Common Problems and Solutions in Semiconductor Compressed Air Treatment

Semiconductor production requires a very high degree of cleanliness of compressed air, even a little dust, oil mist or water vapor may make the chip scrapped. Therefore, in the semiconductor workshop, the treatment of compressed air is a set of interlocking projects, but there will always be various troubles in the actual operation. The following is a clear explanation of common problems and corresponding solutions one by one. The first common problem with

is that there is oil in the compressed air. Traditional air compressors rely on oil to lubricate and cool down, and there will inevitably be trace oil mist mixed into the air during operation. The semiconductor process is very sensitive to oil, and the oil film attached to the chip surface can cause short circuit or product performance problems. The solution is to get rid of the oil at the source. At this time, the water-lubricated air compressor has great advantages. It uses water instead of traditional lubricating oil to complete compression and sealing. The compressed air itself has no oil mist and oil vapor, and the risk of oil pollution is cut off from the beginning. If the traditional oil air compressor has been installed on the site, it is necessary to install a multi-stage filtration and activated carbon adsorption device at the back to intercept the oil layer by layer, but the maintenance cost will be much higher. The second common problem with

is too much moisture in the air. The temperature of compressed air will rise in the process of being squeezed, and the water vapor will become small water droplets after cooling down. If it is not handled in time, the water droplets will accumulate in the pipeline, and the corrosion equipment will also affect the product quality. The treatment method is to connect the drying equipment behind the air compressor, first condense most of the water by freezing, and then further absorb the residual trace moisture by adsorption dryer, so that the drying degree of the air reaches the level required by the semiconductor process. Special attention should be paid to the fact that if the water-lubricated air compressor is used, the water vapor carried by the air during the compression process is more than that of the ordinary air compressor, so the processing capacity of the drying equipment should be more abundant, and the drainage at the back end should also be more diligent to avoid the accumulation of water in the system. The third common problem

is the small particles in the air. Even if it is invisible to the naked eye dust, falling on the chip may cause defects. The solution is to set up multiple filtration checkpoints, from coarse filtration to fine filtration to ultra-precision filtration at the end, like a sieve, one layer is finer than the other, blocking particles of different sizes one by one. Water lubricated air compressor is also good in this regard, because it does not use oil, it will not produce sludge and metal debris mixed into the air, reducing the possibility of secondary pollution, so that the burden of the filter system is lighter. The fourth common problem

is water accumulation and corrosion in pipes. The residual moisture in the air will slowly converge into water at the low-lying parts of the pipeline, and the inner wall of the pipeline will rust over time, and rust debris will be brought to the gas point by the airflow, forming a vicious circle. The treatment method is to maintain a certain inclination angle when laying the pipeline, so that water can naturally flow to the sewage outlet, and install an automatic drain valve at the low point to drain the water regularly. If the pipeline is walking in a place where the temperature changes greatly, the pipeline should be insulated to prevent the temperature difference from causing repeated condensation of water vapor. For water-lubricated air compressor involved in the system, because the initial water content is high, this step can not be sloppy. The fifth common problem

is that the pressure is unstable or not enough. The amount of gas used by semiconductor equipment in different processes is large and small. If the air compressor fails to respond, the pressure at the end of the pipeline will be high and low, and even the equipment will not be carried. The solution is to install a large enough gas storage tank in the system as a buffer, release the gas storage tank to supplement when the gas is in peak, and slowly recharge it when the gas is in trough. At the same time, the pipeline design should be reasonable, try to use a circular layout instead of a straight line to the end, with fewer elbows and matching pipe diameters to reduce unnecessary pressure loss. The sixth common problem

is a leaking line. If the joint is not tightened, the sealing ring is aging, and the pipeline is worn out by vibration, the compressed air will run away in vain, wasting electricity and affecting the gas supply. The treatment method is to regularly use testing methods to check the leakage points, and if problems are found, fasten or replace the parts in time. The old pipes should be replaced as soon as possible.

In general, the core of semiconductor compressed air treatment is three things: to oil, to water, to dust. The water-lubricated air compressor solves the problem of oil from the source of compression. At the same time, because it does not produce sludge and metal debris, it also indirectly reduces the risk of particle pollution, making the entire purification chain easier and more reliable. As long as the equipment is selected, the pipeline is well done, and the maintenance is kept up, the compressed air can honestly meet the demanding requirements of semiconductor production.