JP2006011121A - Phase shift mask, its manufacturing method, and method for transferring pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase shift mask having a simple structure which requires neither recessed part on a substrate surface nor multilayer film structure and manufacturing steps of which are not increased, in the phase shift mask which inverts a phase difference between transmission light passing through a recessed part formed on a substrate surface and transmission light adjacent to it, and to provide a method for manufacturing the phase shift mask and a method for transferring a pattern. <P>SOLUTION: The phase shift mask has a refractive index varied portion in a transparent substrate, which generates 180° phase difference between transmission light passing through in the refractive index varied portion and transmission light passing through the transparent substrate. By the method for manufacturing a phase shift mask, the refractive index varied portion in the transparent substrate is formed by converging laser light into the position in the transparent substrate to induce laser ablation to produce a high-density portion or a hole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a phase shift photomask used for transferring a circuit pattern in a manufacturing process of a semiconductor integrated circuit, for example, a manufacturing method thereof, and a pattern transfer method.

  Conventionally, when a semiconductor element, a thin film magnetic head, a liquid crystal display element or the like is manufactured by a photolithography process, an image of a pattern formed on a photomask is projected onto a substrate coated with a photosensitive agent such as a photoresist on the surface. An exposure system that projects through a system is used. In recent years, with the miniaturization of a pattern shape projected on a shot area on a substrate, the exposure illumination light used (hereinafter referred to as exposure light) tends to be shortened in wavelength. That is, an exposure apparatus using a KrF excimer laser (wavelength 248 nm) or an ArF excimer laser (wavelength 193 nm) has been put into practical use in place of the mercury lamps that have been mainstream. In recent years, an exposure method using an F2 laser (wavelength of 157 nm) has been developed for further miniaturization of the pattern shape.

  In addition to shortening the wavelength of the exposure light, as one method for improving the resolution of the projection exposure optical system, an optical that improves the pattern resolution by changing the phase of the light transmitted through two adjacent transparent portions on the photomask. A phase shift method using various effects has been adopted. As this method, a transmission type (Levenson) phase shift mask and an attenuation type (halftone) phase shift mask have been devised.

  A conventional transmission type phase shift mask forms a recess carved in the cross-sectional depth direction from the substrate surface at a position where a phase shift is desired in the transmission portion pattern portion on the substrate surface. On the other hand, the principle of the attenuation type phase shift mask is to perform phase inversion control of the transmission part of the exposure light by forming a shift pattern film called a shifter on the substrate surface. When the film thickness of the phase shift portion is d, the refractive index is n, and the exposure wavelength is λ, the phase inversion control is performed by forming the phase shift portion so as to satisfy the relationship d = λ / 2 (n−1). In this phase inversion control, the light intensity is zero at the pattern boundary portion because the phase is opposite to the transmitted light of the adjacent transmission portion (shift of about 180 degrees), the pattern is separated, and the resolution is improved.

  In addition, in the transmission type phase shift mask, the problem that the light amount of the concave portion is reduced due to the influence of the side wall of the phase inversion concave portion cannot be ignored due to the miniaturization of the pattern and the proximity between the adjacent patterns and the high density. An invention (see Patent Document 1 and FIG. 11) in which a concave portion is formed also in a non-phase inversion portion has been made. FIG. 11 is a side sectional view of an example of a conventional transmission type phase shift mask. A pattern 110A, a non-phase shift transparent portion 110B, and a phase shift transparent portion 110C are formed on one side of the transparent substrate 10. Concave portions are formed on the exposed transparent substrate surfaces of the non-phase shift transparent portion 110B and the phase shift transparent portion 110C. Further, since the intensity of transmitted light that passes through the inside of the substrate changes depending on whether or not the opening is engraved, the concave portion is undercut to the lower layer of the light shielding portion formed of metal or metal oxide, and the light shielding member An application for a structure (庇) overhanging from the base substrate, or an invention of a structure in which the cross-sectional shape of the recess is inclined to eliminate this overhang (庇), and the light shielding film is formed on the inclined surface instead of the vertical section (Patent Document 2) Has been made.

The known literature is described below.
JP 07-306524 A JP 2002-268197 A

  The conventional transmission type phase shift mask complicates the manufacturing process, such as the structure intensity of the light-shielding part (庇) and the exposure twice (repeating the lithography twice) to form each of the phase inversion part and the non-phase inversion part. I couldn't escape. Furthermore, it is impossible to form a stopper (end point) layer that limits the depth by etching the depth of the concave portion of the phase inversion portion. Also for the attenuation type phase shift mask, it is necessary to form a phase shift portion on the substrate surface, and it is necessary to control both the transmittance and the phase angle at the same time. Examples of the material include metal oxide and SOG (Spin On Glass) methods such as coating, sputtering, chemical vapor deposition, and chemical liquid growth. Further, like the transmission type phase shift mask, it is necessary to expose twice in order to form the transmission part and the phase shift part. Furthermore, there is a known technique that claims the necessity of a stopper layer that suppresses etching of the glass surface in pattern formation by etching of the non-phase shift portion. For the transmission type phase shift mask, it is necessary to form a recess on the substrate surface, and for the attenuation type phase shift mask, it is necessary to control both the transmittance and the phase for the single layer film structure. Therefore, in some cases, a multi-layered film structure in which each control is separated is necessary, and there is a problem that the structure is complicated and the number of processes increases.

  An object of the present invention is a phase shift mask that does not require the formation of recesses on the substrate surface, does not require a multi-layer film structure, has a simple structure, and does not increase the manufacturing process of the phase shift mask. A phase shift mask, a manufacturing method thereof, and a pattern transfer method are provided.

  The invention according to claim 1 of the present invention has a refractive index changing portion inside the transparent substrate, and the phase difference between the transmitted light transmitted through the refractive index changed portion and the transmitted light transmitted through the transparent substrate is approximately 180. It is a phase shift mask characterized by having a degree.

  The invention according to claim 2 of the present invention is the phase shift mask according to claim 1, wherein the refractive index changing portion has a high refractive index or a low refractive index relative to the refractive index of the transparent substrate itself. is there.

  The invention according to claim 3 of the present invention is the phase shift mask according to claim 1 or 2, wherein the refractive index changing portion is made of a transparent substrate or a vacuum hole having a high density.

  The present invention is a photomask having a phase shift effect, in which a refractive index changing portion is expressed inside a transparent substrate, not a surface of the transparent substrate, and a phase shift portion is formed inside the transparent substrate.

  The invention according to claim 4 of the present invention has a refractive index changing portion inside the transparent substrate, and the phase difference between the transmitted light transmitted through the refractive index changed portion and the transmitted light transmitted through the transparent substrate is approximately 180 degrees. In the method of manufacturing a phase shift mask, the refractive index changing portion is formed by laser ablation that converges and expresses laser light at the position inside the transparent substrate. .

According to the present invention, in a photomask having a phase shift effect, the shift portion is formed inside the substrate by using laser ablation for converging the laser light not inside the substrate surface but inside the substrate to develop the refractive index changing portion. Laser ablation uses a nonlinear optical phenomenon of ultrashort pulse light, and when the light is condensed inside a transparent medium that does not absorb with one photon, the medium is located near the focal point due to the nonlinear optical effect. This is a technique that can induce a three-dimensional localized structural change only in a spatially limited region. Multiphoton ionization occurs due to the energy focused at the focal point, and the free electrons generated at this time collide with surrounding atoms and ions, resulting in avalanche ionization. At this time, in the vicinity of the condensing point, the plasma density increases rapidly and at the same time, the absorption coefficient increases, the photons are absorbed by the electrons, and the plasma confined in the minute region is diffused explosively. This shock wave forms a refractive index change and holes.

The invention according to claim 5 of the present invention is the method for manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is a femtosecond (1 × 10 ⁻¹⁵ seconds) pulse laser. .

The invention according to claim 6 of the present invention is the method of manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is an attosecond (1 × 10 ⁻¹⁸ second) pulse laser. .

The invention according to claim 7 of the present invention is the method of manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is a zept second (1 × 10 ⁻²¹ sec) pulse laser. .

The invention according to claim 8 of the present invention is the method of manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is a joctosecond (1 × 10 ⁻²⁴ seconds) pulse laser.
It is.

  Fine structure processing technology using ultra-short pulse laser (femtosecond laser) can be controlled to the laser wavelength or less as the processing size. For example, a titanium sapphire laser with a wavelength of 800 nm uses a BBO (β-barium borate) crystal plate. By transmitting the light, it is converted to 266 nm of the third harmonic, and the size can be controlled to 1/10 to 3/5.

  The invention according to claim 9 of the present invention is a pattern transfer method for improving the resolution using the phase difference of the phase shift mask, and using the phase shift mask according to any one of claims 1 to 3 for photolithography. A pattern transfer method characterized in that a pattern is formed on a transfer substrate by exposure transfer by a method.

  According to such a pattern transfer method, pattern exposure can be performed with high accuracy on the resist formed on the transfer substrate, and as a result, patterns of semiconductors and the like can be manufactured with a high yield.

  According to the present invention, in the transmission type phase shift mask, it is not necessary to form a recess on the substrate surface. When there is a light shielding film, the surface of the transparent substrate is exposed only once to the light shielding layer. Pattern formation is sufficient. Further, since there is no overhang (庇) of the light shielding layer, the structural strength does not decrease, and the problem of dust staying under the overhang (庇) in the cleaning process does not occur.

In addition, according to the present invention, the conventional structure in which the light-shielding portion is also provided on the bottom surface of the recess and the side wall slope eliminates the need for the second exposure whose focal plane is different from the substrate surface, thereby eliminating the conventional drawbacks. Furthermore, in the method using wet etching with a chemical solution, the end point control of the recess depth is affected by changes in the concentration (saturated solubility) of the etching solution and changes in the solution temperature (chemical reaction heat), but this method has no effect. In the first place, in the present invention, the substrate etching chemical itself is unnecessary, and no waste liquid is generated. Similarly, as compared with the dry etching method using a corrosive gas, the etching gas itself is unnecessary, and the gas detoxification process is also unnecessary. In common with wet and dry etching, there is an effect that the concept of the selection ratio between the substance to be etched (glass substrate) and the resist pattern is also unnecessary. Further, the method using laser ablation according to the present invention is preferable because it acts only on the inside of the glass and does not generate dust during processing. Further, according to the present invention, in the attenuation type phase shift mask, the phase shift film does not require the refractive index control, and only the transmittance can be controlled. Furthermore, there is no influence of alteration of the phase shift film surface or internal penetration due to chemical treatment, such as changes in transmittance, reflectance, refractive index, and the like. Therefore, the present invention eliminates the disadvantages of the conventional transmission type and attenuation type two phase shift masks.

  According to the pattern transfer method of the present invention, it is possible to accurately perform pattern exposure on a resist formed on a transfer substrate, and as a result, a pattern of a semiconductor or the like can be manufactured with a high yield.

  First, the structure of the phase shift unit necessary for the phase shift mask of the present invention will be described. 10A and 10B are side cross-sectional views for explaining the structure of the phase shift portion. FIG. 10A is a structure of the present invention, and FIG. 10B is a conventional structure. The principle of phase inversion is based on the difference in the refractive index of the substrate material of the phase shift unit and the refractive index of the environmental medium. It is to shift. That is, the pattern is separated by utilizing the fact that the light intensity becomes zero at the boundary between the light transmitted through the phase shift portion and the light transmitted through the substrate substrate of the transparent substrate by the branched exposure light. When the distance in the substrate cross-sectional direction of the phase shift portion is d, the refractive index of the substrate material of the transparent substrate is n2, the density of the environmental medium in which the transparent substrate is installed is n1, and the exposure wavelength is λ, d = λ / 2 ( It is only necessary to satisfy the relationship of n2-n1).

  Hereinafter, the structure of the phase shift unit of the present invention will be described with reference to FIG. The exposure light branches off and enters from the surface position C of the transparent substrate 10, one of which passes through the phase shift transparent portion 110C, that is, the substrate material 10, the phase shift portion 140, and the substrate material 10 again, The light is emitted from the back surface position A of the transparent substrate into the atmosphere. The other is transmitted through the non-phase shift transparent portion 110B, that is, only through the substrate material 10, and is emitted from the transparent substrate back surface position A into the atmosphere. At this time, the phases of both exposure lights at the back surface position A of the transparent substrate are inverted. In the present invention, the refractive index of the phase shift unit 140 is zero in the case of a vacuum, for example. Therefore, the density n1 of the environmental medium is not an application of the conventional refractive index 1 of the atmosphere (air), but a phase newly generated in this structure. The vacuum zero generated as the refractive index of the shift unit 140 is applied. Therefore, in the case of forming the phase shift portion (140) of the transmission type phase shift mask, when λ is calculated as F2 laser wavelength 157 nm and the refractive index n1 of glass is 1.5, in the present invention, d = 157/2 (1.5 −0) = 52.3 nm. In the calculation formula, the phase shift portion (140) of the present invention is formed in the layer of the transparent substrate, and the depth of the phase shift portion 140 is df from B2 to B1. In laser ablation irradiation, the laser is focused on the depth position of B1 inside the transparent substrate, and irradiation processing is performed under predetermined irradiation conditions, and the processing is performed by sequentially moving the focus position to B2 in stages. The phase shift part can be formed.

The structure of the conventional phase shift unit will be described with reference to FIG. The exposure light branches off and enters from the surface position C of the transparent substrate 10, and one of the light passes through the phase shift transparent portion 110C, that is, the substrate material 10 and the phase shift portion 140A of the recess made of the density n1 of the environmental medium. And is emitted from the back surface position A of the transparent substrate into the atmosphere. The other is transmitted through the non-phase shift transparent portion 110B, that is, only through the substrate material 10, and is emitted from the transparent substrate back surface position A into the atmosphere. The density n1 of the environmental medium of the phase shift unit 140A is the atmosphere (air), and its refractive index is 1. Therefore, in the conventional method shown in FIG. 10B, when λ is calculated with the wavelength of 157 nm of the F2 laser and the refractive index n1 of the glass is 1.5 in the formation of the concave portion of the transmission type phase shift mask,
The density n1 of the environmental medium is the refractive index 1 of the conventional atmosphere (air), and the thickness of the concave portion is d = 157/2 (1.5-1) = 157 nm. In the calculation formula, the conventional phase shift portion 140A is formed on the back surface of the transparent substrate, and the depth of the phase shift portion 140A is d from the transparent substrate back surface position A to B.

  The structure of the phase shift mask according to the first embodiment of the present invention is shown in FIG. FIG. 1 is a cross-sectional view of a photomask 100, which is a part of a line pattern arrangement. A light-shielding portion pattern 110A and a phase-shifting transparent portion 110C and a non-phase-shifting portion 110B are formed on the surface of the transparent substrate 10 on the transparent substrate 10 mainly composed of synthetic quartz. The pattern 110A is formed by a photolithography method or the like with an opaque material such as a metal such as Cr or a metal oxide with respect to the wavelength of exposure light used in the phase shift mask of the present invention. The phase shift portion 140 that develops the phase shift is formed in the cross section of the transparent substrate 10 immediately below the phase shift transparent portion 110C. The phase shift portion 140 is formed to have the same width as or larger than the opening width 150 of the phase shift transparent portion 110C.

  The manufacturing method of the phase shift mask of Example 1 of this invention is demonstrated using FIG. Example 1 is an example of improving the defect of the conventional transmission type, and has the structure shown in FIG. 1, and the formation of the phase shift part is a process after the formation of the light shielding part. First, the light shielding layer 110 is formed on one surface of the transparent substrate 10 as shown in FIG. Next, an electron beam or a photosensitive resin (hereinafter referred to as a resist) 200 is applied on one surface of the light shielding layer 110 (FIG. 2B), exposed and developed by an electron beam drawing apparatus or a laser drawing apparatus, respectively. A resist pattern portion 210A, a non-phase shift resist pattern portion 210B, and a phase shift resist pattern portion 210C in which an electron beam or a photosensitive resin is formed in a predetermined shape are formed. The resist pattern portions 210A, 210B, and 210C correspond to the light shielding portion pattern 110A, the non-phase shift portion 110B, and the phase shift transparent portion 110C in FIG. 1, respectively (FIG. 2C). Next, in order to form the light-shielding portion pattern 110A, the light-shielding portion 110 is etched with a chemical solution or gas that shows an etching reaction until it reaches the surface of the transparent substrate 10 (FIG. 2D). Next, the photosensitive resin 200 formed on the light shielding portion 110 is stripped by dissolution, decomposition, carbonization, or the like with a chemical solution. At this time, the light-shielding part pattern 110A, the non-phase shift transparent part 110B, and the phase shift transparent part 110C are formed (FIG. 2E). Next, a phase shift portion 140 is formed in the layer of the transparent substrate 10, and a refractive index change layer having a predetermined dimension is formed by laser ablation just below the phase shift transparent portion 110C (FIG. 2 (f)). Since the formation of the phase shift part 140 requires laser irradiation, the irradiation process is performed from the side opposite to the pattern 110A of the light shielding film part. A phase shift mask was obtained by the above process.

  In the first embodiment using FIG. 2, the phase shift portion 140 is formed after the light shielding film portion 110 is formed, but can be formed before the light shielding film portion 110 is formed. In this case, the laser irradiation direction is a transparent substrate. It is clear that either of the 10 sides can be used.

  FIG. 3 shows a side sectional structure of the phase shift mask according to the second embodiment of the present invention. A non-phase shift transparent portion 310B and a transmittance control pattern 310A are formed on one side of the transparent substrate 10, and a phase shift portion 140 is formed immediately below the transmittance control pattern 310A.

A method of manufacturing the phase shift mask according to the second embodiment of the present invention will be described with reference to FIG. This embodiment is an example of improving the drawbacks of the conventional attenuation type, and has the structure shown in FIG. Descriptions similar to those of the first embodiment are made using the same symbols. First, the transmittance control layer 310 is formed on one surface of the transparent substrate 10 as shown in FIG. Next, an electron beam or a photosensitive resin (hereinafter referred to as a resist) 200 is applied on one surface of the transmittance control layer 310 (FIG. 4B), and exposed and developed by an electron beam drawing apparatus or a laser drawing apparatus, respectively. Then, a resist pattern portion 210A in which an electron beam or a photosensitive resin is formed in a predetermined shape and a non-phase shift transparent portion resist pattern portion 210B are formed. The resist pattern part 210A and the non-phase shift transparent part resist pattern part 210B correspond to the transmittance control part 310A and the non-phase shift part 310B in FIG. 3, respectively (FIG. 4C). Next, in order to form the non-phase shift portion 310B, the transmittance control layer 310 is etched with a chemical solution or gas that exhibits an etching reaction until it reaches the surface of the transparent substrate 10 (FIG. 4D). Next, the photosensitive resin 200 formed on the transmittance control layer 310 is stripped by dissolution, decomposition, carbonization, or the like with a chemical solution. At this point, the transmittance control unit 310A and the non-phase shift transparent unit 310B are formed (FIG. 4E). Next, a refractive index changing layer having a predetermined size is formed by laser ablation just below the transmittance control unit 310A in the phase shift unit 140 in the transparent substrate 10 (FIG. 4F). Since the formation of the phase shift unit 140 requires laser irradiation, irradiation processing is performed from the side opposite to the transmittance control layer 310. A phase shift mask was obtained by the above process. The light intensity distribution according to this example is also shown in FIG.

  FIG. 5 shows a side sectional structure of the phase shift mask according to the third embodiment of the present invention. A transmittance control pattern 310A and a phase shift transparent portion 310C are formed on one side of the transparent substrate 10, and a phase shift portion 140 is formed immediately below the phase shift transparent portion 310C.

  A method of manufacturing the phase shift mask according to the third embodiment of the present invention will be described with reference to FIG. The manufacturing method is the same as that of the second embodiment, and the same number is used for the same description. First, the transmittance control layer 310 is formed on one surface of the transparent substrate 10 as shown in FIG. Next, an electron beam or a photosensitive resin 200 is applied on one surface of the transmittance control layer 310 (FIG. 6B), exposed with an electron beam drawing apparatus or a laser drawing apparatus, developed, and processed into a predetermined shape. A resist pattern portion 210A on which a line or a photosensitive resin is formed and a phase shift transparent portion resist pattern portion 210C are formed. The resist pattern portion 210A and the phase shift transparent portion resist pattern portion 210C correspond to the transmittance control portion 310A and the phase shift transmission portion 310C in FIG. 5, respectively (FIG. 6C). Next, in order to form the phase shift transparent portion 310C, the transmittance control layer 310 is etched with a chemical solution or a gas showing an etching reaction until it reaches the surface of the transparent substrate 10 (FIG. 6D). Next, the photosensitive resin 200 formed on the transmittance control layer 310 is stripped by dissolution, decomposition, carbonization, or the like with a chemical solution. At this point, the transmittance control unit 310A and the phase shift transparent unit 310C are formed (FIG. 6E). Next, a refractive index changing layer having a predetermined dimension is formed by laser ablation just below the phase shift transmission part 310C and the phase shift part 140 in the transparent substrate 10 (FIG. 6F). Since the formation of the phase shift unit 140 requires laser irradiation, the irradiation process is performed from the side opposite to the transmittance control unit 310A. A phase shift mask was obtained by the above process. The light intensity distribution according to this example is also shown in FIG.

  Hereinafter, Examples 4 to 6 of the present invention compare the structure of the conventional phase shift and the structure of the present invention, and are examples of examples applicable to the optical proximity effect correction pattern.

A fourth embodiment of the present invention is shown in FIG. FIG. 7A is a plan view of the phase shift mask using the auxiliary pattern, and the auxiliary pattern 2 is arranged close to the four sides of the main pattern 1. FIG. 7B is a side sectional view of a phase shift mask having a transmission structure and an attenuation structure having a conventional structure. The conventional transmissive structure is a structure composed of the auxiliary pattern 2 made of the light-shielding portion 110 and the main pattern 1, and the main pattern 1 forms a concave portion in the depth direction on the exposed transparent substrate surface 10. That is, the part of the auxiliary pattern 2 is a non-phase shift transparent part, and the part of the main pattern 1 is a phase shift transparent part. Further, the conventional attenuation type structure has a non-phase shift transparent portion without forming a recess in the portion of the pattern 1, and a phase control layer 410 is formed in the pattern portion in the portion of the auxiliary pattern to thereby make the phase shift transparent. The part. On the other hand, FIG. 7C is a side sectional view of a phase shift mask having a transmission structure having the structure of the present invention. The transmission type structure of the present invention has two types, A and B. The A type is a structure consisting of the auxiliary pattern 2 made of the light shielding portion 110 and the main pattern 1, and this pattern 1 is directly under the exposed transparent substrate surface 10. In addition, the phase shift portion 140 is formed by the method of the present invention. That is, the part of the auxiliary pattern 2 is a non-phase shift transparent part, and the part of the main pattern 1 is a phase shift transparent part. The second type is the opposite. FIG. 7 (d) shows the damping structure of the present invention. The portion of the pattern 1 is a non-phase shift transparent portion without forming a recess, and the phase shift portion 140 is a region 3 between the pattern 1 and the auxiliary pattern 2 in the region immediately below the transmittance control layer 310 by the method of the present invention. To form a phase shift transparent portion.

  A fifth embodiment of the present invention is shown in FIG. FIG. 8A is a plan view of a phase shift mask by edge enhancement, and the transparent portion pattern 3 is arranged adjacent to the four peripheral portions of the pattern 1. FIG. 8B is a side sectional view of a phase shift mask having a transmission structure having a conventional structure and an attenuator-type or attenuator-type attenuation structure. The conventional transmission structure is a structure composed of the transparent pattern 3 made of the transparent substrate 1 and the main pattern 1, and the pattern 1 forms a recess in the exposed transparent substrate surface 10 in the depth direction. That is, the part of the transparent pattern 3 is a non-phase shift transparent part, and the part of the present pattern 1 is a phase shift transparent part. Further, in the conventional attenuation type structure, the former is a non-phase shift transparent part without forming a recess in the part of the pattern 1, and the transparent pattern 3 is provided on the surface of the transparent pattern 3 and the light shielding part 110. A phase control layer 410 was formed to form a phase shift transparent portion. The second type is the one in which the formation order of the light-shielding part 110 and the phase control layer 410 is reversed, and exhibits the same phase shift effect. On the other hand, FIG. 8C is a side sectional view of a phase shift mask having a transmission structure and an attenuation structure having the structure of the present invention. The transmissive structure of the present invention is a transparent pattern 3 made of a transparent substrate 1 and a structure made of the present pattern 1, and this pattern 1 is directly below the exposed transparent substrate surface 10 by the method of the present invention. Form. That is, the part of the transparent pattern 3 is a non-phase shift transparent part, and the part of the present pattern 1 is a phase shift transparent part. In the attenuation type structure of the present invention, the portion of the pattern 1 is formed as a non-phase shift transparent portion immediately below the transparent pattern 3 without forming the phase shift portion 140 by the method of the present invention. A portion 140 was formed as a phase shift transparent portion.

  A sixth embodiment of the present invention is shown in FIG. FIG. 9A is a plan view of a chromeless phase shift mask, in which only this pattern 1 is arranged. FIG. 9B is a side sectional view of a phase shift mask having a transmission structure and an attenuation structure having a conventional structure. The conventional transmissive structure is a structure comprising the main pattern 1 on the transparent substrate 10, and the main pattern 1 forms a concave portion in the depth direction on the exposed transparent substrate surface 10. That is, the part of the transparent substrate 10 is a non-phase shift transparent part, and the part of the pattern 1 is a phase shift transparent part. Further, in the conventional attenuation type structure, the phase control layer 410 is formed in the portion of the pattern 1 to form a phase shift transparent portion, and the phase shift transparent portion is formed in the portion of the transparent substrate 10. On the other hand, FIG. 9C is a side sectional view of a phase shift mask having a transmission structure having the structure of the present invention. The transmissive structure of the present invention is a structure comprising the main pattern 1, and the main pattern 1 forms the phase shift portion 140 immediately below the exposed transparent substrate surface 10 by the method of the present invention. That is, the part of the transparent substrate 10 is a non-phase shift transparent part, and the part of the pattern 1 is a phase shift transparent part.

  According to such a pattern transfer method, pattern exposure can be performed with high accuracy on the resist formed on the transfer substrate, and as a result, patterns of semiconductors and the like can be manufactured with a high yield.

1 is a structural cross-sectional view of a first embodiment of a phase shift photomask of the present invention. Explanatory drawing which shows the manufacturing process of 1st Example of the phase shift photomask of this invention. The structure sectional view of the 2nd example of the phase shift photomask of the present invention. Explanatory drawing which shows the manufacturing process of 2nd Example of the phase shift photomask of this invention. Sectional drawing of structure of 3rd Example of the phase shift photomask of this invention. The manufacturing process of 3rd Example of the phase shift photomask of this invention. 4 shows a fourth embodiment of the phase shift photomask of the present invention. 5 shows a fifth embodiment of the phase shift photomask of the present invention. 6 shows a sixth embodiment of the phase shift photomask of the present invention. 4 is a side cross-sectional view illustrating the structure of a phase shift portion of the phase shift photomask of the present invention. FIG. FIG. 6 is a cross-sectional structure diagram for explaining a conventional transmission type phase shift mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main pattern 2 ... Auxiliary pattern 3 ... Transparent pattern 100 ... Phase shift mask 10 ... Transparent substrate (transparent material)
DESCRIPTION OF SYMBOLS 110 ... Light-shielding part 110A ... Pattern part 110B ... Non-phase shift transparent part 110C ... Phase shift transparent part 140 ... Phase shift part 140A ... Phase shift part 150 of recessed part formation ... Opening width 200 ... Electron beam or photosensitive resin (resist)
210A ... resist pattern part 210B ... non-phase shift transparent part resist pattern part 210C ... phase shift transparent part resist pattern part 310 ... transmittance control layer 310A ... transmittance control part (pattern)
310B ... Non-phase shift transparent part 310C ... Phase shift transparent part 410 ... Phase control layer

Claims (9)

  A phase shift mask having a refractive index changing portion inside a transparent substrate, wherein a phase difference between transmitted light transmitted through the refractive index changed portion and transmitted light transmitted through the transparent substrate is approximately 180 degrees. .   2. The phase shift mask according to claim 1, wherein the refractive index changing portion has a high refractive index or a low refractive index with respect to the refractive index of the transparent substrate itself.   The phase shift mask according to claim 1, wherein the refractive index changing portion is formed of a transparent substrate having a high density or a vacuum hole.   In a method of manufacturing a phase shift mask having a refractive index changing portion inside a transparent substrate, wherein a phase difference between transmitted light transmitted through the refractive index changed portion and transmitted light transmitted through the transparent substrate is approximately 180 degrees. The method of manufacturing a phase shift mask, wherein the refractive index changing portion is formed by laser ablation that converges and expresses laser light at the position inside the transparent substrate. 5. The method of manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is a femtosecond (1 × 10 ⁻¹⁵ seconds) pulse laser. 5. The method of manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is an attosecond (1 × 10 ⁻¹⁸ second) pulse laser. 5. The method of manufacturing a phase shift mask according to claim 4, wherein the laser ablation laser is a zept second (1 × 10 ⁻²¹ second) pulse laser. 5. The method of manufacturing a phase shift mask according to claim 4, wherein the laser of the laser ablation is a joctosecond (1 × 10 ⁻²⁴ second) pulse laser.   4. A pattern transfer method for improving resolution by using the phase difference of a phase shift mask, wherein a pattern is formed on a transfer substrate by exposure transfer using a photolithography method using the phase shift mask according to any one of claims 1 to 3. A pattern transfer method characterized by forming.

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