3D Stacked Microphone Package Using Flip Chip
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Solution Overview
Problem
Conventional microphone packages using wire bonding technology with a metal lid attachment result in larger package sizes, which can be a limitation in compact electronic devices.
Innovation Solution
The use of flip chip technology with a passive-on-glass (POG) filter design and a 3D stack of a MEMS device and an ASIC, where the ASIC serves as the package substrate, to create a smaller, thinner, and more efficient microphone package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding technology with metal lid attachment is used, then manufacturing reliability is improved, but package size increases
Solution Approach 1:
The patent transitions from planar wire bonding to three-dimensional vertical stacking, where the MEMS diel is positioned above the IC die in the Z-direction. This dimensional change eliminates the need for lateral wire bonds and metal lid attachments, reducing package footprint while maintaining electrical connectivity through vertical vias and bumps.
Solution Approach 2:
The patent integrates multiple functions into unified structures: the substrate serves as both mechanical support and electrical interconnection carrier, the IC die combines signal processing with packaging functions, and vertical vias integrate both mechanical alignment and electrical connection roles, eliminating separate wire bonds and lids.
2Ease of manufacture
If conventional wire bonding technology is used, then ease of manufacture is improved, but package thickness increases
Solution Approach 1:
The invention moves from two-dimensional planar assembly to three-dimensional vertical stacking, placing the MEMS diel above the IC die. This reduces package thickness by eliminating the need for wire bonds that extend laterally and metal lids that add vertical height, while maintaining all necessary electrical and mechanical connections through vertical pathways.
Solution Approach 2:
The patent removes unnecessary components from the conventional microphone package: wire bonds are eliminated in favor of vertical vias, and metal lid attachments are removed entirely. This extraction of non-essential elements reduces package thickness while the core functional connections are maintained through the streamlined 3D stack architecture.
3Volume of moving object
If flip chip technology with 3D stacking is used, then package size is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary alignment and bonding operations during wafer-level fabrication before final package assembly. The MEMS diel and IC die are pre-aligned and bonded in their final vertical positions, and electrical connections are established through pre-formed vias and bumps, simplifying the final assembly process despite the complex 3D architecture.
Solution Approach 2:
The substrate and IC die serve multiple functions simultaneously: mechanical support, electrical interconnection, thermal management, and structural alignment references. This multi-functionality reduces the number of separate components and assembly steps needed, offsetting the complexity introduced by the three-dimensional stacking architecture.
4Temperature
If conventional package design is used, then heat dissipation is adequate, but package weight increases
Solution Approach 1:
The patent combines thermal management with the structural packaging functions by using the substrate and IC die as integrated heat dissipation pathways. The same materials and structures that provide mechanical support and electrical connections also serve as thermal conduction paths, eliminating the need for separate heavy heat sinks or thermal management components.
Data Source
AI summary
Certain aspects of the present disclosure generally relate to a microphone package, and more particularly, to a microphone package implemented using flip chip technology. An example microphone package generally includes an integrated circuit (IC), a substrate, and a transducer disposed between the substrate and the IC, wherein the IC or the substrate comprises a perforation above or below the transducer.