Manufacturing method of fine circuit
Through multiple wet etching processes, combined with high-precision exposure and development processes, the problem of difficult to take into account both the line depth and width accuracy in the prior art is solved, and fine line production with high-deep and aspect ratio is achieved, and line quality and product yield are improved.
Patent Information
- Application Number
- CN202510414660.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2025-06-17
AI Technical Summary
The prior art is difficult to take into account the depth and width accuracy of fine lines, resulting in uneven line widths, affecting electrical performance and stability.
Multiple wet etching processes are adopted, the first etching is in the vertical direction and the second etching is in the horizontal direction. By adjusting the concentration, temperature and time of the etching liquid, combined with high-precision exposure and development processes, the line size is accurately controlled.
The fine line production with high-deep aspect ratio is achieved, ensuring accurate control of line size, avoiding short circuits, and improving line quality and product yield.
Smart Images
Figure CN120166639A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of manufacturing fine-line electronic devices, and specifically to a method for manufacturing fine lines. Background Art
[0002] In the era of the rapid development of current electronic technology, electronic devices are constantly moving towards miniaturization and high performance. This has led to increasingly high requirements for the manufacturing of fine lines, especially for those electronic circuits that require a higher aspect ratio. In the manufacturing of high-end electronic devices such as smart phones, high-performance servers, and advanced artificial intelligence chips, in order to integrate more functional modules in a limited space and achieve faster data transmission and processing speeds, fine lines must have a larger aspect ratio while ensuring high precision. In the prior art, for a relatively thick conductive metal layer, the existing single-etching process is difficult to balance the depth and width accuracy of the lines. If sufficient etching depth is to be achieved, it often leads to excessive etching of the line width, resulting in uneven line width, seriously affecting the electrical performance and stability of the lines; and if the etching amount is reduced to control the line width, the required etching depth cannot be satisfied, and specific circuit functions cannot be achieved. Summary of the Invention
[0003] The purpose of the present invention is to provide a method for manufacturing fine lines to solve the problems raised in the above background art.
[0004] To achieve the above purpose, the present invention provides the following technical solution: A method for manufacturing fine lines, comprising the following steps:
[0005] Step 1: Prepare a board with a metal layer and a substrate, the metal layer covering the surface of the substrate, the metal layer including but not limited to metals with conductive effects such as copper and aluminum, and the substrate not being limited to PET;
[0006] Step 2: Set a photoresist or dry film on the surface of the metal layer, and form a circuit pattern through exposure and development processes;
[0007] Step 3: Perform the first wet etching, mainly etching in the vertical direction, etching from the developed circuit pattern until the width of the photoresist covering the circuit surface is basically the same as the circuit width, the circuit being relatively thick and some circuits being in a partially short-circuited state due to the unetched metal connection between them;
[0008] Step 4: Perform the second wet etching, mainly etching in the horizontal direction, narrowing the circuit width, and etching away the metal in the partially short-circuited area caused by the first etching;
[0009] Step 5: Determine whether to perform subsequent etching based on whether the line width meets the product shipping specifications. If not, repeat the operations of the first wet etching and the second wet etching until the required line width is achieved.
[0010] Preferably, during the first wet etching process, the etching solution is selected from acidic copper chloride etching solution, alkaline etching solution, and copper sulfate etching solution. The concentration of the etching solution is selected within the range of 1-50% according to the metal type, thickness, and characteristics of the etching equipment. The etching temperature is controlled at 40-60°C, and the etching time is determined within 5-30 minutes based on the metal etching amount and etching rate.
[0011] Preferably, during the second wet etching process, the etching solution is a solution that is compatible with the first etching solution and can achieve effective etching in the horizontal direction. The concentration of the etching solution is adjusted within the range of 1-50% according to the line state and etching effect after the first etching. The etching temperature is controlled at 35-55°C, and the etching time is set within 3-15 minutes according to the requirement of line width change.
[0012] Preferably, if wet etching is performed for the third or more times, the etching solution is a solution that is compatible with the previous etching solutions and can achieve effective etching in the horizontal direction. The concentration of the etching solution is 0.1-10%, the etching temperature is controlled at 30-50°C, and the etching time is 1-10 minutes. The specific parameters are adjusted according to the previous etching results and the final requirements of the product.
[0013] Preferably, after each etching is completed, the board is rinsed multiple times with deionized water until no surface residual etching solution is detected, and then the board is dried by low-temperature drying or clean air drying to avoid damaging the circuit.
[0014] Preferably, the photoresist or dry film is set on the surface of the metal layer by coating, laminating, etc. When coating, the coating thickness deviation is controlled within ±0.5μm to ensure thickness uniformity. When laminating, vacuum laminating or other processes that can effectively remove bubbles and impurities are used;
[0015] During the exposure and development processes, the exposure intensity is 100-500mJ / cm 2 , the exposure time is 10-60 seconds, the concentration of the developer is 1-10%, and the development time is 10-60 seconds. The specific parameters are accurately adjusted according to the line pattern accuracy requirements and the characteristics of the photoresist or dry film.
[0016] Preferably, the initial thickness of the metal layer is 10-100μm, the fine line width finally formed after multiple etchings is 5-20μm, and the line pitch is 5-20μm. The specific dimensions are accurately determined according to the requirements of electrical performance, signal transmission, etc. in the product design.
[0017] Preferably, during the exposure process, a high-precision exposure device with a resolution of 2 μm is used, and during the exposure process, the energy calibration system provided by the device is used to accurately control the distribution of exposure energy to ensure that the exposure uniformity deviation of each part of the circuit pattern is within ±5%.
[0018] Preferably, during each etching process, the concentration, temperature, etching rate and other parameters of the etching solution are monitored in real time by online sensors, and these parameters are dynamically adjusted according to a preset control model using an automated control system to ensure the stability and consistency of the etching process and control the etching rate fluctuation within ±5%.
[0019] Preferably, after the fine circuit is manufactured, the circuit is comprehensively inspected, including the width, spacing, conductivity, and insulation of the circuit. The resolution of the inspection equipment is 1 μm to ensure that the circuit quality meets the product requirements.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] In terms of technology and product quality, this fine circuit production method can process thick metal layers through multiple etching methods, realize the production of fine circuits with high aspect ratios, and accurately control the circuit size. Through precise control of etching parameters and exposure and development parameters, it ensures uniform etching, avoids short circuits, improves circuit quality and product yield, and uses high-precision exposure equipment and energy control, strict testing standards and high-resolution equipment to ensure that product quality meets standards. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a fine circuit forming diagram of the present invention.
[0023] In the figure: 1. dry film; 2. metal layer; 3. substrate. DETAILED DESCRIPTION
[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0025] See also Figure 1 The present invention provides a technical solution: a method for making fine circuits, step 1: preparing a plate, selecting a plate with a PET substrate and a copper metal layer on the surface. The initial thickness of the copper metal layer is set to 50 μm, which meets common production requirements and is within the etchable range.
[0026] Step 2: Set the photoresist and use coating to set the photoresist on the surface of the copper metal layer. During the coating process, strictly control the coating thickness deviation within ±0.5μm to ensure the uniformity of the photoresist thickness. After the photoresist coating is completed, enter the exposure and development stage. During exposure, use high-precision exposure equipment with a resolution of 2μm, and use the energy calibration system of the equipment to accurately control the distribution of exposure energy to ensure that the exposure uniformity deviation of each part of the circuit pattern is within ±5%. The exposure intensity is set to 300mJ / cm 2 , the exposure time is 30 seconds. The developer concentration is configured to be 5%, and the development time is controlled at 30 seconds. Through such parameter settings, an accurate circuit pattern is formed according to the circuit pattern accuracy requirements and photoresist characteristics.
[0027] Step 3: For the first wet etching, the etching solution is acidic copper chloride etching solution, and its concentration is determined to be 20% according to the characteristics, thickness and etching equipment characteristics of copper metal. The etching temperature is controlled at 50°C, and the etching time is set to 15 minutes according to the amount of metal etching and the etching rate. During the etching process, etching is mainly carried out in the vertical direction until the developed circuit pattern is etched to the point where the width of the photoresist covering the circuit surface is basically the same as the circuit width. At this time, the circuit is thicker, and some circuits are in a partial short-circuit state due to unetched metal connections. The concentration, temperature and etching rate of the etching solution are monitored in real time by online sensors, and these parameters are dynamically adjusted according to the preset control model using an automated control system to ensure the stability and consistency of the etching process and control the etching rate fluctuation within ±5%.
[0028] Step 4: For the second wet etching, the etching solution is compatible with the first etching solution and can achieve effective etching in the horizontal direction. According to the circuit status and etching effect after the first etching, the etching solution concentration is adjusted to 15%. The etching temperature is controlled at 45°C, and the etching time is set to 8 minutes according to the change in circuit width. This etching is mainly carried out in the horizontal direction, with the purpose of narrowing the circuit width and etching away the metal in the short-circuit area caused by the first etching. Similarly, during the etching process, real-time monitoring is performed through online sensors and parameters are dynamically adjusted using an automated control system to ensure a stable etching process.
[0029] After etching, the board is rinsed with deionized water several times until no residual etching liquid is detected on the surface. After that, the board is dried by low-temperature drying to avoid damage to the circuit. The circuit width is measured and found to be 12μm at this time, while the product shipping specification requires a fine circuit width of 10μm.
[0030] Step 5: Since the line width does not meet the product shipping specifications, the operations of the first wet etching and the second wet etching are repeated. For the third etching, which is the second time of repeating the first etching operation, the etching solution is still the acidic copper chloride etching solution, with the concentration adjusted to 15%, the etching temperature controlled at 45°C, and the etching time set to 10 minutes. For the fourth etching, which is the second time of repeating the second etching operation, the etching solution is selected as a solution that is compatible with the previous one and can achieve effective etching in the horizontal direction, with the concentration adjusted to 10%, the etching temperature controlled at 40°C, and the etching time set to 5 minutes. After the etching is completed, the board is rinsed and dried again.
[0031] Measure the line width again. At this time, the line width is 10 μm, which meets the dimensions determined by the requirements of electrical performance, signal transmission, etc. in the product design. Subsequently, a comprehensive inspection of the circuit is carried out. The inspection contents include the width, spacing, conductivity, and insulation of the circuit. The resolution of the inspection equipment is 1 μm. After inspection, the circuit quality meets the product requirements, and thus the production of the fine circuit is completed. The finally formed fine circuit has a width of 10 μm and a line spacing of 10 μm.
[0032] In Figure 1 , Figure A shows the circuit pattern formed after development; Figure B shows the front view of the circuit after the first etching; Figure C shows the side view of the circuit after the first etching; Figure D shows the side view of the circuit after the second etching; Figure E shows the side view of the circuit after multiple etchings. Figures B and C represent the same figure, and the difference is that Figure B is the front view and Figure C is the equivalent side view of Figure B.
[0033] The yellow light process is divided into dry etching and wet etching. The present invention adopts the wet process mode to complete the formation of the fine circuit. When the metal layer of the circuit is relatively thick, multiple wet etchings are continuously carried out to form a precision circuit, as shown in Figure 1。Since wet etching is isotropic, that is, etching has no directionality and selectivity, multiple wet etching processes are adopted to construct precise circuits. First, the rough etching of the circuit is completed, that is, the vertical etching is completed in the first step of etching, that is, the process from Figure A to Figure B. The horizontal etching is relatively small, and the width of the photoresist covering the circuit surface is basically the same as the circuit width; the circuit is relatively thick, the spacing is short, and some circuits are connected by unetched metal, that is, in a partial short-circuit state. After the circuit is formed, the second wet etching is carried out, and the horizontal etching is carried out, that is, the process from Figure C to Figure D. Since there is photoresist on the circuit surface, the second etching not only makes the circuit width narrower, but also etches the metal in the partial short-circuit area clean in the previous etching step, so that the circuits of the electronic device will not have functional defects such as short circuits. If the width of the circuit in the second etching is not within the shipping specifications of the product, the third wet etching can be continued, that is, the process from Figure D to Figure E, to make the circuit narrower. Since the circuit surface is protected by photoresist, the etching speed in subsequent etching is much slower than that in the first etching, ensuring the realization of more delicate circuits.
[0034] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for making a fine circuit, characterized in that: The following steps are involved: Step 1: Prepare a plate having a metal layer and a substrate, wherein the metal layer covers the surface of the substrate, the metal layer includes but is not limited to metals with conductive effects such as copper and aluminum, and the substrate is not limited to PET; Step 2: Disposing a photoresist or dry film on the surface of the metal layer, and forming a circuit pattern through exposure and development processes; Step 3: Perform the first wet etching, mainly in the vertical direction, from the developed circuit pattern to the photoresist width covered on the circuit surface is basically the same as the circuit width, the circuit is thicker and some circuits are in a partial short circuit state due to the unetched metal connection; Step 4: Perform a second wet etching, mainly in the horizontal direction, to narrow the line width and etch away the metal in the partial short-circuit area caused by the first etching; Step 5: Determine whether to perform subsequent etching based on whether the line width meets the product shipping specifications. If not, repeat the first wet etching and the second wet etching operations until the required line width is reached.
2. The method for manufacturing a fine circuit according to claim 1, characterized in that: During the first wet etching process, the etching solution is selected from acidic cupric chloride etching solution, alkaline etching solution, and copper sulfate etching solution. The etching solution concentration is selected in the range of 1-50% according to the metal type, thickness and etching equipment characteristics. The etching temperature is controlled at 40-60° C., and the etching time is determined within 5-30 minutes according to the metal etching amount and etching rate.
3. The method for manufacturing a fine circuit according to claim 2, characterized in that: During the second wet etching process, the etching solution is a solution that is compatible with the first etching solution and can achieve effective etching in the horizontal direction. The etching solution concentration is adjusted within the range of 1-50% according to the circuit state and etching effect after the first etching. The etching temperature is controlled at 35-55°C, and the etching time is set within 3-15 minutes according to the circuit width change requirements.
4. The method for manufacturing a fine circuit according to claim 3, characterized in that: If the wet etching is performed for the third time or more, the etching solution is compatible with the previous etching solution and can achieve effective etching in the horizontal direction. The etching solution concentration is 0.1-10%, the etching temperature is controlled at 30-50°C, and the etching time is 1-10 minutes. The specific parameters are adjusted according to the previous etching results and the final requirements of the product.
5. The method for manufacturing a fine circuit according to claim 4, characterized in that: After each etching is completed, the board is rinsed multiple times with deionized water until no residual etching liquid is detected on the surface. The board is then dried by low-temperature drying or clean air drying to avoid damage to the circuit.
6. The method for manufacturing a fine circuit according to claim 1, characterized in that: The photoresist or dry film is disposed on the surface of the metal layer by coating, laminating, etc. During coating, the coating thickness deviation is controlled within ±0.5 μm to ensure thickness uniformity. During laminating, vacuum laminating or other processes that can effectively eliminate bubbles and impurities are adopted; During the exposure and development process, the exposure intensity is 100-500mJ / cm 2 The exposure time is 10-60 seconds, the developer concentration is 1-10%, and the development time is 10-60 seconds. The specific parameters are precisely adjusted according to the circuit pattern accuracy requirements, photoresist or dry film characteristics.
7. A method for manufacturing a fine circuit according to claim 6, characterized in that: The initial thickness of the metal layer is 10-100 μm. After multiple etchings, the final fine line width is 5-20 μm, and the line spacing is 5-20 μm. The specific size is accurately determined based on the electrical performance, signal transmission and other requirements in the product design.
8. The method for manufacturing a fine circuit according to claim 7, characterized in that: During the exposure process, high-precision exposure equipment with a resolution of 2μm is used. During the exposure process, the equipment's built-in energy calibration system is used to accurately control the distribution of exposure energy to ensure that the exposure uniformity deviation of each part of the circuit pattern is within ±5%.
9. The method for manufacturing a fine circuit according to claim 8, characterized in that: During each etching process, online sensors are used to monitor parameters such as the concentration, temperature and etching rate of the etching solution in real time. The automated control system is used to dynamically adjust these parameters according to the preset control model to ensure the stability and consistency of the etching process and control the etching rate fluctuation within ±5%.
10. The method for manufacturing a fine circuit according to claim 9, characterized in that: After the fine circuit is produced, the circuit is comprehensively tested. The test content includes the width, spacing, conductivity, and insulation of the circuit. The resolution of the detection equipment is 1μm to ensure that the circuit quality meets the product requirements.