Anthony Renau

A better approach to molecular implantation

A new approach to molecular implantation is presented. This is based on the use of carborane, a large and thermally stable boron molecule that can be ionized in a standard ion source. The modifications that are needed to allow it to run on a Varian VIISta HCS high current tool are discussed. Data is presented to show that the tool can use carborane for high productivity, energy contamination free boron implants. Data is also presented to demonstrate that this additional capability does not change the tools performance for other species and implants. The operation of the tool is described along with productivity and process data for 32 nm logic applications. Electrical data is also presented that illustrates excellent device performance.

Device performance and yield — A new focus for ion implantation

Recent innovations in ion implantation technology that overcome scaling barriers at 32nm/22nm are reviewed. Some of the hardware improvements will be discussed, but the main focus will be on the process and device data that demonstrates their advantages. These innovations include a cryogenic implant capability that enables a significant reduction in implantation induced crystal damage, molecular implants that show device performance improvements and that use standard ion sources, and various approaches that improve implant performance, particularly when diffusion-less anneal is used.

Approaches to USJ Formation Beyond Molecular Implantation

As junction depth requirements approach sub 10 nm and the sensitivity to residual implant damage continues to increase, the capability to produce abrupt, shallow profiles while maintaining low residual damage becomes a difficult challenge. Implantation induced amorphization has been widely applied to reduce channeling tails of implanted dopant profiles for integrated circuit manufacturing. This has been required to meet aggressive junction depth targets. The problem, however, is that pre‐amorphization creates high defect densities that remain near the former amorphous‐crystalline interface post anneal. These end of range (EOR) defects become of greater concern as the industry begins to move towards millisecond anneal technologies. Millisecond anneal, while capable of close to diffusionless activation and abrupt junctions, has caused concern for its inability to fully repair these EOR defects. There has been a recent focus on removing traditional PAI through molecular implantation with limited success. Tow...

Performance characteristics of the Varian VIISta 810 single wafer medium current ion implanter

The design of the VSIIta 810 medium current implanter successfully addresses the needs of advanced semiconductor manufacturing by meeting the challenges of high productivity and reduced defect density. Data are presented verifying that the beamline design reduces the risk of defect production from particulate and metallic contamination while ensuring energy parity. Tuning time, reliability, dose uniformity and repeatability data demonstrate high productivity of the VIISta 810 for a wide range of energies, charge states and implant species for 200 mm and 300 mm wafers.

Directed ribbon-beam capability for novel etching applications

The authors describe a new directed ribbon-beam system capable of a combination of plasma-based processing with that of a ribbon-ion-beam implantation system. In particular, the authors describe how they are utilizing this system for novel reactive-ion-etching processing with high directionality in the planes perpendicular to the wafer surface and at angles non-normal to the wafer. Examples are shown on nanopatterned structures. The authors demonstrate how these results and capability can solve several problems in current and future device patterning.

Evolution of directed ion beams from doping to materials engineering

We review recent changes to implanter processing capabilities, including the adoption of cryogenic implants to reduce leakage and contact resistance as well as high temperature implants for finFETs. We discuss some specific 3D challenges and introduce a new process technology for 3D that uses directed ion beams for material modification including implant, etch and deposition.

The Effect of Amorphization Conditions on the Measured Activation of Source Drain Extension Implants

Un‐patterned wafers were processed using low‐dose Indium or medium‐dose Germanium pre‐amorphization implants (PAI) followed by p‐type dopant implants of BF2 or carborane (CBH). The wafers were then annealed by RTA (spike), laser anneal (LSA) or combination of LSA and spike. Active dopant distributions calculated from SIMS and sheet resistance measurements compared favorably with those determined by differential Hall, which is a challenging technique for shallow profiles. The trends in B diffusion behavior and activation are discussed in relation to the different implant damage budgets, damage evolution during the anneals and presence of fluorine. In particular, for low thermal budget LSA only anneals, CBH implants appear to give higher activation than BF2 due to the absence of fluorine.

High-Uniformity Inductively Coupled Plasma Source With Magnetic Multicusp Confinement

A high-uniformity inductively coupled plasma source is presented. The plasma uniformity is improved with a magnetic multicusp structure that surrounds the plasma chamber. A picture showing the alternating bright and dark plasma regions along the perimeter of the plasma chamber-an effect of the magnetic confinement-is presented as well.

Reliability Tests of a Real Time Charge Monitor (RTCM)

Wafer charging effects that result from the ion implantation process are typically mitigated by employing a plasma flood gun to provide electrons to neutralize the positive ion beam as it strikes the wafer surface. As gate oxide thickness of semiconductor devices continues to shrink, control of the wafer charge‐up during ion implantation becomes critical. Varian Semiconductor Equipment Associates (VSEA) has designed and built a real time charge monitor (RTCM) for in situ measurement of the beam‐induced charging potential. Mounted close to the wafer and in the beam path, the RTCM continuously measures the deviation from quasi‐neutrality as the wafer passes through the beam. In this paper we present reliability tests of this device for high current implanters over varied implantation conditions and failure modes. When correlated with the yield of antenna device test wafers, it was found that the RTCM signal is a sensitive and reliable tool to predict charging damage to the semiconductor devices.

Benefits of Zero Degree Single Wafer High Energy Implants for Advanced Semiconductor Device Fabrication

High energy well implants for retrograde well formation are usually tilted to avoid channeling. However, this can cause the well profile under the STI (Shallow Trench Isolation) to be skewed or asymmetric due to shadowing by the resist. This results in poor inter‐well isolation and increased leakage currents. This problem becomes more pronounced below 65 nm design rules. In this paper, using experimental data and TCAD simulations we demonstrate the improvement in inter‐well isolation and junction characteristics that can be achieved with true‐zero well implants. Finally, we briefly discuss the corresponding die shrinkage that can be expected.