Encapsulation Structure for Electromagnetic Radiation Detection
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Solution Overview
Problem
The existing methods for manufacturing devices that detect electromagnetic radiation, such as infrared or terahertz, face mechanical strength issues due to thermal expansion differences in encapsulation and sealing materials, leading to embrittlement under high temperatures.
Innovation Solution
A manufacturing method involving the production of a thin encapsulation layer and a sealing layer with a local break in continuity, achieved by creating a relief structure during the deposition of the sealing layer, which helps to relax mechanical stresses caused by thermal expansion differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If different materials with different coefficients of thermal expansion are used for encapsulation and sealing layers, then the device can be manufactured with standard materials, but mechanical stresses are generated during high-temperature exposure leading to embrittlement
Solution Approach 1:
The patent introduces a relief structure that segments the sealing layer into distinct regions: a first region directly on the encapsulation layer and a second region on the relief. This segmentation allows differential thermal expansion between materials while preventing stress propagation throughout the entire structure, thereby maintaining mechanical strength despite using standard materials with different CTE coefficients.
Solution Approach 2:
The relief structure creates local quality differences in the sealing layer, with the first region having different mechanical properties than the second region. This local differentiation allows the sealing layer to accommodate thermal expansion differences at specific locations while maintaining overall structural integrity, resolving the contradiction between ease of manufacture and mechanical strength.
2Reliability
If a continuous sealing layer is used to ensure hermeticity, then the cavity is properly sealed, but thermal expansion differences cause mechanical stresses that embrittle the structure
Solution Approach 1:
The sealing layer is segmented into a first region and a second region separated by the relief structure. This segmentation maintains hermetic sealing through the first region while the second region on the relief accommodates thermal expansion, preventing stress propagation that would otherwise embrittle the continuous structure.
Solution Approach 2:
The patent changes the physical parameters of the sealing layer by creating the relief structure, which modifies the local thickness and mechanical properties. This parameter change allows the sealing layer to maintain hermeticity while accommodating thermal expansion differences, thereby preventing embrittlement.
3Strength
If localized etching steps are used to address stress issues, then mechanical strength can be improved, but the device complexity and manufacturing steps increase
Solution Approach 1:
The relief structure is created during the deposition process itself, before final device assembly. This preliminary action incorporates the stress-relief functionality into the manufacturing process rather than requiring separate localized etching steps, thereby improving mechanical strength without increasing device complexity.
Solution Approach 2:
The patent merges the stress-relief function with the existing encapsulation structure by integrating the relief into the deposition process. This combining of functions eliminates the need for separate localized etching steps, resolving the contradiction between improving mechanical strength and reducing manufacturing complexity.
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 method enhances the mechanical strength of the encapsulation structure, maintaining performance even at high temperatures, and avoids the need for specific localized etching steps that could degrade the device's performance.
Implementation Method 1
production by physical vapor deposition of a thin so-called sealing layer covering the thin encapsulation layer
Implementation Method 2
the difference in CTE coefficients between the materials of the encapsulation and sealing layers can then generate mechanical stresses in the encapsulation structure
Implementation Method 3
having a suitable mean thickness so that, during the deposition of the thin sealing layer, the latter is formed of at least one layer portion resting on the thin encapsulation layer, and of at least one stud distinct from the layer portion and resting on the relief, thus forming a local break in the continuity of the thin sealing layer
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2E
AI summary
The invention relates to a method for manufacturing a device for detecting electromagnetic radiation, comprising an encapsulation structure (20) having an encapsulation layer (21) on which rests a relief (23), and a sealing layer (24), which has a local break in continuity at the level of the relief (23).