Thermal processing chamber with low temperature control

An apparatus, comprising:

• a chamber body;
• a window disposed on the chamber body;
• a chamber bottom;
• a cooling member disposed on the chamber bottom, wherein the cooling member comprises:
• a first surface;
• a second surface opposite the first surface and having a recess formed in the second surface;
• an outer surface connecting the first surface and the second surface;
• an inner surface opposite the outer surface;
• and
• one or more surfaces connecting the first surface and the inner surface, a plurality of openings formed in the one or more surfaces and in fluid communication with the recess, and wherein the one or more surfaces comprises a third surface, a first connecting surface connecting the third surface and the first surface, a fourth surface, and a second connecting surface connecting the third surface and the fourth surface;
• and
• a reflector plate disposed on the chamber bottom, wherein the reflector plate secures the cooling member to the chamber bottom.