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US 5,296,412 AGranted
Method of heat treating semiconductor wafers by varying the pressure and temperature
AssigneesTokyo Electron Limited, Tokyo Electron Tohoku Kabushiki Kaisha
InventorTetu Ohsawa
Life of this patent
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Abstract
A wafer boat on which semiconductor wafers are placed is inserted into a process tube, and a process gas is supplied into the process tube to perform heat treating. In this case, prior to the heat treating, the process tube is evacuated to have a pressure lower than a pressure in the heat treating while a temperature in the process tube is kept to be higher than a temperature in the heat treating. After the heat treating is performed, the process tube is purged with an N.sub.2 gas.
Claims15
A heat-treating method comprising:
- a step of inserting an object to be processed into a process tube;
- a heat-treating step of supplying a process gas into said process tube to perform heat treating;
- and
- a step of evacuating said process tube such that a pressure in said process tube is set to be lower than a pressure in the heat-treating step while a temperature in said process tube is kept to be higher than a temperature in the heat treating prior to the heat-treating step.
1 more element
A heat-treating method comprising:
- a step of inserting an object to be processed into a process tube;
- a heat-treating step of supplying a process gas into said process tube to perform heat treating;
- a first evacuating step of evacuating said process tube such that a pressure in said process tube is set to be lower than a pressure in the heat-treating step while a temperature in said process tube is kept to be higher than a temperature in the heat treating prior to the heat-treating step;
- a second evacuating step of evacuating said process tube after the heat-treating step;
- and
- a step of purging said process tube with a gas.
3 more elements
Dependencies are inferred from the claim text.