Cryopumps are commonly cooled by compressed helium, though they may also use dry ice, liquid nitrogen, or stand-alone versions may include a built-in cryocooler. Baffles are often attached to the cold head to expand the surface area available for condensation, but these also increase the radiative heat uptake of the cryopump. Over time, the surface eventually saturates with condensate and thus the pumping speed gradually drops to zero. It will hold the trapped gases as long as it remains cold, but it will not condense fresh gases from leaks or backstreaming until it is regenerated. Saturation happens very quickly in low vacuums, so cryopumps are usually only used in high or ultrahigh vacuum systems.

The cryopump provides fast, clean pumping of all gases in the 10−3 to 10−9 Torr range. The cryopump operates on the principle that gases can be condensed and held at extremely low vapor pressures, achieving high speeds and throughputs. The cold head consists of a two-stage cold head cylinder (part of the vacuum vessel) and a drive unit displacer assembly. These together produce closed-cycle refrigeration at temperatures that range from 60 to 80K for the first-stage cold station to 10 to 20K for the second-stage cold station, typically.

Regeneration of a cryopump is the process of evaporating the trapped gases. During a regeneration cycle, the cryopump is warmed to room temperature or higher, allowing trapped gases to change from a solid state to a gaseous state and thereby be released from the cryopump through a pressure relief valve into the atmosphere.

Most production equipment utilizing a cryopump have a means to isolate the cryopump from the vacuum chamber so regeneration takes place without exposing the vacuum system to released gasses such as water vapor. Water vapor is the hardest natural element to remove from vacuum chamber walls upon exposure to the atmosphere due to monolayer formation and hydrogen bonding. Adding heat to the dry nitrogen purge-gas will speed the warm-up and reduce the regeneration time.


Busch Vacuum Pumps & Systems:
Product announcements:


Managing particle flows in process exhaust for safety and profitability

10/28/2016  Solid particles in the abatement exhaust must be properly managed, and in some cases, substantially reduced from the gas stream before it is released into the environment.

Managing hazardous process exhausts in high volume manufacturing

03/30/2016  Integrated sub-fab systems allow HVM fab operators to safely and efficiently implement new processes containing hazardous process chemicals.

Edwards launches new vacuum pumps at SEMICON China 2016

03/15/2016  Edwards announced the availability of two new vacuum pump product families at SEMICON China: the iXM Series for semiconductor etch and chemical vapor deposition (CVD) applications, and the iXL900R for fast pump down of large flat panel display (FPD) loadlock chambers.

Pfeiffer Vacuum presents innovative vacuum solutions at the trade fairs Semicon Korea and Semicon China

01/18/2016  Pfeiffer Vacuum, a global supplier of vacuum technology, will be exhibiting at the SEMICON Korea Trade Fair in Seoul from January 27 to 29 and Semicon China in Shanghai from March 15 to 17.

Cryogenic Vacuum Pumps

12/16/2015  The cryopump provides fast, clean pumping of all gases in the mid- to high-vacuum range.

Vacuum Pumps

12/11/2015  Many semiconductor manufacturing process steps require a mid- to high-level of vacuum in the process chamber to operate effectively.

ULVAC launches dry vacuum pump accessory ECO-SHOCK ES4A

09/25/2015  ULVAC, Inc. announced that it has recently developed and started selling the ECO-SHOCK ES4A, a power saving accessory for dry vacuum pumps that can reduce power consumption.

Save costs by conserving energy in the sub-fab

07/15/2015  Opportunities for cost savings abound in the “sub-fab” of semiconductor operations where the vacuum pumps and gas abatement systems reside.

Improving the reliability of dry vacuum pumps in high-k ALD processes

02/10/2015  Design features that contributed most to the improved performance include increased rotational speed, integrated rotor sleeves, and increased purge injection temperature.

Busch Vacuum Pumps and Systems joins F450C Consortium

03/04/2014  The Facilities 450mm Consortium (F450C), a partnership of nanoelectronics facility companies guiding the effort to design and build the next-generation 450mm computer chip fabrication facilities, today announced Busch Vacuum Pumps and Systems as the eleventh member company to join the consortium.