Luke Hoefer, KyungSu Kim
Amkor Technology Inc.
2045 E. Innovation Circle
Tempe, AZ 85249 USA
Abstract
The demand for cost-effective leadframe packages continues to grow, particularly for automotive and
commercial applications. These designs require smaller form factors, enhanced thermal and electrical
performance, and proven reliability. Flip chip on leadframe technology offers significant advantages over
traditional wire-bonded MicroLeadFrame® (MLF®) and high-cost laminate Flip Chip Chip Scale Package
(fcCSP) designs, including enhanced thermal and electrical characteristics and reduced package size
compared to traditional wirebond solutions such as MLF®. As industry standards push for cost effective
solutions targeting thinner and more compact profiles than available in wirebond solutions, flip chip
technology enables die size reduction and printed circuit board (PCB) area savings compared to conventional
wire-bonded MLF® packages. The use of copper (Cu) pillar bumps supports fine-pitch designs and offers
flexibility for fan-in leadframe configurations. The flip chip MicroLeadFrame (fcMLF®) package presents a
compelling solution for a wide range of applications, including power management integrated circuits
(PMICs), DC/DC converters, and RF switches. As with a traditional MLF® package, Amkor’s wettable flank
feature, both dimple and step-cut configurations can be supported. A requirement of the automotive industry,
the wettable flank enhancement enables Automated Optical Inspection (AOI) for proper fillet formation
during the Printed Circuit Board (PCB) solder reflow process without requiring an expensive and complex
through board X-Rays process. By leveraging industry-leading flip chip interconnect technology and an
established sawn MLF® manufacturing process, fcMLF® packaging delivers a cost-effective, high
performance leadframe packaging solution tailored to meet the evolving needs of modern electronic systems.
Keywords
Cost Effective, Copper Pillar, fcMLF®, Side Wettable Flank, Size Reduction, Thermal Efficiency
