Metal Film Uniformity

Sheet resistance uniformity of metal films is critical to ensure device performance, and most metal films can be measured by both 4PP and EC. EC is recommended for thicker, highly conductive metal films and 4PP for thinner metal films ( > 10Ω/sq), but very high 4PP/EC correlation ensures accurate results using either method.

The R50 resistivity maps highlight film uniformity, deposition quality, and other process variations. This EC map of a 2μm AlCu film identifies and quantifies an off-center deposition.

Ion Implantation Characterization

4PP is the standard technique for measuring ion implant processes. Mapping an ion implant after thermal annealing can identify hot and cold spots due to lamp failure, poor wafer/platen contact, or implant dose variations. For an ion implanted silicon layer, thermal annealing is required to activate the dopant ions.

In the example at left, the three red (high resistance) spots indicate locations of greatest heat loss during ion (example right) implant anneal due to the three wafer supports. Temperature uniformity is critical for the annealing process, and heat loss at the wafer edge and contact points can be a serious challenge to activation uniformity. Note that for light-sensitive samples, the Filmetrics R54-Series enclosed sheet resistance mapper is generally recommended.

Film Thickness/Resistivity/Sheet Resistance

Measured wafer data can be mapped as sheet resistance, film thickness, or resistivity. By entering a resistivity value for a material, the thickness can be calculated and displayed; the resistivity can be calculated if the thickness value is entered.

Data Acquisition and Visualization

RsMapper is the R50 intuitive user interface that combines data acquisition and analysis features into a single platform that can be used on the tool itself or for offline analysis. Data acquisition for measurement sites can be easily specified using a variety of coordinate layouts.

The RsMapper platform can display the measurement results in either 2D or 3D for quick visualization of critical film uniformity data, as shown for the ion beam scanning issue shown at left. The software easily switches between maps of individual measurement parameters and rotatable 3D profiles to deliver customized views of the process parameters. Whether measuring sheet resistance, resistivity or metal film thickness, RsMapper delivers compelling visual data.