A process for electroforming a Ni / Cu / Ni stacked alternating structure optical component

Abstract

The application discloses a process method for electroforming Ni / Cu / Ni alternating structure optical component, and belongs to the field of electrochemical additive manufacturing. The method forms a nickel carrier layer, a copper functional layer and bright nickel reflecting layer distributed according to a predetermined grating pattern on a conductive plane substrate in sequence; after the electroforming of each metal layer is completed and the glue mold is removed, the surface of the copper functional layer exposed without being covered by the bright nickel reflecting layer is blackened to form a blackened copper light-absorbing layer, so that the light-absorbing area and the reflecting area are alternately distributed on the same working surface. The application forms different functional layers according to the unified positioning reference through the multi-level overlaying with spatial corresponding relationship, realizes the integrated manufacturing of the longitudinal multi-material alternating structure and the horizontal optical function partition, and is beneficial to improving the structural integration, the functional area position consistency and the structural stability under the complex environment of the component.

Description

Technical Field

[0001] This invention relates to the field of electrochemical additive manufacturing technology, specifically to a process method for electroforming Ni / Cu / Ni alternating layer optical components. Technical Background

[0002] As precision optical measurement devices evolve towards miniaturization, high precision, and high reliability, higher demands are placed on the structural dimensions, pattern accuracy, optical performance, and environmental adaptability of their optical functional components. These optical functional components typically need to form functional regions with different optical response characteristics within a limited working surface according to a predetermined pattern. Different regions generate differentiated reflections or absorptions of incident light to achieve the modulation and recognition of optical signals. Therefore, in addition to requiring significant differences in optical response between different functional regions, it is also necessary to consider the miniaturization of the components, the positional accuracy between different functional regions, and the structural stability under complex working environments.

[0003] Currently, the manufacturing processes for such precision optical functional components mainly include glass substrate coating photolithography, metal sheet photochemical processing, electroforming replication, and multilayer metal electrodeposition. These processes each have advantages in areas such as micro-patterning, metal structure manufacturing, and multi-material stacking. However, for optical components that simultaneously require compact structures, integration of multiple optical functions, precise positioning of functional areas, and high environmental adaptability, each process still has room for improvement to varying degrees.

[0004] Patent CN113860757B discloses a method for manufacturing a glass code disk. This method involves steps such as chromium plating on a glass substrate, coating with photoresist, exposure and development, and etching the chromium plating layer to create precision optical patterns. The advantage of this method is that it achieves an accuracy of 1μm, making it suitable for fabricating high-resolution optical patterns. However, its disadvantages include: the optical functional patterns are formed on the surface of the glass substrate, requiring further connection and positioning between the glass optical components and the mechanical mounting structure under certain application conditions; and the structural reliability of the glass material is limited under complex mechanical environments such as impact and vibration.

[0005] The patent with publication number CN216647049U uses a metal substrate to form a thin metal sheet structure with precise optical patterns through chemical etching. Its advantages are that the all-metal structure has better mechanical strength and impact resistance compared to glass. However, its shortcomings are that there is still room for further optimization in balancing the size of the micro-patterns, structural integrity, and integration of different optical functional areas.

[0006] The patent with publication number CN1495003A uses electroforming to form metal components with precise surface structures. Its advantages include high electroforming replication accuracy, precisely replicating the micro-nano structural features of the core mold surface. However, its shortcomings lie in the fact that traditional electroforming replication typically uses a single metal material to form an integral structure, mainly addressing the problem of precisely replicating the component's geometric structure. When the same component's working surface needs to simultaneously form functional areas with different light absorption and reflective properties, relying solely on a single metal material and geometric structure makes it difficult to achieve the integrated materialization of different optical functions.

[0007] Existing technologies also include electrodeposition methods for preparing multilayer dissimilar metal materials. For example, existing technologies for preparing stacked electrolytic foils can sequentially deposit Cu and Ni layers on a support surface, thereby forming a stacked metal structure composed of different metal materials. These technologies demonstrate that different metal materials can form a longitudinally multi-material stacked system through continuous electrodeposition. However, these technologies primarily focus on the continuous deposition of each metal layer along its thickness and the control of material properties. The different metal layers are typically distributed in a monolithic or continuous layered manner, and are not designed to address the issue of achieving spatially selective distribution of different functional materials in optical components according to predetermined micro-patterns.

[0008] In summary, while existing manufacturing technologies can achieve high-precision optical pattern processing, metal component manufacturing, or multi-material stacking, the following problems still exist in optical functional components that require miniaturization, high positional accuracy, environmental reliability, and high optical signal contrast: First, the mechanical load-bearing structure and different optical functional structures often need to be formed through different processes or combined from multiple independent functional components, increasing structural space and functional interfaces, which is not conducive to further miniaturization and high integration of components; second, after multiple independent processing or subsequent assembly, different material layers and different optical functional areas are prone to forming multi-level positional error chains, which is not conducive to ensuring a stable spatial correspondence between functional areas; third, existing single-material replication or continuous multi-layer deposition methods make it difficult to simultaneously form light-absorbing and reflective areas with significant differences in optical performance on the same working surface. Therefore, how to achieve a high degree of integration of structural load-bearing, different material functional layers, and light-absorbing and reflective optical functional areas while ensuring precision pattern manufacturing capabilities, and taking into account the positional accuracy and environmental adaptability of components, remains a problem that needs to be further solved in the manufacturing technology of such optical functional components. Summary of the Invention

[0009] To address the challenges of precise spatial partitioning of functional layers made of different materials according to a unified positional reference in existing optical component manufacturing processes, and the relative positional errors that easily arise during the assembly of separately manufactured functional components, this invention provides a process for electroforming an alternating Ni / Cu / Ni stacked optical component. This method combines overlay and electroforming techniques, allowing the nickel carrier layer, copper functional layer, and bright nickel layer to be formed sequentially according to a unified photolithographic positioning reference. After all metal layers are electroformed, the exposed copper functional layer, not covered by the bright nickel layer, undergoes a blackening treatment. This creates alternating blackened copper light-absorbing areas and bright nickel reflective areas with a predetermined grating pattern on the working surface of the same metal component, reducing relative positional errors caused by subsequent bonding or assembly of independent functional components. This achieves integrated manufacturing of the vertically alternating multi-material stacked structure and the horizontal optical functional partitioning.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows.

[0011] A process for electroforming an optical component with an alternating Ni / Cu / Ni multilayer structure, comprising the following steps performed in sequence: Step S1: Apply a positive photoresist with a thickness of 5μm-100μm evenly to the conductive planar substrate that has undergone standard pretreatment, and perform standard pre-baking and standing treatments as required. Step S2: Fabricate a photoresist pattern layer I on the photoresist using a photolithography process; Step S3: Using the assembly including the conductive planar substrate and the molded pattern layer I made in step S2 as the cathode, electroform a conventional metallic nickel layer to form a nickel carrier layer, which serves as the bottom support structure of the stacked alternating structure optical component; Step S4: Perform a finishing process on the nickel carrier layer and the mold pattern layer prepared in step S3. Using the positioning marks formed by photolithography in the previous step as the overlay reference, form a mold pattern layer II with the same structural features but a greater thickness on the surface of the mold pattern layer I; the thickness of the mold pattern layer II is 100μm~200μm. Step S5: Using the combined structure of conductive planar substrate, nickel carrier layer and mold pattern layer II as cathode, copper ions are deposited in the electroforming area defined by mold pattern layer II to form a copper functional layer on the surface of nickel carrier layer, which serves as the intermediate structural layer of the stacked alternating structure optical component. Step S6: Perform a finishing process on the copper functional layer and the molded pattern layer II made in step S5. Using the positioning marks formed by photolithography in the previous step as the overlay reference, form a molded pattern layer III with a thickness of 20μm~50μm and specific grating stripes on the surface of the molded pattern layer II. Step S7: Using the combined structure of the conductive planar substrate, nickel carrier layer, copper functional layer and molded pattern layer III obtained in step S6 as the cathode, a bright nickel layer is deposited in the electroforming area defined by the molded pattern layer III as the reflective layer of the stacked alternating structure optical component. Step S8: After the nickel carrier layer, copper functional layer and bright nickel layer are electroformed, mold pattern layer I, mold pattern layer II and mold pattern layer III are removed to expose the surface of the copper functional layer that is not covered by the bright nickel layer; then the copper functional layer that is not covered by the bright nickel layer is blackened to form a blackened copper layer on its surface, which serves as the light-absorbing layer of the stacked alternating structure optical component; Step S9: Peel the metal components formed above, including the nickel carrier layer, copper functional layer, blackened copper layer, and bright nickel layer, from the conductive planar substrate to obtain an optical component with an alternating Ni / Cu / Ni stack structure.

[0012] Preferably, the light-absorbing layer has an absorbency of ≥90%.

[0013] Preferably, the reflectivity of the reflective layer is ≥70%.

[0014] Compared with the prior art, the main advantages of this invention are as follows: (1) It can obtain compact and highly integrated micro-optical functional components.

[0015] This invention employs a combination of multi-stage high-precision photolithography and precision mask electroforming to sequentially form a nickel carrier layer, a copper functional layer, and a bright nickel layer on the same substrate. Subsequent blackening treatment creates a light-absorbing layer in the exposed copper areas, thus integrating mechanical load-bearing, light-absorbing, and reflective functions into a single metal component. Compared to separately fabricating the carrier, light-absorbing, and reflective components and then bonding or assembling them, this invention reduces independent functional parts, connection interfaces, and corresponding installation space. It allows the light-absorbing and reflective areas to be directly formed on the same working surface, achieving integration of structural forming and optical functional forming. This improves the structural compactness and functional integration of the component, meeting the miniaturization and integration needs of precision optical devices.

[0016] (2) It can obtain optical functional components with high precision and stronger environmental adaptability.

[0017] This invention employs a multi-level photolithography overlay process with positional inheritance, allowing the nickel carrier layer, copper functional layer, and bright nickel layer to be formed sequentially according to a unified positioning benchmark. This directly establishes the spatial relationships between functional layers and between light-absorbing and reflective areas during electroforming, reducing positional registration errors introduced by separate manufacturing of different functional components and subsequent assembly, and improving the relative positional accuracy and pattern registration consistency between functional areas. Simultaneously, the component is integrally formed from metal material, eliminating reliance on adhesive bonding between light-absorbing and reflective components. This reduces the impact of adhesive layer aging, vibration, shock, and temperature changes on structural stability, improving the component's dimensional stability, mechanical reliability, and adaptability to complex environments.

[0018] (3) It can produce optical functional components with excellent optical properties.

[0019] This invention utilizes the differentiated optical properties of copper and nickel after different surface treatments to construct alternating blackened copper light-absorbing areas and bright nickel reflective areas within the same working surface. A third photolithography step defines the selective electroforming positions of the bright nickel, forming a predetermined grating reflective pattern. After all metal layers have been electroformed, the copper areas not covered by bright nickel are blackened to form high-absorption regions. By leveraging the differences in optical properties between copper and nickel materials and their different surface states, the light-absorbing and reflective functional zoning is achieved, increasing the optical response differences between different regions, improving optical signal contrast, and helping to suppress stray light interference. Attached Figure Description

[0020] Figure 1 This is a top view of an optical component with an alternating Ni / Cu / Ni stack structure prepared according to the process method of this application; Figure 2 This is a formal drawing of an optical component with an alternating Ni / Cu / Ni stack structure, prepared according to the process method of this application; Figures 3-11 A schematic diagram of a fabrication method for an optical component with an alternating Ni / Cu / Ni stack structure according to an embodiment of the present invention.

[0021] In the figure, 101 is the bottom support structure; 102 is the intermediate structural layer; 103 is the light-absorbing layer; 104 is the reflective layer; 201 is the conductive planar substrate; 202 is the photoresist layer I; 203 is the nickel carrier layer; 204 is the photoresist layer II; 205 is the copper functional layer; 206 is the blackened copper layer; 207 is the photoresist layer III; 208 is the bright nickel layer; and 301 is the positive photoresist. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0023] Figures 1 to 11 The optical component and its preparation process of the present invention are described from three aspects: functional layout of the working surface, alternating vertical layer structure, and manufacturing process. Figure 1 The working surface structure of the optical component is shown, wherein the light-absorbing layer 103 and the reflective layer 104 are alternately distributed in the same working surface according to a predetermined grating pattern, forming an optical functional area in which the light-absorbing area and the reflective area alternate. Figure 11 The longitudinally stacked alternating structure of the optical component is shown, which includes a nickel carrier layer 203 formed by electroforming nickel, a copper functional layer 205 located on the nickel carrier layer 203, a blackened copper layer 206 formed by blackening the exposed surface of the copper functional layer 205, and a bright nickel layer 208 selectively electroformed on the surface of the copper functional layer 205. Figures 3 to 11 This section details the complete manufacturing process of the laminated optical components from the perspective of process implementation.

[0024] like Figure 1 As shown, Figure 1 The overall working surface layout of an optical component with an alternating Ni / Cu / Ni stack structure is shown. The component is rectangular in shape, and its shape can be adjusted according to specific optical application requirements. The working surface of this stacked component includes a reflective layer 104 made of bright nickel and a light-absorbing layer 103 formed by blackening the surface of a copper functional layer 205. The reflective layer 104 and the light-absorbing layer 103 are alternately distributed in the planar projection direction according to a predetermined grating pattern, forming an alternating "reflection-absorption" optical functional region. Since the reflective layer 104 is selectively electroformed on the surface of the copper functional layer 205, it and the light-absorbing layer 103 have a height difference along the component thickness direction. During operation, the reflective layer 104 reflects incident light, and the light-absorbing layer 103 absorbs incident light, thereby creating a differentiated optical response.

[0025] like Figure 2As shown, this illustrates the core stacked system of the Ni / Cu / Ni alternating layer optical component, which mainly consists of four parts: a bottom support structure 101, an intermediate structural layer 102, a light-absorbing layer 103, and a reflective layer 104. The bottom support structure 101 is formed by a nickel carrier layer 203, which provides a stable structural support and a relatively flat electroforming growth base for the subsequent intermediate structural layer 102. The reflective layer 104 is composed of a bright nickel layer 208, providing high reflectivity signal output. The light-absorbing layer 103 is composed of a blackened copper layer 206, which has strong light absorption capabilities and helps suppress stray light interference. The nickel carrier layer 203, the copper functional layer 205, and the bright nickel layer 208 are formed through a continuous electroforming process. The exposed surface of the copper functional layer 205 undergoes a subsequent blackening treatment to form a blackened copper layer 206. All structural layers and optical functional areas together constitute an integrated optical component.

[0026] The following will refer to the appendix. Figures 3 to 11 This section details the specific manufacturing process of the Ni / Cu / Ni alternating layer optical component.

[0027] Step S1: As Figure 3 As shown, a positive photoresist 301 with a thickness of 5μm-100μm is uniformly coated on a conductive planar substrate 201 that has undergone standard pretreatment, and then subjected to standard pre-baking and standing treatments as required.

[0028] Step S2: As Figure 4 As shown, a high-precision photolithography process is used to fabricate a photoresist pattern layer I202 on the positive photoresist 301. This step involves ultraviolet exposure of the positive photoresist layer 301 using a mask with a preset pattern. After exposure, the layer is developed, rinsed with deionized water, and dried with nitrogen to obtain the photoresist pattern layer I202.

[0029] Step S3: As Figure 5 As shown, a combination structure of a conductive planar substrate 201 and a molded pattern layer I202 is used as the cathode. Conventional metallic nickel is electroformed in a nickel sulfamate system to form a nickel carrier layer 203 (i.e., the bottom support structure 101 of the stacked alternating structure optical component). The thickness can be guaranteed by adjusting the electroforming time. The function of this nickel carrier layer 203 is to serve as a transition layer to improve the overall adhesion of the stacked film and to smooth out microscopic defects on the substrate surface, providing a smooth interface for the subsequent fabrication of functional layers.

[0030] Step S4: As Figure 6As shown, the nickel carrier layer 203 and the molded pattern layer I202 fabricated in step S3 are subjected to a finishing process. Using the positioning marks formed by photolithography in the previous step as the overlay reference, a molded pattern layer II204 with the same structural features but a greater thickness (100μm~200μm) is formed on the surface of the molded pattern layer I202, ensuring a spatial correspondence between the molded pattern layer II204 and the molded pattern layer I202. The molded pattern layer II204 defines the electroforming area of ​​the subsequent copper functional layer 205, with the bottom of the electroforming area exposing the already formed nickel carrier layer 203. In this embodiment, overlay alignment is calibrated using four corner positioning holes. The thickness of the molded pattern layer II204 is 100μm, and the overlay alignment deviation is controlled within ±0.002mm.

[0031] Step S5: As Figure 7 As shown, a combined structure of a conductive planar substrate 201, a nickel carrier layer 203, and a molded pattern layer II 204 is used as the cathode to perform metallic copper electroforming in an acidic sulfate electroforming system. Copper ions are deposited in the electroforming region defined by the molded pattern layer II 204 to form a copper functional layer 205 located on the surface of the nickel carrier layer 203; the thickness of the copper functional layer 205 is 20 μm to 200 μm.

[0032] Step S6: As Figure 8 As shown, a 30 μm thick positive photoresist 301 is coated on the surface of the copper functional layer 205, and then re-etched using the positioning reference formed by the previous photolithography. After exposure and development, a molded pattern layer III207 with a thickness of 20 μm to 50 μm and specific grating stripes is formed. The molded pattern layer III207 defines the electroforming area according to the predetermined grating pattern, which is used to define the position and geometry of the bright nickel layer 208. In this embodiment, the thickness of the molded pattern layer III207 is 30 μm, and the overlay alignment deviation is controlled within ±0.002 mm.

[0033] Step S7: As Figure 9 As shown, a combination structure of a conductive planar substrate 201, a nickel carrier layer 203, a copper functional layer 205, and a molding pattern layer III 207 is used as the cathode. A bright nickel layer 208 is deposited in the electroforming area defined by the molding pattern layer III 207, so that the bright nickel layer 208 forms a reflective area with a predetermined grating pattern distribution on the surface of the copper functional layer 205. The thickness of the bright nickel layer 208 is 20 μm to 50 μm.

[0034] Step S8: As Figure 10 As shown, after the nickel carrier layer 203, copper functional layer 205 and bright nickel layer 208 are all electroformed, the mold pattern layer I202, mold pattern layer II204 and mold pattern layer III207 are removed to expose the surface of the copper functional layer 205 that is not covered by the bright nickel layer 208.

[0035] like Figure 11 As shown, the copper functional layer 205, which is exposed but not covered by the bright nickel layer 208, is blackened to form a blackened copper layer 206 on its surface, and the blackened copper layer 206 constitutes the light-absorbing layer 103; the bright nickel layer 208 constitutes the reflective layer 104. Thus, the light-absorbing layer 103 and the reflective layer 104 form spatially alternating light-absorbing and reflective areas according to a predetermined grating pattern defined by the molding pattern layer III 207; the predetermined grating pattern is a periodic stripe pattern.

[0036] Step S9: After completing the above blackening treatment, the metal component with the nickel carrier layer 203, copper functional layer 205, blackened copper layer 206, and bright nickel layer 208 formed is peeled off from the conductive planar substrate 201 to obtain the following: Figure 2 The optical component shown has an alternating Ni / Cu / Ni stack structure, wherein the light-absorbing layer 103 has an absorbency of ≥90% and the reflectivity of the reflective layer 104 is ≥70%.

Claims

1. A process for electroforming an optical component with an alternating Ni / Cu / Ni multilayer structure, characterized in that: It includes the following steps implemented in sequence: Step S1: Apply a positive photoresist (301) with a thickness of 5μm-100μm uniformly to the conductive planar substrate (201) after standard pretreatment, and perform standard pre-baking, standing and other treatments as required; Step S2: Use photolithography to create a photoresist pattern layer I (202) on the photoresist (301); Step S3: Using the assembly including the conductive planar substrate (201) and the molded pattern layer I (202) made in step S2 as the cathode, a conventional metallic nickel layer is electroformed to form a nickel carrier layer (203), which serves as the bottom support structure (101) of the stacked alternating structure optical component. Step S4: The nickel carrier layer (203) and the molded pattern layer (202) prepared in step S3 are subjected to a smoothing process. Using the positioning marks formed by photolithography in the previous step as the overlay reference, a molded pattern layer II (204) with the same structural features but a larger thickness is formed on the surface of the molded pattern layer I (202); the thickness of the molded pattern layer II (204) is 100μm~200μm. Step S5: Using the combined structure of conductive planar substrate (201), nickel carrier layer (203) and molded pattern layer II (204) as the cathode, copper ions are deposited in the electroforming area defined by molded pattern layer II (204) to form a copper functional layer (205) on the surface of nickel carrier layer (203), which serves as the intermediate structural layer (102) of the stacked alternating structure optical component. Step S6: Perform a smoothing process on the copper functional layer (205) and the mold pattern layer II (204) made in step S5. Using the positioning marks formed by photolithography in the previous step as the overlay reference, form a mold pattern layer III (207) with a thickness of 20μm~50μm and specific grating stripes on the surface of the mold pattern layer II (204). Step S7: Using the combined structure of the conductive planar substrate (201), nickel carrier layer (203), copper functional layer (205) and molded pattern layer III (207) obtained in step S6 as the cathode, a bright nickel layer (208) is deposited in the electroforming area defined by the molded pattern layer III (207) as the reflective layer (104) of the stacked alternating structure optical component. Step S8: After the nickel carrier layer (203), copper functional layer (205) and bright nickel layer (208) are electroformed, mold pattern layer I (202), mold pattern layer II (204) and mold pattern layer III (207) are removed to expose the surface of the copper functional layer (205) that is not covered by the bright nickel layer (208); then the copper functional layer (205) that is not covered by the bright nickel layer (208) is blackened to form a blackened copper layer (206) on its surface, which serves as the light-absorbing layer (103) of the stacked alternating structure optical component. Step S9: The metal components of the nickel carrier layer (203), copper functional layer (205), blackened copper layer (206) and bright nickel layer (208) formed above are peeled off from the conductive planar substrate (201) to obtain an optical component with an alternating Ni / Cu / Ni stack structure.

2. The process for electroforming Ni / Cu / Ni alternating layer optical components according to claim 1, characterized in that: The light-absorbing layer (103) has an absorbance of ≥90%.

3. The process for electroforming an alternating Ni / Cu / Ni layer optical component according to claim 1, characterized in that: The reflectivity of the reflective layer (104) is ≥70%.

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