High conductance cryopump for type III gas pumping

A cryopump comprising:

• a refrigerator having first and second stages;
• a second stage cryopanel in thermal contact with the second stage of the refrigerator to condense low temperature condensing gases;
• a radiation shield surrounding the second stage cryopanel and in thermal contact with the first stage of the refrigerator;
• and
• a frontal cryopanel across an opening in the radiation shield serving as a cryopumping surface for higher condensing temperature gases, the frontal cryopanel covering an area less than 50% of the opening in the radiation shield;
• a second stage cryopanel comprising an array of baffles carrying an adsorbent, at least about 80% of the adsorbent having a direct line of sight to the radiation shield or to the opening in the radiation shield.

A cryopump comprising:

• a refrigerator having first and second stages;
• a second stage cryopanel in thermal contact with the second stage of the refrigerator to condense low temperature condensing gases;
• a radiation shield surrounding the second stage cryopanel and in thermal contact with the first stage of the refrigerator;
• and
• a frontal cryopanel across a frontal opening in the radiation shield serving as a cryopumping surface for higher condensing temperature gases;
• the second stage cryopanel comprising an array of baffles carrying an adsorbent, including baffles extending toward the frontal opening.

A cryopump comprising:

• a refrigerator having first and second stages;
• a second stage cryopanel in thermal contact with the second stage of the refrigerator to condense lower temperature condensing gases;
• and
• a radiation shield surrounding the second stage cryopanel and in thermal contact with the first stage of the refrigerator, the radiation shield comprising sides and a base closing an end of the sides, a junction of the sides and base being sloped to focus gases toward the second stage cryopanel;
• and
• a frontal cryopanel across an opening in the radiation shield serving as a cryopumping surface for higher condensing temperature gases, the frontal cryopanel covering an area greater than a projection of the second stage cryopanel but less than 50% of the opening in the radiation shield;
• the second stage cryopanel comprising:
• an array of flat baffles having edges directed toward the radiation shield;
• and
• frontal baffles angled outwardly and toward the opening in the radiation shield, the edges of the frontal baffles defining an envelope extending toward the opening of the radiation shield, the envelope having a sloped periphery;
• baffles of the second stage cryopanel carrying an adsorbent, at least about 80% of the adsorbent having a direct line of sight to the radiation shield or to the opening in the radiation shield.

A cryopump comprising:

• a refrigerator having first and second stages;
• a second stage cryopanel in thermal contact with the second stage of the refrigerator to condense low temperature condensing gases, the second stage cryopanel comprising an array of discs, the discs fanning to define a generally ball shaped envelope;
• a radiation shield surrounding the second stage cryopanel and in thermal contact with a first stage heat sink;
• and
• a frontal cryopanel across an opening in the radiation shield serving as a cryopumping surface for higher condensing temperature gases.