Semiconductors are used widely throughout the electronic circuit industry. As their name indicates, they fall between an insulator that has no conductivity and a conductor with full conductivity.Inside any semiconductor processing factory, a network of stainless steel pipework will be found which transports the gases used during semiconductor production. The pipework is used to transport low concentrations of gases such as pyrophoric, which is highly flammable when in contact with air. It is also vital that gases transported in pipework are able to pass through without accumulating particulates, moisture or other contaminants.
This article discusses the different standards of the semiconductor industry and requirements needed for welding within the semiconductor industry.
Before 1993, there were no international standards on semiconductor gas lines; individual companies set their own regulations. Standard operating procedures were usually created by the contractors who installed the gas handling systems, aiming to maintain the strict purity standards set by the industry, these helped to ensure in-house welding practices were consistent. Although the existing Semiconductor Equipment and Materials International (SEMI) Standard at the time (SEMI F81-1103) mentioned orbital welding, there were no guidelines that could be applied to the entire industry. However, in 1993 two standards were released to allow consistency with welding personnel, these were named SEMI F78-0304 and SEMI F81-1103. SEMI F78-0304 covers ‘Practice for a Gas Tungsten Arc Welding of Fluid Distribution Systems in Semiconductor Manufacturing Applications’ and SEMI F81-1103 details ‘Specification for Visual Inspection and Acceptance’.
These SEMI standards now offered guidance on fabrication and included information on welding acceptance criteria to be used in quality control.
Orbital welding is the preferred method for joining the tubing and fittings used in semiconductor process gas systems. It is essential to use a smooth inner weld head to prevent the entrapment of minute particles which can disrupt and contaminate expensive devices. It is also important to avoid rough patches on the tubing’s inside diameter as this can lead to particle shredding, this has a large impact on gas purity which may be detrimental at key processing steps. It is vital to enclose joints fully, this will ensure superior gas coverage and will minimise any oxidation of the weld bead. Semiconductor pipework is often welded in cleanroom facilities; this helps to ensure cleanliness during the welding process. Orbital Fabrications currently offers four Class 6 cleanroom workstations with an additional Class 5 cleanroom for projects that require high levels of cleanliness and purity.
Orbital Fabrications has over 25 years’ experience delivering a range of services including fabrication engineering, orbital tube welding and machining services. Based in Cambridge, its team of highly skilled engineers specialise in orbital welding, manual welding and other specialist welding services. Orbital Fabrications continue to deliver quality services acting as welding specialists for the nuclear, oil & gas, pharmaceutical and energy sectors plus many more.
Orbital Fabrications continues to invest in equipment and training to ensure their engineering services meet the highest industry standards. Recent expansions to its facilities have allowed the development of its cleanroom services.
To speak to a member of the Orbital Fabrication’s team regarding any of their services, call on 01480 464 066 or contact us here.