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Integrated circuit clean room AMC online monitoring

2024/10/10

The continuous progress of semiconductor process technology, the continuous improvement of precision, the process is becoming more and more complex, not only the excellence of process equipment, there will be more new devices, more chip stacking and system innovation to improve performance, energy consumption and cost, the best way to reduce the cost is to reduce the polysilicon spacing, metal interconnection distance, circuit unit thickness and wafer material improvement. The monitoring and control of gaseous molecular pollutants (AMCs) present in clean rooms are also increasingly required.
Any airborne pollutants deposited on the wafer surface will affect the process and reduce the yield. Due to the many complex steps of the process, PPT level pollutants will greatly affect the wafer yield.

In the face of increasingly sophisticated manufacturing processes, AMC monitoring technology is also constantly upgrading, AMC online monitoring system, the internal and external pollution sources real-time monitoring, extremely high sensitivity and concentration alarm mechanism, can be timely feedback to the factory end, so as to control the release of pollutants, to ensure the yield.

In the integrated circuit industry in accordance with Moore's law of continuous development today, how to ensure the product yield in the mass production of nanoscale chips, has become the global integrated circuit industry to overcome the problem.

According to Airborne Molecular Contaminants, AMC, which are similar in size to the transistors found in today's nanoscale chips, their presence can contaminate wafer surfaces and alter the chemistry of DUV photoresist, compromising product quality.

What is AMC?

AMC refers to a class of small molecular pollutants existing in the atmosphere, mainly in gaseous form, its size is much smaller than particulate pollutants, and its main harm is to affect the yield of advanced processes.
AMC Main Sources
External air pollution:
Ambient air pollution
Traffic exhaust NOx
Industrial emissions of SO2 and NOx
Agricultural pollution escapes NH3H2S
Secondary air pollution in the factory
External air pollution:
Building materials escape
Abnormal chemical release
Clean room maintenance, maintenance and other chemicals used to escape
Boron escape in fresh air filter material
Operator breathing and other exhaust gases
Classification of AMC by SEMI, the International Semiconductor Industry Association

The impact of AMC on the process

Causes the surface hardening T-type defect of the photoresist layer
Boron and phosphorus doping is uncontrolled
As a result, the etching rate cannot be controlled, and dibutyl phthalate (DOP) is easily attached to the surface of the wafer to form silicon carbide SiC
Cause threshold voltage change, boron, boron trifluoride and other gaseous pollutants, will cause wafer surface pollution
Pollutant gases such as hydrogen fluoride, hydrogen chloride, sulfuric acid, phosphoric acid, chlorine gas, nitrogen oxides, etc., cause surface contamination of the wafer, resulting in reduced metal adhesion in metallization
The polluted gas causes the connection wire in the chip to be scrapped due to corrosion
The optical mirror on the mask and stepping device is blurred
Resulting in outages of facilities and equipment due to corrosion

AMC online monitoring system

Practice has proved that the efficiency of daily monitoring such as laboratory sampling analysis can no longer meet the requirements of major integrated circuit manufacturers for air quality control.
The AMC online monitoring system can use a set of analytical instruments to support multi-point periodic sampling analysis in the clean room, allowing users to monitor the air environment in the production workshop in real time, timely lock the area beyond SPEC, and take retesting, traceability and other measures to minimize the harm caused by AMC.