Self-aligned multi-patterning preparation method
By preparing photoresist layers with different photosensitive properties on the substrate and exposing and developing, combining coating and peeling processes, the problem of inefficient production efficiency caused by complex processes in the prior art is solved, and multiple patterned self-alignment is achieved and efficient production.
Patent Information
- Application Number
- CN202411410779.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-10
- Publication Date
- 2024-12-27
AI Technical Summary
The existing self-aligned multiple patterning process is complex, resulting in low productivity and efficiency, making it difficult to effectively form multiple patterning patterns.
By preparing first and second photoresist layers with different photosensitive properties on the substrate, and exposing and developing them at the same location, multiple patterned patterns can be formed using the difference in photosensitive properties, and then coating and peeling processes can be used to form them. Multi-patterned mask.
The process steps are simplified, the yield and efficiency of production are improved, and the self-alignment of multiple patterns is realized, avoiding complex multiple coating and etching processes.
Smart Images
Figure CN119200345A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present invention relate to the field of nano-processing technology, and in particular to a preparation method of self-aligned multiple patterning. Background Art
[0002] Multiple patterning is a common method used in photolithography to reduce process feature size and increase product surface performance, including self-aligned double patterning and self-aligned quadruple patterning. However, in the prior art, due to the different film materials, the required etching formula and process are relatively complex, and a complex process is required to form a self-aligned multiple patterning graphic, resulting in reduced production yield and production efficiency. Summary of the invention
[0003] The present invention provides a method for preparing self-aligned multiple patterns. By exposing a first photoresist layer and a second photoresist layer with different photosensitivity at the same position and treating them under the same development conditions, self-alignment of multiple patterns can be achieved. The process and steps are simple and convenient, and production yield and production efficiency can be improved.
[0004] In a first aspect, the present invention provides a method for preparing self-aligned multiple patterning, comprising:
[0005] providing a substrate;
[0006] Preparing a first photoresist layer and a second photoresist layer on one side of the substrate, respectively, wherein the photosensitivity of the first photoresist layer is different from the photosensitivity of the second photoresist layer;
[0007] The first photoresist layer and the second photoresist layer are exposed and developed to complete self-alignment of multiple patterns on the first photoresist layer and the second photoresist layer.
[0008] Optionally, the first photoresist layer is located on a side of the second photoresist layer close to the substrate, and the photosensitivity of the first photoresist layer is greater than that of the second photoresist layer;
[0009] The exposing and developing the first photoresist layer and the second photoresist layer comprises:
[0010] The first photoresist layer and the second photoresist layer are simultaneously exposed by an exposure process, and developed by a developer to form a multi-patterned pattern on the first photoresist layer and the second photoresist layer, and the vertical projection of the pattern formed on the second photoresist layer on the substrate covers the vertical projection of the pattern formed on the first photoresist layer on the substrate.
[0011] Optionally, after the first photoresist layer and the second photoresist layer are exposed and developed, the method further includes:
[0012] The coating is performed by magnetron sputtering or electron beam evaporation to form a first coating structure directly above the pattern formed by the second photoresist layer and a second coating structure at intervals between the patterns formed by the first photoresist layer.
[0013] Optionally, after coating by magnetron sputtering or electron beam evaporation, the method further comprises:
[0014] The pattern formed by the second photoresist layer and the first coating structure are removed by a stripping process, and the pattern formed by the first photoresist layer and the second coating structure are retained to form a double pattern mask.
[0015] Optionally, before respectively preparing the first photoresist layer and the second photoresist layer on one side of the substrate, the method further includes:
[0016] Preparing an anti-reflective coating and an etching resistant layer on one side of the substrate;
[0017] After removing the pattern formed by the second photoresist layer and the first coating structure by the stripping process and retaining the pattern formed by the first photoresist layer and the second coating structure, the method further includes:
[0018] The mask pattern of the double pattern mask is transferred to the anti-reflective coating layer and the etching resistant layer.
[0019] Optionally, the first photoresist layer is located on a side of the second photoresist layer close to the substrate, and the photosensitivity of the first photoresist layer is lower than that of the second photoresist layer;
[0020] The exposing and developing the first photoresist layer and the second photoresist layer comprises:
[0021] The first photoresist layer and the second photoresist layer are simultaneously exposed by an exposure process, and developed by a developer to form multiple patterned graphics on the first photoresist layer and the second photoresist layer, and the vertical projection of the pattern formed on the first photoresist layer on the substrate covers the vertical projection of the pattern formed on the second photoresist layer on the substrate.
[0022] Optionally, after the first photoresist layer and the second photoresist layer are exposed and developed, the method further includes:
[0023] Atomic layer deposition is used for coating to form a third coating structure on the top of the double pattern formed by the first photoresist layer and the second photoresist layer, a fourth coating structure is formed on the sidewall of the double pattern, and a fifth coating structure is formed at the interval position of the pattern formed by the first photoresist layer, wherein the top and the sidewall are interconnected to form the outer surface of the double pattern.
[0024] Optionally, the coating is performed by atomic layer deposition, further comprising:
[0025] The third coating structure and the fifth coating structure are etched by an etching process.
[0026] Optionally, after etching the third coating structure and the fifth coating structure using an etching process, the method further includes:
[0027] The fourth coating structure is used as a mask to etch downward the double pattern to form a quadruple pattern mask.
[0028] Optionally, before respectively preparing the first photoresist layer and the second photoresist layer on one side of the substrate, the method further includes:
[0029] Prepare an etching stop layer and an etching resistance layer on one side of the substrate;
[0030] After etching the double pattern using the fourth coating structure as a mask to form a quadruple pattern mask, the method further includes:
[0031] The mask pattern of the quadruple-pattern mask is transferred to the etch stop layer.
[0032] The embodiment of the present invention prepares a first photoresist layer and a second photoresist layer on one side of a substrate, wherein the photosensitivity of the first photoresist layer is different from the photosensitivity of the second photoresist layer, and performs exposure and development treatment on the first photoresist layer and the second photoresist layer, so as to complete self-alignment of multiple patterns on the first photoresist layer and the second photoresist layer. In this way, after the same exposure process and the same development conditions are processed, due to the difference in photosensitivity between the first photoresist layer and the second photoresist layer, patterns of different shapes can be formed on the first photoresist layer and the second photoresist layer. In addition, since the exposure positions of the first photoresist layer and the second photoresist layer are the same, the position of the pattern formed on the first photoresist layer is the same as the position formed on the second photoresist layer, so that self-alignment of multiple patterns is achieved, and the process and steps are simple and convenient, which can improve production yield and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 It is a schematic flow chart of a method for preparing self-aligned multiple patterning provided in the first embodiment of the present invention;
[0034] Figure 2 It is a schematic flow chart of another self-aligned multiple patterning preparation method provided in the second embodiment of the present invention;
[0035] Figure 3 This is a self-aligned multiple patterning preparation process diagram provided by the second embodiment of the present invention;
[0036] Figure 4 It is a schematic flow chart of another method for preparing self-aligned multiple patterning provided in the third embodiment of the present invention;
[0037] Figure 5 This is another self-aligned multiple patterning preparation process diagram provided in Example 3 of the present invention. DETAILED DESCRIPTION
[0038] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0039] Embodiment 1
[0040] Figure 1 FIG. 1 is a flow chart of a method for preparing self-aligned multiple patterning provided in Embodiment 1 of the present invention. Figure 1 As shown, the preparation method comprises:
[0041] S110 , providing a substrate.
[0042] In an embodiment of the present invention, the substrate may be a silicon substrate, a glass substrate or a metal substrate, or a composite substrate including a multilayer structure, which is not limited in the embodiment of the present invention. After providing the substrate, the substrate may be pre-processed, for example, polishing, cleaning, preheating, etc., which is not limited in the embodiment of the present invention.
[0043] S120, preparing a first photoresist layer and a second photoresist layer on one side of the substrate respectively.
[0044] Specifically, in the embodiment of the present invention, a first photoresist layer can be coated on one side of the substrate by a spin coating process, and the first photoresist layer formed on the substrate can be uniformly coated. Then, a second photoresist layer can be coated on the first photoresist layer by the same coating process, and the second photoresist layer can be uniformly coated to make the thickness of the second photoresist layer located on the side of the first photoresist layer away from the substrate uniform. It should be noted that the photosensitivity of the first photoresist layer and the second photoresist layer are different, that is, the photosensitivity of the first photoresist layer is greater than the photosensitivity of the second photoresist layer, or the photosensitivity of the first photoresist layer is less than the photosensitivity of the second photoresist layer, and those skilled in the art can set it as needed.
[0045] S130 , exposing and developing the first photoresist layer and the second photoresist layer to complete self-alignment of multiple patterns on the first photoresist layer and the second photoresist layer.
[0046] Specifically, after the first photoresist layer and the second photoresist layer are prepared, the same position of the first photoresist layer and the second photoresist layer can be exposed by a single exposure process, and after exposure, the first photoresist layer and the second photoresist layer are developed using the same development conditions. Wherein, the same development conditions can be understood as the concentration of the developer used by the first photoresist layer and the second photoresist layer is the same, and the development time of the two is the same. However, since the photosensitivity of the first photoresist layer and the second photoresist layer is different, the pattern formed on the first photoresist layer is different from the pattern formed on the second photoresist layer. It should be noted that after the same exposure process and the same development conditions, the vertical projection area of the pattern formed on the photoresist layer with low photosensitivity on the substrate is larger. In addition, since the exposure process is to expose the same position of the first photoresist layer and the second photoresist layer, after development, the pattern formed on the first photoresist layer and the pattern formed on the second photoresist layer are at the same position. In other words, along the thickness direction of the substrate, the pattern formed on the first photoresist layer overlaps with the pattern formed on the second photoresist layer. In this way, by exposing the first photoresist layer and the second photoresist layer with different photosensitivity at the same position and treating them under the same development conditions, self-alignment of multiple patterns can be achieved. The process and steps are simple and convenient, and the production yield and production efficiency can be improved.
[0047] In summary, the embodiment of the present invention prepares a first photoresist layer and a second photoresist layer on one side of a substrate, wherein the photosensitivity of the first photoresist layer is different from the photosensitivity of the second photoresist layer, and performs exposure and development treatment on the first photoresist layer and the second photoresist layer, so as to complete the self-alignment of multiple patterns in the first photoresist layer and the second photoresist layer. In this way, after being processed under the same exposure process and the same development conditions, due to the difference in photosensitivity between the first photoresist layer and the second photoresist layer, patterns of different shapes can be formed in the first photoresist layer and the second photoresist layer. In addition, since the exposure positions of the first photoresist layer and the second photoresist layer are the same, the position of the pattern formed on the first photoresist layer is the same as the position formed on the second photoresist layer, so that the self-alignment of multiple patterns is achieved, and the process and steps are simple and convenient, which can improve the production yield and production efficiency.
[0048] Embodiment 2
[0049] Figure 2 is a schematic flow chart of another self-aligned multiple patterning preparation method provided in the second embodiment of the present invention, Figure 3 This is a self-aligned multiple patterning preparation process diagram provided in Example 2 of the present invention.
[0050] See also Figure 2 and Figure 3 , the preparation method comprises:
[0051] S210 , providing a substrate.
[0052] In an embodiment of the present invention, the substrate may be a silicon substrate, a glass substrate or a metal substrate, or a composite substrate including a multilayer structure, which is not limited in the embodiment of the present invention. After providing the substrate, the substrate may be pre-processed, for example, polishing, cleaning, preheating, etc., which is not limited in the embodiment of the present invention.
[0053] S220, preparing an etching-resistant layer and an anti-reflection coating on one side of the substrate, and preparing a first photoresist layer and a second photoresist layer on the anti-reflection coating, respectively.
[0054] For example, Figure 3In the embodiment shown, the etching-resistant layer 20 and the anti-reflection coating 30 are respectively prepared on one side of the substrate 10 by a spin coating process, that is, the etching-resistant layer 20 is located on the side of the anti-reflection coating 30 close to the substrate 10. Among them, the anti-reflection coating 30 is mainly used to reduce the reflection of light, and then in the subsequent photolithography process, the photolithography quality can be improved. The etching-resistant layer 20 is located at the position closest to the substrate 10, and then the etching-resistant layer 20 is used as a height buffer layer to ensure that the heights of different patterns are consistent when different patterns are transferred to the etching-resistant layer 20. After the etching-resistant layer 20 and the anti-reflection coating 30 are prepared, the first photoresist layer 40 and the second photoresist layer 50 are spin-coated on the anti-reflection coating 30, respectively, wherein the photosensitivity of the first photoresist layer 40 is greater than the photosensitivity of the second photoresist layer 50.
[0055] It should be noted that, in the embodiment of the present invention, after the first photoresist layer 40 and the second photoresist layer 50 are prepared, the first photoresist layer 40 and the second photoresist layer 50 may be cured by a curing process to facilitate subsequent exposure and development processes.
[0056] S230, exposing the first photoresist layer and the second photoresist layer simultaneously by using an exposure process, and developing the layers by using a developer.
[0057] Specifically, the first photoresist layer 40 and the second photoresist layer 50 may be exposed at the same position by a single exposure process, and developed under the same development conditions to form multiple patterned graphics on the first photoresist layer 40 and the second photoresist layer 50. For example, Figure 3In the illustrated embodiment, the first photoresist layer 40 is located on the side of the second photoresist layer 50 close to the substrate 10, and the photosensitivity of the first photoresist layer 40 is greater than that of the second photoresist layer 50. After development using the same exposure process and the same development conditions, since the photosensitivity of the first photoresist layer 40 is greater than that of the second photoresist layer 50, the bottom area of the pattern formed on the first photoresist layer 40 is smaller than the bottom area of the pattern formed on the second photoresist layer 50. For example, the pattern formed on the first photoresist layer 40 is the first pattern 410, and the pattern formed on the second photoresist layer 50 is the second pattern 510. The width distance of the first pattern 410 is the same as the spacing between the second patterns 510, and is also 1 / 4 of the period. The cross section of the first pattern 410 is a uniform rectangle, and the cross section of the second pattern 510 is a trapezoid that is narrow at the top and wide at the bottom, wherein the area of the bottom of the second pattern 510 is larger than the bottom area of the first pattern 410. In other words, the vertical projection of the pattern (second pattern 510) formed on the second photoresist layer 50 on the substrate 10 covers the vertical projection of the pattern (first pattern 410) formed on the first photoresist layer 40 on the substrate 10. In addition, since the first photoresist layer 40 and the second photoresist layer 50 are exposed simultaneously in the same exposure process, that is, the first photoresist layer 40 and the second photoresist layer 50 use the same exposure mask, the first pattern 410 and the second pattern 510 are formed at the same position, such as Figure 3 As shown, the central axes of the first pattern 410 and the second pattern 510 coincide, that is, the first pattern 410 is located at the center of the second pattern 510. In this way, by utilizing the different photosensitivity of the first photoresist layer 40 and the second photoresist layer 50, self-alignment of the first pattern 410 and the second pattern 510 is achieved during the development process through a single exposure process, thereby simplifying the process steps and improving production efficiency.
[0058] S240, coating is performed by magnetron sputtering or electron beam evaporation.
[0059] Specifically, magnetron sputtering or electron beam evaporation can be used to coat the second photoresist layer 50, so as to form a first coating structure 610 directly above the pattern (second pattern 510) formed by the second photoresist layer 50, and a second coating structure 620 is formed at the interval position of the pattern (first pattern 410) formed by the first photoresist layer 40. It should be noted that during the coating process, the coating material is flattened directly above the second pattern 510. Since there is an interval between two adjacent second patterns 510, part of the coating material is located on the anti-reflective coating 30, and the second coating structure 620 is finally formed by the coating material. The second coating structure 620 is located at the center of the interval between the adjacent second patterns 510, and is also located at the center of the interval between the adjacent first patterns 410. It can be understood that the coating material can be one of a metal, a metal oxide or a non-metal oxide, and the present invention is not limited to this, and those skilled in the art can set it as needed.
[0060] It should also be noted that the coating is performed by magnetron sputtering or electron beam evaporation in the embodiment of the present invention, which can improve production efficiency compared with the coating method using atomic layer deposition in the prior art.
[0061] S250, removing the pattern formed by the second photoresist layer and the first coating structure by using a stripping process.
[0062] Specifically, the Lift-Off process can be used to peel off the pattern (second pattern 510) formed by the second photoresist layer 50 from the surface of the first photoresist layer 40 through the cleaning solution of the second photoresist layer 50. The first coating structure 610 is located directly above the second pattern 510. Therefore, in the process of peeling off the second photoresist layer 50, the first coating structure 610 is also peeled off. Figure 3As shown, the pattern (first pattern 410) formed by the first photoresist layer 40 and the second coating structure 620 located between the adjacent first patterns 410 are retained, thereby forming a double pattern mask consisting of the first pattern 410 and the second coating structure 620. It can be understood that the lift-off stripping process used in the embodiment of the present invention is to remove the entire second photoresist layer 50. Compared with the method of opening the mandrel to retain the side wall in the prior art, the phenomenon of side wall collapse can be avoided, thereby improving the production yield. In addition, in the present application, multiple patterned graphics are formed by using photoresist layers with different photosensitivity, and the final double pattern mask is obtained by subsequent coating processes and stripping, without the need to use multiple etching processes, thereby optimizing the process flow, and because after the exposure and development processes, the width distance of the first pattern 410 is the same as the spacing between the second patterns 420, and is also 1 / 4 of the period, and then the final double pattern mask is obtained by the stripping process, thereby achieving a reduction in the period of double patterning (when the double pattern mask is finally formed, the period is reduced by half).
[0063] S260, transferring the mask pattern of the double pattern mask to the anti-reflective coating and the etching resistant layer.
[0064] An etching process is adopted to etch downwards using the double pattern mask as a mask, so as to transfer the mask pattern of the double pattern mask to the anti-reflective coating 30 and the etching resistant layer 20, thereby completing the self-aligned double patterning process.
[0065] S270, transferring the patterns of the anti-reflective coating and the etching resistance layer to the substrate.
[0066] The anti-reflective coating and the etching resistant layer are used as masks for downward etching, so that the patterns of the reflective coating and the etching resistant layer are transferred to the substrate, thereby obtaining a product with a half cycle.
[0067] It should be noted that in order to achieve a highly consistent double pattern when finally transferred to the substrate 10, the embodiment of the present invention sets the etching-resistant layer 20 for height buffering. In other embodiments, the etching-resistant layer 20 may not be set, so that a highly inconsistent double pattern is obtained when transferred to the substrate 10. Those skilled in the art can set it as needed.
[0068] In summary, the embodiment of the present invention realizes self-alignment of double patterning during exposure and development by utilizing photoresist layers with different photosensitivity, and adopts a coating method of electron beam evaporation or magnetron sputtering to replace the coating method of atomic layer deposition, thereby improving production efficiency to a certain extent. In addition, a Lift-Off stripping process is also used to remove the entire second photoresist layer. Compared with the method of opening the mandrel to retain the side wall in the prior art, the phenomenon of side wall collapse can be avoided, thereby improving production yield. At the same time, the etching-resistant layer is used as a height buffer layer to perform height buffering, so that a highly consistent double pattern is obtained when it is finally transferred to the substrate, which optimizes the process flow, simplifies the process steps, and makes the process application range wider.
[0069] Embodiment 3
[0070] Figure 4 is a schematic flow chart of another self-aligned multiple patterning preparation method provided in Embodiment 3 of the present invention, Figure 5 FIG. 1 is another self-aligned multiple patterning process diagram provided by Embodiment 3 of the present invention. Figure 4 and Figure 5 , the preparation method comprises:
[0071] S310 , providing a substrate.
[0072] In an embodiment of the present invention, the substrate may be a silicon substrate, a glass substrate or a metal substrate, or a composite substrate including a multilayer structure, which is not limited in the embodiment of the present invention. After providing the substrate, the substrate may be pre-processed, for example, polishing, cleaning, preheating, etc., which is not limited in the embodiment of the present invention.
[0073] S320, preparing an etching resistant layer and an etching stop layer on one side of the substrate, and preparing a first photoresist layer and a second photoresist layer on the etching stop layer respectively.
[0074] For example, Figure 5In the embodiment shown, the etching-resistant layer 20 is first formed on one side of the substrate 10 by a spin coating process, and then the etching stop layer 70 can be prepared on the etching-resistant layer 20 by a coating process, that is, the etching-resistant layer 20 is located on the side of the etching stop layer 70 close to the substrate 10. It can be understood that in other embodiments, the etching-resistant layer 20 can also be prepared by a coating process, but considering the process cost and process difficulty, it is preferred to prepare the etching-resistant layer 20 by a spin coating process. Among them, the etching stop layer 70 is mainly used to protect the film layer below from being further etched during the etching process, thereby ensuring the integrity of the film layer below. The etching-resistant layer 20 is located at the position closest to the substrate 10, and then the etching-resistant layer 20 and the etching stop layer 70 are used as a height buffer layer, which can ensure that when different patterns are transferred to the etching-resistant layer 20 and the etching stop layer, the height of different patterns remains consistent. After the etching resistance layer 20 and the etching stop layer 70 are prepared, the first photoresist layer 40 and the second photoresist layer 50 are spin-coated on the etching stop layer 70 , respectively, wherein the photosensitivity of the first photoresist layer 40 is lower than that of the second photoresist layer 50 .
[0075] It should be noted that, in the embodiment of the present invention, after the first photoresist layer 40 and the second photoresist layer 50 are prepared, the first photoresist layer 40 and the second photoresist layer 50 may be cured by a curing process to facilitate subsequent exposure and development processes.
[0076] S330, exposing the first photoresist layer and the second photoresist layer simultaneously by using an exposure process, and developing the layers by using a developer.
[0077] Specifically, the first photoresist layer 40 and the second photoresist layer 50 may be exposed at the same position by a single exposure process, and developed under the same development conditions to form multiple patterned graphics on the first photoresist layer 40 and the second photoresist layer 50. For example, Figure 5In the illustrated embodiment, the first photoresist layer 40 is located on the side of the second photoresist layer 50 close to the substrate 10, and the photosensitivity of the first photoresist layer 40 is less than that of the second photoresist layer 50. After development using the same exposure process and the same development conditions, since the photosensitivity of the first photoresist layer 40 is less than that of the second photoresist layer 50, the bottom area of the pattern formed on the first photoresist layer 40 is greater than the bottom area of the pattern formed on the second photoresist layer 50. For example, the pattern formed on the first photoresist layer 40 is the third pattern 420, and the pattern formed on the second photoresist layer 50 is the fourth pattern 520. The spacing between the third patterns 420 is the same as the width of the fourth pattern 520, and is 1 / 8 of the period at the same time. The cross-sections of the third pattern 420 and the fourth pattern 520 are both uniform rectangles, wherein the bottom area of the third pattern 420 is greater than the bottom area of the fourth pattern 520. In other words, the vertical projection of the pattern (third pattern 420) formed on the first photoresist layer 40 on the substrate 10 covers the vertical projection of the pattern (fourth pattern 520) formed on the second photoresist layer 50 on the substrate 10. In addition, since the first photoresist layer 40 and the second photoresist layer 50 are exposed simultaneously in the same exposure process, that is, the first photoresist layer 40 and the second photoresist layer 50 use the same exposure mask, the third pattern 420 and the fourth pattern 520 are formed at the same position. Figure 5 As shown, the central axis of the third pattern 420 coincides with that of the fourth pattern 520, that is, the fourth pattern 520 is located at the center of the third pattern 420. In this way, by utilizing the different photosensitivity of the first photoresist layer 40 and the second photoresist layer 50, self-alignment of the third pattern 420 and the fourth pattern 520 is achieved during the development process through a single exposure process, thereby simplifying the process steps and improving production efficiency.
[0078] S340, coating is performed by atomic layer deposition.
[0079] Specifically, the coating can be performed directly above the second photoresist layer 50 by atomic layer deposition, so as to form a third coating structure 630 at the top of the double pattern (the combined structure of the third pattern 420 and the fourth pattern 520) formed by the first photoresist layer 40 and the second photoresist layer 50, form a fourth coating structure 640 at the sidewall of the double pattern, and form a fifth coating structure 650 at the interval position of the pattern (third pattern 420) formed by the first photoresist layer 40. It should be noted that during the coating process, the coating material is spread directly above the double pattern, that is, there is coating material at the top and sidewall of the double pattern. It can be understood that the top and sidewall of the double pattern are connected to each other to form the outer surface of the double pattern. In addition, since there is a gap between two adjacent double patterns, there is a part of the coating material located on the etching stop layer 70, and the part of the coating material finally forms the fifth coating structure 650, and the fifth coating structure 650 is located at the center of the two adjacent double patterns. It is understandable that the coating material may be one of metal, metal oxide or non-metal oxide, and the present invention is not limited thereto, and those skilled in the art may set it as required.
[0080] S350, etching the third coating structure and the fifth coating structure using an etching process.
[0081] Specifically, an etching process is adopted to utilize the anisotropic etching mechanism of an inductively coupled plasma etcher or a reactive ion etcher to etch away the third coating structure 630 located at the top of the double pattern and the fifth coating structure 650 located between the third patterns 420. This opens the top of the coating structure and exposes the core axis while retaining the fourth coating structure 640 located at the side wall of the double pattern, thereby facilitating the next step of etching.
[0082] S360, using the second coating structure as a mask, etching downward the double pattern to form a quadruple pattern mask.
[0083] Since the third coating structure 630 located at the top of the double pattern is etched away, only the fourth coating structure 640 located at the sidewall of the double pattern is retained, and then the double pattern is further etched using the fourth coating structure 640 as a mask, so as to form Figure 5 A quadruple patterned mask having a quadruple pattern is shown.
[0084] It should be noted that after etching away the fifth coating structure 650 between adjacent double patterns, since the fifth coating structure 650 is located on the etching stop layer 70, the etching stop layer 70 is used to protect the underlying film layer during the process of etching to form a quadruple pattern mask.
[0085] S370, transferring the mask pattern of the quadruple-pattern mask to the etching stop layer.
[0086] Specifically, an etching process is adopted to etch downwards with the quadruple-pattern mask as a mask, thereby transferring the mask pattern of the quadruple-pattern mask to the etching stop layer 70. Since the spacing between the third patterns 420 is the same as the width distance of the fourth pattern 520 and is also 1 / 8 of the period, a reduction in the period of quadruple patterning is achieved (when the quadruple-pattern mask is finally formed, the period is reduced by four times).
[0087] It should be noted that in order to achieve a highly consistent quadruple pattern when finally transferred to the substrate 10, the embodiment of the present invention sets the etching-resistant layer 20 and the etching stop layer 70 for height buffering. In other embodiments, the etching-resistant layer 20 and the etching stop layer 70 may not be set, so that a highly inconsistent quadruple pattern is obtained when transferred to the substrate 10. Those skilled in the art can set it as needed.
[0088] S280, transferring the patterns of the etching resistance layer and the etching stop layer to the substrate.
[0089] Etching is performed downwards using the patterns of the etch-resistant layer and the etch-stop layer as a mask, thereby transferring the patterns of the etch-resistant layer and the etch-stop layer to the substrate to obtain a final product.
[0090] In summary, the embodiment of the present invention realizes self-alignment of double patterning during exposure and development by utilizing photoresist layers with different photosensitivity, which greatly avoids the need for multiple coating and etching processes in the original process, and then assists in obtaining a quadruple pattern mask through the coating process and the etching process. At the same time, the etching-resistant layer and the etching stop layer are used as a height buffer layer to perform height buffering, thereby obtaining a highly consistent quadruple patterned mandrel structure, optimizing the process flow, simplifying the process steps, and making the process application range wider.
[0091] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. A method for preparing self-aligned multiple patterning, characterized in that: include: providing a substrate; Preparing a first photoresist layer and a second photoresist layer on one side of the substrate, respectively, wherein the photosensitivity of the first photoresist layer is different from the photosensitivity of the second photoresist layer; The first photoresist layer and the second photoresist layer are exposed and developed to complete self-alignment of multiple patterns on the first photoresist layer and the second photoresist layer.
2. The preparation method according to claim 1, characterized in that: The first photoresist layer is located on a side of the second photoresist layer close to the substrate, and the photosensitivity of the first photoresist layer is greater than the photosensitivity of the second photoresist layer; The exposing and developing the first photoresist layer and the second photoresist layer comprises: The first photoresist layer and the second photoresist layer are simultaneously exposed by an exposure process, and developed by a developer to form multiple patterned graphics on the first photoresist layer and the second photoresist layer, and the vertical projection of the pattern formed on the second photoresist layer on the substrate covers the vertical projection of the pattern formed on the first photoresist layer on the substrate.
3. The preparation method according to claim 2, characterized in that: After the first photoresist layer and the second photoresist layer are exposed and developed, the method further includes: The coating is performed by magnetron sputtering or electron beam evaporation to form a first coating structure directly above the pattern formed by the second photoresist layer and a second coating structure at intervals between the patterns formed by the first photoresist layer.
4. The preparation method according to claim 3, characterized in that: After the coating is performed by magnetron sputtering or electron beam evaporation, the method further comprises: The pattern formed by the second photoresist layer and the first coating structure are removed by a stripping process, and the pattern formed by the first photoresist layer and the second coating structure are retained to form a double pattern mask.
5. The preparation method according to claim 4, characterized in that: Before respectively preparing the first photoresist layer and the second photoresist layer on one side of the substrate, the method further includes: Preparing an anti-reflective coating and an etching resistant layer on one side of the substrate; After removing the pattern formed by the second photoresist layer and the first coating structure by the stripping process and retaining the pattern formed by the first photoresist layer and the second coating structure, the method further includes: The mask pattern of the double pattern mask is transferred to the anti-reflective coating layer and the etching resistant layer.
6. The preparation method according to claim 1, characterized in that: The first photoresist layer is located on a side of the second photoresist layer close to the substrate, and the photosensitivity of the first photoresist layer is lower than that of the second photoresist layer; The exposing and developing the first photoresist layer and the second photoresist layer comprises: The first photoresist layer and the second photoresist layer are simultaneously exposed by an exposure process, and developed by a developer to form multiple patterned graphics on the first photoresist layer and the second photoresist layer, and the vertical projection of the pattern formed on the first photoresist layer on the substrate covers the vertical projection of the pattern formed on the second photoresist layer on the substrate.
7. The preparation method according to claim 6, characterized in that: After the first photoresist layer and the second photoresist layer are exposed and developed, the method further includes: Atomic layer deposition is used for coating to form a third coating structure on the top of the double pattern formed by the first photoresist layer and the second photoresist layer, a fourth coating structure is formed on the sidewall of the double pattern, and a fifth coating structure is formed at the interval position of the pattern formed by the first photoresist layer, wherein the top and the sidewall are interconnected to form the outer surface of the double pattern.
8. The preparation method according to claim 7, characterized in that: When the coating is carried out by atomic layer deposition, it also includes: The third coating structure and the fifth coating structure are etched by an etching process.
9. The preparation method according to claim 8, characterized in that: After etching the third coating structure and the fifth coating structure using an etching process, the method further includes: The fourth coating structure is used as a mask to etch downward the double pattern to form a quadruple pattern mask.
10. The preparation method according to claim 9, characterized in that: Before respectively preparing the first photoresist layer and the second photoresist layer on one side of the substrate, the method further includes: Prepare an etching stop layer and an etching resistance layer on one side of the substrate; After etching the double pattern using the fourth coating structure as a mask to form a quadruple pattern mask, the method further includes: The mask pattern of the quadruple-pattern mask is transferred to the etch stop layer.