Flip Chip Lead Frame Package With Lead Tip Hole
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Solution Overview
Problem
Existing flip chip integrated circuit packages face challenges in reducing package height, increasing pin count, and lowering costs while maintaining robust electrical performance and high manufacturing yield, as they often result in uneven solder flow, contamination, and increased complexity due to the use of lead frame and solder bump technologies.
Innovation Solution
The solution involves forming lead fingers from a lead frame, creating a lead tip hole, mounting an integrated circuit die with solder bumps on the lead fingers, and reflowing the solder bumps within the lead tip holes to achieve reliable electrical connections and prevent contamination, thereby reducing package height and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flip chip mounting with solder bumps is used, then electrical connection is achieved, but uneven solder flow and contamination occur resulting in reduced manufacturing yield
Solution Approach 1:
The lead tip hole acts as an intermediary structure that guides and contains the solder bump during reflow. The hole provides a defined cavity that directs solder flow, preventing uneven distribution and contamination. This mediator structure enables consistent solder joint formation while maintaining manufacturing yield.
2Reliability
If lead frame packages with bond wires are used, then electrical connection is achieved, but package height increases
Solution Approach 1:
The invention inverts the traditional connection approach by using solder bumps on the lead frame lead tips instead of bond wires connecting to the die. This inversion allows the die to be mounted in a flip chip configuration with direct solder joint formation, eliminating the need for bond wires and reducing package height.
3Adaptability or versatility
If more integrated circuits are integrated into a single package, then functionality increases, but package dimensions and cost increase
Solution Approach 1:
The invention enables higher density integration by transitioning from planar arrangement to three-dimensional stacking. The lead frame structure with vertical lead tips allows multiple integrated circuits to be mounted in stacked configurations, utilizing the vertical dimension to increase functionality without proportionally increasing package footprint.
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 results in a flip chip lead frame integrated circuit package system with increased reliability, higher pin count, lower package height, and lower costs, along with simplified manufacturing processes, by ensuring consistent solder reflow and preventing delamination issues.
Implementation Method 1
reflowing the solder bump on the lead tip hole of the lead finger
Data Source
AI summary
An integrated circuit package system is provided forming a lead finger from a padless lead frame, forming a lead tip hole in the lead finger, mounting an integrated circuit die having a solder bump on the lead finger, and reflowing the solder bump on the lead tip hole of the lead finger.