Wafer-Level Micro Device Packaging with Desiccant and Anti-Stiction
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Solution Overview
Problem
Existing methods for packaging micro devices on semiconductor wafers lack an efficient and reliable way to provide hermetic sealing and prevent stiction issues, which can lead to operational failures due to moisture and adhesion problems.
Innovation Solution
A method involving the use of a desiccant material with absorbed anti-stiction material, where the desiccant material includes dehydrated metal halides or oxides, and an encapsulation cover is bonded to a substrate to form a chamber around the micro device, allowing for simultaneous encapsulation of multiple devices and replenishment of anti-stiction material during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hermetic sealing is provided for micro devices on semiconductor wafers, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple protective functions into a single integrated encapsulation chamber structure. The cover assembly bonds to the substrate to form a sealed environment that simultaneously provides hermetic sealing, moisture protection, and anti-stiction material reservoir integration, thereby improving reliability without proportionally increasing device complexity
Solution Approach 2:
The patent employs composite material strategies by integrating desiccant material and anti-stiction materials within the encapsulation chamber. This composite approach combines structural components (substrate, cover) with functional materials (desiccant, anti-stiction coatings) to achieve multiple protective functions in a unified structure
2Reliability
If anti-stiction material is applied to micro device surfaces, then stiction prevention is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies anti-stiction material to the micro device surfaces during the fabrication process before final encapsulation. This preliminary application ensures stiction prevention is established early, and the subsequent encapsulation with desiccant material provides long-term maintenance without requiring additional precision steps
Solution Approach 2:
The desiccant material within the encapsulation chamber serves a self-service function by continuously absorbing moisture that could compromise anti-stiction material performance. This self-maintaining system preserves stiction prevention capabilities without requiring external intervention or additional precision manufacturing steps
3Productivity
If multiple micro devices are simultaneously encapsulated, then productivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent divides the encapsulation process into modular components: substrate preparation, cover assembly with integrated desiccant material, and bonding operations. This segmentation allows multiple devices to be processed simultaneously in a standardized workflow, improving productivity while keeping individual manufacturing steps manageable and repeatable
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 effectively reduces moisture in the device environment, prevents stiction issues, and maintains the reliability of micro devices by absorbing moisture and replenishing anti-stiction material, enabling high-throughput encapsulation of multiple micro devices.
Implementation Method 1
a desiccant material in the chamber, wherein an anti-stiction material is absorbed in the desiccant material
Implementation Method 2
Moisture may be effectively removed from the environment of an encapsulated micro device
Implementation Method 3
Anti-stiction material may be replenished onto the surfaces of the encapsulated micro device during its operations to overcome stiction problems
Data Source
AI summary
An encapsulated device includes a micro device on a substrate, a cover bonded to the substrate thereby forming a chamber to encapsulate the micro device, and a desiccant material on the cover and in the chamber. An anti-stiction material is absorbed in the desiccant material.