Getter Material Self-Alignment via Blind Hole Etching
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Solution Overview
Problem
Current methods for depositing getter materials on substrates for encapsulating microelectronic devices, such as MEMS and NEMS, using stencils are costly, complex, and inefficient, leading to alignment issues and increased substrate surface area consumption, which limits integration density and form factor.
Innovation Solution
A method involving etching blind holes in the substrate and depositing a continuous layer of getter material on the substrate and hole walls, followed by selective etching to align the getter material self-aligned with the holes, eliminating the need for photolithography and stencils, and allowing precise placement to avoid electrical interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If getter material is deposited through a stencil, then localized deposit is achieved, but production cost increases and alignment precision deteriorates
Solution Approach 1:
The patent extracts the stencil from the deposition process entirely. Instead of using a stencil to define the deposit pattern, the invention uses direct geometric confinement through blind holes in the substrate. The getter material is deposited continuously over the substrate surface, and the blind holes automatically confine it to the desired locations through physical geometry rather than a removable mask.
Solution Approach 2:
The blind holes act as an intermediary structure that mediates between the continuous getter material deposit and the final localized getter configuration. The holes provide geometric confinement that directs and shapes the deposited material without requiring active control mechanisms or stencils, thereby simplifying the overall process.
2Quantity of substance
If getter material is deposited through a stencil, then localized deposit is achieved, but substrate surface area consumption increases
Solution Approach 1:
The invention applies local quality by creating distinct getter material deposits only where blind holes are present on the substrate. The continuous deposit method ensures uniform coverage, while the blind hole geometry locally confines the material to specific regions, achieving localized functionality without requiring large reserved zones for alignment margins.
3Reliability
If additional cavity is made for degassed species expansion, then outgassing is managed, but vacuum pressure deteriorates
Solution Approach 1:
The invention changes the physical state and distribution of the getter material by depositing it as a continuous layer that is then confined to blind hole regions. This parameter change in deposition geometry increases the effective surface area of the getter material within the vacuum cavity, enhancing its capacity to absorb degassed species and maintain lower pressure levels.
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 approach reduces production costs, optimizes substrate surface use, and enables precise positioning of getter material, improving vacuum maintenance and integration density without the limitations of stencil-based methods.
Implementation Method 1
Such a getter material, often metallic, is able to carry out an absorption and/or an adsorption of gas after having been thermally activated.
Implementation Method 2
Such a getter material, often metallic, is able to carry out an absorption and/or an adsorption of gas after having been thermally activated.
Implementation Method 3
depositing a layer of getter material continuously on the whole of the first face of the substrate and at least on the side walls of the blind hole
Data Source
Figure 1A~2
Figure 3~4C
Figure 5A~6
AI summary
Method for making a substrate (100) comprising at least one getter material disposed on walls of at least one blind hole (106), comprising at least the steps of: - etching the blind hole through a first face (102) of the substrate, - depositing a continuous layer of getter material (120) on the whole of the first face of the substrate and at least on lateral walls (110) of the blind hole, - etching a part of the layer of getter material on the first face of the substrate such that said first face of the substrate is no longer covered by the getter material, wherein the step of etching a part of the layer of getter material (120) comprises the implementation of an ion machining etching, or a planarization or a mechano-chemical polishing.