Method and apparatus for detecting pin-holes in a passivation layer
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorChin-Kai Liu
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Abstract
The present invention discloses a novel method and apparatus for de-etching pin-holes in a passivation layer that is deposited over a metal conductor layer on the surface of a semiconductor wafer by utilizing a substantially clear, electrically conductive film as a top electrode immersed in an electrolyte for observing under an optical microscope bubbles generated from a pin-hole on the wafer surface which functions as a bottom electrode when a DC current is flowing through the top electrode, the electrolyte and the bottom electrode such that gases in the form of bubbles are generated at the pin-hole site where metal is exposed to the electrolyte.
Claims25
A method for detecting cavities in an insulating layer deposited over a conductive layer on a semiconducting substrate comprising the steps of:
- providing a fluid reservoir constructed of an electrically conductive material,
- filling the fluid reservoir with an electrolyte,
- positioning said semiconducting substrate on a bottom surface of and in intimate contact with the reservoir such that the substrate functions as a bottom electrode,
- positioning a substantially transparent and electrically conductive film over said substrate and in said electrolyte for use as a top electrode,
- flowing a current through said top electrode, said bottom electrode and said electrolyte such that an electrolysis reaction occurs at cavities where said conductive layer is exposed and gaseous components of said electrolyte in the form of bubbles are generated for indicating locations of said cavities.
An optical microscopy method for detecting pin-holes in a passivation layer deposited over a metal layer on a pre-processed semiconductor wafer comprising the steps of:
- providing an electrolyte tank filled with an electrolyte, said tank is constructed of an electrically conductive material,
- positioning said pre-processed semiconductor wafer on the bottom surface of the electrolyte tank such that the wafer is used as a bottom electrode,
- positioning a substantially transparent and conductive film in the electrolyte and over the wafer for use as a top electrode,
- flowing a DC current through said bottom electrode, said electrolyte and said top electrode such that an electrolysis reaction occurs at the bottom of the pin-holes where the metal layer is exposed to produce bubbles of the gas components of the electrolyte to indicate the locations of the pin-holes when observed under an optical microscope.
An apparatus for detecting pin-holes in a passivation layer deposited over a metal layer on a pre-processed semiconducting wafer comprising:
- a fluid reservoir tank of an electrically conductive material for holding said wafer and an electrolyte filling said fluid reservoir tank,
- a substantially transparent and electrically conductive film for functioning as a top electrode, and
- a power source for supplying a current flowing through a bottom electrode, said electrolyte and said top electrode such that an electrolysis reaction occurs at bottoms of said pin-holes where said metal layer is exposed to produce bubbles of gas components of said electrolyte to indicate locations of said pin-holes when observed under an optical microscope.
Dependencies are inferred from the claim text.