Stable and precise control of a processing system's vacuum pressure is critical for high-yield semiconductor device fabrication. Processes such as SAPCVD, LPCVD and etch exhibit optimal behavior at well-defined process pressures and it is critical to maintain and transition process pressures in a well-controlled, stable manner. Similarly, advanced processes such as ALD must have tight control over system pressures during gas switching steps. The required vacuum pressure control in these and other semiconductor unit processes is accomplished using closed-loop control for a number of variables that affect the vacuum process.

The importance of cleanliness cannot be overstated in the semiconductor industry. A single speck of dust can degrade the quality and performance of the semiconductor. This is a high-priority concern for manufacturers given the increasing complexity and capability of the semiconductor in a wide range of industries. Clean room designs and vacuum systems have thus been adapted keeping the purity concern in mind.Semiconductor vacuum systems, in particular, are used at various stages of manufacturing with the aim to:

Reduce impurities to prevent contamination

Lower the pressure to facilitate the uniformity of wafer placement

Lower the temperature to prevent wafer deformation

Here are some key ways in which vacuum technology is used in the semiconductor industry:

Deposition Processes 

Vacuum is essential for various deposition processes used in semiconductor manufacturing, such as chemical vapour deposition (CVD) and physical vapour deposition (PVD). These processes involve depositing thin layers of materials onto silicon wafers to create integrated circuits and other semiconductor components. A vacuum environment ensures precise control over the material deposition and reduces contamination from air molecules.

Etching 

Vacuum is also employed in the etching processes used to remove specific areas of materials from semiconductor wafers. Dry etching methods, such as plasma etching, often use low-pressure environments to create highly anisotropic etching profiles, enabling the creation of intricate patterns and features.

Ion Implantation

Ion implantation is a critical step in semiconductor manufacturing, where ions of specific elements are embedded into the silicon wafer to modify its electrical properties. This process is carried out in a vacuum to ensure precise control over ion trajectories and implantation depths.

Wafer Handling and Transfer

Vacuum technology is used for handling and transferring silicon wafers within the cleanroom environment to prevent contamination. Vacuum robotic arms and wafer handling tools are designed to transport wafers without contact, ensuring the utmost cleanliness.

Rapid Thermal Processing (RTP)

In RTP, semiconductor wafers are subjected to high temperatures in a controlled environment. Vacuum or low-pressure conditions can be used to prevent oxidation of the wafers at elevated temperatures, allowing for precise thermal treatments without introducing impurities.

Leak Testing

Vacuum technology is used to check the hermetic sealing of semiconductor packages and other components. Ensuring that no leaks are present is crucial for maintaining the integrity and reliability of semiconductor devices.

Vacuum Pumps

High-quality vacuum pumps are essential for maintaining the desired vacuum levels in various semiconductor manufacturing tools and chambers. 

Cleanroom Environments 

Cleanrooms in the semiconductor industry are maintained under controlled atmospheric conditions, including low levels of airborne particles and contaminants. Maintaining a vacuum or controlled pressure within these cleanrooms helps to minimise impurities and maintain the cleanliness required for semiconductor fabrication.