Intersecting Structure Patterning Vertical Corner Profile
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Solution Overview
Problem
Current semiconductor patterning techniques fail to achieve vertical corner profiles in intersecting structures due to the accumulation of non-volatile by-products like SiBrxOy, which reduces physical transparency and limits etching effectiveness, especially at the corners of intersections, posing challenges for the 10N technological node and beyond.
Innovation Solution
A method involving alternating and sequential cleaning and etching processes, including a breakthrough etch, half-etch, plasma cleaning, soft-landing etch, and overetch, with controlled operating variables to achieve a vertical corner profile, utilizing gases like HBr, Cl2, SF6, CF4, and fluorine-based gases to manage residue and enhance transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If selective etching of silicon is performed using HBr plasma, then silicon etching capability is improved, but non-volatile by-products (SiBrxOy) accumulate on substrate and chamber walls, reducing physical transparency and limiting reactive ion trajectories
Solution Approach 1:
The patent implements alternating cycles of etching and cleaning processes. The etching step uses HBr plasma to remove silicon, while the cleaning step uses fluorine-based plasma to remove accumulated by-products. This periodic alternation maintains chamber transparency and prevents by-product accumulation from limiting reactive ion trajectories, thereby sustaining etching effectiveness throughout the process.
Solution Approach 2:
The patent converts the harmful non-volatile by-products (SiBrxOy) into removable residues through the cleaning process. The fluorine-based plasma reacts with the silicon-containing by-products to form volatile species that can be evacuated, transforming the accumulation problem into a controlled removal process that restores physical transparency.
2Device complexity
If conventional etching schemes are used, then etching process simplicity is maintained, but corner residue removal is ineffective and vertical corner profiles cannot be achieved
Solution Approach 1:
The patent segments the etching process into multiple distinct steps: breakthrough etch, half-etch, soft-landing etch, and overetch, with cleaning steps interspersed. Each etching step serves a specific function in achieving the vertical corner profile, and the segmentation allows precise control over corner morphology while maintaining overall process manageability.
Solution Approach 2:
The patent performs preliminary cleaning before the main etching processes to remove initial by-product accumulation. This preliminary action prevents early by-product formation from interfering with subsequent etching steps and corner profile development, ensuring that the etching process begins with optimal physical transparency.
3Productivity
If etching continues to remove silicon, then silicon material removal is improved, but by-product accumulation increases and re-deposits on substrate, further reducing transparency
Solution Approach 1:
The patent maintains continuous progress toward silicon removal by alternating etching and cleaning steps. Rather than allowing by-product accumulation to halt the etching process, the continuous alternation ensures that each etching step progresses material removal while subsequent cleaning steps restore transparency, enabling sustained etching productivity throughout the entire process sequence.
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 effectively removes non-volatile by-products from substrate corners, ensuring a vertical profile at intersections and improving the quality of patterned devices by maintaining physical transparency and enhancing etching efficiency.
Implementation Method 1
performing a plasma cleaning process on the substrate
Implementation Method 2
performing breakthrough etch and half-etch processes on the structures on the substrate
Implementation Method 3
The reactive ion trajectories become limited especially in the substrate features below the mask level
Implementation Method 4
utilizing gases like HBr, Cl2, SF6, CF4, and fluorine-based gases to manage residue and enhance transparency
Data Source
AI summary
Provided is a method of patterning structures on a substrate using an integration scheme in a patterning system, the method comprising: disposing a substrate in a processing chamber, the substrate having a plurality of structures and a pattern, the substrate including an underlying layer and a target layer, at least one structure intersecting with another structure, each intersection having an intersection angle and a corner, the integration scheme requiring a vertical corner profile at each intersection; alternatingly and sequentially etching and cleaning the substrate to transfer the pattern onto the target layer and to achieve a target vertical corner profile at each intersection; controlling selected two or more operating variables of the integration scheme in the alternating and sequential etching and cleaning operations in order to achieve target integration objectives.