[en] Molecular implantation offers semiconductor device manufacturers multiple advantages over traditional high current ion implanters. The dose multiplication due to implanting more than one atom per molecule and the transport of beams at higher energies relative to the effective particle energies result in significant throughput enhancements without risk of energy contamination. The Optima HD Imax is introduced with molecular implant capability and the ability to reach up to 4.2 keV effective ¹¹B from octadecaborane (B₁₈H₂₂). The ion source and beamline are optimized for molecular species ionization and transport. The beamline is coupled to the Optima HD mechanically scanned endstation. The use of spot beam technology with ionized molecules maximizes the throughput potential and produces uniform implants with fast setup time and with superior angle control. The implanter architecture is designed to run multiple molecular species; for example, in addition to B₁₈H₂₂ the system is capable of implanting carbon molecules for strain engineering and shallow junction engineering. Source lifetime data and typical operating conditions are described both for high dose, memory applications such as dual poly gate as well as lower energy implants for source drain extension and contact implants. Throughputs have been achieved in excess of 50 wafers per hour at doses up to 1x10¹⁶ ions/cm² and for energies as low as 1 keV.

[en] The movement in semiconductor fabrication towards 'islands of automation', combined with the high cost of maintaining installed capital equipment, demands the optimization of implanter utilization. Presently, skilled process engineers are required to regularly setup and adjust implanter parameters. Any reduction in the number of production hours devoted to ion beam implanter setup or recalibration after a species change would represent substantial improvements in both manpower and equipment utilization. (orig.)

[en] The ability to use large molecular species such as octadecaborane (B₁₈H₂₂) has been investigated at semiconductor device manufacturers as a way to significantly increase wafer throughput relative to standard high current ion implanters. Over the past two years, improvements in the machine design to support the use of B₁₈H₂₂ have led to beam current increases of 50% from 30 pmA to 45 pmA of boron at an equivalent boron energy of 4 keV. This boron energy is required by p⁺ doping of dual poly gate (DPG) structures in DRAM. Beam current has also been significantly improved at the low equivalent boron energies anticipated to be required by 32 nm processes for PMOS source/drain extensions (SDE). For example, at 250 eV equivalent beam energy, a 100% increase in cluster boron beam current has been attained.This paper describes the techniques by which these beam current improvements were accomplished, primarily through the refinement of ion beam optics. Other techniques for increasing overall tool productivity are also described, such as beam utilization and overall operational improvements. Wafer throughputs are presented for critical p⁺ implant processes such as dual poly gate (DPG), source/drain (S/D), source drain extension (SDE) and S/D contact. The higher throughputs resulting from these changes are translated into a cost per wafer (CPW) model and it is demonstrated that an increase in average beam current is the largest contributor to a reduction in CPW.