Method of manufacturing a multi-depth waveguide structure and multi-depth waveguide structure
Patent Information
- Application Number
- CN202510547222.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-28
- Publication Date
- 2026-10-30
AI Technical Summary
针对该问题目前采用的方法是加厚的堆叠结构的各膜层，但是过厚会导致刻蚀负载效应，影响硅波导的倾角，同时导致各膜层因厚度增加而偏离光学反射率仿真最佳值，会造成光刻胶驻波效应
[0022]综上所述，本发明提供的多深度波导结构的制造方法及多深度波导结构包括：提供具有沟槽的衬底；利用填充层填充所述沟槽，所述填充层的上表面与所述衬底的上表面持平；在所述填充层和所述衬底的表面形成多层掩膜堆叠结构，所述多层掩膜堆叠结构各膜层的厚度值与所采用的光刻工艺的光学反射率仿真最佳值相匹配；图形化所述多层掩膜堆叠结构，并以图形化的所述多层掩膜堆叠结构为掩膜对所述衬底进行刻蚀，以将目标图案转移至所述衬底；以及，去除剩余的所述多层掩膜堆叠结构和所述填充层。本发明提供的所述制造方法，使用填充层对刻蚀后的沟槽填充，可在形成多层掩膜堆叠结构之前，达到平坦化的目的，如此，可以避免多层掩膜堆叠结构不同区域出现厚度差而造成下层衬底刻蚀损伤，因此也无需加厚多层掩膜堆叠结构的各膜层来避免下层衬底刻蚀损伤，多层掩膜堆叠结构的各膜层可以维持在光学反射率仿真最佳值，另外，也可以避免因多层掩膜堆叠结构的各膜层过厚而导致的刻蚀负载效应产生，同时也节省材料，降低生产成本。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method for manufacturing a multi-depth waveguide structure and the multi-depth waveguide structure itself. Background Technology
[0002] Multi-depth silicon waveguides are an important component of silicon photonics technology. They involve forming waveguide structures with specific optical properties on silicon substrates through multi-layer etching processes at different depths. However, realizing multi-depth silicon waveguides is one of the current challenges in patterning processes, especially full etching patterning in silicon waveguides, which requires deep etching patterning as a foundation. Therefore, planarization of the preceding layers in this process is a significant challenge.
[0003] In deep etching patterning, multi-layer mask stacks are often used for image transfer. However, in actual development, using multi-layer mask stacks of conventional thickness reveals patterning weaknesses in some isolated deep etching areas. In these areas, the layers of the stacked structure are thinner than in the planar areas. During subsequent full etching, these layers are consumed before the planar areas, damaging the underlying silicon substrate. Current solutions address this by thickening the layers of the stacked structure. However, excessive thickness leads to etching load effects, affecting the tilt angle of the silicon waveguide. Furthermore, the increased thickness causes each layer to deviate from its simulated optimal optical reflectivity, resulting in photoresist standing wave effects. On the other hand, unevenness in the preceding layers can cause defocusing during photolithography, thus affecting the resolution of the process. Summary of the Invention
[0004] The purpose of this invention is to provide a method for manufacturing a multi-depth waveguide structure and the multi-depth waveguide structure itself, so as to solve one or more problems in the prior art.
[0005] To solve the above-mentioned technical problems, the present invention provides a method for manufacturing a multi-depth waveguide structure, comprising:
[0006] Provide a substrate with trenches;
[0007] The trench is filled with a filling layer, the upper surface of which is flush with the upper surface of the substrate;
[0008] A multilayer mask stack structure is formed on the surface of the filling layer and the substrate, and the thickness value of each layer of the multilayer mask stack structure is matched with the optimal value of optical reflectivity simulation of the photolithography process used.
[0009] The multilayer mask stack structure is patterned, and the substrate is etched using the patterned multilayer mask stack structure as a mask to transfer the target pattern to the substrate; and,
[0010] Remove the remaining multilayer mask stack structure and the filler layer.
[0011] Optionally, in the method for manufacturing the multi-depth waveguide structure, the step of forming the filling layer includes:
[0012] The trench is overfilled with the filler layer such that the upper surface of the filler layer is higher than the upper surface of the substrate; and,
[0013] The filler layer is planarized so that the upper surface of the filler layer is flush with the upper surface of the substrate.
[0014] Optionally, in the manufacturing method of the multi-depth waveguide structure, the process of planarizing the filling layer includes: an etching planarization process.
[0015] Optionally, in the method for manufacturing the multi-depth waveguide structure, the filling layer includes a bottom anti-reflective coating.
[0016] Optionally, in the method for manufacturing the multi-depth waveguide structure, the multilayer mask stack structure includes a bottom layer, an intermediate layer, and a top layer stacked sequentially from bottom to top. The bottom layer serves as a planarization layer and an etching barrier layer, the intermediate layer is an anti-reflection layer, and the top layer is a photoresist layer.
[0017] Optionally, in the method for manufacturing the multi-depth waveguide structure, the intermediate layer includes a silicon-containing anti-reflection coating.
[0018] Optionally, in the manufacturing method of the multi-depth waveguide structure, the bottom layer includes a spin-coated carbon layer.
[0019] Optionally, in the method for manufacturing the multi-depth waveguide structure, the substrate is a silicon substrate.
[0020] Optionally, in the manufacturing method of the multi-depth waveguide structure, the optimal value of the simulated optical reflectivity is obtained based on the lithography performance of the lithography machine used and the material properties of the corresponding film layers of the multilayer mask stack structure.
[0021] The present invention also provides a multi-depth waveguide structure, which is manufactured using the manufacturing method described in any of the preceding claims.
[0022] In summary, the manufacturing method and the multi-depth waveguide structure provided by the present invention include: providing a substrate with trenches; filling the trenches with a filling layer, the upper surface of the filling layer being flush with the upper surface of the substrate; forming a multilayer mask stack structure on the surfaces of the filling layer and the substrate, wherein the thickness value of each layer of the multilayer mask stack structure matches the optimal value of the optical reflectivity simulation of the photolithography process used; patterning the multilayer mask stack structure, and using the patterned multilayer mask stack structure as a mask to etch the substrate to transfer the target pattern to the substrate; and removing the remaining multilayer mask stack structure and the filling layer. The manufacturing method provided by this invention uses a filling layer to fill the etched trenches, which can achieve planarization before forming a multilayer mask stack structure. This avoids thickness differences in different areas of the multilayer mask stack structure that could cause etching damage to the underlying substrate. Therefore, it is not necessary to thicken the layers of the multilayer mask stack structure to avoid etching damage to the underlying substrate. The layers of the multilayer mask stack structure can be maintained at the optimal value of optical reflectivity simulation. In addition, it can also avoid the etching load effect caused by excessive thickness of the layers of the multilayer mask stack structure, while also saving materials and reducing production costs. Attached Figure Description
[0023] Figure 1 A flowchart illustrating the manufacturing method of a multi-depth waveguide structure provided in an embodiment of the present invention;
[0024] Figures 2-5 for Figure 1 Schematic diagram of the device structure corresponding to steps S1 to S3;
[0025] The labels in the accompanying drawings are explained as follows:
[0026] 11-Substrate; 12-Fill layer; 13-Bottom layer; 14-Intermediate layer; 15-Top layer. Detailed Implementation
[0027] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different proportions are sometimes used in the drawings to show different emphases. It should be understood that relative terms such as "above," "below," "top," and "bottom" shown in the drawings can be used to describe the relationships between various elements. These relative terms are intended to cover different orientations of elements other than those depicted in the drawings. For example, if the device is inverted relative to the view in the drawings, an element described, for example, as being "above" another element would now be below that element.
[0028] Figure 1 A flowchart of the manufacturing method of the multi-depth waveguide structure provided in the embodiments of the present invention is shown below. Figure 1 As shown, the manufacturing method provided in this embodiment of the invention includes the following steps:
[0029] S1 provides a substrate with trenches;
[0030] S2, the trench is filled with a filling layer, the upper surface of which is flush with the upper surface of the substrate;
[0031] S3, a multilayer mask stack structure is formed on the surface of the filling layer and the substrate, wherein the thickness value of each layer of the multilayer mask stack structure matches the optimal value of the optical reflectivity simulation of the photolithography process used;
[0032] S4, pattern the multilayer mask stack structure, and use the patterned multilayer mask stack structure as a mask to etch the substrate to transfer the target pattern to the substrate;
[0033] S5, remove the remaining multilayer mask stack structure and the fill layer.
[0034] The manufacturing method provided in this embodiment of the invention uses a filling layer to fill the etched trenches, which can achieve planarization before forming a multilayer mask stack structure. This avoids thickness differences in different areas of the multilayer mask stack structure that could cause etching damage to the underlying substrate. Therefore, it is not necessary to thicken the layers of the multilayer mask stack structure to avoid etching damage to the underlying substrate. The layers of the multilayer mask stack structure can be maintained at the optimal value of optical reflectivity simulation. In addition, it can also avoid the etching load effect caused by excessive thickness of the layers of the multilayer mask stack structure, while also saving materials and reducing production costs.
[0035] The following combination Figures 2-5The steps of the manufacturing method provided in this embodiment will be described in further detail.
[0036] First, perform step S1, please refer to [link / reference]. Figure 2 A substrate 11 with trenches is provided.
[0037] The substrate 11 can be made of a suitable material according to the application requirements. In this embodiment, the substrate 11 can be a silicon substrate. In other embodiments, the material of the substrate 11 can also be silicon nitride, gallium arsenide, silicon carbide, etc.
[0038] Next, perform step S2, please refer to [link / reference]. Figure 4 The trench is filled with a filling layer 12, the upper surface of which is flush with the upper surface of the substrate 11.
[0039] The steps for forming the filling layer 12 may specifically include: such as Figure 3 As shown, the filler layer 12 is overfilled in the trench such that the upper surface of the filler layer 12 is higher than the upper surface of the substrate 11; and, as Figure 4 As shown, the filler layer 12 is planarized so that the upper surface of the filler layer 12 is flush with the upper surface of the substrate 11.
[0040] Optionally, the filler layer 12 can be planarized using an etching planarization process. Specifically, dry or wet etching techniques can be used to remove surface high points to achieve planarization. In other embodiments, other suitable planarization processes can also be used to planarize the filler layer 12, such as chemical mechanical planarization.
[0041] In this embodiment, preferably, the filling layer 12 is a bottom anti-reflective coating (BARC). The removal method for the bottom anti-reflective coating is simple and has low process risk; it can be removed using oxygen plasma ashing or wet cleaning (such as a mixture of sulfuric acid and hydrogen peroxide). Furthermore, the bottom anti-reflective coating, combined with the intermediate layer of the multilayer mask stack structure described below, provides a dual anti-reflective effect. This not only solves the defocusing problem caused by unevenness in the preceding layer during photolithography, but also further optimizes the anti-reflective effect and reduces standing wave effects.
[0042] In other embodiments, suitable alternatives or combinations can be selected based on specific process requirements (such as aspect ratio, material compatibility, thermal stability, etc.). For example, for trenches with higher aspect ratios, spin-coated glass (SOG) can also be used for filling.
[0043] Next, proceed to step S3, please refer to [link / reference]. Figure 5A multilayer mask stack structure is formed on the surfaces of the filler layer 12 and the substrate 11. The multilayer mask stack structure works together to transfer the target pattern to the substrate 11.
[0044] As mentioned earlier, in the prior art, to avoid etching damage to the underlying substrate caused by thickness differences in different regions of the multilayer mask stack structure, the thickness of each film layer is increased. However, this also leads to etching load effects and standing wave effects. In this embodiment, since the trenches of the substrate 11 are filled before forming the multilayer mask stack structure, no thickness difference will form in different regions after the multilayer mask stack structure is formed. Naturally, there is no need to increase the thickness of each film layer to avoid substrate etching damage. Each film layer of the multilayer mask stack structure can maintain the optimal value of optical reflectivity simulation, and there will be no etching load effect or standing wave effect.
[0045] In this embodiment, the multilayer mask stack structure specifically includes a bottom layer 13, an intermediate layer 14, and a top layer 15 stacked sequentially from bottom to top. The bottom layer 13 serves as a planarization layer and an etching barrier layer. Specifically, the bottom layer 13 provides a flat substrate for subsequent coatings, preventing exposure distortion of the photoresist (PR) due to surface unevenness. Additionally, the bottom layer 13 also acts as an etching barrier layer; when etching the upper layer material, the bottom layer 13 acts as a stop layer, ensuring that etching stops after a certain point, protecting the lower layer structure. The intermediate layer 14 is an anti-reflection layer, used to reduce reflectivity, optimize the exposure energy distribution of the photoresist, and improve the resolution and edge steepness of the developed pattern. The top layer 15 is a photoresist layer, which forms the target pattern through exposure and development, serving as a mask for subsequent etching.
[0046] To ensure accurate downward transfer of the pattern, in this embodiment, optionally, the intermediate layer 14 uses a silicon-based anti-reflective coating (Si-ARC), and the bottom layer 13 uses a spin-coated carbon layer (SOC). The spin-coated carbon layer has a high etch selectivity for silicon and can play a better role in etch blocking.
[0047] In other embodiments, the bottom layer 13 may also be an organic planarization layer (OPL), or a combination of the spin-coated carbon layer and the organic planarization layer, etc. The intermediate layer 14 may also be an organic antireflective coating (OBARC), or a combination of the silicon-containing antireflective coating and the organic antireflective coating, etc. The materials of the bottom layer 13 and the intermediate layer 14 can be matched according to actual process requirements.
[0048] Next, step S4 is performed to pattern the multilayer mask stack structure and etch the substrate 11 with the patterned multilayer mask stack structure to transfer the target pattern to the substrate 11.
[0049] As an example, the process of pattern transfer using a photoresist layer, a silicon-containing anti-reflective coating, and a spin-coated carbon layer is as follows:
[0050] After exposure and development, the photoresist forms a pattern → the pattern is transferred to the silicon-containing anti-reflective coating by dry etching (using plasma such as CF4 / CHF3) → the spin-coated carbon layer receives the pattern by O2 or SO2 plasma etching → using the spin-coated carbon layer pattern as a mask, the pattern is finally transferred to the substrate 11 by dry etching (using etching gases such as Cl2, HBr).
[0051] Finally, step S5 is performed to remove the remaining multilayer mask stack structure and the fill layer 12.
[0052] As an example, the silicon-containing antireflective coating can be removed by dry etching, specifically by plasma etching with fluorine-containing gases (such as CF4, CHF3, SF6); the spin-coated carbon layer can be removed by dry etching, specifically by plasma etching with oxygen (O2) or oxygen-containing gases (such as O2 / Ar, O2 / N2); and the bottom antireflective layer can be removed using a special etching solution (such as TMAH or a sulfuric acid / hydrogen peroxide mixture).
[0053] This embodiment also provides a multi-depth waveguide structure, which is manufactured using the manufacturing method described in this embodiment. Since some problems such as substrate etching damage, etching load effect and standing wave effect during the etching process to form trenches are solved, the performance of the multi-depth waveguide structure provided in this embodiment is improved.
[0054] In summary, the manufacturing method and multi-depth waveguide structure provided by the embodiments of the present invention include: providing a substrate with trenches; filling the trenches with a filling layer, the upper surface of the filling layer being flush with the upper surface of the substrate; forming a multilayer mask stack structure on the surfaces of the filling layer and the substrate, wherein the thickness value of each layer of the multilayer mask stack structure matches the optimal value of optical reflectivity simulation of the photolithography process used; patterning the multilayer mask stack structure, and using the patterned multilayer mask stack structure as a mask to etch the substrate to transfer the target pattern to the substrate; and removing the remaining multilayer mask stack structure and the filling layer. The manufacturing method provided in this embodiment of the invention uses a filling layer to fill the etched trenches, which can achieve planarization before forming a multilayer mask stack structure. This avoids thickness differences in different areas of the multilayer mask stack structure that could cause etching damage to the underlying substrate. Therefore, it is not necessary to thicken the layers of the multilayer mask stack structure to avoid etching damage to the underlying substrate. The layers of the multilayer mask stack structure can be maintained at the optimal value of optical reflectivity simulation. In addition, it can also avoid the etching load effect caused by excessive thickness of the layers of the multilayer mask stack structure, while also saving materials and reducing production costs.
[0055] Furthermore, it should be understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments with equivalent changes, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.
Claims
1. A method for manufacturing a multi-depth waveguide structure, characterized in that, include: Provide a substrate with trenches; The trench is filled with a filling layer, the upper surface of which is flush with the upper surface of the substrate; A multilayer mask stack structure is formed on the surface of the filling layer and the substrate, and the thickness value of each layer of the multilayer mask stack structure is matched with the optimal value of optical reflectivity simulation of the photolithography process used. The multilayer mask stack structure is patterned, and the substrate is etched using the patterned multilayer mask stack structure as a mask to transfer the target pattern to the substrate; as well as, Remove the remaining multilayer mask stack structure and the filler layer.
2. The method for manufacturing a multi-depth waveguide structure as described in claim 1, characterized in that, The steps for forming the filling layer include: The trench is overfilled with the filler layer such that the upper surface of the filler layer is higher than the upper surface of the substrate; and, The filler layer is planarized so that the upper surface of the filler layer is flush with the upper surface of the substrate.
3. The method for manufacturing a multi-depth waveguide structure as described in claim 2, characterized in that, The process for planarizing the filling layer includes: an etching planarization process.
4. The method for manufacturing a multi-depth waveguide structure as described in claim 1, characterized in that, The filler layer includes a bottom anti-reflective coating.
5. The method for manufacturing a multi-depth waveguide structure as described in claim 1, characterized in that, The multilayer mask stack structure includes a bottom layer, an intermediate layer and a top layer stacked sequentially from bottom to top. The bottom layer serves as a planarization layer and an etching barrier layer, the intermediate layer is an anti-reflection layer, and the top layer is a photoresist layer.
6. The method for manufacturing a multi-depth waveguide structure as described in claim 5, characterized in that, The intermediate layer includes a silicon-containing anti-reflective coating.
7. The method for manufacturing a multi-depth waveguide structure as described in claim 5, characterized in that, The bottom layer includes a spin-coated carbon layer.
8. The method for manufacturing a multi-depth waveguide structure as described in claim 1, characterized in that, The substrate is a silicon substrate.
9. The method for manufacturing a multi-depth waveguide structure as described in claim 1, characterized in that, The optimal value of the optical reflectivity simulation is obtained based on the lithography performance of the lithography machine used and the material properties of the corresponding film layers of the multilayer mask stack structure.
10. A multi-depth waveguide structure, characterized in that, The multi-depth waveguide structure is manufactured using the manufacturing method described in any one of claims 1 to 9.