Etched Substrate Holder with Stop Layer for Microelectronics
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Solution Overview
Problem
Existing substrate supports for microelectronics face issues with rigidity, temperature resistance, particulate contamination, roughness, flatness, and reproducibility, particularly when accommodating substrates of smaller diameters in machines designed for larger ones, leading to deformation, breakage, and incompatibility with clean room standards.
Innovation Solution
A method involving a stack of two substrates secured by etching with a stop material to produce a support with controlled depth and positioning, ensuring good rigidity, temperature resistance, and surface quality, using direct bonding or anodic bonding for enhanced thermal stability and allowing for vertical positioning without additional holding elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a location is hollowed out in a substrate to accommodate a smaller substrate, then the substrate support can be used in machines designed for larger substrates, but the remaining thickness of the substrate at the location becomes thin, causing mechanical weakness and potential breakage
Solution Approach 1:
The support is divided into multiple layers: a first substrate containing the location, a second substrate providing structural reinforcement, and an etching stop layer separating them. This segmentation allows the first substrate to be thin enough for precise etching while the second substrate provides the necessary mechanical strength.
Solution Approach 2:
The support uses a composite structure combining a first substrate (e.g., silicon) with a second substrate (e.g., glass or ceramic) that have different mechanical properties. The etching stop layer (e.g., oxide) bonds these materials, creating a composite structure that achieves both adaptability and strength.
2Adaptability or versatility
If a location is etched in a substrate to receive a smaller substrate, then the support can accommodate different substrate sizes, but the roughness and flatness of the location walls become difficult to control
Solution Approach 1:
The etching stop layer acts as an intermediary between the first substrate and the second substrate. It provides a controlled, flat surface for the location etching process while protecting the second substrate from etching, thereby ensuring precise roughness and flatness control.
Solution Approach 2:
The etching stop layer is deposited on the first substrate before the location etching process. This preliminary action creates a protected surface that ensures precise etching depth and wall quality, preventing over-etching and maintaining manufacturing precision.
3Ease of manufacture
If mechanical thinning is used to create a location, then the substrate can be thinned, but a work-hardened zone forms on the surface, generating particles that contaminate the clean room environment
Solution Approach 1:
The harmful work-hardened zone and particle generation are extracted from the process by replacing mechanical thinning with chemical etching. The etching process removes material without creating a work-hardened zone, thereby eliminating the source of particulate contamination.
Solution Approach 2:
The mechanical thinning process is replaced with a chemical etching process using the etching stop layer as a mask. This substitution eliminates mechanical contact that causes work hardening and particle generation, ensuring clean room compatibility.
4Ease of manufacture
If bonding is used to attach material portions to block the substrate, then the support structure can be formed, but the positioning reproducibility and temperature resistance of the glue are compromised
Solution Approach 1:
The etching stop layer is designed as a sacrificial layer that is etched away during the location formation process. This disposable layer simplifies the bonding process and eliminates the need for temperature-resistant adhesives, as the bonding is achieved through the etching process itself rather than through glue.
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 provides a substrate support with improved mechanical stability, high temperature resistance, reduced particulate contamination, and precise control over surface roughness and flatness, enabling safe handling and processing of smaller substrates in larger machines without compromising cleanliness or accessibility.
Implementation Method 1
etching, through the first of the two substrates and with a stop on the etching stop material, of at least one location suitable to receive the substrate intended to be supported by the support
Implementation Method 2
the two substrates being secured to one another such that one of the main faces of a first of the two substrates is arranged in facing one of the main faces of the second of the two substrates
Data Source
Figure 1~4
Figure 5A~5B
Figure 6A~6B
AI summary
The invention relates to a method for building a holder (100) for at least one substrate, comprising at least the implementation of the following steps: building a stack (118) comprising at least two substrates (102, 104), each of the two substrates including two opposite main surfaces (114), the two substrates being rigidly attached to one another such that one of the main surfaces of a first of the two substrates is arranged facing one of the main surfaces of the second of the two substrates and against an etch resist material (120), etching, through the first of the two substrates and stopping at the etch resist material, at least one location (122) capable of accommodating a substrate intended to be supported by the holder.