TW201324029A - Photomask - Google Patents

Abstract

The present invention provides a photomask used for improving a photolithography process window of semiconductor design elements, comprising: a transparent substrate; a plurality of light-shielding patterns spaced at interval and disposed on the surface of the transparent substrate for blocking an exposure light source; and a plurality of light transmissive regions, defined by the light-shielding patterns, allowing the exposure light source to pass through. More particularly, the light-shielding patterns have different thicknesses. By means of utilizing a photomask having light-shielding layers of at least two thicknesses, the exposure light source generates different optical phenomena because of different optical path lengths generated when the exposure light source passes through the light transmissive regions of the photomask, so as to form focal planes of different depths on a photoresist layer, thereby improving the problem of photoresist pattern deformation and distortion occurred after the exposure development of the photoresist layer, and thus expanding the photolithography process window.

Description

Mask

The present invention relates to a reticle, and more particularly to a reticle having different opaque layer thicknesses for different semiconductor design pattern sizes or semiconductor design pattern loading to enhance the lithography process space.

As the density of electronic circuit components continues to increase, semiconductor lithography imaging technology continues to evolve to meet the need to produce more detailed images. Increasing the depth of focus (DOF) to increase the lithography process window can help reduce the rework rate and yield loss of the product, and improving the resolution is also an important issue in lithography. There are many ways to increase the resolution, such as using a lens with a larger numerical aperture or using a shorter wavelength exposure source, from the past I-line (wavelength = 365 nm) to the present Widely used deep ultraviolet KrF (wavelength = 248 nm), and ArF (wavelength = 193 nm), in addition, phase shift mask, off-axis illumination and other technologies can also enhance the analytical capabilities.

Generally, in the fabrication of a semiconductor device, it is necessary to separately pattern the photoresist on the wafer by using a plurality of mask processes, and to become, for example, a mask before the etching or ion implantation step. Referring to FIG. 1 and FIG. 2, FIG. 1 shows a binary mask 1 which is currently used to form different line densities, and a photoresist pattern 102 formed on a wafer 100 after being exposed by the mask 1, and FIG. 2 It is a schematic diagram of a lithography exposure system 200 and a position relative to the reticle 1. The structure of the reticle 1 includes a substrate 11 and a predetermined pattern 12 having a plurality of metal light shielding layers 121 which are alternately arranged and substantially the same in thickness, and a plurality of which are jointly defined by the adjacent two light shielding layers 121. Light transmissive area 122. After the preset pattern 12 is designed and fabricated on the reticle 1, the reticle 1 is placed in the lithography exposure system 200 by using a lithography exposure system 200 as shown in FIG. After the light source 201 is irradiated, the predetermined pattern 12 can be transferred to the photoresist layer 101 on the wafer 100, and then the exposed photoresist layer 101 is subjected to post exposure bake (PEB) and developed. The photoresist layer 101 on the wafer 100 can be patterned into a specific photoresist pattern 102 having a line 103 and a shape similar to the shape of the light shielding layer 121 of the mask 1 . The gap 104 of the light transmitting region 122 should be.

Wherein, the preset pattern 12 on the reticle 1 is imaged by a exposure light source and is imaged on a Focal plane on the opposite side of the lens. When the focus plane overlaps with an optimal photoresist plane, After the hardening and developing steps, the photoresist pattern 102 having the best resolution is obtained. However, because the quality of the focusing lens is not good or the exposure light source is irradiated to the photoresist layer 101 through the light transmitting regions 122, the density of the light transmitting regions 122 may be different or the exposed photoresist may be In the subsequent processes such as PEB, the photoresist layer 101 generates different concentrations of photoacids in the same focal plane due to the difference in the degree of diffusion of hydrogen ions, so that the photoresist patterns formed in different line density regions may have inconsistent photoresistive behavior. A resolution problem; or a diffraction phenomenon caused by light rays passing through the light-transmitting regions 122 adjacent to the edges of the light-shielding layers 121, so that the light intensity between the light-transmitting regions 122 and the light-shielding layer 121 is compared Decrease, causing pattern distortion after development; or because the surface of the wafer is uneven, the thickness of the photoresist formed on the wafer is not uniform, and after exposure, the exposure light source passing through the mask focuses on the same photoresist On the horizontal surface, therefore, for different thicknesses of the photoresist layer 101, it is easy to cause a problem of resolution in which the photoresist pattern formed after development is inconsistent, or the partial pattern may be aggregated when aligned. Depth variation or defocus causes a problem that the line width variation exceeds the specification range, the edge roughness deteriorates, or the photoresist cross-sectional profile becomes poor, resulting in, for example, a line formed in a high line density region as shown in FIG. 3A. 103 has a top area that is too small, has insufficient height, or has a rounding at the end of the line 103 as shown in FIGS. 3B and 3C, or a footing profile at the end, or because of a gap formed. The critical dimension error of 104 causes the gap 104 to create a development pattern distortion problem such as necking.

Traditionally, in the efforts to solve the post-development pattern distortion caused by out-of-focus, some have been improved for lithography equipment, and some factors that may cause the defocusing process in the exposure process to construct a system for immediate detection and feedback correction, in addition, currently In the semiconductor process, before the lithography exposure is determined, the product wafer is first selected for measurement of the Focus Exposure Matrix to determine the optimum process focal length value. However, among the many methods disclosed, there is still no good improvement in the problems of poor resolution of development or defocusing of micro-areas due to differences in line density or unevenness in structure of the same wafer.

Accordingly, it is an object of the present invention to provide a reticle that enhances the lithography process space by providing a pattern loading design for different semiconductor design patterns or semiconductor designs.

Further, another object of the present invention is to provide a photomask for improving the distortion distortion of a photoresist pattern formed after exposure and development of a photoresist layer.

Therefore, the photomask of the present invention is used to form a photoresist pattern corresponding to a semiconductor component line, comprising a light transmissive substrate, a plurality of light shielding patterns, and a plurality of light transmissive regions.

The light-transmitting substrate allows the exposure light source to pass through, and the light-shielding patterns are spaced apart from the surface of the light-transmissive substrate to block the exposure light source so that the energy of the light passing through the light-shielding patterns is lower than the photosensitive energy of the photoresist. The light transmissive region is defined by the light shielding patterns, allowing the exposure light source to pass through to make the photoresist photosensitive, and the light shielding patterns collectively constitute the photoresist pattern to be formed, and have at least two thicknesses.

In addition, the photomask of the present invention comprises a light transmissive substrate, a light shielding unit, and a plurality of light transmissive regions.

The light-transmitting substrate allows the exposure light source to pass through, and the light-shielding unit is disposed on the surface of the light-transmitting substrate to block the exposure light source, so that the energy of the light passing through the light-shielding unit is lower than the light-resisting photosensitive energy, and the light-transmitting regions The light blocking unit is defined by the light shielding unit and allows the exposure light source to pass through, wherein the light shielding unit has a plurality of first light shielding patterns arranged at intervals, and each of the first light shielding patterns has at least two different thickness.

The effect of the invention is that the reticle having the light shielding pattern of at least two thicknesses causes the exposure light source to generate different optical phenomena when passing through the light transmitting region of the reticle and form a focusing plane of different depths in the photoresist layer. The invention is used to improve the distortion of the photoresist pattern formed by the photoresist layer after exposure and development, and the lithography process space can be enlarged.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of FIG.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

The reticle of the present invention may be a reticular reticle, that is, the circuit pattern on the reticle may be transferred to a wafer 100 having a photoresist layer 101 as shown in FIG. 1 by a ratio of 5:1 or 4:1. After the development process, the photoresist layer 101 is formed into a photoresist pattern identical to that of the subsequent circuit structure to be transferred onto the wafer 100. It is to be noted that the pattern of the reticle is formed according to the circuit pattern design finally formed on the wafer 100, for example, the line density is different, or according to the difference in the constituent materials of the wafer 100, the surface morphology difference, and the like. Shading patterns with different Proximity or linearity are therefore not limited as shown in the figure.

The photoresist pattern is used in the lithography exposure system 200, and the reticle is placed in the lithography exposure system 200 and illuminated by an exposure light source 201 to cause the photoresist layer to pass through the exposure light source 201 of the reticle. The local area of 101 is sensitized, and finally the photosensitive photoresist layer 101 is subjected to a development process.

The lithography exposure system 200 is a stepper or a scanning stepper using optical projection technology, including concentrating the exposure light source 201 to the focusing lens 202 of the reticle, and imaging the pattern on the reticle onto the wafer 100. The projection lens 203 or the like can use deep ultraviolet light (DUV) having a wavelength of 248 nm or 193 nm, or even deep ultraviolet light (EUV). The photomasks in the following embodiments are all transferred to the wafer 100 in a 4:1 manner for illustration.

Referring to FIG. 4, a first preferred embodiment of the present invention provides a photomask 3 for forming a photoresist pattern having a same line density on a photoresist layer overlying a wafer. .

The predetermined photoresist pattern has a plurality of lines spaced apart from each other and composed of a photoresist material, and a plurality of spaces defined by the lines, the mask 3 having a photoresist pattern Corresponding to the light shielding pattern 32, and the reticle 3 shown in FIG. 4 is only a display portion structure.

The reticle 3 includes a transparent substrate 31, a plurality of light shielding patterns 32, and a plurality of light transmitting regions 33.

The light-shielding pattern 32 has a plurality of first light-shielding layers 321 and second light-shielding layers 322 which are spaced apart from each other and are alternately formed on the light-transmissive substrate 31, and can block the exposure light source 201 to penetrate the first The light of the two light-shielding patterns 321 and 322 is lower than the light-receiving energy of the photoresist layer, and each of the light-transmitting regions 33 is defined by an adjacent first light-shielding layer 321 and a second light-shielding layer 322, allowing The exposure light source 201 passes through to expose the photoresist layer, and the first light shielding layer 321 and the second light shielding layer 322 have different thicknesses.

It should be noted that the definition of the pitch refers to the width of one line of the formed photoresist pattern plus the width of a space adjacent thereto, in this embodiment, on the wafer. The pitch between the patterns to be formed is less than 140 nm. Therefore, under the pattern design of the reticle, each of the first light shielding layers 321 and each of the second light shielding layers 322 and the respective The spacing defined by the adjacent one of the light transmitting regions 33 is less than 560 nm.

Further, the light shielding patterns 32 may completely or partially block the penetration of the exposure light source 201, and the material thereof may be selected from the group consisting of: MoSi, ToSi ₂ , Nb ₂ O ₅ , MoO ₃ , MoN, Cr ₂ O ₃ , TiN, ZrN, TiO ₂ , TaN, Ta ₂ O ₅ , SiO ₂ , NbN, Si ₃ N ₄ , ZrN, Al ₂ O ₃ N, MoSi, MoSiN, MoSiON, MoSiO, CrOC, CrONC, Cr, Mo, Ti, Ta, Iron oxide, inorganic material, or a combination of these.

The light-transmitting substrate 31 is made of a material that allows penetration of deep ultraviolet light, for example, made of quartz glass (Quartz), and the size of the light-shielding patterns 32 in the mask process, for example, line width uniformity (CD uniformity), Chromium thickness uniformity or chrome film profile (Edge profile), etc., need to be tightly controlled within the specification range. Preferably, the height of the light shielding pattern 32 is between 5~ Between 200 nm (nm), and the difference between the first light shielding layer 321 and the second light shielding layer 322 is not less than 20 .

When the exposure light source 201 passes through the reticle 3, since the light-transmitting regions are defined by the first and second light-shielding layers 321, 322 having different thicknesses, when light passes through each of the light-transmitting regions 33, Adjacent to the edges of the first and second light shielding layers 321 and 322, different diffraction phenomena may be generated, and the light transmitting region 33 and the first and second light shielding layers 321 and 322 adjacent to the light transmitting region 33 may be changed. The light intensity contrast can be used to correct the conventional surface light source 201, which is easily formed in the high-density line region due to the diffraction phenomenon after passing through the reticle having the same thickness of the light-shielding pattern 121, and the top surface area is insufficient. Or there is a problem of shortening, which can correct the formed photoresist pattern and increase the tolerance of the exposure and development process.

It is worth mentioning that the light shielding patterns 32 can also be designed and modified by using an auxiliary line or by an optical proximity correction technique, and the mask 3 can also be a phase shift mask or a binary light. cover.

In addition, it is to be noted that the width of the line and the space of the photoresist pattern may vary depending on the circuit density of the circuit structure expected to be formed on the wafer. In other words, the light-shielding pattern 32 and the light-transmitting region 33 of the reticle 3 are also designed to have different widths corresponding to the photoresist pattern to be formed, and the light-shielding patterns 32 can be corresponding to the light-transmitting regions 33 of different widths. Different thickness performances can be used to correct the pattern of different line densities formed.

A second preferred embodiment of the present invention provides a reticle 4 for forming a predetermined photoresist pattern on a photoresist layer overlying a wafer. In the preferred embodiment, the photoresist pattern has a plurality of lines spaced apart from each other and composed of a photoresist material and a plurality of spaces defined by the lines.

Referring to Figure 5, there is shown a bottom perspective view of the reticle 4 of the second preferred embodiment.

The reticle 4 includes a light transmissive substrate 41, a plurality of light shielding patterns 42, and a plurality of light transmissive regions 43.

The light shielding patterns 42 are disposed on the transparent substrate 41 at intervals, and the exposure light source 201 is blocked to make the energy of the light passing through the light shielding pattern 42 lower than the photosensitive energy of the photoresist layer. The constituent materials of the light substrate 41 and the light shielding patterns 42 are the same as those of the first preferred embodiment, and thus will not be described again.

Each of the light shielding patterns 42 has a first light shielding layer 421 connected to the surface of the transparent substrate 41, and a first portion extending from a central position of the surface of the first light shielding layer 421 away from the transparent substrate 41. The light shielding layer 422 is defined by the light shielding pattern 42 to allow the exposure light source 201 to pass through to make the photoresist layer sensitive; preferably, each of the light shielding patterns 42 is adjacent to the light shielding layer 42 The spacing defined by a light transmissive region 43 is less than 560 nm.

The second light-shielding layer 422 may be selected from a material having a different etching selectivity than the first light-shielding layer 421, for example, the first light-shielding layer 421 may be selected from chrome, and the second light-shielding layer 422 may be used. It is selected from tantalum nitride (TaN). In this manner, the second light shielding layer 422 can serve as a hard mask when patterning etching of the first light shielding layer 421 is performed by using an appropriate etching reaction gas, and the second light shielding layer 422 is patterned. When etching, the first light shielding layer 421 under it may be a termination layer of the etching signal. In addition, the material of the second light shielding layer 422 may be the same material as the first light shielding layer 421, for example, all are metal chromium films, but precise etching time control is required during the etching process to form a film. The required thickness and three-dimensional shape. For the size of the light-shielding patterns 42 in the mask process, for example, CD uniformity, Chromium thickness uniformity or chrome film profile profile, etc., need to be tightly controlled. Preferably, the height of the light shielding patterns 42 is between 5 and 200 nanometers (nm), and the difference between the first light shielding layer 421 and the second light shielding layer 422 is not less than 20 .

When the exposure light source 201 passes through the reticle 4, the light shielding pattern 42 is transferred to the photoresist layer, and then after the PEB and the development step, the photoresist layer is formed to have a plurality of strips and the first A line corresponding to the light-shielding pattern 42 and a plurality of photoresist patterns corresponding to the light-transmitting regions 43 and having no space in which the photoresist material exists.

In this case, the difference in thickness between the first light shielding layer 421 and the second light shielding layer 422 of the light shielding pattern 42 is such that the light passing through the light transmission region 43 produces different windings adjacent to the edges of the first and second light shielding layers 421 and 422. Shooting phenomenon, increasing the contrast of the light intensity, and for finely adjusting the distance between the reticle 4 and the projection lens 203, so that the light rays generate different depths of focus plane in the photoresist layer, thereby improving the conventional light through the In the case of the light-transmitting region 122, the light intensity of the light-shielding layer 121 and the light-transmitting region 122 is reduced due to the diffraction effect, and because the photoresist layer is in a subsequent process such as PEB, the degree of diffusion of photoacid is different. The photoresist layer produces different concentrations of photoacid on the same focal plane, resulting in a necking of the developing pattern distortion problem, and the tolerance of the exposure and development process can be improved.

Referring to FIG. 6 , the first light shielding patterns 42 may further have at least one third light shielding layer 424 extending from the two end portions 423 of the first light shielding layer 421 to form different layers as shown in FIG. 6 . The light-shielding units 42a, 42b, and 42c are disposed separately or in combination with the semiconductor circuit design, so that the light-shielding patterns 42 are thickened by the light-shielding units 42a, 42b, and 42c. The difference is that the conventional circuit formed by the photoresist layer after exposure and development has a problem that the development pattern is distorted due to a decrease in light intensity contrast due to diffraction.

In addition, referring to FIG. 7, when a light-shielding pattern on a photomask is used to form a recess in a photoresist layer, the light-shielding patterns 42 shown in FIG. 5 and FIG. 6 may be combined to obtain a pattern. The mask 4' of the light-shielding pattern 42' shown in Fig. 7 is a bottom perspective view of the mask 4'.

The reticle 4 ′ has a rectangular transparent area 43 ′, and the opaque pattern 42 ′ has a first light shielding layer 421 ′ connected to the transparent substrate 41 and surrounding the transparent area 43 ′. a third light shielding layer 424 ′ of two opposite sides of the first light shielding layer 421 ′, and a second light shielding layer 422 ′ extending from an intermediate position of the first light shielding layer 421 ′ corresponding to the light transmission region 43 ′ The center and the two opposite sides of the light-shielding pattern 42' have a large thickness, thereby improving the critical dimension error of the groove after the exposure is formed and the problem of rounding of the periphery of the formed groove. It should be noted that when the size of the groove to be formed is small, the second light shielding layer 422 ′ may not be formed again, that is, the two light shielding patterns 42 ′ need to be disposed in two pairs corresponding to the light transmitting area 43 ′. The side has a large thickness.

Referring to FIG. 8 , a third preferred embodiment of the present invention provides a photomask 5 including a transparent substrate 51 , a plurality of light shielding patterns 52 , and a plurality of light transmissive regions 53 .

Each of the light shielding patterns 52 has a first light shielding layer 521 connected to the surface of the transparent substrate 51 and having a first thickness T1, and a first light shielding layer 521 extending from one side of the light shielding substrate 51. And a second light shielding layer 522 connected to the surface of the transparent substrate 51, the second light shielding layer has a second thickness T2 and the second thickness T2 is smaller than the first thickness T1, and the plurality of light transmission regions 53 have a plurality of a light transmitting region 531 and a plurality of second light transmitting regions 532, and each of the first light transmitting regions 531 is jointly defined by two adjacent first light shielding layers 521, and each of the second light transmitting regions 532 It is defined by two adjacent second light shielding layers 522, and any one of the light shielding patterns 52 defines a first spacing S1 with an adjacent first light transmitting region 531, and any one of the light shielding patterns 52 and the adjacent one. The second light transmitting region 532 defines a second pitch S2 different from the second pitch S2, and the first and second pitches S1 and S2 are not more than 560 nm. Preferably, the height of the light shielding patterns 52 is between 5 and 200 nanometers (nm), and the difference between the first light shielding patterns 521 and the second light shielding patterns 522 is not less than 20 .

Using the difference in thickness between the first light shielding layer 521 and the second light shielding layer 522 of the light shielding patterns 52, the light passing through the first and second light transmitting regions 531 and 532 having different widths is adjacent to the first light shielding layer 521. And the edge of the second light shielding layer 522 generates different diffraction effects, so that the intensity contrast between the first and second light transmitting regions 531 and 532 and the first and second light shielding layers 521 and 522 is different, but The improvement is conventionally caused by the diffraction of the light passing through the light-transmitting region 122, so that the region of the photoresist layer corresponding to the position of the light-shielding layer 121 is also absorbed by the light exposure, so that the subsequent corresponding formed lines are deformed at the top, and the surface area is insufficient. Or there is a problem of shorting, which can correct the formed line pattern and increase the tolerance of the exposure and development process.

In addition, it is to be noted that the light-shielding patterns 42 shown in FIG. 5 and the light-shielding patterns 52 shown in FIG. 8 can be simultaneously applied to the same mask for the layout design of the photoresist pattern lines.

In summary, the reticle of the present invention mainly achieves different depths of focus by forming a light shielding pattern (first and second light shielding layers) having at least two thicknesses, not only fine-tuning the distance between the reticle and the projection lens. The purpose of the plane is to correct the difference in development resolution of the formed photoresist pattern, and at the same time utilize the difference in thickness of the light-shielding patterns, so that the light passing through the light-transmitting region is different in the edge adjacent to the light-transmitting regions. The diffraction effect causes a difference in the light intensity contrast between the light-transmitting region and the light-shielding pattern adjacent to the light-transmitting region, which can improve the conventional diffraction effect of light passing through the light-transmitting region 122. The resulting problem of distortion of the developed pattern can increase the tolerance of the exposure and development process and expand the focus processing space.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

200. . . Photolithography system

201. . . Exposure light source

202. . . Wafer

203. . . Focusing lens

204. . . Projection lens

3. . . Mask

31. . . Light transmissive substrate

32. . . Shading pattern

321. . . First light shielding layer

322. . . Second light shielding layer

33. . . Light transmission area

4. . . Mask

41. . . Light transmissive substrate

42. . . Shading pattern

421. . . First light shielding layer

422. . . Second light shielding layer

423. . . Ends

424. . . Third light shielding layer

43. . . Light transmission area

4’. . . Mask

42’. . . Shading pattern

421’. . . First light shielding layer

422’. . . Second light shielding layer

424’. . . Third light shielding layer

43’. . . Light transmission area

5. . . Mask

51. . . Light transmissive substrate

52. . . Shading pattern

521. . . First light shielding layer

522. . . Second light shielding layer

53. . . Light transmission area

531. . . First light transmission zone

532. . . Second light transmission zone

T1. . . First thickness

T2. . . Second thickness

S1. . . First spacing

S2. . . Second spacing

Figure 1 is a partial cross-sectional view showing a conventional binary reticle structure;

Figure 2 is a schematic view showing the lithography exposure system and its relative relationship with the reticle;

3A-3C are schematic views illustrating a state of development distortion of a photoresist pattern formed by a conventional binary mask;

Figure 4 is a partial cross-sectional view showing the first preferred embodiment of the reticle of the present invention;

Figure 5 is a bottom perspective view showing a second preferred embodiment of the photomask of the present invention;

Figure 6 is a partial perspective view showing different embodiments of the light shielding pattern of Figure 4;

Figure 7 is a bottom perspective view showing the reticle pattern for forming a groove; and

Figure 8 is a partial cross-sectional view showing a third preferred embodiment of the present invention.

3. . . Mask

31. . . Light transmissive substrate

32. . . Shading pattern

321. . . First light shielding layer

322. . . Second light shielding layer

33. . . Light transmission area

Claims (18)

A photomask for forming a photoresist pattern corresponding to a semiconductor component line, comprising: a transparent substrate for allowing the exposure light source to pass; and a plurality of light shielding patterns arranged at intervals on the surface of the transparent substrate to block the exposure The light source is such that the energy of the light passing through the light-shielding patterns is lower than the light-receiving light energy, the light-shielding patterns collectively forming the photoresist pattern to be formed, and having at least two thicknesses; and a plurality of light-transmitting regions, The shading patterns define that the exposure light source is allowed to pass to sensitize the photoresist. The reticle according to claim 1, wherein the two adjacent light shielding patterns have different thicknesses and the thickness difference is not less than 20 . The reticle according to claim 1 or 2, wherein the opaque patterns have a thickness of 5 to 200 nm. The reticle according to claim 1, wherein any one of the light shielding patterns defines a spacing together with a width of the adjacent one of the light transmitting regions, and the spacing is not more than 560 nm. The reticle of claim 1 or 2, wherein at least one of the light shielding patterns has at least two thicknesses and a thickness difference of not less than 20 . The reticle of claim 1, wherein the reticle is a phase shift reticle. A reticle according to claim 1, wherein the reticle is a binary reticle. A light cover comprising: a transparent substrate for allowing an exposure light source to pass; a light shielding unit disposed on the surface of the transparent substrate to block the exposure light source so that the energy of light passing through the light shielding unit is lower than the light resistance Photosensitive energy, the light shielding unit has a plurality of first light shielding patterns spaced apart from each other, and each of the first light shielding patterns has at least two different thicknesses: and a plurality of light transmitting regions defined by the light shielding unit and allowed The light source is passed through to expose the photoresist. The photomask of claim 8, wherein each of the first light shielding patterns has a first light shielding layer connected to the surface of the transparent substrate, and a portion away from the substrate from the first light shielding layer. The second light shielding layer extends from the middle of the surface of the first light shielding layer, and the thickness difference between the first and second light shielding layers is not less than 20 . The reticle of claim 8 or 9, wherein each of the first light shielding patterns has a first light shielding layer connected to the surface of the transparent substrate and a surface formed on the surface of the first light shielding layer a third light shielding layer, the surface of the first light shielding layer has two ends that are relatively far apart, and the third light shielding layer is extended by at least one end portion thereof away from the surface of the first light shielding layer, and the first light shielding layer is The thickness difference of the third light shielding layer is not less than 20 . The reticle of claim 8, wherein any one of the first light-shielding patterns and the width of the adjacent light-transmitting regions define a pitch which is not more than 560 nm. The reticle of claim 8 , wherein each of the first light shielding patterns has a first light shielding layer connected to the surface of the transparent substrate and having a first thickness and a first light shielding layer a second light shielding layer extending adjacent to one side of the substrate and connected to the surface of the transparent substrate, the second light shielding layer having a second thickness and the second thickness being smaller than the first thickness, the light transmission regions having a plurality of first light transmitting regions and a plurality of second light transmitting regions, wherein each of the first light transmitting regions is jointly defined by two adjacent first light shielding layers, and each of the second light transmitting regions is Adjacent two second light shielding layers are collectively defined. The reticle of claim 12, wherein any one of the first light-shielding patterns and the adjacent one of the first light-transmitting regions define a first pitch, and any one of the second light-shielding patterns and the adjacent one The second light transmissive regions collectively define a second pitch, the first pitch being different from the second pitch, and the first and second pitches are each no greater than 560 nm. The reticle of claim 10, wherein the opaque unit further has a plurality of second opaque patterns, each of the second opaque patterns having a first thickness connected to the surface of the transparent substrate a fourth light shielding layer and a fifth light shielding layer extending from the one side of the substrate and connected to the surface of the transparent substrate, the fifth light shielding layer having a second thickness and the second thickness The first light-transmissive region has a plurality of first light-transmitting regions, a second light-transmitting region, and a third light-transmitting region, and the first light-transmitting regions are jointly defined by the first light-shielding patterns. Each of the second light-transmissive regions is defined by two adjacent fourth light-shielding regions, and each of the third light-transmitting regions is jointly defined by two adjacent fifth light-shielding layers. The reticle of claim 14, wherein any one of the second light-shielding patterns and the adjacent one of the first light-transmitting regions define a first pitch, and any one of the second light-shielding patterns and the adjacent one The second light transmissive regions collectively define a second pitch, and the first pitch is different from the second pitch. The reticle according to claim 15, wherein the first and second spacings are not more than 560 nm, and the difference between the thickness of the fourth light shielding layer and the fifth light shielding layer is not less than 20 . The reticle of claim 8 wherein the reticle is a phase shift reticle. The reticle of claim 8 wherein the reticle is a binary reticle.