Metal Gate Transistor Diffusion Barrier Cleaning
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Solution Overview
Problem
Conventional cleaning processes for diffusion barriers in metal-gate transistors often form metal hump defects due to interaction with metallic materials, leading to particle formation that worsens with multiple metal gate layers.
Innovation Solution
A method involving a first solution with a surfactant at critical micelle concentration to remove organic residues, followed by a second solution with physical force to remove particles, both substantially free from interacting with the diffusion barrier, thereby preventing particle formation and reducing metal hump defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning processes are used on diffusion barriers, then cleaning effectiveness is improved, but metal hump defects and particle formation increase
Solution Approach 1:
The patent introduces a two-step cleaning process where the first solution (surfactant-based) acts as an intermediary to remove organic residues without directly attacking the metal gate layer. This intermediary approach allows subsequent cleaning steps to remove particles without causing metal hump defects, as the surfactant solution prepares the surface by removing organics that would otherwise interfere with particle removal and prevent direct chemical interaction between harsh cleaners and the metal gate.
Solution Approach 2:
The cleaning process is segmented into two distinct steps: first removing organic residues with a surfactant solution, then removing particles with a second solution. This segmentation allows each step to be optimized for its specific function without compromising the metal gate layer, preventing metal hump defects while maintaining cleaning effectiveness.
2Reliability
If multiple metal gate layers are deposited, then device performance is improved, but particle formation increases
Solution Approach 1:
The patent applies preliminary cleaning actions (removing organic residues first) before depositing metal gate layers. This preliminary removal of organic contaminants prevents particle formation during subsequent metal layer deposition, allowing multiple layers to be deposited without accumulating particles that would degrade device performance.
3Manufacturing precision
If diffusion barrier is cleaned thoroughly, then particle removal is improved, but interaction with diffusion barrier causes damage
Solution Approach 1:
The surfactant-based first solution serves as an intermediary that removes organic residues without directly interacting with or damaging the diffusion barrier. This intermediary step enables subsequent particle removal steps to be performed without the risk of diffusion barrier damage, as the organic layer has already been removed and the surface is prepared for gentle particle removal.
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
Effectively cleans the diffusion barrier without interacting with it, reducing metal hump defects and enabling smoother deposition of the metal gate layer, improving transistor performance.
Implementation Method 1
cleaning the diffusion barrier with a first solution including at least one surfactant, the amount of the surfactant of the first solution being about a critical micelle concentration (CMC) or more
Implementation Method 2
The second solution has a physical force to remove particles over the diffusion barrier
Data Source
AI summary
A method for cleaning a diffusion barrier over a gate dielectric of a metal-gate transistor over a substrate is provided. The method includes cleaning the diffusion barrier with a first solution including at least one surfactant. The amount of the surfactant of the first solution is about a critical micelle concentration (CMC) or more. The diffusion barrier is cleaned with a second solution. The second solution has a physical force to remove particles over the diffusion barrier. The second solution is substantially free from interacting with the diffusion barrier.