Etching processing is a precision manufacturing process that uses chemical reactions to remove metal materials. It has the characteristics of not generating mechanical stress, being suitable for processing complex patterns, and being able to process micro-holes and thin sheets. It is applied in fields such as electronics, automobiles, communications, medical, instruments, and precision machinery.
However, etching is not simply immersing metal into an etching solution for corrosion. In the actual processing, several factors—including the material, pre-treatment, photoresist, exposure and development, etching solution parameters, etching time, and post-treatment—can affect the final product’s dimensions and surface quality. Therefore, during etching processing, attention should be focused on the following aspects.
1. First, confirm the metal material
The chemical properties of different metals vary, and their reactions to etching solutions are different. Therefore, before processing, it is necessary to clarify the material grade, thickness, and material condition. Common etching materials include stainless steel, copper, titanium, molybdenum, nickel, and some alloy materials. Different materials require matching different etching systems and processing parameters. For example, thin sheet materials are more susceptible to undercutting during etching, while thicker materials need to consider dimensional changes caused by longer etching times. Therefore, before determining the processing plan, the material type and thickness should be confirmed, rather than simply processing all metals using the same parameters.
2. Proper pre-treatment of the material surface
Pre-treatment is a step in the etching process that is often overlooked. If the metal surface has oil, oxide layers, dust, or other contaminants, it will affect the adhesion between the photoresist and the metal surface. During subsequent etching, issues such as film lifting, penetration, or pattern defects may occur. Therefore, before applying or coating photoresist, cleaning, degreasing, and necessary surface treatment should be carried out according to the material situation to keep the metal surface relatively clean. Only with a stable pre-treatment can the subsequent exposure, development, and etching processes be more easily controlled.
3. Uniform adhesion of the photoresist
Etching processing usually requires using photoresist to protect areas that should not be etched, so the quality and adhesion of the photoresist directly affect the product pattern. During the lamination process, attention should be paid to pressure, temperature, speed, and surface cleanliness. If there are air bubbles, impurities, or poorly adhered areas between the photoresist and the metal, the etching solution may penetrate the protected area, ultimately causing burrs, notches, or dimensional deviations. For precision-etched parts, especially micro-holes, fine lines, and narrow gaps, the uniformity of the photoresist is even more critical.
4. Exposure and Development Need to Be Controlled and Stable
The purpose of exposure is to transfer the design pattern onto the photosensitive material. Exposure time, light intensity, and the precision of the film or other graphic carriers all affect the pattern transfer outcome.
Insufficient exposure may result in unclear pattern edges, while overexposure may cause changes in the pattern size.
The development step also needs to be controlled. If development is insufficient, the areas that should be removed may not be fully opened, affecting subsequent etching; if development is excessive, it may affect the protected areas.
Therefore, for precision products, it is necessary to match exposure and development parameters according to material thickness, the photosensitive material, and the characteristics of the pattern.
5. Etching Solution Parameters Need to Be Maintained Stable
The etching solution is one of the core factors in the entire processing operation. Its concentration, temperature, circulation status, and active components all affect etching speed and processing results.
If the condition of the etching solution changes significantly, it may cause dimensional inconsistencies within the same batch of products.
During batch processing, it is necessary to continuously monitor the etching solution and adjust relevant parameters according to actual conditions to avoid significant fluctuations in etching capability.
Meanwhile, the spray pressure, spray direction, and flow rate of the etching solution also affect the uniformity of the product surface etching.
6. Pay Attention to Controlling Undercutting Issues
Although etching processing can achieve complex patterns, etching is not performed strictly vertically downward.
In practical processing, besides corroding in the direction of the material thickness, the etching solution also corrodes the material beneath the protective film to some extent. This phenomenon is usually called undercutting.
The thicker the material and the longer the etching time, the more attention is generally needed regarding the impact of undercutting on dimensions.
Therefore, when designing etched patterns, compensation design needs to be made considering material thickness, etching characteristics, and target dimensions, rather than directly creating patterns according to the final product size.
7. Micropores and Fine Line Structures Need Key Control
For micropores, narrow slits, fine lines, and other delicate structures, dimensional changes during the etching process can be more significant.
For example, if the diameter of micropores is small, improper control of etching time may cause the pore size to enlarge; fine line structures may become narrower due to lateral etching.
Therefore, when processing precision micropores, narrow slits, precision gaskets, code disks, and similar products, it is important to control pattern design, material thickness, photoresist, etching rate, and etching time.
When necessary, sample tests can be used to verify the actual etching dimensions, then adjust the engineering patterns based on the inspection results.
8. Attention Should Be Paid to Etching Time
Etching time is neither better the longer nor better the shorter.
If the time is insufficient, the material may not be fully etched, leading to residues, blocked holes, or areas not fully opened on the product.
If the time is too long, lateral etching may increase, causing changes in pore diameter, line width, and overall dimensions.
Therefore, etching time needs to be determined comprehensively based on the material, thickness, etchant condition, and product structure. During mass production, attention should also be paid to variations in etching rate between different batches.
9. Timely Cleaning After Etching
After etching, residues such as etching solution, reaction products, and photoresist may remain on the product surface.
If cleaning is insufficient, these residues may affect the product appearance and subsequent processes, and can even cause further corrosion on the metal surface.
Therefore, after etching, cleaning, resist removal, re-cleaning, and drying treatments are usually required.
For electronic, optical, and precision parts with higher cleanliness requirements, additional cleaning and inspection steps should be added according to product specifications.
10. Emphasize Product Inspection
Etching completion does not mean the processing is finished; it is still necessary to conduct inspections according to product requirements. Common inspection items include overall dimensions, hole diameters, line widths, hole spacing, flatness, burrs, surface condition, and etching depth. For precision products, equipment such as microscopes, projectors, image measuring machines, and coordinate measuring machines can be used for dimensional inspection. If the product is intended for subsequent assembly, key dimensions need to be checked in accordance with the actual assembly requirements, rather than inspecting a single dimension alone.
11. Different Products Cannot Use Identical Process Parameters
In actual production, even if two products use the same metal material, if their thickness, pattern, hole size, and precision requirements are different, identical etching parameters cannot be simply applied. For example, thin precision gaskets, metal meshes, code disks, shielding components, and flow plates have significant differences in structure and dimensional requirements. Therefore, the etching process needs to be adjusted according to the product drawings and material characteristics, gradually determining stable production conditions through samples, inspection, and parameter optimization.
12. Consider Etching During the Design Stage
The quality of etched products depends not only on the production stage but also on early design. When creating design drawings, factors such as material thickness, minimum line width, minimum hole size, hole spacing, edge structures, and undercut compensation need to be considered. If the product structure is designed entirely according to machining thinking and then directly enters etching production, some dimensions may be difficult to achieve stably. Therefore, a more reasonable approach is to match product design with the etching process and verify the manufacturability of the structure during the prototyping stage.
Conclusion
The etching process involves multiple stages, including materials, pretreatment, film application, exposure, development, etching, cleaning, and inspection, and each stage can affect the final product’s dimensions and quality. For ordinary metal parts, attention should be focused on etching uniformity and dimensional stability; for products such as micro-holes, fine lines, precision gaskets, and code disks, special attention should be given to undercut, pattern transfer, and dimensional compensation. Therefore, etching processing should not only concern whether the etching can be done but also involve overall control from material selection, pattern design, process parameters, to final inspection, in order to improve product consistency and processing stability.
Post time: Oct-10-2026
