Segmented Substrate Holder Vacuum Release Mechanism
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Solution Overview
Problem
Conventional substrate holders face difficulties in releasing thin, brittle semiconductor wafers without applying stress, due to the formation of a single fluid path that weakens the separation force from the suction pad, especially when using foam materials.
Innovation Solution
A substrate holder with a suction surface featuring multiple closed sections surrounded by convexities, independent fluid communication passages, and flow-rate regulators, allowing for controlled fluid supply to each section to facilitate reliable separation of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single vacuum production hole is used to hold the substrate, then the substrate can be held by vacuum suction, but it becomes difficult to release the substrate from the suction pad without forming a single fluid path that weakens separation force
Solution Approach 1:
The suction pad is divided into multiple independent suction regions (first, second, third, and fourth suction regions) separated by partition walls. Each region has its own vacuum production holes and can be independently evacuated or pressurized. This segmentation allows selective release of the substrate from different regions, improving release effectiveness while maintaining reliable holding capability.
Solution Approach 2:
Different regions of the suction pad have different functional characteristics. The first and second suction regions are used for primary substrate holding, while the third and fourth suction regions can be selectively pressurized to facilitate release. The partition walls create local structural differences that enable targeted fluid supply to specific regions for controlled release.
2Reliability
If foam material is used for the suction pad, then the substrate can be held effectively, but the foam acts as microscopic suction cups that make it difficult to release the substrate
Solution Approach 1:
The foam suction pad is segmented into multiple independent regions by partition walls. This segmentation prevents the formation of a continuous microscopic suction cup effect across the entire pad. When fluid is supplied to specific regions, the segmented structure allows localized pressure equalization and release without the entire foam structure acting as a unified suction barrier.
Solution Approach 2:
Partition walls act as intermediaries between different suction regions. These walls prevent direct fluid communication between regions and block the propagation of the microscopic suction cup effect across the foam material. The partition walls enable selective pressurization of specific regions to overcome the foam's suction holding effect in a controlled manner.
3Ease of operation
If fluid is supplied to release the substrate, then the substrate can be separated from the fluid path, but most fluid is discharged to the exterior through the fluid path reducing separation force
Solution Approach 1:
The fluid supply system is segmented into multiple independent channels, each serving specific suction regions. This segmentation allows fluid to be directed precisely to regions where release is needed, preventing fluid discharge through unused fluid paths and improving supply efficiency.
Solution Approach 2:
Before substrate release, the system preliminarily supplies fluid to specific suction regions through the segmented fluid paths. This preliminary action prepares the targeted regions for release by equalizing pressure in advance, ensuring effective separation while minimizing fluid loss through other paths.
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
Enables the substrate to be released from the suction surface without stress by maintaining pressure in isolated sections, ensuring reliable separation and reducing the external force required during release.
Implementation Method 1
A substrate holder which holds a surface of a substrate by vacuum suction is typically used as a device for holding a thin plate-like substrate
Implementation Method 2
a fluid supply source selectively supplyable to the plurality of closed sections through the communication passages, respectively and independently
Data Source
AI summary
A substrate holder is a mechanism for holding a substrate, to be polished, by vacuum suction. The substrate holder includes a substrate-holding stage having a suction surface for the substrate, and a fluid passage selectively coupled to a vacuum source and a fluid supply source. The suction surface has a plurality of closed sections surrounded by convexities, and the fluid passage includes a plurality of communication passages which are in fluid communication with the plurality of closed segments respectively and independently.