Wafer Container Door Guide and Seal Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges with container designs for large diameter wafers, particularly 450 mm and larger, as they experience excessive container wall deflection and particulate generation due to uneven seals and dimensional changes, which can lead to contamination and damage of sensitive wafers during handling and storage.
Innovation Solution
A front opening wafer container design featuring an elastomeric gasket configured as a rectangular frame with rounded corners, sandwiched between a gasket retention frame and a door housing member, along with door guides that provide alignment assistance and reduce frictional contact, utilizing materials like polybutylene terephthalate (PBT) or Acetal for low particle generation, and a circumferential seal with a rigidizing strip to enhance sealing integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a continuous loop seal is used on the door periphery, then seal retention on rounded corners is improved, but sealing uniformity deteriorates due to insufficient tension in large straight expanses
Solution Approach 1:
The continuous loop seal is divided into multiple discrete seal segments positioned at critical locations (corners and straight expanses). Each segment is independently retained by retention features such as grooves, tabs, or adhesives, ensuring uniform sealing pressure across the entire door periphery without relying on tension from a continuous loop.
Solution Approach 2:
A retention frame or retention features are introduced as intermediary structures between the seal and the door. These retention features provide localized support and uniform pressure distribution to the seal segments, ensuring consistent sealing across both rounded corners and large straight expanses.
2Area of stationary object
If container size is increased to accommodate larger 450 mm wafers, then wafer capacity is improved, but container wall deflection and seal distortion increase
Solution Approach 1:
Reinforcement features such as ribs, stiffeners, or thicker wall sections are added locally at critical areas of the container where deflection occurs. This provides targeted structural support to maintain door-frame interface alignment and seal integrity without increasing the overall container size or weight unnecessarily.
Solution Approach 2:
The container structure incorporates composite materials or multi-layer construction combining materials with different mechanical properties. This provides enhanced rigidity and dimensional stability to the door and container walls, reducing deflection and maintaining precise alignment of the door-frame interface while accommodating larger 450 mm wafers.
3Ease of operation
If door is frequently attached and removed for wafer access, then operational flexibility is improved, but particle generation from frictional contact increases
Solution Approach 1:
The mechanical friction-based door attachment system is replaced with a magnetic attachment system. Magnets embedded in the door and door frame provide secure holding force for frequent access operations without the frictional contact that generates particles. The door can be easily attached and removed by overcoming the magnetic force, maintaining operational flexibility while eliminating particulate generation.
Solution Approach 2:
A flexible seal material with low friction coefficients is used at the door periphery. This flexible seal allows the door to be frequently attached and removed with minimal frictional contact, reducing particle generation while maintaining ease of operation. The flexible material can deform to accommodate slight misalignments during attachment.
4Strength
If metallic fasteners are used for door attachment, then structural strength is improved, but particle generation during fastener insertion and removal increases
Solution Approach 1:
Metallic fasteners are replaced with non-metallic attachment mechanisms such as magnetic attachments, snap-fit features, or friction-based retention systems. These alternatives provide sufficient door attachment strength without the particle generation associated with metallic fastener insertion and removal, meeting the requirement for particle-free environments.
Solution Approach 2:
The door attachment system uses composite materials combining magnetic properties, elastic materials, or friction-based retention features. These composite attachment mechanisms provide structural strength comparable to metallic fasteners while eliminating particle generation, as they do not involve metal-to-metal contact during attachment and removal operations.
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 solution effectively reduces particulate generation, enhances sealing consistency, and minimizes deflection of container walls, ensuring the cleanliness and integrity of larger diameter wafers by improving the door-frame interface and reducing air velocity when opening the container, thus protecting the wafers from contamination.
Implementation Method 1
A seal, generally in the form of a continuous loop of elastomeric material is fastened on the periphery of the door to provide sealing
Implementation Method 2
door guides that provide alignment assistance and reduce frictional contact
Data Source
AI summary
A wafer container that reduces or alleviates one or more of the problems associated with excessive container wall deflection due to loading and excessive particulate generation, particularly as those problems are experienced with containers for 450 mm diameter and larger wafers. The container has an enclosure and door with interlocking features to enable transfer of tension load to the door to minimize deflection of container surfaces. The container may include a gasketing arrangement compatible with the interlock feature. The container may include a removable door guide that improves centering of the door during door installation, and that is made of low particle generating material to reduce particulates.