阅读说明：本技术 微纳光学器件制造方法 (Method for manufacturing micro-nano optical device ) 是由 王淼 于 2020-12-31 设计创作，主要内容包括：本申请公开了一种微纳光学器件制造方法,该方法包括：利用半导体光刻和刻蚀工艺在晶圆上形成第一微纳结构；在晶圆上涂敷光刻胶；将第一区域中的光刻胶完全移除,以露出至少部分第一微纳结构,并对第二区域中的光刻胶进行灰度曝光,以在第二区域的光刻胶上形成第二微纳结构；以及将第一和第二微纳结构转印到待加工材料的表面上。根据本发明实施例,通过在已经经过半导体光刻刻蚀工艺处理的晶圆上涂覆灰度曝光用的光刻胶并选择性地进行部分区域的完全除胶和部分区域的灰度曝光,在一个统一的制作流程中融合了两种不同的微纳结构制作工艺；相应地,可以实现不同的微纳结构的构造制作。(The application discloses a method for manufacturing a micro-nano optical device, which comprises the following steps: forming a first micro-nano structure on a wafer by utilizing semiconductor photoetching and etching processes; coating photoresist on the wafer; completely removing the photoresist in the first region to expose at least part of the first micro-nano structure, and carrying out gray exposure on the photoresist in the second region to form a second micro-nano structure on the photoresist in the second region; and transferring the first and second micro-nano structures to the surface of the material to be processed. According to the embodiment of the invention, two different micro-nano structure manufacturing processes are fused in a unified manufacturing flow by coating photoresist for gray exposure on a wafer which is processed by a semiconductor photoetching process and selectively carrying out complete photoresist removal on partial regions and gray exposure on partial regions; accordingly, the construction and manufacturing of different micro-nano structures can be realized.)

1. A manufacturing method of a micro-nano optical device comprises the following steps:

forming a first micro-nano structure on at least part of the surface of the wafer by utilizing semiconductor photoetching and etching processes;

coating photoresist on the wafer, wherein the photoresist covers the whole surface of the wafer with the first micro-nano structure;

photoetching the photoresist, wherein the photoresist in a first region is completely removed to expose at least part of the first micro-nano structure, and gray level exposure is carried out on the photoresist in a second region to form a second micro-nano structure on the photoresist in the second region; and

and transferring the first micro-nano structure and the second micro-nano structure onto the surface of a material to be processed.

2. The method for manufacturing the micro-nano optical device according to claim 1, wherein the first micro-nano structure is formed on the whole surface of the wafer.

3. The method for manufacturing the micro-nano optical device according to claim 1 or 2, wherein the first region is adjacent to the second region.

4. The method for manufacturing the micro-nano optical device according to claim 1 or 2, wherein the first micro-nano structure has a step-like morphology; the second micro-nano structure has a curved surface appearance.

5. The method for manufacturing the micro-nano optical device according to claim 4, wherein the first micro-nano structure is a step-like morphology corresponding to a surface structure of a diffractive optical element, and the second micro-nano structure is a curved surface morphology corresponding to a micro-lens array.

6. The method for manufacturing the micro-nano optical device according to claim 1 or 2, wherein the step of transferring the first micro-nano structure and the second micro-nano structure onto the surface of the material to be processed comprises:

transferring the first micro-nano structure and the second micro-nano structure onto a flexible substrate to form a flexible template; and

and transferring the surface of the material to be processed by using the flexible template.

7. The method of fabricating a micro-nano optical device according to claim 6, wherein the step of transferring the first micro-nano structure and the second micro-nano structure onto a flexible substrate to form a flexible template comprises:

electroplating is carried out on the wafer with the first micro-nano structure and the second micro-nano structure to obtain a nickel plate with surface appearances corresponding to the first micro-nano structure and the second micro-nano structure; and

and stamping the flexible substrate by using the nickel plate to obtain the flexible template.

8. The method of fabricating a micro-nano optical device according to claim 6, wherein the step of transferring the first micro-nano structure and the second micro-nano structure onto a flexible substrate to form a flexible template comprises:

and directly forming the flexible template by casting or impressing the wafer on which the first micro-nano structure and the second micro-nano structure are formed.

9. The method for manufacturing the micro-nano optical device according to any one of claims 6 to 8, wherein the flexible substrate is a PDMS material.

10. The method for manufacturing the micro-nano optical device according to any one of claims 6 to 8, wherein the material to be processed is a polymer material formed on a glass or PET substrate.

Technical Field

The invention relates to a micro-nano optical device manufacturing technology, in particular to a manufacturing method of a micro-nano optical device integrating different types of micro-nano optical structures.

Background

Micro-nano optics is an important development direction of the current photoelectron industry, and plays a great role in various fields such as optical communication, optical interconnection, optical storage, semiconductor devices and the like. A micro-nano optical element generally refers to a micro-nano level element that realizes a novel optical function by introducing a micro-nano optical structure into a material through means such as photolithography, electrodeposition, or micro-nano imprinting. Micro-nano optical elements include, for example, DOE (Diffractive optical Element), MLA (Micro Lens Array), and super surface (Metasurface) optics, and the like.

In some applications, different micro-nano optical elements may be integrated together to form a micro-nano optical device with integrated functionality. However, the structural and dimensional characteristics of different micro-nano optical elements often have many differences, and thus are often different in processing. For example, the microstructure surface topography angle of the DOE is approximately vertical (generally greater than 87 °), and is step-like, and the lateral dimension and longitudinal depth of the microstructure are generally in the order of submicron or several microns, and the template for manufacturing the DOE can be fabricated on a wafer through well-established semiconductor lithography and etching processes; the microstructure appearance of the MLA light homogenizing sheet is mostly curved surface, the transverse size and the same longitudinal depth of the surface shape of a single micro lens are generally tens of micrometers to tens of micrometers, even hundreds of micrometers, and the surface shape of the lens can expose and develop the microstructure on the photoresist through the processes of laser direct writing exposure and the like to form a template for manufacturing the MLA. It can be seen that a single processing technology does not meet the requirements of precision and size range of different micro-nano optical structures, and under the condition of the prior art, two structures are difficult to be simultaneously manufactured on the same template.

Disclosure of Invention

The invention aims to provide a method for manufacturing a micro-nano optical device, which can manufacture two different micro-nano optical structures on the same template and at least partially makes up the defects in the prior art.

According to an aspect of the present invention, there is provided a method for manufacturing a micro-nano optical device, the method including:

forming a first micro-nano structure on at least part of the surface of the wafer by utilizing semiconductor photoetching and etching processes;

coating photoresist on the wafer, wherein the photoresist covers the whole surface of the wafer with the first micro-nano structure;

photoetching the photoresist, wherein the photoresist in the first region is completely removed to expose at least part of the first micro-nano structure, and carrying out gray exposure on the photoresist in the second region to form a second micro-nano structure on the photoresist in the second region; and

and transferring the first micro-nano structure and the second micro-nano structure onto the surface of the material to be processed.

Preferably, the first micro-nano structure is formed on the entire surface of the wafer.

Preferably, the first region is contiguous with the second region.

Preferably, the first micro-nano structure has a step-shaped morphology; the second micro-nano structure has a curved surface appearance. In an advantageous embodiment, the first micro-nano structure may be a step-like topography corresponding to a surface structure of the diffractive optical element, and the second micro-nano structure may be a curved surface topography corresponding to the microlens array.

In an advantageous embodiment, the step of transferring the first micro-nano structure and the second micro-nano structure onto the surface of the material to be processed may include: transferring the first micro-nano structure and the second micro-nano structure onto a flexible substrate to form a flexible template; and transferring the surface of the material to be processed by utilizing the flexible template.

In an advantageous embodiment, the step of transferring the first micro-nano structure and the second micro-nano structure onto the flexible substrate to form the flexible template may comprise: electroplating is carried out on the wafer with the first micro-nano structure and the second micro-nano structure to obtain a nickel plate with surface appearances corresponding to the first micro-nano structure and the second micro-nano structure; and stamping the flexible substrate by using a nickel plate to obtain the flexible template.

In other advantageous embodiments, the step of transferring the first micro-nano structure and the second micro-nano structure onto a flexible substrate to form a flexible template comprises: and directly forming a flexible template by casting or impressing the wafer with the first micro-nano structure and the second micro-nano structure.

Preferably, the flexible substrate is a PDMS material.

Preferably, the material to be processed is a polymeric material formed on a glass or PET substrate.

According to the manufacturing method of the micro-nano optical device, the photoresist for gray level exposure is coated on the wafer which is processed by the semiconductor photoetching process, complete photoresist removal of partial areas and gray level exposure of partial areas are selectively carried out, and two different micro-nano structure manufacturing processes are fused in one unified manufacturing flow; correspondingly, the construction and manufacturing of different micro-nano structures can be realized by utilizing two different micro-nano structure manufacturing processes. According to the manufacturing method of the micro-nano optical device, the micro-nano optical device is well integrated in process, simple in process and low in cost, and the micro-nano optical device with high integration level can be manufactured.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a flowchart of a method for manufacturing a micro-nano optical device according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of a first micro-nano optical structure and a second micro-nano optical structure in an exemplary process of forming the first micro-nano optical structure and the second micro-nano optical structure on a wafer according to an embodiment of the invention;

fig. 3 is a top view of a wafer during an exemplary process of forming first and second micro-nano optical structures on the wafer according to an embodiment of the invention;

fig. 4 schematically illustrates an example of a region where a first micro-nano optical structure is formed on a wafer and first and second regions in a gray scale exposure in the exemplary process shown in fig. 3;

fig. 5 is a top view of a wafer during another exemplary process of forming first and second micro-nano optical structures on the wafer according to an embodiment of the invention;

fig. 6 schematically illustrates an example of a region where a first micro-nano optical structure is formed on a wafer and first and second regions in a gray scale exposure in the exemplary process shown in fig. 5;

fig. 7 is a top view of a wafer in a further exemplary process of forming first and second micro-nano optical structures on the wafer according to an embodiment of the invention;

fig. 8 schematically illustrates an example of a region where a first micro-nano optical structure is formed on a wafer and first and second regions in a gray scale exposure in the exemplary process shown in fig. 7;

fig. 9 shows another example of the configuration of the first region and the second region in the gray-scale exposure;

fig. 10 is a flow chart of a method for transferring first and second micro-nano structures on a wafer to a surface of a material to be processed, which can be used in the method shown in fig. 1;

FIG. 11 is an exemplary cross-sectional view of a staged structure resulting from the method shown in FIG. 10; and

fig. 12 is a schematic view of an example of a micro-nano optical device that can be manufactured using a method according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. For convenience of description, only portions related to the invention are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Fig. 1 is a flowchart of a method 100 for manufacturing a micro-nano optical device according to an embodiment of the present invention. As shown in fig. 1, the method 100 for manufacturing a micro-nano optical device includes the following steps:

s110: forming a first micro-nano structure on at least part of the surface of the wafer by utilizing semiconductor photoetching and etching processes;

s120: coating photoresist on the wafer, so that the photoresist covers the whole surface of the wafer with the first micro-nano structure;

s130: photoetching the photoresist, wherein the photoresist in the first region is completely removed to expose at least part of the first micro-nano structure, and carrying out gray exposure on the photoresist in the second region to form a second micro-nano structure on the photoresist in the second region; and

s140: and transferring the first micro-nano structure and the second micro-nano structure onto the surface of the material to be processed.

For ease of understanding, a cross-sectional view of the structure in an exemplary process of forming first and second micro-nano optical structures on a wafer using the method 100 is shown in fig. 2. With combined reference to fig. 1 and 2, in a process S110, a first micro-nano structure 11 is formed on a wafer 10 by using a semiconductor lithography and etching process. As shown in the graph (2a) of fig. 2, the first micro-nano structure 11 may have a step-like morphology 11 a; for example only, the first micro-nano structure 11 may have a step-like topography corresponding to the surface structure of the DOE element.

As shown in fig. 2 (2b), in the process S120, a photoresist 20 is coated on the wafer 10 on which the first micro-nano structure 11 is formed, so that the photoresist 20 covers the entire surface of the wafer 10 on which the first micro-nano structure 11 is formed. The photoresist coating is performed by, for example, spin coating. The photoresist may be selected to be thick enough for gray scale exposure, for example.

Next, in a process S130, performing photolithography on the photoresist 20 to achieve different photolithography effects in different regions of the surface of the wafer 10, wherein the photoresist is completely removed in the first region a to expose the first micro-nano structure 11 in the region; and performing gray scale exposure on the photoresist in the second region B, thereby forming a second micro-nano structure 21 on the photoresist 20 in the second region B. The processing of the photoresist in the first area a and the second area B may be performed in one gray scale exposure, except that the degree of gray scale exposure in different areas is different, the exposure intensity in the first area a is enough to remove the photoresist completely, and the exposure intensity in the second area B forms the second micro-nano structure 21 in the photoresist 20. Of course, more than one exposure may be performed in the process S130 to obtain the structures in the first and second regions a and B. The "gray-scale exposure" can be realized by a technique such as laser direct-write exposure, gray-scale mask exposure, or two-photon interference exposure. As shown in graph (2c) of fig. 2, the second micro-nano structure 21 may have a curved surface topography 21 a; for example only, the second micro-nano structure 21 may have a curved topography corresponding to an MLA.

Finally, the first micro-nano structure 11 and the second micro-nano structure 21 are transferred onto the surface of the material to be processed in process S140 to manufacture the micro-nano optical device 50 having micro-nano optical elements corresponding to the first micro-nano structure 11 and the second micro-nano structure 21 (see fig. 12). This will be described in more detail below in connection with fig. 10-12.

In the example shown in fig. 2, a first region a with a surface topography of the first micro-nano structure 11 and a second region B with a surface topography of the second micro-nano structure 21 are adjacent to each other; in this way, in the micro-nano optical device manufactured by the transfer process in the process S140, micro-nano optical elements corresponding to the first micro-nano structure 11 and the second micro-nano structure 21 may be integrated adjacent to each other, which is beneficial to reduce the size of the device and/or improve the optical performance of the device, for example, reduce stray light caused by light leakage in the gap region between the micro-nano optical elements.

A plurality of first regions a and a plurality of second regions B (see fig. 3, 5 and 7) may be included on the wafer 10, and the first micro/nano structure 11 may be formed on the entire surface of the wafer 10 or only a part of the surface of the wafer 10 in the process S110, which may affect subsequent processes and the resulting structure. For ease of understanding, reference will be made below to fig. 3 to 9 in connection with different embodiments. It should be noted that the positional relationship of the first region a and the second region B discussed below is for the adjacent first region a and second region B on which the micro-nano structure is to be transferred to the same micro-nano optical device.

Fig. 3 is a schematic diagram of an exemplary process for forming first and second micro-nano structures on a wafer using the method 100, wherein graphs (3a), (3b), and (3c) respectively show top views of the wafer corresponding to the structures obtained in processes S110, S120, and S130 of the method 100. As shown in the graph (3a), the first micro-nano structure 11 is formed on the entire surface of the wafer 10 in the process S110; in the process S130, the photoresist 20 is removed in the first region a, the first micro-nano structure 11 in the region is exposed, and the photoresist 20 is subjected to gray scale exposure in the second region B to form the second micro-nano structure 21. Other structures may or may not be formed on the photoresist 20 in the region C (see fig. 4) other than the first region a and the second region B, and the present invention is not limited in this respect.

Fig. 4 is an enlarged view of an example of a region where a first micro-nano optical structure is formed on a wafer in the exemplary process shown in fig. 3 and first and second regions in a gray scale exposure. As shown in fig. 4 (4a), a first micro/nano structure 11 is formed on the entire surface of the wafer 10 in process S110; as shown in fig. 4 (4B), the second region B where the second micro/nano structure 21 is formed is adjacent to/adjacent to the first region a. Furthermore, since the first micro-nano structure 11 initially covers the entire wafer surface, it can be known that the second micro-nano structure 21 is superposed on a part of the first micro-nano structure 11.

Similarly, fig. 5 and 6 illustrate another exemplary process of forming first and second micro-nano structures on a wafer using the method 100. As shown in fig. 5 and 6, in the process S110, the first micro-nano structure 11 is formed on a plurality of local regions of the wafer 10, where the local regions correspond to the first region a; in the process S130, the photoresist 20 in the first region a is removed to expose the first micro-nano structure 11, and the photoresist 20 is subjected to gray scale exposure in the second region B to form a second micro-nano structure 21. The photoresist 20 of the region C (see fig. 6) outside the first region a and the second region B may be removed or partially removed, may remain, or may form other structures on the photoresist 20; however, the invention is not limited in this respect. As shown more clearly in fig. 6, the first area a and the second area B may be adjacent rather than abutting/contiguous. Since the first micro-nano structure 11 is formed only on the first region a of the target in the process S110, it is difficult to achieve non-biased alignment of the second region B with the first region a in the process S130, in which case the first region a and the second region B may not be adjacent, however, the present invention is not limited thereto, and in other embodiments, the first region a and the second region B may be made adjacent/adjacent by fine alignment.

Similarly, fig. 7 and 8 illustrate yet another exemplary process for forming first and second micro-nano structures on a wafer using the method 100. As shown in fig. 7 and 8, in the process S110, the first micro-nano structure 11 is formed on a plurality of local regions of the wafer 10, where the local regions are larger than the first region a, for example, include at least a part of the second region B; in the process S130, the photoresist 20 in the first region a is removed to expose the first micro-nano structure 11, and the photoresist 20 is subjected to gray scale exposure in the second region B to form a second micro-nano structure 21. In this case, the photoresist 20 of the region C (see fig. 8) other than the first and second regions a and B may be left, or other structures may be formed on the photoresist 20; however, the present invention is not limited thereto. As more clearly shown in fig. 8, the second region B where the second micro-nano structure 21 is formed is adjacent/contiguous to the first region a. Furthermore, since the first micro-nano structure 11 initially covers a larger area than the first area a, it can be known that the second micro-nano structure 21 is partially overlapped on the first micro-nano structure 11.

Further, fig. 3 to 8 each show the first area a and the second area B as rectangular areas arranged side by side, however, the present invention is not limited thereto. For example, fig. 9 shows another exemplary configuration of a first area a and a second area B, in which the first area a surrounds the second area B, and both the first area a and the second area B are rectangular areas. Although not shown, it is understood that the two regions may each have a different shape, such as rectangular, circular, and the like.

The processes S110, S120, and S130 of the micro-nano optical device manufacturing method 100 according to the embodiment of the present invention are described in detail with reference to fig. 2 to 9. A flow chart of a micro-nano transfer method 200 that can be used in the process S140 of the method 100 will be described below with reference to fig. 10 to 11.

As shown in fig. 10, the micro-nano transfer printing method 200 includes the following processes:

s210: electroplating is carried out on the wafer with the first micro-nano structure and the second micro-nano structure to obtain a nickel plate with surface appearances corresponding to the first micro-nano structure and the second micro-nano structure;

s220: stamping the flexible substrate by using a nickel plate to obtain a flexible template; and

s230: and transferring the surface of the material to be processed by utilizing the flexible template.

Fig. 11 illustrates, in a cross-sectional view, an example of a stepped structure obtained in the method illustrated in fig. 10, wherein reference numeral "31" denotes a nickel plate obtained by the process S210, and the surface morphology of the nickel plate 31 is complementary to the surface morphology of the first micro-nano structure 11 and the second micro-nano structure 21 (see graph (2c) in fig. 2); reference numeral "32" denotes a flexible template obtained by the process S220; the surface topography of the flexible template 32 is complementary to that of the nickel plate 31, so that the surface topography is the same as that of the first micro-nano structure 11 and the second micro-nano structure 21 formed on the wafer 10. In the process S220, the flexible substrate used for forming the flexible template 32 may be, for example, PDMS (Polydimethylsiloxane), PUA (polyurethane acrylate), or the like.

Although fig. 10 and 11 illustrate that a nickel plate is first obtained through electroplating and then a flexible template is obtained through imprinting of the nickel plate, in other cases, a nickel plate may be omitted in a micro-nano transfer printing method for transferring a first micro-nano structure and a second micro-nano structure formed on a wafer onto a product to be processed, and the flexible template is formed through casting or imprinting directly using the wafer on which the first micro-nano structure and the second micro-nano structure are formed. At the moment, the flexible template has a surface appearance complementary with the first micro-nano structure and the second micro-nano structure.

Then, the micro-nano structure on the flexible template 32 is transferred to a material to be processed, and the material to be processed 41 may be a polymer material, such as UV glue, formed on a glass substrate or a PET (polyethylene terephthalate) substrate 42, for example. An example of the resulting transfer structure 40 is shown in graph (11c) of fig. 11, where the surface of the material 41 is formed with features 41a, 41b corresponding to the first micro-nano structure 11 and the second micro-nano structure 21.

In order to manufacture the final micro-nano optical device, after the transfer structure 40 is obtained, processes such as cutting, assembling, packaging and the like are required, which can be implemented by existing technologies and are not described herein again.

Finally, as an example only, an example of a micro-nano optical device manufactured by the micro-nano optical device manufacturing method 100 according to an embodiment of the present invention is shown in fig. 12. As shown in fig. 12, the micro-nano optical device 50 includes a substrate 50a, and a first micro-nano optical element 51 and a second micro-nano optical element 52 formed on the substrate 50 a. The substrate 50a may be formed of the substrate 42 in the transfer structure 40, for example, or may be further combined with other substrate structures. The first micro-nano optical element 51 and the second micro-nano optical element 52 are respectively formed by portions of the transfer structure 40 having the surface topographies 41a and 41b, and respectively correspond to the first micro-nano structure 11 and the second micro-nano structure 21 formed on the wafer 10. For example only, the first micro-nano optical element 51 and the second micro-nano optical element 52 may be DOE and MLA elements, respectively.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.