Composite MEMS Microphone Carrier for Thin Packages and Larger Back Volume
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Solution Overview
Problem
Conventional integrated device packages face a dilemma between reducing size and maintaining performance, particularly for microelectronic mechanical systems (MEMS) devices like piezoelectric MEMS microphones, as thinner packages compromise back volume and durability.
Innovation Solution
The integrated device package incorporates a carrier with a partially extending opening and a multilayer structure, including a high-resistive material layer, to enhance back volume and durability while maintaining reduced thickness, using a ceramic or glass layer to match thermal expansion and improve electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the package thickness is reduced to achieve a thin profile, then the package size is minimized and fits small form-factor devices, but the back volume available for MEMS device operation is reduced
Solution Approach 1:
The patent introduces a recess in the carrier substrate that extends downward from the top surface, creating a vertical dimension for the back volume. This allows the back volume to be accommodated within the package thickness by utilizing the recess space, rather than requiring additional horizontal or vertical expansion of the overall package.
Solution Approach 2:
The MEMS device is positioned within the recess of the carrier substrate, nesting the device and its required back volume inside the carrier structure itself. This nesting approach allows the back volume to be contained within the package footprint without increasing the overall package thickness.
2Reliability
If the back volume is increased to improve MEMS device performance, then the sensitivity and operation of MEMS devices is enhanced, but the package thickness increases
Solution Approach 1:
The recess creates a downward vertical space within the carrier substrate thickness, allowing the back volume to be formed in a direction perpendicular to the main package thickness dimension. This enables sufficient back volume for MEMS performance without increasing the overall package thickness profile.
Solution Approach 2:
The carrier substrate has different local properties: the recess area provides the necessary back volume for MEMS performance, while the rest of the substrate maintains structural integrity and electrical connectivity. This local differentiation allows performance optimization without compromising overall package dimensions.
3Reliability
If a multilayer carrier structure with high resistive material is used to improve durability and thermal matching, then the package reliability is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The carrier substrate uses a composite multilayer structure combining a first substrate material with a second high resistive material layer. This composite structure provides both mechanical durability and thermal expansion matching with the MEMS device, while the layer configuration can be integrated into standard PCB manufacturing processes.
Solution Approach 2:
The second layer material is selected with specific parameter properties (high electrical resistance and matched coefficient of thermal expansion) to improve reliability. These parameter changes are achieved through material selection rather than complex structural design, maintaining manufacturing feasibility.
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 design improves MEMS device performance by increasing back volume without increasing thickness, enhancing sensitivity and durability, and reducing current leakage.
Implementation Method 1
The electronic component can be a microelectronicmechanical systems die. The microelectronicmechanical systems die can be a piezo electric microelectronicmechanical systems microphone.
Implementation Method 2
The opening can include an acoustic cavity. The cavity can be filled with an inert gas.
Data Source
AI summary
An integrated device package is disclosed. The integrated device package can include a carrier that has a multilayer structure having a first layer and a second layer. The first layer at least partially defines a lower side of the carrier. An electrical resistance of the second layer is greater than an electrical resistance of the first layer. The integrated device package can include a microelectronicmechanical systems die that is mounted on an upper side of the carrier opposite the lower side. The integrated device package can include a lid that is coupled to the carrier. The lid and the microelectronicmechanical systems die are spaced by a gap defining a back volume.