Gate Stack Void Prevention via Oxygen Extraction
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Solution Overview
Problem
As semiconductor devices approach smaller feature sizes, challenges arise in forming reliable gate stacks without voids, which can affect device performance and manufacturing efficiency due to oxygen interference in nucleation layers during the deposition of conductive materials.
Innovation Solution
A method involving the formation of a first nucleation layer with a pre-soak step to remove oxygen, followed by a second nucleation layer and conductive material deposition to fill openings in the gate stack, preventing void formation and enhancing manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to form gate stacks at smaller feature sizes, then manufacturing process simplicity is maintained, but voids form in the gate stack due to oxygen interference in nucleation layers
Solution Approach 1:
The patent applies preliminary action by performing a pre-soak treatment on the nucleation layer before conducting the aluminum deposition process. This pre-soak step removes oxygen from the nucleation layer, preventing oxygen interference during subsequent deposition. By addressing the oxygen issue in advance, the process ensures complete filling of the gate stack without void formation, thereby improving manufacturing precision without requiring fundamentally complex deposition methods.
Solution Approach 2:
The patent extracts the harmful oxygen from the nucleation layer through a pre-soak treatment step before deposition begins. By removing oxygen from the system in advance, the harmful factor (oxygen interference) is eliminated, allowing subsequent deposition to proceed without void formation. This extraction approach resolves the contradiction by preparing the nucleation layer in a state that enables complete gate stack filling.
2Productivity
If feature sizes are reduced to increase integration density, then more components can be integrated into a given area, but void formation in gate stacks increases due to oxygen interference
Solution Approach 1:
The pre-soak treatment serves as a preliminary action that prepares the nucleation layer for small-feature-size deposition by removing oxygen. This enables the deposition process to successfully complete at reduced feature sizes without void formation, thereby maintaining reliability while achieving higher integration density through smaller dimensions.
Solution Approach 2:
The patent changes the physical-chemical state of the nucleation layer by performing a pre-soak treatment that removes oxygen. This parameter change (oxygen concentration in nucleation layer) enables successful deposition at smaller feature sizes, allowing both high integration density and gate stack quality to be achieved simultaneously.
3Manufacturing precision
If a pre-soak step is added to remove oxygen from the nucleation layer, then void formation is prevented, but manufacturing process complexity increases
Solution Approach 1:
The pre-soak step is positioned as a preliminary action that simplifies the overall manufacturing precision outcome. Although it adds one step, it prevents void formation that would otherwise require complex remediation or result in defective devices. The pre-soak enables subsequent deposition to proceed smoothly, achieving complete filling without requiring multiple complex deposition cycles or additional corrective steps.
4Productivity
If conventional deposition is performed without pre-soak treatment, then manufacturing efficiency is maintained, but oxygen interference causes voids in the gate stack
Solution Approach 1:
The pre-soak treatment extracts oxygen from the nucleation layer before deposition begins. By removing this harmful factor in advance, the process achieves both high manufacturing efficiency and high manufacturing precision. The extraction of oxygen prevents void formation, eliminating the need for rework or device rejection, thereby actually improving overall manufacturing efficiency while maintaining high precision.
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 reduces oxygen interference, prevents voids in the gate stack, and improves the operational and manufacturing efficiencies of semiconductor devices by ensuring complete filling of the gate stack without defects.
Implementation Method 1
A first nucleation layer is deposited within the first opening and over the gate dielectric, the first nucleation layer is treated to remove oxygen
Implementation Method 2
a conductive material is deposited to fill a remainder of the first opening
Data Source
AI summary
A semiconductor device and method of manufacturing are provided. In an embodiment a first nucleation layer is formed within an opening for a gate-last process. The first nucleation layer is treated in order to remove undesired oxygen by exposing the first nucleation layer to a precursor that reacts with the oxygen to form a gas. A second nucleation layer is then formed, and a remainder of the opening is filled with a bulk conductive material.