Preparation method of photomask and photomask

Abstract

The invention provides a preparation method of a photomask and the photomask, and relates to the technical field of semiconductor manufacturing, and the preparation method of the photomask comprises the steps that a substrate is provided, the substrate comprises a base, a semi-transparent layer and a light shielding layer which are sequentially stacked, the substrate is provided with a first area and a second area, and in the same patterning process, the semi-transparent layer and the light shielding layer are sequentially stacked; a first sub-photomask is formed in the first area, a second sub-photomask is formed in the second area, and the first sub-photomask is different from the second sub-photomask. According to the method provided by the invention, the preparation process for preparing different first sub photomasks and second sub photomasks on the same substrate is simplified, so that the production cost for manufacturing the mixed photomask is saved.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor manufacturing technology, and in particular to a method for preparing a photomask and a photomask. Background Art

[0002] The photolithography process is an important step in the semiconductor device manufacturing process. In the photolithography process, a patterned mask is used to expose a photoresist layer, and then a pattern identical to the mask is formed on the photoresist layer through development. However, the process of making a mask in the related art is complicated and costly. Summary of the invention

[0003] The following is a summary of the subject matter of the detailed description of the present disclosure. This summary is not intended to limit the scope of the claims.

[0004] The present invention provides a method for preparing a photomask and the photomask.

[0005] According to some embodiments, a first aspect of the present disclosure provides a method for preparing a photomask, the method comprising:

[0006] Providing a substrate, the substrate comprising a base, a semi-transmissive layer and a light shielding layer stacked in sequence, the substrate having a first area and a second area;

[0007] In the same patterning process, a first sub-mask is formed in the first region, and a second sub-mask is formed in the second region, wherein the first sub-mask is different from the second sub-mask.

[0008] According to some embodiments of the present disclosure, in the same patterning process, forming a first sub-mask in the first region and forming a second sub-mask in the second region include:

[0009] The same patterning process includes a first patterning process and a second patterning process, through which the light shielding layer and the semi-transparent layer located in the first area and the second area are subjected to a first patterning process, a first pattern is formed in the light shielding layer located in the first area and the second area, and a second pattern is formed in the semi-transparent layer located in the first area and the second area;

[0010] Through the second patterning process, the first graphic located in the first area is subjected to a second patterning process to form a third graphic, and the second graphic located in the first area, the first graphic located in the second area, and the second graphic located in the second area are not subjected to patterning process.

[0011] According to some embodiments of the present disclosure, the first graphic located in the first area is subjected to a second patterning process to form a third graphic, and the second graphic located in the first area, the first graphic located in the second area, and the second graphic located in the second area are not subjected to patterning process, including:

[0012] Coating a photoresist on the first patterned light shielding layer located in the first area and the second area and on the surface of the substrate, wherein the surface of the substrate is a portion exposed by the first pattern and the second pattern;

[0013] The third pattern is defined on the photoresist located in the first area, and no pattern is defined on the photoresist located in the second area;

[0014] Using the photoresist having the third pattern as a mask, etching the first patterned light shielding layer located in the first area to form the third pattern in the light shielding layer located in the first area;

[0015] The photoresist is removed.

[0016] According to some embodiments of the present disclosure, defining the third pattern on the photoresist located in the first area, and not defining a pattern on the photoresist located in the second area, includes:

[0017] forming a first mark in the first area and forming a second mark in the second area;

[0018] The photolithography equipment identifies the first mark and the second mark, patterns the photoresist located in the first area corresponding to the first mark, forms a third pattern in the photoresist located in the first area, and does not pattern the photoresist located in the second area corresponding to the second mark.

[0019] According to some embodiments of the present disclosure, the first mark is a ring-shaped figure located in the first area and arranged around the edge of the first area; the second mark is a closed figure that fully covers the second area.

[0020] According to some embodiments of the present disclosure, the shapes of the first area and the second area are both rectangular; the first mark is a rectangular ring figure, and the second mark is a rectangular figure.

[0021] According to some embodiments of the present disclosure, the first graphic includes at least one first opening, the second graphic includes at least one second opening exposing the substrate, and the third graphic includes a third opening;

[0022] In the first region, the orthographic projection of the third opening on the substrate covers the orthographic projection of the second opening on the substrate, and the orthographic projection of the second opening on the substrate overlaps with the orthographic projection of the first opening on the substrate;

[0023] In the second region, an orthographic projection of the second opening on the substrate overlaps with an orthographic projection of the first opening on the substrate.

[0024] According to some embodiments of the present disclosure, the first graphic and the second graphic are the same; and / or

[0025] The orthographic projection of the first region on the substrate falls outside the orthographic projection of the second region on the substrate.

[0026] According to some embodiments of the present disclosure, the light shielding layer and the semi-transparent layer located in the first area and the second area are subjected to a first patterning process through the first patterning process, a first pattern is formed in the light shielding layer located in the first area and the second area, and a second pattern is formed in the semi-transparent layer located in the first area and the second area, including:

[0027] Coating a photoresist on the surface of the light shielding layer located in the first area and the second area;

[0028] patterning the photoresist to form a photolithographic pattern in the photoresist;

[0029] Using the photoresist having the photolithography pattern as a mask, etching the light shielding layer and the semi-transparent layer, forming the first pattern in the light shielding layer located in the first area and the second area, and forming the second pattern in the semi-transparent layer located in the first area and the second area;

[0030] The photoresist is removed.

[0031] According to some embodiments of the present disclosure, the light shielding layer and the semi-transparent layer located in the first area and the second area are subjected to a first patterning process through the first patterning process, a first pattern is formed in the light shielding layer located in the first area and the second area, and a second pattern is formed in the semi-transparent layer located in the first area and the second area, including:

[0032] Coating a photoresist on the surface of the light shielding layer located in the first area and the second area;

[0033] patterning the photoresist to form a photolithographic pattern in the photoresist;

[0034] Using the photoresist having the photolithography pattern as a mask, etching the light shielding layer to form the first pattern in the light shielding layer located in the first area and the second area;

[0035] Using the light shielding layer having the first pattern as a mask, etching the semi-transparent layer to form a second pattern in the semi-transparent layer located in the first area and the second area;

[0036] The photoresist is removed.

[0037] According to some embodiments of the present disclosure, the material of the light shielding layer includes metallic chromium or chromium oxide; and / or the material of the semi-transmissive layer includes at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN.

[0038] According to some embodiments of the present disclosure, the first sub-light mask includes the substrate, a semi-transparent layer located on the substrate and having the second pattern, and a light-shielding layer located on a side of the semi-transparent layer having the second pattern away from the substrate and having the third pattern; the second sub-light mask includes the substrate, a semi-transparent layer located on the substrate and having the second pattern, and a light-shielding layer located on a side of the semi-transparent layer having the second pattern away from the substrate and having the first pattern.

[0039] According to some embodiments, a second aspect of the present disclosure provides a mask, the mask comprising a substrate, the substrate comprising a base, a semi-transmissive layer and a light shielding layer stacked in sequence, the substrate having a first area and a second area;

[0040] A first sub-light mask is disposed in the first area, a second sub-light mask is disposed in the second area, and the first sub-light mask is different from the second sub-light mask.

[0041] According to some embodiments of the present disclosure, the material of the light shielding layer includes metallic chromium or chromium oxide; and / or the material of the semi-transmissive layer includes at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN.

[0042] According to some embodiments of the present disclosure, the first sub-light mask includes the substrate, a semi-transparent layer located on the substrate and having a second pattern, and a light-shielding layer located on a side of the semi-transparent layer with the second pattern away from the substrate and having a third pattern; the second sub-light mask includes the substrate, a semi-transparent layer located on the substrate and having the second pattern, and a light-shielding layer located on a side of the semi-transparent layer with the second pattern away from the substrate and having a first pattern; wherein,

[0043] The first pattern includes at least one first opening, the second pattern includes at least one second opening exposing the substrate, and the third pattern includes a third opening;

[0044] In the first sub-mask, the orthographic projection of the third opening on the substrate covers the orthographic projection of the second opening on the substrate;

[0045] In the second sub-mask, an orthographic projection of the second opening on the substrate overlaps with an orthographic projection of the first opening on the substrate.

[0046] In the mask preparation method and mask provided by the present invention, by utilizing the same substrate and in the same patterning process, a first sub-mask and a second sub-mask with different structures are formed on different regions on the substrate, respectively, thereby reducing the difficulty of making a hybrid mask and saving production costs.

[0047] Other aspects will be apparent upon reading and understanding the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and are used together with the description to explain the principles of the embodiments of the present disclosure. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present disclosure, rather than all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 The figure is a flow chart of a method for preparing a photomask according to an exemplary embodiment.

[0050] Figure 2 is a plan view of a substrate according to an exemplary embodiment.

[0051] Figure 3 The figure is a flow chart of a method for preparing a photomask according to an exemplary embodiment.

[0052] Figure 4 The figure is a flow chart of a method for preparing a photomask according to an exemplary embodiment.

[0053] Figure 5 The figure is a flow chart of a method for preparing a photomask according to an exemplary embodiment.

[0054] Figure 6 The figure is a schematic diagram of a first identifier and a second identifier according to an exemplary embodiment.

[0055] Figure 7 FIG. 4 is a schematic structural diagram of a photomask according to an exemplary embodiment.

[0056] Figure 8 The figure is a flow chart of a method for preparing a photomask according to an exemplary embodiment.

[0057] Fig. 9The figure is a flow chart of a method for preparing a photomask according to an exemplary embodiment.

[0058] Fig.10 is a schematic plan view of a photomask according to an exemplary embodiment.

[0059] Fig.11 is a schematic plan view of a photomask according to an exemplary embodiment.

[0060] Description of reference numerals:

[0061] Substrate-10; first area A1; second area B1; base-11; semi-transparent layer-12; light shielding layer-13; first sub-mask-20; second sub-mask-30; photoresist-40; first mark-51; second mark-52; first opening-61; second opening-62; third opening-63. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other without conflict.

[0063] The photolithography process is one of the main processes in semiconductor manufacturing. The photolithography process is used to form a predefined pattern on a photoresist to manufacture various devices. The photolithography process generally includes three basic steps: coating, exposure and development, wherein, in the coating step, the photoresist is coated to cover the entire upper surface of the wafer. In the exposure step, the photoresist is exposed to light through a predetermined photomask. In the development step, the photoresist is developed to remove the exposed portion or the unexposed portion to form a pattern transferred in the photoresist. In this photolithography process, the pattern transfer from the photomask to the photoresist requires position matching from the photomask to the photoresist, otherwise, the wafer may be unusable or even discarded. Therefore, in the process of photolithography, the photomask becomes one of the indispensable and important molds, affecting the resolution of the transfer pattern on the wafer.

[0064] A common method for improving the resolution of the pattern formed on the wafer is to use a binary intensity mask (BIN) and a phase shift mask (PSM) to continuously expose the photoresist during the photolithography process to complete the double exposure operation of the photoresist. However, in the process of making the PSM mask and the BIN mask, not only do they need to be prepared separately on two different substrates, but there is also a waste of space on each substrate, thus making the process of making the mask complicated and costly.

[0065] In view of this, an embodiment of the present disclosure provides a method for preparing a mask, the method for preparing the mask comprising: providing a substrate, the substrate comprising a base, a semi-transparent layer and a light-shielding layer stacked in sequence, the substrate having a first area and a second area. In the same patterning process, a first sub-mask is formed in the first area, and a second sub-mask is formed in the second area, and the first sub-mask is different from the second sub-mask. In this way, based on the different film layer structures stacked on the substrate, in the same patterning process, a design scheme of a mask (i.e., a hybrid mask) having a first sub-mask and a second sub-mask with different mask patterns is formed on different areas of the substrate, which simplifies the production process of the hybrid mask, thereby saving production costs.

[0066] The present disclosure is described below in conjunction with the accompanying drawings and specific embodiments.

[0067] The exemplary embodiment of the present disclosure provides a method for preparing a photomask, such as Figure 1 and Figure 2 As shown, Figure 1 is a flow chart of a method for preparing a photomask according to an exemplary embodiment. Figure 2 is a plan view of a substrate according to an exemplary embodiment, the method comprising the following steps:

[0068] Step S100, providing a substrate 10, the substrate 10 comprising a base 11, a semi-transmissive layer 12 and a light shielding layer 13 stacked in sequence, the substrate 10 having a first area A1 and a second area B1;

[0069] Step S200 , in the same patterning process, forming a first sub-mask 20 in the first area A1 , and forming a second sub-mask 30 in the second area B1 , wherein the first sub-mask 20 is different from the second sub-mask 30 .

[0070] In step S100, the substrate 10 includes a stacked base 11, a semi-transparent layer 12 and a light shielding layer 13, wherein the base 11 is used to carry other film layers of the mask, the base 11 can be a transparent base, and the material of the base 11 includes quartz glass, borosilicate glass, soda-lime glass or resin; the semi-transparent layer 12 is a phase conversion material, which controls the thickness to allow light to be converted 180 degrees from the original phase, eliminating the interference effect of light in the interface transition zone, thereby increasing the resolution of the interface graphics. The material of the semi-transparent layer 12 includes a semi-transparent material (transmittance 6%, 18%, 20%...), such as at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN. The light shielding layer 13 is used to block light during photolithography, so that the image on the mask is transferred to the etching object such as a wafer, and the material of the light shielding layer 13 includes metal chromium or chromium oxide.

[0071] The substrate 10 is divided into a first area A1 for forming the first sub-mask 20, and a second area B1 for forming the second sub-mask 30. Exemplarily, the first sub-mask 20 may be a PSM mask, and the second sub-mask 30 may be a BIN mask. In this embodiment, the first sub-mask 20 and the second sub-mask 30 are made on the same substrate 10, which saves production costs compared to the related art in which the first sub-mask 20 and the second sub-mask 30 are made on two different substrates.

[0072] In step S200, the process of forming the first sub-mask 20 and the second sub-mask 30 in the first area A1 and the second area B1 of the substrate 11 is implemented under the same patterning process, that is, in the same patterning process, the first area A1 and the second area B1 are patterned at the same time to obtain the first sub-mask 20 and the second sub-mask 30 with different mask patterns. With such a design, the number of patterning processes is reduced in the process of the first sub-mask 20 and the second sub-mask 30, thereby simplifying the manufacturing process of the first sub-mask 20 and the second sub-mask 30, and further saving production costs.

[0073] It should be understood that the patterning process may include exposure, development and etching, and the same patterning process means that the process steps performed at the same time are the same. A plurality of first areas A1 and a plurality of second areas B1 can be divided on the substrate 10, and the first area A1 and the second area B1 are arranged at intervals and do not touch each other. Similarly, the first area A1 and the first area A1 are also arranged at intervals and do not touch each other, and the second area B1 and the second area B1 are also arranged at intervals and do not touch each other. In other words, the first area A1 and the second area B1 can be any two areas on the substrate 10 that do not overlap, and can also be understood as the orthographic projections of the first area A1 and the second area B1 on the substrate 10 that do not overlap. There are many ways to arrange the first area A1 and the second area B1 on the substrate 10, for example, the first area A1 and the second area B1 are arranged adjacent to each other; for example, the first area A1 and the second area B1 are arranged at intervals from each other or the first area A1 and the second area B1 are arranged alternately.

[0074] The number of the first regions A1 and the second regions B1 may be the same or different. For example, there may be a plurality of first regions A1 and one second region B1. Figure 2 It is merely illustrative that two first areas A1 and two second areas B1 are provided on the substrate 10 , but the present invention is not limited thereto.

[0075] In step S200, in the same patterning process, a first sub-mask 20 is formed in the first area A1, and a second sub-mask 30 is formed in the second area B1, wherein the same patterning process includes a first patterning process and a second patterning process; as an example, Figure 3 As shown, step S200 includes:

[0076] Step S210: Performing a first patterning process on the light shielding layer 13 and the semi-transparent layer 12 located in the first area A1 and the second area B1, thereby forming a first pattern in the light shielding layer 13 located in the first area A1 and the second area B1, and forming a second pattern in the semi-transparent layer 12 located in the first area A1 and the second area B1;

[0077] Step S220, through a second patterning process, the first graphic located in the first area A1 is subjected to a second patterning process to form a third graphic, and the second graphic located in the first area A1, the first graphic located in the second area B1 and the second graphic located in the second area B1 are not subjected to patterning process.

[0078] In step S210, the first area A1 and the second area B1 of the substrate 10 are patterned by exposure, development, and photolithography processes to form a first pattern in the light shielding layer 13 of the first area A1 and the light shielding layer 13 of the second area B1, and a second pattern in the semi-transparent layer 12 of the first area A1 and the semi-transparent layer 12 of the second area B1. It should be understood that the first pattern and the second pattern may be the same or different. In this embodiment, the first pattern and the second pattern are the same. In addition, the patterning process for forming the first pattern and the second pattern may include one or multiple photolithography processes, which may be selected according to the thickness of the semi-transparent layer 12 and the light shielding layer 13 and the corresponding pattern.

[0079] In step S220, the first area A1 and the second area B1 of the substrate 10 are subjected to secondary patterning by exposure, development, and photolithography processes. Specifically, the light shielding layer 13 used to form the first pattern in the first area A1 is patterned to form a third pattern. That is, the first pattern in the light shielding layer 13 is patterned to form a third pattern, and the third pattern replaces the original first pattern, while the second pattern on the semi-transparent layer 12 of the first area A1 remains unchanged. At the same time, the first pattern in the light shielding layer 13 of the second area B1 and the second pattern in the semi-transparent layer 12 of the second area B1 remain unchanged, that is, in step S220, only the light shielding layer 13 in the first area is patterned, while the light shielding layer 13 in the second area B1 is not patterned.

[0080] In step S220, the first pattern in the light shielding layer 13 of the first area A1 is patterned to form a third pattern, and the first pattern in the light shielding layer 13 of the second area B1 remains unchanged. Figure 4 As shown, through the second patterning process, the first graphic located in the first area A1 is subjected to a second patterning process to form a third graphic, and the second graphic located in the first area A1, the first graphic located in the second area B1, and the second graphic located in the second area B1 are not subjected to patterning process, including:

[0081] Step S221, coating a photoresist 40 on the surface of the first patterned light shielding layer 13 and the substrate 11 located in the first area A1 and the second area B1, wherein the surface of the substrate 11 is the portion exposed by the first pattern and the second pattern;

[0082] Step S222, defining a third pattern on the photoresist 40 located in the first area A1, and not defining a pattern on the photoresist 40 located in the second area B1;

[0083] Step S223, using the photoresist 40 having the third pattern as a mask, etching the first patterned light shielding layer 13 located in the first area A1, and forming a third pattern in the light shielding layer 13 located in the first area A1;

[0084] Step S224 , removing the photoresist 40 .

[0085] In step S221, in some embodiments, the photoresist 40 covers the surface of the substrate 10, that is, covers the surface of the light-shielding layer 13 facing away from the base 11 and the surface of the substrate 11 exposed by the first pattern and the second pattern, that is, the photoresist 40 covers the surface of the substrate 10 and fills the area on the substrate 10 exposed in the first pattern and the second pattern.

[0086] In step S222, the photoresist 40 in the first area A1 is patterned, that is, the photoresist 40 used to form the first pattern in the first area A1 is patterned, and the third pattern is formed in the area where the first pattern was originally formed. When the photoresist 40 in the first area A1 is patterned, the photoresist 40 in the second area B1 is not patterned, so as to protect the first pattern already formed in the light shielding layer 13 of the second area B1 and the second pattern already formed in the semi-transparent layer 12 of the second area B1.

[0087] In step S223, based on the third pattern defined on the photoresist 40, the partial light shielding layer 13 located in the first area A1 is patterned to obtain a third pattern. The partial light shielding layer 13 in the first area A1 refers to the partial light shielding layer 13 in the first area A1 where the first pattern has been formed. The patterning process is performed on the first area A1 and the second area B1 at the same time. Due to the protective effect of the photoresist 40 located in the second area B1 on the light shielding layer 13 in the second area B1, the first pattern already formed by the light shielding layer 13 in the second area B1 and the second pattern already formed by the semi-transparent layer 12 in the second area B1 are prevented from being affected by this patterning process.

[0088] In step S224, the photoresist 40 on the substrate 10 is removed, that is, the photoresist 40 covering the first area A1 and the second area B1 is removed, and the first sub-mask 20 and the second sub-mask 30 having different patterns are obtained. The first sub-mask 20 located in the first area A1 includes a substrate 11, a semi-transmissive layer 12 having a second pattern located on the substrate 11, and a light shielding layer 13 having a third pattern located on the side of the semi-transmissive layer 12 away from the substrate 11. The second sub-mask 30 located in the second area B1 includes a substrate 11, a semi-transmissive layer 12 having a second pattern located on the substrate 11, and a light shielding layer 13 having a first pattern located on the side of the semi-transmissive layer 12 away from the substrate 11.

[0089] In some embodiments, Figure 5 As shown, a third pattern is defined on the photoresist 40 located in the first area A1, and no pattern is defined on the photoresist 40 located in the second area B1, including:

[0090] Step S2221, forming a first mark 51 in the first area A1, and forming a second mark 52 in the second area B1;

[0091] Step S2222, the photolithography equipment identifies the first mark 51 and the second mark 52, patterns the photoresist 40 located in the first area A1 corresponding to the first mark 51, forms a third graphic in the photoresist 40 located in the first area A1, and does not pattern the photoresist 40 located in the second area B1 corresponding to the second mark 52.

[0092] In step S2221, a plane geometric figure is made in the first area A1 for forming the first sub-mask 20 as the first mark 51, and another plane geometric figure is made in the second area B1 for forming the second sub-mask 30 as the second mark 52. The plane geometric figure corresponding to the first mark 51 is different from the plane geometric figure corresponding to the second mark 52. The light in the patterning process penetrates or is blocked at specific positions of the first mark 51 and the second mark 52, respectively, so that the lithography equipment can identify the first mark 51 and the second mark 52, so that the lithography equipment selectively patterns the first area A1 and the second area B1.

[0093] In step S2222, the lithography device identifies the first mark 51 and the second mark 52 during the patterning process. As an example, the light emitted by the lithography device is partially blocked by the first mark 51 in the first area A1, and the remaining part patterns the photoresist 40 in the first area A1 to form a third figure; the light emitted by the lithography device is completely blocked by the second mark 52 in the second area B1, and is not irradiated onto the photoresist 40 in the second area B1. Therefore, the photoresist 40 in the second area B1 is not patterned.

[0094] In some possible implementations, the first mark 51 is a ring-shaped figure located in the first area A1 and arranged around the edge of the first area A1. The second mark 52 is a closed figure that fully covers the second area B1.

[0095] like Figure 6As shown, as an example, the orthographic projection of the first mark 51 on the substrate 11 falls within the first area A1, and the plane geometric figure of the first mark 51 is a ring figure, and the trajectory of the outer circle of the ring figure coincides with the edge of the first area A1, wherein the edge of the first area A1 refers to the line or geometric shape that delimits the first area A1 on the substrate 10. The area delimited between the ring line of the outer circle and the ring line of the inner circle of the ring figure is the light-blocked area, and the photoresist 40 in the area is not processed during the photolithography process, and the area other than the area blocked by the ring figure, i.e., the area delimited by the inner circle, is the light-penetrating area, and the photoresist 40 in the area is processed during the patterning process.

[0096] The planar geometric figure of the second mark 52 is a closed figure that completely covers the second area B1, that is, the orthographic projection of the second mark 52 on the substrate 11 covers the orthographic projection of the photoresist 40 located in the second area B1 on the substrate 11, so that during the patterning process, the second area B1 covered by the second mark 52 is a light-blocked area, that is, all the photoresists 40 in the second area B1 are not processed during the photolithography process.

[0097] In some possible implementations, the shapes of the first area A1 and the second area B1 are both rectangular, the first mark 51 is a rectangular ring shape, and the second mark 52 is a rectangular shape.

[0098] like Figure 6 As shown, as an example, the plane shape of the first area A1 is a rectangle, that is, the line that delimits the edge of the first area A1 is a rectangular frame line, and the corresponding first mark 51 disposed in the first area A1 and surrounding the rectangular edge of the first area A1 is a rectangular ring shape. The plane shape of the second area B1 is also a rectangle, and the corresponding second mark 52 that fully covers the second area B1 is a rectangular shape.

[0099] It should be understood that the plane shapes of the first area A1 and the second area B1 are not limited to the rectangles used as examples above, and can also be set to other shapes. For example, the plane shapes of the first area A1 and the second area B1 are circular or hexagonal, and the corresponding plane geometric figure of the first mark 51 is a circular ring figure or a hexagonal ring figure, and the plane geometric figure of the second mark 52 is a circular figure or a hexagonal figure. In addition, the plane shapes of the first area A1 and the second area B1 can be the same or different, which can be designed according to actual production needs.

[0100] In some possible implementations, such as Figure 7 As shown, Figure 7is a schematic diagram of the structure of a photomask according to an exemplary embodiment. The first pattern formed in different film layers of the substrate 10 includes at least one first opening 61 formed in the light shielding layer 13, the second pattern includes at least one second opening 62 formed in the semi-transparent layer 12 and exposing the substrate 11, and the third pattern includes a third opening 63 formed in the light shielding layer 13. In the first area A1, the orthographic projection of the third opening 63 on the substrate 11 covers the orthographic projection of the second opening 62 on the substrate 11, and the orthographic projection of the second opening 62 on the substrate overlaps with the orthographic projection of the first opening 61 on the substrate 11. In the second area B1, the orthographic projection of the second opening 62 on the substrate 11 overlaps with the orthographic projection of the first opening 61 on the substrate 11.

[0101] In some possible implementations, continue to refer to Figure 7 It can be seen that the plane geometric shapes of the first figure and the second figure formed in the method for preparing the photomask illustrated in the above embodiment are the same; and / or, the orthographic projection of the first area A1 on the substrate 11 falls outside the orthographic projection of the second area B1 on the substrate 11. In other words, the first area A1 and the second area B1 are spaced apart on the substrate 11, and there is no overlapping or overlapping area between the two.

[0102] There are many photolithography schemes for forming the first pattern on the light shielding layer 13 and the second pattern on the semi-transmissive layer 12, which are described below by way of examples.

[0103] As an example, Figure 8 As shown, through a first patterning process, the light shielding layer 13 and the semi-transparent layer 12 located in the first area A1 and the second area B1 are subjected to a first patterning process, a first pattern is formed in the light shielding layer 13 located in the first area A1 and the second area B1, and a second pattern is formed in the semi-transparent layer 12 located in the first area A1 and the second area B1, including:

[0104] Step S211, coating a photoresist 40 on the surface of the light shielding layer 13 located in the first area A1 and the second area B1;

[0105] Step S212, patterning the photoresist 40, forming a photolithography pattern in the photoresist 40;

[0106] Step S213, using the photoresist 40 with the photolithography pattern as a mask, etching the light shielding layer 13 and the semi-transparent layer 12, forming a first pattern in the light shielding layer 13 located in the first area A1 and the second area B1, and forming a second pattern in the semi-transparent layer 12 located in the first area A1 and the second area B1;

[0107] Step S214 , removing the photoresist 40 .

[0108] As another example, Fig. 9As shown, through a first patterning process, the light shielding layer 13 and the semi-transparent layer 12 located in the first area A1 and the second area B1 are subjected to a first patterning process, a first pattern is formed in the light shielding layer 13 located in the first area A1 and the second area B1, and a second pattern is formed in the semi-transparent layer 12 located in the first area A1 and the second area B1, including:

[0109] Step S211, coating a photoresist 40 on the surface of the light shielding layer 13 located in the first area A1 and the second area B1;

[0110] Step S212, patterning the photoresist 40, forming a photolithography pattern in the photoresist 40;

[0111] Step S213, using the photoresist 40 with the photolithography pattern as a mask, etching the light shielding layer 13 to form a first pattern in the light shielding layer 13 located in the first area A1 and the second area B1;

[0112] Step S214, using the light shielding layer 13 having the first pattern as a mask, etching the semi-transparent layer 12 to form a second pattern in the semi-transparent layer 12 located in the first area A1 and the second area B1;

[0113] Step S215 , removing the photoresist 40 .

[0114] In the above embodiments or examples, the material of the light shielding layer 13 includes metal chromium or chromium oxide, and / or the material of the semi-transmissive layer 12 includes at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN.

[0115] In some possible implementations, such as Figure 7 As shown, the first sub-light mask 20 includes a substrate 11, a semi-transmissive layer 12 located on the substrate 11 and having a second pattern, and a light shielding layer 13 located on the side of the semi-transmissive layer 12 with the second pattern away from the substrate 11 and having a third pattern. The second sub-light mask 30 includes a substrate 11, a semi-transmissive layer 12 located on the substrate 11 and having a second pattern, and a light shielding layer 13 located on the side of the semi-transmissive layer 12 with the second pattern away from the substrate 11 and having a first pattern.

[0116] As an example, the first pattern includes a plurality of first openings 61 formed in the light shielding layer 13, the second pattern includes a plurality of second openings 62 formed in the semi-transparent layer 12 and exposing the substrate 11, and the third pattern includes a third opening 63 formed in the light shielding layer 13, and the third opening 63 is formed in the region of the light shielding layer 13 for forming the first opening 61. In the first region A1, the orthographic projection of the third opening 63 on the substrate 11 covers the orthographic projection of the second opening 62 on the substrate 11. In the second region B1, the orthographic projection of the second opening 62 on the substrate 11 overlaps with the orthographic projection of the first opening 61 on the substrate 11. In this way, the light shielding layer 13 in the first region A1 has the third opening 63, the semi-transparent layer 12 in the first region A1 has the second opening 62, and the first sub-mask 20 formed in the first region A1 is a PSM mask; the light shielding layer 13 in the second region B1 has the first opening 61, the semi-transparent layer 12 in the second region B1 has the second opening 62, and the second sub-mask 30 formed in the second region B1 is a BIN mask.

[0117] The present disclosure exemplarily provides a photomask, referring to Figure 2 and Figure 7 As shown, the photomask includes a substrate 10, which includes a base 11, a semi-transparent layer 12 and a light shielding layer 13 stacked in sequence, wherein the base 11 can be a transparent base, and the material of the base includes quartz glass, borosilicate glass, soda-lime glass or resin; the semi-transparent layer 12 is a phase conversion material, which controls the thickness to allow light to be converted 180 degrees from the original phase, eliminates the interference effect of light in the interface transition zone, and thus increases the resolution of the interface graphics. The material of the semi-transparent layer 12 includes a semi-transparent material (transmittance 6%, 18%, 20%...), such as at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN. The light shielding layer 13 is used to block light during photolithography, so that the image on the photomask is transferred to the etching object such as a wafer, and the material of the light shielding layer 13 includes metal chromium or chromium oxide.

[0118] The first area A1 and the second area B1 of the substrate 10 do not overlap. A first sub-mask 20 is disposed in the first area A1, and a second sub-mask 30 is disposed in the second area B1, and the first sub-mask 20 is different from the second sub-mask 30. Exemplarily, the first mask 20 may be a PSM mask, and the second mask 30 may be a BIN mask, and both are prepared on the same substrate 10, which not only makes full use of the space of the substrate 10, but also does not need to provide an additional substrate (a substrate stacked with other film layers), thereby saving production costs.

[0119] In some possible embodiments, the substrate 10 is distributed with a plurality of repeating units, each of which is provided with at least one first region A1 and at least one second region B1, wherein the first region A1 is used to form the first mask 20, and the second region B1 is used to form the second mask 30. As an example, each repeating unit includes two first sub-masks 20 and two second sub-masks 30. There are many ways to arrange the two first sub-masks 20 and the two second sub-masks 30 in one repeating unit, for example, the two first sub-masks 20 are located in the first row, and the two second sub-masks 30 are located in the second row. For another example, referring to Figure 6 , two first sub-light masks 20 are located in the first column, and two second sub-light masks 30 are located in the second column.

[0120] As an example, Fig.10 As shown, the number of the first area A1 and the second area B1 on the substrate 10 are both two, and the first area A1 and the second area B1 are arranged in an array in the substrate 10. The substrate 10 includes two corresponding first sub-masks 20 and second sub-masks 30, and the first sub-masks 20 and the second sub-masks 30 are arranged in two rows and two columns.

[0121] It should be understood that the above is only an exemplary display of the distribution of the first sub-light mask 20 and the second sub-light mask 30, and does not limit the number of the first sub-light mask 20 and the second sub-light mask 30 and the size of the plane area between the two. In addition, the distribution of the first sub-light mask 20 and the second sub-light mask 30 is not limited to the above solution, and it can also be arranged in other ways, for example, Fig.11 As shown, a plurality of repeating units arranged in an array are provided on the substrate 10, each repeating unit includes two first sub-masks 20 and two second sub-masks 30, adjacent first sub-masks 20 and second sub-masks 30 are provided on the same row, and adjacent first sub-masks 20 and second sub-masks 30 are provided on the same column. All of the above can be adjusted according to production requirements, and will not be described in detail here.

[0122] In some embodiments, Figure 7As shown, the first sub-light mask 20 includes a substrate 11, a semi-transparent layer 12 located on the substrate 11 and having a second pattern, and a light-shielding layer 13 located on the side of the semi-transparent layer 12 with the second pattern away from the substrate 11 and having a third pattern; the second sub-light mask 30 includes the substrate 11, the semi-transparent layer 12 located on the substrate 11 and having a second pattern, and the light-shielding layer 13 located on the side of the semi-transparent layer 12 with the second pattern away from the substrate 11 and having a first pattern; wherein the first pattern includes at least one first opening 61, the second pattern includes at least one second opening 62 exposing the substrate 12, and the third pattern includes a third opening 63; in the first sub-light mask 20, the orthographic projection of the third opening 63 on the substrate 11 covers the orthographic projection of the second opening 62 on the substrate 11; in the second sub-light mask 30, the orthographic projection of the second opening 62 on the substrate 11 overlaps with the orthographic projection of the first opening 61 on the substrate 11.

[0123] That is, the substrate 10 forming the mask includes a base 11, a semi-transparent layer 12 and a light shielding layer 13 which are stacked in sequence, and the substrate 10 is divided into a first area A1 and a second area B1, wherein a first sub-mask 20 is formed in the first area A1, and a second sub-mask 30 is formed in the second area B1, and the first sub-mask 20 includes a third opening 63 formed in the light shielding layer 13 located in the first area A1 and a second opening 62 formed in the semi-transparent layer 12 located in the first area A1; the second sub-mask 30 includes a first opening 61 formed in the light shielding layer 13 located in the second area B1 and a second opening 62 formed in the semi-transparent layer 12 located in the second area B1. In the disclosed embodiment, by using the same substrate 10 and in the same patterning process, the first sub-mask 20 and the second sub-mask 30 with different structures are formed on different areas on the substrate 10, respectively, thereby reducing the difficulty of making the hybrid mask and saving production costs.

[0124] In the present disclosure, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such article or device. In the absence of more restrictions, the elements defined by the sentence "comprising..." do not exclude the presence of other identical elements in the article or device comprising the elements.

[0125] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0126] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the intent of the present disclosure also includes these modifications and variations.

Claims

1. A method for preparing a photomask, characterized in that: include: Providing a substrate, the substrate comprising a base, a semi-transmissive layer and a light shielding layer stacked in sequence, the substrate having a first area and a second area; In the same patterning process, a first sub-mask is formed in the first region, and a second sub-mask is formed in the second region, wherein the first sub-mask is different from the second sub-mask.

2. The method for preparing a photomask according to claim 1, characterized in that: In the same patterning process, forming a first sub-mask in the first region and forming a second sub-mask in the second region comprises: The same patterning process includes a first patterning process and a second patterning process, through which the light shielding layer and the semi-transparent layer located in the first area and the second area are subjected to a first patterning process, a first pattern is formed in the light shielding layer located in the first area and the second area, and a second pattern is formed in the semi-transparent layer located in the first area and the second area; Through the second patterning process, the first graphic located in the first area is subjected to a second patterning process to form a third graphic, and the second graphic located in the first area, the first graphic located in the second area, and the second graphic located in the second area are not subjected to patterning process.

3. The method for preparing a photomask according to claim 2, characterized in that: The second patterning process is used to perform a second patterning process on the first graphic located in the first area to form a third graphic, and the second graphic located in the first area, the first graphic located in the second area, and the second graphic located in the second area are not patterned, including: Coating a photoresist on the first patterned light shielding layer located in the first area and the second area and on the surface of the substrate, wherein the surface of the substrate is a portion exposed by the first pattern and the second pattern; The third pattern is defined on the photoresist located in the first area, and no pattern is defined on the photoresist located in the second area; Using the photoresist having the third pattern as a mask, etching the first patterned light shielding layer located in the first area to form the third pattern in the light shielding layer located in the first area; The photoresist is removed.

4. The method for preparing a photomask according to claim 3, characterized in that: The method further comprises: defining the third pattern on the photoresist located in the first area, and not defining a pattern on the photoresist located in the second area. forming a first mark in the first area and forming a second mark in the second area; The photolithography equipment identifies the first mark and the second mark, patterns the photoresist located in the first area corresponding to the first mark, forms a third pattern in the photoresist located in the first area, and does not pattern the photoresist located in the second area corresponding to the second mark.

5. The method for preparing a photomask according to claim 4, characterized in that: The first mark is a ring-shaped figure located in the first area and arranged around the edge of the first area; the second mark is a closed figure that completely covers the second area.

6. The method for preparing a photomask according to claim 5, characterized in that: The shapes of the first area and the second area are both rectangular; the first mark is a rectangular ring figure, and the second mark is a rectangular figure.

7. The method for preparing a photomask according to any one of claims 2 to 6, characterized in that: The first pattern includes at least one first opening, the second pattern includes at least one second opening exposing the substrate, and the third pattern includes a third opening; In the first region, the orthographic projection of the third opening on the substrate covers the orthographic projection of the second opening on the substrate, and the orthographic projection of the second opening on the substrate overlaps with the orthographic projection of the first opening on the substrate; In the second region, an orthographic projection of the second opening on the substrate overlaps with an orthographic projection of the first opening on the substrate.

8. The method for preparing a photomask according to any one of claims 2 to 6, characterized in that: The first graphic and the second graphic are the same; and / or The orthographic projection of the first region on the substrate falls outside the orthographic projection of the second region on the substrate.

9. The method for preparing a photomask according to any one of claims 2 to 6, characterized in that: The method comprises: performing a first patterning process on the light shielding layer and the semi-transparent layer located in the first area and the second area, forming a first pattern in the light shielding layer located in the first area and the second area, and forming a second pattern in the semi-transparent layer located in the first area and the second area, including: Coating a photoresist on the surface of the light shielding layer located in the first area and the second area; patterning the photoresist to form a photolithographic pattern in the photoresist; Using the photoresist having the photolithography pattern as a mask, etching the light shielding layer and the semi-transparent layer, forming the first pattern in the light shielding layer located in the first area and the second area, and forming the second pattern in the semi-transparent layer located in the first area and the second area; The photoresist is removed.

10. The method for preparing a photomask according to any one of claims 2 to 6, characterized in that: The method comprises: performing a first patterning process on the light shielding layer and the semi-transparent layer located in the first area and the second area, forming a first pattern in the light shielding layer located in the first area and the second area, and forming a second pattern in the semi-transparent layer located in the first area and the second area, including: Coating a photoresist on the surface of the light shielding layer located in the first area and the second area; patterning the photoresist to form a photolithographic pattern in the photoresist; Using the photoresist having the photolithography pattern as a mask, etching the light shielding layer to form the first pattern in the light shielding layer located in the first area and the second area; Using the light shielding layer having the first pattern as a mask, etching the semi-transparent layer to form a second pattern in the semi-transparent layer located in the first area and the second area; The photoresist is removed.

11. The method for preparing a photomask according to any one of claims 1 to 6, characterized in that: The material of the light shielding layer includes metallic chromium or chromium oxide; and / or The material of the semi-transmissive layer includes at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN.

12. The method for preparing a photomask according to any one of claims 2 to 6, characterized in that: The first sub-mask includes the substrate, a semi-transmissive layer located on the substrate and having the second pattern, and a light shielding layer located on a side of the semi-transmissive layer having the second pattern away from the substrate and having the third pattern; The second sub-mask includes the substrate, a semi-transmissive layer located on the substrate and having the second pattern, and a light shielding layer located on a side of the semi-transmissive layer having the second pattern away from the substrate and having the first pattern.

13. A photomask, characterized in that: The mask comprises a substrate, the substrate comprises a base, a semi-transmissive layer and a light shielding layer stacked in sequence, and the substrate has a first area and a second area; A first sub-light mask is disposed in the first area, a second sub-light mask is disposed in the second area, and the first sub-light mask is different from the second sub-light mask.

14. The photomask according to claim 13, wherein: The material of the light shielding layer includes metallic chromium or chromium oxide; and / or The material of the semi-transmissive layer includes at least one of MoSiON, molybdenum silicon, ZrSiN and TiSiN.

15. The light mask according to claim 13 or 14, characterized in that: The first sub-light mask comprises the substrate, a semi-transparent layer located on the substrate and having a second pattern, and a light-shielding layer located on a side of the semi-transparent layer with the second pattern away from the substrate and having a third pattern; the second sub-light mask comprises the substrate, a semi-transparent layer located on the substrate and having the second pattern, and a light-shielding layer located on a side of the semi-transparent layer with the second pattern away from the substrate and having a first pattern; wherein, The first pattern includes at least one first opening, the second pattern includes at least one second opening exposing the substrate, and the third pattern includes a third opening; In the first sub-mask, the orthographic projection of the third opening on the substrate covers the orthographic projection of the second opening on the substrate; In the second sub-mask, an orthographic projection of the second opening on the substrate overlaps with an orthographic projection of the first opening on the substrate.

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