Technique for controlling trench profile in semiconductor structures
AssigneeFairchild Semiconductor Corporation
InventorsHui Chen, Qi Wang, Briant Harward, James Pan
Life of this patent
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Abstract
A method for forming a semiconductor structure includes the following steps. Trenches are formed in a semiconductor region using a masking layer such that the trenches have a first depth, a first width along their bottom, and sidewalls having a first slope. The masking layer is removed, and a bevel etch is performed to taper the sidewalls of the trenches so that the sidewalls have a second slope less than the first slope.
Claims30
A method for forming a semiconductor structure, comprising:
- forming a single masking layer on a semiconductor region;
- forming a trench in the semiconductor region using an opening in the single masking layer, the trench having a sidewall having a first slope and defining a mesa region adjacent to the trench;
- removing completely the single masking layer;
- and
- performing a bevel etch to taper the sidewall of the trench so that the sidewall has a second slope that is less than the first slope.
A method for forming a semiconductor structure, comprising:
- forming a single masking layer over a semiconductor region;
- forming an opening in the single masking layer;
- performing a first etch to form a trench in the semiconductor region through the opening in the masking layer, the trench having a sidewall having a first slope, the trench defining a mesa region adjacent the trench;
- removing completely the single masking layer;
- and
- performing a second etch to taper the sidewall of the trench such that the sidewall of the trench has a second slope that is less than the first slope, and such that the trench has a width that gradually decreases from a top portion of the trench toward a bottom portion of the trench.
A method for forming a semiconductor structure, comprising:
- forming a single masking layer on a semiconductor region;
- forming a trench in the semiconductor region using an opening in the single masking layer, the trench having a sidewall having a substantially constant first slope along a depth of the trench and defining a mesa region adjacent to the trench;
- removing completely the single masking layer;
- and
- tapering the sidewall of the trench so that the sidewall has a substantially constant second slope along the depth of the trench, the second slope being less than the first slope.
Dependencies are inferred from the claim text.