AHF Preclean Delivery for Oxide Removal Without Corrosion
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Solution Overview
Problem
The fabrication of semiconductor devices faces challenges in removing intervening materials like native silicon oxide from substrates, which can impact electrical performance and increase defects, and existing methods may cause corrosion and contamination in processing systems.
Innovation Solution
A semiconductor processing system utilizing an anhydrous hydrogen fluoride and water vapor delivery system, with temperature control and purifiers to prevent corrosion, generates hydrofluoric acid in situ on the substrate surface for effective cleaning without radical species, using a combination of sequential and simultaneous flows of AHF and water vapor to minimize system damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods are used to remove native oxides from substrates, then cleaning effectiveness is improved, but corrosion and contamination of processing systems worsens
Solution Approach 1:
The patent introduces a specially designed delivery system with heated conduits and purifiers as intermediaries between the AHF source and reaction chamber. These intermediaries prevent premature condensation and contamination of AHF, allowing effective substrate cleaning while protecting the processing system from corrosion by maintaining AHF in a controlled, anhydrous state throughout delivery.
Solution Approach 2:
The patent changes the temperature parameter along the AHF delivery path, using heated conduits to maintain AHF above its dew point and prevent condensation. This parameter change allows AHF to reach the reaction chamber in a clean, gaseous state, enabling effective substrate cleaning without introducing moisture that would cause corrosion in the processing system.
2Device complexity
If AHF is delivered through conventional pathways, then system complexity is reduced, but corrosion and contamination in the system worsens
Solution Approach 1:
The patent segments the AHF delivery system into distinct functional zones: a purifier section to remove contaminants, heated conduit sections to prevent condensation, and a controlled delivery section to the reaction chamber. This segmentation allows each section to perform its specific function optimally, protecting the overall system from corrosion while managing the complexity through modular design.
Solution Approach 2:
The patent applies preliminary action by purifying and heating AHF before it enters the main processing system. The purifier removes contaminants in advance, and the heated conduits prevent condensation before AHF reaches sensitive components. This preliminary treatment prevents corrosion and contamination downstream, addressing the harmful factors before they can affect the processing system.
3Ease of operation
If water vapor is present during AHF delivery, then system operation is simplified, but condensation and corrosion increase
Solution Approach 1:
The patent creates an inert, water-free environment for AHF delivery by using heated conduits that maintain temperatures above the dew point and purifiers that remove moisture. This inert atmosphere prevents condensation and corrosion throughout the delivery system, allowing simplified operation without introducing water vapor that would create harmful condensation and corrosion.
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 method effectively removes native oxides from substrates while mitigating corrosion and contamination in the processing system, ensuring a clean surface for further processing and prolonging the system's operational life.
Implementation Method 1
generates hydrofluoric acid in situ on the substrate surface for effective cleaning
Implementation Method 2
one or more upstream heater jackets thermally coupled to the pressure gauge, the purifier, and the first anhydrous hydrogen fluoride conduit
Data Source
AI summary
In some embodiments, a method for semiconductor processing preclean includes removing an oxide layer from a substrate using anhydrous hydrogen fluoride in combination with water vapor. A system for the preclean may be configured to separate the anhydrous hydrogen fluoride and the water vapor until they are delivered to a common volume near the substrate. Corrosion within components of the system may be limited by purification of anhydrous hydrogen fluoride, passivation of components, changing component materials, and heating components. Passivation may be achieved by filling a gas delivery component with anhydrous hydrogen fluoride and allowing the anhydrous hydrogen fluoride to remain in the gas delivery component to form a passivation layer. Consistent water vapor delivery may be achieved in part by heating components using heaters.