JPH0545863A - Defect inspecting device for photomask - Google Patents

Abstract

PURPOSE:To automate the defect inspection of a photomask. CONSTITUTION:The defect inspecting device 11 which supplies the inspected reticule 1 to a stepper 10 is provided with a stocker 13 which houses plural sheets of the reticules 1, a deciding section 15 which decides the feasibility of the use of the reticule 1 or not in accordance with the result of the foreign matter inspection and a transfer device 16 which transfers the reticules 1 between the stocker 13, the foreign matter inspecting device 14 and the stepper 10. The reticule 1 is stocked in the stocker 13. The reticule 1 is automatically transferred by a transfer device 14 to the foreign matter inspecting device 14. The foreign matter of the reticule 1 is automatically detected and the feasibility of the use of the reticule or not is automatically decided in accordance with this detection data and, therefore, the need for a human interposing is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask defect inspection apparatus, and more particularly to a technique for supplying an inspected photomask with an inspected photomask.
That. ), Which is effective for use in the lithography processing step in the manufacturing process.

[0002]

2. Description of the Related Art With the progress of higher integration of ICs and finer patterns, the line width of circuit patterns has become 1 μm or less. As the line width becomes finer, a reduction projection exposure apparatus (hereinafter referred to as a stepper) is often used in a lithography processing step in which a circuit pattern is transferred onto a semiconductor wafer (hereinafter referred to as a wafer). There is. When this stepper is used, a magnified photomask, that is, a reticle, in which the pattern to be transferred onto the wafer is magnified 5 to 10 times, is used.

Then, the enlarged pattern of the reticle is reduced and projected and exposed on the wafer by the stepper, and the same pattern is repeatedly transferred. Therefore, so-called white defects (pattern disconnection defects, etc.) and black defects (pattern contact, protrusions, etc.) in the enlarged pattern of the reticle, and further foreign matter attached to the reticle (hereinafter referred to as defects including foreign matter). If there are defects, these defects will be repeatedly transferred to the wafer. When defects are repeatedly transferred to the wafer in this manner, so-called all-pellet defects occur, and productivity is significantly reduced.

Therefore, in the lithographic processing step in the IC manufacturing process, a defect inspection is performed on the reticle before the transfer by the stepper is executed.
Inspected reticles are supplied to steppers. That is, by supplying the stepper with a reticle that is determined to be usable by the defect inspection, all pellet defects are prevented from occurring.

As an example in which the photomask inspection technique is described, "Electronic Materials 1988" issued by Kogyo Kenkyukai Co., Ltd.
Issue, December issue, issued on December 13, 1988, P15
9 to P167.

[0006]

However, in the conventional photomask defect inspection apparatus, an artificial judgment may be involved in the judgment as to whether or not the reticle can be used, so that time is wasted in the judgment. However, there is a problem in that there are variations in judgment, which may result in erroneous judgments and irrational judgments. In addition, there is a problem that when a reticle is supplied or stored, dust is emitted from a person and foreign matter may adhere to the reticle or the pattern may be damaged.

An object of the present invention is to provide a photomask defect inspection apparatus capable of automatically performing a defect inspection of a photomask while eliminating human intervention and automatically supplying an inspected photomask to an exposure apparatus. To provide.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0009]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, a photomask defect inspection apparatus for supplying an inspected photomask to an exposure apparatus, and a storage section for storing a plurality of photomasks, and an inspection execution section for executing a defect inspection of the photomask and detecting a defect. A determination unit that determines whether or not the photomask can be used based on the inspection result of the inspection execution unit; and a transfer device that transfers the photomask between the storage unit, the inspection execution unit, and the exposure apparatus. And

[0011]

In the above means, the photomask stored in the storage portion is taken out by the transfer device and automatically transferred to the inspection execution portion. The photomask transferred to the inspection execution unit is subjected to defect inspection, and the defect is detected. The data relating to the detected defect is transmitted to the determination unit, and the determination unit determines whether the inspected photomask is usable based on this data. The photomask determined to be usable is directly transferred to the exposure device by the transfer device. Alternatively, depending on the circumstances of the exposure apparatus, it is once returned to a predetermined position in the storage unit and then transferred to the exposure apparatus.

In this way, according to the above-mentioned means,
Since the inspected photomask is automatically supplied to the exposure apparatus without human intervention, it is possible to reliably prevent all pellet failures from occurring.

[0013]

1 is a block diagram showing a reticle defect inspection apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing a foreign matter inspection apparatus used therein, and FIG. 3 is a drift correction apparatus thereof. 6 is a schematic perspective view, FIG. 4 is a plan view showing a reticle, FIG. 5 is a perspective view showing a reticle cassette, and FIG.
FIG. 7 is an explanatory diagram for explaining the operation of the foreign matter inspection device, FIG. 7 is an explanatory diagram for explaining the determination operation, and FIG. 8 is a flow chart showing the overall flow.

In this embodiment, a photomask defect inspection apparatus 11 according to the present invention is a stepper 1 as an exposure apparatus.
It is configured to automatically configure the reticle 1 as a photomask that has been subjected to defect inspection to 0. In the reticle 1 which is the object to be inspected, the pattern 3 to be transferred is formed on the blank 2 made of quartz glass by using chrome or the like, and the chrome pattern 3 is formed by an appropriate means such as an electron beam drawing device. It is formed to be 5 to 10 times larger than an actual circuit pattern (not shown) formed on a wafer (not shown). Further, the reticle 1 has a plurality of target marks 4 arranged at predetermined positions and formed in the same manner as the chrome pattern 3. In FIG. 4, 5 is a foreign substance attached to the chrome pattern 3, and 6 is a foreign substance attached to the blank 2. The reticle 1 is accommodated in a reticle cassette 9 and transferred as shown in FIG. 5 in order to prevent contamination.

In the present embodiment, the photomask defect inspection apparatus 11 executes a reticle stocker 13 as a photomask storage section and a foreign matter inspection as a reticle defect inspection, and detects a foreign matter as a defect. An inspection device 14, and a foreign matter management system 15 that also serves as a determination unit that determines whether or not the reticle can be used based on the inspection result of the foreign matter inspection device 14 and manages the data.
A transfer device 16 for transferring the reticle 1 stored in the cassette 9 and a controller 17 that is connected to these devices by a LAN line and controls them are provided. Further, the controller 17 is connected to a central processing unit (hereinafter referred to as CPU) 12.

Next, the reticle stocker 13 for explaining each component is constructed so that a plurality of the reticle 1 can be stored in the cassette 9 in a state where the reticle 1 is stored in the cassette 9. In the state where the reticle 1 is stored in the stocker 13, the reticle 1 before or after the inspection is arranged and stored according to the type of the semiconductor device to be manufactured and the process used, and the storage position is the controller 17 or. It is stored in a storage unit such as the CPU 12.

As shown in FIG. 2, the foreign substance inspection device 14 as an inspection execution device has a reticle 1 which is an object to be inspected.
First, the oblique illumination device 20 for obliquely irradiating the laser light as the inspection illumination light, the condenser lens 21 for condensing the light from the reticle 1, and the first half mirror 25 for condensing the light.
An imaging lens 22 for forming an image on each of the detector 23A and the second detector 23B, a light-shielding element 24 arranged in front of the first detector 23B and including a spatial filter or an analyzer, and the first detector 23A. And the first signal processing circuit 30A and the second signal processing circuit 30B, which are connected to the second detector 23B, and both processing circuits 30A and 30B.
0B, a first quantizer circuit 31A and a second quantizer circuit 31B, an arithmetic circuit 32 connected to both quantizer circuits 31A and 31B, and an arithmetic circuit 3.
2 is connected to the coordinate storage unit 33, and this storage unit 33
And a comparison circuit 34 connected to.

The foreign matter inspection device 14 is provided below the lower illuminating device 26 for irradiating the reticle 1 with laser light as inspection illuminating light from directly below, and optically behind the lower illuminating device 26 on the optical axis. The phase element 27 and the second condenser lens 28 that condenses the light transmitted through the phase element 27 and irradiates the reticle 1 with the condensed light.

Next, a method for inspecting foreign matter in the foreign matter inspecting apparatus 14 having the above-mentioned structure will be described. First, the reticle 1 is irradiated with laser as inspection illumination light from the oblique illumination device 20. By this illumination, scattered light is generated from the foreign matters 5 and 6 as defects on the reticle 1 and the chrome pattern 3, and the scattered light is condensed by the condenser lens 21 and also passes through the imaging lens 22 to the first detector. An image is formed on 23A. The pellicle is omitted in FIG.

At this time, since the scattered light from the chrome pattern 3 has regularity, the light shielding element 24, which is a spatial filter or an analyzer, provided on the Fourier transform surface of the pattern surface of the reticle 1 causes the light to escape from the chrome pattern 3. The scattered light is blocked. On the other hand, since the scattered light from the foreign matters 5 and 6 is irregular and passes through the spatial filter or the analyzer to be imaged on the first detector 23A, only the foreign matters 5 and 6 can be detected. Become.

The signal detected by the first detector 23A is processed by the arithmetic circuit 32 via the first signal processing circuit 30A and the first quantization circuit 31A.

[0022] Here, the signal detected by the first detector 23A during the look like FIG. 6 (a), the signal V ₆ from a particle 5,6, the signal V ₃ from the chromium pattern 3 By setting the threshold value (V _th ) at, it is possible to detect only the signal V ₆ from the foreign matters 5 and ₆ .

On the other hand, regarding the flat defects such as the chrome pattern 3, the white defect and the black defect, the illumination light from the lower illuminating device 26 below the reticle 1 is passed through the phase element 27 to the condenser lens 2.
It is detected by being condensed at 8 and irradiated on the reticle 1. That is, the illumination light from below that has passed through the reticle 1 is condensed by the condenser lens 21, and the imaging lens 2
2 forms an image on the second detector 23B. Here, the separation into the first detector 23A and the second detector 23B is performed by the half mirror 25. The detected signal processing is executed by the second signal processing circuit 30B, the second quantization circuit 31B and the arithmetic circuit 32.

Next, the foreign substances 5 and 6 are chrome patterns 3
A method of determining whether the surface is present on the surface or on the other surface of the glass blank 2 will be described.

A reticle 1 is provided with an oblique illumination device 2 from the upper surface thereof.
The illumination light of 0 and the illumination light of the lower illumination device 26 that illuminates from the lower surface thereof are simultaneously emitted. At this time, depending on the oblique illumination, the foreign matter 6 attached on the surface of the glass blank 2 and the foreign matter 5 attached on the surface of the chrome pattern 3
Is the first detector 2 as shown in FIG. 6 (b).
Both are detected by 3A.

On the other hand, when the illumination light illuminated from below the surface of the reticle 1 is examined, the foreign matter 6 adhering to the surface of the glass blank 2 is raised, so that the second detector as shown in FIG. The signal V ₆ is detected at 23B. On the other hand, since the foreign matter 5 attached on the surface of the chrome pattern 3 is shielded from light by the chrome pattern 3,
As shown in (c), the signal V ₅ is not detected by the second detector 23B. Therefore, the first detector 23
By effectively dividing the detection signals of A and the second detector 23B, it is possible to detect only the foreign matter 5 attached on the surface of the chrome pattern 3.

The coordinates of the foreign matter 5 on the surface of the chrome pattern 3 thus detected are stored in the coordinate storage unit 33. In this way, the position coordinates of the foreign matter signals V ₅ and V ₆ detected in FIG. 6B and the signal V ₅ from the foreign matter 5 on the surface of the chromium pattern 3 detected in FIG. 6C are obtained.
6 is compared with the position coordinates of FIG.
As shown in (d), when they do not match, the signal V ₆ is for the foreign matter 6 on the surface of the glass blank 2,
Will be certified.

Next, the operation of recognizing and recording the positions of the foreign matters 5 and 6 on the reticle 1 as coordinate values from the reference mark position will be described.

For example, as shown in FIG. 4, the coordinate value of the foreign matter 5 on the reticle 1 is used by the alignment mark 4 of the reticle 1 as the origin of the coordinates, and the distances X and Y from the alignment mark 4 are used. Is recognized as the coordinate value. When the reticle 1 is used and the chrome pattern 3 of the reticle 1 is transferred onto the wafer, it is determined on the reticle 1 which position on the wafer the foreign substance 5 specified on the reticle 1 is located. By converting the coordinate value of the foreign matter 5 specified in step 2 into the coordinate value on the wafer, the foreign matter analysis of the transfer position on the wafer can be easily performed.

An illumination laser light drift correction device 41 is added to the foreign matter inspection device 14, and this drift correction device 41 improves the irradiation position accuracy of the laser light illuminating the reticle 1 to detect detected foreign substances. Reproducibility is improved. The drift correction device 41 will be described below with reference to FIG.

As shown in FIG. 3, the drift correction device 41 is provided with a carbano mirror 42, and the laser light 40 is scanned by the carbano mirror 42. A pair of left and right photosensors 43, 43 are provided on the left and right sides of the reflection side of the carbano mirror 42.
Are installed respectively, and both photosensors 43, 43 are connected to a controller 44. The controller 44 is connected to a driving device 45 of the galvano mirror 42, and by controlling the driving device 45, the swing angle of the galvano mirror 42 is controlled.

Next, the operation of the drift correction device 41 will be described.

The laser light 40 is used as irradiation light for detecting foreign matter on the reticle 1. The laser beam 40 is scanned over the entire surface of the reticle 1 by the galvanometer mirror 42, but a so-called drift occurs in which the irradiation position shifts due to a change with time. Therefore, even when the same reticle 1 is inspected, the coordinate values of the foreign matters 5 and 6 detected at the first time and the second time may change. in this case,
Since the position of the first foreign substance and the position of the second foreign substance do not match, the foreign substance whose position is displaced is determined to be the increased foreign substance when the automatic pass / fail judgment described below is performed. For this reason,
Even a reticle 1 that passes will be erroneously determined as a failure.

In order to prevent such a situation, drift correction is executed. That is, as shown in FIG. 3, the laser light 40 is reflected by the galvanometer mirror 42 on the reticle 1.
The entire surface is scanned. At this time, the laser light 40
Left and right sensors 4 provided at both ends of the scanning area 46 of
When the laser beam 40 is detected or non-detected by any one of 3 and 43, the controller 44 issues a correction command to the galvanometer mirror 42, and the irradiation position is corrected.

In the present embodiment, as described above, the determination unit 15 as a component connected to the foreign matter inspection device 14.
Is substantially configured by the arithmetic circuit 32, the coordinate storage unit 33, and the comparison circuit 34. That is, since the foreign matter 5 attached on the surface of the chrome pattern 3 is not transferred onto the wafer even when exposed, it is determined that the reticle 1 having such foreign matter 5 can be used. On the other hand, the foreign matter 6 attached on the surface of the glass blank 2
When exposed, it is determined that the reticle 1 having such a foreign substance 6 as a defect cannot be used because it is transferred onto the wafer.

Next, an automatic acceptance / rejection determination method in the determination unit / foreign matter management system 15 based on the inspection result in the foreign material inspection device 14 will be described with reference to FIG.

FIGS. 7A, 7B, and 7C show the chromium pattern 3 on the reticle 1 and the detected two kinds of foreign matters 5 and 6, respectively. FIG. 7 (d),
(E) and (f) show foreign matter maps 1A, 1B, and 1C corresponding to FIGS. 7 (a), (b), and (c), respectively.

First, as shown in FIG. 7 (b),
Assuming that the initial foreign matter 5 on the surface of the reticle 1 is measured at the time of receiving the reticle 1 into the semiconductor device manufacturing factory, as shown in FIG. The foreign matter map 1B is recorded in the storage unit 33.

Next, the same reticle 1 is inspected for foreign matter, as described above, before being supplied to the stepper 10. If a foreign substance 6 newly attached to the surface of the glass blank 2 is detected as shown in FIG. 7A by this foreign substance inspection, as shown in FIG. Two initial foreign matters 5 and a newly increased foreign matter 6 are recorded in the second foreign matter map 1A for this reticle 1.

The position coordinates and the foreign matter size of the foreign matters 5 and 6 recorded in the foreign matter maps 1A and 1B of FIGS. 7D and 7E are subtracted by the comparison unit 34. As a result, as shown in FIG. 7C, since the common initial foreign matter 5 is removed, only the newly increased foreign matter 6 is extracted. That is, the first foreign matter map 1B is subtracted from the second foreign matter map 1A,
As shown in (f), the third foreign matter map 1C is obtained.

In this way, when the newly increased foreign matter 6 is extracted, it is rejected, and when there is no increased foreign matter 6, the foreign matter management system 15 also serves as the foreign matter management system 15 which also serves as the determination unit. Determine automatically.

Further, as described above, even if the foreign matter 5 attached on the surface of the chrome pattern 3 of the reticle 1 increases,
If it is on the surface of the chrome pattern 3, it will not be transferred to the product when exposed, and therefore it will be treated as a harmless foreign substance and passed.

However, the foreign matter 6 other than the chrome pattern 3
When it is exposed, it is transferred to the product, so it becomes a common defect of the whole product and creates a defect. Therefore, in this case, it is processed so as to be rejected as a harmful foreign substance. This makes it possible to determine whether the detected foreign matter is harmful or harmless by managing the coordinates of the foreign matter.

At the same time, depending on the size of the detected foreign matter, a criterion is also provided such that a foreign matter larger than a certain size is a harmful foreign matter and a small foreign matter below a certain size is a harmless foreign body.

The transfer device 16 is composed of a robot or the like, and in response to a command from the controller 17, the stocker 13
The reticle cassette 9 is taken out from the foreign matter inspection device 14
The reticle 1 that has been transferred to the
It is configured so as to be stored in and transferred to the stepper 10 or returned to the stocker 13.

The controller 17 is composed of a microcomputer, a memory and the like, and by collating the data regarding the product type and process from the CPU 12 with the data preset in the table, the reticle 1 to be inspected from now on. Along with the selection, the inspection conditions and the like necessary for inspecting the reticle 1 are selected and instructed to the stocker 13, the transfer device 16, and the foreign substance inspection device 14. For example, the inspection conditions for inspecting the reticle 1 include conditions for detection sensitivity, conditions of the reticle shape and inspection location, height and width conditions of the pellicle frame, and detection method,
There is.

The CPU 12 is constructed by a computer, a storage device and the like, and is configured to automatically execute production management, data management and production control in a semiconductor device manufacturing factory. Then, the CPU 12 monitors the processing status and reasonably transmits a predetermined command to the controller 17 in order to rationally manage or control the lithography processing step.

Next, the overall operation of the photomask defect inspection apparatus according to this embodiment will be described with reference to FIG.

In accordance with an instruction from the CPU 12 regarding the reticle type, process, etc., the controller 17 issues a transfer instruction for the reticle 1 to the transfer device 16. In response to this, the transfer device 16 ejects the designated reticle 1 from the reticle stocker 13 and conveys it to the foreign matter inspection device 14.

When the reticle 1 is set in the foreign matter inspection device 14, a reticle acceptance completion signal is transferred to the foreign matter management system 15 which also serves as a determination unit. Upon completion of acceptance, the foreign substance inspection device 14 receives the instruction of the inspection condition from the foreign substance management system 15 and executes the inspection.

After the inspection is completed, the inspection result is transferred to the foreign matter management system 15, and the foreign matter inspection apparatus 14 has an unload instruction.

The reticle 1 which has passed the inspection result after being processed by the foreign matter management system 15 is the controller 1
In accordance with the transportation instruction from the stepper 1,
The reticle 1 is transported to 0 and set as an inspected reticle 1.

Then, the stepper 10 executes the exposure process using the reticle 1 that has been inspected. After the exposure process is completed, the reticle 1 is transported to the reticle stocker 13 by the transfer device 16 and stored in a predetermined place.

Incidentally, the reticle 1 which has failed as a result of the inspection is appropriately returned to the stocker 13 by the transfer device 16. At this time, according to a command from the controller 17, the rejected reticle 1 is stored in a predetermined place in the stocker 13. Further, in order to deal with an unexpected accident such as a case where the stepper 10 is out of order, the reticle 1 that has passed the stocker 1
It may be temporarily returned to 3. In the stocker 13, the accepted reticle 1 and the rejected reticle 1 are sorted and stored. In some cases, the reticle 1 that has passed the inspection is stored in the stocker 13 by executing the inspection in advance by using the idle time, and the reticle 1 that is inspected in advance is directly transferred to the stepper 10 by the transfer device 16. ..

According to the above embodiment, the following effects can be obtained. The reticle 1 which is an enlarged mask is stored in the stocker 13, the reticle 1 designated by the controller 17 is automatically transferred to the foreign substance inspection device 14 by the transfer device 16, and the foreign substance inspection device 14 also detects the foreign substance on the reticle 1. Is automatically detected, and whether or not the reticle 1 can be used is automatically determined based on the detected data, so that human intervention can be eliminated.

By eliminating human intervention, cleaning in the exposure process can be further promoted, and irrational judgments such as judgment errors and fluctuations in judgments can be eliminated. Can be reliably prevented, the yield can be improved, and the product quality and reliability can be improved.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the defect inspection execution unit is not limited to be configured to perform only the foreign substance inspection, but may be configured to be able to inspect other defects such as white defects and black defects of the chrome pattern itself. ..

The controller is not limited to being connected to the CPU, but may be configured to exclusively input or store external data.

In the above description, the case where the invention made by the present inventor is mainly applied to the reticle defect inspection technique which is the background field of application has been described.
The present invention is not limited to this, and can be applied to general defect inspection techniques for photomasks such as 1: 1 photomask defect inspection techniques.

[0061]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

The reticle, which is an enlarged mask, is stored in the stocker, the reticle designated by the controller is automatically transferred to the defect inspection device by the transfer device, and the defect of the reticle is automatically detected by the defect inspection device. At the same time, whether or not the reticle can be used is automatically determined based on this detection data, and therefore human intervention can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a reticle defect inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a foreign substance inspection apparatus used therein.

FIG. 3 is a schematic perspective view showing the drift correction device.

FIG. 4 is a plan view showing a reticle.

FIG. 5 is a perspective view showing a reticle cassette.

FIG. 6 is an explanatory diagram for explaining the operation of the foreign matter inspection device.

FIG. 7 is an explanatory diagram for explaining the determination operation.

FIG. 8 is a flowchart showing the overall flow.

[Explanation of symbols]

1 ... Reticle (photomask), 2 ... Glass blank, 3
… Chrome pattern, 4… Alignment mark, 5, 6…
Foreign matter, 9 ... Reticle cassette, 10 ... Stepper (exposure device), 11 ... Reticle defect inspection device, 12 ... CPU,
Reference numeral 13 ... Stocker, 14 ... Foreign matter inspection device (defect inspection execution unit), 15 ... Judgment unit / foreign matter management system, 16 ... Transfer device, 17 ... Controller, 20 ... Oblique illumination device, 21
... Condensing lens, 22 ... Imaging lens, 23A, 23B ... Detector, 24 ... Shading element, 25 ... Half mirror, 26 ... Lower illuminating device, 27 ... Phase element, 28 ... Condensing lens, 30
A, 30B ... Signal processing circuit, 31A, 31B ... Quantization circuit, 32 ... Operation circuit, 33 ... Storage unit, 34 ... Comparison circuit,
40 ... Laser light (inspection light), 41 ... Drift correction device,
42 ... Galvano mirror, 43 ... Photo sensor, 44 ... Controller, 45 ... Galvano mirror drive device, 46 ... Scan area.

Claims (3)

[Claims] 1. A defect inspection apparatus for a photomask, which supplies an inspected photomask to an exposure apparatus, comprising: a storage unit for storing a plurality of photomasks; and an inspection execution unit for executing defect inspection of the photomask and detecting defects. A determination unit that determines whether or not the photomask can be used based on the inspection result of the inspection execution unit; and a transfer device that transfers the photomask between the storage unit, the inspection execution unit, and the exposure apparatus. Photomask defect inspection equipment. 2. The inspection execution unit includes a defect detection unit that detects a defect in the photomask, and a storage unit that stores data about the position of the defect in the photomask and the size of each defect based on the detection by the defect detection unit. The determination unit includes an arithmetic unit that collates a plurality of pieces of data regarding the position of a defect and the size of each defect in the same photomask based on the storage data of the storage unit. The defect inspection apparatus for a photomask according to claim 1. 3. The defect inspection apparatus for a photomask according to claim 2, wherein the defect detection means is configured to identify a defect position by coordinates based on a reference mark set on the photomask.