Method for measuring the depth of well
AssigneeMosel Vitelic, Inc.
InventorsJen-Te Chen, Kou-Liang Jaw
Life of this patent
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Abstract
The present invention is directed to an effective and relatively inexpensive way to measuring the depth of a well in a semiconductor device. In accordance with an aspect of the present invention, a method for measuring the depth of a well of a substrate comprises providing a substrate having a well therein and a cut through a depth of the well. The substrate is exposed to an etchant to reveal a discontinuity in a boundary at the depth of the well. The depth of the well is measured at the boundary by scanning electron microscopy (SEM) or other suitable techniques.
Claims33
A method for measuring the depth of a well of a substrate, the method comprising:
- providing a substrate having a well therein and a cut through a depth of the well;
- exposing the substrate to an etchant to reveal a discontinuity in a boundary at the depth of the well;
- and
- measuring the depth of the well at the boundary.
A method for measuring a depth of a boundary between a first conducting doped region and a second conducting doped region, the method comprising:
- using an etchant to selectively etch the first conducting doped region and the second conducting doped region to reveal a boundary therebetween, the etchant having a different selectivity between the first conducting doped region and the second conducting doped region;
- and
- measuring the depth of the boundary between the first conducting doped region and the second conducting doped region.
A method for measuring the depth of a boundary between a first n-doped region with a first doped concentration and a second n-doped region with a second doped concentration which is different from the first doped concentration, the method comprising:
- using an etchant to selectively etch the first n-doped region with the first doped concentration and the second n-doped region with the second doped concentration which is different from the first doped concentration to reveal a discontinuity at a boundary therebetween;
- and
- measuring a depth of the boundary between the first n-doped region and the second n-doped region.
An etchant having an etch rate of an n-doped region which is higher than an etch rate of a p-doped region, the etchant comprising:
- 1 molar ratio of nitric acid;
- 0.01-0.05 molar ratio of hydrofluoric acid;
- 2 molar ratio of deionized water;
- and
- 0.001-0.003 molar ratio of iodide ions.
A method for measuring depths of boundaries, the method comprising:
- using an etchant to selectively etch a p-doped region, a first n-doped region having a first n-dopant concentration, and a second n-doped region having a second n-dopant concentration which is higher than the first n-dopant concentration, to reveal a first boundary between the p-doped region and the first n-doped region, and to reveal a second boundary between the first n-doped region and the second n-doped region, wherein the etch rates are characterized as follows:
- an etch rate of the second n-doped region>
- an etch rate of the first n-doped region>
- an etch rate of the p-doped region;
- and
- measuring a depth of the first boundary and a depth of the second boundary.
Dependencies are inferred from the claim text.