SEMICON West is the flagship annual event for the microelectronics industry, with 2012 bringing together 690 exhibiting companies from 21 countries and an estimated 29,000 attendees under one roof.
As described by SEMI, "It is the premier event for the display of new products and technologies for microelectronics design and manufacturing, featuring technologies from across the microelectronics supply chain, from electronic design automation, to device fabrication (wafer processing), to final manufacturing (assembly, packaging, and test). More than semiconductors, SEMICON West is also showcase for emerging markets and technologies born from the microelectronics industry, including micro-electromechanical systems (MEMS), photovoltaics (PV), flexible electronics and displays, nano-electronics, solid state lighting (LEDs), and related technologies."
The energy at the Palomar Technologies booth was reflective of the rebounding strength of the industry and technology advancements. Palomar Technologies displayed live demos of a fully automated, sub-5um placement accuracy (application dependent) die bonder (3800 Die Bonder) and a fully automated, up-to-13.5mm deep access wire bonder (8000 Wire Bonder) throughout the duration of of the exhibition.
Check out the Palomar Technologies SEMICON West 2012 Video Recap!
A reoccuring topic on the show floor dealt with ball bumping capabilities. As the Director of Palomar Technologies' EMEA office, Josef Schmidl, explained in his blog, "One basic requirement is the generation of a repeatable size of a 'Free-Air Ball' (FAB): the start of any ball bonding sequence. The 8000 Wire Bonder is equipped with a unique patented Deep Access Dual Axis Bond Head™. In addition to the linear Z-movement (Zl) for deep access applications, its tilting transducer (Zr) guarantees the precise tail length generation which is necessary to form consistent, repeatable ball bumps."
Overview of Ball Bumping
In wire bonding, a gold ball is forced down and thermosonically bonded to a die-bond pad forming the first connection of an integrated circuit (IC) and substrate. With the ball connected, the wire is fed out and attached to a second surface, and then torn off to complete the connection. In the ball-bumping process, instead of making the second connection with a wire loop and stitch, the wire is removed after the ball is connected to the die. A new ball is formed and the process repeats as necessary on all the die bond pads. Gold-ball bumping can be a one-step process, but can involve two steps if a coining process is needed to planarize the ball bumps. Once the die is completely bumped, it is flipped and attached to the substrate, providing the first-level interconnect as well as protection for the active die surface. These thermosonic or thermocompression bonding methods are often known as microwelding.
Coplanarity, conductivity, thermal properties, size, and reliability are weighted concerns for many engineers. The best answer is often gold-ball bumps. Digital signal processors are presently the largest application for gold bumping. LEDs are also attached with a gold bump and flip process. Large wafers with CMOS image sensors and high I/O counts requiring 30 to 40 bumps, and super-high-frequency RF receivers are other applications. Some applications require 550 bumps on a 2-in-long die that can make a connection in a single flip.
Download Gold Ball Bumping: An Effective Wafer-Bumping Method to learn more.
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Jessica Sylvester
Marketing Communications
Palomar Technologies, Inc.