Nobuo Nagai

Wafer chargeup study on the PR-80 high current ion implantation machine

Abstract Reduction of the wafer chargeup in the PR-80 high current ion implantation machine has proceeded by using an electron shower in its Faraday system. The wafer disc current which represents the sum of the charge flow of an ion beam and an electron flux was treated separately as a feedback signal to the shower control circuitry. The disc current was kept at a prescribed value during implantation. The breakdown or degradation of SiO2 gate structures were investigated as a function of the disc current, using the TEG (Test Elements Group) wafer.

High performance medium current ion implanter system EXCEED3000AH‐G3

A new medium current ion implanter has been developed based on the EXCEED3000, which is highly reliable and widely used in 300mm fabs. The ion implanter now has to be designed so that it can precisely measure and control beam characteristics. For example beam angles have to be controlled in halo implantation because high tilt angle implantation is done according to the device geometric structure. Not only horizontal beam profile system but also vertical beam profile system are implemented in EXCEED3000AH‐G3 for the precise implantation control.

Suppression of phosphorus diffusion using cluster Carbon co-implantation

Phosphorus transient enhanced diffusion (TED) is caused by interstitial diffusion mechanism. It is important for the efficient suppression of phosphorus diffusion that some carbons could be located on lattice point in the initial stage of re-growth during annealing and trap interstitial Silicon. Carbon co-implantation after Germanium, pre-amorphization implantation (PAI) is applied for the applications of n+/p junction formation and the effects of Carbon co-implantation are reported. In our experiments it is shown that suppression of Phosphorus diffusion could be achieved with conventional rapid thermal annealing (RTA) by using cluster Carbon (C16Hx+, C7Hx+) co-implantation for the self-amrphization. Our experimental data suggests that cluster carbon co-implantation enable to suppress phosphorus diffusion without germanium pre-amorphous implantation. In this paper the characteristics of cluster Carbon co-implantation after RTA are introduced from experimental results which were obtained by secondary ion mass spectroscopy (SIMS) measurement, transmission electron microscopy (TEM) and sheet-resistance measurement.

Cluster Ion Implantation System: Claris for Beyond 45nm Device Fabrication (Ii)

Newly developed sweep beam Cluster ion implanter: CLARIS with 0.2-7keV energy range for Boron beam and 1-10keV energy range for Carbon beam is introduced. Novel Cluster ion implantation technology is capable for 45nm beyond device requiring USJ formation ( 70%) and low sheet resistivity (<1200Ω/sq). Comparison of retain dose and sheet resistivity of B18, BF2, and B beams with FLA shows the superiority of the B18 implantation for less than 500eV implantation.

Development of Nissin new boron cluster ion implanter

New boron cluster ion implanter is being developed with using alpha-type equipment. High through-put at ultra low energy region in drift mode with good implantation qualities is confirmed and presented. We continue to develop this cluster ion implantation technology for mass production.

PR-80 high current ion implantation machine

Abstract A high current ion implantation machine, PR-80 has been developed for production line use in semiconductor device fabrication. PR-80 provides an ion beam of 13 mA for both phosphorus and arsenic, and 5 mA for boron at an energy between 40 and 80 keV. For much demanding boron beam production at lower energy, PR-80 offers a reliable 2 mA beam at 10 keV. A fully automated dual end station incorporates the load-lock, a belt transfer mechanism, and a wafer disc which is always kept in a high-vacuum chamber in order to keep the dust particles sticking to wafers to a minimum. These features offer users clean and fast wafer handling. The throughput guaranteed for 6 in. wafers with a 10 mA beam at 1 × 1016 ions/cm2 dosage is 60 wafers/h. A deionized-water-cooled wafer disc and an electron beam-tailored-rubber pad keeps the wafer temperature rise well below 100°C with a 700 W beam at 1 × 1016 ions/cm2 dosage. One of effective means to reduce wafer charge buildup during implant is to get an ion beam of larger dimension, thus decreasing the intensity of ionic charge flow. This is achieved either by adjusting the rotatable pole tip at the exit of analyzing magnet or by using the beam expanding electrode unit. The beam can be broadened to 35 mm × 110 mm at the target.

Improvement of productivity by cluster ion implanter: CLARIS

The cluster ion beam implanter named CLARIS has been developed for beyond 45nm device production use, which is characterized by the high productivity, high effective low energy high current, and preciseness of incident beam angle and dose uniformity. For the USJ process application, a cluster beam co-implantation is introduced. Carbon cluster co-implantation and the boron cluster beam implantation productivity are evaluated from a COO and CoC view point and compared with the conventional high current implanter.

Implant dose uniformity simulation program

Abstract A two-dimensional implant dose uniformity simulation code consisting of two programs named SCAN and MAP has been developed. The code can take account of the effects of beam sweep waveform, beam sweep frequency, beam size, and wafer rotation speed. The result of the calculations can be plotted in a two-dimensional contour map similar to a wafer uniformity map.

Cluster Ion Implantation for beyond 45nm node novel device applications

This paper describes the applications of cluster ion implantation for beyond 45 nm node novel devices. A) Metal/high-k MOSFET: a flash lamp annealing (FLA) has advantage of dopant diffusion-less characteristics, but it requires suitable angle control for optimum gate overlap length. Cluster boron implantation with tilted SDE implantation for p-FETs has superiority over monomer boron implantation with Ge PAI (pre-amorphous implantation) in terms of VTH roll-off s and ion-ioff s if FLA is used as activation anneal. Full-metal-gate HfSiON transistors whose gate length is less than 50 nm are fabricated with superior electrical characteristics. B) n-MOS stress engineering: Si:C formation with high carbon substitution has been obtained using cluster carbon implantation and msec annealing which leads to higher stress in the channel region. C) Fin-FET: high tilt angle with low energy boron cluster ion implantation is found to improve the retained dose compared to monomer boron. It is suitable for Fin-FET implantation applications.

Ion implantation technology and system for beyond 45nm node devices

Beyond 45 nm node transistor device transition is reviewed and the compensation for Moor¿s scaling law, next generation transistor structure and material will be changed. Accordingly, the ion implanter should be changed for the suitable production efficiency and new functions. The Medium Current ion implanter energy range was changed for the total low cost performance. The Low Energy ion implanter is appeared for miniaturization of the semiconductor devices. It will be developed for novel requirements of the devices.