Microelectronic Encapsulation Using Lateral Protective Zones
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Solution Overview
Problem
Existing encapsulation methods for air-sensitive microelectronic devices, such as lithium microbatteries, face challenges in miniaturization and handling due to the need for temporary bonding and separation steps, which increase manufacturing costs and complexity, especially when dealing with thin or ultrathin substrates that require protection from oxygen and water vapor.
Innovation Solution
A process involving a support substrate with a bonding layer and an encapsulation cover, where a lateral protective layer is applied to create a protected zone, allowing for chemical etching to thin the substrate and cover outside this zone, eliminating the need for temporary joining and unjoining steps and enabling easy handling of miniaturized devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If temporary bonding and separation steps are used to handle thin substrates, then ease of handling is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies preliminary action by depositing the protective layer on the lateral faces of the support substrate before the thinning process. This pre-protection enables the substrate to be thinned to ultrathin dimensions while maintaining handling capability through the preserved lateral faces, eliminating the need for temporary bonding and separation steps.
2Volume of moving object
If substrates are thinned to meet miniaturization criteria, then device size is reduced, but ease of handling deteriorates due to increased fragility
Solution Approach 1:
The patent applies local quality by selectively protecting only the lateral faces of the support substrate with a protective layer, while the main encapsulation faces are thinned to ultrathin dimensions. This localized protection strategy enables the substrate to be ultrathin for miniaturization while maintaining handling capability through the protected lateral faces that serve as grip zones.
3Length of stationary object
If chemical or mechanical thinning is applied to rigid substrates, then substrate thickness is reduced, but ease of handling worsens due to increased fragility
Solution Approach 1:
The patent applies preliminary action by depositing the protective layer on the lateral faces before the thinning process. This pre-protection enables the substrate to be thinned to ultrathin dimensions while maintaining handling capability through the preserved lateral faces, eliminating the need for temporary bonding and separation steps.
4Reliability
If bonding layers and separation steps are implemented, then encapsulation reliability is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent applies preliminary action by depositing the protective layer on the lateral faces before the thinning process. This pre-protection enables the substrate to be thinned to ultrathin dimensions while maintaining handling capability through the preserved lateral faces, eliminating the need for temporary bonding and separation steps.
Solution Approach 2:
The patent extracts the handling function from the substrate material itself by preserving the lateral faces with protective layers, rather than adding separate temporary bonding layers. The lateral faces serve as inherent grip zones that enable handling of ultrathin substrates without additional components.
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 effectively encapsulates microelectronic devices with thin or ultrathin substrates and covers, providing protection from air and oxidants while simplifying the manufacturing process by reducing steps and costs, and allowing for easy handling and separation of miniaturized devices.
Implementation Method 1
depositing a bonding layer, in a second material, on the first face of the substrate
Implementation Method 2
depositing a lateral protective layer of a fourth material on the lateral face of the support substrate, on the lateral face of the encapsulation cover
Implementation Method 3
thinning of the second main face of the support substrate and/or of the second main face of the encapsulation cover outside the protected zone, by etching chemical
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
A method for encapsulating a microelectronic device (300) comprising the following successive steps: a) providing a support substrate (200), comprising a first main face on which a microelectronic device (300) is disposed, a second main face, and a lateral face, b) depositing an adhesive layer (500) on the first face of the substrate (200), c) positioning an encapsulation cover (400) comprising a first main face, a second main face, and a lateral face, on the adhesive layer (500), d) depositing a lateral protective layer (600) on: - the lateral face and the periphery of the second face of the support substrate (200), - the lateral face and the periphery of the second face of the encapsulation cover (400), - the lateral protective layer (600) delimiting a protected area,e) thinning of the second main face of the support substrate (200) and/or of the second main face of the encapsulation cap (400) outside the protected area.