Active Area Patterning With Carbon Mask for Uniform Epitaxy
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Solution Overview
Problem
The semiconductor industry faces challenges in fabricating smaller and uniform semiconductor elements, which affects yield rates and costs due to uneven active area formation in conventional methods.
Innovation Solution
A method involving a substrate with oxide, nitride, and silicon layers, where a patterned photoresist layer is formed, a mask layer is deposited, a carbon layer is coated and etched to expose the nitride layer, and an epitaxial layer is grown to form active areas, ensuring uniformity and small dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to fabricate semiconductor elements, then the manufacturing process is simpler, but the uniformity of active areas deteriorates
Solution Approach 1:
The fabrication process is segmented into multiple distinct stages: forming patterned photoresist layer, depositing mask layer, coating carbon layer, selective etching, and epitaxial growth. Each stage serves a specific function in achieving uniform active areas, with the carbon layer segmentation being particularly important for controlling etching uniformity across different regions.
Solution Approach 2:
The carbon layer is deposited and patterned before the actual etching of the active areas. This preliminary action creates a precise etching mask that defines the boundaries and ensures uniformity of the active areas. The mask layer is also deposited in advance to protect regions that should not be etched.
Solution Approach 3:
The carbon layer serves as an intermediary between the photoresist pattern and the silicon layer etching. It provides a controlled interface that enables precise and uniform etching of the active areas, acting as a mediator that transfers the pattern information while maintaining dimensional accuracy and uniformity.
2Length of moving object
If critical dimension is continuously decreased, then the semiconductor elements become smaller, but the uniformity of elements deteriorates
Solution Approach 1:
The carbon layer is applied with varying thicknesses in different regions, creating local quality variations that compensate for dimensional reductions. The etching process is locally controlled by the carbon layer pattern, ensuring that even as critical dimensions decrease, the uniformity within each local region is maintained through precise mask definition.
Solution Approach 2:
The method changes multiple parameters simultaneously: carbon layer thickness, etching conditions, and mask layer properties. By adjusting these parameters, the process maintains uniformity even as critical dimensions are reduced to smaller values, allowing scaling while preserving element uniformity.
3Manufacturing precision
If better fabrication methods are sought to improve uniformity, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The carbon layer serves multiple functions: it acts as an etching mask, defines the pattern boundaries, controls etching rate, and protects underlying layers. This multi-functionality reduces the need for separate process steps, thereby limiting the increase in device complexity while achieving improved uniformity through a single integrated 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 method enables the formation of small, uniform active areas, meeting the requirements of novel technology nodes by improving the uniformity and reducing costs associated with semiconductor manufacturing.
Implementation Method 1
growing an epitaxial layer from the top surface of the substrate in the plurality of opens to form the active areas
Implementation Method 2
performing a photolithography to transfer the photoresist layer to be a plurality of photoresist objects on the silicon layer
Implementation Method 3
etching the carbon layer, the mask layer, and the silicon layer to expose a top surface of the nitride layer
Implementation Method 4
forming a plurality of opens in the oxide layer to expose a top surface of the substrate
Data Source
AI summary
The present disclosure provides a method of preparing active areas. The method includes the operations of: receiving a substrate having an oxide layer, a nitride layer, and a silicon layer thereon; forming a patterned photoresist layer on the silicon layer; depositing a mask layer to cover a contour of the patterned photoresist layer; coating a carbon layer on the mask layer; etching the carbon layer, the mask layer, and the silicon layer to expose a top surface of the nitride layer; forming a plurality of opens in the oxide layer to expose a top surface of the substrate; and growing an epitaxial layer from the top surface of the substrate in the plurality of opens to form the active areas.