11/16/2009, Irvine, California

 

Packaging Technology Innovation: Market Return Accelerates Development

Though much of the focus in the IC packaging market throughout 2009 was largely centered on removing supply chain costs, the current recovery will likely be more about advances in IC package design and manufacture rather than cost reduction. Clearly, a rebound from the Q4 2008 – Q1 2009 recessionary low point is happening throughout a wide range of market sectors, but some applications and market segments are seeing a faster acceleration than others.

For example, IC integration, including new wafer-level packaging design, through silicon via (TSV) technology and a multitude of new developments for multi-die and die-stacking processes will drive high-density die packaging technology further and faster than ever before.
With a forward-looking approach to materials innovation, Henkel had forecast these developments and invested significant resources throughout the recession so as to deliver market-ready materials aligned with these packaging technology trends. In fact, Henkel launched over 50 new products in 2009, including a few that we will discuss here:

    •    Epoxy Flux materials
    •    Thermo-compression Bonding materials
    •    Conductive adhesives for photovoltaic module assembly
    •    Compression molding technology
    •    Wafer Backside Coating

All of these materials have the potential to significantly impact the IC packaging and design industry through improved throughput, lower overall production costs and higher yields.

Epoxy Flux materials deliver both a fluxing component to facilitate solder joint formation as well as an epoxy system that provides underfill-like protection. Originally designed for large format CSPs and BGAs, these innovative materials have also proved to be a robust solution for top-level package assembly for Package-on-Package devices, where traditional underfill processes are not feasible. In addition, epoxy flux materials have been shown to offer improved reliability on BGAs when used in place of traditional tacky flux materials for ball attach processes.

Thermo-compression bonding materials are facilitating the use of fine-pitch flip-chip packages for IC packages. Historically, flip-chip devices have relied on solder reflow to form the electrical interconnect, but the risk of bridging has prevented the use solder processes for veryfine-pitch devices. New analysis, however, has shown that thermo-compression bonding in combination with a new NCP underfill material is a successful solder alternative for many very fine-pitch flip chip applications including copper pillar and gold stud flip-chip interconnects. With these materials, bonding can occur in as little as one second. Devices assembled using the new NCP material had 100% yield and passed MSL/HAST performance at most bonding conditions.

Conductive adhesives for photovoltaic module assembly have also been developed by Henkel. While conductive adhesives have been used as an alternative to solder for many applications including satellite, automotive, medical and telecom, their instability on non-noble termination metals such as copper and Sn have limited their use. But recent work has shown that the unstable contact resistance is due to electrochemical corrosion of these metals under elevated temperature and humidity conditions. Based on this knowledge, Henkel developed a new class of conductive adhesives that exhibit excellent contact resistance stability on surfaces including OSP copper, Sn alloys and 100% Sn. These are ideal for use on thin film solar substrates.

Compression molding is emerging as a viable and efficient transfer molding substitute for applications including eWLB, MCP SiP and others. Because compression molding allows a larger area to be molded at one time, throughput is improved and waste is minimized. The compression molding process can also eliminate the use of certain materials as well as process steps for advanced packages. These include the elimination of laminate substrates in several WLCSP packages and underfill processes in FC-CSP packages.

Wafer Backside Coating (WBC) materials and processes for leadframe/power IC packages have also been among Henkel’s development priorities. Unlike traditional die attach processes where the leadframe pad has to be designed significantly larger than the chip to enable flow of the paste and formation of the fillet, WBC allows for tight fillet control for reduced package size and bondline thickness (BLT) uniformity for reduced die tilt. In addition, WBC streamlines processing steps so manufacturing costs can be substantially reduced.

All of these materials innovations align with the technology focus of the ongoing recovery, enabling packaging specialists to advance product development while improving throughput, efficiency and performance. For more information on these latest Henkel products or any of our semiconductor packaging materials, call the company headquarters at 949-789-2500 or log onto www.henkel.com/electronics.