Getter Material Protection in Thermal Detector Fabrication
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Solution Overview
Problem
Existing methods for producing electromagnetic radiation detection devices with thermal detectors face challenges in achieving improved detection sensitivity and effective encapsulation, particularly in using mineral sacrificial layers and getter materials within hermetic cavities.
Innovation Solution
A method involving the deposition of a metallic getter layer, a carbonaceous sacrificial layer, and a mineral sacrificial layer, followed by selective chemical etching to form a hermetic cavity around the thermal detector, with a getter material for gas pumping and improved vacuum maintenance, and a thin encapsulation layer for enhanced sensitivity and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mineral sacrificial layer is used during production, then the thermal detector can be formed with proper structural support, but the getter material located on the substrate surface is damaged or removed during the chemical etching process
Solution Approach 1:
A protective sacrificial layer is introduced as an intermediary between the mineral sacrificial layer and the getter material. This protective layer is selectively removed after the getter material is deposited, allowing the mineral sacrificial layer to be removed without damaging the getter material. The protective layer acts as a temporary shield that enables sequential removal of different sacrificial materials.
Solution Approach 2:
The sacrificial layer structure is segmented into multiple functional layers: a protective sacrificial layer that shields the getter material, and a mineral sacrificial layer that provides structural support during fabrication. Each layer can be selectively removed based on its specific properties and timing requirements in the manufacturing process.
2Reliability
If the getter material is deposited on the substrate surface early in the process, then vacuum maintenance is improved, but the getter material is damaged during subsequent chemical etching of mineral sacrificial layers
Solution Approach 1:
The protective sacrificial layer is deposited beforehand to cover and protect the getter material before any chemical etching processes occur. This preliminary protective action ensures that the getter material remains intact throughout the fabrication process, allowing vacuum maintenance capabilities to be fully realized without compromising the getter material.
3Ease of manufacture
If chemical etching is used to remove mineral sacrificial layers, then the hermetic cavity is successfully formed, but the getter material is simultaneously removed or damaged
Solution Approach 1:
The protective sacrificial layer is selectively extracted or removed after serving its protective function. This removal exposes the getter material for proper hermetic sealing while having protected it during the chemical etching process that removes the mineral sacrificial layer and forms the hermetic cavity.
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 enhances the detection sensitivity of the thermal detectors and improves the structural integrity and service life of the detection device by maintaining a vacuum within the hermetic cavity and ensuring effective encapsulation of the thermal detectors.
Implementation Method 1
a layer of getter material being located in the hermetic cavity
Implementation Method 2
selective chemical etching to form a hermetic cavity
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D~2F
AI summary
The invention relates to a method for making an electromagnetic radiation detection device (1) comprising at least one thermal detector (10) with an absorbing membrane (11) suspended above a substrate (2), intended to be located in a hermetically sealed cavity (3), comprising the following steps: - deposition, on the substrate (2), of a metallic layer called a getter (40) comprising a metallic material with a getter effect; - deposition of a sacrificial layer called a carbon layer (50) of amorphous carbon on the metallic getter layer (40); - deposition of at least one mineral sacrificial layer (60A, 60B) on the carbon sacrificial layer (50); - mechano-chemical flattening of the mineral sacrificial layer (60A); - fabrication of the thermal detector (10) such that the absorbing membrane (11) is made on the mineral sacrificial layer (60A); - removal of the mineral sacrificial layer (60A, 60B); - removal of the sacrificial carbon layer (50).