What Is The Etching Process?

What Is The Etching Process – Ultrasonic Coating Systems – Cheersonic

Etching is a technique that uses chemical strong acid etching, mechanical polishing or electrochemical electrolysis to treat the surface of objects. Apart from enhancing the aesthetics, it also increases the added value of the object. From traditional metal processing to high-tech semiconductor manufacturing, etching technology is within the scope of application.

Etching process

Depending on the type of metal, the etching process will be different, but the general etching process is as follows: metal etching plate → cleaning and degreasing → water washing → drying → film or screen printing ink → drying → exposure drawing → development → washing and drying → etching → stripping Film→drying→inspection→finished product packaging.

1. Cleaning process before metal etching:
The process before etching of stainless steel or other metals is cleaning, the main function is to remove dirt, dust, oil stains, etc. on the surface of the material. The cleaning process is the key to ensure that the subsequent film or screen printing ink has good adhesion to the metal surface. Therefore, the oil and oxide film on the metal etched surface must be completely removed. Degreasing should be determined according to the oil contamination of the workpiece. It is best to conduct electric degreasing before screen printing ink to ensure degreasing effect. In addition to the oxide film, the best etching solution should be selected according to the metal type and film thickness to ensure the surface is clean. Must be dry before screen printing. If there is moisture.

2. Paste dry film or silk-screen photosensitive adhesive layer:
According to the actual product material, thickness, and the exact width of the graphic, it is determined to use dry film or wet film screen printing. For products with different thicknesses, factors such as the etching processing time required for the product pattern should be considered when applying the photosensitive layer. Thicker or thinner photoresist layers can be produced with good coverage and high definition patterns produced by metal etching.

3. Drying:
After the film or roll screen printing ink is completed, the photoresist layer needs to be thoroughly dried in preparation for the exposure process. At the same time, it is necessary to ensure that the surface is clean and free from sticking and impurities.

4. Exposure:
This process is an important process for metal etching, and the exposure energy will be considered according to the thickness and precision of the product material. This is also the embodiment of the technical capabilities of etching processing enterprises. The exposure process determines whether etching can ensure better dimensional control accuracy and other requirements.

5. Development:
After exposing the photosensitive adhesive layer on the surface of the metal etching plate, the patterned adhesive layer is cured after exposure. After that, the unwanted parts of the pattern, that is, the parts that need to be etched, are exposed. The development process also determines whether the final size of the product can meet the requirements. This process will completely remove the unwanted photoresist layer on the product.

6. Etching or etching process:
After the product prefabrication process is completed, the chemical solution will be etched. This process determines whether the final product is qualified or not. This process involves parameters such as the concentration, temperature, pressure, and speed of the etching solution. The quality of the product needs to be determined by these parameters together.

7. Remove:
The surface of the etched product is still covered with a layer of photosensitive adhesive, and the photosensitive adhesive layer on the surface of the etched product needs to be removed. Since the photosensitive adhesive layer is an acidic substance, the acid-base neutralization method is mostly used for swelling. After overflow cleaning and ultrasonic cleaning, the photosensitive adhesive layer on the surface is removed to prevent the photosensitive adhesive from remaining.

8. Detection:
After the film is taken, the follow-up is testing, packaging, and the final product is confirmed to meet its specifications.

Precautions in the etching process

1. Reduce side corrosion and protruding edges, and improve the metal etching processing coefficient: Generally, the longer the printed board is in the metal etching solution, the more serious the side etching. Undercuts seriously affect the accuracy of printed lines, and severe undercuts will not be able to make thin lines. The etch factor increases as undercuts and edges decrease. A high etch factor indicates the ability to maintain fine lines and etch lines close to the size of the original image. Whether the plating resist is tin-lead, tin, tin-nickel, or nickel, etc., excessively protruding edges can cause wire shorts. Since the protruding edge is easily broken, a bridge is formed between the two points of the wire.

2. Improve the consistency of etching processing rate between plates: in continuous plate etching, the more consistent the metal etching processing rate is, the more uniform the etching plate can be obtained. In order to always maintain the best etching state during the pre-etching process, it is necessary to choose an etching solution that is easy to regenerate and compensate, and the etching rate is easy to control. Select technologies and equipment that provide constant operating conditions and automatically control various solution parameters. It can be realized by controlling the amount of dissolved copper, PH value, solution concentration, temperature, and uniformity of solution flow.

3. Improve the uniformity of metal etching processing speed on the entire board surface: The etching uniformity of the upper and lower sides of the board and each part of the board surface is determined by the uniformity of the flow rate of the metal etching solution on the board surface. During the etching process, the etching rates of the upper and lower plates are often inconsistent. The etch rate of the lower surface is higher than that of the upper surface. The etching reaction is weakened due to the accumulation of the solution on the surface of the upper plate. The uneven etching of the upper and lower plates can be solved by adjusting the injection pressure of the upper and lower nozzles. Using a spray system, oscillating the nozzle, can further improve the uniformity of the entire surface of the board by making the spray pressure at the center and edge of the board different.

Advantages of the etching process

Because the metal etching process is etched by chemical solution.
1. Maintain a high degree of consistency with raw materials. It does not change the properties of the material, the stress of the material, and the hardness, tensile strength, yield strength and ductility of the material. The basic processing technology is etched in the atomized state in the equipment, and there is no obvious pressure on the surface.
2. No glitches. In the process of product processing, there is no pressing force in the whole process, and there will be no curling, bumping and pressing points.
3. It can cooperate with the post-process stamping to complete the personalized molding action of the product, and can use the hanging point method for full-page electroplating, bonding, electrophoresis, blackening, etc., which is more cost-effective.
4. It can also cope with miniaturization and diversification, with short cycle and low cost.

Etching processing applications

1. The field of consumer electronics
2. Filtration and separation technology
3. Aerospace
4. Medical equipment
5. Precision machinery
6. Cars
7. High-end crafts

Source: Mechanical Design Resource Sharing Network

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.