Elastic Membrane Stopper for CMP Substrate Holding
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Solution Overview
Problem
Existing substrate holding apparatuses for semiconductor wafers in CMP processes face challenges in uniformly applying pressure during polishing, leading to potential substrate damage and defects due to excessive inflation of the elastic membrane during substrate release, which can result in poor responsiveness and deformation of the substrate.
Innovation Solution
A substrate holding apparatus with an elastic membrane and a stopper mechanism that limits the inflation of the membrane by using a partition wall and an extending member to control the pressure chambers, preventing excessive inflation and ensuring safe substrate release by applying downward pressure and using a clearance to allow the membrane to follow the substrate during polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the elastic membrane is pressurized to release the substrate from the top ring, then the substrate can be removed from the holding apparatus, but the membrane inflates excessively causing substrate deformation and damage
Solution Approach 1:
A stopper is introduced as an intermediary component between the elastic membrane and the substrate. The stopper limits the downward movement of the membrane during pressurization, preventing excessive inflation while still allowing sufficient membrane expansion to release the substrate. This mediator component solves the contradiction by controlling the membrane's movement range.
Solution Approach 2:
The invention changes the physical state and movement parameters of the elastic membrane by introducing the stopper mechanism. The stopper constrains the membrane's downward displacement parameter, transforming the uncontrolled excessive inflation into a controlled parameter change that allows substrate release without damage.
2Ease of operation
If the elastic membrane is allowed to inflate freely during substrate release, then the substrate can be released easily, but the membrane causes excessive stress and deformation on the substrate
Solution Approach 1:
The stopper acts as a protective intermediary that mediates between the elastic membrane's inflation tendency and the substrate's vulnerability to deformation. It allows controlled membrane expansion for substrate release while blocking excessive inflation that would harm the substrate.
Solution Approach 2:
The stopper provides beforehand cushioning by being pre-positioned to limit the membrane's downward movement. This preventive measure stops excessive membrane inflation before it can cause substrate deformation, cushioning the substrate against harmful stresses during the release process.
3Object-affected harmful factors
If the membrane is constrained to prevent excessive inflation, then substrate damage is reduced, but the membrane cannot follow the substrate surface during polishing
Solution Approach 1:
The invention segments the membrane's movement into two distinct phases: during polishing, the membrane is free to expand and contract to follow the substrate surface; during release, the stopper engages to limit downward movement. This segmentation allows the membrane to be compliant when needed while preventing damage during release.
Solution Approach 2:
The system dynamically adjusts the membrane's freedom of movement based on the operational phase. During polishing, the membrane is dynamic and adaptable to substrate surface changes. During release, the stopper constrains the membrane to a controlled range of motion, providing adaptability in the release process while preventing excessive inflation.
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
This solution effectively reduces stress on the substrate, prevents damage, and ensures safe removal by limiting membrane inflation, thereby improving the responsiveness and reliability of the substrate handling process.
Implementation Method 1
a holding surface formed by an elastic membrane 4, and a plurality of pressure chambers 5, 6, 7, 8 to which a pressurized fluid is supplied are formed at a rear side of the elastic membrane 4
Implementation Method 2
a fluid pressure such as air pressure is applied to the pressure chambers 5, 6, 7, 8 to uniform the pressing force applied to the substrate
Implementation Method 3
a stopper configured to limit the inflation of the elastic membrane by being brought into contact with a part of the partition wall of the elastic membrane or an extending member extending from a rear surface of the elastic membrane
Data Source
AI summary
A substrate holding apparatus is used for holding a substrate such as a semiconductor wafer in a polishing apparatus for polishing and planarizing the substrate. The substrate holding apparatus includes an elastic membrane, a top ring body for holding the elastic membrane, and a plurality of pressure chambers partitioned by at least one partition wall of the elastic membrane. The substrate is held by a lower surface of the elastic membrane and pressed against the polishing surface with a fluid pressure by supplying a pressurized fluid to the pressure chambers. The substrate holding apparatus further include a stopper configured to limit the inflation of the elastic membrane by being brought into contact with a part of the partition wall of the elastic membrane or an extending member extending from a rear surface of the elastic membrane whose surface serves as a substrate holding surface.