MEMS Package Guard Rings Prevent Eutectic Bonding Shorts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the fabrication of micro electro mechanical system (MEMS) devices, eutectic bonding between substrates can lead to electrical shorts due to laterally stretching metallic materials contacting neighboring bonding material, which compromises the integrity and functionality of the package system.
Innovation Solution
The use of strategically formed openings and guard rings in the substrates to accommodate and manage the softened metallic bonding material during eutectic bonding, preventing electrical shorts by ensuring the metallic material fills specific openings and interacts with guard rings, thus maintaining electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If eutectic bonding is performed with metallic material, then electrical coupling between substrates is achieved, but lateral stretching of metallic material causes electrical shorts to neighboring bonding material
Solution Approach 1:
The substrate surface is segmented into distinct regions: bonding regions where metallic material is applied for electrical coupling, and non-bonding regions that remain free of metallic material. This spatial segmentation prevents lateral stretching of metallic material from one bonding region from contacting neighboring bonding regions, thereby eliminating electrical shorts while maintaining effective electrical coupling at designated locations.
Solution Approach 2:
Different regions of the substrate surface are given different properties: bonding regions are prepared to receive and bond metallic material for electrical coupling, while non-bonding regions are kept free of metallic material to prevent electrical shorts. This local differentiation ensures that metallic material only forms electrical connections where intended, preventing harmful lateral spreading to adjacent areas.
2Reliability
If openings are formed in substrates to accommodate metallic material, then electrical isolation is improved, but manufacturing complexity increases
Solution Approach 1:
Openings are pre-formed in the substrate surfaces at designated bonding locations before the eutectic bonding process. These openings are strategically positioned to accommodate the metallic material and define the bonding regions. By preparing these openings in advance, the substrate structure guides the metallic material into correct positions, ensuring electrical isolation between adjacent bonding regions while simplifying the overall manufacturing process through pre-planned structural features.
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 reliability and hermeticity of the package system by preventing electrical shorts and ensuring proper bonding, thereby improving the performance and durability of MEMS devices.
Implementation Method 1
eutectic bonding between substrates can lead to electrical shorts due to laterally stretching metallic materials contacting neighboring bonding material
Implementation Method 2
the Al pad is subjected to a thermal treatment and a pressure, such that the Al pad is softened and melted
Data Source
AI summary
A package system includes a first substrate; and a second substrate electrically coupled with the first substrate. The package system further includes a semiconductor material between the first substrate and the second substrate. The semiconductor material includes a pad, and at least one guard ring surrounding the pad and spaced from the pad. The package system further includes a metallic material bonded to the semiconductor material, wherein the metallic material at least partially fills at least one opening in at least one of the first substrate or the second substrate.