Bake Device Substrate Holding Assembly for Uniform Heating
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Solution Overview
Problem
In the manufacture of optical devices, substrates with refractive indices greater than 1.5 tend to bow when heated above 50°C, leading to non-uniform temperature distribution and subsequent defects in resist layers during post-apply baking (PAB) and post-exposure baking (PEB).
Innovation Solution
The proposed bake apparatus includes a substrate holding assembly with shafts and extensions to support substrates, and a lid with heating elements to form a process volume. This design ensures uniform heating of substrates without bowing, using a combination of shafts, extensions, and heating elements to maintain even temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If substrates with refractive index greater than 1.5 are heated to temperatures greater than 50°C, then the baking process can be performed, but the substrates bow by about 1 mm to about 2 mm from edge to center resulting in non-uniform temperature distribution
Solution Approach 1:
The patent applies preliminary anti-action by using shafts and extensions to mechanically counteract the bowing force before it fully develops. The extensions contact the substrate edges and apply a counteracting force that prevents the substrate from bowing during heating, thereby maintaining uniform temperature distribution across the substrate surface.
Solution Approach 2:
The patent applies local quality by providing support specifically at the substrate edges through the shafts and extensions. This localized support structure targets the areas most prone to bowing (the edges) and applies differential support forces to maintain overall substrate flatness while allowing the center to be heated uniformly.
2Temperature
If substrates are heated on conventional substrate supports, then heating can be performed, but non-uniform temperature across the substrate surface results in non-uniform resist layer properties
Solution Approach 1:
The shafts and extensions are positioned to counteract substrate bowing before the heating process begins or during early heating stages. This preliminary anti-action ensures the substrate maintains contact with the heating surface uniformly, preventing temperature variations that would cause non-uniform resist layer properties during PAB and PEB processes.
Solution Approach 2:
The invention creates equipotentiality in terms of temperature distribution by preventing substrate bowing. The shafts and extensions ensure that all regions of the substrate (edge, center, and intermediate areas) remain at the same potential temperature level during heating, which directly translates to uniform resist layer properties across the entire substrate surface.
3Temperature
If substrate edges are not retained on heated substrate support due to bowing, then heating continues, but non-uniform temperature distribution occurs
Solution Approach 1:
The shafts and extensions provide localized support specifically at the substrate edges, which are the areas most prone to losing contact with the heating surface. This edge-focused support ensures that the edges remain retained on the heated substrate support throughout the heating process, maintaining uniform temperature distribution across the entire substrate including the critical edge regions.
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 apparatus achieves uniform or substantially uniform heating of substrates, preventing bowing and ensuring consistent temperature across the substrate surface. This results in improved substrate quality by maintaining uniform resist layers and patterning during PAB and PEB processes.
Implementation Method 1
heating the process volume with one or more heating elements of the bake apparatus. The heating elements heat the one or more substrates uniformly or substantially uniformly
Implementation Method 2
heating the process volume with one or more heating elements of the bake apparatus
Data Source
AI summary
Embodiments of the present disclosure relate to bake apparatuses for handling and uniform baking of substrates and methods for the handling and the uniform baking of substrates. The bake apparatuses allow the substrates to be heated to a temperature greater than 50° C. without bowing of about 1 mm to about 2 mm from the edge of the substrates to the center of the substrates. The bake apparatuses heat the substrates uniformly or substantially uniformly to improve substrate quality.