Silicon metallographic etch
AssigneeMotorola, Inc.
InventorsIsabelle E. Estreicher, James B. Price
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Abstract
A metallographic etch is disclosed which removes silicon at a very low rate. The removal of the silicon at a low rate means that the etch is highly controlled. Additional characteristics of the metallographic etch are that it is non-selective and it removes the silicon uniformly. Its special uses are related to an etch which is specially adapted for minimizing the Q.sub.ss charge on a silicon surface, as well as for removing work damage on wafers in which very shallow junction devices are to be formed.
Claims12
A metallographic etch for use in the manufacture of semiconductor devices for the removal of work damaged silicon material at a uniform rate of 280A .+-.1% per minute, comprising:
- a mixture of nitric acid to hydrofluoric acid having a ratio by volume of mixture lying within the range of 600:1 to 750:1 at a temperature within the range of 23.degree. to 25.degree. C.
In the manufacture of semiconductor devices for the removal of work damaged silicon wafer in a uniform and non-selective manner without texturing the surface of the silicon wafer, the process comprising the steps of:
- removing less than 3000A of work damaged silicon using an etch of nitric acid and hydrofluoric acid having a ratio by volume of mixture lying within the range of 600:1 to 750:1.
In a process for use in the manufacture of MOS devices for stabilizing the threshold voltage of such a MOS device the improvement comprising the step of:
- etching a lapped and polished wafer in which such MOS devices are built, in an etchant solution of a mixture of nitric acid and hydrofluoric acid having a ratio by volume of mixture lying within the range of 600:1 to 750:1 respectively.
In a process for use in the manufacture of shallow base junction bipolar devices the improvement comprising the step of:
- etching a lapped and polished wafer in which such bipolar devices are built in an etchant solution of a mixture of nitric acid and hydrofluoric acid having a ratio by volume of mixture lying within the range of 600:1 to 750:1, respectively.
Dependencies are inferred from the claim text.