High performance plastics play a vital role in the semiconductor industry. Manufacturing a semiconductor is a complex process. It starts with silicon wafers and a self-contained manufacturing facility called a fab that may cost as much a several billion dollars to construct. The central part of a fab is the clean room. Dust within the clean room is carefully controlled. Even the smallest speck of duct is larger than a microcircuit and can ruin an IC. Additionally, the facility is dampened against vibration and the temperature and humidity are carefully maintained to minimize static electricity.
Integrated circuits are manufactured using processes such as photolithography, etching, cleaning, thin film deposition and polishing. It takes some 270 chemicals and gasses1 to produce an integrated circuit. Many of these are extremely corrosive: nitric acid, hydrochloric and hydrofluoric acid, and ozone to name a few. Metals will corrode when exposed to these chemicals, producing unacceptable levels of particulates and equipment failures….but there are a number of high performance plastics that perform very well in these extreme conditions.
Here is a list of the top ten performance criteria for high performance plastics in the semiconductor industry:
1. Excellent chemical resistance properties to avoid corrosion.
2. Low particle generation for better product yield.
3. Low outgassing and low moisture absorption characteristics in vacuums.
4. High temperature performance.
5. Electrical insulating properties, low dielectric constant.
6. Dimensional stability for longer part life, creep resistance.
7. Low metal ion content thus low levels of extractables in high purity chemicals.
8. Excellent machinability.
10. Low thermal conductivity.
So, how are these high performance plastics used? First, you must understand that there are many types of semiconductor processing equipment. High performance plastics are important in all phases of semiconductor manufacturing but perhaps none more than in wet benches. These machines carry out wet chemical processes such as acid etching as well as chemical rinsing and drying. Wet benches allow for maximum process purity and minimize the threat of chemical carry-over or the contamination of wafers during drying.
Watch this youtube video of a wet bench in action!
High performance plastics are used extensively in this type of equipment, plastics such as PVDF (poly-vinylidene difluoride); PP2 (polypropylene); PTFE (polytetrafluroethylene); FEP (fluorinated ethylene propylene; PFA (perfluoroalkoxy); CPVC (chlorinated polyvinyl chloride); ECTFE (ethylene chlorotrifluoroethylene) and PCTFE (polychlorotrifluoroethylene) are some of the more common. These high performance plastics are used to make tanks, fittings, screws, gaskets, spacers, housings, gaskets, wafer carrying trays, handles, hinges, sheet, tubing, and pumps. They are highly chemical resistant and stand-up to extreme environments.
Without high performance plastics, our lap tops, cellphones and wide screen TVs, indeed the information age itself, might not have been possible.
1 According to HANDBOOK OF CHEMICALS AND GASES FOR THE SEMICONDUCTOR INDUSTRY published by Wiley.
Check back soon for a continued post that focuses more specifically on the high performance plastics used in the semiconductor industry and includes property data!
Looking for more information on chemical resistance in high performance plastics? Check out our Material Guide!