Gas phase etching system and method

A system for the dry removal of a material on a microelectronic workpiece, comprising:

• a process chamber for processing a workpiece in a non-plasma, vacuum environment, wherein the process chamber receives the workpiece with at least three exposed layers, each exposed layer having a different material composition and wherein one of the exposed layers is a target layer to be selectively removed;
• a workpiece holder arranged within the process chamber, and configured to support the workpiece;
• a temperature control system coupled to the workpiece holder, and configured to control the temperature of the workpiece holder at two or more setpoint temperatures, wherein the temperature control system includes at least one fluid control system and at least one electrical heater;
• a gas distribution system coupled to the process chamber, and arranged to supply one or more process gases containing one or more of the HF, NF3, F2, N2, or H2 into the process chamber;
• a controller operably coupled to the temperature control system, and configured to:
• (a) control the temperature of the workpiece holder at a first setpoint temperature in the range of 35 degrees C. to 100 degrees C. during the supply of one or more of process gases containing HF, NF3, F2, N2, or H2, and (b) after the supply of the process gases to adjust and control the temperature of the workpiece holder at a second setpoint temperature at or above 100 degrees C.;
• and
• wherein the controller is further configured to repeatedly perform (a) and (b) until the target layer is completely removed in a non-plasma environment without removing the remaining exposed layers, and wherein in (b), the controller is configured to adjust the temperature to the second setpoint temperature which is different from the first setpoint temperature.