Vapor Delivery System with Parallel Filters for PECVD
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Solution Overview
Problem
Plasma-enhanced chemical vapor deposition (PECVD) systems face challenges with filter clogging, leading to inefficient vapor precursor delivery and requiring system shutdown for filter changes, which disrupts continuous operation and affects vaporization of liquid precursors like tetraethyl orthosilicate (TEOS).
Innovation Solution
A vapor delivery system with multiple parallel paths and a control module that monitors pressure differentials to switch between filters, allowing for continuous operation by diverting vapor flow to clean paths and enabling efficient vaporization through heated conduits and valves, reducing particle incidence and maintaining system uptime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single filter is used in the vapor delivery path, then the system structure is simple, but the filter clogs over time requiring system shutdown for filter changes
Solution Approach 1:
The vapor delivery system is divided into multiple parallel paths (first path and second path), each with its own filter (first filter and second filter). This segmentation allows the system to switch between paths when filters need maintenance, enabling continuous operation without shutting down the entire system.
Solution Approach 2:
The system implements a diverter mechanism that can divert vapor flow away from a clogged filter to a clean filter path. When one filter becomes clogged, the diverter redirects the vapor flow through the other filter, effectively recovering system functionality without requiring shutdown for filter replacement.
2Productivity
If the system shuts down for filter changes, then filter maintenance is simple, but productivity decreases due to interrupted operation
Solution Approach 1:
The dual-path design with parallel filters enables continuous vapor delivery to the chamber. While one filter is in use, the other can be maintained or replaced, ensuring that the useful action of vapor deposition continues uninterrupted, thereby maintaining high productivity and system uptime.
3Reliability
If multiple parallel paths with filters are implemented, then continuous operation is maintained, but the system complexity increases
Solution Approach 1:
The diverter mechanism serves multiple functions: it directs vapor flow to the active filter path, switches between parallel paths, and enables maintenance operations. This multi-functionality reduces the need for additional specialized components, helping to manage system complexity while maintaining reliability.
4Object-affected harmful factors
If vapor is diverted away from the chamber during precursor supply, then particle deposition is reduced, but the timing control complexity increases
Solution Approach 1:
The diverter is configured to divert vapor flow away from the chamber before the precursor is supplied and to switch to the chamber path after precursor supply begins. This preliminary action prevents particles from being deposited on the chamber walls during the precursor delivery phase, reducing unwanted deposition while maintaining manageable control complexity through predetermined timing sequences.
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 system ensures minimal downtime by automatically switching to clean filters, improving vapor precursor delivery efficiency and reducing unwanted deposition, resulting in better wafer uniformity and reduced adders on processed wafers.
Implementation Method 1
a vapor supply that supplies vapor by vaporizing at least one liquid precursor in a carrier gas
Implementation Method 2
a first filter that filters the vapor flowing from the vapor supply to the chamber
Implementation Method 3
enabling efficient vaporization through heated conduits and valves
Implementation Method 4
Plasma is created in the chamber at a second time after the first time
Data Source
AI summary
A method for supplying vapor to a chamber includes providing a first diverter valve that, when open, diverts vapor away from the chamber, and a second diverter valve that, when open, supplies the vapor to the chamber; supplying a carrier gas to the chamber; after supplying the carrier gas, creating plasma in the chamber while a substrate is in the chamber; opening the first diverter valve and closing the second diverter valve; supplying the vapor by vaporizing at least one liquid precursor in a carrier gas; after a first predetermined period sufficient for the vapor to reach steady-state flow, closing the first diverter valve and opening the second diverter valve to supply the vapor to the chamber; and after a second predetermined period following the first predetermined period, opening the first diverter valve and closing the second diverter valve to stop supplying the vapor to the chamber.