Method and apparatus for ultrasonic wet etching of silicon
AssigneeMicron Technology, Inc.
InventorsDavid R. Hembree, Salman Akram
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Abstract
Methods of forming substantially defect-free silicon structures at the submicron level by enhancing microscopic etchant concentration uniformity and reducing hydrogen bubble adhesion. Etchant mixtures are subjected to the application of ultrasonic waves. The ultrasonic waves promote cavitation that mixes the etchant mixture on a microscopic level, and also assists in promoting bubble detachment. Wetting agents are added to the etchant mixture to enhance the hydrophilicity of the silicon surfaces and thereby reduce bubble adhesion. Apparatus to carry out the method of forming silicon structures are also disclosed.
Claims10
An etching system in which to form silicon structures from silicon wafers comprising:
- an etchant mixture, wherein said mixture includes an alkaline etchant and a wetting agent;
- an etchant tank for holding the etchant mixture, wherein said etchant tank is comprised of polypropylene;
- a holder for containing silicon wafers which is freely insertable into the etchant tank;
- and
- at least one ultrasonic transducer capable of producing ultrasonic waves in the etchant mixture at frequencies in the range of about 20 to 40 kiloHertz.
Dependencies are inferred from the claim text.