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US 6,162,367 AGranted
Gas-phase silicon etching with bromine trifluoride
AssigneeCalifornia Institute of Technology
InventorsYu-Chong Tai, Xuan-Oi Wang
Life of this patent
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Abstract
An apparatus and method for gas-phase bromine trifluoride (BrF.sub.3) silicon isotropic room temperature etching system for both bulk and surface micromachining. The gas-phase BrF.sub.3 can be applied in a pulse mode and in a continuous flow mode. The etching rate in pulse mode is dependent on gas concentration, reaction pressure, pulse duration, pattern opening area and effective surface area.
Claims21
A method of etching in a micromachining process, comprising:
- obtaining a sample of a material that can be etched using bromine trifluoride;
- and
- treating said sample by contacting said sample with a gas-phase bromine trifluoride containing etchant to produce a controlled etch depth in said sample, wherein said treating comprises introducing a specific amount of the etchant into an etching chamber with said sample, leaving said etchant in said chamber for a specified time, and then introducing another specific amount of the etchant in said chamber to define a pulsed operation,
- wherein said treating comprises storing said etchant as a liquid material, converting the liquid to a gaseous phase, and introducing the gaseous phase material into the etching chamber.
1 more element
A method of etching in micromachining processes, comprising:
- obtaining a sample;
- treating said sample by contacting said sample with a gas-phase bromine trifluoride containing etchant, for a time defining a portion of a pulse train, wherein said time lasts for a specified duration;
- at the end of said time of said specified duration, stopping contacting said sample with said gas-phase etchant to define a pulsed operation;
- and
- repeating said treating for said specified duration and said stopping, to produce a desired etch depth,
- wherein said treating comprises storing said etchant as a liquid material, converting the liquid to a gaseous phase, and introducing the gaseous phase material into an etching chamber.
3 more elements
A method of etching, comprising:
- providing a sample in a chamber;
- evacuating said chamber to a specified level of evacuation;
- introducing a fixed amount of gas-phase bromine trifluoride containing etchant into said environment, said gas-phase bromine trifluoride being sourced from a gas-phase etchant source which stores a liquid bromine trifluoride and converts it to a gas-phase bromine trifluoride;
- exposing said sample to said gas-phase etchant for a specified duration to define a pulsed operation;
- removing said gas-phase etchant from said environment, wherein said introducing, exposing and removing forms one pulse of an etching process;
- and
- applying a specified number of additional pulses.
4 more elements
A method of etching a substrate, comprising:
- obtaining a substrate of a material that can be processed using semiconductor techniques;
- pre-treating said substrate with a cleaning solution which removes a native oxide from a surface of said substrate;
- using a solution including nitrogen to dry said substrate;
- placing said substrate in a sample processing chamber;
- introducing a fixed amount of gas-phase bromine trifluoride containing etchant at a determined pressure into said sample processing chamber, said gas-phase bromine trifluoride being sourced from a gas-phase etchant source which stores a liquid bromine trifluoride and converts it to a gas-phase bromine trifluoride;
- exposing said sample to said gas-phase etchant for a specified duration to define a pulsed operation;
- ending said exposing;
- and
- after said ending, exposing said sample to another pulse of exposing said sample for a specified duration.
6 more elements
An etching apparatus, comprising:
- a reaction chamber:
- a reaction pressure sensor positioned to measure a pressure of said reaction chamber;
- a vacuum subsystem positioned to evacuate said reaction chamber;
- a vapor reservoir coupled to said reaction chamber;
- a vapor pressure sensor positioned to measure a pressure of the vapor reservoir;
- a gas-phase etchant source, which stores a liquid bromine trifluoride and converts it to a gas-phase bromine trifluoride containing etchant, therein positioned to feed the gas-phase etchant into said vapor reservoir and reaction chamber;
- an etchant controller, positioned between said etchant source and said reaction chamber, operating to selectively allow the gas-phase etchant to enter said reaction chamber for a time, and then not enter, to define a pulsed operation;
- and
- a valve positioned to regulate an inflow of gas from said gas source to said vapor reservoir and from said vapor reservoir to said reaction chamber.
6 more elements
A method of etching in micromachining processes, comprising:
- obtaining a sample;
- and
- treating said sample by contacting said sample with a gas-phase bromine trifluoride containing etchant to produce a controlled etch depth, said gas-phase bromine trifluoride being sourced from a gas-phase etchant source which stores a liquid bromine trifluoride and converts it to a gas-phase bromine trifluoride,
- wherein said gas-phase bromine trifluoride containing etchant is diluted with a specified non bromine containing gas at a specified ratio and wherein said treating comprises introducing a specific amount of the etchant into a chamber with said sample, leaving said etchant in said chamber for a specified time, and then introducing another specific amount of the etchant in said chamber to define a pulsed operation.
1 more element
A method of gas-phase etching, comprising:
- obtaining a vapor reservoir and a reaction chamber which defines a pulsed operation, wherein said vapor reservoir is coupled to said reaction chamber;
- coupling a vacuum subsystem to said reaction chamber and said vapor reservoir;
- obtaining a gas-phase bromine trifluoride containing etchant source, wherein said etchant source stores a liquid phase bromine trifluoride and converts it to a gas-phase bromine trifluoride containing etchant, and wherein said source is positioned to feed the gas-phase etchant to said vapor reservoir;
- positioning a first valve between said gas-phase etchant source and said vapor reservoir;
- positioning a second valve between said vapor reservoir and said reaction chamber;
- positioning a third valve between said vacuum subsystem and said reaction chamber;
- placing a sample inside said processing chamber;
- first closing said first valve while opening said second and third valve, allowing said vacuum subsystem to evacuate said reaction chamber and said vapor reservoir;
- second closing said second valve while opening said first valve, allowing said gas-phase etchant to enter said vapor reservoir and preventing said gas-phase etchant to enter said reaction chamber;
- third closing said first valve and closing said third valve while opening said second valve, allowing said gas-phase etchant to enter said reaction chamber from said vapor reservoir;
- fourth closing said second and said third valve, isolating said gas-phase etchant within said reaction chamber for a specified duration to define a pulsed operation;
- repeating said second, third, and fourth closing in sequence, producing a desired etch depth.
9 more elements
Dependencies are inferred from the claim text.