Nanometer photoresist dry film form, preparation method and use method thereof

Abstract

The invention provides a nano photoresist dry film form, a preparation method and a use method thereof. The dry film form of the nano photoresist comprises a sandwich structure formed by three layers of materials: the middle layer comprises PVA (Polyvinyl Alcohol) water-based photoresist or PMMA (Polymethyl Methacrylate) photoresist, the upper layer is covered with a release film as a protective layer, and the lower layer is a PDMS (Polydimethylsiloxane) carrier for supporting and transferring a photoresist film; the middle layer is a commercial functional photoresist, the upper side and the lower side of the middle layer are covered with a PVA water-based photoresist and a pure PVA water-based film respectively to serve as protective layers, the core functional layer is isolated and protected against lossless transfer, and the outermost layer is a release film on the top and a PDMS carrier on the bottom in sequence to support and achieve overall transfer of the photoresist film. According to the nano photoresist dry film form, the preparation method and the use method thereof, provided by the invention, the pattern resolution, the structural fidelity and the process compatibility can be improved, and the requirements on high-precision, low-cost and high-throughput micro-nano processing in the fields of microelectronic manufacturing, micro-nano optical element processing, micro-fluidic chips and the like are met.

Description

Technical Field

[0001] This invention relates to the field of micro-nano manufacturing, and in particular provides a method for the preparation and use of a nano-photoresist dry film. Background Technology

[0002] Currently, photoresist, as a core functional material in photolithography, is crucial for ensuring pattern transfer accuracy and process stability in micro- and nano-manufacturing. Its performance directly determines the resolution, linewidth control capability, and compatibility with subsequent processes of microstructures. In integrated circuits, packaging, microelectronic devices, microelectromechanical systems (MEMS), and emerging flexible electronics, the technological level of photoresist has become an important indicator of manufacturing capabilities and industrial competitiveness. Among them, dry film photoresist, with its advantages of simple processing, low waste discharge, and applicability to both rigid and flexible substrates, is widely used in printed circuit boards (PCBs), semiconductor packaging, display devices, and advanced sensors.

[0003] Traditional dry film photoresists typically exist in sandwich-style roll or sheet form, where the photoresist layer is sandwiched between a polyester protective film (PET) and a polyethylene release film (PE), with a common thickness between 25–100 μm. In application, the dry film photoresist is first uniformly bonded to the substrate surface under specific temperature and pressure using a hot roller press; then, ultraviolet light is used to selectively expose the dry film through a mask; next, a developer is used to remove uncured or unexposed areas, revealing the desired microstructure pattern; finally, post-baking, etching, electroplating, or photoresist stripping is performed according to process requirements to complete the fabrication of the fine pattern. The minimum precision of traditional dry film photoresists can only reach 5 μm. However, with the rapid expansion of downstream applications, the technological limitations of traditional dry film photoresists are becoming increasingly apparent.

[0004] As industries such as PCB, display, advanced packaging, and semiconductors continue to evolve towards higher precision, smaller size, and more complex functions, the existing properties of photoresist dry films, such as thickness, precision, and photosensitivity, are no longer suitable for the requirements of high-end electronic product manufacturing. Especially in terms of cost and efficiency, the market demand for dry films with higher cost-effectiveness, higher precision, and thinner thickness is becoming increasingly urgent. Patent CN108037634B proposes some high-precision (35 μm), low-thickness (25 μm) dry film photoresists, and patent CN111965958A proposes other high-precision (30 μm), low-thickness (35 μm) dry film photoresists, but the thickness is far less than expected (unable to achieve nanometer thickness), making it difficult to achieve nanometer precision. Summary of the Invention

[0005] Based on this, the present invention provides a morphology, preparation, and application method of a nano-photoresist dry film. This aims to improve pattern resolution, structural fidelity, and process compatibility, simplifying the complex processes of traditional spin coating and multiple photolithography steps. By introducing a transferable photoresist, the present invention successfully reduces the thickness of traditional micron-level (approximately 25 μm) dry film photoresist to nanometer-level (approximately 200 nm) thickness, and utilizes this nano-photoresist dry film to achieve highly consistent fabrication of wafer-level micro / nano structures, further breaking through to the stable construction of nanometer-resolution structures, providing an efficient and feasible technical path for high-precision, large-area photolithography.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a nano-photoresist dry film morphology, which is a sandwich structure composed of three layers: the middle layer includes PVA aqueous photoresist or PMMA photoresist, the upper layer is covered with a release film as a protective layer, and the lower layer is a PDMS carrier that supports and transfers the photoresist film; or it is a multilayer film structure composed of five layers: the middle layer is a commercially available functional photoresist, and its upper and lower sides are respectively covered with PVA aqueous photoresist and pure PVA aqueous film as protective layers to isolate and protect the core functional layer from damage during transfer, and the outermost layers are, in sequence, a release film at the top and a PDMS carrier at the bottom, which support and realize the overall transfer of the photoresist film.

[0007] To achieve the above objectives, in a second aspect, the present invention provides a process for preparing a nano-photoresist dry film, used to manufacture the aforementioned nano-photoresist, comprising the following steps: S110. Clean the substrate with deionized water using ultrasonic cleaning and dry it with nitrogen gas. S120. Apply adhesive to achieve uniform, impurity-free, near-zero adhesion of a large-area nano-PVA photoresist film. S130. After the photoresist is applied, place it on a hot plate to heat it and slowly remove excess solvent from the photoresist; S140. If a multilayer film structure is required, a layer of commercial functional photoresist is spin-coated and baked to cure, followed by a layer of PVA aqueous solution spin-coated and dried. S150. Slowly attach the PDMS stamp to the photoresist surface and peel the photoresist off the substrate without damage. S160. Conformally bond the protective layer to the photoresist film to construct a sandwich structure or a multilayer film structure.

[0008] Furthermore, the substrate comprises a silicon wafer and / or silicon dioxide.

[0009] Furthermore, the coating method includes at least one of spin coating, dip coating, or spray coating; the photoresist is a PVA water-based photoresist.

[0010] Furthermore, the protective layer comprises at least one of polyethylene terephthalate (PET) film, polyimide (PI) film, or polyethylene film.

[0011] Furthermore, the protective layer is bonded by rolling a roller or scraper from the center to the edge to directly bond it, eliminating air bubbles.

[0012] Furthermore, the protective layer is bonded by heat coating, which achieves semi-permanent bonding between materials through heating and pressurization.

[0013] To achieve the above objectives, in a third aspect, the present invention provides a method for using a nano-photoresist dry film, wherein the method uses the aforementioned nano-photoresist and includes the following steps: S210. Peel off the protective layer of the sandwich structure / multilayer nanophotoresist dry film; S220. PDMS and photoresist are bonded to the mask without bubbles or gaps; S230. Exposure using a contact ultraviolet lithography machine; S240. The photoresist is released non-destructively onto the acceptor on a hot plate; S250. If it is a multilayer film structure, the PVA solution protective layer needs to be dissolved with deionized water before development; S260. Immersion development is used to develop the photoresist released onto the silicon wafer in a developing solution.

[0014] Furthermore, the receptor includes at least one of silicon wafer, silicon dioxide, flexible substrate, etc.

[0015] Furthermore, the time for dissolving the PVA solution in deionized water is 10 seconds.

[0016] The technical advantages of the nanophotoresist dry film morphology, preparation method and application method provided by the present invention are at least reflected in: Firstly, the provided sandwich-structured nano-photoresist dry film, with the photoresist layer sandwiched between two protective films, has excellent stripping performance and is mainly suitable for stripping processes. It can achieve high-resolution, low-defect-rate pattern transfer during metal deposition, etching, and other processes. Secondly, the provided multilayer film structure nanophotoresist dry film integrates commercially available functional photoresist and auxiliary layer materials, enabling multifunctional integration in a single transfer process. It is particularly suitable for the fabrication of high aspect ratio micro / nano structures and subsequent etching processes. Thirdly, two different forms of nano-photoresist dry films are achieved through the development of transferable photoresist materials, large-area uniform coating technology, film transfer process, and matching conformal contact lithography process. This not only takes into account pattern resolution, structural fidelity, and process compatibility, but also simplifies the complex process of traditional spin coating and multiple lithography. It can meet the urgent needs of microelectronics manufacturing, micro-nano optical component processing, and microfluidic chip manufacturing for high-precision, low-cost, and high-throughput micro-nano processing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The specific embodiment is a nanometer photoresist dry film sandwich structure.

[0019] Figure 2 The specific embodiment is a multilayer film structure of nanometer photoresist dry film.

[0020] Figure 3 The specific embodiment 1 describes the fabrication process of a nanometer photoresist dry film multilayer film.

[0021] Figure 4 The following is a specific embodiment of the process for using a nanometer photoresist dry film multilayer film.

[0022] Figure 5 This is a specific embodiment 1, a large-area nano-photoresist dry film.

[0023] Figure 6 The micro-nano cross-scale structure obtained by exposure of dry film in Specific Implementation Example 1 is shown.

[0024] Figure 7 The nanostructure obtained by exposure of a dry film in Specific Example 2 is shown. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The rapid rise of emerging fields such as flexible electronics and solar cells requires comprehensive innovation and transformation, or even redefinition, of dry film photoresists in terms of their working form, process, and application methods to meet the specific needs of these industries for photoresists. Therefore, promoting independent research and development and technological innovation of dry film photoresists, enhancing their adaptability in different application scenarios, and improving technological reserves have become key tasks for technological development.

[0028] like Figure 1 and Figure 2 As shown, in a first aspect, the present invention provides a nano-photoresist dry film morphology: The structure comprises a sandwich of three layers: the middle layer consists of PVA aqueous photoresist or PMMA photoresist, the upper layer is covered with a release film as a protective layer, and the lower layer is a PDMS carrier that supports and transfers the photoresist film; or The multilayer film structure consists of five layers: the middle layer is a commercially available functional photoresist, with PVA aqueous photoresist and pure PVA aqueous film covering the top and bottom sides as protective layers to isolate and protect the core functional layer for lossless transfer; the outermost layers are a release film on top and a PDMS carrier on the bottom, which support and enable the overall transfer of the photoresist film.

[0029] like Figure 3 As shown, this invention provides a process for preparing a dry film of nano-photoresist, used to manufacture the aforementioned nano-photoresist, comprising the following steps: S110. Clean the substrate with deionized water using ultrasonic cleaning for 5 minutes and then dry it with nitrogen gas. S120. Apply adhesive to achieve uniform, impurity-free, near-zero adhesion of a large-area nano-PVA photoresist film. S130. After the photoresist is applied, place it on a hot plate and heat it at 80 ℃ for 1 min to slowly remove excess solvent from the photoresist. S140. If a multilayer film structure is required, a layer of commercial functional photoresist is spin-coated and baked to cure, followed by a layer of PVA aqueous solution spin-coated and dried. S150. Slowly attach the PDMS stamp to the photoresist surface at a speed of 5 mm / s, and peel the photoresist off the substrate without damage. S160. Conformally bond the protective layer to the photoresist film to construct a sandwich structure or a multilayer film structure.

[0030] like Figure 4 The present invention provides a method for using a nano-photoresist dry film, wherein the method uses the aforementioned nano-photoresist and includes the following steps: S210. Peel off the protective layer of the sandwich structure / multilayer nanophotoresist dry film; S220. PDMS and photoresist are bonded to the mask without bubbles or gaps; S230. Expose for 5-10 seconds using a contact ultraviolet lithography machine; S240. The photoresist is released onto the acceptor without damage on a hot plate at 80°C; S250. If it is a multilayer film structure, the PVA solution protective layer needs to be dissolved with deionized water before development; S260. Immersion development is used to develop the photoresist released onto the silicon wafer in the developer solution for 5-15 seconds.

[0031] The nano-photoresist dry film morphology, preparation and application methods provided by this invention can improve pattern resolution, structural fidelity and process compatibility, and simplify the complex process of traditional spin coating and multiple photolithography.

[0032] The following detailed description is provided with reference to specific embodiments: Example 1

[0033] like Figure 1 As shown, the nano-photoresist dry film morphology package provided in this embodiment has a sandwich structure, consisting of three layers: the middle layer is PVA aqueous photoresist, the upper layer is covered with a release film as a protective layer, and the lower layer is a PDMS carrier used to support and transfer the photoresist film.

[0034] The above-mentioned process for preparing nano-photoresist dry films includes the following steps: Step 1: Substrate cleaning; ultrasonically clean the substrate with deionized water for 5 minutes and dry it with nitrogen gas. The substrate includes silicon wafers and silicon dioxide.

[0035] Step 2: Coating; Using spin coating, at low speed (500 r / min, 30 s) and high speed (3000 r / min, 60 s), a uniform, impurity-free, near-zero adhesion large-area nano PVA photoresist film (thickness 300 nm) is obtained.

[0036] Step 3: Pre-baking; After the photoresist is applied, place it on a hot plate and heat it at 80 ℃ for 1 min to slowly remove excess solvent from the photoresist.

[0037] Step 4: Peeling; Slowly attach the PDMS stamp to the photoresist surface at a speed of 5 mm / s, and peel the photoresist off the substrate without damage.

[0038] Step 5: Construct the sandwich structure; conformally bond the PET protective layer and the photoresist film directly to construct the sandwich structure.

[0039] Figure 5 This invention demonstrates the preparation of a large-area unprotected nanofilm, from which... Figure 5 It can be seen that the prepared large-area nano-dry membrane has excellent membrane surface uniformity. During use, the above-mentioned nano-photoresist dry film is used in the following ways: Step 1: Peel off the protective layer; peel off the PET protective layer of the sandwich-structured nano-dry film.

[0040] Step 2: Laying the mask; use a roller press to lay the PDMS and photoresist onto the mask without air bubbles.

[0041] Step 3: Exposure; Expose for 5 seconds using a contact ultraviolet lithography machine.

[0042] Step 4: Release; release the photoresist onto the silicon wafer without damage on a hot plate at 80°C.

[0043] Step 5: Development; Immersion development is used to develop the photoresist released onto the silicon wafer in deionized water developer for 7 seconds.

[0044] Figure 6 To further verify the pattern transfer effect of the micro-nano cross-scale structure obtained by exposure using dry film, the micro-nano cross-scale structure is arranged in a regular manner and has good uniformity.

[0045] Example 1 demonstrates how combining large-area nano-dry film with perfectly conformal contact lithography can stably achieve high-fidelity pattern transfer of large-area micro / nano structures. This process not only simplifies the complex steps in traditional dry film lithography but also effectively overcomes its technical bottlenecks in terms of resolution, substrate type compatibility, and film area. Example 2

[0046] The nano-photoresist dry film preparation process provided in this embodiment includes: Step 1: Substrate cleaning; ultrasonically clean the substrate with deionized water for 5 minutes and then dry it with nitrogen gas.

[0047] Step 2: Coating; Using spin coating, at low speed (500 r / min, 30 s) and high speed (4000 r / min, 60 s), a uniform, impurity-free, near-zero adhesion large-area nano PMMA photoresist film (thickness 200 nm) is obtained.

[0048] Step 3: Pre-baking; After the photoresist is applied, place it on a hot plate and heat at 80 ℃ for 2 minutes to slowly remove excess solvent from the photoresist.

[0049] Step 4: Peeling; Slowly attach the PDMS stamp to the photoresist surface at a speed of 5 mm / s, and peel the photoresist off the substrate without damage.

[0050] Step 5: Construct the sandwich structure; thermally conformally bond the PI protective layer and the photoresist film to construct the sandwich structure.

[0051] The methods for using the prepared nano-photoresist dry film include: Step 1: Peel off the protective layer; peel off the protective layer PI of the sandwich-structured nano-dry film.

[0052] Step 2: Laying the mask; use a roller press to lay the PDMS and photoresist onto the mask without air bubbles.

[0053] Step 3: Exposure; Expose for 25 seconds using a 172 nm short-wavelength lithography device.

[0054] Step 4: Release; release the photoresist onto the silicon wafer without damage on a hot plate at 80°C.

[0055] Step 5: Development; Immersion development is used to develop the photoresist released onto the silicon wafer in PMMA developer for 20 seconds.

[0056] The manufactured nano-photoresist dry film is used in the field of microelectronics manufacturing, such as solid thin film photoresist materials used in integrated circuits, advanced packaging, and micro-nano manufacturing. The film is pre-made with nano-thickness and uniformity through precision coating technology, and is used for the transfer and replication of nanoscale patterns. Example 3

[0057] The nano-photoresist dry film preparation process provided in this embodiment includes: Step 1: Substrate cleaning; ultrasonically clean the substrate with deionized water for 5 minutes and then dry it with nitrogen gas.

[0058] Step 2: Coating; Using spin coating, at low speed (500 r / min, 30 s) and high speed (12000 r / min, 60 s), a uniform, impurity-free, near-zero adhesion large-area nano PVA photoresist film (thickness 200 nm) is obtained.

[0059] Step 3: Pre-baking; After the photoresist is applied, place it on a hot plate and heat it at 80 ℃ for 1 min to slowly remove excess solvent from the photoresist.

[0060] Step 4: Peeling; Slowly attach the PDMS stamp to the photoresist surface at a speed of 5 mm / s, and peel the photoresist off the substrate without damage.

[0061] Step 5: Construct the sandwich structure; thermally conformally bond the PE protective layer and the photoresist film to construct the sandwich structure.

[0062] The methods for using the prepared nano-photoresist dry film include: Step 1: Peel off the protective layer; peel off the protective PE layer of the sandwich-structured nano-dry film.

[0063] Step 2: Laying the mask; use a roller press to lay the PDMS and photoresist onto the mask without air bubbles.

[0064] Step 3: Exposure; Expose for 4 seconds using a contact ultraviolet lithography machine.

[0065] Step 4: Release; release the photoresist onto the silicon dioxide without damage on a hot plate at 80°C.

[0066] Step 5: Development; Immersion development is used to develop the photoresist released onto the silicon dioxide in the developing solution for 6 seconds.

[0067] The sandwich-structured nano-photoresist dry film provided in this embodiment has a photoresist layer sandwiched between two protective films, exhibiting excellent stripping performance. It is mainly suitable for stripping processes and can achieve high-resolution, low-defect-rate pattern transfer during metal deposition, etching, and other processes. Example 4

[0068] This embodiment provides a process for preparing a nano-photoresist dry film, including the following steps: Step 1: Substrate cleaning; ultrasonically clean the substrate with deionized water for 5 minutes and then dry it with nitrogen gas.

[0069] Step 2: Coating; Using spin coating, at low speed (500 r / min, 30 s) and high speed (12000 r / min, 60 s), a uniform, impurity-free, near-zero adhesion large-area nano PVA photoresist film (thickness 200 nm) is obtained.

[0070] Step 3: Pre-baking; After the photoresist is applied, place it on a hot plate and heat it at 80 ℃ for 1 min to slowly remove excess solvent from the photoresist.

[0071] Step 4: Peeling; Slowly and bubble-free, attach the PDMS stamp to the photoresist surface and peel the photoresist off the substrate without damage.

[0072] Step 5: Construct the sandwich structure; thermally conformally bond the PET protective layer and the photoresist film to construct the sandwich structure.

[0073] The methods for using the prepared nano-photoresist dry film include: Step 1: Peel off the protective layer; peel off the PET protective layer of the sandwich-structured nano-dry film.

[0074] Step 2: Laying the mask; use a roller press to lay the PDMS and photoresist onto the mask without air bubbles.

[0075] Step 3: Exposure; Expose for 4 seconds using a contact ultraviolet lithography machine.

[0076] Step 4: Release; release the photoresist non-destructively onto the polyurethane (TPU) flexible substrate on a hot plate at 80°C.

[0077] Step 5: Development; Immersion development is used, and the photoresist released onto the TPU is developed in deionized water developer for 6 seconds.

[0078] Based on the large-area nano-dry film manufactured in this embodiment, the photolithography process not only takes into account high resolution and large-area processing capabilities, but also has advantages such as low cost and strong process compatibility, providing stable and reliable technical support for applications such as flexible electronics, micro-nano optical components, and sensor arrays.

[0079] Nanophotoresist dry films are achieved through the development of transferable photoresist materials, large-area uniform coating technology, film transfer process, and matching conformal contact lithography process. This not only takes into account pattern resolution, structural fidelity, and process compatibility, but also simplifies the complex process of traditional spin coating and multiple lithography. It can meet the urgent needs of microelectronics manufacturing, micro-nano optical component processing, and microfluidic chip manufacturing for high-precision, low-cost, and high-throughput micro-nano processing.

[0080] This document provides a detailed description and uses specific examples to illustrate the principles and implementation methods of the present invention. The above embodiments are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

[0081] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

Claims

1. A nano-photoresist dry film morphology, characterized in that: It is a sandwich structure composed of three layers: the middle layer includes PVA aqueous photoresist or PMMA photoresist, the upper layer is covered with a release film as a protective layer, and the lower layer is a PDMS carrier that supports and transfers the photoresist film; Alternatively, it can be a multilayer film structure composed of five materials: the middle layer is a commercial functional photoresist, and the top and bottom sides are covered with PVA aqueous photoresist and pure PVA aqueous film as protective layers to isolate and protect the core functional layer for lossless transfer. The outermost layers are the top release film and the bottom PDMS carrier, which support and realize the overall transfer of the photoresist film.

2. A process for preparing a dry film of nanophotoresist, used to manufacture the nanophotoresist according to claim 1, characterized in that the steps include... include: S110. Clean the substrate with deionized water using ultrasonic cleaning and dry it with nitrogen gas. S120. Apply adhesive to achieve uniform, impurity-free, near-zero adhesion of a large-area nano-PVA photoresist film. S130. After the photoresist is applied, place it on a hot plate to heat it and slowly remove excess solvent from the photoresist; S140. If a multilayer film structure is required, a layer of commercial functional photoresist is spin-coated and baked to cure, followed by a layer of PVA aqueous solution spin-coated and dried. S150. Slowly adhere the PDMS stamp to the photoresist surface and peel the photoresist off the substrate without damage. S160. Conformally bond the protective layer to the photoresist film to construct a sandwich structure or a multilayer film structure.

3. The nano-photoresist dry film preparation process according to claim 2, characterized in that: The substrate includes silicon wafers and / or silicon dioxide.

4. The nano-photoresist dry film preparation process according to claim 2, characterized in that: The coating method includes at least one of spin coating, dip coating, or spray coating; the photoresist is a PVA water-based photoresist.

5. The nano-photoresist dry film preparation process according to claim 2, characterized in that: The protective layer includes at least one of polyethylene terephthalate (PET) film, polyimide (PI) film, or polyethylene film.

6. The nano-photoresist dry film preparation process according to claim 2, characterized in that: The protective layer is bonded by rolling a roller or scraper from the center to the edge to directly bond it, eliminating air bubbles.

7. The nano-photoresist dry film preparation process according to claim 2, characterized in that: The protective layer is bonded by heat coating, which achieves semi-permanent bonding between materials through heating and pressurization.

8. A method for using a nano-photoresist dry film, using the nano-photoresist according to any one of claims 1 to 7, characterized in that the step... include: S210. Peel off the protective layer of the sandwich structure / multilayer nanophotoresist dry film; S220. PDMS and photoresist are bonded to the mask without bubbles or gaps; S230. Exposure using a contact ultraviolet lithography machine; S240. The photoresist is released non-destructively onto the acceptor on a hot plate; S250. If it is a multilayer film structure, the PVA solution protective layer needs to be dissolved with deionized water before development; S260. Immersion development is used to develop the photoresist released onto the silicon wafer in the developer solution for 5-15 seconds.

9. The method of using the nano-photoresist dry film according to claim 1, characterized in that: The receptor includes at least one of silicon wafers, silicon dioxide, flexible substrates, etc.

10. The method of using the nano-photoresist dry film according to claim 1, characterized in that: The time for dissolving the PVA solution in deionized water is 10 seconds.

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