Substrate Heat Treatment Apparatus Sagging Inhibition
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Solution Overview
Problem
Conventional substrate heat treatment apparatuses face challenges in achieving temperature uniformity for curved substrates due to sagging issues and contamination risks during the heating process, particularly in photolithographic processes, where the substrate sags between support elements and resist materials can adhere to the sealer, causing cross-contamination.
Innovation Solution
The apparatus features support devices located at the apexes of equilateral triangles or intersections of parallel and rotated imaginary lines on the heat-treating plate, with a seal device contacting the substrate's edges to create a gastight space, and exhaust bores to manage pressure and prevent sagging and contamination. This arrangement ensures uniform heating and minimizes contact between the sealer and resist materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of support elements is increased to reduce substrate sagging, then substrate flatness is improved, but the number of contact parts increases causing more particle generation
Solution Approach 1:
The support function is segmented between two types of elements: support elements that provide structural support and positioning, and suction elements that provide holding force without contact. This segmentation allows the substrate to be held flat through suction pressure distribution while minimizing contact-related particle generation.
Solution Approach 2:
A suction field acts as an intermediary between the support structure and the substrate. Instead of relying solely on multiple contact points, the suction field distributes holding force across the substrate surface, maintaining flatness while reducing direct mechanical contact and associated particle generation.
2Reliability
If the sealer contacts the edges of the substrate to seal the space, then sealing effectiveness is improved, but resist material transfers from substrate to sealer causing cross contamination
Solution Approach 1:
The sealing function is extracted from the edge-contacting sealer and relocated to the suction field. By using suction to create and maintain the sealed space without edge contact, the source of cross-contamination (sealer-substrate edge contact) is removed while preserving sealing effectiveness through negative pressure containment.
Solution Approach 2:
The sealing mechanism transitions from mechanical contact (sealer pressing against edges) to pneumatic sealing (suction field creating negative pressure). This pneumatic approach maintains the sealed space for suction operation while eliminating direct contact between the sealer and contaminated substrate edges.
3Manufacturing precision
If support elements are arranged closely to reduce sagging, then substrate flatness is improved, but device complexity increases due to more support elements
Solution Approach 1:
The support and sealing functions are merged into a single integrated structure that provides both functions through the suction field. This consolidation eliminates the need for multiple closely-spaced support elements, reducing device complexity while maintaining substrate flatness through distributed suction forces.
Solution Approach 2:
The suction elements perform multiple functions simultaneously: they provide substrate holding force, distribute pressure to maintain flatness, and create the sealed space for heating. This multi-functionality reduces the need for separate support elements, simplifying the overall device structure.
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 inhibits substrate sagging to less than 0.006 mm and maintains temperature uniformity within ±0.03°C, while preventing cross-contamination by reducing the number of support elements and ensuring the sealer does not come into contact with contaminated edge regions.
Implementation Method 1
the substrate is sucked by exhausting gas from the space through the exhaust bores
Implementation Method 2
a heat-treating plate with a heater
Implementation Method 3
the substrate can be heated uniformly
Data Source
AI summary
A heat-treating plate has support elements projecting from an upper surface thereof. The support elements are located at apexes of equilateral triangles arranged regularly and continually. The heat-treating plate and a substrate placed on the support elements form a minute space therebetween which is sealed by a sealer. The substrate is sucked by reducing the pressure in the minute space to a negative pressure through exhaust bores. Since all the distances between adjoining support elements are equal, the substrate sags in the same amount between these support elements. With such arrangement of the support elements, sagging of the substrate is inhibited efficiently by a reduced number of support elements.