阅读说明：本技术 光掩模的修正方法及修正装置、带保护膜的光掩模的制造方法、显示装置的制造方法 (Method and apparatus for correcting photomask, method for manufacturing photomask with protective film, and method for manufacturing display device ) 是由 宫崎由宽 于 2020-03-04 设计创作，主要内容包括：提供光掩模的修正方法及修正装置、带保护膜的光掩模的制造方法、显示装置的制造方法,能够在不从光掩模卸下保护膜的情况下对转印用图案的缺陷进行修正。一种光掩模的修正方法,对光掩模的转印用图案中所产生的缺陷进行修正,该光掩模在透明基板的主表面上具有所述转印用图案,其中,该光掩模的修正方法具有成膜工序,在该成膜工序中,在所述光掩模上粘贴有保护膜的状态下,将原料气体导入到由所述光掩模和所述保护膜形成的保护膜空间中,并且透过所述保护膜具有的保护膜膜体朝缺陷部位照射激光,使所述原料气体发生反应,由此使修正膜堆积在所述缺陷部位。(Provided are a method and a device for correcting a photomask, a method for manufacturing a photomask with a protective film, and a method for manufacturing a display device, which can correct defects in a transfer pattern without detaching the protective film from the photomask. A method of correcting a defect generated in a transfer pattern of a photomask having the transfer pattern on a main surface of a transparent substrate, the method comprising a film formation step of introducing a source gas into a protective film space formed by the photomask and a protective film in a state where the protective film is attached to the photomask, and irradiating a defect portion with a laser beam through a protective film body of the protective film to react the source gas, thereby depositing a correction film on the defect portion.)

1. A method for correcting a defect generated in a transfer pattern of a photomask having the transfer pattern on a main surface of a transparent substrate, wherein,

the method for correcting a photomask comprises a film forming step of depositing a correction film on a defect by introducing a source gas into a space of a protective film formed by the photomask and the protective film in a state where the protective film is attached to the photomask, and irradiating the defect with a laser beam through a protective film body provided in the protective film to cause a reaction of the source gas.

2. The method for correcting a photomask according to claim 1,

in the film forming step, the source gas is introduced from a protective film vent provided in a protective film frame of the protective film.

3. The method for correcting a photomask according to claim 2,

the protective film is held by a jig having an opening capable of being brought into close contact with the vent hole of the protective film,

in the film forming step, the raw material gas is introduced from the protective film vent through the opening.

4. The method for correcting a photomask according to any one of claims 1 to 3,

the film forming method further includes a gas replacement step of introducing a replacement gas into the protective film space to discharge the raw material gas from the protective film space.

5. The method for correcting a photomask according to any one of claims 1 to 3,

in the film forming step, the photomask is heated.

6. A method for manufacturing a photomask with a protective film, wherein,

the method for manufacturing the photomask with the protective film comprises the following steps: a method of correcting a defect in a transfer pattern formed on a photomask, using the photomask according to any one of claims 1 to 5.

7. A method for manufacturing a display device includes the steps of:

preparing a photomask with a protective film manufactured by the manufacturing method according to claim 6; and

the photomask with the protective film is exposed by an exposure device, and a transfer pattern is transferred to a transfer object.

8. A correction device for a photomask for correcting a defect generated in a transfer pattern of the photomask having the transfer pattern on a main surface of a transparent substrate, the correction device for the photomask comprising:

a mask holder for holding the photomask in a state in which a protective film is stuck on the main surface;

a gas introduction pipe for introducing a raw material gas into a protective film space formed by the photomask and the protective film;

a laser irradiation unit that irradiates a laser beam to the defective portion through the protective film body of the protective film;

a laser horizontal moving unit that moves the laser irradiation unit in an XY plane; and

a control unit which controls the laser horizontal moving unit.

9. The apparatus for correcting a photomask according to claim 8,

the apparatus for correcting a photomask further comprises a jig having a pair of hollow arms,

at least one of the pair of arms has an opening connected to the gas introduction pipe and capable of being brought into close contact with a protective film vent provided in a protective film frame provided in the protective film,

the clamp clamps the protective film frame by the pair of arms so that the opening part is closely attached to the protective film vent.

10. The apparatus for correcting a photomask according to claim 8 or 9,

the apparatus further includes a gas discharge pipe for discharging the remaining raw material gas from the protective film space.

11. The apparatus for correcting a photomask according to claim 8 or 9,

the apparatus for correcting a photomask further includes a heater for heating the photomask.

Technical Field

The present invention relates to a method and apparatus for correcting a photomask, a method for manufacturing a photomask with a protective film, and a method for manufacturing a display device.

Background

As a method for manufacturing a photomask, a method is known in which a pattern for transfer is formed by applying photolithography to a photomask substrate having at least 1 thin film formed on a transparent substrate. In recent years, there is a trend toward miniaturization of the pattern size of a photomask for a display device. On the other hand, in the process of manufacturing a photomask, it is difficult to completely avoid defects in a transfer pattern due to incomplete pattern formation of a thin film, adhesion of foreign matter, and the like.

Conventionally, as a method for correcting defects in a photomask, a laser CVD (Chemical vapor deposition) method is known (see patent document 1). In order to prevent foreign matter from adhering to the completed photomask, a member called a protective film (Pellicle) may be attached to the surface of the photomask on which the transfer pattern is formed, as necessary. This protective film is described in patent document 2, for example.

Patent document 1: japanese laid-open patent publication No. 2-140744

Patent document 2: japanese laid-open patent publication No. 9-68792

Disclosure of Invention

However, neither of patent documents 1 and 2 discloses a method for correcting a defect of a photomask to which a protective film is attached. In the case where correction is required after the protective film is attached, the protective film needs to be removed from the photomask to be corrected, and a new protective film is attached to the photomask after the correction is completed. Therefore, reduction in productivity and increase in cost become problems.

Accordingly, an object of the present invention is to provide a method for correcting a photomask, which can correct a defect in a transfer pattern without removing a protective film from the photomask.

The invention also provides a correction device for a photomask, a method for manufacturing a photomask with a protective film, and a method for manufacturing a display device.

(1 st mode)

According to the 1 st aspect of the present invention, there is provided a method of correcting a defect generated in a transfer pattern of a photomask having the transfer pattern on a main surface of a transparent substrate, the method comprising a film formation step of introducing a source gas into a protective film space formed by the photomask and a protective film in a state where the protective film is attached to the photomask, and irradiating a defect portion with a laser beam through a protective film body of the protective film to react the source gas, thereby depositing a correction film on the defect portion.

(2 nd mode)

According to a 2 nd aspect of the present invention, there is provided the method for correcting a photomask according to the 1 st aspect, wherein,

in the film forming step, the source gas is introduced from a protective film vent provided in a protective film frame of the protective film.

(3 rd mode)

According to the 3 rd mode of the present invention,

there is provided the method for correcting a photomask according to claim 2, wherein the protective film is held by a jig having an opening portion capable of being brought into close contact with the vent hole of the protective film,

in the film forming step, the raw material gas is introduced from the protective film vent through the opening.

(4 th mode)

According to the 4 th aspect of the present invention, there is provided the method for correcting a photomask according to any one of the 1 st to 3 rd aspects, wherein,

the film forming method further includes a gas replacement step of introducing a replacement gas into the protective film space to discharge the raw material gas from the protective film space.

(5 th mode)

According to the 5 th aspect of the present invention, there is provided the method for correcting a photomask according to any one of the 1 st to 4 th aspects,

wherein, in the film forming step, the photomask is heated.

(mode 6)

According to the 6 th aspect of the present invention, there is provided a method for manufacturing a photomask with a protective film, wherein,

the method for correcting a photomask according to any one of claims 1 to 5 is used to correct a defect in a transfer pattern formed on the photomask.

(7 th mode)

According to the 7 th aspect of the present invention, there is provided a method for manufacturing a display device, comprising the steps of:

preparing a photomask with a protective film manufactured by the manufacturing method according to claim 6; and

the photomask with the protective film is exposed by an exposure device, and a transfer pattern is transferred to a transfer object.

(8 th mode)

According to the 8 th aspect of the present invention, there is provided a correction device for a photomask for correcting a defect generated in a transfer pattern of a photomask having the transfer pattern on a main surface of a transparent substrate, the correction device for a photomask comprising:

a mask holder for holding the photomask in a state in which a protective film is stuck on the main surface;

a gas introduction pipe for introducing a raw material gas into a protective film space formed by the photomask and the protective film;

a laser irradiation unit that irradiates a laser beam to the defective portion through the protective film body of the protective film;

a laser horizontal moving unit that moves the laser irradiation unit in an XY plane; and

a control unit which controls the laser horizontal moving unit.

(9 th mode)

According to a 9 th aspect of the present invention, there is provided the apparatus for correcting a photomask according to the 8 th aspect, wherein,

the apparatus for correcting a photomask further comprises a jig having a pair of hollow arms,

at least one of the pair of arms has an opening connected to the gas introduction pipe and capable of being brought into close contact with a protective film vent provided in a protective film frame provided in the protective film,

the clamp clamps the protective film frame by the pair of arms so that the opening part is closely attached to the protective film vent.

(10 th mode)

According to a 10 th aspect of the present invention, there is provided the apparatus for correcting a photomask according to the 8 th or 9 th aspect, wherein,

the apparatus further includes a gas discharge pipe for discharging the remaining raw material gas from the protective film space.

(11 th mode)

According to an 11 th aspect of the present invention, there is provided the apparatus for correcting a photomask according to any one of the 8 th to the 10 th aspects, wherein,

the apparatus for correcting a photomask further includes a heater for heating the photomask.

According to the present invention, it is possible to provide a method for correcting a photomask, a device for correcting a photomask, a method for manufacturing a photomask with a protective film, and a method for manufacturing a display device, which can correct defects of the photomask without detaching the protective film from the photomask.

Drawings

Fig. 1 is an explanatory view showing an outline of a method of correcting a photomask according to an embodiment of the present invention, fig. 1 (a) is a schematic view showing a state where a defect portion is irradiated with a laser beam, and fig. 1 (b) is a schematic view showing a state where a correction film is deposited on the defect portion after the irradiation with the laser beam.

Fig. 2 is a schematic diagram showing a state in which a protective film frame (Pellicle frame) is sandwiched by arms of the correction device for a photomask according to the embodiment of the present invention.

Fig. 3 is a schematic configuration diagram illustrating a photomask correction apparatus according to an embodiment of the present invention.

Description of the reference symbols

1: photomask: 1 a: transparent substrate: 1 b: pattern for transfer printing: 2: protecting the film: 2 a: protecting the film body: 2 b: protecting the film frame: 3: and (4) protecting a vent hole of the film: 4: defect part: 5: protective film space: 6: and (3) correcting the film: 7: a clamp: 8: a laser oscillator: 9: laser: 10: opening part: 15: mask holder: 20: a gas introduction pipe: 30: laser horizontal movement portion: 35: upper XYZ robot control: 40: a control unit: 100: and a correction device.

Detailed Description

First, defects of the photomask, the protective film, and the transfer pattern according to the present embodiment will be described.

<1. examples of defects in photomask, protective film, and transfer pattern >

An example of defects in a photomask, a protective film, and a transfer pattern according to an embodiment of the present invention will be described.

(photo mask)

As shown in fig. 1, the photomask 1 of the present embodiment forms a transfer pattern 1b by patterning at least 1 thin film on a transparent substrate 1 a. For example, the photomask 1 can be obtained by applying Photolithography (Photolithography) to a photomask substrate having a thin film such as a light-shielding film formed on one main surface of the transparent substrate 1a to form the transfer pattern 1 b.

Specifically, the photomask 1 is manufactured by the method described below.

First, a photomask blank having a thin film formed on a transparent substrate 1a is prepared. Next, the thin film is patterned (patterning) to form a transfer pattern 1 b. Patterning of the thin film may be performed as many times as necessary. A protective film 2 is attached to the main surface on which the completed transfer pattern 1b is formed. Next, the transfer pattern 1b is inspected for defects using an inspection apparatus. When a defect is found, the defect is corrected by using the method for correcting a photomask of the present invention. As described above, the photomask with the protective film was completed.

(protective film)

As shown in fig. 1, a rectangular protective film 2 is attached to a main surface of a transparent substrate constituting a photomask 1. By attaching the protective film 2 to the main surface, it is possible to suppress foreign matter from adhering to the transfer pattern 1 b. In the present specification, the surface on which the transfer pattern 1b is formed, of the 2 main surfaces of the transparent substrate constituting the photomask 1, is referred to as a "main surface", and the other main surface is referred to as a "back surface".

The protective film 2 has a protective film frame 2b and a protective film body 2 a. The protective film 2 can be fixed by attaching the protective film frame 2b to the vicinity of the outer edge of 4 sides of the main surface of the photomask 1. As shown in fig. 2, the protective film frame 2b is formed in a quadrangular frame shape with 4 side portions. Although not shown in detail, each of the 4 side portions has a lower end surface that contacts the main surface of the photomask 1 via an adhesive or the like, an upper end surface that faces the lower end surface, an outer peripheral surface that connects the lower end surface and the upper end surface, and an inner peripheral surface that faces the outer peripheral surface. The inner peripheral surface is located inside the protective film frame 2 b. In addition, as the protective film body 2a, a known protective film body can be used as a photomask for manufacturing a display device.

As shown in fig. 2, a plurality of vent holes 3 (hereinafter, also referred to as "protective film vent holes 3") are provided at predetermined intervals in the protective film frame 2b, and the vent holes 3 can adjust the difference in air pressure between the inside and the outside of the protective film 2. The vent 3 penetrates from the outer peripheral surface to the inner peripheral surface of the protective film frame 2 b. Here, 2 protective film vents 3 are provided in 2 side portions of the protective film frame 2b facing each other, but this is merely an example, and the number and arrangement of the protective film vents 3 are arbitrary.

(Defect of transfer Pattern)

The defects of the transfer pattern 1b of the photomask 1 include a black defect having a light transmittance lower than an allowable value and a white defect having a light transmittance higher than an allowable value. The black defect is a defect caused by a film remaining in an unnecessary portion, adhesion of a foreign substance, or the like. The white defect is a defect generated due to a defect of a necessary thin film or the like, and is generated, for example, when a thin film on the transparent substrate 1a is patterned (see fig. 1 (a)).

Next, a method for correcting a photomask according to the present invention will be described with reference to the drawings.

<2 > example of method for correcting photomask

An example of a method for correcting a photomask according to an embodiment of the present invention will be described.

Fig. 1 is an explanatory diagram illustrating an outline of a method of correcting a photomask 1 according to the present embodiment.

The defective portion 4 of the transfer pattern 1b formed on the photomask 1 to which the protective film 2 is attached according to the present embodiment can be corrected by performing a film formation step in which a source gas is introduced into the protective film space 5 (see fig. 1 a), and the defective portion 4 is irradiated with the laser beam 9 through the protective film body 2a to deposit the correction film 6 on the defective portion 4 (see fig. 1 b).

The film forming process will be described below with reference to the drawings. The defective portion 4 is an area where a defect is generated. The protective film space 5 is a space formed by the photomask 1 and the protective film 2 (i.e., a space surrounded by the main surface of the photomask, the protective film frame 2b, and the protective film body 2 a).

(film Forming Process)

First, as shown in fig. 1 (a), a source gas for forming the correction film 6 is introduced into the protective film space 5 from the protective film vent 3. Thus, the vicinity of the transfer pattern 1b where the white defect occurs becomes an atmosphere of the raw material gas. The introduction of the source gas into the resist space 5 is indicated by the black arrows on the right side of fig. 1 (a). Further, the raw material gas will be described later.

Next, as shown in fig. 1 (a), the defect 4 is irradiated with a laser beam 9 of a predetermined wavelength from the laser oscillator 8 through the protective film body 2a while the defect 4 is in the source gas atmosphere. At this time, the laser beam 9 is irradiated while being focused on the defective portion 4 of the transfer pattern 1b, and the correction film 6 formed by the reaction of the raw material gas is deposited on the defective portion 4 as shown in fig. 1 (b). Further, the laser light 9 is in a defocused state at the position of the protective film body 2a, and therefore, damage of the protective film body 2a does not substantially occur.

By continuing the introduction of the source gas for a predetermined time, a part of the gas (including the source gas) filled in the protective film space 5 is discharged from the other protective film vent 3. This can suppress the atmospheric pressure in the protective film space 5 from exceeding the atmospheric pressure outside the protective film space.

Further, in order to promote the discharge of the gas and suppress the discharged raw material gas from staying in the vicinity of the outlet of the protective film vent port 3, the gas may be introduced from the outside of the other protective film vent port 3.

In the film formation step, in order to reduce the risk of deposition of the source gas on unnecessary portions, it is preferable that the source gas near the main surface is indirectly heated by heating the photomask 1 with a heater 75 disposed on the back surface of the photomask 1.

After the correction of the defect of the transfer pattern 1b is completed, the excess raw material gas can be discharged through the protective film vent 3. For example, 1 or more of the protective film vents 3 may be used for introducing the raw material gas, and the other protective film vents 3 may be used for exhausting the gas. Here, the excess source gas refers to a gas that does not contribute to the formation of the correction film 6 among the source gases present in the protective film space 5. For example, by introducing a replacement gas described later into the protective film space 5, the excess raw material gas can be discharged from the protective film space 5.

Next, a correction apparatus for a photomask according to the present invention will be described with reference to the drawings.

<3. structural example of correction apparatus for photomask >

A configuration example of a correction apparatus for a photomask according to an embodiment of the present invention will be described.

Fig. 3 is a schematic configuration diagram illustrating the photomask correction apparatus 100 according to the present embodiment.

(Overall Structure)

As described with reference to fig. 1, the photomask correction apparatus 100 exemplified in the present embodiment is configured to form the correction film 6 on the defective portion 4 by processing the photomask 1 to which the protective film 2 is attached by using the laser CVD method, and thereby correct the defect generated in the transfer pattern 1b without detaching the protective film 2 from the photomask 1.

The photomask correction apparatus 100 mainly includes a mask holder 15, a jig 7, a gas introduction pipe 20, a laser oscillator (laser irradiation unit) 8, a laser horizontal movement unit (laser horizontal movement unit) 30, and an upper XYZ robot control unit (control unit) 35.

(mask holder)

The mask holder 15 holds the photomask 1 to which the protective film 2 is attached. The photomask 1 on the mask holding frame 15 is held substantially horizontally with the main surface thereof being on. Substantially horizontal includes the case where there is slight flexure of photomask 1. Further, the size of the mask holding frame 15 is appropriately selected according to the size of the photomask 1.

(Clamp)

The jig 7 holds the protective film frame 2 b. The jig 7 has: a pair of arms 7a (details will be described later) for holding the protective film frame 2 b; and a connecting portion 7b connecting the arms. In fig. 3, the pair of coupling portions 7b is shown as an example, but the number of coupling portions is not limited. The "sandwiching" includes not only a mode in which the pair of arms 7a are in contact with (closely attached to) the protective film frame 2b, but also a mode in which the pair of arms 7a are arranged so as to sandwich the protective film frame 2b with a slight space provided between one of the pair of arms 7a and the protective film frame 2b (that is, one of the pair of arms 7a is not in contact with the protective film frame 2 b). Although details will be described later, one of the pair of arms 7a can be used for introducing the source gas and the other can be used for exhausting the source gas. For example, the following method can be selected: the gas is introduced into the protective film space 5 by bringing one arm 7a into close contact with the protective film frame 2b, and when the gas in the protective film space 5 is discharged, the other arm 7a is selected to be brought into contact with the protective film frame 2 b. In the case of non-contact, the other arm 7a may be disposed at a position where the gas can be sucked from an opening 10, which will be described later, provided in the other arm 7a so that the gas discharged from the protective film space 5 does not stagnate near the outlet of the protective film vent 3.

(arm)

The arm 7a is hollow so as to pass the raw material gas. In order to introduce the raw material gas, discharge the excess raw material gas, and the like, the arm 7a is provided with a plurality of openings 10 corresponding to the protective film vent 3. The structure of the inside of the arm 7a is not particularly limited as long as it is hollow so that the raw material gas can pass through. For example, a ventilation channel (not shown) may be provided inside the arm 7a, and the ventilation channel may communicate with the gas introduction pipe 20 and the opening 10.

The jig 7 can bring the opening 10 into close contact with the protective film vent hole 3 by sandwiching the protective film frame 2b from 2 outer circumferential surfaces provided with the protective film vent hole 3 by a pair of arms 7 a. Thereby, the raw material gas can be introduced into the protective film space 5 through the opening 10 from the protective film vent 3. As a sensor for detecting the state of clamping the protective film frame 2b by the arm 7a, a Limit switch (Limit switch) may be provided in the arm 7 a.

When the protective film frame 2b is sandwiched between the pair of arms 7a, the opening 10 is preferably larger than the protective film vent 3 because the position of the opening 10 may be slightly displaced from the position of the protective film vent 3. For example, the longitudinal and transverse inner diameters of the opening 10 may be larger than the outer edge of the protective film vent 3 by about 1 to 2 mm. Thus, even if the position of the opening 10 is slightly displaced from the position of the protective film vent 3, the outer edge of the protective film vent 3 can be accommodated in the opening 10.

In addition, in order to suppress formation of an unnecessary film from the raw material gas, it is preferable to heat the arm 7 a. The heating method is not particularly limited, and a known heating method such as a heater can be used.

The arm 7a is movable along the connection portion 7b in the X direction or the Y direction (in fig. 3, the Y direction) by a movement mechanism (not shown). This enables the jig 7 to hold protective films of various sizes. The movement of the arm 7a in the X direction or the Y direction is controlled by a jig movement control unit (not shown) that controls the movement mechanism. The jig movement control section may be controlled by the control unit 40.

In the present embodiment, the following is also included: a plane having a substantially constant distance from the main surface of the photomask 1 is a plane parallel to the main surface, and the main surface is deflected. When it is assumed that the main surface of the photomask 1 is not warped, a plane parallel to the main surface is an XY plane, a direction parallel to a long side or a short side of the main surface is an X direction, and a direction perpendicular to the X direction in the XY plane is a Y direction. The Z direction is defined as a direction perpendicular to the X direction and the Y direction.

(gas inlet pipe)

The gas introduction pipe 20 is connected to the arm 7a of the jig 7, and is configured to introduce the source gas supplied from the source tank 70 into the protective film space 5. In fig. 3, 1 gas introduction pipe 20 is illustrated, but the number of gas introduction pipes may be plural. The opening 10 provided in the arm 7a of the jig 7 can be connected to the gas introduction pipe 20 directly or indirectly via another member. Therefore, the source gas is introduced into the protective film space 5 from the protective film vent port 3 through the gas introduction pipe 20 and through the opening 10 of the arm 7a of the jig 7.

The gas introduction system for introducing the source gas into the protective film space 5 includes a source tank 70 and a carrier gas supply pipe (not shown) in addition to the gas introduction pipe 20.

(Carrier gas supply pipe)

The carrier gas supply pipe supplies a carrier gas (e.g., argon) composed of an inert gas to the raw material tank 70.

(raw material case)

The raw material tank 70 is used to generate a raw material gas by mixing a raw material for forming the correction film 6, which is vaporized by heating and sublimation, with a carrier gas.

The source tank 70 can be connected to a gas control unit 65, which will be described later, for example, and the source gas can be supplied from the source tank 70 to the gas introduction pipe 20 under the control of the gas control unit 65. The source gas is introduced into the protective film space 5 through the gas introduction pipe 20 from any one of the protective film vents 3. The gas introduction pipe 20 may be covered with a heat insulating material to prevent the raw material gas passing through the gas introduction pipe 20 from being cooled by the outside air to form an unnecessary film. The source tank 70 and the carrier gas supply pipe are not necessarily provided in the correction apparatus 100, and may be provided separately from the correction apparatus 100.

(raw gas)

As described in fig. 1, the source gas is decomposed by the photo CVD reaction by the irradiated laser beam 9, and the correction film 6 can be deposited on the defect site 4. As the raw material gas, metal carbonyl (Metalcarbonyl) is preferably used. Specifically, chromium carbonyl (Cr (CO))₆) Molybdenum carbonyl (Mo (CO))₆) Tungsten carbonyl (W (CO))₆) And the like. Chromium carbonyls are particularly preferred because of their high resistance to chemicals.

(laser oscillator)

The laser oscillator 8 irradiates the transfer pattern 1b with laser light 9, is disposed above the protective film body 2a, and is configured to be movable relative to the photomask 1 in the XY plane. The laser oscillator 8 is configured to be movable in the Z direction relative to the photomask 1, so that the laser beam 9 can be adjusted and focused on the defective portion 4 even if the photomask 1 is flexed. With such a configuration, the laser oscillator 8 can reach an arbitrary position above the transfer pattern 1b and irradiate the laser beam 9 while focusing on the defective portion 4. The relative movement indicates that one of the photomask 1 and the laser oscillator 8 is moved while the other is stationary, or both are moved.

The irradiated laser light 9 causes a photo CVD reaction at the defect site 4 which becomes the raw material gas atmosphere. This enables the correction film 6 to be deposited on the defective portion 4. According to the correction apparatus 100, the correction film 6 can be formed to have a film thicknessIn addition, the size of the correctable white defect can be about 0.3 to 50 μm.

The irradiation of the laser beam 9 is controlled by a laser control unit (not shown), and the laser control unit is controlled by the control unit 40. The wavelength λ of the laser light 9 to be used may be selected as appropriate according to the type of the source gas, the material of the transparent substrate 1a of the photomask 1, the material of the protective film 2a, and the like. The wavelength λ of the laser light 9 is preferably 200nm to 600nm, more preferably 265nm to 530 nm. By using these wavelengths, the correction film 6 can be deposited on the defective portion 4 with higher accuracy.

(laser horizontal moving part)

The laser horizontal movement unit 30 moves the laser oscillator 8 in the XY plane. The laser horizontal movement unit 30 includes an upper X robot 30a and an upper Y robot 30 b.

(control section)

The upper XYZ robot controller 35 as a controller controls the laser beam horizontal transfer unit 30.

The correction device 100 also has a laser displacement meter 45.

(laser displacement meter)

The laser displacement meter 45 detects the position of the photomask 1 on the mask holding frame 15. The laser displacement meter 45 is provided above the photomask and is configured to be movable in the XY plane and in the Z direction. The laser displacement meter 45 can detect the height of the main surface with respect to the surface of the mask holder 15 by emitting inspection light in the Z direction with respect to the photomask 1 on the mask holder 15 and detecting reflected light. This enables detection of the position of the photomask 1 on the mask holder 15.

The correction device 100 also has a gas discharge pipe 50.

(gas discharge pipe)

The gas discharge pipe 50 is for discharging the remaining raw material gas remaining in the protective film space 5 after the completion of the correction. In fig. 3, 1 gas discharge pipe 50 is illustrated, but the number of gas discharge pipes may be plural. The gas discharge pipe 50 can be connected to 1 or more of the openings 10 provided in the arm 7a of the jig 7 directly or indirectly via another member. Thereby, the excess raw material gas is discharged through the 1 or more openings 10. In order to efficiently perform the exhaust, for example, a ventilation passage may be provided inside the arm 7a, and the ventilation passage may communicate with the gas discharge pipe 50 and the opening 10.

In order to prevent the raw material gas discharged from the protective film space 5 from staying in the vicinity of the outlet of the protective film vent 3, it is preferable to supply air from the opening 10. In this case, the air outside the protective film space can be also sucked at the same time so that the air pressure inside the protective film space 5 is not excessively smaller than the air pressure outside the protective film space due to the excessive intake air. For example, an air hole may be provided in the vicinity of the opening 10 for air intake, and the air hole may be used for sucking air outside the protective film space.

By introducing the replacement gas stored in the replacement gas tank (not shown) into the protective film space 5, the excess raw material gas can be discharged. The replacement gas tank may be provided in the correction device 100 or may be provided separately. Examples of the substitution gas include an inert gas such as nitrogen and a dry gas.

Like the raw material gas, the replacement gas is introduced into the protective film space 5 through the gas introduction pipe 20 from the one or more protective film vents 3 in close contact with the opening 10 of the jig 7. The replacement gas may be introduced to push the excess raw material gas out of the other protective film vent 3 and discharge the excess raw material gas through 1 or more openings 10 connected to the gas discharge pipe 50. Thus, the source gas in the film protection space 5 is replaced with the replacement gas.

The introduction and discharge of the raw material gas and the substitution gas may be controlled by the gas controller 65. The raw material gas and the substitution gas may be introduced through a common gas introduction pipe or through different gas introduction pipes. When a common gas introduction pipe is used, the connection between the source gas tank and the gas introduction pipe and the connection between the replacement gas tank and the gas introduction pipe can be switched by the gas control unit 65. The gas control section 65 is controlled by the control unit 40.

The correction device 100 further includes an observation optical system 55 and an observation illumination 60.

(optical System for Observation, Lighting for Observation)

The observation optical system 55 and the observation illumination 60 are used to enable observation of an arbitrary position on the photomask 1. The observation optical system 55 and the observation illuminator 60 can be disposed at positions facing each other with the photomask 1 placed on the mask holder 15 placed therebetween. The correction device 100 can observe the position, shape, and the like of the defect and irradiate the laser beam 9 with the observation optical system 55 and the observation illumination 60, and thus can correct the defect with higher accuracy. Further, the observation optical system 55 and the observation illumination 60 can be preferably moved in synchronization with the movement of the laser oscillator 8 by the control of an observation optical system control unit (not shown).

Preferably, the laser oscillator 8 and the observation optical system 55 are movable relative to the photomask 1 placed on the mask holder 15 in a direction (Z direction) perpendicular to the main surface of the photomask 1. Thus, even if the photomask 1 is warped, the laser beam 9 can reach the focus position suitable for the main surface. That is, the laser oscillator 8 can move in the Z direction so that focus adjustment can be performed with respect to the defective portion 4.

Preferably, the laser oscillator 8 and the observation optical system 55 are movable in the XY plane and in the Z direction. Therefore, the photomask correction apparatus 100 of the present embodiment preferably includes an upper X robot 30a and an upper Y robot 30b that move the laser oscillator 8 and the observation optical system 55 in the XY plane, and an upper Z robot 30c that moves the laser oscillator 8 and the observation optical system 55 in the Z direction. The upper X robot 30a, the upper Y robot 30b, and the upper Z robot 30c are controlled by an upper XYZ robot controller 35. The upper XYZ robot controller 35 is controlled by the control unit 40.

Further, it is preferable that the observation illumination 60 is also movable in the XY plane and in the Z direction so as to be synchronized with the movements of the laser oscillator 8 and the observation optical system 55. Therefore, the correction device 100 preferably includes the lower X robot 80 and the lower Y robot 85 that move the observation illumination 60 in the XY plane, and the lower Z robot 90 that moves the observation illumination 60 in the Z direction. In addition, it is preferable that the positions in the X direction and the Y direction of the observation illumination 60 coincide with the positions in the X direction and the Y direction of the observation optical system 55. The lower X robot 80, the lower Y robot 85, and the lower Z robot 90 are controlled by a lower XYZ robot controller (not shown). The lower XYZ robot is controlled by the control unit 40.

In order to suppress the formation of an unnecessary film on the main surface of the photomask 1 from the raw material gas, the raw material gas is preferably heated. The heating means of the raw material gas is not particularly limited, but the correction device 100 may have a heater 75 as heating means, for example. For example, by heating the photomask 1 by using the heater 75, the raw material gas in the protective film space 5 can be indirectly heated, and formation of an unnecessary film on the main surface can be suppressed. The raw material gas in the protective film space 5 is preferably heated to 40 ℃ or higher, and more preferably heated to 40 to 50 ℃.

The position of the heater 75 is not particularly limited if the source gas in the protective film space 5 can be uniformly heated, but the heater 75 can be disposed on the back surface side of the photomask 1, for example. As the heater 75, a heat-resistant glass substrate transparent to visible light can be used. Specifically, a transparent glass heater having a transparent conductive film and an electrode is given.

By using the glass substrate as described above, the photomask 1 can be uniformly heated. Further, since the gas flow is less likely to occur during heating using the glass substrate, it is also possible to suppress adhesion of foreign matter to the photomask 1.

<4 > effects of the present embodiment

According to the present embodiment, one or more effects described below are achieved.

(a) According to the method and apparatus 100 for correcting a photomask of the present embodiment, the defective portion 4 of the photomask 1 can be corrected by the protective film body 2 a. Thus, even when correction of a white defect is required after the protective film 2 is attached, the white defect can be corrected without detaching the protective film 2. Therefore, in the correction performed after the protective film 2 is attached, the step of removing the protective film 2 can be eliminated, and the photomask 1 (photomask with a protective film) can be quickly corrected and shipped. In addition, since it is not necessary to attach a new protective film after the correction, the cost can be reduced.

(b) According to the method and apparatus 100 for correcting a photomask of the present embodiment, since a defect can be corrected in a state where the photomask 1 is left in the atmosphere, a simple operation can be realized.

(c) According to the method and apparatus 100 for correcting a photomask of the present embodiment, for example, a photomask using a light-shielding film or a semi-light-transmitting film as a thin film formed on the transparent substrate 1a can be corrected. Further, the photomask transferred by projection exposure can be corrected. In the present embodiment, although correction of the photomask is described as an example in which the photomask is not exposed (before being used for transfer to the transfer target), correction of the photomask may be performed after exposure (after being used for transfer to the transfer target).

<5. use of photomask >

The use of the photomask is not limited. However, the apparatus 100 and method for correcting a photomask according to the present embodiment can be preferably applied to correction of defects generated in a photomask (photomask with a protective film) particularly used for manufacturing a Flat Panel Display (FPD).

For example, a photomask for manufacturing a display device such as an LCD (liquid crystal display device) or an OLED (organic EL display device) is exemplified. For example, a photomask for such applications has a main surface in the shape of a rectangle having one side of 300 to 2000mm, and the specific dimensions vary depending on the specifications of a target flat plate. The display device manufacturing includes manufacturing of a device for a display device mounted on a display device. The exposure apparatus includes an optical system for a display device manufactured by an exposure apparatus, which applies projection exposure and has an NA (numerical aperture) of about 0.08 to 0.15. As the light source for exposure, any wavelength in the range of i-line to g-line can be used, and in particular, it is advantageous to use light including this wavelength band as the exposure light source.

The photomask for the above-mentioned application includes a photomask having a size of about 1 to 300 μm, and is often used as a pattern width (CD: Critical Dimension) of the transfer pattern 1 b. When such a pattern has a white defect, if the correction method of the present embodiment is applied, correction can be performed more efficiently and more precisely.

<6. example of processing operation in photomask correction apparatus >

Next, an example of processing operation in the photomask correction apparatus 100 having the above-described configuration will be described.

In the defect correction using the correction apparatus 100 of the present embodiment, a set (set) step, a position detection step, a coordinate axis determination step, a connection step, a film formation step, and a gas replacement step, which will be described later, are performed in this order. In the following description, the operations of the respective components constituting the correction device 100 are mainly controlled by the control unit 40.

(setting step)

In the setting step, a photomask 1 having a protective film 2 attached to its main surface is prepared, and the photomask 1 is set in a mask holder 15. Then, the mask holder 15 is moved into the correction apparatus 100.

(position detection step)

When the mask holder 15 is moved, the position of the photomask 1 on the mask holder 15 may be displaced. Therefore, in the position detection step, the height of the main surface is measured by the laser displacement meter 45 disposed above the photomask 1 to obtain data including the distribution of the height of the main surface, and the position of the photomask 1 on the mask holder 15 is detected using the data.

(coordinate axis specifying step)

In the coordinate axis determining step, alignment marks and the like formed near the outer periphery of the photomask 1 are read to grasp the approximate arrangement direction of the transfer pattern 1 b. Then, by reading the transfer pattern 1b, the arrangement direction of the transfer pattern 1b is grasped delicately, and the coordinate axis of the transfer pattern is specified. By determining the coordinate axes, determination of the defect positions can be performed as described later. The alignment mark indicates a pattern formed for alignment of the transfer pattern 1 b.

(joining Process)

In the connection step, the protective film frame 2b is sandwiched between the pair of arms 7a of the jig 7, and the opening 10 of the jig 7 connected to the gas introduction pipe 20 is brought into close contact with and connected to the protective film vent hole 3. By providing the arm 7a of the jig 7 with the opening 10 corresponding to the protective film vent port 3, the protective film vent port 3 can be reliably brought into close contact with the opening 10 of the arm 7a, and the work efficiency of introducing the raw material gas can be improved.

(film Forming Process)

In the film formation step, first, a source gas is introduced into the protective film space 5 formed by the photomask 1 and the protective film 2. The raw material gas is introduced through the gas introduction pipe 20 from the one or more protective film vents 3 in close contact with the opening 10.

Preferably, when the source gas is introduced, the gas is adjusted to be discharged from 1 or more of the other protective film vents 3 so that the gas pressure in the protective film space 5 does not greatly exceed the gas pressure outside the protective film space. This can suppress the expansion of the protective film body 2 a. This exhaust is continued until the gas replacement step described later is completed.

Further, the gas may be introduced from the opening 10 to suppress the discharged raw material gas from staying in the vicinity of the outlet of the protective film vent 3. In this case, as described above, air outside the protective film space may be simultaneously sucked by providing an air hole or the like near the opening 10 for air intake so that the air pressure inside the protective film space 5 is not excessively lower than the air pressure outside the protective film space due to excessive air intake.

In order to prevent the formation of an unnecessary film on the main surface by the source gas, the source gas in the protective film space 5 is heated until the gas replacement step described later is completed.

After the transfer pattern 1b is formed, the photomask 1 is inspected for defects by an inspection apparatus, and the position (coordinates) of the defective portion 4 is grasped in advance. In order to match the coordinates in the inspection device with the coordinates in the correction device 100, the reference point in the inspection device and the reference point in the correction device 100 are matched to form the origin of the coordinates.

Next, the defect site 4 is irradiated with the laser beam 9 through the protective film body 2a to react the raw material gas, thereby depositing the correction film 6 on the defect site 4.

Specifically, the position coordinates of the defective portion 4 are acquired based on the coordinate axes obtained in the coordinate axis determining step and the origin, and the laser beam 9 is irradiated to the defective portion 4 through the protective film body 2 a.

The laser beam 9 causes the material gas to react, and the correction film 6 is deposited on the defect site 4. In this way, the defects of the photomask 1 are corrected. Further, a focusing step of adjusting the focal point of the laser beam 9 before the irradiation of the laser beam 9 may be included. In the focusing step, the laser beam 9 is adjusted to be focused on the defect site 4 to be corrected, and defocuses the protective film body 2 a.

(gas replacement step)

In the gas replacement step, after the film formation step, the excess raw material gas is replaced with another gas (replacement gas) in order to discharge the excess raw material gas in the protective film space 5. This can suppress the deposition of an unnecessary film on the main surface of the photomask 1.

By introducing the replacement gas into the protective film space 5 from one or more protective film vents 3, the excess gas is discharged from one or more other protective film vents 3 having openings 10 arranged in the vicinity thereof. Thereby, the raw material gas in the film protection space 5 is replaced with the replacement gas.

Similarly to the film forming step, the gas may be introduced through the opening 10 to prevent the surplus material gas discharged from staying in the vicinity of the outlet of the protective film vent 3.