Molded Ceramic Surface Mount Package Hermetic Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current microelectronics packaging technologies, such as quad flat packages, face challenges in achieving hermeticity, thermal conductivity, and cost-effectiveness, particularly for high-reliability applications like MEMS devices, where plastic packages fail to meet military specifications and multi-layer ceramic methods are prohibitively expensive.
Innovation Solution
A small hermetic surface mount package is created using a ceramic base with conductive patterns, a molded dielectric layer forming a cavity, and a seal ring, which are fused together during a firing process to form a hermetically sealed package, avoiding multi-layer construction and enabling efficient thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plastic packages are used for QFPs, then manufacturing cost is reduced and ease of manufacture is improved, but hermeticity is insufficient and military leak rate specifications are not met
Solution Approach 1:
The patent employs a composite structure combining ceramic base layer with molded dielectric material (glass or ceramic-composite). This composite approach provides hermetic sealing properties of ceramic while utilizing the molding advantages of dielectric materials, achieving both reliability and ease of manufacture.
Solution Approach 2:
The package is divided into distinct functional layers: a ceramic base layer for hermetic sealing and electrical conductivity, and a molded dielectric layer for cavity formation and component protection. This segmentation allows each layer to optimize its specific function while maintaining overall hermeticity.
2Reliability
If multi-layered co-fired ceramic methods are used, then hermeticity and reliability are improved, but manufacturing complexity and start-up costs increase prohibitively
Solution Approach 1:
The manufacturing process is segmented into two main stages: first forming the ceramic base layer with required conductivity patterns, then separately molding the dielectric layer over it. This avoids the complexity of multi-layer co-firing while maintaining hermetic sealing and electrical functionality.
Solution Approach 2:
The ceramic base layer is prepared in advance with all necessary conductivity patterns and sealing structures before the dielectric molding process. This preliminary preparation simplifies the overall manufacturing by eliminating the need for complex multi-step co-firing sequences.
3Reliability
If a cavity is added to the package structure, then protection of sensitive components is improved, but manufacturing complexity increases
Solution Approach 1:
The cavity formation is merged with the dielectric molding process. The dielectric material is molded directly over the ceramic base layer to form an integrated cavity structure that simultaneously provides mechanical protection and hermetic sealing, eliminating separate cavity formation steps.
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 approach provides a cost-effective, high-reliability, and thermally efficient hermetic package that meets dimensional requirements of conventional QFPs, suitable for various microelectronic devices, including MEMS, while reducing manufacturing complexity and start-up costs.
Implementation Method 1
applying a mold over the layers to shape the dielectric during a firing process that fuses the base, preform and seal ring to create a hermetic seal
Data Source
AI summary
The surface mount package is assembled from a ceramic base which is imprinted on its upper and lower surfaces with conductive patterns for attachment of and connection to an electronic or electromechanical device, a molded dielectric layer for forming a cavity and a seal ring. The molded dielectric is formed by aligning a dielectric preform with the base, positioning the seal ring on top of the preform, then applying a mold over the layers to shape the dielectric during a firing process that fuses the base, preform and seal ring to create a hermetic seal. The preform is of sufficient thickness that the electronic device will be fully contained within the cavity when placed into the completed package.