There are a number of technical challenges unique to fine pitch wire-bond process. It includes a broad mix of component technologies. A typical package may contain 200 different components ranging in size from (.008 inch X .008 inch) and .004 inches thick to (.500 inch X .500 inch). The sheer number of different sized chips and tight chip-to-chip spacing create problems in accessing the bond pads. Fine pitch wire-bonding is of particular importance in the manufacturing of these devices. Fine pitch is defined as 100 microns or less center-to-center distances between bond pads. Many devices use the latest high performance chips that typically include 4 mil pitch bond pads. Innovations in tool configurations, machine vision systems and wirebonding ultrasonics have been critical to improved fine pitch wedge bonding.
The US/UT design incorporates all the latest technical features in semiconductor wire bonding tool designs and is widely used by every bonder manufacturer in the world. The 60º heel with the more squared back or radius area normally will produce a short tail. This tool style is most commonly used where fine pitch bonding is not required.
Chip-On-Board technology is successfully used to connect semiconductors to PCBs for high integration of electronic systems or microsystems. General conditions and procedures of chip and wire bonding are highly developed for standard applications, but new materials , increasing pin numbers, complex system integration processes and demands for higher reliability in low cost throw-away assemblies and more expensive profile-critical products has led to required improvements in the material, design and life of the tool.
SPT has developed tools in partnership with key OEM's to meet these demands
The ABT design is the most widely used and recommended tool design for automatic, manual with automatic retrofit and manual ultrasonic wedge bonders due to its highly Accurate bond placement capability.
The back radius area is rounded which keeps the wire in the center of the tool. The lower back heel area of 38° produces a strong first bond transition.
Microwave devices commonly have bonding pads as small as .001”/ 25µm square. They are typically bonded with .0005”/13µm to .001”/25µm diameter gold wires. Microwave devices have some special requirements that are not seen in monolithic devices special requirements include the variety of chips within the package, step heights within the products that require deep access requirements, as well as critical loop shapes for tuning of the device. We have developed a range of tools to meet the small foot print, and critical loop requirements.
See: Small / Large Wire Shank Styles (PDF, 69KB)