Patterning method
By removing the partition walls of the axial structure in the DRAM manufacturing process, using the partition walls of the non-axial structure as mask, adjusting the spacing between patterns, the problems of difficulty in adjusting the spacing and complex manufacturing process in the prior art are solved, and the purpose of reducing manufacturing costs and simplifying the process is achieved.
Patent Information
- Application Number
- CN202411717987.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-02-28
AI Technical Summary
In the manufacturing process of dynamic random access memory (DRAM), it is difficult for the prior art to effectively adjust the spacing between patterns, and the manufacturing process is complex, resulting in high manufacturing costs and difficult process simplification.
By removing the mask structure as the axial structure and its partition walls on the top and side walls, the partition walls at the remaining non-axial structures are used as masks for the subsequent patterning process, the spacing between patterns is adjusted using the wider non-axial structure without the need for an additional mask.
The spacing between patterns is adjusted, manufacturing costs are reduced, process processes are simplified, and the integration of DRAM devices is improved.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to a patterning method. Background Art
[0002] Dynamic random access memory (DRAM) is a type of volatile memory that includes an array area consisting of multiple memory cells and a peripheral area where the control circuit is located. The control circuit can locate each memory cell and control the access of its data through word lines and bit lines that span the array area and are electrically connected to each memory cell. In order to improve the integration of dynamic random access memory, while miniaturizing the feature size of the memory cell, an array structure that can be arranged more closely has also been developed. For example, the word lines or bit lines of the memory array are set below the surface of the chip to form buried word lines or buried bit lines. In advanced semiconductor manufacturing, the chip size of DRAM devices can be greatly reduced by adopting the buried word line or buried bit line architecture. Through this architecture, the active area of the memory cell can be arranged at a dense pitch to obtain a higher cell density. However, in order to achieve the above architecture, the manufacturing process of DRAM has become increasingly complex. Summary of the invention
[0003] The purpose of the present invention is to provide a patterning method, by removing the mask structure as the axial structure and the partition walls on the top surface and side walls, so that the remaining partition walls at the non-axial structure can be used as a mask for the subsequent patterning process, and the spacing between patterns can be adjusted without an additional mask.
[0004] In order to solve the above technical problems, the present invention provides a patterning method, which may at least include:
[0005] providing a substrate;
[0006] forming a target layer on the substrate;
[0007] forming a plurality of mask structures spaced apart from each other and located on the target layer;
[0008] forming a spacer wall to cover the mask structure and the target layer;
[0009] forming a first mask layer to cover the spacers and at least fill the gaps between adjacent mask structures;
[0010] removing the mask structure, the first mask layer and a portion of the spacer, and retaining a portion of the spacer;
[0011] The target layer is etched with the remaining partition walls as a mask to form a pattern, wherein the pattern is aligned with the remaining partition walls.
[0012] Optionally, the mask structure may include a second mask layer and an etch stop layer stacked in sequence from bottom to top.
[0013] Optionally, the remaining spacer walls may be located on the bottom surface of the first mask layer between adjacent mask structures and may be in a "one" shape.
[0014] Optionally, the remaining spacer walls may be located on the side walls and the bottom surface of the first mask layer between adjacent mask structures and may be in a "U" shape.
[0015] Optionally, the step of removing the mask structure, the first mask layer, and part of the spacer walls may include:
[0016] Performing an etching process on the spacer walls on the top surfaces of the first mask layer and the mask structure until the etch stop layer in the mask structure is exposed;
[0017] Continuing to perform an etching process on the remaining spacer walls between adjacent mask structures to remove the spacer walls on the side walls of the first mask layer between adjacent mask structures and retaining part of the spacer walls on the bottom surface of the first mask layer between adjacent mask structures;
[0018] Removing the etch stop layer.
[0019] Optionally, the step of removing the mask structure, the first mask layer, and part of the spacer walls may include:
[0020] Performing an etching process on part of the spacer walls on the top surfaces of the first mask layer and the mask structure until the etch stop layer in the mask structure is exposed and retaining part of the spacer walls on the side walls and the bottom surface of the first mask layer between adjacent mask structures;
[0021] Removing the etch stop layer.
[0022] Optionally, after removing the mask structure, the first mask layer, and part of the spacer walls, it may further include:
[0023] Removing the second mask layer in the mask structure and the remaining first mask layer between adjacent mask structures.
[0024] Optionally, the width of the pattern formed with the remaining spacer walls in a "one" shape as a mask in the horizontal direction may be smaller than the width of the pattern formed with the remaining spacer walls in a "U" shape as a mask in the horizontal direction.
[0025] Optionally, the patterning method provided by the present invention may further include:
[0026] An insulating layer is formed to fill the gaps between adjacent patterns.
[0027] Optionally, the first mask layer and the second mask layer may be made of the same material.
[0028] Optionally, the target layer may include a metal material.
[0029] In the present invention, by removing the mask structure serving as the axial structure and the partition walls on its top surface and side walls, the partition walls at the remaining non-axial structure are used as masks for subsequent patterning processes, thereby achieving the purpose of adjusting (increasing) the spacing between adjacent patterns formed in the target layer by utilizing the wider non-axial structure without the need for additional masks, thereby also achieving the purpose of reducing manufacturing costs and simplifying the process. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present application but do not constitute a limitation to the present application. In the accompanying drawings:
[0031] Figure 1 is a flow chart of a patterning method provided in one embodiment of the present invention;
[0032] Figure 2 to Figure 9 It is a schematic structural diagram of a patterning method provided in an embodiment of the present invention during the preparation process.
[0033] Wherein, the accompanying drawings are marked as follows:
[0034] 100-substrate, 110-target layer, 120-mask structure, 121-second mask layer, 122-etching stop layer, 130-spacer, 140-first mask layer, 131-spacer remaining on the sidewall of the first mask layer between adjacent mask structures, 132-spacer remaining on the bottom of the first mask layer between adjacent mask structures, 141-first mask layer remaining between adjacent mask structures, 111-pattern, 150-insulating layer.
[0035] In the drawings, the same reference numerals are used for the same components and the drawings are not drawn to scale. DETAILED DESCRIPTION
[0036] In order to make the technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Although the exemplary implementation methods of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the implementation methods described here. On the contrary, these implementation methods are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0037] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become clearer according to the following description and claims. It should be noted that the accompanying drawings are all in very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. It is understood that the meanings of "on", "above" and "above" in the present invention should be interpreted in the broadest way, so that "on" not only means that it is "on" something and there are no intervening features or layers (i.e. directly on something), but also includes the meaning of being "on" something and having intervening features or layers.
[0038] See also Figure 1 , Figure 1 FIG. 1 is a flow chart of a patterning method provided in an embodiment of the present invention. Figure 1 As shown, the patterning method provided in this embodiment includes at least the following steps:
[0039] Step S101, providing a substrate;
[0040] Step S102, forming a target layer on the substrate;
[0041] Step S103, forming a plurality of mask structures that are separated from each other and are located on the target layer;
[0042] Step S104, forming a spacer to cover the mask structure and the target layer;
[0043] Step S105, forming a first mask layer to cover the spacers and at least fill the gaps between adjacent mask structures;
[0044] Step S106, removing the mask structure, the first mask layer and part of the spacers, and retaining part of the spacers;
[0045] Step S107 , using the remaining partition walls as a mask, etching the target layer to form a pattern, wherein the pattern is aligned with the remaining partition walls.
[0046] In the present invention, after forming a gap between a mask structure as an axial structure and an adjacent mask structure as a non-axial structure on a target layer, partition walls can be formed on the outer surfaces of the axial structure and the non-axial structure, and then the corresponding partition walls on the axial structure and its top surface and side walls are removed, that is, part of the partition walls at the non-axial structure are retained, and then the remaining partition walls at the non-axial structure are used to achieve the purpose of adjusting the spacing between adjacent patterns (alignment mark patterns) subsequently formed in the target layer (the material is a metal material) by utilizing the characteristic that the width is wider along the direction parallel to the substrate surface.
[0047] In order to enable a person skilled in the art to which the present invention belongs to easily understand the patterning method in the embodiment of the present invention, the patterning method proposed in the present invention will be further described below in conjunction with various structural schematic diagrams of the patterning method during the preparation process. Figure 2 to Figure 9 It is a schematic diagram of the structure of the patterning method provided in an embodiment of the present invention during the preparation process.
[0048] Please refer to Figure 2 , perform the above steps S101 to S103: provide a substrate 100, then use at least one of the deposition processes such as physical vapor deposition, chemical vapor deposition, atomic layer deposition, etc. to sequentially form a target layer 110, a second mask layer 121 and an etch stop layer 122 on the surface of the substrate 100 from bottom to top, and then use at least one of the etching processes such as dry etching or wet etching to sequentially etch the etch stop layer 122 and the second mask layer 121 downward in a direction perpendicular to the surface of the substrate 100 (hereinafter referred to as the vertical direction) to divide the second mask layer 121 and the etch stop layer 122 that cover the target layer 110 as a whole into a plurality of mask structures 120 that are separated from each other along a direction parallel to the surface of the substrate 100 (hereinafter referred to as the horizontal direction), and each of the mask structures 120 includes a stacked portion of the second mask layer 121 and the etch stop layer 122 aligned therewith. In one embodiment, the substrate 100 is any suitable substrate material known in the art, such as a silicon substrate, a silicon-containing substrate, a silicon-on-insulator substrate, or a substrate composed of other suitable materials, etc., but not limited thereto. The material of the target layer 110 is a metal material, such as tungsten and its alloys, but not limited thereto. The material of the second mask layer 121 is an organic dielectric material with excellent filling ability, such as silicon oxide, but not limited thereto. The material of the etch stop layer 122 is an insulating material, such as silicon nitride, but not limited thereto. The shape of the mask structure 120 is a strip or a column, but not limited thereto.
[0049] It should be understood that in a patterning process (such as SADP, SARP or SAQP, etc.), the mask structure 120 is usually referred to as an axial structure, and the gap or void between adjacent mask structures 120 can be referred to as a non-axial structure. In addition, since the pattern finally formed in the target layer 110 in the embodiment of the present invention is an alignment mark pattern, the target layer 110 made of a metal material can be a single-layer structure, such as a metal tungsten layer, or a composite layer structure, such as a stacked structure of a metal tungsten layer, a silicon nitride layer and a metal tungsten layer. In order to simplify the drawings, the drawings in the embodiment of the present invention only illustrate the case where the target layer 110 is a single-layer structure, but are not limited thereto.
[0050] Please refer to Figure 3 , perform the above step S104: Then continue to use one of the above deposition processes, such as a chemical vapor deposition process, to form a layer of spacers 130 on the outer surface of the mask structure 120 and on the target layer 110 exposed at the bottom of the gap or void between adjacent mask structures 120, that is, the spacers 130 conformally cover the substrate 100. In one embodiment, the material of the spacers 130 is an oxide, such as silicon dioxide, but is not limited thereto.
[0051] Please refer to Figure 4 , perform the above step S105: Then, at least one of the above deposition processes may be used to form a first mask layer 140 on the substrate 100 to at least fill the spaces or gaps between the adjacent mask structures 120 after the spacers 130 are formed. In one embodiment, the material of the first mask layer 140 is the same as that of the second mask layer 121 in the mask structure 120, for example, both are silicon oxide, an organic dielectric material with excellent filling ability, but not limited to this. The first mask layer 140 not only fills the spaces or gaps between the adjacent mask structures 120, but also extends in the horizontal direction to cover the surface of the spacers 130 on the top surface of the mask structure 120, so as to bury all the film layer structures on the substrate 100.
[0052] Please refer to Figure 5, perform the above step S106: Then, using a grinding process such as chemical mechanical polishing (CMP) or an etching process such as dry etching, remove a portion of the height of the first mask layer 140 and a portion of the spacer 130 in the vertical direction until the etch stop layer 122 in the mask structure 120 is exposed. In other embodiments, the etch stop layer 122 may also be referred to as a barrier layer. In one embodiment, during the execution of step S106, all of the first mask layer 140 that is higher than the top surface of the etch stop layer 122 in the vertical direction and the spacer 130 located on the top surface of the etch stop layer 122 are mainly removed, and the remaining spacers 130 after removal are only located within the gaps between adjacent mask structures 120, forming a spacer structure in the shape of a "U" as shown in Figure 5 shown.
[0053] It should be understood that in the embodiments of the present invention, the first mask layer remaining in the gap between adjacent mask structures 120 after performing this step is denoted by reference numeral 141 for easy distinction from the previous first mask layer 140; specifically, the spacer structure in the shape of a "U" may include spacers 131 on the sidewalls of the first mask layer 141 remaining between adjacent mask structures 120 and spacers 132 on the bottom of the first mask layer 141 remaining between adjacent mask structures 120.
[0054] In one embodiment, after forming the spacer structure in the shape of a "U" as shown in Figure 5 shown, an etching process may be continued on the spacer structure in the shape of a "U" remaining between adjacent mask structures 120 to remove the spacers 131 on the sidewalls of the first mask layer 141 between adjacent mask structures 120 and retain the spacer walls 132 on the bottom surface of the first mask layer 141 between adjacent mask structures 120. Then, the etch stop layer 122 is removed to form a structure as shown in Figure 6a shown, that is, adjusting the spacer structure in the shape of a "U" as shown in Figure 5 to a "one" shape; then, the second mask layer 121 in the mask structure 120 and the remaining first mask layer 141 between adjacent mask structures 120 are removed to form a structure as shown in Figure 7 shown, and step S107 as above is performed.
[0055] In another embodiment, after forming the spacer structure in the shape of a "U" as shown in Figure 5 shown, the etch stop layer 122 may also be directly removed, and then the second mask layer 122 in the mask structure 120 and the remaining first mask layer 141 between adjacent mask structures 120 are removed to form Figure 6bThe structure shown, and perform step S107 above.
[0056] Obviously, the widths of the partition wall structures in the shape of "one" and the partition wall structures in the shape of "凵" formed by the two embodiments of the present invention as described above are different in the horizontal direction. Therefore, when in subsequent step S107, the remaining partition wall structures in the shape of "one" and the partition wall structures in the shape of "凵" on the substrate 100 are used as masks to further form patterns in the target layer 110, the corresponding patterns are also different in width in the horizontal direction, that is, the width of the pattern formed with the remaining partition wall structures in the shape of "one" as the mask is smaller in the horizontal direction than the width of the pattern formed with the remaining partition wall structures in the shape of "凵" as the mask in the horizontal direction.
[0057] Please refer to Figure 8 , perform the above step S107. Further, the remaining partition wall structures in the shape of "one" ( Figure 7 shown) or the remaining partition wall structures in the shape of "凵" ( Figure 6b shown) can be used as masks to etch the target layer 110 vertically downward to form a plurality of patterns 111 in the target layer 110. And when the material of the target layer 110 is a metal material (such as tungsten), the pattern 111 can be used as an alignment mark for semiconductor devices such as DRAM, but not limited thereto. Obviously, in the process of forming the partition wall structures in the shape of "凵" or "one" as masks for forming the pattern 111 in the embodiments of the present invention, it does not perform layer-by-layer pattern transfer with the axis structure commonly used in the existing patterning process as the mask, but performs pattern transfer based on a non-axis structure with a wider width and adjustable width as the mask, that is, it achieves the purpose of adjusting (increasing) the spacing between adjacent patterns formed in the target layer by using the wider non-axis structure, and without additional photomasks, it also achieves the purpose of reducing manufacturing costs and simplifying the manufacturing process.
[0058] Please refer to Fig. 9 , following step S107, then further a deposition process can be used to form an insulating layer 150 in the gaps between the patterns 111 for isolating adjacent patterns 111. Exemplarily, the material of the insulating layer 150 is an oxide such as silicon dioxide, or can also be a nitride such as silicon nitride, but not limited thereto.
[0059] It should be understood that "conformal" in the embodiments of the present invention means constructing a continuous structural shape by utilizing the similarity and correlation in the morphology between two or more shapes.
[0060] In summary, the present invention removes the mask structure serving as the axial structure and the partition walls on its top surface and side walls, and allows the remaining partition walls at the non-axial structure to serve as a mask for the subsequent patterning process, thereby achieving the purpose of adjusting (increasing) the spacing between adjacent patterns formed in the target layer using the non-axial structure with a wider width, without the need for additional masks, and also achieving the purpose of reducing manufacturing costs and simplifying the process.
[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.
Claims
1. A patterning method, characterized in that: Comprising: Providing a substrate; Forming a target layer on the substrate; Forming a plurality of mutually separated mask structures on the target layer; Forming a spacer covering the mask structures and the target layer; Forming a first mask layer covering the spacer and at least filling the gaps between adjacent mask structures; Removing the mask structures, the first mask layer, and part of the spacer, and retaining part of the spacer wall; Using the remaining spacer as a mask to etch the target layer and form a pattern, the pattern being aligned with the remaining spacer; 2. The patterning method according to claim 1, characterized in that The mask structure includes a second mask layer and an etch stop layer stacked in sequence from bottom to top; 3. The patterning method according to claim 1, characterized in that The remaining spacer is located on the bottom surface of the first mask layer between adjacent mask structures and is in the shape of a "one" character; 4. The patterning method according to claim 1, characterized in that: The remaining spacer is located on the side wall and the bottom surface of the first mask layer between adjacent mask structures and is in the shape of a "U" character; 5. The patterning method according to claim 2, characterized in that: The step of removing the mask structures, the first mask layer, and part of the spacer includes: Performing an etching process on the spacer on the top surface of the first mask layer and the mask structures until the etch stop layer in the mask structures is exposed; Continuing to perform an etching process on the remaining spacer between adjacent mask structures to remove the spacer on the side wall of the first mask layer between adjacent mask structures and retaining part of the spacer wall on the bottom surface of the first mask layer between adjacent mask structures; Removing the etch stop layer; 6. The patterning method according to claim 2, characterized in that: The step of removing the mask structures, the first mask layer, and part of the spacer includes: Performing an etching process on part of the spacer on the top surface of the first mask layer and the mask structures until the etch stop layer in the mask structures is exposed and retaining part of the spacer wall on the side wall and the bottom surface of the first mask layer between adjacent mask structures; Removing the etch stop layer; 7. The patterning method according to claim 5 or 6, characterized in that: After removing the mask structures, the first mask layer, and part of the spacer, further including: Removing the second mask layer in the mask structures and the remaining first mask layer between adjacent mask structures; 8. The patterning method according to claim 4, characterized in that: The width of the pattern formed using the remaining spacer in the shape of a "one" character as a mask is smaller in the horizontal direction than the width of the pattern formed using the remaining spacer in the shape of a "U" character as a mask; 9. The patterning method according to claim 1, characterized in that: Further including: Forming an insulating layer to fill the voids between adjacent patterns; 10. The patterning method according to claim 2, characterized in that: The materials of the first mask layer and the second mask layer are the same; 11. The patterning method according to claim 1, characterized in that: The target layer includes a metal material.