Narrow groove secondary imaging method
Through the narrow groove secondary imaging method, the trench size is accurately controlled in the LELE double exposure process by using the silicon oxide sidewall growth technology, which solves the problem that photoresist cannot develop cleanly in the traditional process, and realizes the preparation of small-sized trenches The formation of high-density groove structure ensures the quality and success rate of lithography.
Patent Information
- Application Number
- CN202411521958.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2024-12-10
AI Technical Summary
The traditional LELE double exposure process has the problem that the photoresist cannot develop cleanly when preparing narrow groove structures, resulting in the inability to prepare small-sized groove structures.
By using the narrow trench secondary imaging method, the trench width is accurately controlled by growing silicon nitride and silicon oxide layers on the substrate, using the silicon oxide sidewall growth method, first forming the first wide trench and narrow trench, and then Fill and form a second wide groove and a narrow groove, and finally remove the fill layer to form a high density groove structure.
The preparation of small-size trenches and the guarantee of lithography quality are achieved, the trench density is improved, and the lithography success rate can reach 100%. Narrow trenches with widths as low as 10nm are prepared without reducing the exposure amount.
Smart Images
Figure CN119108268A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of double patterning, and in particular to a narrow groove secondary imaging method. Background Art
[0002] Double patterning is also called double exposure or double exposure. The idea is to divide the data of the same graphic layer into two times or two masks for separate imaging. With the development of integrated circuit manufacturing technology, lithography technology faces huge challenges, and the requirements for layout design are more stringent. In order to ensure the quality of graphic transfer, the design rules tend to arrange the lines of the same layer of graphics in one direction. When the spacing between lines arranged in the same direction is close to 80nm, it has reached the limit of single exposure of 193nm immersion lithography machine; if the line spacing is less than 80nm, double or multiple patterning technology must be used before more advanced lithography machines are applied to mass production.
[0003] At present, there are two most common double patterning technologies in the industry, namely Self-Aligned Double Patterning (SADP) technology and Litho-Eich-Litho-Etch (LELE) double patterning technology. In the traditional LELE double exposure process, the resolution is limited to the minimum line width plus the size of the spacing. The line width can be adjusted by modifying the photolithography conditions to make the lines thinner. First, the lines are made smaller through photolithography technology, and then etched onto a hard mask, thereby obtaining a structure with a small line width but a large spacing; after the first exposure is completed, it is etched onto a hard mask, and fine lines can be obtained, but the spacing of the pattern cannot be doubled. Subsequently, the line width is made the same as the first width through a second photolithography, and then etched to make the lines denser and the pattern more compact. However, this method has certain limitations. Although photolithography can obtain thinner lines by increasing the exposure, it is not applicable to narrower grooves. In order to obtain narrower grooves, the exposure needs to be reduced, but the reduced exposure will cause the photoresist to not be developed cleanly, so smaller groove structures cannot be prepared.
[0004] In view of this, the present invention is proposed. Summary of the invention
[0005] The object of the present invention is to provide a narrow groove secondary imaging method, which can prepare small-sized groove patterns and accurately control the width of the grooves.
[0006] The present invention provides a narrow groove secondary imaging method, comprising the following steps:
[0007] S1: growing a first silicon oxide layer on the silicon nitride layer of the substrate, performing photolithography and etching to form a first wide groove pattern;
[0008] S2: Continue to grow the first silicon oxide layer, and etch the silicon oxide grown on the silicon nitride layer to form a first narrow groove pattern;
[0009] S3: filling the first narrow groove pattern, growing a second silicon oxide layer on the filling layer, photolithography and etching to form a second wide groove pattern;
[0010] S4: Continue to grow a second silicon oxide layer, and etch the silicon oxide grown on the fill layer to form a second narrow groove pattern;
[0011] S5: etching the fill-up layer and the first silicon oxide layer to remove the second silicon oxide layer and the fill-up layer, thereby forming a high-density groove structure having a first narrow groove pattern and a second narrow groove pattern.
[0012] In step S1, a silicon nitride layer is first grown on the substrate in a conventional manner, and the thickness of the silicon nitride layer can be 50-150nm; then, a first silicon oxide layer is grown on the silicon nitride layer in a conventional manner, and the thickness of the first silicon oxide layer can be 100-300nm; through photolithography and etching, a first wide groove pattern can be formed on the first silicon oxide layer.
[0013] There is no strict restriction on the specific shape of the first wide groove pattern, which can be reasonably set according to design requirements; specifically, the first wide groove pattern includes a plurality of first wide grooves that are parallel and spaced apart, and the width of the first wide groove can be 30-150nm. The groove has a large size, so there is no need to reduce the exposure, and the photoresist can be developed cleanly.
[0014] In step S2, the first silicon oxide layer continues to grow. At this time, the sidewall of the first silicon oxide layer grows toward the first wide trench, so that the width of the first wide trench becomes smaller to form a first narrow trench; by controlling the growth temperature and time of the first silicon oxide layer, the width of the first narrow trench can be precisely controlled.
[0015] There is no strict restriction on the growth temperature and time of the first silicon oxide layer, which can be reasonably set according to the design requirements of the groove; specifically, the growth temperature of the first silicon oxide layer can be 600-1000°C, and the growth time can be 30s-3min. Correspondingly, the first narrow groove pattern includes a plurality of parallel and spaced first narrow grooves, and the width of the first narrow groove can be 10-50nm. In the above manner, narrow grooves with a width as low as 10nm can be prepared, which is conducive to the preparation of a high-density groove structure with a small-sized groove pattern.
[0016] In step S3, the first narrow groove pattern may be filled by spin coating SOC, and there is no strict restriction on the thickness of the filling layer. The thickness of the filling layer (referring to the height of the portion above the first silicon oxide layer) is, for example, 50-100 nm.
[0017] After filling, a second silicon oxide layer is grown on the filling layer in a conventional manner, and the thickness of the second silicon oxide layer can be 100-300nm; a second wide groove pattern can be formed on the second silicon oxide layer by photolithography and etching. There is no strict restriction on the specific shape of the second wide groove pattern, which can be reasonably set according to design requirements. The second wide groove pattern can be the same as or different from the first wide groove pattern; specifically, the second wide groove pattern includes a plurality of second wide grooves arranged in parallel and at intervals, and the width of the second wide groove can be 30-150nm. The second wide groove can be staggered with the first narrow groove, so as to facilitate the improvement of the groove density.
[0018] In step S4, the second silicon oxide layer continues to grow, and the sidewall of the second silicon oxide layer grows toward the second wide groove, so that the width of the second wide groove becomes smaller to form a second narrow groove; similarly, by controlling the growth temperature and time of the second silicon oxide layer, the width of the second narrow groove can be precisely controlled.
[0019] There is no strict restriction on the growth temperature and time of the second silicon oxide layer, which can be reasonably set according to the design requirements of the groove; specifically, the growth temperature of the second silicon oxide layer can be 600-1000°C, and the growth time can be 30s-3min. Correspondingly, the second narrow groove pattern includes a plurality of second narrow grooves arranged in parallel and at intervals, the width of the second narrow groove can be 10-50nm, the width of the second narrow groove can be the same as or different from the width of the first narrow groove, and the second narrow groove and the first narrow groove are staggered, so as to facilitate the improvement of the groove density.
[0020] In step S5, the filling layer and the first silicon oxide layer are first etched to transfer the second narrow groove pattern to the first silicon oxide layer; then, the second silicon oxide layer and the filling layer are removed to expose the first narrow groove pattern, thereby forming a high-density groove structure having the first narrow groove pattern and the second narrow groove pattern.
[0021] The narrow groove secondary imaging method of the present invention adopts a silicon oxide layer as a pattern transfer layer, and utilizes the growth of silicon oxide side walls to accurately control the size of the groove. It can prepare a narrow groove with a width as low as 10nm without reducing the exposure amount, thereby ensuring the quality of lithography and realizing the preparation of small-sized grooves. At the same time, after preparing the first wide groove pattern, the second wide groove pattern is filled and prepared, thereby improving the groove density, and the lithography success rate can be as high as 100%. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0023] Figure 1 is a process flow chart of the narrow groove secondary imaging method of the present invention;
[0024] Figure 2 is an electron microscope image of the first wide trench of Example 1;
[0025] Figure 3 is an electron microscope image of the first narrow groove of Example 1;
[0026] Figure 4 This is an electron microscope image of the first narrow groove of Example 2.
[0027] Description of reference numerals:
[0028] 1: substrate; 2: silicon nitride layer; 3: first silicon oxide layer; 4: first wide trench; 5: first narrow trench; 6: filling layer; 7: second silicon oxide layer; 8: second wide trench; 9: second narrow trench. DETAILED DESCRIPTION
[0029] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.
[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0032] Example 1
[0033] Combination Figure 1As shown, the narrow groove secondary imaging method of this embodiment includes the following steps:
[0034] S1: Preparation of the first wide groove pattern
[0035] First, a silicon nitride layer 2 is grown on the substrate 1, and the thickness of the silicon nitride layer 2 is 150 nm.
[0036] Subsequently, a first silicon oxide layer 3 is grown on the silicon nitride layer 2, and the thickness of the first silicon oxide layer 3 is 300 nm. By photolithography and etching, a first wide groove pattern is formed on the first silicon oxide layer 3, and the first wide groove pattern consists of a plurality of first wide grooves 4 arranged in parallel and spaced apart, and the width of the first wide groove 4 is 133.9 nm (see Figure 2 ).
[0037] S2: Preparation of the first narrow groove pattern
[0038] The first silicon oxide layer 3 is allowed to continue to grow at 1000° C. for 500 seconds, and then the silicon oxide grown on the silicon nitride layer 2 is etched to form a first narrow groove pattern on the first silicon oxide layer 3; the first narrow groove pattern is composed of a plurality of first narrow grooves 5 arranged in parallel and at intervals, and the width of the first narrow groove 5 is 26.2 nm (see Figure 3 ).
[0039] S3: Preparation of the second wide groove pattern
[0040] SOC is spin-coated on the first narrow groove pattern to form a filling layer 6, and the thickness of the filling layer 6 is 100 nm.
[0041] Subsequently, a second silicon oxide layer 7 is grown on the fill layer 6, and the thickness of the second silicon oxide layer 7 is 300 nm. Photolithography and etching are performed to form a second wide groove pattern on the second silicon oxide layer 7; the second wide groove pattern is composed of a plurality of second wide grooves 8 arranged in parallel and at intervals, the width of the second wide grooves 8 is 30 nm, and the second wide grooves 8 and the first wide grooves 4 are arranged alternately.
[0042] S4: Preparation of the second narrow groove pattern
[0043] The second silicon oxide layer 7 is allowed to continue growing at 1000° C. for 500 seconds, and then the silicon oxide grown on the filling layer 6 is etched to form a second narrow groove pattern on the second silicon oxide layer 7; the second narrow groove pattern consists of a plurality of parallel and spaced second narrow grooves 9, the width of the second narrow groove 9 is 30 nm, and the second narrow groove 9 is staggered with the first narrow groove 5.
[0044] S5: Preparation of high-density groove structures
[0045] The filling layer 6 and the first silicon oxide layer 3 are etched to transfer the second narrow groove pattern to the first silicon oxide layer 3; then, the second silicon oxide layer 7 and the filling layer 6 are removed to expose the first narrow groove pattern on the first silicon oxide layer 3, thereby obtaining a high-density groove structure having the first narrow groove pattern and the second narrow groove pattern.
[0046] Example 2
[0047] Combination Figure 1 As shown, the narrow groove secondary imaging method of this embodiment includes the following steps:
[0048] S1: Preparation of the first wide groove pattern
[0049] First, a silicon nitride layer 2 is grown on the substrate 1, and the thickness of the silicon nitride layer 2 is 50 nm.
[0050] Subsequently, a first silicon oxide layer 3 is grown on the silicon nitride layer 2, and the thickness of the first silicon oxide layer 3 is 100 nm. Photolithography and etching are performed to form a first wide groove pattern on the first silicon oxide layer 3, and the first wide groove pattern consists of a plurality of first wide grooves 4 arranged in parallel and at intervals, and the width of the first wide groove 4 is 180 nm.
[0051] S2: Preparation of the first narrow groove pattern
[0052] The first silicon oxide layer 3 is allowed to continue to grow for 30 seconds at 600° C., and then the silicon oxide grown on the silicon nitride layer 2 is etched to form a first narrow groove pattern on the first silicon oxide layer 3; the first narrow groove pattern is composed of a plurality of first narrow grooves 5 arranged in parallel and at intervals, and the width of the first narrow groove 5 is 42.5 nm (see Figure 4 ).
[0053] S3: Preparation of the second wide groove pattern
[0054] SOC is spin-coated on the first narrow groove pattern to form a filling layer 6, and the thickness of the filling layer 6 is 50 nm.
[0055] Subsequently, a second silicon oxide layer 7 is grown on the fill layer 6, and the thickness of the second silicon oxide layer 7 is 100 nm. Photolithography and etching are performed to form a second wide groove pattern on the second silicon oxide layer 7; the second wide groove pattern consists of a plurality of second wide grooves 8 arranged in parallel and at intervals, the width of the second wide grooves 8 is 180 nm, and the second wide grooves 8 and the first wide grooves 4 are arranged alternately.
[0056] S4: Preparation of the second narrow groove pattern
[0057] The second silicon oxide layer 7 is allowed to continue growing at 600°C for 30 seconds, and then the silicon oxide grown on the fill layer 6 is etched to form a second narrow groove pattern on the second silicon oxide layer 7; the second narrow groove pattern consists of a plurality of parallel and spaced second narrow grooves 9, the width of the second narrow groove 9 is 40nm, and the second narrow groove 9 is staggered with the first narrow groove 5.
[0058] S5: Preparation of high-density groove structures
[0059] The filling layer 6 and the first silicon oxide layer 3 are etched to transfer the second narrow groove pattern to the first silicon oxide layer 3; then, the second silicon oxide layer 7 and the filling layer 6 are removed to expose the first narrow groove pattern on the first silicon oxide layer 3, thereby obtaining a high-density groove structure having the first narrow groove pattern and the second narrow groove pattern.
[0060] Example 3
[0061] Combination Figure 1 As shown, the narrow groove secondary imaging method of this embodiment includes the following steps:
[0062] S1: Preparation of the first wide groove pattern
[0063] First, a silicon nitride layer 2 is grown on the substrate 1, and the thickness of the silicon nitride layer 2 is 100 nm.
[0064] Subsequently, a first silicon oxide layer 3 is grown on the silicon nitride layer 2, and the thickness of the first silicon oxide layer 3 is 200 nm. Photolithography and etching are performed to form a first wide groove pattern on the first silicon oxide layer 3, and the first wide groove pattern consists of a plurality of first wide grooves 4 arranged in parallel and at intervals, and the width of the first wide groove 4 is 90 nm.
[0065] S2: Preparation of the first narrow groove pattern
[0066] The first silicon oxide layer 3 is allowed to continue growing at 800° C. for 15 seconds, and then the silicon oxide grown on the silicon nitride layer 2 is etched to form a first narrow groove pattern on the first silicon oxide layer 3; the first narrow groove pattern consists of a plurality of parallel and spaced first narrow grooves 5, and the width of the first narrow groove 5 is 10 nm.
[0067] S3: Preparation of the second wide groove pattern
[0068] SOC is spin-coated on the first narrow groove pattern to form a filling layer 6, and the thickness of the filling layer 6 is 80 nm.
[0069] Subsequently, a second silicon oxide layer 7 is grown on the fill layer 6, and the thickness of the second silicon oxide layer 7 is 200 nm. Photolithography and etching are performed to form a second wide groove pattern on the second silicon oxide layer 7; the second wide groove pattern is composed of a plurality of second wide grooves 8 arranged in parallel and at intervals, the width of the second wide grooves 8 is 90 nm, and the second wide grooves 8 and the first wide grooves 4 are arranged alternately.
[0070] S4: Preparation of the second narrow groove pattern
[0071] The second silicon oxide layer 7 is allowed to continue growing at 800°C for 15 seconds, and then the silicon oxide grown on the filling layer 6 is etched to form a second narrow groove pattern on the second silicon oxide layer 7; the second narrow groove pattern consists of a plurality of parallel and spaced second narrow grooves 9, the width of the second narrow groove 9 is 10nm, and the second narrow groove 9 is staggered with the first narrow groove 5.
[0072] S5: Preparation of high-density groove structures
[0073] The filling layer 6 and the first silicon oxide layer 3 are etched to transfer the second narrow groove pattern to the first silicon oxide layer 3; then, the second silicon oxide layer 7 and the filling layer 6 are removed to expose the first narrow groove pattern on the first silicon oxide layer 3, thereby obtaining a high-density groove structure having the first narrow groove pattern and the second narrow groove pattern.
[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A narrow groove secondary imaging method, characterized in that: The steps include: S1: growing a first silicon oxide layer on the silicon nitride layer of the substrate, performing photolithography and etching to form a first wide groove pattern; S2: Continue to grow the first silicon oxide layer, and etch the silicon oxide grown on the silicon nitride layer to form a first narrow groove pattern; S3: filling the first narrow groove pattern, growing a second silicon oxide layer on the filling layer, photolithography and etching to form a second wide groove pattern; S4: Continue to grow a second silicon oxide layer, and etch the silicon oxide grown on the fill layer to form a second narrow groove pattern; S5: etching the fill-up layer and the first silicon oxide layer to remove the second silicon oxide layer and the fill-up layer, thereby forming a high-density groove structure having a first narrow groove pattern and a second narrow groove pattern.
2. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S1, the thickness of the silicon nitride layer is 50-150 nm.
3. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S1, the thickness of the first silicon oxide layer is 100-300 nm; the width of the first wide trench is 30-150 nm.
4. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S2, the growth temperature of the first silicon oxide layer is 600-1000°C, and the growth time is 30s-3min.
5. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S2, the width of the first narrow groove is 10-50 nm.
6. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S3, the filling is performed by spin coating SOC; the thickness of the filling layer is 50-100 nm.
7. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S3, the thickness of the second silicon oxide layer is 100-300 nm; the width of the second wide trench is 30-150 nm.
8. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S4, the growth temperature of the second silicon oxide layer is 600-1000° C., and the growth time is 30 s-3 min.
9. The narrow groove secondary imaging method according to claim 1, characterized in that: In step S4, the width of the second narrow groove is 10-50 nm.
10. The narrow groove secondary imaging method according to claim 1, characterized in that: The first narrow groove pattern includes a plurality of first narrow grooves arranged in parallel and at intervals, and the second narrow groove pattern includes a plurality of second narrow grooves arranged in parallel and at intervals, and the second narrow grooves are arranged alternately with the first narrow grooves.