Semiconductor

Some of the gases used in semiconductor applications are toxic, flammable, and otherwise dangerous to those handling them. These dangers necessitate ATEX and IECEx hazardous location approval for many products. Ashcroft and Nagano Keiki Co. Ltd. of Japan (our parent company) annually produce over 100,000 pressure transmitters and gauges designed and engineered for safe use in semiconductor industry applications.

Hydrogen is one of the most common carrier gases used in UHP gas delivery. Safely handling hydrogen requires the implementation of protective measures that mitigate the risk of fire or explosion. Preferred methods include Intrinsic Safety and Non-Sparking Approvals. One critical factor to keep in mind is the effect of hydrogen embrittlement. The stability and repeatability of pressure transmitters and gauges rely on their measuring mechanisms (directly tied to the metallurgy and their resistance to embrittlement). Ashcroft high-purity transmitters and gauges utilize high-purity austenitic 316L stainless steel, which has been shown to mitigate the effects of hydrogen embrittlement. 

The amount of pressure needed to prevent contaminants from infiltrating cleanrooms and other clean spaces is highly specific. Too little pressure results in unwanted particles entering the area, while too much pressure causes excessive air movement and wasted energy. Pressure transducers and gauges integrated into the air handling equipment must be extremely sensitive, accurate, and reliable.

The semiconductor manufacturing process involves the highly complex transformation of a blank silicon wafer into discrete microelectronic devices. A circuit design and pattern are developed, which are then etched onto the wafer. The wafers can then be broken into individual circuits to be used in electronic devices. Semiconductor manufacturing is continually challenged to increase the amount and density of the circuitry that can fit into each wafer. Wet etching uses aggressive chemicals to perform microfabrication.

The process of dry etching, including Reactive Ion Etching (RIE), is commonly used to form contact holes on silicon wafer patterns. It uses reactive gases such as fluorocarbons, oxygen, chlorine and boron trichloride. Ashing is a similar process as dry etching to remove the photoresist (light-sensitive coating) on the wafer. Plasma ashing uses oxygen or fluorine gases, and it is important to control the flow rate of these gases that require accurate pressure measurement.

The process of Chemical Vapor Deposition (CVD) in the semiconductor industry involves using a carrier gas, such as Nitrogen or Oxygen, to dilute a toxic gas, such as Phosphine or Nitrous Oxide. Semiconductor gases can be flammable, toxic and explosive, so careful selection of a pressure transducer with appropriate approvals for intrinsic safety or non-incendive locations must be made to address critical safety concerns.

Ultrapure water is treated to the highest levels of purity for all contaminant types, and deionized water has all organic particles and dissolved gases removed. Semiconductor processes such as wafer cleaning require ultrapure and deionized water to prevent contamination in the application from foreign particles creating defects and damage to the exposed wafer surfaces.