RF Package Lid Structure for Thermal Dissipation and Hermeticity
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Solution Overview
Problem
Existing RF packages face challenges in achieving adequate thermal dissipation and hermeticity, which are crucial for maintaining signal integrity, reducing noise, and preventing moisture and contamination, especially in high-power applications where heat flux is concentrated.
Innovation Solution
The packaging device incorporates a package lid and base made of materials with high thermal conductivity, such as silicon carbide or copper, and uses thermal interface layers of sintered gold, silver, or copper to enhance heat dissipation, along with a metal shielding layer to achieve near-hermetic levels, allowing top-side cooling and improved hermeticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional packaging materials are used, then manufacturing cost is reduced, but thermal dissipation performance deteriorates
Solution Approach 1:
The patent employs composite material structures combining copper (high thermal conductivity) with stainless steel (mechanical strength and corrosion resistance) in the package lid and base. This composite approach achieves superior thermal dissipation performance while managing manufacturing complexity through established metallurgical joining techniques.
Solution Approach 2:
The invention changes the thermal conductivity parameter of packaging materials from conventional low-conductivity materials to high-conductivity materials (copper with thermal conductivity ≥400 W/(m·K)). This parameter change directly addresses thermal dissipation requirements while the patent provides fabrication methods to manage the associated manufacturing considerations.
2Reliability
If conventional packaging structures are used, then device complexity is reduced, but hermeticity deteriorates
Solution Approach 1:
The patent uses composite material structures (copper-stainless steel-copper) that inherently provide both mechanical strength and hermetic sealing capability. The metallurgical bonding between layers creates a hermetic barrier while the structure remains relatively simple compared to multi-component sealing systems.
Solution Approach 2:
The invention applies hermetic sealing features specifically at critical locations where moisture and contaminants could penetrate, rather than requiring complete structural complexity throughout. The package lid and base interfaces are designed with localized hermetic features that provide effective sealing without overall structural complication.
3Temperature
If high thermal conductivity materials are used, then thermal dissipation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs intermediate bonding layers and fabrication processes that mediate between the high-precision requirements of bonding copper components and conventional manufacturing capabilities. Thermal interface layers and controlled bonding procedures serve as intermediaries that achieve reliable thermal pathways without requiring extreme manufacturing precision.
Solution Approach 2:
The invention changes material parameters (thermal conductivity, mechanical properties) of packaging components while providing corresponding fabrication methods that adjust processing parameters to match these material changes, thereby managing precision requirements through coordinated material and process selection.
4Reliability
If existing RF package designs are used, then ease of manufacture is maintained, but thermal dissipation and hermeticity requirements are not met
Solution Approach 1:
The patent replaces conventional single-material packaging structures with composite material systems (copper-stainless steel-copper) that simultaneously deliver enhanced thermal dissipation and hermeticity. The fabrication methods integrate these composite materials using established metallurgical techniques, balancing improved reliability with manageable manufacturing complexity.
Solution Approach 2:
The invention creates package components that perform multiple functions simultaneously: the copper-stainless steel-copper structure provides thermal conduction, mechanical strength, corrosion resistance, and hermetic sealing in a single integrated component rather than requiring separate elements for each function.
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 configuration effectively manages heat flux, enhances RF performance, and ensures hermeticity, enabling the package to withstand environmental conditions without board-level washing, thus improving reliability and longevity.
Implementation Method 1
The package lid is thermally coupled with the die structure and the package base. The package lid comprises a hermetic material having a thermal conductivity of at least 180 W/(m·K).
Implementation Method 2
The first thermal interface layer comprises at least one of sintered gold, sintered silver, or sintered copper. The second thermal interface layer comprises at least one of sintered gold, sintered silver, or sintered copper.
Data Source
AI summary
The present disclosure provides a packaging device and a method to form the packaging device. The packaging device includes a package base, a die structure disposed over the package base, and a package lid over the die structure. The package lid is thermally coupled with the die structure and the package base.