Buffer Chamber Wafer Heating Mechanism for Batch ALD Throughput
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Solution Overview
Problem
Current batch ALD platforms face challenges in preheating wafers efficiently without significantly impacting system throughput, as conventional methods require lengthy preheating times in the process chamber, which reduces throughput for shorter processes and is not sufficient for batch processing.
Innovation Solution
A buffer chamber with a carousel and a wafer transfer robot system that allows for simultaneous preheating of wafers in a buffer chamber before transferring them to the process chamber, utilizing a heating module and a motor-indexed carousel to align support positions with slit valves, while a wafer transfer robot moves wafers between the carousel and process chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If wafers are preheated in the process chamber using conventional methods, then the wafer reaches the required temperature for high temperature processes, but the preheating time is lengthy (up to 3 minutes) which significantly reduces system throughput
Solution Approach 1:
The patent implements a dedicated preheat chamber where wafers are preheated before entering the process chamber. This preliminary heating action occurs in a separate chamber specifically designed for this function, allowing the process chamber to be ready for immediate processing without waiting for wafer preheating. The preheat chamber includes heating elements and a wafer holder positioned to receive preheated wafers, enabling continuous operation and improved throughput.
Solution Approach 2:
The system is divided into separate functional chambers: a preheat chamber dedicated to wafer heating and a process chamber for the actual ALD process. This segmentation allows independent optimization of each chamber's function and enables parallel operations where preheating occurs simultaneously with other process preparations, eliminating the bottleneck of sequential preheating in the process chamber.
2Productivity
If single wafers are heated in a separate chamber or loadlock, then preheating can occur outside the process chamber, but the single wafer loadlock cycles are too slow to meet the wafer exchange budget for batch processing
Solution Approach 1:
The patent combines multiple wafer handling functions into a single automated robot system that operates within the preheat chamber. The robot can load multiple wafers onto the preheat susceptor, perform preheating, and transfer them to the process chamber in sequence without requiring separate loadlock cycles for each wafer. This merging of functions enables batch preheating and maintains high wafer exchange rates.
Solution Approach 2:
The preheat chamber acts as an intermediary between the loadlock and the process chamber. Instead of direct single-wafer transfers, multiple wafers are loaded into the preheat chamber, preheated together, and then transferred to the process chamber. This intermediary step allows for more efficient batch processing and reduces the number of individual transfer cycles required.
3Productivity
If the process chamber is used for both processing and preheating, then the chamber can be utilized fully, but valuable processing time is lost to preheating operations
Solution Approach 1:
All preheating operations are performed in advance in the dedicated preheat chamber before wafers enter the process chamber. This preliminary action ensures that when wafers arrive at the process chamber, they are already at the required temperature, allowing the process chamber to immediately begin the ALD process without any time loss to preheating.
Solution Approach 2:
The preheating function is extracted from the process chamber and placed in a separate dedicated preheat chamber. This extraction allows the process chamber to be dedicated solely to the ALD processing function, eliminating the time conflict between preheating and processing operations and maximizing the utilization of the process chamber for value-added manufacturing.
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 solution significantly reduces non-heating time, maintaining 80% less heat loss and enabling faster wafer exchange, thus improving system throughput by preheating wafers in parallel with other transfers and allowing for efficient handling of multiple wafers in batch processing.
Implementation Method 1
At least one heating module to heat a wafer when supported by the wafer support
Data Source
AI summary
Buffer chamber including robots, a carousel and at least one heating module for use with a batch processing chamber are described. Robot configurations for rapid and repeatable movement of wafers into and out of the buffer chamber and cluster tools incorporating the buffer chambers and robots are described.