Critical dimension variation compensation across a wafer by means of local wafer temperature control

An etching system for etching a wafer of a material comprising:

• a measuring device measuring critical dimension test features along the profile of the wafer at a plurality of preset locations;
• an etching chamber receiving the wafer from said measuring device, said etching chamber having:
• a chuck supporting the wafer, and
• a plurality of heating elements disposed within said chuck, each heating element positioned adjacent to a corresponding preset location on the wafer;
• a controller coupled to said measuring device and said plurality of heating elements, said controller independently adjusting the temperatures of the heating elements during a process to reduce variation of etched features at said corresponding preset locations;
• and
• a plurality of sensors coupled to said controller, the sensors periodically measuring an average trench depth in a local area on the surface of the wafer for each preset location,
• wherein said controller computes a local etch rate for each preset location based on said measured trench depth, and said controller independently adjusts the temperatures of the heating elements during a process to reduce the variation of local etch rates among said plurality of preset locations.

An etching system for etching a wafer of a material comprising:

• a measuring device measuring critical dimension test features along the profile of the wafer at a plurality of preset locations;
• an etching chamber receiving the wafer from said measuring device, said etching chamber having:
• a chuck supporting the wafer, and
• a plurality of heating elements disposed within said chuck, each heating element positioned adjacent to a corresponding preset location on the wafer;
• a controller coupled to said measuring device and said plurality of heating elements, said controller independently adjusting the temperatures of the heating elements during a process to reduce variation of etched features at said corresponding preset locations;
• and
• a plurality of sensors coupled to said controller, the sensors periodically measuring an average trench depth in a local area on the surface of the wafer for each preset location,
• wherein said controller computes a local etch rate for each preset location based on said measured trench depth, and said controller independently adjusts the temperatures of the heating elements during a process to reduce variation of local etch rates at said corresponding preset locations,
• wherein said plurality of sensors include an interferometer.

A method for etching a wafer of a material comprising:

• measuring critical dimension test features along the profile of the wafer at a plurality of preset locations;
• heating the underside of the wafer at said plurality of locations;
• adjusting said heating during a process to reduce the variation of etched features among said plurality of preset locations;
• periodically measuring a trench depth on the surface of the wafer for each preset location;
• computing a local etch rate for each preset location based on said measured trench depth;
• and
• adjusting said heating during a process to reduce the variation of local etch rates among said plurality of preset locations and thereby reduce the variation in final trench depth across a wafer.

An apparatus for etching a wafer of a material comprising:

• means for measuring a critical dimension along the profile of the wafer at a plurality of preset locations;
• means for heating the underside of the wafer at said plurality of locations;
• means for adjusting said heating during a process to reduce variation of said critical dimensions among said plurality of preset locations;
• means for periodically measuring a trench depth on the surface of the wafer for each preset location;
• means for computing a local etch rate for each preset location based on said measured trench depth;
• and
• means for adjusting said heating during a process to reduce the variation of local etch rates among said plurality of preset locations.

An etching system for etching a wafer of a material, comprising:

• a measuring device measuring critical dimension test features along the a profile of the wafer at a plurality of preset locations;
• an etching chamber receiving the wafer from said measuring device, said etching chamber having:
• a temperature controlled chuck supporting the wafer,
• said chuck including a plurality of distinct regions filled with fluid, the fluid at each said region heated independently to a selected temperature by means of a recirculating fluid temperature control system,
• each region positioned adjacent to each preset location on the wafer;
• and
• a controller coupled to said measuring device and said temperature controlled chuck, said controller adjusting the temperature of the fluid in each region during a process to reduce the variation of etched features among said plurality of preset locations.