Backside Wafer Support Using Gas Pressure to Prevent Sagging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate support assemblies fail to effectively retain the surface of substrates with fragile materials like glass, which can lead to profile changes such as sagging, especially when the substrates have thicknesses less than 1 millimeter, and may damage optical devices by contacting them.
Innovation Solution
A substrate support assembly comprising a lower plate and an upper plate with a retention surface, vacuum slots, arcuate extensions that can move between raised and lowered positions, and a gas nozzle to provide gas perpendicular to the substrate surface, allowing for vacuum pressure application to the exclusion zone without contacting the active areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is retained by direct contact with the support assembly, then the substrate is securely held, but the optical devices on the substrate surface may be damaged
Solution Approach 1:
The support assembly is segmented into multiple independent support points (first support structure, second support structure, third support structure) that can be selectively positioned. This allows the substrate to be held securely at specific locations while leaving the active areas with optical devices untouched, thus preventing damage while maintaining retention security.
Solution Approach 2:
Different regions of the support assembly provide different support characteristics. The support structures are positioned to provide localized support at the perimeter and corners of the substrate, while the active areas remain unsupported. This local differentiation enables secure retention without contact damage to optical devices.
2Manufacturing precision
If the substrate is made thin (less than 1mm) to reduce weight and improve device performance, then the device performance improves, but the substrate profile changes such as sagging occur
Solution Approach 1:
The support assembly uses multiple support structures positioned at strategic locations (perimeter and corners) to counteract the gravitational force causing sagging in thin substrates. By providing distributed support points, the assembly compensates for the reduced structural rigidity of thin substrates, maintaining profile control without requiring increased thickness.
3Reliability
If the substrate has fragile materials like glass to achieve desired optical properties, then the optical performance is achieved, but the substrate becomes more susceptible to profile changes and damage
Solution Approach 1:
The support assembly is designed with multiple support structures positioned in advance to provide cushioning support for fragile substrates. The distributed support points prevent stress concentration that could lead to cracking or breakage in fragile materials like glass, thereby maintaining substrate integrity without compromising mechanical strength.
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 support assembly effectively retains the substrate without contacting the optical devices, controls the substrate profile to maintain planarity within +/â0.1 mm, and compensates for sagging using pressurized gas, ensuring accurate and damage-free processing.
Implementation Method 1
providing a vacuum pressure to an exclusion zone of the substrate. The vacuum pressure is provided through the plurality of vacuum slots
Implementation Method 2
providing a gas to active areas of the substrate through a gas nozzle disposed through the body of the substrate support assembly. The gas nozzle provides the gas at a direction perpendicular to a surface of the substrate
Data Source
AI summary
Embodiments described herein provide substrate support assemblies for retaining a surface of a substrate having one or more devices disposed on one or more surfaces of the substrate without contacting the one or more devices and preventing changes in profile of the substrate. The substrate support assembly allows for control of the substrate. The substrate support assembly includes a gas nozzle disposed through a body of the substrate support assembly. The gas nozzle provides a gas to the substrate. The gas is operable to provide pressure to the substrate to reduce contact on the substrate and to control the profile of the substrate.