Low Profile BGA Package with Exposed Die for Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional BGA packages face issues with high package profile, poor thermal performance, and long electrical interconnection paths, leading to reduced reliability and assembly yield.
Innovation Solution
The IC die is mounted within a central window opening of the substrate, allowing for reduced mold thickness, direct thermal contact with the circuit board, and a shorter wirebond length, with encapsulating material sealing the die and wirebonds while exposing the bottom surface for soldering, and optionally using mini solder balls for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the IC die is attached directly to the top surface of the substrate, then the electrical connection is established, but the package profile becomes high and thermal performance deteriorates
Solution Approach 1:
The IC die is extracted from direct contact with the substrate by mounting it within a window opening, allowing the bottom surface of the die to be exposed for direct thermal contact with the circuit board while maintaining electrical connections through wirebonds to contact pads on the substrate
Solution Approach 2:
The die mounting approach transitions from a planar attachment on the substrate surface to a three-dimensional configuration where the die is positioned within a window opening, enabling thermal contact in one direction (bottom surface to circuit board) while electrical connections extend in another direction (bond pads through wirebonds to contact pads)
2Reliability
If wirebonds are used to connect bond pads of IC die to printed circuit on substrate, then electrical connection is achieved, but the electrical interconnection path becomes long
Solution Approach 1:
The window opening is positioned to optimize the distance between the IC die and the substrate contact pads, locally minimizing the wirebond length while maintaining the overall package structure. The opening acts as a localized feature that reduces interconnection path length without affecting other package dimensions
3Reliability
If the IC die is mounted directly on the substrate, then assembly is simplified, but thermal performance and reliability deteriorate due to contact stress
Solution Approach 1:
The IC die is extracted from direct contact with the substrate by mounting it within a window opening, eliminating mechanical contact stress between the die and substrate while maintaining electrical connections through wirebonds. This separation removes the source of reliability issues associated with direct mounting
Solution Approach 2:
The window opening structure acts as an intermediary that allows the IC die to be positioned above the substrate without direct contact, enabling thermal contact with the circuit board while preventing mechanical stress transmission between the die and substrate
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 reduces package height, improves thermal and electrical performance, enhances reliability by eliminating direct contact stress, and increases assembly yield through improved bonding and heat dissipation.
Implementation Method 1
direct thermal contact with the circuit board
Implementation Method 2
enhanced heat dissipation
Data Source
AI summary
Methods and apparatuses for improved thermal, electrical and/or mechanical performance in integrated circuit (IC) packages are described. An IC circuit package comprises a substrate having a central opening. An IC die, resides within the opening in the substrate. Wirebonds couples a plurality of bond pads on a top surface of the IC die to a plurality of bond fingers on a top surface the substrate. An encapsulating material encapsulates at least the IC die and the wirebonds such that at least a bottom surface of the IC die is left exposed. The encapsulating material suspends the die such that at least a portion of the die is held within the opening in the substrate.