Wafer Container Secondary Restraint for Shock Protection
Solution Overview
Problem
Existing wafer containers are inadequate in preventing physical damage and cross-slotting of semiconductor wafers during shock events due to insufficient wafer restraint structures, which can lead to wafer dislodgement or improper alignment.
Innovation Solution
A secondary wafer restraint structure with synclinally shaped notches is interposed between primary wafer restraint members on the container door, limiting vertical movement and preventing wafers from 'jumping' out of supports or cross-slotting by engaging the wafer edges at converging surfaces when the door is sealed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only primary wafer restraint members are used, then the structure is simple, but wafers can translate too far vertically during shock events causing damage
Solution Approach 1:
The restraint system is divided into two distinct segments: primary wafer restraint members that provide initial support, and secondary wafer restraint members that provide additional vertical restraint. This segmentation allows each component to perform its specific function without requiring a single complex structure to handle all restraint needs.
Solution Approach 2:
The secondary wafer restraint members extend in the vertical dimension between the opposing primary restraint members. This adds a new dimensional element to the restraint system, creating multiple contact points that prevent excessive vertical translation of wafers during shock events.
2Reliability
If primary restraint members are spaced far apart, then wafer support coverage is improved, but wafers may become cross-slotted between adjacent restraints during shock
Solution Approach 1:
The restraint system segments the spacing between primary members by introducing secondary members in between. This creates a finer grid of restraint points that prevents wafer cross-slotting while maintaining adequate support coverage across the wafer array.
Solution Approach 2:
Secondary wafer restraint members act as intermediary elements positioned between the primary restraint members. These intermediaries provide additional contact points that prevent wafers from becoming cross-slotted during shock events, bridging the gap between primary restraint points.
3Manufacturing precision
If secondary restraint structure is added, then vertical movement is limited, but manufacturing complexity increases
Solution Approach 1:
The secondary wafer restraint members are merged with the door structure, forming an integrated assembly. This combining of functions reduces the number of separate components and simplifies manufacturing, as the secondary restraints become part of the door rather than separate add-on elements.
Solution Approach 2:
The door structure serves multiple functions: it provides structural closure for the container and simultaneously houses both the primary and secondary wafer restraint members. This multi-functionality reduces overall system complexity and streamlines manufacturing by consolidating restraint functions into the existing door component.
Data Source
AI summary
A wafer container providing improved wafer restraint during physical shock events. In embodiments of the invention, a secondary wafer restraint structure defining a plurality of notches is interposed between opposing wafer restraint members on the door of the container. The notches may be defined by one or more converging edges or surfaces meeting at a junction. The junctions are positioned so as to align with the wafer receiving portions of each opposing pair of wafer restraint member so that when the door is fully sealingly engaged with the enclosure of the container, the edge of the wafer is contacting the junction. In this position, any vertical movement of the wafer due to shock imparted to the container causes the wafer to contact the converging surfaces or edges, thereby limiting such movement. The positioning of the secondary wafer restraint structure between and proximate opposing fingers of the primary wafer restraint limits deflection of the wafer between support points and thereby further inhibits the wafer from “jumping” out of the supports and cross-slotting.