VIISta® 900 3D

The Varian VIISta 900 3D system is the industry’s flagship medium-current ion implanter for high-volume manufacturing beyond the 2xnm node. Its beam-line architecture has been specially designed with the angle accuracy and beam shape control necessary for exact dopant placement and minimal within-wafer and wafer-to-wafer variability for applications in logic finFETs and 3D memory structures. These capabilities also benefit CMOS image sensor technology as well as the most advanced planar structures.

The system leverages the proven world-class particle performance of the VIISta platform beam-line architecture. A filter magnet removes the majority of unwanted implant species right at the source. Triple-magnet architecture delivers the cleanest beam line available among medium-current systems, removing beam-borne metals, particles, cross-species, and contamination well before the beam reaches the wafer. A unique combination of vertical angle and beam shape controls improve implant precision, and closed-loop micro and macro uniformity metrology minimize implant variability. These controls tighten vertical and horizontal angle accuracy to 0.1º, a two-fold improvement over previous-generation technology.

Controlling crystalline damage is critical to the performance and power consumption of 3D devices. Optional integrated hot-implant capability maintains the crystallinity of silicon and high-mobility channel materials during ion implant. Implants at elevated temperatures eliminate corner and growth defects in 3D structures, increase dopant activation, and reduce defect-induced device leakage. Dose rate control allows the user to further reduce crystalline damage for a given recipe condition.

Enhanced beam shape and dose control make possible optimized SuperScan capabilities that correct non-uniformities from upstream process steps other than implantation. SuperScan 3 algorithms enable custom dose delivery for virtually any desired pattern without having to rotate the wafer.

The integrated hot-implant capability is the key technology of the new VIISta 900 3D system for 150mm and 200mm silicon carbide (SiC) wafers. The dense crystal structure and extreme hardness of SiC makes it extremely difficult to diffuse dopants following implant. To optimize diffusion and activation, the system heats the SiC substrate, which is held by a unique electrostatic clamp to facilitate superior temperature uniformity and mitigate wafer warpage. Optional tilted implant capability up to 60° enables next-generation trench architectures. Production-proven wafer handling on the universal end-station and source design that enables the shortest green-to-green maintenance times in the industry together produce best-in-class productivity.