Do you know what AMC is? In fact, AMC is the abbreviation of Airborne Molecular Contamination. It is mainly defined by SEMI as four sub-items:MA (acid vapor), MB (base vapor), MC (condensed matter) and MD (dopant matter). The sources may be automobile exhaust, atmospheric ozone, factory emissions, etc. outside the clean room, or chemical solvent volatilization, etching acid gas, plastic product spillage, etc. inside the clean room. Due to the wide range of sources and the variety of pollutant items, how to effectively control them has gradually become a major problem that troubles the relevant industry.

 

Why do people start to pay attention to AMC now?

(1) The impact of AMC on the yield of semiconductor processes. In fact, related industries have begun to prevent it a long time ago, but in the past, it was only aimed at large particles. However, as the process becomes more and more sophisticated, the prevention standards have become more stringent, and the detection requirements reached the peak at the 28nm process. Not only is the volume more stringent than in the past, the AMC detection items have gradually expanded from the simple acid and alkali substances in the past to organic substances, and the monitoring of organic species has also gradually expanded from the more than ten kinds of organic species that semiconductors paid attention to in the past to new unknown organic species.

(2) Why do we need to invest in the detection of unknown substances? The reason is that the semiconductor process is divided into many stages, and different chemical substances are input in each stage. Therefore, when we want to determine the source of pollution, in addition to determining the pollution of the current process, we must also understand whether there is residual pollution in the previous process, or whether the operator is currently causing pollution from other sources. Only by accurately grasping the situation at each stage can we truly prevent the pollution source from continuing to develop.

How does the industry respond to the AMC problem?

(1) In order to gain a leading difference with other competitors, semiconductor companies have increasingly stringent requirements for comprehensive AMC testing standards. Currently, many well-known semiconductor manufacturers have also introduced such automatic monitoring equipment, because all companies understand that improving yield will be the biggest lifeline for maintaining competitive advantage.

(2) In the optoelectronics industry, the front-end LTPS process of OLED has also begun to pay attention to the detection and control of AMC. This process is very important in terms of electrical control, so the detection of AMC is also relatively important. Many large panel manufacturers have also introduced automatic monitoring equipment to improve the yield rate.

The exposure machine process and surface coating process commonly used in the panel industry will have a very sensitive reaction to AMC interference, so more precise control of AMC is required. The generation of AMC will cause a chemical reaction in the lens of the exposure machine, and then produce chemical compounds attached to the optical lens, and this situation will cause abnormal points in the process. (Light and shadow pollution)