PCB plasma etcher Introduction

• Categories:Industry News
• Author:plasma cleaning machine-surface treatment equipment-CRF plasma machine-Sing Fung Intelligent Manufacturing
• Origin:
• Time of issue:2020-11-09
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(Summary description)Traditionally, PCB manufacturers have used corrosive solvents, such as strong acids, to etch and clean holes in printed circuit boards. Many different chemicals are used to clean the holes, but all of these chemicals can cause harm to the environment and can easily harm workers.   Etching with chemical reagents:   The traditional PCB board manufacturing method is chemical etching. Some parts of the copper foil are protected by an etching inhibitor consisting of tin, tin, and lead, while the rest of the copper is etched away. The process USES an ammonia-etched solution to remove the copper, which does not corrode tin or lead, so the copper remains a "conductor" beneath the tin, or a path for electrons to travel along the entire circuit board. The quality of the chemical etching can be defined by the integrity of the copper removal that is not protected by the anticorrosion agent. The quality also refers to the straightness of the trace edge and the degree of etched bottom cutting.   Etching bottom is caused by non-directional etching of chemicals. Once downward etching occurs, lateral etching is allowed. The smaller the bottom cutting is, the better the quality will be. These base cuts are measured and called "etching factors". All the steps of the etching process are linked together, and the quality of the etching can be the result of the etching solution or the anticorrosive agent used. Chemical etching USES many harmful chemicals and is not an environmentally friendly etching process.   Use plasma for etching:   Plasma etching is an environmentally friendly etching method popular in the 1980s to remove gum residue from PCB holes. A plasma formed in a vacuum by ionizing gas particles using a radio frequency of 13.56MHz is the fourth state of matter. Plasma PCB technology can improve the quality of etching and the removal effect of through hole pollutants. As its name suggests, PCB plasma etcher is an etching technique that produces plasma under strict conditions and is used to clean the residue from drilling holes in the PCB.   To fully understand PCB etching technology, it is necessary to master the working principle of plasma etching machine. The plasma etcher is composed of two electrodes to generate RF and a ground electrode. Generally there are four gas inlets, oxygen, CF4 or some other etched gas coming into the system through these gas inlets. Depending on the etching material, the mixture of gases is required to treat the different materials. Radio frequency ionized gas particles are applied during gas entry into the system. 13.56MHz is considered as the standard frequency of plasma formation. Rf excitations excite gaseous electrons and change their state, and the machine generates high-speed plasma pulses to etch the material. In the process of chemical reaction, PCB plasma etching system will produce volatile compounds as by-products, and it usually takes little time for the plasma to clean the hole residue on the circuit board.   Plasma is also commonly used in the lead frame of the cleaning chip package. The lead frame transmits electrical signals to the outside of the package. All organic matter must be removed before it can be added to the package.   According to the type of material to be etched, the nature of the gas used and the required type of etch, there are many types of plasma etch on PCB. The working temperature and pressure also play an important role in plasma etching. Small changes in working temperature and pressure can significantly change the electron collision frequency. RIE(reactive ion etching) USES physical and chemical mechanisms to achieve unidirectional high level surface etching. Because the RIE process combines physical and chemical processes, it is faster than plasma etching alone. High-energy ion collisions strip electrons from the plasma and allow the use of positively charged plasma for surface treatment.