Dennis Rodier

VIISta 900 3D: Advanced medium current implanter

The continued advance of semiconductor technology, including the emergence of 3D device architectures, demands ever-increasing precision of dose and angle control in ion implantation. The Varian Semiconductor Equipment business unit of Applied Materials has enhanced the design of the industrys leading medium current implanter to meet the production requirements of advanced technology nodes. Improvements to the implanter architecture include more precise angle control, increased beam utilization, better uniformity and repeatability and longer maintenance intervals. Advanced ion optics allow measurement and control of beam shape.

Cryogenic ion implantation near amorphization threshold dose for halo/extension junction improvement in sub-30 nm device technologies

We report on junction advantages of cryogenic ion implantation with medium current implanters. We propose a methodical approach on maximizing cryogenic effects on junction characteristics near the amorphization threshold doses that are typically used for halo implants for sub-30 nm technologies. BF2+ implant at a dose of 8×1013cm−2 does not amorphize silicon at room temperature. When implanted at −100°C, it forms a 30 - 35 nm thick amorphous layer. The cryogenic BF2+ implant significantly reduces the depth of the boron distribution, both as-implanted and after anneals, which improves short channel rolloff characteristics. It also creates a shallower n+-p junction by steepening profiles of arsenic that is subsequently implanted in the surface region. We demonstrate effects of implant sequences, germanium preamorphization, indium and carbon co-implants for extension/halo process integration. When applied to sequences such as Ge+As+C+In+BF2+, the cryogenic implants at −100°C enable removal of Ge preamorphiza...

Next Generation Medium Current Product: VIISta 900XPT

Device fabrication requirements for 32 nm and 28 nm technologies further increase the demands on medium current implanters for higher process quality as well as for increased productivity and flexibility. Angle control requirements continue to become more stringent with scaling of device geometries. Pressure for reduced CoO drives the need for higher productivity and this, in turn, drives requirements for tuning time with precise angle control that are substantially more aggressive than for older generation tools. Additionally, dose control and defect control standards have become more demanding. We discuss these requirements in more detail and describe the improvements that have been made to Varian’s next generation medium current tool in order to meet them.

Next Generation Angle Control for Medium Current and High Energy Implanters

Angle control continues to increase in importance with device scaling. For instance, threshold voltage and on‐state current in advanced logic devices depend critically on the angle accuracy of medium current halo implants. TCAD simulation results, showing that on‐state current changes of greater than 1% per degree of implant angle are possible, are presented. We report here on improvements to angle performance and control in both the horizontal and vertical directions. Beam data covering the full operating space of the VIISta 900XP is presented, demonstrating total angle control of better than ±0.2°. The data set is chosen to emphasize performance of typical halo implants. Single wafer high energy angle control data is also presented.

Maximizing Productivity for Well Implantation

Until recently most semiconductor manufacturers have used high‐energy ion implanters for deep well formation. This was partially driven by the fact that these well implants were beyond the productive operating range of conventional medium current implanters to achieve in a productive and cost effective fashion. Recently, VSEA has increased the energy range of the VIISta medium current implanter to 300keV, 600keV and 900keV for single charge, double charge and triple charge implantation, respectively. A combination of this new capability with a reduction in well implant energies due to device scaling, has brought most well implants in the regime of the VIISta 900XP system. This paper describes the superior process performance that is achieved and how this capability results in increased productivity and reduced cost of ownership.