiated with the laser light 40 emitted from the laser beam 6 through the scan mirror 17 controlled by the laser scan controller 20, and the scattered light 42 by the dust 41 is received by the light receiving sensors 18 attached in four directions, respectively. The dust detection controller 21 performs a determination process such as generation of scattered light.

In the second embodiment, the pattern input section 1
Information from 9 is transferred to the comparison unit 23, and
It is also transferred to the laser scan controller 20 and the laser scanning range is limited to only the transparent glass surface excluding the light shielding pattern 15, or only the small area 15B except the large area 15A and the transparent glass surface in the light shielding pattern 15 are formed. Limit the range of laser scanning. FIG. 2 shows the latter case, that is, the laser scanning range is limited to the small area 15B in the transparent glass surface and the light shielding pattern 15.

The dust information generated by scattered dust from the dust detection controller 21 and the position data from the laser scan controller 20 are sent to the in-area dust detection unit 22,
Presence of the dust 41 in the scanned area 44, that is, the small area 15B of the light-shielding pattern 15 and the glass transparent portion and the position thereof are specified except for the non-scanned area 45 corresponding to the large-area area 15A of the light-shielding pattern 15.

The dust position information and the shading pattern information from the pattern input unit 19 are sent to the comparing unit 23, and by comparing the two, dust 41 on the scanned small area 15B of the shading pattern 15 is detected. The dust 41 'on the light-shielding pattern 15B is distinguished from the dust on the transparent portion, and the dust 41' on the light-shielding pattern 15B does not hinder the exposure work even if it is present. Only the upper dust 41 ″ is displayed on the result display unit 13 as being inconvenient dust during the exposure operation.

In the second embodiment, by limiting the laser scan range, especially in the case where the exposure range is small or the exposed portion is deviated, the dust inspection is performed only on the necessary portion to shorten the time. There is an advantage that can be measured.

The devices of the first and second embodiments are
It is integrated with the exposure device, and by the transfer of the exposure mask, the transfer of dust is carried out without vibration or dust generation without new adhesion.

[0028]

As described above, the present invention recognizes or registers a light-shielding pattern in an apparatus and method for inspecting dust or surface irregularity defects on an exposure mask such as a contact exposure mask or a reticle mask. The dust or surface irregularity defect detected on the light-shielding pattern is deleted and processed.

Further, erroneous detection due to noise generated at the end surface of the light shielding pattern is reduced.

Further, the detection time can be shortened by implementing the sequence as in the second embodiment.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a second embodiment of the present invention.

[Explanation of symbols]

 1,14 Reticle mask 2 Light-shielding pattern 3 Light source 4 Image sensor 5,16 Laser unit 6,17 Scan mirror 7,18 Light receiving sensor 8,20 Laser scan controller 9,21 Dust detection controller 10 Pattern recognition unit 11,22 Dust in area Detection unit 12,23 Comparison unit 13,24 Result display unit 15 Light-shielding pattern 15A Large-area region of light-shielding pattern 15B Small-area region of light-shielding pattern 19 Pattern input unit 30,40 Laser light 31,41 Dust 31 ', 41' Light-shielding pattern Dust on top 31 '', 41 '' Dust on glass transparent part 32, 42 Scattered light 33 Light 44 Scanned area 45 Non-scanned area

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G06T 7/00 1/00 H01L 21/027 9061-5L G06F 15/70 455 B 7352-4M H01L 21 / 30 502 V

Claims (10)

[Claims] 1. A dust detecting means for scanning a laser beam to discriminate dust or surface irregularity defects on an exposure mask such as a contact exposure mask or a reticle mask as scattered light, and a light-shielding pattern of the exposure mask. An apparatus for detecting dust or defects in an exposure mask, comprising: a pattern input unit for inserting the pattern; and enabling removal and treatment of dust or surface defects in the light-shielding pattern. 2. A dust detecting means for scanning a laser beam to discriminate dust or surface irregularities on an exposure mask such as a contact exposure mask or a reticle mask as scattered light, and a light shielding pattern of the exposure mask. Pattern input means for inserting, and a comparison means for comparing the position information where the dust or surface unevenness defect obtained by the dust detection means and the light shielding pattern information by the pattern input means,
An apparatus for detecting dust or defects on an exposure mask, wherein dust or surface irregularities on the light-shielding pattern among the dust or irregularities on the exposure mask can be deleted and processed. 3. The pattern input means is a light source located on one side of the exposure mask, and an image sensor located on the other side of the exposure mask, which receives light from the light source through the exposure mask. And a pattern recognition unit for inputting a signal from the image sensor.
An apparatus for detecting dust or defects on the exposure mask according to the item 1. 4. The dust of the exposure mask according to claim 3, wherein the light from the light source is the same kind of light as the light used when performing the exposure step using the exposure mask. A device that detects defects. 5. The pattern input means comprises a pattern input section capable of previously inputting and storing graphic data of a light-shielding pattern of the exposure mask. An apparatus for detecting dust or a defect of the exposure mask according to claim 1 or 2. 6. The apparatus for detecting dust or defects on an exposure mask according to claim 5, further comprising means for controlling a scanning range of the laser light according to a signal from the pattern input means. 7. A result display unit for displaying only dust or surface irregularity defects existing in a transparent portion of the exposure mask except the light-shielding pattern, according to information from the comparison unit. An apparatus for detecting dust or defects of the exposure mask described. 8. A light-shielding pattern of an exposure mask such as a contact exposure mask or a reticle mask is recognized and stored, and a laser beam is scanned to detect dust or surface irregularities on the exposure mask as scattered light. A method for detecting dust or defects in an exposure mask, which comprises removing dust or surface irregularities on the light-shielding pattern from among dust or surface irregularities on the exposure mask. 9. The method for detecting dust or defects on the exposure mask according to claim 8, wherein the laser light is scanned except for the entire portion of the light shielding pattern. 10. The method for detecting dust or defects on an exposure mask according to claim 8, wherein the laser light is scanned except for a part of the light shielding pattern.