Silicon Oxide Spacer Profile Control via ALD
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Solution Overview
Problem
Current multiple patterning techniques in semiconductor fabrication face challenges in controlling the slope and profile of silicon oxide spacers, particularly at pitches less than 45 nm, leading to mechanical deformation, pattern shift, and profile distortion, which can degrade device performance and increase processing costs.
Innovation Solution
The method involves depositing silicon oxide spacer layers using atomic layer deposition (ALD) with varying oxidation conditions, including different oxidation times, RF power, and substrate temperatures, to control the slope of the spacers, allowing for the formation of spacers with positive, negative, or vertical profiles without the need for separate deposition and etch chambers, thereby reducing processing time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional multiple patterning techniques are used to pattern small features, then feature size scaling is enabled, but the slope and profile of silicon oxide spacers cannot be controlled, leading to mechanical deformation and pattern distortion
Solution Approach 1:
The patent applies parameter changes by varying oxidation conditions (temperature, time, RF power) during ALD deposition to control the slope and profile of silicon oxide spacers. Different oxidation parameters produce different stress states in the deposited film, enabling precise control over spacer morphology without requiring additional process steps or equipment.
2Productivity
If separate deposition and etch chambers are used, then deposition quality is maintained, but processing time increases and throughput decreases
Solution Approach 1:
The patent merges deposition and etch operations into a single chamber system. The ALD deposition process for silicon oxide spacers is performed in the same chamber where subsequent etching occurs, eliminating vacuum breaks and intermediate handling steps while maintaining deposition quality through controlled plasma-based oxidation.
Solution Approach 2:
The patent enables continuous processing by performing ALD deposition and etching operations in sequence within the same chamber without breaking vacuum. This continuous action eliminates idle time between operations and maintains process integrity, thereby increasing throughput while preserving material quality.
3Loss of time
If multiple vacuum breaks are introduced, then chamber maintenance is simplified, but processing time increases and costs increase
Solution Approach 1:
The patent eliminates unnecessary vacuum breaks by performing multiple ALD deposition cycles and etching operations in continuous sequence within the same chamber. This continuous operation reduces processing time and eliminates repeated vacuum pumping cycles, directly addressing the time loss while simplifying chamber maintenance requirements.
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 controls the slope of silicon oxide spacers, improving their mechanical stability and reducing pattern distortion, while integrating etch and ALD operations in a single chamber minimizes vacuum breaks and processing steps, enhancing throughput and reducing costs.
Implementation Method 1
depositing, in a plasma chamber, a first thickness of a silicon oxide spacer layer by atomic layer deposition (ALD) on a substrate
Implementation Method 2
exposing the substrate to plasma of an oxidant under a first oxidation condition
Implementation Method 3
etching, in the plasma chamber, the patterned core material to form a plurality of spacers from the silicon oxide spacer layer
Data Source
AI summary
Methods and apparatuses for spacer profile control using atomic layer deposition (ALD) in multi-patterning processes are described herein. A silicon oxide spacer is deposited over a patterned core material and a target layer of a substrate in a multi-patterning scheme. A first thickness of the silicon oxide spacer is deposited by multiple ALD cycles under a first oxidation condition that includes an oxidation time, a plasma power, and a substrate temperature. A second thickness of the silicon oxide spacer is deposited by multiple ALD cycles under a second oxidation condition, where the second oxidation condition is different than the first oxidation condition by one or more parameters. After etching the patterned core material, a resulting profile of the silicon oxide spacer is dependent at least in part on the first and second oxidation conditions.