Flip Chip Package with Exposed Backside Metal Heat Dissipation
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Solution Overview
Problem
Flip chip packages face challenges in heat dissipation, particularly in high pin count and fine pitch applications where traditional lead frame based packages are not suitable, limiting their use in compact, high-speed electronic products.
Innovation Solution
A flip chip package structure featuring a lead frame with exposed backside metal for heat dissipation, where the chip is placed under the lead frame and encapsulated, allowing direct heat transfer to the ambient environment through the exposed backside metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional lead frame based package is used, then manufacturing is simpler and cost is lower, but heat dissipation capability is insufficient and it is limited to low-end applications
Solution Approach 1:
The package structure is segmented into distinct functional zones: the lead frame provides electrical connection and structural support, the chip mounted thereon performs signal processing, and the exposed backside metal of the chip provides dedicated heat dissipation. This segmentation allows each component to optimize its specific function without compromising overall performance.
Solution Approach 2:
The invention transitions from traditional planar heat dissipation to three-dimensional heat management by exposing the backside metal surface of the chip. This creates an additional heat dissipation dimension perpendicular to the chip plane, enabling effective thermal management in compact high-pin-count packages where conventional approaches fail.
2Reliability
If flip chip package is used for high pin count and fine pitch applications, then signal interference is reduced and electrical properties are improved, but heat dissipation becomes challenging
Solution Approach 1:
The chip's own backside metal, which would normally be buried or covered in traditional packages, is utilized as the heat dissipation structure. This self-service approach transforms an unused or passive surface into an active thermal management component, enabling the flip chip package to self-regulate heat without requiring external cooling mechanisms.
3Temperature
If backside metal is exposed for heat dissipation, then thermal management is improved, but package structure becomes more complex
Solution Approach 1:
The encapsulant is strategically withdrawn or removed from the backside metal region of the chip, extracting only the necessary portion to expose the thermal management surface. This selective extraction allows heat dissipation while maintaining encapsulation protection for the electrical connection areas, balancing thermal performance with structural integrity.
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 enhances heat dissipation while maintaining low signal interference and good electrical properties, ensuring stable operation in high pin count and fine pitch applications.
Implementation Method 1
a lower surface provided with a backside metal for heat dissipation
Implementation Method 2
allowing direct heat transfer to the ambient environment through the exposed backside metal
Data Source
AI summary
A flip chip package structure includes a chip placed under a lead frame, a bump on the upper surface of the chip that is electrically connected to the lead of the lead frame, and a backside metal on the lower surface of the chip that is exposed outside an encapsulant encapsulating the chip and a portion of the lead frame.