Semiconductor Doped Region Alignment via Self-Aligned Conductive Mask
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Solution Overview
Problem
The complexity of photolithography processes in semiconductor manufacturing leads to inaccuracies in forming precisely defined mask layers, especially as feature sizes decrease, affecting the efficiency and stability of semiconductor devices.
Innovation Solution
A method involving the formation of a semiconductor structure using a conductive layer and multiple patterned mask layers, where a doped region is created through vertical and inclined doping steps, allowing for precise control of the doped region's length and alignment, thereby improving device stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to form mask layers, then semiconductor structures can be manufactured, but manufacturing precision deteriorates due to difficulties in forming precisely-defined mask layers as feature sizes decrease
Solution Approach 1:
The conductive layer serves as a self-aligned reference structure that automatically defines the positioning for subsequent mask layers. The mask layers are formed relative to the conductive layer's position, allowing the structure itself to provide the alignment reference without requiring additional photomask alignment steps, thereby improving manufacturing precision while reducing process complexity
Solution Approach 2:
The conductive layer is formed first as a preliminary structure that establishes the geometric reference framework before any mask layers are created. This preliminary action of forming the conductive layer with precise geometry enables subsequent mask layers to be defined relative to it, ensuring high precision without the difficulties of direct photomask formation at small feature sizes
2Manufacturing precision
If multiple photolithography steps are used to form precisely-defined mask layers, then alignment accuracy may improve, but device complexity increases
Solution Approach 1:
The conductive layer acts as a self-aligned reference that eliminates the need for complex multi-step photolithography alignment procedures. By using the conductive layer's physical structure as the alignment reference, the process achieves high precision with simpler steps, reducing device complexity while maintaining manufacturing precision
Solution Approach 2:
The formation process is segmented into distinct stages: first forming the conductive layer as a reference, then sequentially forming mask layers relative to it. This segmentation allows each step to be simpler and more precise, avoiding the complexity of attempting to achieve all alignments in a single photolithography process
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 and stable formation of semiconductor structures, reducing the impact of photomask and processing parameter shifts, and enhances device efficiency by ensuring accurate positioning and profile alignment.
Implementation Method 1
A doped region is formed in the substrate by a doping step using the first patterned mask layer as a mask
Implementation Method 2
A doped region is formed in the substrate by a vertical-doping step and an inclined-doping step
Data Source
AI summary
The invention provides a method for forming a semiconductor structure. A substrate is provided. A conductive layer is formed on the substrate. A first patterned mask layer is formed on the conductive layer. The conductive layer exposed by the first patterned mask layer is removed to expose a first sidewall of the conductive layer. A doped region is formed in the substrate by a doping step using the first patterned mask layer as a mask. The first patterned mask layer is removed. A second patterned mask layer is formed on the conductive layer. The conductive layer exposed by the second patterned mask layer is removed to expose a second sidewall opposite to the first sidewall of the conductive layer. The second patterned mask layer is removed.