CN118016522B - Silicon column structure based on overexposure and preparation method thereof - Google Patents

Abstract

The present application provides a silicon pillar structure based on overexposure and a preparation method thereof, which relates to the field of electronic manufacturing, including: providing a silicon-based substrate; forming a mask layer on one side of the silicon-based substrate; overexposing the mask layer based on a laser direct writing lithography process to form a plurality of first through holes corresponding to a plurality of first regions, wherein the sidewall portions of adjacent first through holes along the row direction and the column direction are connected to form a plurality of first structures arranged in an array in the second region; etching the side of the silicon-based substrate close to the mask layer based on the plurality of first structures to form a plurality of silicon pillars corresponding to the plurality of first structures. The present application uses a laser direct writing lithography process to expose the mask layer, which reduces the requirements for lithography accuracy, and forms a plurality of first structures of smaller size by overexposure, thereby obtaining silicon pillars with a high feature ratio based on etching of the first structures, effectively reducing the process complexity and process cost of preparing silicon pillar structures with a high feature ratio.

Description

A silicon column structure based on overexposure and preparation method thereof

Technical Field

The embodiments of the present application relate to the field of electronic manufacturing, and more specifically, to an overexposure-based silicon pillar structure and a method for preparing the same.

Background Art

Due to the constraint effect and maximum surface area effect of micro-pillars and nano-pillars, they play a key role in many emerging technologies and are widely used in electronics, optics, chemical synthesis and catalysis, biosensing, etc. The silicon pillar structure has the advantage of being compatible with CMOS (Complementary Metal Oxide Semiconductor) technology, so it is favored in MEMS (Micro-Electromechanical System) and other fields.

However, in the existing method for preparing silicon pillar structures, when preparing silicon pillar structures of smaller size, on the one hand, the thickness of the mask for electron beam lithography spin coating is smaller than the conventional thickness, and on the other hand, due to the limitation of etching selectivity, a metal mask needs to be prepared for pattern transfer, which makes the process complexity and process cost of preparing silicon pillar structures with high feature ratios high. Therefore, how to reduce the complexity and process cost of the process for preparing silicon pillar structures with high feature ratios has become a problem that needs to be solved urgently in the field.

Summary of the invention

The embodiments of the present application provide a silicon pillar structure based on overexposure and a method for preparing the same, aiming to solve the problem of how to reduce the complexity and process cost of the preparation process of a silicon pillar structure with a high feature ratio.

A first aspect of an embodiment of the present application provides a method for preparing a silicon pillar structure based on overexposure, the method comprising:

Providing a silicon-based substrate;

Forming a mask layer on one side of the silicon-based substrate, the mask layer comprising a plurality of first regions arrayed in a row direction and a column direction, and a second region surrounding the first regions;

Performing an overexposure process on the mask layer based on a laser direct writing lithography process to form a plurality of first through holes corresponding to the plurality of first regions, wherein the plurality of first through holes penetrate the mask layer, wherein sidewall portions of adjacent first through holes along the row direction and the column direction are connected to form a plurality of first structures arranged in an array in the second region;

Based on the multiple first structures, a side of the silicon-based substrate close to the mask layer is etched to form a plurality of silicon pillars corresponding to the multiple first structures.

In an optional implementation, the over-exposure treatment of the mask layer based on the laser direct writing process to form a plurality of first through holes corresponding to the plurality of first regions includes:

Based on the laser direct writing lithography process, the multiple first regions are overexposed to remove the mask material of the first regions and part of the mask material between adjacent first regions to form the multiple first through holes, wherein the first structure includes the mask material between two adjacent first through holes along a first direction, and the first direction is a direction parallel to the diagonal of the first region.

In an optional implementation, etching a side of the silicon-based substrate close to the mask layer based on the multiple first structures to form a plurality of silicon pillars corresponding to the multiple first structures includes:

Deep silicon etching is performed on one side of the silicon-based substrate close to the mask layer to increase the depth of the first through hole along the second direction to form a plurality of blind holes, and the plurality of silicon pillars are formed between adjacent blind holes, wherein the second direction is the direction from the silicon-based substrate to the mask layer.

In an optional implementation, the mask layer is a photoresist layer.

In an optional implementation, the mask layer includes a stacked photoresist layer and a metal layer, the metal layer is disposed on one side of the silicon-based substrate, and the photoresist layer is disposed on a side of the metal layer away from the silicon-based substrate.

In an optional implementation, the height of the silicon pillar along the second direction is greater than or equal to 15 μm, the diameter of the silicon pillar is less than or equal to 1 μm, and the second direction is the direction from the silicon-based substrate to the mask layer.

In an optional implementation, the orthographic projection shape of the first region on the silicon-based substrate is a rectangle.

In an optional embodiment, the ratio of the width of the first through hole along the row direction to the width of the first region along the row direction is greater than or equal to 2:1 and less than or equal to (√2+1):1.

In an optional embodiment, the width of the first region along the row direction or the column direction is less than or equal to 2 μm; the gap width between adjacent first regions along the row direction or the column direction is the same as the width of the first region along the row direction or the column direction.

A second aspect of an embodiment of the present application provides a silicon column structure based on overexposure, wherein the silicon column structure is prepared by using any one of the methods for preparing a silicon column structure based on overexposure described in the first aspect.

Beneficial effects:

The present application provides a silicon pillar structure based on overexposure and a preparation method thereof, the preparation method comprising: providing a silicon-based substrate; forming a mask layer on one side of the silicon-based substrate, the mask layer comprising a plurality of first regions arranged in an array along the row direction and the column direction, and a second region surrounding the first region; overexposing the mask layer based on a laser direct writing process to form a plurality of first through holes corresponding to the plurality of first regions, the plurality of first through holes passing through the mask layer, wherein the sidewall portions of adjacent first through holes along the row direction and the column direction are connected to form a plurality of first structures arranged in an array in the second region; etching the side of the silicon-based substrate close to the mask layer based on the plurality of first structures to form a plurality of silicon pillars corresponding to the plurality of first structures. The present application uses a laser direct writing lithography process to expose the mask layer, which reduces the requirements for lithography accuracy, and forms a plurality of first structures of smaller size by overexposure, thereby etching a silicon pillar with a high feature ratio based on the first structure, effectively reducing the process complexity and process cost of preparing a silicon pillar structure with a high feature ratio.

The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

FIG1 is a flow chart of a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

FIG2 is a schematic top view of forming a mask layer in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

FIG3 is a schematic cross-sectional view of A-A’ of forming a mask layer in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

FIG4 is a schematic cross-sectional view of another method for forming a mask layer in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

5 is a schematic top view of forming a first through hole in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

FIG6 is a schematic top view of another method for forming a first through hole in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

FIG7 is a schematic cross-sectional view taken along line B-B' of forming a first through hole in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application;

FIG8 is a schematic diagram of the A-A’ cross section of a silicon pillar formed in a method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application.

Explanation of the reference numerals: 101, silicon-based substrate; 102, mask layer; 1021, photoresist layer; 1022, metal layer; 103, first through hole; 104, first structure; 105, blind hole; 106, silicon pillar; 201, first region; 202, second region.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

In the drawings, the size of the constituent elements, the thickness of the layer or the area may be exaggerated for the sake of clarity. Therefore, any implementation of the present disclosure is not necessarily limited to the size shown in the drawings, and the shapes and sizes of the components in the drawings do not reflect the true proportions. In addition, the drawings schematically show ideal examples, and any implementation of the present disclosure is not limited to the shapes or values shown in the drawings.

Due to the constraint effect and maximum surface area effect of micro-pillars and nano-pillars, they play a key role in many emerging technologies and are widely used in electronics, optics, chemical synthesis and catalysis, biosensing, etc. The silicon pillar structure has the advantage of being compatible with CMOS (Complementary Metal Oxide Semiconductor) technology, so it is favored in MEMS (Micro-Electromechanical System) and other fields.

In the prior art, the preparation methods of silicon column structures are generally divided into two categories. One is the silicon column growth technology using metal wires such as gold as catalysts, which belongs to the "addition method". The disadvantage of this method is that it requires a harsh environment of high temperature and high vacuum, and the height of the silicon column is uneven; the other method is to remove the parts other than the silicon column on the silicon-based substrate through an etching process, which belongs to the "subtraction method". However, in the existing "subtraction" form of silicon column structure preparation method, electron beam lithography is usually used for etching to form the silicon column structure. When preparing a silicon column structure with a smaller size, on the one hand, the thickness of the mask for electron beam lithography spin coating is smaller than the conventional thickness. On the other hand, due to the limitation of the etching selectivity, a metal mask needs to be prepared for the transfer of the pattern, which makes the process complexity and process cost of preparing a silicon column structure with a high feature ratio higher. It should be noted that the size of the silicon column structure refers to the size of the silicon column structure along the height direction (the direction perpendicular to the upper and lower flat surfaces of the silicon-based substrate) and the size of the silicon column structure along the width direction (the direction parallel to the upper and lower flat surfaces of the silicon-based substrate).

In view of this, an embodiment of the present application proposes a method for preparing a silicon pillar structure based on overexposure. FIG. 1 shows a flow chart of a method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application. As shown in FIG. 1 , the preparation method comprises the following steps:

S101. Provide a silicon-based substrate.

When implementing step S101, the embodiment of the present application uses a silicon chip wafer as the substrate material for generating the silicon pillar structure, wherein the thickness of the silicon-based substrate 101 is greater than the thickness of other hierarchical materials in the silicon pillar structure preparation method. It should be noted that in the silicon pillar structure preparation method provided in the embodiment of the present application, the "thickness" of each partial structure involved refers to the dimension of each partial structure in the direction perpendicular to the upper and lower flat surfaces of the silicon-based substrate 101, that is, the dimension of the silicon-based substrate 101 in the direction of other hierarchical structures formed in the silicon pillar structure preparation method.

S102, forming a mask layer on one side of the silicon-based substrate, wherein the mask layer includes a plurality of first regions arrayed along row and column directions, and a second region surrounding the first regions.

When the step S102 is specifically implemented, FIG2 shows a schematic top view of forming a mask layer in a method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application, and FIG3 shows a schematic cross-sectional view of forming a mask layer in a method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application. As shown in FIG3, a mask layer 102 is first formed on one side of the silicon-based substrate 101, and the thickness of the mask layer 102 is less than the thickness of the silicon-based substrate 101. As shown in FIG2, the mask layer 102 includes a first region 201 and a second region 202 surrounding the first region 201, wherein the first region 201 is used to form a plurality of first through holes on the mask layer 102 based on an exposure process, wherein the first region 201 is arranged in an array along the row direction and the column direction; there is a gap located in the second region 202 between adjacent first regions 201, and the second region 202 is used to form a first structure as a mask for etching the silicon-based substrate 101. It should be noted that, in the embodiment of the present application, the division of the first region 201 and the second region 202 on the mask layer 102 in Figure 2 does not represent that when the mask layer 102 is formed, there are differences in structure and material between the first region 201 and the second region 202, but rather represents that in the subsequent preparation method provided in the embodiment of the present application, the first region 201 and the second region 202 are used to form different structures or are subjected to different preparation processes.

In some optional embodiments, the mask layer 102 is a single-layer structure, and the mask layer 102 is a photoresist layer 1021. The photoresist layer 1021 is formed by spin-coating a photoresist material on one side of the silicon-based substrate 101, and the thickness of the photoresist layer 1021 is less than the thickness of the silicon-based substrate 101. In addition, since a photoresist layer with a smaller thickness needs to form an additional metal layer to realize pattern transfer, the complexity and cost of the preparation process are increased, and the etching process of the metal layer causes the metal mask material to be sputtered to the bottom of the first through hole to form a micro-mask, thereby causing an adverse effect on the deep silicon etching of the silicon-based substrate. Since the embodiment of the present application adopts a laser direct writing photolithography process, the thickness of the mask layer 102 is relatively large, so the mask layer 102 can be set to a single-layer structure with only the photoresist layer 1021, avoiding the process of preparing the metal layer, and effectively reducing the process complexity and preparation cost.

In some optional implementations, FIG4 shows another A-A’ cross-sectional schematic diagram of forming a mask layer in a method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application. As shown in FIG4, the mask layer 102 includes a stacked photoresist layer 1021 and a metal layer 1022, the metal layer 1022 is arranged on one side of the silicon-based substrate 101, and the photoresist layer 1021 is arranged on the side of the metal layer 1022 away from the silicon-based substrate 101. Specifically, a metal mask material is evaporated on a surface of one side of the silicon-based substrate 101 to form the metal layer 1022; then, the photoresist material is spin-coated on a surface of one side of the metal layer 1022 away from the silicon-based substrate 101 to form the photoresist layer 1021. Optionally, the material of the metal layer 1022 includes at least one of the following: titanium (Ti), aluminum (Al), chromium (Cr), etc.

In some optional embodiments, the orthographic projection shape of the first region 201 on the silicon-based substrate 101 is a rectangle, a circle or other irregular shapes. Optionally, the orthographic projection shape of the first region 201 on the silicon-based substrate 101 is a rectangle.

In some optional embodiments, the width of the first region 201 along the row direction or the column direction is less than or equal to 2 μm; the gap width between adjacent first regions 201 along the row direction or the column direction is less than or equal to 2 μm, and is the same as the width of the first region 201 along the row direction or the column direction.

S103 , performing over-exposure processing on the mask layer based on a laser direct writing lithography process to form a plurality of first through holes corresponding to the plurality of first regions, wherein the plurality of first through holes penetrates the mask layer.

The mask layer is overexposed based on a laser direct writing lithography process to form a plurality of first through holes corresponding to the plurality of first regions, and the plurality of first through holes penetrate the mask layer, wherein the side walls of adjacent first through holes are connected along the row direction and the column direction to form a plurality of first structures arranged in an array in the second region.

When the step S103 is specifically implemented, FIG5 shows a schematic top view of forming a first through hole in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application. As shown in FIG5, based on the laser direct writing lithography process, the multiple first regions 201 are overexposed to form multiple first through holes 103 corresponding to the first regions 201, and the orthographic projection area of the first through holes 103 on the silicon-based substrate 101 is larger than the orthographic projection area of the first region 201 on the silicon-based substrate 101, and the orthographic projection of each first region 201 on the silicon-based substrate 101 is located inside the orthographic projection of the corresponding first through hole 103 on the silicon-based substrate 101. FIG7 is a schematic B-B’ cross-sectional view of forming a first through hole in a method for preparing a silicon pillar structure based on overexposure according to an embodiment of the present application. As shown in FIG7, the multiple first through holes 103 penetrate the mask layer 102. Specifically, a laser lithography machine is used to remove the mask material of the first area 201 based on the laser direct writing lithography process. Since the laser direct writing lithography process is used in the embodiment of the present application, the exposure process can be performed with a lower lithography accuracy. Therefore, when the first area 201 is exposed, a portion of the second area 202 located around the first area 201 is also over-exposed, so that part of the mask material between adjacent first areas 201 along the row direction, the column direction and the diagonal direction of the first area is also exposed, and the first area 201 removed by exposure and the part of the second area around the first area 201 form the multiple first through holes 103.

The sidewall portions of adjacent first through holes 103 along the row direction and the column direction are connected to form a plurality of first structures 104 arranged in an array in the second region 202. Specifically, since the first through holes 103 are larger in area than the first region 201 (part of the mask material between adjacent first regions 201 is also exposed), the first through holes 103 are preferably arranged in an array in the second region 202. The gaps between adjacent first through holes 103 are connected, and the sidewall portions of the first through holes 103 originally corresponding to the independent first regions 201 along the row direction and the column direction are connected. Since the diagonal length of the first through holes 103 is longer than the length in the row direction and the column direction, the mask material between two adjacent first through holes 103 along the first direction is partially retained, so that the second region 202 corresponding to the center of the array of four adjacent first through holes 103 is formed with a smaller area of the first structure 104. The first structures 104 are arranged in an array along the row direction and the column direction. The widths of the first structures 104 along the row direction and along the column direction are respectively smaller than the widths of the first region along the row direction and along the column direction. The first direction is a direction parallel to the diagonal of the first region 201.

In some optional embodiments, Figure 6 shows a top-view schematic diagram of another method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application for forming a first through hole. As shown in Figure 6, the adjacent edges of the positive projections of two adjacent first through holes 103 along the row direction or the column direction on the silicon-based substrate 101 coincide, so that the side wall portions of adjacent first through holes 103 along the row direction and the column direction are connected.

In some optional embodiments, in order to further reduce the area of the first structure 104, as shown in Figure 5, the orthographic projections of two adjacent first through holes 103 along the row direction or the column direction on the silicon-based substrate 101 overlap, so that the side wall portions of adjacent first through holes 103 along the row direction and the column direction are connected, forming a plurality of first structures 104 arranged in an array with a smaller area.

In some optional embodiments, the orthographic projection shape of the first structure 104 on the silicon-based substrate 101 is a four-pointed star or a circle. Specifically, after forming a plurality of first structures 104 in a four-pointed star shape, when the silicon-based substrate 101 is etched using the first structure 104 as a mask, due to the reaction between the reaction gas and the sidewall silicon, the lateral expansion phenomenon during the etching process can effectively reduce the protrusion of the first structure 104, so that the orthographic projection shape of the first structure 104 on the silicon-based substrate 101 is a circle.

In some optional embodiments, the ratio of the width of the first through hole 103 along the row direction to the width of the first region 201 along the row direction is greater than or equal to 2:1, and less than or equal to (√2+1):1; the ratio of the width of the first through hole 103 along the column direction to the width of the first region 201 along the column direction is greater than or equal to 2:1, and less than or equal to (√2+1):1.

In some optional implementations, the lithography process based on laser direct writing can be maskless aligner (MLA), direct write lithography (DWL), etc. The laser lithography machine is a laser direct writing lithography machine that can adjust exposure parameters to expand the exposure area.

S104 . Etching a side of the silicon-based substrate close to the mask layer based on the multiple first structures to form a plurality of silicon pillars corresponding to the multiple first structures.

When step S104 is specifically implemented, FIG8 shows an A-A’ cross-sectional schematic diagram of a silicon pillar formed in a method for preparing a silicon pillar structure based on overexposure proposed in an embodiment of the present application. As shown in FIG8 , deep silicon etching is performed on the side of the silicon-based substrate 101 close to the mask layer 102. Since a portion of the side of the silicon-based substrate 101 close to the mask layer 102 is blocked by the multiple first structures 104, the silicon-based substrate material under the corresponding areas of these first structures 104 will not be etched, and the silicon-based substrate material exposed in the first through hole 103 is subjected to deep silicon etching, so that the depth of the first through hole 103 along the second direction continues to increase under the etching process, forming a plurality of blind holes 105, and the depth of the blind hole 105 along the second direction is greater than the depth of the first through hole. The area between adjacent blind holes 105 corresponds to the first structure 104, and the plurality of silicon pillars 106 corresponding to the plurality of first structures 104 are formed between the adjacent blind holes 105, and the second direction is the direction from the silicon-based substrate 101 to the mask layer 102. After obtaining the plurality of silicon pillars 106, the remaining first structure 104 is removed to obtain a silicon pillar structure with a high characteristic ratio. It should be noted that the characteristic ratio mentioned in the embodiment of the present application is a characteristic ratio of the size of the submicron silicon pillar, and the characteristic bit mentioned herein refers to the ratio of the height and diameter (or width) of the silicon pillar prepared by the method for preparing the silicon pillar structure based on overexposure provided in the embodiment of the present application.

In some optional embodiments, the height of the silicon pillar 106 along the second direction is greater than or equal to 15 μm, the diameter of the silicon pillar 106 is less than or equal to 1 μm, and the second direction is the direction from the silicon-based substrate 101 to the mask layer 102 .

In some optional implementations, the deep silicon etching process may adopt any deep silicon etching (DeepReactive Ion Etching) scheme. For example, the deep silicon etching process may be a Bosch process, a pseudo-Bosch process, or the like.

The method for preparing a silicon pillar structure based on overexposure provided in the embodiment of the present application can prepare a silicon pillar structure with a high feature ratio with lower lithography precision. When preparing a high feature ratio silicon pillar structure of the same diameter, the method for preparing a silicon pillar structure based on overexposure provided in the present application has lower requirements for lithography precision. For example, to prepare a silicon pillar with an expected diameter of 200nm, an electron beam lithography preparation process with a lithography precision higher than 100nm is generally used; the method for preparing a silicon pillar structure based on overexposure provided in the present application can reduce the lithography precision to 1μm, achieving a 10% reduction in precision requirements, effectively reducing the difficulty of the preparation process.

The present application provides a silicon pillar structure based on overexposure and a preparation method thereof, the preparation method comprising: providing a silicon-based substrate; forming a mask layer on one side of the silicon-based substrate, the mask layer comprising a plurality of first regions arranged in an array along the row direction and the column direction, and a second region surrounding the first region; overexposure the mask layer based on a laser direct writing lithography process to form a plurality of first through holes corresponding to the plurality of first regions, the plurality of first through holes passing through the mask layer, wherein the sidewall portions of adjacent first through holes along the row direction and the column direction are connected to form a plurality of first structures arranged in an array in the second region; etching the side of the silicon-based substrate close to the mask layer based on the plurality of first structures to form a plurality of silicon pillars corresponding to the plurality of first structures. The present application uses a laser direct writing lithography process to expose the mask layer, which reduces the requirements for lithography accuracy, and forms a plurality of first structures of smaller size by overexposure, thereby etching a silicon pillar with a high feature ratio based on the first structure, effectively reducing the process complexity and process cost of preparing a silicon pillar structure with a high feature ratio.

Based on the same inventive concept, an embodiment of the present application discloses a silicon pillar structure based on overexposure, and the silicon pillar structure is prepared by using any one of the methods for preparing a silicon pillar structure based on overexposure described in the embodiments of the present application.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

In the description of this specification, it should be understood that the terms "center", "thickness", "up", "down", "front", "back", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

The above application provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and/or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and/or settings discussed.

The term "one embodiment", "embodiment" or "one or more embodiments" herein means that a particular feature, structure or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. In addition, please note that the examples of the term "in one embodiment" here do not necessarily all refer to the same embodiment.

In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

The above is a detailed introduction to a silicon pillar structure based on overexposure and a preparation method thereof provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for a person skilled in the art, according to the idea of the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims (9)

1. A method for preparing a silicon pillar structure based on overexposure, characterized in that the preparation method comprises: Providing a silicon-based substrate; A mask layer is formed on one side of the silicon-based substrate, wherein the mask layer includes a plurality of first regions arranged in an array along a row direction and a column direction, and a second region surrounding the first region, wherein the orthographic projection shape of the first region on the silicon-based substrate is a rectangle, and a width of the first region along the row direction or the column direction is less than or equal to 2 μm; The mask layer is overexposed based on a laser direct writing lithography process to form a plurality of first through holes corresponding to the plurality of first regions, wherein the plurality of first through holes penetrate the mask layer, wherein the sidewall portions of adjacent first through holes along the row direction and the column direction are connected to form a plurality of first structures arranged in an array in the second region, wherein the orthographic projection shape of the first structure on the silicon-based substrate is a four-pointed star or a circle; Based on the multiple first structures, a side of the silicon-based substrate close to the mask layer is etched to form a plurality of silicon pillars corresponding to the multiple first structures, wherein the diameter of the silicon pillars is less than or equal to 1 μm. 2. The method for preparing a silicon pillar structure based on overexposure according to claim 1, characterized in that the overexposure treatment of the mask layer based on a laser direct writing process to form a plurality of first through holes corresponding to the plurality of first regions comprises: Based on the laser direct writing lithography process, the multiple first regions are overexposed to remove the mask material of the first regions and part of the mask material between adjacent first regions to form the multiple first through holes, wherein the first structure includes the mask material between two adjacent first through holes along a first direction, and the first direction is a direction parallel to the diagonal of the first region. 3. The method for preparing a silicon pillar structure based on overexposure according to claim 1, characterized in that etching a side of the silicon-based substrate close to the mask layer based on the multiple first structures to form a plurality of silicon pillars corresponding to the multiple first structures comprises: Deep silicon etching is performed on the side of the silicon-based substrate close to the mask layer to increase the depth of the first through hole along the second direction to form a plurality of blind holes, and the plurality of silicon pillars are formed between adjacent blind holes. The second direction is the direction from the silicon-based substrate to the mask layer. 4 . The method for preparing a silicon pillar structure based on overexposure according to claim 1 , wherein the mask layer is a photoresist layer. 5. The method for preparing a silicon pillar structure based on overexposure according to claim 1 is characterized in that the mask layer includes a stacked photoresist layer and a metal layer, the metal layer is arranged on one side of the silicon-based substrate, and the photoresist layer is arranged on a side of the metal layer away from the silicon-based substrate. 6 . The method for preparing a silicon pillar structure based on overexposure according to claim 1 , wherein a height of the silicon pillar along a second direction is greater than or equal to 15 μm, and the second direction is a direction from the silicon-based substrate to the mask layer. 7. The method for preparing a silicon pillar structure based on overexposure according to claim 1 is characterized in that the ratio of the width of the first through hole along the row direction to the width of the first region along the row direction is greater than or equal to 2:1 and less than or equal to (√2+1):1. 8. The method for preparing a silicon pillar structure based on overexposure according to claim 1 is characterized in that a gap width between adjacent first regions along the row direction or the column direction is the same as a width of the first region along the row direction or the column direction. 9. A silicon column structure based on overexposure, characterized in that the silicon column structure is prepared by using the method for preparing a silicon column structure based on overexposure according to any one of claims 1 to 8.