US 6,635,580 B1Granted

Apparatus and method for controlling wafer temperature in a plasma etcher

AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.

InventorsR. Y. Yang, T. Y. Chen

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Abstract

An apparatus for controlling wafer temperature in a plasma etcher during a plasma-on state and a method for using such apparatus are disclosed. In the apparatus, an additional temperature sensor for sensing the wafer backside temperature and a second flow control valve of a mass flow controller are utilized such that the second flow control valve may be opened to increase the flow of cooling gas through the wafer backside when a temperature rise is detected by the temperature sensor. When the wafer temperature detected is too high, i.e., higher than 65° C., the second flow control valve is opened to increase the flow of helium cooling gas from a nominal rate of 13 sccm by at least 50%. When the temperature of the wafer detected is below 65° C., the flow of the helium cooling gas can be reduced by closing the second flow control valve.

Claims8

Dependent claims

An apparatus for controlling wafer temperature in a plasma etcher comprising:

an electrostatic chuck (ESC) for holding a wafer thereon,
a first and second plurality of ventillation apertures in said ESC for flowing a cooling gas into and out of a cavity formed between said ESC and said wafer;
a gas inlet conduit for feeding a cooling gas to said cavity through said first plurality of ventialation apertures,
a gas outlet conduit for exhausting said cooling gas from said cavity through said second plurality of ventilation apertures,
a first mass flow controller in said gas inlet conduit,
a second mass flow controller in said gas outlet conduit,
a thermal sensor mounted in said ESC for sending a signal indicative of a temperature of said cooling gas in said cavity to a controller, and
a controller adadted to cause an increase in cooling gas flow when a temperature rise in the cooling gas is detected by opening said second mass flow controller.

5 more elements

Dependencies are inferred from the claim text.