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Product Briefing Outline: Varian Semiconductor Equipment Associates, Inc. has introduced VIISta ‘SuperScan,' which provides a method of using VIISta medium & high current implanters to compensate for non-uniformity of device electrical characteristics resulting from other semiconductor process steps. SuperScan provides customers with the capability to correct Vt non-uniformity by using ion implantation to compensate for gate length critical dimension (CD) variations. Vt, or threshold voltage, one of the most critical transistor characteristics in device manufacturing, directly impacts chip speed and power consumption. The system is available as an option on the VIISta platform and as an upgrade on installed systems.

Problem: For advanced technology nodes, it is becoming increasingly difficult to consistently achieve uniform radial etch process control and uniform threshold voltage across the wafer. Variation in CD can come from non-uniform etch profiles that result in unacceptable Vt variability. Conventional correction methods add process complexity and steps, increasing costs. Non-uniformity also reduces the number of high performance bin die, limiting revenue per-wafer and non-maximization of yield.

Solution: Using SuperScan, implant engineers can correct radial threshold voltage variation and achieve improved device performance and yield. VIISta SuperScan enables engineers to improve wafer yield by creating a custom dose map, meaning that engineers can adjust the implant so that a central region has more or less dose relative to the outer region by a given amount.  The map has multiple implant zones to define the slope of the gradient and thereby directly reducing the Vt variability. No further process steps are required. A one percent improvement in Vt variability can significantly improve yield and performance bin die category, according to the company.

Applications: VIISta medium current (VIISta 810HP, 810EHP, 810XE, 810XEr, 810XP and 900XP models) and high current (VIISta 80HP, HC, and HCP) models for Halo and S/D processes.

Platform: VIISta SuperScan is designed for production and development applications. The product is available immediately as an option on new VIISta ion implanters, and also as an upgrade for installed systems. All of the VIISta products feature the Varian Control System (VCS), the Varian Positioning System (VPS) and a common single wafer endstation.

Availability: October 2006 onwards.