Packaged MEMS Microphone With Lead Frame Intermediary
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Solution Overview
Problem
The interconnection of MEMS microphones with other components is challenging and costly due to the need for expensive specialized equipment, particularly in flip chip interconnections, which increases fabrication costs.
Innovation Solution
A packaged microphone design featuring a lid structure with a concavity for mounting the microphone die, a substrate for electrical connection, and a seal to create acoustic and electrical isolation, allowing for easy electrical interconnection and batch processing, reducing the need for expensive equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flip chip interconnections are used to connect the microphone with other components, then electrical connection reliability is improved, but fabrication cost increases due to expensive specialized equipment
Solution Approach 1:
The patent introduces a lead frame as an intermediary component between the microphone die and the substrate. The lead frame provides standardized electrical connection interfaces that can be connected to the substrate using conventional wire bonding or ball grid array techniques, eliminating the need for expensive flip chip equipment while maintaining reliable electrical connections. The lead frame acts as a mediator that translates the microphone's connection requirements into compatible interfaces with the substrate.
Solution Approach 2:
The patent employs a disposable lead frame structure that is inexpensive and can be easily manufactured using standard PCB fabrication processes. This lead frame is designed to be a single-use component that facilitates the connection process without requiring expensive equipment, thereby reducing fabrication costs while maintaining adequate connection reliability for the application.
2Ease of manufacture
If conventional packaging methods are used, then manufacturing simplicity is maintained, but batch processing capability and fabrication efficiency are reduced
Solution Approach 1:
The patent divides the packaging structure into modular segments: a substrate, a lead frame, and a microphone die. This segmentation allows each component to be manufactured separately using optimized processes, then assembled together. The lead frame can be produced in batches using standard PCB fabrication, and multiple microphone dies can be mounted on individual lead frames simultaneously, enabling batch processing while maintaining manufacturing simplicity.
Solution Approach 2:
The lead frame serves multiple functions simultaneously: it provides electrical connections, mechanical support for the microphone die, acoustic sealing surfaces, and alignment references. This multi-functionality reduces the number of separate components needed, simplifying the overall manufacturing process while enabling efficient batch processing through standardized production techniques.
3Device complexity
If the microphone die is directly mounted on the substrate, then electrical connection is simplified, but acoustic sealing and protection from environment are compromised
Solution Approach 1:
The lead frame serves as an intermediary structure between the microphone die and the substrate. It provides dedicated electrical connection points that simplify wiring while simultaneously providing surfaces for acoustic sealing. The lead frame's design allows the microphone die to be mounted with proper acoustic sealing surfaces that maintain environmental protection, while electrical connections are made through standardized interfaces on the lead frame rather than direct substrate contact.
Solution Approach 2:
The patent merges the electrical connection function and acoustic sealing function into a single lead frame component. The lead frame integrates both electrical contact pads and acoustic sealing surfaces, allowing simultaneous achievement of simplified electrical connections and reliable acoustic sealing without requiring separate components for each function.
Data Source
AI summary
A packaged microphone has a lid structure with an inner surface having a concavity, and a microphone die secured within the concavity. The packaged microphone also has a substrate coupled with the lid structure to form a package having an interior volume containing the microphone die. The substrate is electrically connected with the microphone die. In addition, the packaged microphone also has aperture formed through the package, and a seal proximate to the microphone die. The seal acoustically seals the microphone and the aperture to form a front volume and a back volume within the interior volume. The aperture is in acoustic communication with the front volume.