Search

The ion beam is neutralized by interactions with the gas molecules present in the process chamber during wafer implant, and thus pressure compensation of this neutralization is necessary to deliver the proper dose. The parameters necessary for pressure compensation have traditionally been determined by implanting a matrix of monitor wafers with various recipe parameters. This paper describes a new method for accurately determining these factors with fewer implants. The new method is faster, much less expensive and is more immune to systematic errors in the implanter and post processing. This procedure has been used to generate tables of pressure compensation factors for several Axcelis high current platforms, and offers improvements to SPC collection at customer sites.

The ion beam is neutralized by interactions with the gas molecules present in the process chamber during wafer implant, and thus pressure compensation of this neutralization is necessary to deliver the proper dose. The parameters necessary for pressure compensation have traditionally been determined by a matrix of implants with various parameters. This paper describes a new method for accurately determining these factors without any wafer implants. The method involves measuring the beam neutralization that results from an intentionally created pressure ramp in the process chamber. Results will be shown for pressure compensation of shower gas mixtures. The method can be extended to photoresist outgassing using special mixtures of gases chosen to simulate the outgassing from photoresist. The new method is faster, much less expensive and is immune to nonimplant processing effects.

Deceleration is used in several new implanters to produce large fluxes of low energy ions, but charge exchange in the beamlines produces energy contamination. We have found that several issues must be addressed to obtain confident estimates of the energy contamination. Pre-amorphized wafers are used to eliminate channeling effects. A least squares fitting method is described that uses multiple drift mode reference profiles accommodate SIMS artifacts and variability. The limitations and accuracy of the method will be discussed.

Antiprotons in the debuncher ring at Fermilab have been observed to be bunched outside of the "barrier bucket" when cooled to small /spl Delta/p/p with the stochastic cooling. This bunching occurs in the same location as a very small stable bucket in the RF wave form. The stochastic cooling appears to be causing a beam that is originally uniformly distributed to be captured by this stable bucket. >

Results are shown of calculations and measurements of the effectiveness of the betatron stochastic cooling systems in the debuncher ring of the antiproton source at Fermilab. This system cools each batch of injected antiprotons from ca. 8/spl pi/ mm mrad to less than 1/spl pi/ mm mrad rms emittance in the 2.4 seconds between production cycles. The conclusions concerning future improvements are summarized. >

With the emergence of production capability for sub-keV ion implant, aspects of the process that were never important before start to play a central role. This paper demonstrates the effects of native oxide on the dopant profiles that result from sub-keV implants. The native oxide has a strong influence via several mechanisms: dopant deposition into the oxide, scattering of the incident beam by the oxide and changes to the beam backscatter. These effects are very important for process designers working in the sub-keV regime.

International audience; The beam experiments of Final Focus Test Beam (FFTB) started in September 1993 at SLAC, and have produced a 1.7 μm×75 nm spot of 46 GeV electron beam. A number of new techniques involving two nanometer spot-size monitors have been developed. Several beam diagnostic/tuning schemes are applied to achieve and maintain the small spot. This experiment opens the way toward the nanometer world for future linear colliders

The Final Focus Test Beam (FFTB) project at SLAC is a demonstration of the feasibility of making the extremely small spot sizes needed for future e/sup +/e/sup -/ linear colliders. Fermilab joined the FFTB collaboration in late 1993. This paper describes the Fermilab contributions to FFTB, emphasizing the work on lattice diagnostics.

High-energy ion implanters using RF acceleration have advantages over electrostatic implementations. However, beam energy from such systems is not simply related to DC voltages as it is in electrostatic systems. Traditionally, energy control in these machines relies on beam collimation from a final energy magnet. Axcelis has developed a novel approach that calculates the energy from the time delay of pulses generated by two spatially separated beam current probes. The compact and cost-effective design is based on a precision, programmable delay line and a unique pulse correlation technique. The prototype hardware has yielded a delay resolution and repeatability of better than p100 picoseconds. Absolute energy calibration of the system is established through a nuclear interaction measurement. This patented Time-of-Flight (TOF) methodology has demonstrated the potential for