Sub-micron Horizontal Tip Feature for Precise Doping
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Solution Overview
Problem
As semiconductor parts shrink, there is a need for improved accuracy and fine-tuning in the doping process to adjust electrical properties of semiconductor layers, which existing methods fail to achieve effectively.
Innovation Solution
A method is developed to create graded or tapered dopant profiles using a sub-micron horizontal tip feature, achieved by an etch process that forms a feature with a substantially vertical sidewall and a slower etch rate near the sidewall, allowing for precise control of dopant concentration beneath the feature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithographic techniques are used to define dopant regions, then the doping process can be performed, but the minimum dimension is limited and accuracy is insufficient for shrinking semiconductor parts
Solution Approach 1:
The patent segments the doping process into two independent stages: first forming a mask pattern using photolithography, then using that mask to define a tip feature through etching, and finally performing doping through the tip feature. This segmentation allows each stage to be optimized independently, achieving sub-micron doping precision without being constrained by photolithographic resolution limits.
Solution Approach 2:
The patent introduces a tip feature as an intermediary element between the mask pattern and the final doped region. The tip feature, formed by etching through the mask and underlying layers, acts as a precision template that translates the mask pattern into a sub-micron doped region, effectively decoupling the doping precision from photolithographic limitations.
2Manufacturing precision
If the etch process continues through the entire layer, then complete penetration is achieved, but the horizontal tip feature cannot be formed
Solution Approach 1:
The patent performs preliminary actions by first depositing the mask layer and forming the mask pattern before initiating the etch process. The mask pattern is pre-configured to define the desired tip feature geometry, and the etch process is then controlled to stop at the appropriate depth to preserve the horizontal tip feature while achieving sufficient penetration for doping.
Solution Approach 2:
The patent employs dynamic control of the etch process, adjusting etch parameters and duration to achieve the precise depth required for forming the horizontal tip feature. The etch process is dynamically stopped when the tip feature reaches the desired dimensions, balancing penetration depth with feature formation requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables precise dopant profile tuning, reducing the effective critical dimension size by at least a factor of two compared to existing photolithographic techniques, allowing for more accurate doping without additional time, energy, or expense.
Implementation Method 1
using an etch process to create an etch feature in the layer of tip material, the etch feature having a substantially vertical sidewall, and the etch process having a slower etch rate near the sidewall
Data Source
AI summary
A method for creating graded or tapered dopant profiles in a semiconductor layer or layers. Preferably, a sub-micron horizontal tip feature is used to control the doping of the layer beneath the feature.