Substrate-Free MEMS Transducer Package Design
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Solution Overview
Problem
Existing MEMS transducer packages are complex and large due to the use of substrates, making them costly and difficult to manufacture while also failing to achieve a small, thin profile for efficient performance.
Innovation Solution
A surface mountable package design that eliminates the substrate by using encapsulation material to bond the MEMS transducer and signal processing IC directly to terminal pads, with a conductive cover mechanically and electrically coupled to the terminal pads, allowing for a thin package profile and effective electromagnetic interference shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a substrate is used to mount the transducer and associated components, then the transducer is protected and components are supported, but the package becomes complex and large
Solution Approach 1:
The patent merges the substrate, cover, and transducer mounting functions into a single integrated package structure. The transducer die is directly mounted on the lead frame without requiring a separate substrate, and the cover is attached to the lead frame to form a unified housing that provides both mechanical support and EMI shielding in one component assembly.
Solution Approach 2:
The patent extracts and eliminates the substrate component from the traditional transducer package design. By removing the substrate and using the lead frame as the mounting structure, the package complexity is reduced while maintaining the necessary support and protection functions through the encapsulation material and cover assembly.
2Reliability
If a substrate and cover are used to form the transducer housing, then the transducer is protected from environmental damage, but the package height increases
Solution Approach 1:
The patent uses thin encapsulation material and a thin cover to provide environmental protection while minimizing package height. The encapsulation material forms a thin protective layer around the transducer die and lead frame, and the cover is designed as a thin structure that attaches to the lead frame, together providing environmental sealing without adding significant height.
3Object-affected harmful factors
If conductive layers are added to the substrate and cover for EMI shielding, then electromagnetic interference protection is provided, but manufacturing complexity increases
Solution Approach 1:
The lead frame serves multiple functions simultaneously: it provides mechanical support for the transducer die, acts as the mounting structure for the cover, provides electrical connections through its terminals, and offers EMI shielding through its conductive structure. This multi-functionality eliminates the need for separate EMI shielding layers and simplifies the manufacturing process.
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
The design achieves a package height of less than 0.85 mm, reducing manufacturing complexity and costs while maintaining effective acoustic performance and electromagnetic interference shielding.
Implementation Method 1
an encapsulation material bonded to at least a portion of the upper surface of the terminal pads
Implementation Method 2
the cover is electrically connected and mechanically coupled, for example by a solder joint, to a peripheral portion of the upper surface of one of the terminal pads
Data Source
AI summary
A surface mountable transducer package is provided, the design of which allows a thin package profile to be achieved. An encapsulation layer bonds to a surface of each of the terminal pads and encapsulates a portion of the transducer and at least a portion of the signal processing IC.