Deformable Buffer Chuck for Substrate Flatness in Spin Coating
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Solution Overview
Problem
As semiconductor devices become increasingly integrated, issues such as non-uniform substrate flatness lead to performance degradation, including coating thickness non-uniformity, exposure focus errors, undesired alignment, overlay misalignment, bonding non-uniformity, and critical dimension inconsistencies.
Innovation Solution
A chuck design incorporating a deformable buffer portion made of a polymer and non-Newtonian fluid, which can restore after applying force, ensuring improved substrate flatness during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid chuck structure is used to maintain structural stability, then the chuck can provide strong support, but the substrate flatness deteriorates due to inability to compensate for deformations
Solution Approach 1:
The patent changes the physical parameters of the chuck structure by incorporating a buffer portion made of elastomeric material with specific hardness (Shore A 20-40) and thickness (0.5-5mm). This buffer portion can elastically deform under vacuum pressure to compensate for substrate warpage, while the rigid base portion maintains overall structural stability. The elastomeric material's ability to undergo reversible deformation allows the chuck to adapt to different substrate flatness conditions.
Solution Approach 2:
The chuck is designed as a composite structure combining rigid base portion (metal or ceramic) with flexible buffer portion (elastomeric material). This composite design allows the rigid portion to provide structural strength and vacuum holding capability, while the elastomeric buffer portion provides compliance to accommodate substrate deformations and maintain uniform contact pressure, thereby resolving the contradiction between structural stability and substrate flatness.
2Reliability
If vacuum pressure is increased to improve substrate holding, then the substrate can be held more securely, but substrate flatness deteriorates due to excessive deformation
Solution Approach 1:
The buffer portion's elastomeric material changes its physical state under vacuum pressure, undergoing elastic deformation to distribute the vacuum force uniformly across the substrate surface. This prevents localized stress concentration that would cause substrate deformation, while still maintaining secure holding through the cumulative effect of distributed pressure.
Solution Approach 2:
The buffer portion acts as a pre-positioned cushioning layer between the rigid chuck and the substrate. This cushioning structure is designed in advance to absorb and distribute vacuum forces, preventing excessive deformation before it occurs. The buffer portion's compliance allows it to adapt to substrate irregularities and provide uniform support under vacuum conditions.
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 deformable buffer portion enhances substrate flatness, preventing performance degradation by minimizing coating thickness variations and alignment errors, thereby improving the quality of semiconductor manufacturing processes.
Implementation Method 1
The buffer portion is made of an organic composite including a polymer and a non-Newtonian fluid
Implementation Method 2
the buffer portion is deformable under a force and can restore after removing the force
Data Source
AI summary
A method of photoresist spin coating process comprises the following steps. A substrate is placed on a chuck using vacuum force or gravitational force. A photoresist chemical is spin coated over the substrate. The chuck comprises a base portion and a buffer portion. The base portion is made of an inorganic material. The buffer portion overlaps the base portion. The buffer portion is more deformable than the base portion, and the buffer portion is made of an organic composite including a polymer and a non-Newtonian fluid.