AIT II

The AIT II, an advanced system for patterned process tool monitoring for 0.18 µ and smaller geometries, has bridge capability to 300-mm wafers. By enabling the immediate detection of process tool excursions, the AIT II minimizes the number of wafers exposed to out-of-control process conditions, offering integrated circuit (IC) manufacturers the opportunity to save millions of dollars in otherwise lost revenue.

An extension of the company's AIT technology, the AIT II delivers the high throughput, superior sensitivity, and low cost of ownership needed to support the increased process tool inspection needs of advanced device manufacturing, including demanding chemical mechanical planarization (CMP) and etch applications.

By meeting the requirements of process tool monitoring, the AIT II adds a critical new dimension to company's Intelligent Line Monitoring solution. Patterned process tool monitoring, a highly efficient means of monitoring process tool performance, is seeing rapid adoption as a complementary approach to line and yield monitoring. This shift in inspection strategies is being driven by the yield challenges resulting from sub-quarter micron device shrinks.

Patterned process tool monitors inspect product wafers to determine the status and defect contribution of a particular process tool, while line monitors inspect product wafers to determine the overall defectivity of an entire process zone. Yield monitors inspect product wafers from a particular lot throughout the manufacturing cycle and correlate that data to yield.

The AIT II incorporates double-darkfield technology, which combines low-angle illumination with low-angle collection optics. This technology provides superior defect capture by suppressing color variation and grainy background noise, as well as increasing small particle sensitivity and providing surface selectivity to minimize detection of previous layer defects. In the AIT II, this proven illumination system has been further enhanced with a collection area significantly greater than that of the AIT, resulting in increased defect capture.

The improved collection optics optimize the AIT II for CMP and etch process tool monitoring. At the same time, the system's programmable spatial filters (PSFs) enable improved defect collection on array structures, while selectable polarization of the illumination beam provides increased sensitivity by minimizing process noise. The AIT II's ability to vary the die-to-die signal processing threshold and contrast levels for different areas of the device further increases detection sensitivity to particles and pattern defects.

The AIT II also incorporates the new MultiSpot option, which provides multiple laser spot sizes, selectable for increased defect signal-to-noise ratio and throughput optimization. This option is available either when ordering the AIT II or through an easy field upgrade. To ensure high resolution defect classification, the AIT II incorporates KLA-Tencor's IMPACT/Online automatic defect classification (ADC) software. This ADC solution provides rapid time-to-information capabilities and ensures integrated, consistent defect classification across all KLA-Tencor optical patterned wafer inspection tools in the fab.

KLA-Tencor, 160 Rio Robles, San Jose, CA 95134. Tel: 408-875-4200; Fax: 408-571-3030.