Mineral Sacrificial Layer Encapsulation for Thermal Detector Strength
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Solution Overview
Problem
Existing methods for manufacturing electromagnetic radiation detection devices, particularly those using thermal detectors in hermetic cavities, face challenges in achieving sufficient mechanical strength of the encapsulation structure, leading to risks of separation at the cavity edges.
Innovation Solution
A method involving the production of thermal detectors using mineral sacrificial layers, followed by deposition of a thin encapsulation layer and creation of vents for partial removal by wet chemical etching, resulting in a peripheral wall with lateral shrinkage and the introduction of reinforcing pillars to enhance mechanical strength, specifically in the intermediate zone surrounding the thermal detector matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thin encapsulation layer is used to reduce the size of the reading substrate, then the device complexity is reduced, but the mechanical strength of the encapsulation structure deteriorates
Solution Approach 1:
The encapsulation structure is segmented into multiple functional components: a thin encapsulation layer for electrical insulation and a separate peripheral wall structure for mechanical support. This segmentation allows each component to be optimized independently - the thin layer reduces substrate size while the peripheral wall provides the necessary mechanical strength.
Solution Approach 2:
The encapsulation structure uses composite construction combining different materials with complementary properties. The thin encapsulation layer provides electrical insulation and hermetic sealing, while the peripheral wall made of sacrificial layer material provides mechanical reinforcement. This composite approach resolves the contradiction between thin structure and mechanical strength.
2Strength
If the encapsulation structure is made stronger to prevent detachment, then the mechanical strength improves, but the manufacturing complexity increases
Solution Approach 1:
The peripheral wall structure is formed during the manufacturing process by leaving portions of the sacrificial layer unetched, rather than adding it as a separate step. This preliminary action integrates the reinforcement structure into the standard manufacturing flow, avoiding increased manufacturing complexity.
Solution Approach 2:
The sacrificial layer serves as an intermediary material that performs multiple functions: it provides mechanical support during manufacturing, defines the peripheral wall structure through selective etching, and enables the formation of the reinforced encapsulation structure. This intermediary approach simplifies the overall manufacturing process.
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 approach improves the mechanical strength of the encapsulation structure, reducing the risk of separation and enhancing the device's ability to withstand pressure differences between the cavity and external environments.
Implementation Method 1
partial removal of the mineral sacrificial layers, by wet chemical etching in an acid medium, through the vents
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D~2F
AI summary
The invention relates to a method for manufacturing a detection device (1) comprising the following steps: the creation of thermal detectors (20) and an encapsulation structure (30) using sacrificial mineral layers (61, 62); the partial elimination of the sacrificial mineral layers (61, 62) using wet chemical acid etching, so as to uncover the thermal detectors (20) and obtain a peripheral wall (32) and so as to uncover an upper portion (31.1) of the encapsulation thin layer (31); • the peripheral wall (32) then exhibiting a lateral recess manifesting itself as a vertical enlargement of the cavity (2), between the reading substrate (10) and the upper portion (31.1), this lateral recess defining an intermediate zone (Zr); the creation of reinforcing pillars (31.2) arranged in the intermediate zone (Zr) around the array of thermal detectors (20).