PEALD Spacer Deposition for High Etch Selectivity
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Solution Overview
Problem
Current double patterning technologies in semiconductor manufacturing result in poor, unstable, and weak masks that fail to effectively form high aspect ratio features due to inadequate etch selectivity of spacer materials relative to carbon-containing core and gap-fill materials, leading to reliability issues and device problems.
Innovation Solution
A method and apparatus for patterning substrates using negative patterning schemes, where a spacer material is deposited conformally over a core material using atomic layer deposition, with specific conditions to achieve an etch selectivity of at least 6:1, allowing the spacer to be etched at a rate at least six times faster than the carbon-containing material, thereby reducing degradation and improving mask formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition techniques are used for spacer material, then deposition process is simple, but etch selectivity of spacer relative to carbon-containing core material is insufficient
Solution Approach 1:
The patent changes the deposition parameters by using plasma-enhanced atomic layer deposition (PEALD) with specific plasma power (50-250 W), pressure (1-10 Torr), and temperature (25-150°C) conditions to deposit silicon oxide spacer material with controlled density and composition that achieves at least 6:1 etch selectivity relative to carbon-containing core material
Solution Approach 2:
The patent uses composite material approach by depositing silicon oxide spacer material with specific physical and chemical properties that provide both conformal coverage and high etch selectivity, creating a material system that simultaneously satisfies multiple requirements for mask formation stability and pattern fidelity
2Reliability
If spacer material with high etch selectivity is used, then mask stability improves, but deposition conditions become more restrictive
Solution Approach 1:
The patent optimizes deposition parameters including plasma power (50-250 W), pressure (1-10 Torr), and temperature (25-150°C) to achieve the right balance between mask stability and process ease, allowing reliable mask formation under controlled but achievable manufacturing conditions
Solution Approach 2:
The patent uses periodic plasma enhancement cycles in the ALD process, where plasma is applied in discrete pulses during the deposition sequence to modify the spacer material properties incrementally, achieving high etch selectivity through repeated controlled exposure rather than continuous processing
3Speed
If plasma power is increased to improve etch selectivity, then spacer etch rate increases, but core material degradation worsens
Solution Approach 1:
The patent applies local quality principle by creating spatial and temporal differentiation in plasma exposure - the spacer material receives targeted plasma treatment during specific ALD cycles to enhance its etch selectivity, while the carbon-containing core material is protected from excessive plasma exposure, allowing differential modification of material properties in different locations of the structure
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 approach enables the formation of stable and effective masks with minimal degradation, ensuring reliable etching of target layers and improving the efficiency and throughput of semiconductor manufacturing processes.
Implementation Method 1
exposing the substrate to an oxidant and igniting a plasma
Implementation Method 2
depositing a spacer conformally over a core material, the spacer deposited by one or more atomic layer deposition cycles
Implementation Method 3
selectively etching the spacer under conditions for etching the spacer at a rate at least six times faster than that of the core material
Data Source
AI summary
Methods and apparatuses for depositing low density spacers using atomic layer deposition for negative patterning schemes are provided herein. Methods involve one or more of: (1) exposing a substrate to a plasma for a duration less than about 300 ms in each cycle of alternating pulses of a deposition precursor and oxidizing plasma; (2) exposing the substrate to the plasma at a radio frequency power density of less than about 0.2 W/cm2; and (3) exposing the substrate to the plasma produced from a process gas having an argon to oxidant ratio of at least about 1:12.