Micropore etching process for metal reinforcing plate of folding screen

Abstract

The invention belongs to the technical field of micropore etching processes, and particularly relates to a micropore etching process for a metal reinforcing plate of a folding screen, which comprises the following steps of: sequentially performing plasma treatment and pre-stretching treatment on a metal substrate; selectively forming a transition layer on the surface of the pre-treated base material, coating photoresist, exposing and developing to form a patterned mask with a micropore area and an edge area different in thickness; etching by adopting a circulating process of main etching, water washing, fine-tuning etching and water washing, and controlling the etching temperature and pressure; carrying out ultrasonic cleaning on the etched base material, and carrying out annealing treatment according to requirements; wherein the metal base material is selected from titanium alloy, stainless steel or aluminum alloy, and the thickness of the base material is 50-200 microns.

Description

Technical Field

[0001] This invention belongs to the field of micro-hole etching technology, and particularly relates to a micro-hole etching process for a foldable screen metal reinforcing plate. Background Technology

[0002] As a core innovation direction for terminal products such as smartphones and wearable devices, foldable screens place stringent demands on the comprehensive performance of key structural components. Metal reinforcing plates, as the core supporting component of foldable screens, must simultaneously meet multiple requirements, including flexible bending, structural strength, lightweight design, heat dissipation efficiency, and signal transmission compatibility. The precise fabrication of micro-hole structures is crucial to achieving these performance targets. Micro-hole arrays can not only effectively reduce the weight of the reinforcing plate but also construct heat dissipation channels and optimize high-frequency signal transmission paths, becoming a core technological breakthrough for improving the overall experience of foldable screens. However, existing micro-hole etching processes are difficult to adapt to the differentiated needs of different functional areas of foldable screens (such as core stress areas, signal via areas, and chip heat dissipation areas), generally suffering from insufficient aspect ratio, low micro-hole precision, numerous burr residues, and short folding lifespan. They cannot achieve a balance between high folding reliability and ultra-fine micro-holes, or between high aspect ratio and structural stability.

[0003] The etching process in the industry currently faces several technical bottlenecks: On the one hand, the poor compatibility between the substrate and etching parameters, and the lack of targeted design for different metal substrates such as titanium alloy, stainless steel, and aluminum alloy, lead to defects such as edge collapse and insufficient edge perpendicularity in some scenarios, affecting assembly accuracy and usage stability. On the other hand, unreasonable mask layer design and lack of optimization in the cyclic etching process result in poor micropore diameter consistency, high signal transmission loss, and imperfect post-processing, making the product prone to cracking under extreme temperature and humidity environments and causing rapid degradation of folding fatigue performance. At the same time, the high cost of high-end processes and the lack of simplified and reliable process solutions for mid-range foldable screen products make it difficult to meet the mass production needs of different levels of terminal products, thus restricting the large-scale popularization and performance upgrade of foldable screen technology. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned technical problems by providing a micro-hole etching process for foldable screen metal reinforcing plates.

[0005] In view of this, the present invention provides a micro-hole etching process for a foldable screen metal reinforcing plate, comprising the following steps: Step 1: Perform plasma treatment and pre-stretching treatment on the metal substrate in sequence; Step 2: Selectively form a transition layer on the surface of the pretreated substrate, then coat it with photoresist and expose and develop it to form a patterned mask with different thicknesses in the micro-hole area and the edge area; Step 3: Etching is performed using a cyclic process of main etching, water washing, fine-tuning etching, and water washing, while controlling the etching temperature and pressure; Step 4: Perform ultrasonic cleaning on the etched substrate and annealing treatment as required; The metal substrate is selected from titanium alloy, stainless steel or aluminum alloy, and the substrate thickness is 50μm-200μm.

[0006] Preferably, in step one, the power of the plasma treatment is 100W-150W, and the treatment time is 3min-5min; the pressure of the pre-stretching treatment is 50MPa-150MPa, and the treatment time is 10min-20min.

[0007] Preferably, in step two, the transition layer is selected from a Cr transition layer or a Ni transition layer, wherein the thickness of the Cr transition layer is 70nm-100nm and the thickness of the Ni transition layer is 50nm-90nm; or the transition layer can be omitted and photoresist can be directly coated.

[0008] Preferably, in step two, the thickness of the photoresist in the micropore region is 0.8μm-1.2μm, and the thickness of the edge region is 1.5μm-2.0μm; when preparing a multifunctional reinforcing plate with grooves, the thickness of the photoresist in the groove region is 2.0μm.

[0009] Preferably, in step three, the number of cyclic etching cycles is 5 to 10 times, and the parameters for a single cycle are: main etching time 30s-60s, water washing time 10s-15s, fine-tuning etching time 10s-30s, water washing time 10s-15s; etching temperature 30℃-60℃, and etching pressure 0.1MPa-0.3MPa.

[0010] Preferably, in step four, the ultrasonic cleaning time is 8-10 minutes; the annealing temperature is 180℃-200℃, the processing time is 45-60 minutes, and the protective gas is nitrogen or argon.

[0011] Preferably, the metal substrate is a Ti-6Al-4V titanium alloy or a Ti-3Al-2.5V titanium alloy, the plasma treatment power is 120W-140W, and the pre-stretching pressure is 80MPa-150MPa.

[0012] Preferably, the metal substrate is stainless steel, selected from 304 stainless steel, 301 stainless steel or 316L stainless steel, the plasma treatment power is 130W-150W, and the pre-stretching pressure is 70MPa-110MPa.

[0013] Preferably, the metal substrate is an aluminum alloy, selected from 6061-T6 aluminum alloy, 6063 aluminum alloy or 5052 aluminum alloy, the plasma treatment power is 100W-120W, and the pre-stretching pressure is 50MPa-90MPa.

[0014] Preferably, when preparing a high heat dissipation type or a large-size micro-hole array type reinforcing plate, the etching temperature is 60℃, the etching pressure is 0.3MPa, the number of cyclic etchings is 6 to 7, the main etching time is 60s, and the fine-tuning etching time is 20s.

[0015] The beneficial effects of this invention are: By precisely matching the metal substrate with the core process parameters, and optimizing the pretreatment, mask preparation, and etching processes for different types of substrates, the structural defects commonly found in traditional etching processes are effectively solved, resulting in a comprehensive improvement in the key performance of the foldable screen's metal reinforcement plate. Whether it's the bending reliability required in the core stress area, the structural integrity required in the signal transmission area, or the channel rationality required in the heat dissipation area, precise adaptation can be achieved through targeted adjustments to the process parameters, fully covering the differentiated usage needs of different functional areas of the foldable screen.

[0016] This process combines multi-functional integration capabilities with all-scenario adaptability, ensuring performance while balancing practicality and economy. Through innovative etching process design, it enables the integrated fabrication of various structural features, adapting to the assembly requirements of special components. Optimized post-processing allows the product to withstand extreme environments, significantly improving stability. Simultaneously, the simplified process reduces production costs while maintaining basic performance, achieving an optimized balance between lightweight design and structural strength. This provides core support for enhancing the user experience of foldable screens in multiple application scenarios, facilitating the wider market adoption of foldable screen technology. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of a micro-hole etching process for a foldable screen metal reinforcing plate according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0019] Example 1: High folding life type; Application scenario: Reinforcing plate for inner screen of flagship foldable screen (core stress area); Substrate: Ti-6Al-4V titanium alloy, 100μm thick; Key parameters: Pretreatment: Plasma 120W / 4min; Pre-stretching 120MPa / 20min; Mask: 80nm Cr transition layer; photoresist (1.0μm in micro-hole area, 1.8μm in edge area); Etching: 8 cycles (main etching 45s, water rinse 12s, fine-tuning 15s, water rinse 12s); temperature 45℃, pressure 0.2MPa; Post-treatment: sonication for 8 min; annealing at 180℃ for 45 min (nitrogen gas); Results: Micropore diameter 30μm, aspect ratio 4:1, accuracy ±0.8μm, burrs <0.2μm, folding life 150,000 times (180° bend). Example 2: Ultrafine microporous type; Application scenario: Signal through-hole reinforcement plate for foldable screens (high-frequency signal transmission); Substrate: 316L stainless steel, 50μm thick; Key parameters: Pretreatment: Plasma 150W / 3min; Pre-stretching 80MPa / 15min; Mask: 50nm Ni transition layer; photoresist (0.8μm in micro-hole area, 1.5μm in edge area); Etching: 10 cycles (main etching 30s, water rinse 10s, fine-tuning 10s, water rinse 10s); temperature 35℃, pressure 0.15MPa; Results: Micropore diameter 10μm, aspect ratio 2:1, accuracy ±0.5μm, no edge collapse, signal transmission loss reduced by 15%; Example 3: High heat dissipation type (large aperture and high aspect ratio); Application scenario: Reinforcement board for the chip area of ​​foldable screen (heat dissipation requirement); Substrate: 6061-T6 aluminum alloy, 150μm thick; Key parameters: Pretreatment: Plasma 100W / 5min; Pre-stretching 50MPa / 10min Mask: Cr transition layer 100nm; photoresist (micro-hole area 1.2μm, edge area 2.0μm) Etching: 6 cycles (main etching 60s, water rinse 15s, fine-tuning 20s, water rinse 15s); temperature 60℃, pressure 0.3MPa; Results: Micropore diameter 80μm, aspect ratio 5:1, porosity 30%, heat dissipation efficiency improved by 40%, weight reduction by 25%; Example 4: Lightweight version; Application scenario: Lightweight reinforcement plate for the outer screen of foldable screens; Substrate: 5052 aluminum alloy, 80μm thick; Key parameters: Pretreatment: Plasma 110W / 4min; Pre-stretching 60MPa / 12min Mask: 60nm Ni transition layer; Photoresist (0.9μm in micro-hole area, 1.6μm in edge area) Etching: 7 cycles (main etching 40s, water rinse 12s, fine-tuning 12s, water rinse 12s); temperature 40℃, pressure 0.2MPa; Results: 50μm micropore diameter, 100 pores / mm² array density, 3:1 aspect ratio, 35% weight reduction, and 80% flexural strength retention; Example 5: High-precision type; Application scenario: Reinforcing plate for foldable screen camera module (assembly tolerance requirements); Substrate: 304 stainless steel, 60μm thick; Key parameters: Pretreatment: Plasma 140W / 3min; Pre-stretching 100MPa / 18min Mask: Cr transition layer 70nm; photoresist (micro-hole area 1.0μm, edge area 1.7μm) Etching: 9 cycles (main etching 35s, water rinse 11s, fine-tuning 13s, water rinse 11s); temperature 32℃, pressure 0.12MPa; Results: Micropore diameter 20μm, aspect ratio 2.5:1, accuracy ±0.5μm, edge perpendicularity 98%, assembly yield 99.2%; Example 6: Wide temperature adaptable type (for use at -40℃ to 85℃); Application scenario: Outdoor-specific folding screen reinforcement plate (extreme environment); Substrate: Ti-3Al-2.5V titanium alloy, 120μm thick; Key parameters: Pretreatment: Plasma 130W / 5min; Pre-stretching 150MPa / 20min; Mask: 90nm Ni transition layer; photoresist (1.1μm in micropore area, 1.9μm in edge area); Etching: 8 cycles (main etching 50s, water rinse 14s, fine-tuning 18s, water rinse 14s); temperature 50℃, pressure 0.25MPa; Post-treatment: sonication for 10 min; annealing at 200℃ for 60 min (argon gas); Results: The micropores have a diameter of 40 μm and an aspect ratio of 3.5:1. They showed no cracking after being subjected to high and low temperature cycles (1 hour each at -40℃ and 85℃, 100 cycles), and the accuracy remained at ±1.0 μm. Example 7: Low-cost type (simplified process adapted to mid-range machines); Application scenario: General reinforcement plate for mid-range foldable screens; Substrate: 301 stainless steel, 90μm thick; Key parameters: Pretreatment: Plasma 100W / 3min; Pre-stretching 70MPa / 10min; Mask: Metal transition layer omitted; Photoresist (1.2μm in micro-hole area, 1.5μm in edge area); Etching: 5 cycles (main etching 55s, water rinse 15s, fine-tuning 16s, water rinse 15s); temperature 55℃, pressure 0.28MPa; Results: Micropore diameter 60μm, aspect ratio 2:1, accuracy ±1.2μm, cost reduction of 20%, folding life of 80,000 cycles; Example 8: Large-size micropore array type (100μm pore diameter); Application scenario: Reinforcement plate for battery area of ​​foldable screen (heat dissipation + weight reduction); Substrate: 6063 aluminum alloy, 200μm thick; Key parameters: Pretreatment: Plasma 120W / 4min; Pre-stretching 90MPa / 16min; Mask: 80nm Cr transition layer; photoresist (1.2μm in micro-hole area, 2.0μm in edge area); Etching: 7 cycles (main etching 60s, water rinse 15s, fine-tuning 20s, water rinse 15s); temperature 60℃, pressure 0.3MPa; Results: Micropore diameter 100μm, aspect ratio 4:1, array area 50mm×50mm, porosity 40%, heat dissipation rate increased by 50%; Example 9: Ultra-thin substrate type (50μm thickness); Application scenario: Ultra-thin reinforcing plate for the hinge area of ​​foldable screens; Substrate: Ti-6Al-4V titanium alloy, 50μm thick; Key parameters: Pretreatment: Plasma 140W / 3min; Pre-stretching 80MPa / 12min; Mask: 60nm Ni transition layer; photoresist (0.8μm in micro-hole area, 1.5μm in edge area); Etching: 6 cycles (main etching 30s, water rinse 10s, fine-tuning 12s, water rinse 10s); temperature 30℃, pressure 0.1MPa; Results: Micropore diameter 25μm, depth-to-width ratio 3:1, thickness only 50μm, bending radius ≤3mm, no breakage; Example 10: Multifunctional integrated type; Application scenario: Reinforcement plate for touch area of ​​foldable screen (for sensor assembly); Substrate: 316L stainless steel, 80μm thick; Key parameters: Pretreatment: Plasma 130W / 4min; Pre-stretching 110MPa / 15min Mask: Cr transition layer 70nm; photoresist (micro-hole area 1.0μm, groove area 2.0μm, edge area 1.8μm); Etching: First, groove etching (main etching 80s, fine-tuning 30s), then micro-hole etching (7 cycles); temperature 40℃, pressure 0.2MPa; Results: Micropore diameter 30μm (depth-to-width ratio 3:1), groove depth 20μm, accuracy ±0.8μm, seamless assembly with compatible sensors.

[0020] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A micro-hole etching process for a foldable screen metal reinforcing plate, characterized in that: Includes the following steps: Step 1: Perform plasma treatment and pre-stretching treatment on the metal substrate in sequence; Step 2: Selectively form a transition layer on the surface of the pretreated substrate, then coat it with photoresist and expose and develop it to form a patterned mask with different thicknesses in the micro-hole area and the edge area; Step 3: Etching is performed using a cyclic process of main etching, water washing, fine-tuning etching, and water washing, while controlling the etching temperature and pressure; Step 4: Perform ultrasonic cleaning on the etched substrate and annealing treatment as required; The metal substrate is selected from titanium alloy, stainless steel or aluminum alloy, and the substrate thickness is 50μm-200μm.

2. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 1, characterized in that: In step one, the power of the plasma treatment is 100W-150W, and the treatment time is 3min-5min; the pressure of the pre-stretching treatment is 50MPa-150MPa, and the treatment time is 10min-20min.

3. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 1, characterized in that: In step two, the transition layer is selected from Cr transition layer or Ni transition layer, wherein the thickness of Cr transition layer is 70nm-100nm and the thickness of Ni transition layer is 50nm-90nm; or the transition layer is omitted and photoresist is directly coated.

4. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 1, characterized in that: In step two, the thickness of the photoresist in the micropore region is 0.8μm-1.2μm, and the thickness of the edge region is 1.5μm-2.0μm; when preparing a multifunctional reinforcing plate with grooves, the thickness of the photoresist in the groove region is 2.0μm.

5. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 1, characterized in that: In step three, the number of cyclic etching cycles is 5 to 10 times, and the parameters for a single cycle are as follows: main etching time 30s-60s, water washing time 10s-15s, fine-tuning etching time 10s-30s, water washing time 10s-15s; etching temperature 30℃-60℃, and etching pressure 0.1MPa-0.3MPa.

6. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 1, characterized in that: In step four, the ultrasonic cleaning time is 8-10 minutes; the annealing temperature is 180℃-200℃, the processing time is 45-60 minutes, and the protective gas is nitrogen or argon.

7. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 2, characterized in that: The metal substrate is a Ti-6Al-4V titanium alloy or a Ti-3Al-2.5V titanium alloy, the plasma treatment power is 120W-140W, and the pre-stretching pressure is 80MPa-150MPa.

8. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 2, characterized in that: The metal substrate is stainless steel, selected from 304 stainless steel, 301 stainless steel or 316L stainless steel, the plasma treatment power is 130W-150W, and the pre-stretching pressure is 70MPa-110MPa.

9. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 2, characterized in that: The metal substrate is an aluminum alloy, selected from 6061-T6 aluminum alloy, 6063 aluminum alloy or 5052 aluminum alloy, the plasma treatment power is 100W-120W, and the pre-stretching pressure is 50MPa-90MPa.

10. The micro-hole etching process for a foldable screen metal reinforcing plate according to claim 5, characterized in that: When fabricating high heat dissipation or large-size micro-hole array reinforcement plates, the etching temperature is 60℃, the etching pressure is 0.3MPa, the number of cyclic etchings is 6 to 7, the main etching time is 60s, and the fine-tuning etching time is 20s.

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