Method for forming a deep trench in a microelectronic component substrate
AssigneeSTMicroelectronics (Crolles 2) SAS
InventorsArnaud Tournier, François Leverd
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Abstract
A trench is formed in a semiconductor substrate by depositing an etch mask on the substrate having an opening, etching of the trench through the opening, and doping the walls of the trench. The etching step includes a first phase having an etch power set to etch the substrate under the etch mask, and a second phase having an etch power set smaller than the power of the first phase. Further, the doping of the walls of the trench is applied through the opening of the etch mask.
Claims18
A method for forming a trench in a semiconductor substrate around an area of a microelectronic element, wherein the geometry of said area defines properties of the microelectronic element, and wherein said area is located in a predetermined thickness of the semiconductor substrate from a surface thereof, said method comprising the deposition on said surface of the substrate of an etch mask masking said area and having an opening of access to the substrate around said area, the ion etching of said trench through said opening over a thickness of the substrate greater than the thickness of said area, and the doping of the walls of the trench, wherein the ion etching comprises:
- a first phase etching the trench over the thickness of said area, with an etch power set to etch the substrate under the etch mask;
- followed by a second phase etching the trench over the entire thickness thereof, with an etch power smaller than the power of the first phase;
- and
- the doping of the walls of the trench is applied through the opening of the etch mask.
A method, comprising:
- depositing a mask over a top surface of a substrate, said mask having an opening;
- performing a first etching of the substrate through the opening in the mask to produce a first etched region, said first etching performed at a first etching power such that the first etched region extends underneath the mask to leave a mask overhang;
- performing a second etching of the substrate through the opening in the mask to produce a second etched region below the first etched region, said second etching performed at a second etching power less than the first etching power;
- and
- doping sidewalls of the first and second etched regions through the opening in the mask, the mask overhang limiting a thickness of the doped sidewalls of the first etched region near the top surface of the substrate.
A semiconductor structure, comprising:
- a substrate including an isolating trench structure;
- the isolating trench structure comprising a first etched region having a first sidewall with a first slope and a second etched region extending below the first etched region having a second sidewall with a second slope different from the first slope;
- and
- doped regions of the first and second sidewalls, wherein the doped region of the first sidewall is tapered with a doped thickness widest at a bottom of the first etched region adjacent the second etched region and narrowest at a top of the first etched region adjacent a top surface of the substrate.
Dependencies are inferred from the claim text.