KR101183324B1 - Method for correcting defect of photomask, apparatus for correcting defect of photomask, head for correcting defect of photomask, and apparatus for inspecting defect of photomask and method for manufacturing photomask - Google Patents

Abstract

It is a defect correction method of a photomask which removes a foreign material defect on a photomask using a some probe. That is, a plurality of probes are prepared, and at least two of them are brought into contact with the foreign material on the photomask surface at the same time, the foreign material is held in at least three different places, and the foreign material is kept away from the photomask surface. By leaving, the foreign material defect on a photomask is removed and correct | amended.

Description

Defect correction method for photomask, defect correction device for photomask, defect correction head for photomask, and defect inspection device for photomask and manufacturing method of photomask {METHOD FOR CORRECTING DEFECT OF PHOTOMASK, APPARATUS FOR CORRECTING DEFECT OF PHOTOMASK, HEAD FOR CORRECTING DEFECT OF PHOTOMASK, AND APPARATUS FOR INSPECTING DEFECT OF PHOTOMASK AND METHOD FOR MANUFACTURING PHOTOMASK}

The present invention relates to a defect correction method for photomasks, a defect correction apparatus for photomasks, a defect correction head for photomasks, and a defect for photomasks, which are related to photomasks for manufacturing such as semiconductors such as LSI and flat panel displays (FPD). An inspection apparatus and a manufacturing method of a photomask are related.

Conventionally, the following method is proposed as a method of removing and correcting foreign material defects on a photomask from a photomask.

For example, Japanese Patent Application Laid-Open No. 2005-84582 (Patent Document 1) describes a scanning probe microscope having a scanning probe microscope having a tweezer function by removing the scanning probe microscope probe from the side of the particle by moving the particles. Disclosed is a method of removing particles from a photomask by sandwiching particles with a probe.

Further, Japanese Patent Laid-Open No. 2008-311521 (Patent Document 2) discloses a method for removing from a photomask by pinching and lifting particles on a photomask with a micro tweezer having a pair of arms that can be opened and closed. .

Foreign matter such as particles adhering on the photomask is transferred to a transfer target such as a semiconductor wafer at the time of exposure using the photomask, resulting in defects, and finally, defects in the device. In recent years, the mask pattern has been miniaturized, and the allowable foreign material defect size is also decreasing with it, and it is an important subject to reduce foreign material defects.

However, the foreign matter attached on the photomask has various aspects, and the action of simply pressing the scanning probe microscope probe on the side of the particle to move the particle, or to lift the particle in between with a single tweezers shape. By itself, there is a limit to the kind of foreign material defects that can be corrected.

For example, if a foreign object having a shape that is difficult to be pinched by a tweezers is difficult to be gripped by a foreigner unless it is a highly skilled operator, and even if such a foreign material is held once, it may fall on the photomask while moving. . In any case, there is a problem that the correction of defects depends on the skill of the operator.

In addition, even a skilled operator, using a single tweezers shape, can reliably correct foreign matter defects of various shapes, sizes, and attachment states made of various materials, and it is very difficult to correct them. It takes time to work and is not realistic.

In particular, in the case of the FPD photomask, the defects occurring on the photomask are also different from the defects occurring on the LSI photomask for reasons such as low cleanness of the manufacturing environment compared to the LSI photomask. In addition, since the area of the pattern formation portion of the FPD photomask is large, the defect generation rate may naturally increase. Therefore, especially for FPD photomasks, it is required to stably and reliably correct foreign material defects such as various shapes and sizes made of various materials, and conventional methods for correcting foreign material defects cannot be adopted.

As a method of correcting a foreign defect on a photomask, there is a method by laser irradiation (laser repair) used for the correction of black defects. However, this method is used because the problem of damage to the surface of the photomask by laser irradiation is concerned. There are limitations to the application.

This invention is made | formed in view of such a conventional problem, The defect correction method for photomasks and the photo which can perform stable and reliable defect correction with respect to the foreign material defect of a various aspect in material, shape, size, affixation state, etc. An object of the present invention is to provide a defect correction apparatus for a mask, a defect correction head for a photomask, a defect inspection apparatus for a photomask, and a manufacturing method of a photomask.

In order to achieve the above object, the present invention can be represented by various aspects listed below.

(Aspect 1)

A method for correcting a defect of a photomask in which a foreign material defect on a photomask is removed by using a probe, wherein a plurality of probes are prepared, and at least two of the probes are brought into contact with the foreign material on the photomask surface at the same time, thereby providing at least the foreign material. A method for correcting a defect of a photomask, which is held at three different places and is kept away from the surface of the photomask.

(Aspect 2)

At least one probe of a some probe has a means for clamping the said foreign material, The defect correction method of the photomask of aspect 1 characterized by the above-mentioned.

(Aspect 3)

At least one probe of a some probe has a means for sticking and holding the said foreign material, The defect correction method of the photomask of aspect 1 or 2 characterized by the above-mentioned.

(Aspect 4)

Adjusting the observation optical system so that the region containing the foreign material defect and at least one probe are located within the same field of view of the observation optical system for performing while correcting the foreign material defect, while viewing the observation image of the observation optical system, By contacting at least one probe with the photomask surface of the periphery of the foreign matter defect, the relative position of the probe and the photomask surface is grasped, the defect of the photomask according to any one of aspects 1 to 3 characterized by the above-mentioned. How to fix.

(Aspect 5)

The method for correcting a defect of the photomask according to any one of aspects 1 to 4, wherein the vibration generated in the probe is suppressed by bringing at least one probe into contact with the surface of the photomask.

(Aspect 6)

Said photomask is a multi-gradation photomask for flat panel displays which has a light shielding part, a light transmitting part, and a semi-transmissive part, The defect correction method of any one of aspect 1-5 characterized by the above-mentioned.

(Aspect 7)

The defect correction method of the photomask of aspect 6 characterized by correcting the foreign material defect on the said translucent part.

(Aspect 8)

A method of manufacturing a photomask having a pellicle on a surface of a photomask, wherein the defect is corrected by a method for correcting a defect of the photomask according to any one of aspects 1 to 7 before mounting the pellicle. Method for producing a photomask.

(Aspect 9)

A defect correction apparatus for photomasks that corrects foreign material defects on a photomask, comprising: a photomask holder holding a photomask, an observation optical system for observing a desired position on the photomask, and an observation for moving the observation optical system to a desired position Optical system moving means, a plurality of probes used to remove foreign substances on the photomask, and moving the plurality of probes in a direction perpendicular to the photomask surface and in a plane parallel to the photomask surface; And a probe movement means for approaching a desired position on the surface of the photomask.

(Aspect 10)

The defect correction apparatus for a photomask according to aspect 9, wherein the plurality of probes are accessible from the different directions with respect to the foreign material by the probe moving means.

(Aspect 11)

At least one of the said plurality of probes has a means for clamping the said foreign material, and the other at least 1 has a means for sticking and holding the said foreign material, The defect correction apparatus for photomasks of aspect 9 or 10 characterized by the above-mentioned.

(Aspect 12)

The defect correction apparatus for photomask according to any one of aspects 9 to 11, wherein the probe is formed of a material having a range of 4 to 7 at a ten-stage Mohs hardness, at least.

(Aspect 13)

The defect correction apparatus for a photomask according to Embodiment 12, wherein the probe has at least a contact portion to the photomask made of a material containing silicon (Si) as a main component.

(Aspect 14)

The apparatus for correcting defects for photomasks according to any one of aspects 9 to 13, further comprising static eliminating means for reducing the potential difference between the probe and the photomask.

(Aspect 15)

It provided with the defect inspection means of a photomask, The defect correction apparatus for photomasks in any one of aspect 9-14 characterized by the above-mentioned.

(Aspect 16)

A defect correction head for a photomask that removes a foreign material defect on a photomask, comprising: an observation optical system for observing a desired position on the photomask, a plurality of probes used to remove the foreign material on the photomask, and the foreign material And a probe operating means for allowing the plurality of probes to approach the foreign object from any direction in a state within the field of view of the observation optical system.

(Aspect 17)

The defect inspection apparatus for photomasks provided with the photomask-defect head of aspect 16 characterized by the above-mentioned.

According to the present invention, defects can be fixed stably and reliably with respect to foreign material defects having various materials, shapes, sizes, adhered states, and the like. Therefore, in particular, defect correction in a photomask having a variety of kinds of foreign material defects, such as a large size photomask such as a multi-gradation photomask for FPD, can be suitably coped with.

BRIEF DESCRIPTION OF THE DRAWINGS The figure explaining an example of the defect correction method using the 1st probe which has a means which clamps a foreign material, and the 2nd probe which has a means which hold | maintains a foreign material on the surface by adhesion.
FIG. 2 is a view for explaining an example of a defect correction method in the case of having a means for holding a foreign material between both the first probe and the second probe. FIG.
3 is a diagram showing a schematic configuration of a defect correction apparatus for a photomask of the present invention.
4 is a diagram showing a schematic configuration of a defect correction head portion in a defect correction apparatus for a photomask of the present invention.

EMBODIMENT OF THE INVENTION Below, this invention is demonstrated in detail by embodiment, referring an accompanying drawing suitably.

Embodiment 1 of the present invention is a method for correcting a defect of a photomask in which a foreign material defect on a photomask is removed using a probe, wherein a plurality of probes are prepared, and at least two probes are used for a foreign material on the photomask surface. By contacting at the same time, the foreign material is held in at least three different places, and the foreign material is kept away from the photomask surface.

Two or more probes, such as a 1st probe and a 2nd probe, are used for the correction of the foreign material defect on a photomask. The size of the foreign material defect which exists on a photomask is about 0.5-100 micrometers normally. As described later, the probe can be produced by microfabrication such as photolithography. The defect correction of the photomask of the present invention is preferably performed at a place where particles and temperature and humidity environment, such as a clean room, are managed.

Here, a probe is a member which can come into contact with the foreign material defect of the said size on the photomask surface, and can exert a force with respect to a foreign material, and the tip was processed to the needle shape by the process, and the tweezer-shaped clamping means It is to include a thing that has been processed, the one provided with an adhesive material at the tip so that the foreign matter can be kept adhesive, the thing of the shape that can be carried by moving the foreign material on the upper surface. In addition, as will be described later, the probe is a shape capable of exerting a necessary force against a foreign material without causing new defects on the photomask surface under the premise of contacting the photomask surface during the defect correction operation, and It is preferable to have rigidity. The shape, rigidity, and the like of the probe will be described later.

The foreign material (defect) to be corrected refers to a foreign material such as a so-called particle or the like attached to the photomask blank at the stage of the photomask blank or at the photomask manufacturing stage or after the photomask manufacturing, and the like, such as a resist piece or a light shielding film. Particles or particles in the atmosphere, including all particles and the like, not limited to organic or inorganic.

The photomask includes a photomask intermediate during manufacture in addition to the formation of a transfer pattern. That is, in each step in which a photomask as a final product is manufactured, it includes a substrate, a thin film or a resist film (photo mask blank), and a part of the thin film is patterned.

As described above, only a single probe having a conventional means for pinching defects such as tweezers can be varied in material and shape, and its size is also in a wide range of about 0.5 to 100 µm, and the state of attachment to the photomask surface. It is very difficult to reliably correct foreign material defects having various aspects.

In the actual correction operation, the operator performing the defect correction operation finds a point where the foreign material defect to be removed can be reliably pinched by, for example, a tweezers-shaped probe, and the pinching point is reliably used by the probe. If it can pinch, defect correction can be performed. However, for this purpose, the operator who performs corrective work requires considerable skill, and there must be a location where the foreign material defect itself can be reliably held by the probe. Otherwise, even if foreign matter defects can be interposed once, there is a high possibility that foreign matters fall from the probe while the foreign matters are lifted and conveyed outside the region of the photomask surface. The foreign matter that has fallen may fall on the photomask and scatter, resulting in new defects.

Alternatively, depending on the shape of the foreign material defect, it may not be possible to intervene at first, and therefore, the foreign material cannot be corrected by pinching and moving the foreign material. For example, in a foreign material having a smooth surface such as a spherical shape, even if it is intended to sandwich the probe with a single means for holding the foreign material in a single state, the foreign material can only come into contact with a dot or the surface. Because of this smoothness, it is difficult for a skilled operator to pinch well.

In the defect correction method described above, a plurality of probes are used, and at least two of them are brought into contact with the foreign material on the photomask surface at the same time to hold the foreign material. Thereby, even if it is not necessarily an experienced operator, even if the foreign material which does not exist the position which can be reliably pinched by a single probe can be maintained, Furthermore, while holding the foreign material which was hold | maintained and conveyed it out of the area of the photomask surface, There is no worry of foreign matter falling from the probe, and more reliable and reliable defect correction can be performed.

In addition, in the defect correction method described above, by using a plurality of probes, the foreign material on the photomask surface is held at at least three different positions so that the foreign material can be reliably held and lifted. As a result, more stable and reliable defect correction can be performed.

Next, with reference to FIG. 1, an example of embodiment of the defect correction method of the photomask which concerns on this invention is demonstrated. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the example of the defect correction method using the 1st probe which has a means which clamps a foreign material, and the 2nd probe which has a means which hold | maintains a foreign material on the surface by adhesion.

In this embodiment, the 1st probe and the 2nd probe contact the foreign material simultaneously, and the example which hold | maintains the foreign material and moves is shown.

First, the foreign material (defect) 2 on the photomask 1 is clamped using the 1st probe 3 which has a means for clamping a foreign material (refer FIG. 1 (a), (b)). Next, the foreign material 2 is brought into contact with the foreign material 2 using the second probe 4 having the means for holding the foreign material on the surface by adhesion, and the foreign material 2 is adhered to the adhesive material on the surface thereof (( c)). In this way, when the 1st probe 3 and the 2nd probe 4 contact the foreign material 2 simultaneously, the foreign material 2 can be held stably and reliably. In addition, since the 1st probe 3 and the 2nd probe 4 contact the foreign material 2 at the same time in this way, it maintains an unstable state only by holding | maintenance of two places by clamping, and one more place by adhesion. In other words, by using the first probe 3 and the second probe 4, the foreign material 2 can be held at least at three different positions, whereby the foreign material 2 can be held reliably, and the foreign material can be separated from the probe. There is no worry.

Next, if the first probe 3 and the second probe 4 are kept away from the photomask 1 surface while maintaining the state of the foreign material 2, the foreign material (from the surface of the photomask 1) 2) is removed (see FIG. 1D). Subsequently, in the state where the 1st probe 3 and the 2nd probe 4 hold | maintained the foreign material 2, it moved to the position of the adhesion member 5 outside the area | region of the photomask surface (refer FIG. 1 (e)). ), The foreign material 2 is brought into contact with the adhesive member 5 (see (f) of FIG. 1), and then the foreign material 2 is opened from the first probe 3 and the second probe 4, and the respective foreign materials 2 are opened. When the probe is kept away, the foreign material 2 is captured by the adhesive member 5, and defect correction on the foreign material 2 is completed. In the case where a plurality of foreign matter defects exist on the photomask 1, the defect correction may be performed in the same manner with respect to the remaining foreign matter defects. In this embodiment, even if the probe 4 is brought into contact with the foreign material for the first time and the probe 3 is brought into contact with the foreign material, there is no problem. Further, the probe 3 and the probe 4 may be brought into contact with the foreign material simultaneously (at completely the same timing) from different directions.

Next, with reference to FIG. 2, another example of embodiment of the defect correction method of the photomask which concerns on this invention is demonstrated. FIG. 2: is a figure explaining an example of the defect correction method in the case of having a means which clamps a foreign material in both a 1st probe and a 2nd probe.

Also in this embodiment, the 1st probe and the 2nd probe contact the foreign material simultaneously, and the example which hold | maintains the foreign material and moves is shown.

First, the foreign material (defect) 2 on the photomask 1 is clamped using the 1st probe 6 which has a means for clamping a foreign material (refer FIG. 2 (a), (b)). Next, similarly to the part clamped by the said 1st probe 6 of the foreign material 2 using the 2nd probe 7 which has a means which clamps a foreign material similarly, FIG. c)). In this way, when the 1st probe 6 and the 2nd probe 7 contact the foreign material 2 simultaneously, the foreign material 2 can be stably and reliably held. In this way, both of the first probes 6 and the second probes 7 having the means for holding the foreign materials in contact with the foreign material 2 at the same time were in an unstable state only by holding of two places by the holding of one probe. The two more parts are held by the clamping of another probe. That is, by using the 1st probe 6 and the 2nd probe 7, by holding the foreign material 2 in four other places, the foreign material 2 can be hold | maintained reliably, and the foreign material may fall further from a probe. There will be no.

Next, when the first probe 6 and the second probe 7 are kept away from the photomask 1 surface while keeping the foreign material 2 held, the foreign material (from the surface of the photomask 1) 2) is removed (see FIG. 2 (d)). Subsequently, in the state where the 1st probe 6 and the 2nd probe 7 hold | maintained the foreign material 2, it moved to the position of the adhesion member 5 outside the area | region of the photomask surface ((e) of FIG. 2). After the foreign material 2 is brought into contact with the adhesive member 5 (see FIG. 2 (f)), the foreign material 2 is released from the first probe 6 and the second probe 7, respectively. The foreign material 2 is trapped by the adhesive member 5, and the defect correction with respect to this foreign material 2 is completed.

Moreover, also in this embodiment, you may make the probe 7 contact a foreign material for the first time, and may make the probe 6 contact next. Further, the probe 6 and the probe 7 may be brought into contact with the foreign material at the same time (at exactly the same timing) from different directions.

Here, the attachment position of the adhesive member 5 is not attached to the probe or the optical system for monitoring the crystal, but is reattached onto the photomask even if foreign matter is separated from the adhesive member, such as outside the photomask surface. It is preferable to install in the position which does not. Or it is preferable to consider the flow of the airflow around a photomask, etc. in consideration of the case where a foreign material fell, and to set it as the position below airflow rather than a photomask.

In addition, the adhesive member 5 can be used not only for the collection of defective foreign materials but also for cleaning of foreign matter (contaminants of probes different from defects derived from photomasks) attached to the probe before correction. For example, the foreign material confirmed on the probe operates the probe while observing the monitor, and the portion to which the foreign material is attached is brought into contact with the adhesive member 5 to secure the foreign material on the adhesive member 5. The probe can be cleaned. Therefore, the foreign matter on the probe can be modified using a clean probe without moving to the photomask and attaching it.

Alternatively, if a mirror or the like having a mirror surface is provided around the adhesive member 5 in the same direction as the crystal surface side of the photomask, the foreign matter attached to the probe can be confirmed by passing through an optical system for monitoring the correction operation.

In the embodiment shown in FIG. 1 and FIG. 2, the shape of the foreign material defect is close to a spherical shape. Even if the shape of the foreign material defect is close to a spherical shape and is intended to be clamped by using a single probe having a clamping means having a shape such as tweezers, there are only two contact points with the probe, so that it can be stably held. However, in addition to the first probe, the second probe is brought into contact with the foreign material at the same time from another direction, whereby the contact point with the foreign material is increased, and the foreign material can be maintained at at least three different places.

Moreover, the defect correction method mentioned above can respond suitably also to the aspect of a foreign material defect different from what was demonstrated in the said embodiment. For example, when the shape of a foreign material defect is a planar shape and the photomask surface and the surface of a foreign material defect are affixed in the form which contacted each other, it is difficult to hold | maintain a foreign material defect in this state. In that case, the foreign material defect is lifted up using, for example, one of the two probes, and then the other one probe is held by the other probe. In some cases, the contact position with respect to a foreign material may be changed by pinching again by the probe which raised the foreign material defect at the beginning. As a result, even in the case of a foreign material defect in which the shape is flat in a flat shape with respect to the photomask surface, the foreign material can be reliably held in at least three different places by a plurality of probes, and there is a fear of dropping the foreign material defect. There will be no.

In addition, it is preferable to perform a defect correction after the foreign material defect of the state which adhered strongly to the photomask surface first by using any one probe to scrape off the foreign material defect from the photomask surface.

In the above-described embodiment, one of the two probes is a probe having a means for holding a foreign material, and the other is a probe having a means for sticking and holding a foreign material, or both probes hold the foreign material. Although the case where the probe has a means was demonstrated, it is not limited to this, For example, you may use at least 1 probe with a needle-shaped contact means at the front-end | tip. For example, in the case where the first probe has a clamping means and the second probe has a needle-shaped contact means, these probes simultaneously contact the foreign material, thereby maintaining three places from the other direction with respect to the foreign material. It is possible.

In the case of performing various defect correction operations, including any one of the above-described defect correction methods, the ease of maintenance by the probe in each foreign matter defect may be different. For example, a foreign material defect that is considered to be easy to hold using only one probe by using a probe having a means for holding a foreign material may be held by only one probe, but in reality, the foreign material defect Since there is no method of confirming whether it is hold | maintained by a probe reliably, it is preferable to hold | maintain such foreign material defect in three or more places. Thereby, the foreign material defect will not fall from a probe by the vibration or airflow which arises when moving the foreign material defect removed from the photomask surface to the adhesion member 5 located in the place away from a correction point.

In addition, a plurality of probes are used, and the present invention is not limited to the case where two probes, a first probe and a second probe, are used as in the above-described embodiment. That is, in order to correct | amend defects, you may use another probe other than a 1st probe and a 2nd probe.

In addition, in the above-described embodiment, the positional relationship between the probe and the foreign material defect is merely an example, and the positional relationship between the probe and the foreign material defect varies depending on the aspect of the actual foreign material defect and the like. It should not be limited only to the embodiment.

Next, the material of the said probe is demonstrated.

The probe may directly contact the photomask at the time of defect correction, and the foreign material defect strongly adhered to the photomask may be scraped off the surface of the photomask by acting by scraping off the probe. Therefore, as a probe material, it is preferable that at least the contact part with respect to a photomask is a material which does not damage the surface of a photomask.

As a probe material which can reliably correct foreign material defects and does not damage the photomask, a material in the range of 4 to 7 in a ten-stage Mohs hardness is preferable. The Mohs 'Hardness of the quartz glass used as the substrate of the photomask is 7, and when the Mohs' Hardness of the probe is larger than 7, the damage to the photomask is easily caused. On the other hand, when the Mohs hardness of the probe is less than 4, a photomask composed of a pattern of quartz glass and a metal thin film (chromium compound or the like), on the contrary, tends to damage the probe. This causes a problem.

As a material satisfying the above Mohs hardness range, for example, a material containing silicon (Si) as a main component can be used. A material containing Si as its main component (Si single element or Si content of 95 atomic% or more) has a Mohs' hardness of 7 and can be processed by photolithography, so that fine probes can be mass-produced with high precision. Similarly, the quartz glass used as the material of the photomask can also be used as a probe because of its Mohs hardness of 7 and easy processing.

On the other hand, the probe can be manufactured by a grinding machine corresponding to micromachine manufacturing or by machining using a FIB (convergence ion beam). In this case, the probe is not limited to the processing constraints of photolithography. It is not restricted to materials. According to such a machining, it becomes possible to manufacture the probe of a three-dimensional shape with more freedom. For example, by adding a shape such as a knife edge suitable for scraping foreign material defects to a part of the probe, or roughening the surface to the part where the foreign material defects of the probe are sandwiched so as to easily catch foreign material defects. Etc. are also possible. Of course, it is also possible to produce a combination of both photolithography and machining.

In addition, the surface of the probe may be surface treated with a fluorine resin, an olefin resin, or the like in order to form an oxide film layer to prevent corrosion of the probe or to easily handle sticky foreign material defects.

The surface treatment of the probe also includes the purpose of imparting insulation to the probe surface. The basic constituent material of the photomask mainly includes a glass substrate such as quartz glass, a thin film, and the like, such as chromium, an oxide thereof, a nitride, another metal compound, an inorganic compound, and the like, and is easily electrostatically charged. Therefore, when the photomask is electrostatically charged and the correction is performed in a state where a potential difference is generated between the probe, current is generated between them, and sometimes a problem such as damage to the mask pattern due to discharge destruction occurs. In order to prevent this, by providing a high insulation property on the probe surface or the probe itself, which is the part that most approaches the photomask at the time of correction, even if a potential difference is generated between the photomask and the probe, the mask pattern is broken. It is possible to suppress the large current from flowing at once.

The defect correction method described above is particularly suitable for defect correction of a multi-gradation photomask for FPD. In the case of the FPD photomask, the defects occurring on the photomask also differ from the defects occurring on the LSI photomask due to the low cleanness of the manufacturing environment compared to the LSI photomask. . For example, the diversity of defects is increased in comparison with the photomask for LSI, such as a large defect size or a large variety of types or shapes of materials constituting the defect. In addition, since the area of the pattern forming portion of the FPD photomask is large, the defect occurrence rate may naturally increase. In particular, the FPD photomask has a variety of shapes, sizes, and attachment modes made of various materials. Since it is required to correct this large foreign material defect stably and reliably, the above-mentioned defect correction method is preferable.

In addition, there is another reason why the above-described defect correction method is particularly preferable for defect correction of a multi-gradation photomask for FPD.

In a multi-gradation photomask for FPD having a light shielding portion, a light transmitting portion, and a semi-transmissive portion on a transparent substrate such as quartz glass, the foreign matter defect on the semi-transmissive portion is the same as that of the foreign matter defect on the light-transmitting portion. At the time of exposure to the transfer target, the transfer target is also transferred to the transfer target as a surplus defect. Therefore, the foreign material defect on the translucent part must also be corrected as a surplus defect. By the way, when the defect on a thin film is correct | amended with a laser corrector etc., there existed a problem that the thin film of the periphery including the under directly of a defect was also damaged by laser irradiation, and a damage defect will become a defect if a damage is large. In the case of a light shielding part, even if a missing defect occurs, it is relatively easy to correct the damage part received by laser irradiation by forming a light shielding film for correction. However, when damage is caused to the semi-transmissive portion by laser irradiation, the transmittance of the semi-transmissive portion is varied. In the case of a multi-gradation photomask, the permissible range of the transmittance fluctuation of the semi-transmissive portion is very narrow, and therefore it is difficult to form a crystal film having a desired transmittance and high durability in the damage portion, which is difficult to actually correct. Therefore, when the foreign matter defect on the translucent part cannot be removed by washing | cleaning, there is a problem in performing laser correction, and eventually the photomask which cannot fix a defect may become a defective product.

The above-mentioned defect correction method has a big merit that defects can be corrected even without such damage to the foreign material on the semi-transmissive portion at all, thereby reducing the incidence of defective products resulting from defects on the semi-transmissive portion. It becomes possible.

In addition, the said transflective part is formed of the transflective film which consists of materials, such as MoSi, for example. The probe made of a material containing Si as a main component damages the thin film portion in defect correction involving contact of the probe, not only in the quartz glass of the photomask constituent material but also in the defect correction on the thin film such as MoSi or chromium compound. Since defect correction can be performed without letting it happen, this is also advantageous.

Next, the defect correction apparatus suitable for implementing the defect correction method of the photomask mentioned above is demonstrated.

3 is a diagram illustrating a schematic configuration of a defect correction apparatus for a photomask of the present invention. 4 is a diagram showing a schematic configuration of a defect correction head portion in the defect correction apparatus for photomask of the present invention.

The defect correction apparatus for photomasks shown in FIG. 3 has shown one Embodiment, and the photomask 1 which correct | amends defects in the inside of the main body frame 9 provided on the mount 10 in the upright position was made vertically. A holder 8 for attaching and fixing, a defect correction head portion 15 including a plurality of probes and an observation optical system, an X axis, a Y axis for moving the defect correction head portion 15 in three directions of XYZ, and Each stage 11, 12, 13 of Z-axis, the antistatic means 14, etc. are arrange | positioned.

Moreover, the defect correction head part 15 is equipped with the some probe 16,19 and the optical system 22, as shown in FIG. Here, the case where two probes are provided as an example is shown, For convenience of description, the code | symbol 16 is called a 1st probe and the code | symbol 19 is called a 2nd probe. These 1st probe 16 and the 2nd probe 19 are equipped with the means which clamps a foreign material, the means for sticking and holding a foreign material, etc. as mentioned above.

Since foreign matter defects having various aspects are treated with two probes, the first probe 16 and the second probe 19 are respectively provided at the tips of the probe moving arms 17 and 20 which can be precisely moved in three directions of XYZ. Attached. The arm moving mechanisms 18 and 21 control the movement of each of the probe moving arms 17 and 20 in the XYZ directions, respectively. In addition, the arm movement mechanisms 18 and 21 and the optical system case 23 which arrange | positioned the optical system 22 at the front-end are respectively attached to the predetermined position of one surface of the L-shaped common attachment base 24 from planar view, respectively. have. Moreover, the whole of the common attachment base 24 which attached the said arm movement mechanisms 18 and 21 and the optical system case 23 by the head part rotation mechanism 25 attached to the rotation mechanism attachment base 26 is an example. For example, it is configured to rotate within the range of 0 to 90 degrees.

The defect correction operation is performed while observing an image enlarged through the optical system 22 with a monitor. Therefore, the 1st probe 16 and the 2nd probe 19 respectively attached to the probe movement arms 17 and 20 are comprised so that the range required for defect correction may be moved within the visual field of the optical system 22. As shown in FIG. In addition, the detail of an optical system is demonstrated further later. In addition, the probe movement arms 17 and 20 are the arrangement suitable for handling the foreign material defect by the 1st probe 16 and the 2nd probe 19 attached to each, for example, the center of an observation visual field. It can arrange | position to both sides centering on. In this case, each probe 16 and 19 can approach a foreign material defect from a different direction, respectively.

For example, as shown in FIG. 4, when two probes are provided, the front end of each probe can be arrange | positioned so that it may face nearly 180 degree | times. In addition, when the probe is 3, there is a method of arranging each probe to face almost 120 degrees. However, this is merely an example. If the shape of the probe or the operating mechanism of the arm for moving the probe changes, various arrangements can be considered. It does not limit the scope of the present invention.

In the pattern of the photomask, there are patterns having various angles, such as a pattern used for wiring lines, in addition to a pattern mainly composed of edges perpendicular to each other, such as pixel patterns and electrode pads. In addition, the position which is most easy to hold | maintain a foreign material defect on a photomask varies with the aspect of a foreign material defect. Therefore, in actual defect correction, it is desirable to increase the degree of freedom of operation for moving the probe to the position where the foreign matter defect is most easily maintained.

In the configuration shown in FIG. 4, the first probe 16 and the second probe 19 can be moved in three directions of XYZ, respectively, by the probe movement arms 17 and 20. It rotates for every common attachment base 24 to which the moving mechanisms 18 and 21 and the optical system case 23 were attached, and centered on the center of the viewing field of the optical system, in a plane parallel to the photomask surface, that is, the viewing field of view. The probes 16 and 19 can be rotated. Thereby, a selection is made in consideration of the shape and posture of the foreign matter, taking into consideration the direction in which the pattern edge is not damaged, and then the two probes 16 and 19 are brought close to each other to correct and hold and remove the foreign matter. . In this way, the degree of freedom of movement for moving the probe to the position where the foreign matter defect is most easily maintained increases, and the foreign matter defect can be maintained and removed more reliably.

In addition, the optical system 22 for observing foreign material defects (i.e., defect correction points) includes a low magnification lens for roughly positioning the correction points, a high magnification lens for correcting minute defects, and some of them taking intermediate use thereof. It is comprised by two medium magnification lenses. Although these optical lenses can switch a plurality of single lenses using a revolver etc., the method of covering the above magnification range using a zoom lens etc. is preferable. In addition, since the probe moves in the space between the optical system and the photomask to perform a correction operation, it is preferable that the optical lens used for the optical system has a long operating distance. In order to secure the working space of the probe, it is preferable that the working distance is at least several mm and possibly at least 10 mm.

Moreover, it is preferable that the optical system 22 is equipped with the illuminating device (not shown) for illuminating a defect position and its periphery during a correction | amendment operation. Since the actual foreign matter defect may be difficult to observe from the shape and the material depending on the kind of illumination, the illumination is a color for changing the quality of light, such as coaxial fall light, dark field illumination, transmission illumination, etc. It is preferable to equip a filter, a deflection filter, etc., and to equip that which can observe various defects more reliably.

In addition, in order to correct in a good field of view with proper focus, it is preferable to provide a means for autofocus so that the distance between the photomask and the lens tip is kept constant and the lens tip does not contact the photomask. . For example, the type of autofocus includes the use of laser reflection and the use of image contrast on the focus surface. The photomask does not depend on the state of the photomask pattern because there is a part in which there is no contrast pattern, for example, only a glass part or only a pattern part exists in the reference range for focus. What used the reflection of the laser which is a focus method is preferable.

However, it is difficult to accurately determine the relative position (distance) between the probe and the photomask by using only the above auto focus means, so that the defect correction point may be moved to move the probe to a desired position. Apart from the optical system for observation, a means for identifying the relative position of the probe and the photomask is required. Since it is difficult to accurately grasp the relative positional relationship between the photomask and the probe only from the image within the observation field of view, the following method is used.

First, as described above, the autofocus means is focused on the surface of the photomask to determine the distance between the optical lens and the surface of the photomask. While referring to the distance, the probe approaches and contacts the photomask surface. At this time, the position where the probe contacts the photomask is a position where the distance between the probe and the photomask becomes O (zero). By performing defect correction on the basis of this position, the correction can be performed while accurately identifying the relative position of the probe and the photomask.

As described above, since the contact portion of the probe with respect to the photomask is made of a material which is hard to damage the photomask surface, it is possible to position the probe as described above without any problem.

By attaching the optical system case 23 and the arm moving mechanisms 18 and 21 to the common attachment base 24, the defect correction head portion integrating the optical system 22 and the plurality of (16) probes 16 and 19 ( 15) moves on the stages 11, 12, 13 of the X-axis, Y-axis, and Z-axis for moving it in three directions of XYZ to the desired position of the photomask 1. As described above, the relative positions of the photomask 1 and the defect correction head portion 15 are relatively moved, whereby the defect correction head portion 15 can be positioned at a desired position of the photomask 1. Foreign material defects captured within the observation field of the desired position of 1) can be corrected.

By the way, the information about the defect position of a photomask turns out according to the result confirmed by the confirmation by the eye, the inspection by a microscope, or the defect inspection apparatus. In the case of eye confirmation or inspection of a microscope, it is necessary to set it in the above-mentioned defect correction apparatus based on its approximate position, and then search the surroundings again to find a defect, but also coordinate the stage with a microscope or the like. A numerical value may be displayed, and the defect inspection apparatus can record the position of a defect as coordinate numerical data. When the coordinate value is used for the defect correction apparatus in the form of input or data file input, an efficient defect search can be performed, and no correction omission or the like can occur, thereby improving reliability. Specifically, a photomask to be corrected is provided in the defect correction apparatus described above, a coordinate value (data, etc.) of a defect position of the photomask is input, and the correction head portion is a desired position of the photomask (first defect position). ) Is moved using stages 11 to 13 of XYZ. When the first defect correction is completed, the correction head portion is moved to the position of the next defect and the defect correction is performed. In this way, when all defects are corrected, the photomask is taken out.

In addition, in this embodiment, in order to reduce the electrostatic charge mentioned above, in order to reduce the electrostatic charge amount of the apparatus containing a photomask and a probe, the antistatic means 14 is provided in the upper part in the main body frame 9, have. In addition to the purpose of bringing the potential difference between the probe and the photomask to approximately zero, this method introduces an electrostatically unnecessary foreign matter defect caused by charging to the photomask surface and does not increase the adhesion of new defects. The purpose of the present invention is to reduce the attraction force due to static electricity between photomasks and to facilitate correction. Therefore, it is preferable that the antistatic means 14 reduces both the charge amount of a photomask and the charge amount of the probe which contact | connects a photomask, Preferably it adjusts so that it may be substantially close to zero. Since the amount of static electricity cannot be confirmed by the eye, a monitor capable of confirming the potential difference between the probe and the photomask and a means for warning when the potential difference is large also prevent the problems caused by the static electricity. This is a preferred method.

The above-mentioned defect correction apparatus is preferable because it can stably and reliably correct very minute foreign material defects in 0.5-100 micrometers also with respect to the photomask of 1 size more than 1m, such as an FPD photomask. In addition, from the point of handling such a large size photomask, it is preferable to take the following countermeasures as an apparatus. For example, after adopting a material having a high rigidity to the portion (mounting) that is the base of the main body, the holder and the main body of the holder for the purpose of ensuring the mechanical position of the holder for fixing the photomask to the device. It is fixed without providing a movable means between bases, and the mechanical rigidity of the base of a main body and a holder is raised.

In the apparatus described above, the photomask is fixed and defect correction is performed by moving the correction head portion to a desired position on the photomask. Thereby, compared with the case where the side of a photomask moves, the space saving of the space to which a photomask moves is made possible, and also the structure with which the high mechanical rigidity of a photomask holder and the base of a main body is hard to generate | occur | produce is a structure.

In addition, depending on the environment in which the device is installed, it is also preferable to add a vibration damping device as necessary to reduce the influence of vibration.

However, even when a vibration of about 1 μm or less in amplitude occurs, for example, between the tip of the probe and the photomask, the above-described apparatus employs a probe made of a material that is hard to damage the surface of the photomask, while contacting the probe on the photomask. Since the defect can be corrected, the defect can be corrected without being affected by vibration of 1 탆 or less.

Alternatively, in order to prevent foreign substances generated in the periphery of the above-described apparatus from falling down on the photomask and staying at the position, specifically, the surface of the photomask follows the direction of the flow of downflow by the clean air in the clean room. It is preferable to prepare a holder for fixing the photomask so as to be perpendicular to the horizontal plane as in the present embodiment (see FIG. 3). At the same time, the above-described apparatus includes antistatic means, so that even if foreign matter approaches the photomask, there is little risk that foreign matter adheres to the photomask due to the attraction force due to static electricity. Further, by installing the photomask perpendicular to the horizontal plane, it becomes possible to reduce the installation area of the apparatus. In addition, since there is no need to prepare additional equipment, such as a loader and an unloader, which are necessary when installing a photomask horizontally, it can be set as a space-saving apparatus.

In addition, when the defect correction head including at least the probe and the observation optical system described above is equipped with a defect inspection apparatus including an optical microscope, it is possible to reduce the trouble of moving the photomask between the apparatuses after defect inspection. Since the risk of contamination of the photomask is reduced, and information such as defect coordinate data can be shared, various merits such as shortening of the process and improvement of quality can be expected. Moreover, there is a similar merit also by equipping the defect correction apparatus described above with a defect inspection means. However, even when a device having only a function of defect correction is used, defect inspection, defect correction, and operation of each individual work can be carried out, and thus there is a merit such as improvement of product tact.

Thus, the above-mentioned method has the merit that even if it uses individually as a correction apparatus, or it uses in combination with a defect inspection apparatus, there is a merit in each and can select what form to take as needed.

Moreover, in the manufacturing method of the photomask which has a pellicle in the photomask surface, defect correction by the above-mentioned defect correction method can also be performed before mounting a pellicle.

In the defect correction method described above, foreign matter defects due to handling during the correction operation are not generated, and new defects do not occur as in the conventional cleaning or laser repair. Without work, the photomask can go directly to the pellicle bonding process. As a result, the time required for re-cleaning and re-defect inspection can be greatly reduced, and the work share for these processes can be reduced, thereby making it possible to significantly reduce the load on the photomask manufacturing line. It also leads to reductions.

As can be seen from the above, it is a defect that cannot be removed by simple cleaning with a cleaner, or a defect located at a part which cannot be removed by a laser repair, for example, a transparent defect or a position which cannot be corrected with respect to a laser beam, or There is a very big merit that it is possible to stably and reliably perform the desired correction even when the laser repair is intended to remove damage, for example, defects on the semi-transmissive portion of the FPD photomask.

Claims (17)

As a defect correction method of a photomask for FPD to remove foreign matter defects on the photomask,
The foreign substance on the photomask surface is removed from the photomask surface using the 1st probe which can pinch a foreign material, and the 2nd probe which can hold | maintain a foreign material with the said 1st probe. How to fix defects on FPD photomask. delete The method of claim 1,
The first probe or the second probe, the defect correction method of the FPD photomask, characterized in that the adhesive is provided on the surface in order to hold the foreign matter. delete delete The method of claim 1,
The photomask is a flat panel display multi-gradation photomask having a light shielding portion, a light transmitting portion, and a semi-transmissive portion having a translucent film formed thereon, and the defect correction method of the FPD photomask. The method of claim 6,
The defect correction method of the FPD photomask, characterized in that to correct the foreign matter defect on the translucent portion. delete A defect correction apparatus of a photomask for FPD that corrects a foreign defect on a photomask,
A photomask holder for holding the photomask,
An observation optical system for observing a defect position on the photomask,
Observation optical system moving means for moving the observation optical system to the defect position;
Defect correction head to remove foreign material on the photomask
Has,
The correction head may include a first probe capable of holding the foreign material, a second probe capable of holding a foreign material together with the first probe, and the first probe and the second probe perpendicular to the surface of the photomask. Probe movement means for moving in a direction parallel to the surface of the photomask, thereby approaching a defect location on the photomask surface
The defect correction apparatus of the FPD photomask, characterized in that it comprises a. delete 10. The method of claim 9,
The first probe or the second probe has a pressure-sensitive adhesive on the surface in order to maintain the foreign matter adhesion, the defect correction apparatus of the FPD photomask. 10. The method of claim 9,
The said 1st probe or the 2nd probe is a defect correction apparatus of the FPD photomask in which the contact part with respect to the said photomask is made from the material of the range of 4-7 with 10 steps Mohs hardness. The method of claim 12,
The defect correction apparatus of the FPD photomask, wherein the first probe or the second probe is formed of a material containing silicon (Si) at least in contact with the photomask. 10. The method of claim 9,
And a static elimination means for reducing the potential difference between the first probe or the second probe and the photomask. 10. The method of claim 9,
A defect correction apparatus for an FPD photomask, comprising: a defect inspection means for the photomask. As a defect correction head of an FPD photomask that removes foreign material defects on a photomask,
A first probe capable of holding the foreign material, a second probe capable of holding a foreign material together with the first probe,
An observation optical system for observing a desired position on the photomask,
Probe movement means for bringing the first probe and the second probe closer to the foreign object while the foreign material is within the field of view of the observation optical system
The defect correction head of the photomask for FPD having a. The defect inspection apparatus of the photomask for FPD provided with the defect correction head for photomasks of Claim 16.

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