Atomic Layer Etching with Dielectric-Selective Halogen Desorption
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Solution Overview
Problem
Current semiconductor fabrication techniques face challenges in achieving high etch selectivity between semiconductor and dielectric materials without plasma assistance, often resulting in damage to dielectric components and reduced pattern fidelity.
Innovation Solution
A method involving the selective adsorption of a halogen species on semiconductor portions of a substrate, followed by desorption using a second halogen species, without plasma, to etch semiconductor materials while preserving dielectric materials, utilizing specific halogen species and activation energies to ensure preferential binding and desorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma assistance is used to achieve etching of semiconductor materials, then etching speed and effectiveness are improved, but damage to dielectric components increases and selectivity decreases
Solution Approach 1:
The patent replaces plasma-based etching (a form of ion bombardment) with a purely thermal chemical process. By using temperature-controlled halogen species reactions, the method eliminates the mechanical/physical damage caused by plasma ions while maintaining effective material removal through controlled chemistry and desorption.
Solution Approach 2:
The patent changes the fundamental parameters of the etching process by operating at controlled temperatures (typically 77-300K) and using specific halogen species (Cl2, Br2, I2) with carefully controlled partial pressures. This thermal regime replaces the high-energy plasma parameters, enabling selective etching without dielectric damage.
2Productivity
If plasma assistance is used to enhance etching, then material removal efficiency is improved, but etch selectivity between semiconductor and dielectric materials deteriorates
Solution Approach 1:
The patent achieves selective etching by creating locally optimized chemical environments. Different halogen species are introduced that have specific affinities for semiconductor materials versus dielectric materials. The thermal energy distribution and gas phase chemistry are controlled to ensure reactions occur preferentially at semiconductor surfaces, providing high selectivity without plasma.
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 enables precise etching of semiconductor materials with selectivity to dielectric materials, reducing damage and improving pattern fidelity, allowing for the selective removal of semiconductor layers without affecting dielectric layers.
Implementation Method 1
providing a first activation energy to cause the first halogen species to preferentially adsorb on the semiconductor portion relative to the dielectric portion to form a first halogenated semiconductor
Implementation Method 2
providing a second activation energy to cause the second halogen species to react with the first halogenated semiconductor and cause the first halogenated semiconductor to desorb from the substrate
Data Source
AI summary
Semiconductor processing methods and apparatuses are provided. Some methods include providing a substrate to a processing chamber, the substrate having a semiconductor portion and a dielectric portion, modifying the semiconductor portion of the substrate selective to the dielectric portion of the substrate by flowing a first process gas comprising a first halogen species onto the substrate and providing a first activation energy to cause the first halogen species to preferentially adsorb on the semiconductor portion relative to the dielectric portion to form a first halogenated semiconductor, and removing the first halogenated semiconductor by flowing a second process gas comprising a second halogen species onto the substrate and providing a second activation energy, without providing a plasma, to cause the second halogen species to react with the first halogenated semiconductor and cause the first halogenated semiconductor to desorb from the substrate.