The microelectronics industry has used Liqui-Cel® Membrane Contactors for over 15 years to remove oxygen and carbon dioxide from DI water used in semiconductor wafer manufacturing processes. Liqui-Cel Contactors can easily remove dissolved oxygen down to 1 ppb and dissolved carbon dioxide down to 1 ppm.
Semiconductor wafers and flat panel displays go through a multi-step process where layers are photo exposed and developed. As each layer is processed, ultrapure water is required to wash the residual processing materials from the wafer. If gasses are present in the water they can deposit on the surface of the wafer and cause a defect on the wafer surface.
Additionally, EDI and CDI have become a common technology for Ion Exchange in the semiconductor industry. These technologies operate more efficiently if the dissolved CO2 is first removed from the water. Excess CO2 in the water will load the EDI and require the installation of more EDI stacks than are necessary. Additionally CO2 loading negatively impacts the silica and boron outputs of the EDI/CDI technologies.
Liqui-Cel Contactors have become the degassing standard in the microelectronic and flat panel industry because they are clean, have very low extractables, and they do not negatively impact the water quality. They also have 10 times the surface area compared to a vacuum deaerator making them compact so that they can be placed virtually anywhere in a building. Unlike vacuum towers they are modular and can be expanded to grow with changes in plant specifications. If the water volume requirements grow or the oxygen specification gets lower, additional contactors can be added to a system to meet the changing needs.
Membrane contactors have been accepted and welcomed into this industry for over 15 years.
Membrane Contactors: An Introduction To The Technology
This paper provides a good overview to Membrane Contactor technology. Principles of Membrane Contactor Operation and mass transfer principles are discussed.
Lucent Technologies Low Level Oxygen Removal
This article summarizes a case study where Liqui-Cel® Membrane deaerators are used at Lucent Technologies to remove oxygen from water to 10 ppb.
Membrane Processing for Water Treatment in the Semiconductor Industry
This paper discusses the overall UPW loop in a Semiconductor plant. Membrane Degasification is stied as being the technology of the future for deoxygenating to 1 ppb.
Meeting Water Quality Specifications for 300 mm Processing
This paper reviews historical to current UPW specifications for 300 mm processing. More specifically, the paper discusses state of the art technologies, including Liqui-Cel® Contactors, used to meet the new specifications.
UltraPure Water: Systems for Microelectronics
This article, discusses the use of Liqui-Cel® Membrane Contactors as the degassing and oxygen removal technology used in new semiconductor plants instead of older technologies such as vacuum towers.
VLSI chooses Liqui-Cel Contactors over Conventional Vacuum Tower for Deaeration
This paper describes the process and technology that VLSI evaluated for their San Antonio Texas Plant. Liqui-Cel® Contactors were chosen over vacuum deaeration for oxygen removal of < 1ppb.
Membranes for Oxygen Removal in 300mm Semiconductor Processing
This paper discusses how low oxygen specifications in 300mm semiconductor processing can be met with degasification membranes.