Micro-nano composite photoetching method and system
By combining conductive nanoprobe exposure and ultraviolet lithography, the problems of low efficiency and low resolution in existing micro-nano lithography technologies have been solved, achieving efficient and high-resolution micro-nano pattern fabrication suitable for various conductive substrates.
Patent Information
- Application Number
- CN202610024252.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-09
- Publication Date
- 2026-02-24
AI Technical Summary
In existing micro- and nano-lithography technologies, scanning probe lithography suffers from low efficiency but high resolution, while ultraviolet lithography suffers from low resolution but high efficiency.
By combining conductive nanoprobe exposure technology and ultraviolet lithography technology, nanopatterns are first exposed on photoresist, then positioned using an optical microscopy system, followed by micron pattern exposure, and finally transferred to a conductive substrate by etching technology.
It enables the fabrication of high-resolution and high-efficiency micro- and nano-patterns, reduces equipment costs, improves fabrication flexibility and pattern alignment accuracy, and is applicable to a variety of non-planar conductive substrates.
Smart Images
Figure CN121559819A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a micro / nano composite photolithography method and system, belonging to the technical field of micro / nano structure fabrication. Background Technology
[0002] In recent years, various scanning probe lithography technologies have attracted increasing attention due to their advantages such as high resolution and high flexibility. Among these, conductive scanning probe lithography has become a commonly used scanning probe lithography technology due to its advantages of high resolution, no need for a vacuum environment, high adaptability, and high flexibility.
[0003] In conductive scanning probe microscopy (CSMT) exposure technology, charges are injected into a resin material layer via conductive nanoprobes, causing cross-linking or degradation reactions in the resin material of the charged writing area, resulting in micro / nano patterns in the subsequent development process. Because the tip radius of curvature of conductive nanoprobes is typically very small (generally less than 30 nanometers), this method can achieve very high nanoscale resolution. However, this method involves writing patterns on the resin material surface line by line using conductive nanoprobes, resulting in relatively low processing efficiency. This is especially true for micron-sized patterns with large writing areas, which require a long processing time, limiting the ability of this technology to fabricate multi-scale micro / nano composite patterns.
[0004] On the other hand, ultraviolet lithography has long been used for the fabrication of micro and nano patterns. Common ultraviolet lithography techniques, such as contact ultraviolet lithography and projection ultraviolet lithography, have advantages such as short exposure times and high processing efficiency. However, these ultraviolet lithography techniques have limited resolution, making it difficult to achieve nanoscale resolution.
[0005] In conclusion, a micro-nano composite lithography technology that can simultaneously possess the advantages of high resolution and high processing efficiency is indispensable for the fabrication of increasingly complex and diverse micro-nano patterns. Summary of the Invention
[0006] This invention aims to address the following problems in existing micro / nano lithography technologies: direct-write lithography techniques such as scanning probes typically suffer from drawbacks such as small exposed pattern area, low exposure efficiency, and long processing time; while common maskless ultraviolet lithography techniques usually suffer from low exposure resolution, failing to meet the requirements for high-resolution nanopattern exposure. Therefore, this invention proposes a micro / nano composite lithography method and system.
[0007] The technical solution adopted in the method of this invention is as follows: A micro / nano composite photolithography method includes the following steps: Spin-coating ultraviolet photoresist onto a conductive substrate; Exposure of nanopatterns on photoresist using conductive nanoprobe exposure technology; The exposed nanopattern area is accurately located using an optical microscopy system, and then the micron pattern is exposed using ultraviolet lithography and accurately aligned with the already exposed nanopattern. Development yields precisely aligned photoresist micro / nano composite patterns. Etching techniques are used to transfer photoresist patterns onto a conductive substrate; Removing excess photoresist yields the micro-nano composite pattern of the conductive substrate.
[0008] Furthermore, the conductive substrate includes a substrate and a conductive layer on the surface of the substrate.
[0009] Furthermore, the ultraviolet photoresist is an ultraviolet negative photoresist.
[0010] Furthermore, the ultraviolet lithography technology employs either maskless projection lithography or scanning ultraviolet exposure technology.
[0011] Furthermore, the etching technology employs either wet etching or dry etching.
[0012] The technical solution adopted by the system of this invention is as follows: The system for implementing the aforementioned micro / nano composite lithography method integrates an ultraviolet lithography device, a nanoprobe lithography device, a sample stage, and a control device. The ultraviolet lithography device includes a white LED, an image sensor, an alignment laser, a photomask, an objective lens, and an exposure controller. The nanoprobe lithography device includes a conductive nanoprobe, a scanning probe base, and a scanning probe controller. The conductive nanoprobe is mounted on the scanning probe base. The exposure controller and the scanning probe controller are respectively connected to the control device.
[0013] Furthermore, the alignment laser is a 650nm laser.
[0014] Furthermore, a high-voltage amplifier is provided between the scanning probe base and the scanning probe controller.
[0015] The solution of the present invention has the following advantages: (1) This invention combines ultraviolet lithography technology and conductive nanoprobe exposure technology, which has both the high resolution of scanning probe lithography technology and the high efficiency of ultraviolet lithography technology.
[0016] (2) The ultraviolet lithography and conductive nanoprobe exposure technologies in the method of the present invention can both work in a normal laboratory environment and do not need to work in a vacuum environment, which greatly reduces the cost of equipment.
[0017] (3) The conductive nanoprobe exposure technology in the method of this invention is a direct writing technology. If the ultraviolet lithography technology adopts a direct writing technology such as maskless projection lithography or scanning ultraviolet exposure technology, then this invention becomes a micro-nano direct writing lithography technology. Therefore, the method of this invention can be used to prepare micro-nano patterns without the need for pre-customized photomasks and other auxiliary tools, which greatly improves the flexibility of pattern preparation.
[0018] (4) The ultraviolet lithography and conductive nanoprobe exposure techniques in the method of the present invention can expose the sample in a non-contact mode, so they will not contaminate the sample surface and improve the quality of micro and nano pattern preparation. On the other hand, since it is a non-contact exposure mode, the method can prepare micro and nano patterns on a variety of non-flat conductive substrates (such as lenses coated with conductive coatings, fiber end faces or sides, etc.), and has a wide range of application scenarios.
[0019] (5) The scanning probe microscope system used in the conductive nanoprobe exposure technology of the present invention usually requires an optical microscopic optical path system to locate the target area on the sample surface and the scanning probe. Therefore, optical exposure equipment such as projection and scanning ultraviolet lithography can be easily integrated into the optical microscopic optical path system of the scanning probe microscope system without making major modifications to the existing equipment. If the ultraviolet lithography equipment is integrated into the scanning probe microscope system, the micro-nano composite lithography on the sample surface can be performed in situ, which greatly improves the accuracy of micro-nano pattern exposure and docking. Attached Figure Description
[0020] Figure 1 This is a flowchart of the micro / nano composite photolithography method of the present invention.
[0021] Figure 2 The process of the micro-nano composite photolithography method of the present invention includes: (a) selectively coating ultraviolet photoresist on a conductive substrate; (b) exposing micro-nano patterns on the ultraviolet photoresist layer using conductive nanoprobe exposure technology and ultraviolet photolithography technology; (c) developing to obtain the micro-nano composite pattern of photoresist; (d) transferring the photoresist pattern to the conductive substrate (conductive layer) using etching technology; and (e) removing excess photoresist to obtain the micro-nano pattern of the conductive material layer.
[0022] Figure 3 This is a flowchart of the method for performing micro-nano composite photolithography on different conductive substrates: (a) ITO glass sheet and (b) gold-plated glass sheet in an embodiment of the present invention.
[0023] Figure 4 shows a scanning electron microscope image of (a) the nano-interdigital electrode pattern, (b) the scanning electron microscope image of the micro-nano composite fabricated interdigital electrode pattern, and (c) the bright field image of the micro-nano composite fabricated interdigital electrode pattern in the embodiments of the present invention.
[0024] Figure 5 This is a schematic diagram of the system structure for realizing the micro-nano composite photolithography method of the present invention. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.
[0026] The flow chart of the micro / nano composite photolithography method proposed in this invention is as follows: Figure 1 As shown, the specific steps include the following: Step 1: Spin-coating UV photoresist onto a conductive substrate. Step 2: Expose nanopatterns on the photoresist using conductive nanoprobe exposure technology. Step 3: Accurately locate the exposed nanopattern area using an optical microscopy system, then use ultraviolet lithography to expose the micron pattern and accurately align it with the already exposed nanopattern. Step 4: Development yields accurately aligned photoresist micro / nano composite patterns. Step 5: Use etching technology to transfer the photoresist pattern onto the conductive substrate (conductive layer). Step 6: Remove excess photoresist to obtain the micro / nano composite pattern of the conductive substrate.
[0027] The order in which nanoprobe lithography and ultraviolet lithography are performed in steps 2 and 3 above can be chosen depending on the specific circumstances; there is no fixed order here. The following section will combine... Figure 2 The specific implementation steps of this invention will be described in detail.
[0028] First, a special ultraviolet photoresist is coated on the surface of the conductive substrate.
[0029] The conductive substrate described herein consists of a substrate and a conductive layer on the surface of the substrate (see...). Figure 2 (a) , wherein the conductive layer is a functional material layer subsequently used to fabricate micro / nano patterns. The substrate and the conductive layer can be made of the same material or different materials, such as depositing a gold film on a glass substrate, depositing a silver film on a silicon substrate, or a bulk conductive silicon wafer. The special ultraviolet photoresist described here is one that can expose micron-sized patterns with ultraviolet light or nano-sized patterns with conductive nanoprobes, such as epoxy resin-based negative photoresists (e.g., SU-8) and phenolic resin-based negative photoresists. The photoresist can be coated using spin-coating or spray-coating methods.
[0030] After coating a conductive substrate with photoresist, high-resolution nanoscale patterns can be exposed on the photoresist surface using conductive nanoprobes, and micrometer-scale patterns can be exposed on the photoresist surface using ultraviolet lithography, thus obtaining micro- and nano-patterns. Figure 2 (b)). The two exposure techniques here are chosen according to the specific situation, and the exposure order can be either conductive nanoprobe exposure followed by ultraviolet exposure, or ultraviolet exposure followed by conductive nanoprobe exposure. After exposure, the exposed areas in the photoresist coating undergo chemical changes. This change manifests in the subsequent development process as different dissolution rates of the exposed and unexposed areas in the photoresist in the developing solution, thus obtaining a micro / nano composite pattern of photoresist after development. Figure 2 (c) Among them, ultraviolet lithography technology uses direct writing techniques such as maskless projection lithography or scanning ultraviolet exposure technology.
[0031] After obtaining the micro-nano composite pattern of the photoresist, the micro-nano composite pattern can be transferred to the underlying conductive material layer through etching technology, which is the micro-nano composite pattern of the desired functional material layer. Figure 2 (d)). The etching techniques described here can be wet etching techniques using liquid chemical reagents, or dry etching techniques such as reactive gases, ion beams or reactive ion beams in a vacuum environment.
[0032] After the pattern is transferred to the conductive material layer, the excess photoresist can be removed using a photoresist stripping process to obtain the micro / nano pattern of the functional material. Figure 2 (e)). The resist removal process described herein can be achieved by dissolving with organic reagents or by dry etching using oxygen plasma.
[0033] The method described in this invention has significant advantages over existing micro / nano lithography techniques, enabling the effective exposure of micro / nano patterns with high resolution and efficiency. Examples of the method's application on two different conductive substrates are given below. Example 1
[0034] A UV photoresist was selectively coated onto a conductive ITO glass substrate. A nanopattern was then exposed on the UV photoresist layer using conductive nanoprobe exposure technology. Next, a larger area of micron-sized patterns was accurately exposed on the UV photoresist layer using contact UV lithography, precisely aligning with the previously formed nanopatterns. After developing the exposed sample, a micro / nano composite pattern of photoresist was obtained. Finally, the photoresist pattern was transferred to the conductive layer of the ITO glass substrate using phosphoric acid wet etching, and excess photoresist was removed using the organic reagent acetone, thus obtaining the ITO micro / nano composite pattern. As shown in Figure 4(a), the interdigitated electrode pattern obtained on the conductive ITO glass substrate has a finger spacing of 100 nm, a period of 200 nm, and a busbar width of 3 μm. Example 2
[0035] Ultraviolet photoresist was selectively coated onto a gold-plated conductive silicon wafer. A large-area micron pattern was then exposed on the photoresist layer using projection ultraviolet lithography. Next, a nano-pattern was exposed on the photoresist layer using conductive nanoprobe exposure technology, precisely aligning with the previously formed micron pattern. After developing the exposed sample, a micro / nano composite pattern of photoresist was obtained. Finally, the photoresist pattern was transferred to a conductive gold thin layer using ion beam dry etching, and excess photoresist was removed using oxygen plasma, resulting in a gold micro / nano composite pattern. As shown in Figure 4, (b) is the nano-interdigitated electrode pattern obtained after exposure on the photoresist using conductive nanoprobe exposure technology, with a finger spacing of 100 nm and a period of 200 nm, designed to verify the stability of the nano-pattern processing; (c) is the image (50x) of the final interdigitated electrode pattern obtained through the micro / nano composite lithography method under a bright-field Olympus microscope, where the finger spacing is 100 nm, the period is 200 nm, and the busbar linewidth is 3 μm. Example 3
[0036] This embodiment provides a system for implementing the above-described micro / nano composite photolithography method, such as... Figure 5 As shown, the system integrates an ultraviolet lithography device, a nanoprobe lithography device, a sample stage, and a control computer. The ultraviolet lithography device utilizes a white LED and a CCD image sensor for observation, and a 650nm alignment laser to assist in aligning the sample markings. The ultraviolet LED, through a computer-controlled exposure controller and photomask, exposes the sample in a patterned manner. The shape and position of the photomask are customizable. The nanoprobe lithography device includes conductive nanoprobes, a scanning probe base, and a scanning probe controller. Because an external voltage is required, the device's own voltage sometimes fails to reach the exposure threshold; therefore, a high-voltage amplifier is sometimes connected between the base and the controller. The conductive nanoprobes are mounted on the scanning probe base for subsequent scanning probe lithography.
[0037] The implementation process of this system takes nano-probe photolithography followed by ultraviolet lithography as an example. Specifically, it includes: fixing the sample substrate after spin-coating photoresist on the xyz triaxial displacement stage, accurately positioning it using the pre-made marks on the sample, and then performing scanning probe photolithography; after completion, removing the scanning probe base, aligning the objective lens with the sample mark, and performing ultraviolet lithography; finally, the preparation of the micro-nano composite patterned sample is completed through the above steps 4-6.
[0038] Obviously, the above embodiments are merely some, not all, of the embodiments of the present invention. The above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without inventive effort, that is, all modifications, equivalent substitutions, and improvements made within the spirit and principle of this application, fall within the scope of protection claimed by the present invention.
Claims
1. A micro / nano composite photolithography method, characterized in that, The method includes the following steps: Spin-coating ultraviolet photoresist onto a conductive substrate; Exposure of nanopatterns on photoresist using conductive nanoprobe exposure technology; The exposed nanopattern area is accurately located using an optical microscopy system, and then the micron pattern is exposed using ultraviolet lithography and accurately aligned with the already exposed nanopattern. Development yields precisely aligned photoresist micro / nano composite patterns. Etching techniques are used to transfer photoresist patterns onto a conductive substrate; Removing excess photoresist yields the micro-nano composite pattern of the conductive substrate.
2. The micro / nano composite photolithography method according to claim 1, characterized in that, The conductive substrate includes a substrate and a conductive layer on the surface of the substrate.
3. The micro / nano composite photolithography method according to claim 1, characterized in that, The ultraviolet photoresist used is an ultraviolet negative photoresist.
4. The micro / nano composite photolithography method according to claim 1, characterized in that, The ultraviolet lithography technology mentioned above uses either maskless projection lithography or scanning ultraviolet exposure technology.
5. The micro / nano composite photolithography method according to claim 1, characterized in that, The etching technology used is either wet etching or dry etching.
6. A system for implementing the micro / nano composite photolithography method as described in claim 1, characterized in that, The system is integrated with an ultraviolet lithography device, a nanoprobe lithography device, a sample stage, and a control device. The ultraviolet lithography device includes a white LED, an image sensor, an alignment laser, a photomask, an objective lens, and an exposure controller. The nanoprobe lithography device includes a conductive nanoprobe, a scanning probe base, and a scanning probe controller. The conductive nanoprobe is mounted on the scanning probe base. The exposure controller and the scanning probe controller are respectively connected to the control device.
7. The system according to claim 6, characterized in that, The alignment laser used is a 650nm laser.
8. The system according to claim 6, characterized in that, A high-voltage amplifier is provided between the scanning probe base and the scanning probe controller.