Method of forming linear pattern in semiconductor device
By forming a multi-layer photoresist layer in a semiconductor device and filling a specific material, the roughness problem of photoresist layer caused by standing wave effect is solved, and a linear pattern with a smaller roughness is realized, and the contour quality of the pattern is improved.
Patent Information
- Application Number
- CN202411039341.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-10-16
- Filing Date
- 2024-07-31
- Publication Date
- 2025-04-18
AI Technical Summary
In the photomicrograph technology process, the standing wave effect leads to the problem of line edge roughness and line width roughness of the photoresist layer, which is difficult for prior art such as hard masking layers and baking processes to completely solve.
By forming a multi-layer photoresist layer with different thicknesses on the substrate and filling a specific material in the trench of each photoresist layer, the excess material is removed by a planarization process to form a linear pattern. This method reduces the effect of standing wave effect on the roughness of the photoresist layer by repeatedly filling and removing the photoresist layer material.
A linear pattern with a smaller roughness is achieved in a semiconductor device, which reduces the roughness problem of the photoresist layer and improves the contour quality of the linear pattern.
Smart Images
Figure CN119852164A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for forming a linear pattern in a semiconductor device. Background Art
[0002] The photolithography process is one of the basic steps in the semiconductor device process. In the photolithography process, a photoresist layer with a specific pattern is formed on a layer. Subsequently, the pattern of the photoresist layer is filled with a specific material, and then the photoresist layer is removed to form a patterned layer on the layer below. The photoresist layer may be affected by the standing wave effect, which causes line edge roughness (LER) or line width roughness (LWR) problems of the patterned layer to be formed. The standing wave effect is caused by the formation of standing waves in the photoresist layer, which is caused by the interference between the incident light of the photoresist layer and the light reflected by the layer below the photoresist layer. The standing waves formed in the photoresist layer cause the photoresist layer to have periodically arranged underexposed parts and overexposed parts, and cause the jagged sidewalls of the photoresist layer to travel. Therefore, the standing wave effect will cause the roughness problem of the photoresist layer.
[0003] Typically, the standing wave effect can be reduced by providing a hard mask layer below the photoresist layer. The n / k ratio (ratio of refractive index to extinction coefficient) of the hard mask layer is adjusted to reduce the light reflected by the layer below the photoresist layer, thereby reducing the standing wave effect in the photoresist layer. Another method to reduce the standing wave effect is post exposure bake (PEB). The heat provided by PEB rearranges the photoacid molecules in the underexposed and overexposed portions of the photoresist layer to reduce the jagged sidewalls of the photoresist layer. The heat also drives the deprotection reaction in the photoresist layer and promotes the diffusion of the photoacid molecules in the photoresist layer. However, not all layers are suitable for forming a hard mask layer thereon, and PEB cannot significantly reduce the standing wave effect. Summary of the invention
[0004] Some embodiments of the present disclosure provide a method for forming a linear pattern in a semiconductor device, comprising: forming a first photoresist layer having a first groove above a substrate; filling a first material in the first groove; forming a second photoresist layer having a second groove above the first photoresist layer; filling a second material in the second groove; and after filling the second material in the second groove, removing the first photoresist layer and the second photoresist layer.
[0005] In some embodiments, the second trench is aligned with the first trench.
[0006] In some embodiments, the second material is the same as the first material.
[0007] In some embodiments, the second material is different from the first material.
[0008] In some embodiments, after the first material is filled in the first trench, a top surface of the first material is flush with a top surface of the first photoresist layer.
[0009] In some embodiments, filling the first trench with the first material includes: forming the first material to overfill the first trench, and removing excess portions of the first material by performing a planarization process until a top surface of the first photoresist layer is exposed.
[0010] In some embodiments, after the second material is filled into the second trench, a top surface of the first material is flush with a top surface of the second photoresist layer.
[0011] In some embodiments, filling the second trench with the second material includes: forming the second material to overfill the second trench, and removing excess portions of the second material by performing a planarization process until a top surface of the second photoresist layer is exposed.
[0012] In some embodiments, the first photoresist layer and the second photoresist layer are removed by a single removal process.
[0013] In some embodiments, forming a first photoresist layer having a first trench includes patterning the first photoresist layer, and forming a second photoresist layer having a second trench includes patterning the second photoresist layer, and wherein patterning the first photoresist layer and patterning the second photoresist layer are performed using the same mask.
[0014] Some embodiments of the present disclosure provide a method for forming a linear pattern in a semiconductor device, comprising: forming a first photoresist layer having a first groove above a substrate, wherein the first photoresist layer has a first thickness; filling a first material into the first groove; forming a second photoresist layer having a second groove above the first photoresist layer, the second photoresist layer being in contact with the first photoresist layer, wherein the second photoresist layer has a second thickness; filling a second material into the second groove; and removing the first photoresist layer and the second photoresist layer.
[0015] In some embodiments, opposing sidewalls of the second material are aligned with opposing sidewalls of the first material.
[0016] In some embodiments, the first photoresist layer and the second photoresist layer are made of the same material, and the first thickness is substantially the same as the second thickness.
[0017] In some embodiments, after the first material is filled in the first trench, the first material and the first photoresist layer have substantially the same height.
[0018] In some embodiments, filling the first trench with the first material includes: forming the first material to overfill the first trench, and removing excess portions of the first material by performing a planarization process until a top surface of the first photoresist layer is exposed.
[0019] In some embodiments, after the second material is filled in the second trench, the second material and the second photoresist layer have substantially the same height.
[0020] In some embodiments, filling the second trench with the second material includes: forming the second material to overfill the second trench, and removing excess portions of the second material by performing a planarization process until a top surface of the second photoresist layer is exposed.
[0021] In some embodiments, the first material is filled into the first trench of the first photoresist layer by a first selective epitaxial growth process, and the second material is filled into the second trench of the second photoresist layer by a second selective epitaxial growth process.
[0022] In some embodiments, the first material and the second material are made of semiconductor materials.
[0023] In some embodiments, the substrate is made of a semiconductor material.
[0024] It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The present disclosure may be more fully understood by reading the following detailed description of the embodiments with reference to the accompanying drawings, which are as follows:
[0026] Figures 1 to 7 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some embodiments of the present disclosure.
[0027] Figures 8 to 10 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some other embodiments of the present disclosure.
[0028] Figures 11 to 14 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some other embodiments of the present disclosure.
[0029] Figures 15 to 19 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some other embodiments of the present disclosure. DETAILED DESCRIPTION
[0030] Some embodiments of the present disclosure are used to form linear patterns with less roughness problems. Linear patterns can be used as wires. In addition, intersecting linear patterns can be used to define holes. Linear patterns can be formed by filling a specific material in a groove in a photoresist layer. Photoresist layers with different thicknesses may cause different degrees of standing wave effects. For example, thicker photoresist layers cause a greater degree of standing wave effects, and thinner photoresist layers cause a smaller degree of standing wave effects. A greater degree of standing wave effects may lead to greater roughness of the photoresist layer, such as causing footing or undercut. Therefore, the present disclosure forms a linear pattern by repeatedly filling a specific material in a groove in a photoresist layer (one photoresist layer is located above another photoresist layer) instead of filling a specific material in a groove in a single photoresist layer. The photoresist layer is thin enough, so the photoresist layer is not greatly affected by the standing wave effect. In this way, a linear pattern with less roughness problems can be formed.
[0031] Figures 1 to 7 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some embodiments of the present disclosure. Figure 1 , a first photoresist layer 110 having a first trench T1 is formed on the substrate 100. Specifically, the first photoresist layer 110 having the first trench T1 is formed on the substrate 100 by performing a first patterning process, wherein the first photoresist layer 110 has a first thickness L1. The first thickness L1 is selected so that the first photoresist layer 110 is thin enough and the standing wave effect does not affect the first photoresist layer 110 or cause the roughness of the first photoresist layer 110. In some embodiments, the first thickness L1 is in the range of 30 nm to 50 nm. After the first photoresist layer 110 is formed, the first trench T1 exposes the substrate 100. In some embodiments, the substrate 100 may be any layer in a semiconductor device on which a linear pattern is to be formed, such as a hard mask, a bottom layer, a bottom anti-reflective coating (BARC), or a dielectric antireflective coating (DARC).
[0032] refer to Figure 2 , forming a first material 120 that overfills the first trench T1, and then referring to Figure 3 , the redundant portion of the first material 120 is removed by performing a planarization process until the top surface of the first photoresist layer 110 is exposed. In this way, the first material 120 is filled in the first trench T1. After the first material 120 is filled in the first trench T1, the top surface of the first material 120 is flush with the top surface of the first photoresist layer 110, and the first material 120 and the first photoresist layer 110 have substantially the same height. The first material 120 may be silicon, oxide, or other suitable materials.
[0033] refer to Figure 4 , a second photoresist layer 130 having a second groove T2 is formed on the first photoresist layer 110, and the second photoresist layer 130 contacts the first photoresist layer 110. Specifically, a second photoresist layer 130 having a second groove T2 is formed on the first photoresist layer 110 by performing a second patterning process, wherein the second photoresist layer 130 has a second thickness L2. The second thickness L2 is selected so that the second photoresist layer 130 is thin enough, and the standing wave effect does not affect the second photoresist layer 130 or cause the roughness of the second photoresist layer 130. In some embodiments, the first photoresist layer 110 and the second photoresist layer 130 are made of the same material, and the first thickness L1 (see Figure 1 ) is substantially the same as the second thickness L2, but the present disclosure is not limited thereto. In some embodiments, the first photoresist layer 110 and the second photoresist layer 130 may be patterned using the same mask so that the position and shape of the second trench T2 are the same as the first trench T1 (see FIG. 1 ) of the first photoresist layer 110. Figure 1 ). After forming the second photoresist layer 130 , the second trench T2 is substantially aligned with the first trench T1. In other words, the opposite sidewalls of the second trench T2 may be substantially aligned with the opposite sidewalls of the first material 120 .
[0034] refer to Figure 5 , forming a second material 140 that overfills the second trench T2, and then referring to Figure 6 , the excess portion of the second material 140 is removed by performing a planarization process until the top surface of the second photoresist layer 130 is exposed. In this way, the second material 140 is filled in the second trench T2. After the second material 140 is filled in the second trench T2, the top surface of the second material 140 is flush with the top surface of the second photoresist layer 130, and the second material 140 and the second photoresist layer 130 have substantially the same height. The opposite sidewalls of the second material 140 may be substantially aligned with the opposite sidewalls of the first material 120. In some embodiments, the second material 140 is the same as the first material 120.
[0035] refer to Figure 7, after the second material 140 is filled in the second trench T2, the first photoresist layer 110 and the second photoresist layer 130 are removed. In some embodiments, the first photoresist layer 110 and the second photoresist layer 130 are removed by an etching process. In some other embodiments, the first photoresist layer 110 and the second photoresist layer 130 are removed by an ashing process or stripping. In some embodiments where the first photoresist layer 110 and the second photoresist layer 130 are made of the same material, the first photoresist layer 110 and the second photoresist layer 130 can be removed together in a single removal process as discussed above. In this way, the first material 120 and the second material 140 remain on the substrate 100 and form a linear pattern. Since the first photoresist layer 110 and the second photoresist layer 130 are thin enough and do not cause a serious standing wave effect, the roughness of the first photoresist layer 110 and the second photoresist layer 130 is reduced. The linear pattern formed in the first photoresist layer 110 and the second photoresist layer 130 (i.e., the first material 120 and the second material 140) has less roughness problem. Therefore, when the thickness of the linear pattern in the following two cases is the same, the linear pattern formed in the present disclosure has a better profile than the linear pattern formed in a single photoresist layer.
[0036] Figures 8 to 10 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some other embodiments of the present disclosure. Figures 8 to 10 The formation method of the midline pattern is similar to Figures 1 to 7 In the method for forming a linear pattern. Figure 4 After the process in is completed, execute Figures 8 to 10 The process rather than Figures 5 to 7 The process in.
[0037] refer to Figure 8 ,exist Figure 4 After the process in, a second material 145 is formed to overfill the second trench T2, and then Fig. 9 , the excess portion of the second material 145 is removed by performing a planarization process until the top surface of the second photoresist layer 130 is exposed. In this way, the second material 145 is filled in the second trench T2. After the second material 145 is filled in the second trench T2, the top surface of the second material 145 is flush with the top surface of the second photoresist layer 130. In some embodiments, the second material 145 may be different from the first material 120.
[0038] refer to Fig.10, after the second material 145 is filled in the second trench T2, the first photoresist layer 110 and the second photoresist layer 130 are removed. In some embodiments, the first photoresist layer 110 and the second photoresist layer 130 are removed by an etching process. As a result, the first material 120 and the second material 145 remain on the substrate 100 and form a linear pattern. Since the first photoresist layer 110 and the second photoresist layer 130 are thin enough and do not cause a serious standing wave effect, the roughness of the first photoresist layer 110 and the second photoresist layer 130 is reduced. The linear pattern formed in the first photoresist layer 110 and the second photoresist layer 130 (i.e., the first material 120 and the second material 145) has a smaller roughness problem. Therefore, when the thickness of the linear pattern in the following two cases is the same, the linear pattern formed in the present disclosure has a better profile than the linear pattern formed in a single photoresist layer.
[0039] Figures 11 to 14 A cross-sectional view showing a method of forming a linear pattern in a semiconductor device according to some other embodiments of the present disclosure. Figures 11 to 14 The formation method of the midline pattern is similar to Figures 1 to 7 In the method for forming a linear pattern. Figure 7 After the process in is completed, continue Figures 1 to 14 The process in.
[0040] refer to Fig.11 , a third photoresist layer 150 having a third groove T3 is formed on the second photoresist layer 130, and the third photoresist layer 150 contacts the second photoresist layer 130. Specifically, a third photoresist layer 150 having a third groove T3 is formed on the second photoresist layer 130 by performing a third patterning process, wherein the third photoresist layer 150 has a third thickness L3. The third thickness L3 is selected so that the second photoresist layer 130 is thin enough, and the standing wave effect does not affect the third photoresist layer 150 or cause the roughness of the third photoresist layer 150. In some embodiments, the first photoresist layer 110, the second photoresist layer 130, and the third photoresist layer 150 are made of the same material, and the third thickness L3 is the same as the first thickness L1 (see Figure 1 ) and the second thickness L2 (see Figure 4 ) are substantially the same, but the present disclosure is not limited thereto. After forming the third photoresist layer 150, the third trench T3 is substantially aligned with the second trench T2. In other words, the opposite sidewalls of the third trench T3 may be substantially aligned with the opposite sidewalls of the second material 140.
[0041] refer to Fig.12 , forming a third material 160 that overfills the third trench T3, and then referring to Fig.13, the excess portion of the third material 160 is removed by performing a planarization process until the top surface of the third photoresist layer 150 is exposed. As a result, the third material 160 is filled in the third trench T3. After the third material 160 is filled in the third trench T3, the top surface of the third material 160 is flush with the top surface of the third photoresist layer 150, and the opposite sidewalls of the third material 160 may be substantially aligned with the opposite sidewalls of the second material 140. In some embodiments, the third material 160 may be the same as the second material 140.
[0042] refer to Fig.14 , after the third material 160 is filled in the third trench T3, the first photoresist layer 110, the second photoresist layer 130, and the third photoresist layer 150 are removed. In some embodiments, the first photoresist layer 110, the second photoresist layer 130, and the third photoresist layer 150 are removed by an etching process. In some other embodiments, the first photoresist layer 110, the second photoresist layer 130, and the third photoresist layer 150 are removed using an ashing process or stripping. In some embodiments where the first photoresist layer 110, the second photoresist layer 130, and the third photoresist layer 150 are made of the same material, the first photoresist layer 110, the second photoresist layer 130, and the third photoresist layer 150 may be removed together in a single removal process as discussed above. As a result, the first material 120, the second material 140, and the third material 160 remain over the substrate 100 and form a linear pattern. Since the first photoresist layer 110, the second photoresist layer 130 and the third photoresist layer 150 are thin enough and will not cause a serious standing wave effect, the roughness of the first photoresist layer 110, the second photoresist layer 130 and the third photoresist layer 150 is reduced. The linear pattern (i.e., the first material 120, the second material 140 and the third material 160) formed in the first photoresist layer 110, the second photoresist layer 130 and the third photoresist layer 150 has a smaller roughness problem. Therefore, when the thickness of the linear pattern in the following cases is the same, the linear pattern formed in the present disclosure has a better profile than the linear pattern formed in a single photoresist layer.
[0043] It should be noted that although the second material 140 and the third material 160 are the same as the first material 120 in this embodiment, the present disclosure is not limited thereto. For example, in some embodiments, the first material 120, the second material 140, and the third material 160 are different from each other. In some other embodiments, the first material 120 is the same as the second material 140, and the third material 160 is different from the second material 140. In some other embodiments, the first material 120 is the same as the third material 160, and the second material 140 is different from the third material 160. In some other embodiments, the second material 140 is the same as the third material 160, and the first material 120 is different from the second material 140.
[0044] It should also be noted that the number of photoresist layers used to form the linear pattern is not limited to Figures 1 to 10 2 or as shown Figures 11 to 14 3 as shown. In some embodiments, the number of photoresist layers used to form the linear pattern may be greater than 3. In some embodiments, the number of photoresist layers used to form the linear pattern may be determined by the total thickness of the linear pattern. For example, the greater the total thickness of the linear pattern, the more photoresist layers are formed to form the linear pattern. Therefore, even if the total thickness of the linear pattern is large, such as 1000nm to 10000nm, the formed linear pattern has a smaller roughness problem.
[0045] Figures 15 to 19 A cross-sectional view showing a linear pattern formed in a semiconductor device in some other embodiments of the present disclosure. Specifically, the linear pattern may be formed by selective epitaxial growth. Figures 15 to 19 Linear pattern in .
[0046] refer to Fig.15 , a first photoresist layer 110 having a first trench T1 is formed on the substrate 100 . Fig.15 The first photoresist layer 110 in the embodiment may be similar to Figure 1 The first photoresist layer 110 described in Fig.15 In the embodiment, the substrate 100 is a semiconductor layer, such as a silicon layer.
[0047] refer to Fig.16 , the first material 120 is filled in the first trench T1 of the first photoresist layer 110. Specifically, the first material 120 can be filled in the first trench T1 of the first photoresist layer 110 by a selective epitaxial growth process. The first material 120 can be a semiconductor material, such as silicon, that is selectively grown on the substrate 100. During the selective epitaxial growth of the first material 120 on the substrate 100, the silicon of the first material 120 grows only on the exposed surface of the substrate 100 made of silicon, and does not grow on the first photoresist layer 110. Therefore, the first material 120 is formed in the first trench T1 of the first photoresist layer 110.
[0048] refer to Fig.17 , a second photoresist layer 130 having a second trench T2 is formed on the first photoresist layer 110 . Fig.17 The second photoresist layer 130 in Figure 4 The second photoresist layer 130 described in .
[0049] refer to Fig.18, the second material 140 is filled in the second trench T2 of the second photoresist layer 130. Specifically, the second material 140 can be filled in the second trench T2 of the second photoresist layer 130 by a selective epitaxial growth process. The second material 140 can be a semiconductor material, such as silicon, that is selectively grown on the first material 120. During the selective epitaxial growth of the second material 140 on the first material 120, the silicon of the second material 140 grows only on the exposed surface of the first material 120 made of silicon, and does not grow on the second photoresist layer 130. Therefore, the second material 140 is formed in the second trench T2 of the second photoresist layer 130.
[0050] refer to Fig.19 , remove the first photoresist layer 110 and the second photoresist layer 130 . Fig.19 The removal process of the first photoresist layer 110 and the second photoresist layer 130 is similar to Figure 7 The removal process described in .
[0051] As described above, a linear pattern is formed by repeatedly filling a specific material into the grooves in the photoresist layer. The photoresist layer is thin enough so that the photoresist layer is not greatly affected by the standing wave effect. In order to form a linear pattern with a large thickness and a small roughness at the same time, the number of photoresist layers used to form the linear pattern can be determined by the total thickness of the linear pattern. The materials filled in each photoresist layer may be the same or different from each other. Therefore, the linear pattern can be made of a single material or multiple materials.
[0052] Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
[0053] Those skilled in the art will appreciate that various modifications and variations may be made to the structure of the present disclosure without departing from the scope or spirit of the present disclosure. In view of the foregoing, the present disclosure is intended to cover modifications and variations of the present disclosure that fall within the scope of the following claims.
[0054]
Explanation of symbols
[0055] 100:Substrate
[0056] 110: first photoresist layer
[0057] 120:First Material
[0058] 130: second photoresist layer
[0059] 140: Second Material
[0060] 145: Second Material
[0061] 150: third photoresist layer
[0062] 160: Third Material
[0063] T1: First groove
[0064] T2: Second groove
[0065] T3: The third groove.
Claims
1. A method for forming a linear pattern in a semiconductor device, characterized in that: Include: forming a first photoresist layer having a first groove over the substrate; Filling the first trench with a first material; forming a second photoresist layer having a second groove on the first photoresist layer; Filling the second trench with a second material; and After the second material is filled in the second trench, the first photoresist layer and the second photoresist layer are removed.
2. The method according to claim 1, characterized in that The second groove is aligned with the first groove.
3. The method according to claim 1, characterized in that The second material is the same as the first material.
4. The method according to claim 1, characterized in that: The second material is different from the first material.
5. The method according to claim 1, characterized in that: After the first material is filled in the first trench, the top surface of the first material is flush with the top surface of the first photoresist layer.
6. The method according to claim 5, characterized in that The step of filling the first material in the first trench comprises: forming the first material to overfill the first trench; and The redundant portion of the first material is removed by performing a planarization process until the top surface of the first photoresist layer is exposed.
7. The method according to claim 1, characterized in that After the second material is filled in the second trench, the top surface of the second material is flush with the top surface of the second photoresist layer.
8. The method according to claim 7, characterized in that The step of filling the second material into the second trench comprises the following steps: forming the second material to overfill the second trench; and The redundant portion of the second material is removed by performing a planarization process until the top surface of the second photoresist layer is exposed.
9. The method according to claim 1, characterized in that: The first photoresist layer and the second photoresist layer are removed through a single removal process.
10. The method according to claim 1, characterized in that The step of forming the first photoresist layer with the first groove includes patterning the first photoresist layer, and forming the second photoresist layer with the second groove includes patterning the second photoresist layer, and patterning the first photoresist layer and patterning the second photoresist layer are performed using the same mask.
11. A method for forming a linear pattern in a semiconductor device, characterized in that: It contains the following steps: Forming a first photoresist layer having a first groove on the substrate, wherein the first photoresist layer has a first thickness; Filling the first trench with a first material; Forming a second photoresist layer having a second groove above the first photoresist layer, the second photoresist layer is in contact with the first photoresist layer, wherein the second photoresist layer has a second thickness; Filling the second trench with a second material; and The first photoresist layer and the second photoresist layer are removed.
12. The method according to claim 11, characterized in that Wherein opposing side walls of the second material are aligned with opposing side walls of the first material.
13. The method according to claim 11, characterized in that The first photoresist layer and the second photoresist layer are made of the same material, and the first thickness is substantially the same as the second thickness.
14. The method according to claim 11, characterized in that After the first material is filled in the first trench, the first material and the first photoresist layer have substantially the same height.
15. The method according to claim 14, characterized in that The step of filling the first material in the first trench comprises: forming the first material to overfill the first trench; and The redundant portion of the first material is removed by performing a planarization process until the top surface of the first photoresist layer is exposed.
16. The method according to claim 11, characterized in that After the second material is filled in the second trench, the second material and the second photoresist layer have substantially the same height.
17. The method according to claim 16, characterized in that The step of filling the second material in the second trench comprises: forming the second material to overfill the second trench; and The redundant portion of the second material is removed by performing a planarization process until the top surface of the second photoresist layer is exposed.
18. The method according to claim 11, characterized in that The first material is filled into the first groove of the first photoresist layer through a first selective epitaxial growth process, and the second material is filled into the second groove of the second photoresist layer through a second selective epitaxial growth process.
19. The method according to claim 18, characterized in that The first material and the second material are made of semiconductor materials.
20. The method according to claim 18, characterized in that The substrate is made of semiconductor material.