Nitridation Passivation for Semiconductor Structure Oxidation Prevention
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Solution Overview
Problem
In semiconductor fabrication, the shrinking design rules lead to increased resistivity and potential shorts due to the consumption of polysilicon material in sense line contacts and interference from residue materials, which existing methods fail to adequately address.
Innovation Solution
A nitridation passivation process is implemented, involving multiple stages of dry etching, wet stripping, and nitridation to prevent oxidation and consumption of semiconductor structures, specifically targeting the silicate material and residues, thereby protecting the structure and enhancing conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If design rules are shrunk to increase memory density, then memory density is improved, but resistivity increases and shorts occur due to polysilicon material consumption
Solution Approach 1:
The patent applies preliminary nitridation treatment to the polysilicon material before it is consumed in subsequent processing steps. This pre-treatment converts the polysilicon surface to silicon nitride, which is more resistant to consumption during spacer deposition and other processing steps, thereby preserving conductivity while enabling continued scaling for higher memory density
Solution Approach 2:
The patent changes the chemical state of the polysilicon surface by converting it to silicon nitride through nitridation. This parameter change (from elemental silicon to silicon nitride) fundamentally alters the material's properties, making it resistant to consumption and preventing resistivity increase, thus maintaining reliability while allowing design rule shrinkage
2Length of moving object
If spacer material deposition is performed to increase pitch, then spacing between structures is improved, but polysilicon material is consumed leading to increased resistivity
Solution Approach 1:
The patent performs nitridation of the polysilicon surface before spacer material deposition. This preliminary action creates a protective silicon nitride layer that prevents the polysilicon from being consumed during the spacer deposition process, thereby maintaining conductivity while still achieving the required pitch increase
Solution Approach 2:
The nitridation process creates a counter-action to the harmful consumption effect. By converting the polysilicon surface to silicon nitride beforehand, the patent creates a material that is resistant to the consumption that would otherwise occur during spacer deposition, thus preventing the resistivity increase
3Object-generated harmful factors
If wet strip clean processes are used to remove residues, then cleanliness is improved, but oxidation of semiconductor structures occurs
Solution Approach 1:
The patent applies nitridation to create a protective silicon nitride surface layer before the wet strip clean processes. This preliminary protective layer prevents oxidation of the underlying polysilicon structures during the wet cleaning steps, while still allowing effective removal of residue materials
Solution Approach 2:
The silicon nitride layer created by nitridation acts as an inert protective barrier. This layer is chemically stable and resistant to oxidation, creating a protective environment for the underlying polysilicon structures during subsequent wet cleaning processes, thereby preventing oxidation while maintaining cleaning effectiveness
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
The nitridation passivation process effectively reduces sense line contact resistance by 4-15% and prevents electrical shorts by 40-80%, improving the conductivity and reliability of semiconductor devices.
Implementation Method 1
A nitridation passivation process may be performed on the semiconductor structure to prevent oxidization of the semiconductor structure
Implementation Method 2
A dry etch process may be performed on the semiconductor structure to shape the semiconductor structure
Data Source
AI summary
Methods, apparatuses, and systems related to a semiconductor nitridation passivation are described. An example method includes performing a dry etch process on a semiconductor structure on a wafer in a semiconductor fabrication process. The method further includes performing a dry strip process on the semiconductor structure. The method further includes performing a first wet strip clean process on the semiconductor. The method further includes performing a second wet strip clean process on the semiconductor. The method further includes performing a nitridation passivation on the semiconductor structure to avoid oxidization of the semiconductor structure. The method further performing a spacer material deposition on the semiconductor structure.