Composite Package Substrate Isolates MEMS Die from External Stress
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Solution Overview
Problem
Current packaging techniques for stress-sensitive components, such as MEMS devices, face challenges in minimizing external stresses and ensuring accurate calibration due to low stiffness and susceptibility to external loads, leading to potential failure and calibration errors.
Innovation Solution
The use of a composite package substrate with a molded leadframe, where a metal leadframe is embedded in a molding material, including an insulating material like plastic or ceramic, to create a cavity package that isolates the device die from external stresses, and allows for adjustable stiffness and resonant frequency by varying the thickness of the insulating material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional package substrate is used, then the package can be manufactured with standard processes, but the substrate has low stiffness and is susceptible to external loads causing calibration errors
Solution Approach 1:
The patent applies composite materials by combining a metal leadframe with a molding material to create a package substrate with enhanced stiffness. The metal leadframe provides structural rigidity while the molding material provides insulation and protection, resolving the contradiction between needing high stiffness and maintaining manufacturability through standard composite packaging processes.
2Reliability
If the substrate stiffness is increased to reduce external stress transmission, then component reliability improves, but the resonant frequency becomes difficult to control
Solution Approach 1:
The patent applies parameter changes by varying the thickness of the insulating material layer in the composite substrate to independently control the resonant frequency of the package. This allows the substrate stiffness to be optimized for reliability while the insulating layer thickness is adjusted to achieve the desired resonant frequency characteristics.
3Ease of manufacture
If a simple substrate structure is used, then manufacturing is easier, but external stresses are transmitted to the device die causing potential failure
Solution Approach 1:
The patent uses composite materials to create a substrate that combines the stress-resistant properties of metal with the protective properties of molding material. This composite structure effectively isolates the device die from external stresses while maintaining compatibility with standard manufacturing processes for assembling the complete package.
Data Source
AI summary
An integrated device package is disclosed. The package can include a package substrate comprising a composite die pad having an upper surface and a lower surface spaced from the upper surface along a vertical direction. The composite die pad can include an insulator die pad and a metal die pad. The insulator die pad and the metal die pad can be disposed adjacent one another along the vertical direction. The substrate can include a plurality of leads disposed about at least a portion of a perimeter of the composite die pad. An integrated device die can be mounted on the upper surface of the composite die pad.