JP2021139993A - Defect correction method for halftone mask, method for manufacturing halftone mask, and halftone mask - Google Patents

Abstract

To provide a defect correction method for a halftone mask allowing extremely accurate defect correction, a method for manufacturing a halftone mask, and a halftone mask in which defects are corrected with extremely high accuracy.SOLUTION: A defect correction method for a halftone mask according to the present invention is for correcting a defect 4 generated in a semi-transmissive portion 3 by forming a correction film 10 in a defect correction target region 5 of the semi-transmissive portion 3. The method comprises: a main film formation step for forming a main film 8 in the defect correction target region 5 so that the transmittance is equal to the transmittance of the semi-transmissive portion 3; and a fill film formation step for forming a fill film 9 in a highly transmissive portion remaining in the defect correction target region 5 even after the main film 8 is formed, so that the transmittance is equal to the transmittance of the semi-transmissive portion 3.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for correcting defects generated in a semitransparent portion of a halftone mask, a method for manufacturing a halftone mask to which this method is applied, and a halftone mask manufactured by applying this method.

A halftone mask is known as a photolithography technique. The halftone mask is provided with a semi-transmissive portion having a transmittance between the transmittance of the transmissive portion (also referred to as light transmissivity; the same shall apply hereinafter) and the transmissivity of the light-shielding portion, thereby providing a white floor due to the transmissive portion. Since it realizes multiple gradations (3 gradations or more) by combining 2 gradations of black gradation by the toning and shading part and the gradation of intermediate (gray tone) between white and black by the semi-transmissive part. Also called a multi-gradation photo mask. By using a halftone mask, it is possible to form patterns on the photoresist having different exposure amounts in one exposure. Therefore, it is possible to reduce the number of photomasks used, the manufacturing process, and the manufacturing cost.

Here, in the halftone mask, two defects can be roughly classified due to problems in the manufacturing process and the like. One is a defect that a defect exists in a part of the semi-transmissive portion (it is called a "white defect" because the transmittance increases when the defect exists). The other is a defect that a surplus or a foreign substance is present in a part of the semi-transmissive portion (it is called a "black defect" because the transmittance decreases when a foreign substance or the like is present). ..

When such a defect occurs, it is necessary to correct the defect. In the case of a white defect, the white defect is corrected by forming a correction film on the defective portion. In the case of a black defect, the black defect is corrected by removing a foreign matter or a semi-transmissive portion in which the foreign matter or the like is present and forming a new correction film as necessary.

As the defect correction method, the method described in Patent Document 1 and the method described in Patent Document 2 are known. In these methods, a correction film is formed by using a laser CVD (Chemical Vapor Deposition) method. That is, in these methods, the laser light emitted from the laser oscillator is passed through the aperture, focused by the objective lens, and irradiated to the surface of the defect correction target photomask placed in the reaction gas atmosphere. A modified film of a CVD film is formed. According to the laser CVD method, the film thickness of the correction film can be made uniform. This enables highly accurate defect correction.

Japanese Unexamined Patent Publication No. 2010-210919 Japanese Unexamined Patent Publication No. 2017-173670

However, in recent years, as the quality of products has been further improved, the demand for more accurate pattern formation has tended to increase. In the case of OLED (OLED: Organic Light Emitting Diode, also called organic EL (Organic Electro-Luminescence)) used for the panel of the next-generation display, the semi-transmissive part has a larger area than the liquid crystal panel. Also joins. Therefore, it is necessary to further improve the accuracy of defect correction.

Therefore, the present invention has been made in view of such circumstances, and is a method for correcting defects in a halftone mask, a method for manufacturing a halftone mask, and a method for correcting defects with extremely high accuracy, which enables extremely high-precision defect correction. It is an object of the present invention to provide a halftone mask.

The method for correcting defects in the halftone mask according to the present invention is as follows.
This is a method for correcting defects in a halftone mask by forming a correction film in a region to be corrected for defects in the semitransparent portion of the halftone mask to correct defects generated in the semitransparent portion.
A main film film forming step of forming a main film in the defect repair target area so that the transmittance is equal to the transmittance of the semi-transmissive portion.
A halftone mask provided with a compensating film film forming step of forming a compensating film so that the transmittance is equal to the transmissivity of the semi-transmissive part in the highly transmissive portion remaining in the defect correction target region even after the film formation of the main film. This is a defect correction method.

Here, as one aspect of the defect correction method of the halftone mask according to the present invention,
In the main film film forming step, the main film is formed in a shape that matches the defect correction target area, or a gap is formed between at least a part of the boundary of the defect correction target area and at least a part of the outer edge of the main film. To form a film on the main film.
In the compensation film film forming step, a filling film is formed on the boundary of the defect correction target area and the highly permeable portion formed along the outer edge of the main film in the width from the boundary of the defect correction target area to the outer edge of the main film. It is possible to adopt the configuration of being a thing.

Further, as another aspect of the defect correction method for the halftone mask according to the present invention,
The main film film formation process is
A base layer film forming process for forming a base layer having a transmittance higher than that of the semitransparent part, and
A configuration is adopted in which a transmittance adjusting layer film forming step of forming one or a plurality of transmittance adjusting layers on the base layer is provided so that the transmittance becomes equal to the transmittance of the semi-transmissive portion. be able to.

in this case,
In the base layer film forming step, the base layer is formed so that a gap is formed between the boundary of the defect correction target area and the outer edge of the base layer, or the outer edge of the base layer is formed at the boundary of the defect correction target area. It is possible to adopt a configuration in which the base layer is formed so that the base layers are in contact with each other.

Further, as another aspect of the defect correction method for the halftone mask according to the present invention,
The compensating film film forming step adopts a configuration including a transmittance adjusting layer film forming step of forming one or a plurality of transmittance adjusting layers so that the transmittance becomes equal to the transmittance of the semi-transmissive portion. can do.

Further, as yet another aspect of the defect correction method for the halftone mask according to the present invention,
Prior to the main film film formation step, a defect repair target region having a predetermined shape including the defect is set, and a trimming step for removing the existing semi-transmissive film existing in the defect repair target region is provided. Can be done.

Further, as yet another aspect of the defect correction method for the halftone mask according to the present invention,
When the defect exceeds a predetermined size, it is possible to adopt a configuration in which the defect correction target area is divided into a plurality of areas and the defect is corrected.

Further, as yet another aspect of the defect correction method for the halftone mask according to the present invention,
It is possible to adopt a configuration in which a correction film is formed by irradiating a laser beam in the defect correction target area in the atmosphere of the raw material gas.

Further, the method for manufacturing a halftone mask according to the present invention is as follows.
A process of forming a light-shielding portion, a transmissive portion, and a semi-transmissive portion on a transparent substrate,
It is equipped with a defect correction process that corrects defects that occur in the semi-transparent part.
This is a method for manufacturing a halftone mask to which any of the above defect repair methods is applied as a defect repair step.

Further, the halftone mask according to the present invention is
A light-shielding part, a transmissive part, and a semi-transparent part are provided on the transparent substrate.
By applying any of the above defect correction methods, it is a halftone mask provided with a correction film in the semi-transmissive part.

As described above, according to the present invention, the modified film is composed of a main film and a filling film, and these are individually adjusted in transmittance to form a film. As a result, the modified film is formed so that the transmittance is uniform over the entire surface and equal to the transmittance of the semi-transmissive portion. Therefore, according to the present invention, extremely high-precision defect correction can be realized.

FIG. 1A is a schematic view of a defect correction device used in the halftone mask defect correction method and the halftone mask manufacturing method according to the present embodiment. 1B and 1C are schematic views of a slit of the defect correction device. 2 (a) to 2 (f) are explanatory views of the defect correction method 1. 3 (a) to 3 (c) are explanatory views of the second step of the defect repair method 1, and are explanatory views of parts A and B of FIG. 2 (c). 4 (a) to 4 (d) are explanatory views of the third step of the defect repair method 1, and are explanatory views of parts C and D of FIG. 2 (d). 5 (a) to 5 (d) are explanatory views of the fourth step of the defect repair method 1, and are explanatory views of parts E and F of FIG. 2 (e). 6 (a) to 6 (e) are explanatory views of the defect repair method 2-1 from the first step to the fourth step. 7 (a) to 7 (e) are explanatory views from the fifth step to the ninth step of the defect repair method 2-1. 8 (a) to 8 (d) are explanatory views of the defect repair method 2-2 from the first step to the third step. 9 (a) to 9 (e) are explanatory views from the fourth step to the eighth step of the defect correction method 2-2. 10 (a) to 10 (c) are explanatory views from the first step to the second step of the defect repair method 2-3. 11 (a) to 11 (e) are explanatory views from the third step to the seventh step of the defect repair method 2-3. 12 (a) to 12 (f) are explanatory views of the defect correction method 2-4. 13 (a) to 13 (e) are explanatory views of the defect repair method 2-5 from the first step to the fourth step. 14 (a) to 14 (e) are explanatory views from the fifth step to the ninth step of the defect repair method 2-5. 15 (a) to 15 (d) are explanatory views of the defect correction method 3. 16 (a) to 16 (f) are explanatory views of the defect repair method 1 in the case of repairing a defect generated in the vicinity of the light-shielding portion.

Hereinafter, a method for correcting defects in a halftone mask, a method for manufacturing a halftone mask, and an embodiment of the halftone mask according to the present invention will be described with reference to the drawings.

<Defect correction device>
First, a defect correction device for performing defect correction will be described. As shown in FIG. 1A, the defect correction device is a device for forming a correction film (CVD film) by using a laser CVD method. The defect correction device mainly includes a laser optical system 20, a laser optical system 30, an optical system 40, a gas supply system 50, and a position control system 60.

The laser optical system 20 is a laser optical system for forming a correction film. The laser optical system 20 includes a laser oscillator (CVD Laser) 21, a collimating lens 22, a beam expander 23, an attenuator 24, and a beam scan unit 25. The laser beam (laser beam) emitted from the laser oscillator 21 is parallelized by the collimating lens 22, the beam diameter is expanded by the beam expander 23, adjusted to an appropriate output by the attenuator 24, and then the beam scan unit. Scanned by 25.

The laser optical system 30 is a laser optical system for partially removing the semi-transmissive film constituting the semi-transmissive portion. The laser optical system 30 includes a laser oscillator (Zap Laser) 31, a collimating lens 32, a beam expander 33, and an attenuator 34. The laser beam (laser beam) emitted in a pulse shape from the laser oscillator 31 is made parallel by the collimating lens 32, the beam diameter is expanded by the beam expander 33, and the output is adjusted to an appropriate level by the attenuator 34.

The optical system 40 is for guiding the laser light emitted from the laser optical systems 20 and 30 to the surface of the halftone mask 11. The optical system 40 includes a prism 41, a prism 42, a slit 43, a prism 44, a prism 45, and an objective lens 46. The prism 41 reflects the laser beam emitted from the laser optical system 20. The prism 42 transmits the laser light reflected by the prism 41 and reflects the laser light emitted from the laser optical system 30. The slit 43 is for narrowing the beam diameter of the laser light transmitted through the prism 42 and the laser light reflected by the prism 42 to a predetermined size. The laser beam that has passed through the slit 43 is reflected by the prisms 44 and 45, passes through the objective lens 46, and is applied to the surface of the halftone mask 11 mounted on the stage 61.

The slit 43 partitions the laser beam irradiation region on the surface of the halftone mask 11. As shown in FIGS. 1 (b) and 1 (c), the slit 43 is also parallel and adjustable in spacing with the first pair of frames 430, 430 that are parallel and adjustable in spacing. It includes a first pair of frames 430 and 430 and a second pair of frames 431 and 431 that are orthogonal to each other. The laser beam irradiation region is a rectangular opening 432 (hatched portion in the drawing) surrounded by four frames 430, 430, 431, 431 that are orthogonal to each other and has a rectangular shape (a concept including a square shape; the same applies hereinafter). The opening 432 can also be slit-shaped by narrowing the distance between one pair of frames.

The gas supply system 50 is for supplying the raw material gas that is the raw material of the correction film. The gas supply system 50 includes a raw material gas supply pipe 51. The raw material gas is produced by mixing a carrier gas composed of an inert gas with a raw material gasified by heating. The raw material gas supplied from the raw material gas supply pipe 51 is ejected toward the surface of the halftone mask 11, and the defect repair target region on the surface of the halftone mask 11 is used as the raw material gas atmosphere. When the surface of the halftone mask 11 is irradiated with the laser beam from the laser optical system 20 under this raw material gas atmosphere, an irradiation spot is formed and a correction film is formed according to the size and shape of the irradiation spot. A film is formed. As the raw material, for example, a metal carbonyl such as chromium carbonyl, molybdenum carbonyl, or tungsten carbonyl is used.

The position control system 60 is for positioning the portion of the halftone mask 11 to be irradiated with the laser at the laser irradiation position (on the optical axis of the objective lens 46). The position control system 60 includes a stage 61 and a position control unit 62. The stage 61 is configured to be movable in the X and Y directions orthogonal to each other in the horizontal plane on which the halftone mask 11 is placed. The position control unit 62 controls the movement and position of the stage 61.

As a mechanism for changing the laser irradiation position and the relative position of the halftone mask 11, in addition to the mechanism in which the stage 61 moves in the X direction and the Y direction, (i) the stage is fixed and the laser irradiation unit (objective lens). A mechanism may be used in which the head portion including the head portion moves in the X direction and the Y direction, or (ii) one of the head portion and the stage moves in the X direction and the other moves in the Y direction.

<Outline of defect correction method>
In the defect repair method according to the present embodiment, (i) a main film is formed in the defect repair target region of the semitransparent portion of the halftone mask so that the transmittance is equal to the transmittance of the semitransparent portion. Complementary film formation in which a complementary film is formed in the high-transmittance portion that remains in the defect correction target region even after the film-forming step and (ii) film formation of the main film so that the transmittance is equal to the transmittance of the semi-transmissive portion. It is equipped with a membrane process. The defect repair method according to the present embodiment can be roughly divided into three methods according to the size of the defect: the defect repair method 1, the defect repair method 2, and the defect repair method 3.

<Defect correction method 1>
The defect correction method 1 is used when the defect size S is 20 μm or less. In the defect repair method 1, as shown in FIG. 2, roughly, (i) a defect repair target area 5 including a defect 4 generated in the semi-transmissive portion 3 of the halftone mask 11 is set, and a defect repair target is set. The trimming step of removing the existing semi-transmissive film 3 existing in the region 5 and (ii) the defect repair target region 5 so that the transmittance is equal to the transmittance of the semi-transmissive portion 3 and the defect repair target. A main film 8 is formed in a shape that matches the region 5, or a gap is formed between at least a part of the boundary of the defect correction target region 5 and at least a part of the outer edge of the main film 8 to form a main film. Along the boundary of the defect repair target region 5 and the outer edge of the main film 8 in the width from the boundary of the defect repair target region 5 to the outer edge of the main film 8 in the main film film formation step of forming the film 8. The resulting high transmissivity portion is provided with a compensating film film forming step of forming the compensating film 9 so that the transmissivity becomes equal to the transmissivity of the semi-transmissive portion 3. Further, the main film film forming step includes the base layer film forming step of forming the base layer 6 having a transmittance higher than the transmittance of the (ii-i) semi-transmittance portion 3 and the (iii-ii) transmittance. A transmittance adjusting layer film forming step of forming one or a plurality of layers of the transmittance adjusting layer 7 on the base layer 6 is provided so as to be equal to the transmittance of the semi-transmissive portion 3. Further, in the filling film film forming step, the transmittance adjusting layer 9 for forming one or a plurality of layers of the transmittance adjusting layer 9 is formed so that the (iii-i) transmittance becomes equal to the transmittance of the semi-transmissive portion 3. It has a membrane process.

Specifically, the defect repair method 1 includes steps 1 to 4. The fifth step is an arbitrary step.

In the first step (trimming step), the existing half existing in the defect correction target area 5 is used by using the laser optical system 30 in a state where the opening shape of the slit 43 of the defect correction device is matched with the defect correction target area 5. The permeable film 3 is removed. As a result, the defect 4 disappears, and a non-film forming portion in which the outer line is shaped into a rectangular shape, that is, a transmissive portion in which the transparent substrate 1 is exposed in a rectangular shape is formed.

In the second step (base layer film forming step of the main film forming step), the laser optical system 20 is set to have a shape slightly smaller than the defect correction target region 5 in the opening shape of the slit 43 of the defect correction device. Is used to form the base layer 6 in the defect correction target region 5. The base layer 6 is formed by scanning the laser beam in the X and Y directions with the beam scan unit 25 while continuously irradiating the laser beam. The base layer 6 is formed in a rectangular shape corresponding to the opening shape of the slit 43 of the defect correction device.

The reason why the opening shape of the slit 43 is set to a shape slightly smaller than the defect correction target region 5 is as follows. The base layer 6 needs to be formed into a film thickness having a certain thickness in one pass (once). Therefore, the output of the laser optical system 20 when the base layer 6 is formed is set to 100%. If the opening shape of the slit 43 is set to a shape slightly larger than the defect correction target region 5 under a situation where the output of the laser beam is strong, as shown in FIG. 3A, the film formation is defective. Starting from the boundary of the region 5 to be corrected (that is, the end face of the trimmed semitransparent portion 3), a clean film is not formed. In order to form a clean film formation, the opening shape of the slit 43 is set to a shape slightly smaller than the defect correction target region 5. As a result, as shown in FIG. 3B, the base layer 6 is formed so that a gap G is formed between the boundary of the defect correction target region 5 and the outer edge of the base layer 6. Alternatively, the opening shape of the slit 43 may be set to the same shape as the defect correction target region 5. As a result, as shown in FIG. 3C, the base layer 6 is formed so that the outer edge of the base layer 6 is in contact with the boundary of the defect correction target region 5. The gap G is preferably set to be 1 μm or less. In the present embodiment, the gap G is 0.5 μm, which is a dimension equal to or less than the resolution limit.

As described above, the base layer 6 is a CVD film. The transmittance of the base layer 6 has a higher transmittance than the transmittance of the semi-transmissive portion 3. This is because, as a method of adjusting the transmittance of the main film 8, a method of laminating the transmittance adjusting layers 7 to reduce the transmittance is adopted. The transmittance of the base layer 6 is preferably set to be + 10% or more and + 20% or less of the transmittance of the semi-transmissive portion 3. In the present embodiment, the transmittance of the semi-transmissive portion 3 is 30%, whereas the transmittance of the base layer 6 is 40%.

In the third step (transmittance adjusting layer film forming step of the main film forming step), the laser optical system 20 is operated in a state where the opening shape of the slit 43 of the defect correction device is set to the same shape as the defect correction target region 5. In use, the transmittance adjusting layer 7 is formed in the defect correction target region 5. Similar to the base layer 6, the transmittance adjusting layer 7 is formed by scanning the laser light in the X direction and the Y direction with the beam scan unit 25 while continuously irradiating the laser light. The transmittance adjusting layer 7 is formed in a rectangular shape corresponding to the opening shape of the slit 43 of the defect correction device.

The transmittance adjusting layer 7 needs to be formed into a film having a small thickness. If the thickness of the transmittance adjusting layer 7 is large, the transmittance of the main film 8 may be lower than the transmittance of the semi-transmissive portion 3 due to the film formation of the transmittance adjusting layer 7 once. This is because there is an increased risk of having to start over from the second step. Therefore, the output of the laser optical system 20 when the transmittance adjusting layer 7 is formed is set to a value lower than the output of the laser optical system 20 when the base layer 6 is formed. The output of the laser optical system 20 when forming the transmittance adjusting layer 7 is 20% or more and 60% or less, assuming that the output of the laser optical system 20 when forming the base layer 6 is 100%. It is preferable to set as such. In the present embodiment, the output of the laser optical system 20 when the transmittance adjusting layer 7 is formed is 25% to 45%.

In the transmittance adjusting layer film forming step, the transmittance of the main film 8 is measured each time the transmittance adjusting layer 7 is formed. As a method of measuring the transmittance, in addition to a method of directly measuring the transmittance by irradiating light (for example, one central portion of the main film 8) and measuring the amount of transmitted light, the main method is to take an image. Various known transmittance measuring methods such as a method of indirectly measuring the transmittance by comparing the image of the film 8 (for example, the pixel value) and the image of the semitransparent portion 3 (for example, the pixel value) can be used. Can be used.

As a result of the measurement, when the transmittance of the main membrane 8 becomes the same as the transmittance of the semi-transmissive portion 3, or when the difference between the transmittance of the main membrane 8 and the transmittance of the semi-transmissive portion 3 does not matter. The transmittance adjusting layer film forming step, and thus the main film film forming step, is completed, and the main film 8 having an appropriate transmittance as a modifying film is obtained. As the transmittance adjusting layer 7, for example, when two layers of the first layer 7a and the second layer 7b are formed as shown in FIG. 4A, or as shown in FIG. 4B, the first layer 7 is formed. Three layers, a layer 7a, a second layer 7b, and a third layer 7c, may be formed. Alternatively, as shown in FIG. 4C, only one layer of the transmittance adjusting layer 7 may be formed. As shown in FIG. 4D, the film thickness of the transmittance adjusting layer 7 per layer is appropriately adjusted so that the transmittance can be adjusted smoothly and with good yield by forming the transmittance adjusting layer 7. be able to.

In this way, the main film 8 is formed in a rectangular shape corresponding to the opening shape of the slit 43 of the defect correction device. However, due to the intensity distribution (Gaussian distribution) of the laser beam, the film thickness of the outer edge portion of the main film 8 is thinner than the uniform film thickness of the portion excluding the outer edge portion of the main film 8. That is, the transmittance of the outer edge portion of the main film 8 is higher than the uniform transmittance (and the transmittance of the semi-transmissive portion 3) of the portion excluding the outer edge portion of the main film 8. Further, as shown in FIG. 4C, a gap may be formed between the boundary of the defect correction target region 5 and the outer edge of the main film 8 depending on the result of the transmittance adjusting layer film forming step. Of course, the transmittance of this gap portion is higher than the uniform transmittance (and the transmittance of the semi-transmissive portion 3) of the portion of the main film 8 excluding the outer edge portion. Therefore, due to the main film forming step, the width from the boundary of the defect correction target area 5 to the outer edge of the main film 8 is strip-shaped (macroscopically) along the boundary of the defect correction target area 5 and the outer edge of the main film 8. , Streaks) will result in a highly permeable portion.

Therefore, in the fourth step (filling film film forming step), the laser optical system 20 is used in a state where the opening shape of the slit 43 of the defect correction device is set to the slit shape corresponding to one side of the high transmission portion. The filling film 9 is formed on the high-transparency portion in units of one side of the high-transparency portion. When the filling films 9 on each side overlap at the corners of the main film 8, the transmittance decreases only there, so that the filling films 9 are formed so as not to overlap at the corners of the main film 8. The filling film 9 on each side is formed by scanning the laser beam in the X direction and the Y direction with the beam scan unit 25 while continuously irradiating the laser beam.

As shown in FIG. 5, the filling film 9 is composed of the transmittance adjusting layer 9 like the transmittance adjusting layer 7. The transmittance adjusting layer 9 needs to be formed into a film thickness having a small thickness. If the thickness of the transmittance adjusting layer 9 is large, the transmittance of the high transmittance portion may be lower than the transmittance of the semi-transmissive portion 3 due to the film formation of the transmittance adjusting layer 9 once. This is because there is an increased risk of having to start over from the second step. Therefore, the output of the laser optical system 20 when the transmittance adjusting layer 9 is formed is set to a value lower than the output of the laser optical system 20 when the base layer 6 is formed. The output of the laser optical system 20 when forming the transmittance adjusting layer 9 is 20% or more and 35% or less, assuming that the output of the laser optical system 20 when forming the base layer 6 is 100%. It is preferable to set as such. In the present embodiment, the output of the laser optical system 20 when the transmittance adjusting layer 9 is formed is 25% to 35%.

In the transmittance adjusting layer film forming step, the transmittance of the high transmittance portion is measured each time the transmittance adjusting layer 9 is formed. As a method of measuring the transmittance, in addition to a method of directly measuring the transmittance by irradiating light and measuring the amount of transmitted light, an image of a high-transmitt portion (for example, a pixel value) and a half of the image are taken. Various known transmittance measuring methods such as a method of indirectly measuring the transmittance can be used by comparing with the image (for example, the pixel value) of the transmitting unit 3. However, since the highly transparent portion has a narrow band shape, direct measurement is difficult. In this respect, indirect measurement by diagnostic imaging is preferable. Indirect measurement by diagnostic imaging also has the advantage that measurement can be performed in a shorter time than direct measurement.

As a result of the measurement, when the transmittance of the high transmissive portion becomes the same as the transmissivity of the semi-transmissive portion 3, or the difference between the transmissivity of the high transmissive portion and the transmissivity of the semi-transmissive portion 3 does not matter. The transmittance adjusting layer film forming step and, by extension, the filling film film forming step are completed, and the filling film 9 having an appropriate transmittance as a correction film is obtained. As the transmittance adjusting layer 9, for example, as shown in FIG. 5 (a), when three layers of the first layer 9a, the second layer 9b, and the third layer 9c are formed, or as shown in FIG. 5 (b). As described above, two layers, a first layer 9a and a second layer 9b, may be formed. Alternatively, as shown in FIG. 5C, only one layer of the transmittance adjusting layer 9 may be formed. As shown in FIG. 5D, the film thickness of the transmittance adjusting layer 9 per layer is appropriately adjusted so that the transmittance can be adjusted smoothly and with good yield by forming the transmittance adjusting layer 9. be able to.

Through the above steps, the transmittance is uniform over the entire surface of the defect correction target region 5 and equal to the transmittance of the semi-transmissive portion 3 composed of the normal semi-transmissive film around the defect correction target region 5. Membrane 10 is obtained. As described above, according to the defect correction method 1, extremely high-precision defect correction can be realized.

As can be seen from FIG. 2 (e), a part of the filling film 9 is wrapped on the semi-transmissive portion 3 to form a film. However, the film thickness of this wrap portion is extremely thin. Therefore, the effect of reducing the transmittance of the semi-transmissive portion 3 in the wrap portion is extremely small. Therefore, as the fifth step, a step of removing the wrap portion is applied, but the fifth step is positioned as an arbitrary step.

<Defect correction method 2>
The defect correction method 2 is used when the defect size S exceeds 20 μm. Physically, it is possible to do it only once by using the defect correction method 1. However, in that case, the size of the main film 8 to be formed becomes large, the uniformity of the in-plane distribution of the main film 8 (particularly the base layer 6) is broken, and the uniformity of the transmittance of the correction film 10 is impaired. The quality of the correction film 10 and, by extension, the quality of the halftone mask are deteriorated. Therefore, the defect correction method 2 is to divide the defect correction. The defect correction method itself is the same for both the defect correction method 2 and the defect correction method 1. There are roughly five defect repair methods 2 from the defect repair method 2-1 to the defect repair method 2-5, depending on the difference in the order of the processes. Hereinafter, the different points will be mainly described.

<Defect correction method 2-1>
The defect repair method 2-1 includes steps 1 to 8 as shown in FIGS. 6 and 7. The ninth step is the same as the fifth step of the defect repair method 1, and is an arbitrary step.

The defect correction target area 5 is divided into two. First, for the first defect correction target region 5, the first step (trimming step), the second step (base layer film forming step of the main film forming step), and the third step (permeation of the main film forming step). The rate adjustment layer film forming step) and the fourth step (complementary film film forming step) are carried out. However, in the fourth step, the filling film 9 is not formed on the highly transparent portion on one side in contact with the second defect correction target region 5. This is because when the second defect correction target region 5 is trimmed, the highly transparent portion is also trimmed, and even if the filling film 9 is formed, it is useless.

Next, for the second defect correction target region 5, the fifth step (trimming step), the sixth step (base layer film forming step of the main film forming step), and the seventh step (main film forming step). The transmission rate adjusting layer film forming step) and the eighth step (complementary film film forming step) are carried out.

Through the above steps, the transmittance is uniform over the entire surface of the defect correction target region 5 and equal to the transmittance of the semi-transmissive portion 3 composed of the normal semi-transmissive film around the defect correction target region 5. Membrane 10 is obtained. As described above, according to the defect correction method 2-1, extremely high-precision defect correction can be realized even for the defect 4 having a large size.

The configuration of the A part in FIG. 6 (c) is the same as the configuration of the A part in FIG. 2 (c). The configuration of the C portion in FIG. 6 (d) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E portion of FIG. 6 (e) is the same as the configuration of the E portion of FIG. 2 (e). The configuration of the B portion in FIG. 7 (b) is the same as the configuration of the B portion in FIG. 2 (c). The configuration of the D portion in FIG. 7 (c) is the same as the configuration of the D portion in FIG. 2 (d). The configuration of the F portion in FIG. 7 (d) is the same as the configuration of the F portion in FIG. 2 (e). The configuration of the A'part in FIG. 7 (b) is the same as the configuration of the A portion in FIG. 2 (c). The configuration of the C'part in FIG. 7 (c) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E'part in FIG. 7 (d) is the same as the configuration of the E portion in FIG. 2 (e).

<Defect correction method 2-2>
The defect repair method 2-2 includes steps 1 to 7, as shown in FIGS. 8 and 9. The eighth step is the same as the fifth step of the defect repair method 1, and is an arbitrary step.

The defect correction target area 5 is divided into two. First, for the first defect correction target region 5, the first step (trimming step), the second step (base layer film forming step of the main film forming step), and the third step (permeation of the main film forming step). Rate adjustment layer film formation step) is carried out. Unlike the defect repair method 2-1 here, the filling film film forming step is not carried out.

Next, for the second defect correction target region 5, the fourth step (trimming step), the fifth step (base layer film forming step of the main film forming step), and the sixth step (main film forming step). Permeability adjusting layer film formation step) is carried out. Finally, the seventh step (complementary film film forming step) is carried out on the highly permeable portion of the whole (two defect repair target areas 5 and 5).

Through the above steps, the transmittance is uniform over the entire surface of the defect correction target region 5 and equal to the transmittance of the semi-transmissive portion 3 composed of the normal semi-transmissive film around the defect correction target region 5. Membrane 10 is obtained. As described above, even with the defect correction method 2-2, extremely high-precision defect correction can be realized for the defect 4 having a large size. Moreover, the defect repair method 2-2 has one less step than the defect repair method 2-1. Therefore, it is possible to shorten the manufacturing time and, by extension, reduce the manufacturing cost.

The configuration of the A part in FIG. 8 (c) is the same as the configuration of the A portion in FIG. 2 (c). The configuration of the C portion in FIG. 8 (d) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E portion in FIG. 9 (d) is the same as the configuration of the E portion in FIG. 2 (e). The configuration of the B portion in FIG. 9 (b) is the same as the configuration of the B portion in FIG. 2 (c). The configuration of the D portion in FIG. 9 (c) is the same as the configuration of the D portion in FIG. 2 (d). The configuration of the F portion in FIG. 9 (d) is the same as the configuration of the F portion in FIG. 2 (e). The configuration of the A'part in FIG. 9 (b) is the same as the configuration of the A portion in FIG. 2 (c). The configuration of the C'part in FIG. 9 (c) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E'part in FIG. 9D is the same as the configuration of the E portion in FIG. 2E.

<Defect correction method 2-3>
The defect repair method 2-3 includes steps 1 to 6 as shown in FIGS. 10 and 11. The seventh step is the same as the fifth step of the defect repair method 1, and is an arbitrary step.

The defect correction target area 5 is divided into two. First, the first step (trimming step) and the second step (base layer film forming step of the main film forming step) are carried out for the first defect correction target area 5. Unlike the defect repair method 2-1 here, the transmittance adjusting layer film forming step and the filling film film forming step of the main film forming step are not carried out.

Next, the third step (trimming step) and the fourth step (base layer film forming step of the main film forming step) are carried out for the second defect correction target area 5. Next, the fifth step (transmittance adjusting layer film forming step of the main film forming step) is carried out for the whole (two defect repair target areas 5 and 5). Finally, the sixth step (complementary film film forming step) is carried out on the highly permeable portion of the whole (two defect repair target areas 5 and 5).

Through the above steps, the transmittance is uniform over the entire surface of the defect correction target region 5 and equal to the transmittance of the semi-transmissive portion 3 composed of the normal semi-transmissive film around the defect correction target region 5. Membrane 10 is obtained. As described above, even with the defect correction method 2-3, extremely high-precision defect correction can be realized for the defect 4 having a large size. Moreover, the defect repair method 2-3 has two steps less than the defect repair method 2-1 and one step less than the defect repair method 2-2. Therefore, it is possible to shorten the manufacturing time and, by extension, reduce the manufacturing cost.

The configuration of the A part in FIG. 10 (c) is the same as the configuration of the A part in FIG. 2 (c). The configuration of the C portion in FIG. 11 (c) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E portion in FIG. 11 (d) is the same as the configuration of the E portion in FIG. 2 (e). The configuration of the B portion in FIG. 11 (b) is the same as the configuration of the B portion in FIG. 2 (c). The configuration of the D portion in FIG. 11 (c) is the same as the configuration of the D portion in FIG. 2 (d). The configuration of the F portion in FIG. 11 (d) is the same as the configuration of the F portion in FIG. 2 (e). The configuration of the A ″ portion in FIG. 11 (b) is the same as the configuration of the A portion in FIG. 2 (c). The configuration of the C ″ portion in FIG. 11 (c) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E ″ portion in FIG. 11 (d) is the same as the configuration of the E portion in FIG. 2 (e).

<Defect correction method 2-4>
As shown in FIG. 12, the defect repair method 2-4 includes the first step to the fourth step. The fifth step is the same as the fifth step of the defect repair method 1, and is an arbitrary step.

The defect correction target area 5 is divided into two. However, the first step (trimming step) is carried out once for the whole. Next, for the whole (two defect repair target areas 5 and 5), the second step (base layer film forming step of the main film forming step) and the third step (transmittance adjusting layering of the main film forming step). Membrane step) is carried out. Finally, the fourth step (complementary film film forming step) is carried out on the highly permeable portion of the whole (two defect repair target areas 5 and 5).

Through the above steps, the transmittance is uniform over the entire surface of the defect correction target region 5 and equal to the transmittance of the semi-transmissive portion 3 composed of the normal semi-transmissive film around the defect correction target region 5. Membrane 10 is obtained. As described above, even with the defect correction method 2-4, extremely high-precision defect correction can be realized for the defect 4 having a large size. Moreover, the defect repair method 2-4 has four steps less than the defect repair method 2-1 and three steps less than the defect repair method 2-2, and has three steps less than the defect repair method 2-3. Is reduced by 2 steps. Therefore, it is possible to shorten the manufacturing time and, by extension, reduce the manufacturing cost.

The configuration of the A part in FIG. 12 (c) is the same as the configuration of the A part in FIG. 2 (c). The configuration of the C portion in FIG. 12 (d) is the same as the configuration of the C portion in FIG. 2 (d). The configuration of the E portion of FIG. 12 (e) is the same as the configuration of the E portion of FIG. 2 (e). The configuration of the B portion in FIG. 12 (c) is the same as the configuration of the B portion in FIG. 2 (c). The configuration of the D portion in FIG. 12 (d) is the same as the configuration of the D portion in FIG. 2 (d). The configuration of the F portion in FIG. 12 (e) is the same as the configuration of the F portion in FIG. 2 (e). The configurations of the A ″ and B ″ of FIG. 12 (c) are the same as the configurations of the A and B portions of FIG. 2 (c). The configurations of the C ″ and D ″ of FIG. 12 (d) are the same as the configurations of the C and D portions of FIG. 2 (d). The configurations of the E ″ and F ″ parts of FIG. 12 (e) are the same as the configurations of the E and F parts of FIG. 2 (e).

<Defect correction method 2-5>
The defect repair method 2-5 includes steps 1 to 8 as shown in FIGS. 13 and 14. The ninth step is the same as the fifth step of the defect repair method 1, and is an arbitrary step.

The difference between the defect correction method 2-5 and the defect correction method 2-1 is that in the defect correction method 2-1 the two defect correction target areas 5 and 5 are set to wrap at a part (ends). On the other hand, in the defect correction method 2-5, the two defect correction target areas 5 and 5 are set not to wrap, or even if they are wrapped, they are set to wrap in a very small amount. As a result, in the defect repair method 2-1, a part of the film formed on the first defect repair target region 5 is trimmed by the trimming step performed on the second defect repair target region 5. On the other hand, in the defect repair method 2-5, the film formed on the first defect repair target region 5 is trimmed on the second defect repair target region 5. It also makes a difference that it is not removed, or even if it is removed, only a very small amount is removed. There is no difference in the final finish.

The method of not wrapping the defect repair method 2-5 can naturally be applied to the defect repair method 2-2 and the defect repair method 2-3.

<Defect correction method 3>
The defect repair method 3 is used when the defect size S is 2 μm or less. As shown in FIG. 15, the defect repair method 3 does not generally include (i) a trimming step, and (ii) the transmittance is semi-transparent partially in the defect repair target area 5 (defect 4 as it is). The transmissivity is semi-transmissive in the main film forming step of forming the main film 8 so as to be equal to the transmittance of the part 3 and in the high transmissive part (iii) generated in the place where the main film 8 is not buried. A filling film film forming step of forming the filling film 9 is provided so as to have the same transmittance as that of the above.

Specifically, the defect repair method 3 includes the first step to the third step. In the first step (main film film forming step) and the second step (main film forming step), the main film 8 is formed in most of the defect correction target region 5 by using the laser optical system 20. .. The main film 8 is one or more spot-shaped film formations. The main film 8 is formed under the same conditions as the base layer 6 of the defect correction method 1 and the like. In the third step (filling film film forming step), the filling film 9 is formed on the remaining region of the defect correction target region 5 by using the laser optical system 20. The filling film 9 is also a spot-shaped film formed, and is formed under the same conditions as the base layer 6 of the defect correction method 1 and the like.

Through the above steps, the transmittance is uniform over the entire surface of the defect correction target region 5 and equal to the transmittance of the semi-transmissive portion 3 composed of the normal semi-transmissive film around the defect correction target region 5. Membrane 10 is obtained. As described above, according to the defect correction method 3, it is possible to realize simple and highly accurate defect correction for the defect 4 having a small size.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, in the above embodiment, a defect repair method for a defect 4 having only a semitransparent portion 3 around it will be described. However, the present invention is not limited to this. For example, as shown in FIG. 16, the defect repair method according to the present invention is applied to the defect 4 generated in the vicinity of the light-shielding portion 2 (the portion where the semi-transmissive film 3 is laminated on the light-shielding film 2). It goes without saying that it is possible. When there is a light-shielding portion 2 in the vicinity of the defect 4, as shown in FIG. 16B, the trimming region is set so as not to overlap with the light-shielding portion 2 in the trimming step. That is, the trimming region is set so as to be in contact with the boundary (outer edge of the light-shielding portion 2) of the light-shielding portion 2 with the semi-transparent portion 3. This is to trim only the semitransparent portion 3 and prevent the light-shielding portion 2 from being trimmed. However, as shown in FIGS. 16C and later, in each film forming step after the trimming step, the defect correction target region 5 is set so as to overlap the light-shielding portion 2. This is because a high transmissive portion does not occur on the light-shielding portion 2, and no matter how the film is formed on the light-shielding portion 2, the transmittance of the light-shielding portion 2 is not affected. .. As a result, in the filling film film forming step, with respect to the highly permeable portion (in the example of FIG. 16D, the highly permeable portion on two sides) that occurs only in the semitransparent portion 3 of the outer edge portion of the main film 8. Is done. Therefore, the time required for the filling film film forming process can be shortened, and the manufacturing cost can be reduced.

Further, in the above embodiment, the defect correction of the white defect is described. However, the present invention is not limited to this. The defect correction target may be a black defect.

Further, in the above embodiment, the case where the semi-transmissive membrane constituting the semi-transmissive portion 3 is a single layer has been described. However, the present invention is not limited to this. The semi-transmissive membrane may be a laminated semi-transmissive membrane laminated in two layers or three or more layers. Then, for i) white defects generated in the non-surface layer (lower layer in the case of a two-layer structure) of the laminated semi-transmissive film, either the defect repair method 1 or the defect repair method 2 is performed according to the size of the defect. (If the size of the defect is the corresponding size of the defect correction method 3, the defect correction method 1 is used). ii) For white defects generated on the surface layer (upper layer in the case of a two-layer structure) of the laminated semi-transmissive film, the defect correction method 1, the defect correction method 2 or the defect correction method 3 is performed according to the size of the defect. Either is used. iii) For the black defect generated in the laminated semi-transmissive film, either the defect correction method 1 or the defect correction method 2 is used.

Further, in the above embodiment, due to the structure of the slit 43 of the defect correction device, the defect correction target area 5 and the trimming area are rectangular. However, the present invention is not limited to this. By adopting an appropriate mask shape, an appropriate shape can be set as the shape of the defect correction target area and the trimming area. Alternatively, by appropriately controlling the laser beam, it is possible to form a correction film without using a slit.

Further, in the above-mentioned defect repair methods 1 and 2, a trimming step is carried out. However, the present invention is not limited to this. Depending on the shape of the defect, it may be possible to set the defect as it is in the defect correction target area. In this case, the trimming step is unnecessary.

Further, in the defect repair methods 1 and 2, the main film forming step includes a base layer forming step and a transmittance adjusting layer forming step. However, the present invention is not limited to this. When the desired correction film can be obtained only with the base layer, the transmittance adjusting layer film forming step is unnecessary.

Further, in the above-mentioned defect correction method 2, the defect correction is divided into two parts. However, the present invention is not limited to this. The number of divisions may be three or more.

Further, in the above embodiment, laser CVD is used as a film forming means for the correction film 10. However, the present invention is not limited to this. The present invention can be applied to all defect correction methods using a film forming means such that a high transmission portion is generated due to a thin film thickness of the outer edge portion.

Terms that specify a shape or state, such as "equal," "match," "same," and "rectangular," include themselves, as well as the concept of "abbreviation," which means close or similar.

1 ... Transparent substrate (glass substrate), 2 ... Light-shielding film (light-shielding part), 3 ... Semi-transmissive film (semi-transmissive part), 4 ... Defect (white defect), 5 ... Trimming area (defect correction target area), 6 ... Base layer, 7 ... Transmittance adjusting layer, 7a ... Transmittance adjusting layer (first layer), 7b ... Transmittance adjusting layer (second layer), 7c ... Transmittance adjusting layer (third layer), 8 ... Main film , 9 ... Filling film, 9a ... Transmittance adjusting layer (first layer), 9b ... Transmittance adjusting layer (second layer), 9c ... Transmittance adjusting layer (third layer), 10 ... Correcting film, 11 ... Half Tone mask, 20 ... laser optics, 21 ... laser oscillator, 22 ... collimating lens, 23 ... beam expander, 24 ... attenuator, 25 ... beam scan unit, 30 ... laser optics, 31 ... laser oscillator, 32 ... collimating lens , 33 ... Beam expander, 34 ... Attenuator, 40 ... Optical system, 41 ... Prism, 42 ... Prism, 43 ... Slit, 430 ... Frame, 431 ... Frame, 432 ... Opening, 44 ... Prism, 45 ... Prism, 46 ... Objective lens, 50 ... gas supply system, 51 ... raw material gas supply pipe, 60 ... position control system, 61 ... stage, 62 ... position control unit

Further, the halftone mask according to the present invention is
A halftone mask having a light-shielding portion, a transmissive portion, and a semi-transmissive portion on a transparent substrate and a correction film on the semi-transmissive portion.
The correction membrane is
A main film formed so that the transmittance is equal to the transmittance of the semi-transmissive part,
It is a halftone mask provided with a high-transmittance portion that is not equal to the transmittance of the semi-transmissive portion by the main film alone, and a compensating film formed so that the transmittance is equal to the transmittance of the semi-transmissive portion.

Claims (10)

This is a method for correcting defects in a halftone mask by forming a correction film in a region to be corrected for defects in the semitransparent portion of the halftone mask to correct defects generated in the semitransparent portion.
A main film film forming step of forming a main film in the defect repair target area so that the transmittance is equal to the transmittance of the semi-transmissive portion.
A halftone mask provided with a compensating film film forming step of forming a compensating film so that the transmittance is equal to the transmissivity of the semi-transmissive part in the highly transmissive portion remaining in the defect correction target region even after the film formation of the main film. Defect correction method. In the main film film forming step, the main film is formed in a shape that matches the defect correction target area, or a gap is formed between at least a part of the boundary of the defect correction target area and at least a part of the outer edge of the main film. To form a film on the main film.
In the compensation film film forming step, a filling film is formed on the boundary of the defect correction target area and the highly permeable portion formed along the outer edge of the main film in the width from the boundary of the defect correction target area to the outer edge of the main film. The method for correcting defects in a halftone mask according to claim 1. The main film film formation process is
A base layer film forming process for forming a base layer having a transmittance higher than that of the semitransparent part, and
1. 2. The method for correcting defects in a halftone mask according to 2. In the base layer film forming step, the base layer is formed so that a gap is formed between the boundary of the defect correction target area and the outer edge of the base layer, or the outer edge of the base layer is formed at the boundary of the defect correction target area. The defect repair method for a halftone mask according to claim 3, wherein a base layer is formed so that the two are in contact with each other. The first to claim Item 8. The method for correcting defects in a halftone mask according to any one of Item 4. Claims 1 to 5 include a trimming step of setting a defect repair target region having a predetermined shape including defects and removing an existing semi-transmissive film existing in the defect repair target region prior to the main film film forming step. The method for correcting defects in a halftone mask according to any one of the above items. The defect correction method for a halftone mask according to any one of claims 1 to 6, wherein when the defect exceeds a predetermined size, the defect correction target area is divided into a plurality of parts and the defect is corrected. The method for repairing defects in a halftone mask according to any one of claims 1 to 7, wherein a repair film is formed by irradiating a region to be repaired with a laser beam in an atmosphere of a raw material gas. A process of forming a light-shielding portion, a transmissive portion, and a semi-transmissive portion on a transparent substrate,
It is equipped with a defect correction process that corrects defects that occur in the semi-transparent part.
A method for manufacturing a halftone mask to which the defect repair method according to any one of claims 1 to 8 is applied as a defect repair step. A light-shielding part, a transmissive part, and a semi-transparent part are provided on the transparent substrate.
A halftone mask provided with a correction film in a semi-transmissive portion by applying the defect correction method according to any one of claims 1 to 8.

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