MOSFET Contact Layout Using a Single Photolithography Mask
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Solution Overview
Problem
Current technologies face challenges in scaling down the size of MOSFETs while maintaining efficiency and reducing manufacturing costs, due to the need for expensive lithography equipment and complex etching processes.
Innovation Solution
The proposed transistor structure includes a semiconductor substrate, a gate structure, a channel region, and a first conductive region, where the lengths of the source/drain regions and contact openings are precisely controlled using a single photolithography process, eliminating the need for expensive masks and complex etching technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography processes with multiple masks are used to define contact hole openings, then the alignment precision between contact holes and gate/drain/source regions can be improved, but the device complexity and manufacturing cost dramatically increase
Solution Approach 1:
The patent combines multiple photolithography masks into a single mask pattern that simultaneously defines both the contact hole openings and the gate/drain/source regions. This merging of patterning steps eliminates alignment errors between separate masks while reducing process complexity and manufacturing cost.
Solution Approach 2:
The single mask pattern serves multiple functions: it defines the contact hole openings, defines the gate/drain/source regions, and establishes their relative positions all in one step. This multi-functionality replaces the conventional multi-mask approach that required separate patterning steps for each feature.
2Area of moving object
If the minimum feature size is shrunk to scale down MOSFET dimensions, then the integration density of MOSFETs on silicon wafer is improved, but the manufacturing cost and process complexity dramatically increase
Solution Approach 1:
By merging the contact hole definition and transistor region definition into a single mask pattern, the patent enables precise scaling to smaller feature sizes without the compounding complexity of multiple alignment steps. The single patterning step maintains precision even as dimensions shrink.
Solution Approach 2:
The mask pattern creates a direct copy of the desired transistor layout including contact holes and active regions in a single step, eliminating the need for multiple sequential patterning operations that become increasingly complex at smaller scales.
3Manufacturing precision
If multiple contact mask patterns are used to define two dimension lengths of contact holes, then the manufacturing precision of contact hole dimensions is improved, but the loss of time and manufacturing cost increase
Solution Approach 1:
The patent merges the definition of contact hole dimensions and transistor region dimensions into a single mask pattern, eliminating sequential processing steps. Both dimensional definitions are created simultaneously, reducing manufacturing time while maintaining precision through the unified patterning approach.
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 approach allows for the precise control of transistor dimensions, enabling the integration of more MOSFETs within a given planar area of a silicon wafer while reducing manufacturing costs and avoiding misalignment issues.
Implementation Method 1
A mask pattern in a photolithography process is used to define the first concave
Data Source
AI summary
A transistor structure includes a semiconductor substrate, a gate structure, a channel region, and a first conductive region. The semiconductor substrate has a semiconductor surface. The gate structure is above the semiconductor surface, and a first concave is formed to reveal the gate structure. The channel region is under the semiconductor surface. The first conductive region is electrically coupled to the channel region, and a second concave is formed to reveal the first conductive region. A mask pattern in a photolithography process is used to define the first concave, and the mask pattern only defines one dimension length of the first concave.