Substrate Carrier Stack Purging Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Front Opening Unified Pods (FOUPs) used in semiconductor production are prone to contamination, chafing, and inefficient loading/unloading due to their design, leading to yield loss from impurities formed by outgassing reactions with ambient air, which are difficult to prevent effectively.
Innovation Solution
The development of substrate carrier stacks with improved purging structures and positioning formations that enable horizontal purging flows within the stack, using large opening cross-sections for purging channels and arc-shaped partition webs to facilitate laminar gas flow, reducing contamination and improving handling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional FOUPs are used for substrate storage and transport, then substrates can be isolated and held in a controlled environment, but substrates are still prone to contamination from outgassing reactions with ambient air, chafing from handling mechanisms, and inefficient loading/unloading operations
Solution Approach 1:
The patent applies inert atmosphere by introducing a purging gas flow (nitrogen or dry clean air) through purging channels formed by partition webs in the substrate carrier stack. This creates an inert environment that prevents outgassing components from reacting with ambient air, thereby eliminating contamination and impurity formation on substrate surfaces.
Solution Approach 2:
The patent segments the substrate carrier structure by introducing partition webs that create multiple purging channels within the carrier. This segmentation allows the purging gas flow to reach all substrates in the stack effectively, ensuring comprehensive protection against contamination while maintaining structural integrity.
2Reliability
If purging gas flow is introduced to prevent outgassing reactions, then impurity formation is reduced, but the complexity of the storage system increases due to additional gas supply infrastructure
Solution Approach 1:
The patent makes the partition webs multi-functional by having them serve both as structural support elements for substrates and as flow-guiding structures that create purging channels. This eliminates the need for separate purging channel structures, reducing system complexity while maintaining effective purging functionality.
Solution Approach 2:
The patent merges the purging channel formation function with the partition web structure. The partition webs simultaneously provide mechanical support for substrates and define the flow paths for purging gas, combining multiple functions into a single structural element to reduce overall system complexity.
3Productivity
If robot handling mechanisms are used to place wafers into FOUPs, then automated loading is achieved, but wafers are susceptible to chafing and contamination from the handling process
Solution Approach 1:
The patent extends the inert atmosphere protection to the loading/unloading process by maintaining purging gas flow in the carrier stack. This ensures that substrates remain protected from contamination even when being handled by robotic mechanisms, as the inert environment prevents reactions between outgassing components and ambient air during the handling operation.
4Quantity of substance
If multiple substrates are stacked vertically in a carrier, then storage density is improved, but purging gas flow distribution becomes more difficult and less effective
Solution Approach 1:
The patent segments the vertical stack by introducing partition webs that create multiple purging channels extending through the stack height. This segmentation allows purging gas to flow horizontally through spaces between substrates at multiple levels, ensuring effective purging of all substrates in the vertical stack and maintaining high storage density.
Solution Approach 2:
The patent introduces horizontal purging flow paths through the vertical stack by using partition webs to create channels that extend in the horizontal direction. This dimensional approach allows purging gas to effectively reach all substrates in the vertical stack without compromising storage density, as the flow moves through the horizontal spaces between stacked substrates.
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 substrate carrier stacks effectively prevent impurity formation by ensuring efficient purging of gases, reducing yield loss and enhancing the handling and storage of semiconductor wafers by minimizing contamination and chafing, thereby improving the overall processing efficiency.
Implementation Method 1
The purging gas flow serves to remove solid and gaseous impurities by the movement of the gas
Implementation Method 2
using large opening cross-sections for purging channels and arc-shaped partition webs to facilitate laminar gas flow
Data Source
AI summary
A substrate carrier stack includes substrate carriers which are stacked or stackable on each other and carry substrates within an inner accommodation space of the substrate carrier stack. The substrate carrier stack includes at least one first purging channel and at least one second purging channel, which extend vertically parallel to the inner accommodation space at opposing sides thereof, and purging structures which enable horizontal purging flows within the substrate carrier stack through spaces between substrates held by the substrate carriers. The substrate carriers each include an outer carrier frame provided with a seat to carry a substrate, wherein the outer carrier frame extends around the first and second purging channels and the inner accommodation space.