Vacuum Chuck Carrier Element for Bowed Substrate Fixation
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Solution Overview
Problem
Existing substrate holding systems, particularly those using vacuum suction, face challenges in securely fixing bowed substrates due to inadequate vacuum establishment and subsequent issues like substrate slippage, vibrations, and maintenance requirements related to sealing lips.
Innovation Solution
A holding apparatus with a vertically movable carrier element and a lifting mechanism that creates a sealed cavity for negative pressure application, allowing for secure fixation and guidance of bowed substrates by initially using a smaller vacuum surface, which then gets clamped firmly against a larger surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum suction is used to fix substrates on spinner chucks, then flat substrates can be held securely, but bowed substrates cannot be fixed properly due to insufficient vacuum establishment
Solution Approach 1:
The holding apparatus is divided into two functional zones: a central carrier element with a small support surface for initial vacuum fixation, and an outer main body with a large clamping surface for final secure holding. This segmentation allows the system to first establish vacuum on a small area where bowed substrates can be reliably captured, then expand the holding area to accommodate the full substrate while maintaining fixation reliability.
Solution Approach 2:
The carrier element protrudes from the main body to create a preliminary fixation zone before the substrate is fully engaged with the clamping surface. This preliminary action allows vacuum to be established on a small, accessible area first, securing the bowed substrate in position before the full clamping surface is engaged, thereby enabling subsequent reliable fixation of the entire substrate.
2Reliability
If soft sealing lips are arranged on the support surface to improve fixation of bowed substrates, then vacuum can be established, but the substrate is not guided horizontally and may slide or float during suction
Solution Approach 1:
The carrier element is designed with its support surface substantially flush with the clamping surface of the main body when retracted. This equipotential arrangement creates a smooth transition zone that guides the substrate horizontally during engagement, preventing lateral sliding or floating while maintaining vacuum sealing effectiveness throughout the substrate surface.
3Reliability
If sealing lips are used to hold bowed substrates, then vacuum suction can be established, but maintenance outlay increases due to soiling, ageing, and particle generation
Solution Approach 1:
The problematic soft sealing lips are extracted from the support surface and replaced with a hard, seal-free carrier element design. The carrier element creates a sealed cavity through its geometry and engagement with the main body, eliminating the need for compliant sealing materials that degrade over time. This extraction of the sealing function from the support surface resolves the maintenance issue while preserving vacuum capability.
Solution Approach 2:
The invention replaces expensive, short-lived soft sealing lips with a durable, long-lasting hard carrier element. The hard material does not degrade, generate particles, or require frequent replacement, thereby eliminating the maintenance outlay associated with soft sealing lips while maintaining the necessary vacuum sealing function through geometric sealing.
4Reliability
If a large vacuum surface is used to hold substrates, then secure fixation is achieved, but bowed substrates cannot be initially captured due to insufficient vacuum pressure distribution
Solution Approach 1:
The vacuum holding function is segmented into two stages: initial capture on the small carrier element surface where vacuum pressure is concentrated and effective, and subsequent expansion to the large main body clamping surface where distributed pressure provides secure holding. This segmentation resolves the contradiction by applying high vacuum pressure on a small area first, then distributing the load over a large area for secure fixation.
Solution Approach 2:
The small carrier element surface acts as a preliminary vacuum application zone that captures the bowed substrate before the full vacuum system is engaged. This preliminary action establishes initial vacuum pressure concentration on a small area, securing the substrate in position, after which the full large-vacuum-surface system is activated for secure holding with distributed pressure.
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 ensures secure and efficient holding of bowed substrates, reducing vibrations and maintenance needs by providing a stable vacuum seal and uniform force distribution, enabling effective processing and rotation for further operations.
Implementation Method 1
a lifting element (115a-b) which lifts the carrier element (107) to the loading position
Implementation Method 2
a sealed cavity (113) is provided between the main body (103) and the carrier element (107), which cavity can have a negative pressure applied thereto which counteracts the effect of the lifting element (115a-b)
Implementation Method 3
The substrates are fixed on the chuck, e.g. by means of vacuum suction
Data Source
AI summary
A holding apparatus, in particular a chuck, for a substrate comprises a main body with a upper side, a carrier element arranged in a recess of the main body so as to be vertically movable such that it can be adjusted between a protruding loading position and a retracted clamping position, the carrier element comprising a support surface for placement of the substrate. The support surface has a smaller diameter than the main body. A lifting element lifts the carrier element to the loading position. The carrier element seals the recess such that a sealed cavity is provided between the main body and the carrier element, which cavity can have a negative pressure applied thereto which counteracts the effect of the lifting element.