Novel, Robust Anisotropic Conductive Epoxy Technology for Advanced Semiconductor Packaging Applications

M. Ramkumar
SunRay Scientific Inc.,
United States

Keywords: anisotropic conductive epoxy


Advanced packaging is a key element in defining the next generation of semiconductor innovation. It is making possible spectacular new technology solutions to solve many of the world’s most pressing challenges. To achieve these goals, companies and governments will need to determine how to cultivate robust regional advanced packaging ecosystems to support the expected surge in chip production globally” . Leaders of top semiconductor, microelectronic, IC-Substrate, PCB, Electronics Manufacturing Services, and Outsourced Semiconductor Assembly and Test companies along with the U.S. government and European Commission agreed that expanding "advanced packaging" capacities and capabilities related to expanding production of semiconductor chips, as "the next big thing" in CHIPS Act implementation. A new report, sponsored by IPC, recognizes that advanced packaging is increasingly the leading driver of innovation in microelectronics today. Semiconductor chip packaging has expanded from its conventional definition of providing protection and I/O for a discrete chip, to encompassing a growing number of schemes for interconnecting multiple types of chips. Advanced packaging has become integral to embedding increased functionality into a variety of electronics, such as cellular phones and self-driving vehicles, by supporting high device density in a small footprint. Higher density 3D die-to-die, die-to-wafer, or wafer-to-wafer interconnection has been a major industry goal and heterogeneous Integration is seen as an extension of Moore’s Law, to achieve better power efficiency w/finer pitch, shorter lengths. Hybrid bonding reduces lengths to micron scale. A novel anisotropic conductive epoxy solution (ZTACH® ACE), capable of utilizing the standard SMT assembly process, is showing tremendous promise and has demonstrated its capability to replace solder in many advanced semiconductor packaging applications outlined above. Emerging as a viable solution for high density interconnection (HDI), heterogeneous integration (HI), flexible hybrid electronics (FHE) packaging, wafer level packaging (WLP), wire bond replacement, and TSV fill for interposer interconnection, ZTACH® ACE is the next generation of advanced packaging interconnect material. ZTACH® is applied as a paste onto the entire footprint of the device and uses a magnetically induced self-assembly mechanism to align ferromagnetic particles to form the Z-Axis electrical connections in seconds, within a durable matrix. When the “conducting columns” are formed, they carry current only in the Z direction from a conducting region to another conducting region. Flip-chip die and die-to-die bonding, from dense to fine pitch, typically require solder balls and underfills. Underfill and/or edge encapsulant is often utilized to provide additional mechanical strength and stress reduction. The result is a complex assembly process flow. Localized placement of Anisotropic Conductive Adhesive (ACA) or Anisotropic Conductive Film (ACF) for specific components typically involves use of thermocompression bonding, an additional process step that could also be damaging to thin silicon. ZTACH® ACE with its pressure-less and low temperature processing capability enables seamless development towards a wafer scale compatible packaging method. Thermal or UV curing methods complete the component attachment without any thermocompression. Thermal curing occurs within the 80°C to 160°C temperature range.