Tungsten Gate ALD Boron Concentration Control
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing metal gate structures with high-k dielectric materials, particularly in achieving reliable and durable tungsten layers with low boron concentration for advanced nanometer technology nodes, as existing methods can result in high boron concentrations that lead to damage during chemical mechanical polishing (CMP) operations.
Innovation Solution
The method involves using atomic layer deposition (ALD) to form tungsten layers with a controlled boron concentration by adjusting the flow ratio of boron-containing gases and dilute gases, reducing the boron concentration to a range of 1-27 atomic%, and optionally using silicon-containing gases to further minimize boron content, thereby enhancing the durability of the tungsten layers against CMP operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form tungsten layers with high-k dielectric materials, then the metal gate structure can be manufactured, but the boron concentration becomes too high causing damage during CMP operations
Solution Approach 1:
The patent applies parameter changes by precisely controlling the flow ratio of boron-containing gases and dilute gases during ALD processing. By adjusting the boron precursor flow rate and using dilute gases, the method reduces boron concentration in the tungsten layer to 1-27 atomic%, preventing CMP damage while maintaining reliable metal gate structure formation.
2Productivity
If boron-containing gases are used during tungsten deposition, then the deposition process can proceed, but the boron concentration increases leading to CMP damage
Solution Approach 1:
The patent maintains deposition efficiency by optimizing the flow ratio parameters of boron-containing gases and dilute gases during ALD. By carefully controlling these gas flow parameters, the process achieves adequate deposition rates while limiting boron concentration to 1-27 atomic%, preventing harmful effects during subsequent CMP operations.
Solution Approach 2:
The patent uses dilute gases as an intermediary substance during the deposition process. The dilute gas acts as a mediator that allows the deposition to proceed while diluting and controlling the boron precursor introduction, thereby maintaining productivity while reducing boron concentration to acceptable levels.
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 results in tungsten layers with reduced boron concentration, improving the reliability and durability of semiconductor devices by preventing damage during CMP and ensuring consistent performance.
Implementation Method 1
a tungsten layer on the seed layer by supplying a tungsten containing gas
Data Source
AI summary
In a method of manufacturing a tungsten layer by an atomic layer deposition, a seed layer on an underlying layer is formed on a substrate by supplying a boron containing gas and a dilute gas, and a tungsten layer is formed on the seed layer by supplying a tungsten containing gas. A flow ratio of a flow amount of the boron containing gas to a total flow amount of the boron containing gas and the dilute gas is in a range from 1/21 to 1/4.