General Plasma Inc.

APT has invented a new source to accomplish High Rate, Uniform PECVD on flexible substrates. This new high density plasma source is called the Penning Discharge Plasma™ (PDP™) Source. The features and benefits of the PDP source are listed below and pdf files of conference papers on this break through technology can be download from the pdf links. Contact APT to discuss how this technology can solve your thin film coating challenges today!

High Deposition Rate
As illustrated in the experimental results, the PDP source achieves high deposition rates at low powers. There are several reasons for this:

Between the two lobes of the Hall current, in the center of the gap, is a void that can be viewed as a virtual cathode. When ions are formed in the Hall current ring, they ‘see’ this virtual cathode and are accelerated into the central gap region. The combination of the electron Hall current confinement and the central ion flow creates a dense plasma in the gap between the rollers with charged particle densities approaching 10¹² charged particles per cm³. This dense and energetic plasma is directly adjacent to the substrate and results in a high condensable species arrival rate on the substrate.
The plasma is formed between the web covered rollers, distant from other electrode or chamber surfaces. This means that the majority of condensable species end up on the web rather than on exposed electrodes or other non-substrate surfaces.
The low plasma impedance allows operation at low pressures. By operating in the low mTorr region, the free mean path is sufficient to minimize gas phase chemistry and powder formation. This permits higher monomer delivery rates and high power operation. This is key to enabling extremely high deposition rates.

Deposition and Morphology Uniformity
The facing cathode electrodes and dipole magnetic field confine the electron Hall current in the center of the gap. This produces a uniform plasma enabling uniform coating of wide web substrates. The uniformity obtained is analogous to a magnetron sputter cathode, as the same Hall current confinement principle is at work. In a magnetron sputter cathode, the racetrack Hall current allows architectural glass over 3 meters wide to be coated with better than 5% uniformity. Though the Hall confinement of the PDP source is distant from the cathode surface, the same fundamental benefit of a constant impedance plasma over the full source applies. This is an improvement over existing PECVD source technologies.

High Rate PECVD on Flexible Web Materials APT has invented a new source to accomplish High Rate, Uniform PECVD on flexible substrates. This new high density plasma source is called the Penning Discharge Plasma™ (PDP™) Source. The features and benefits of the PDP source are listed below and pdf files of conference papers on this break through technology can be download from the pdf links. Contact APT to discuss how this technology can solve your thin film coating challenges today! High Deposition Rate As illustrated in the experimental results, the PDP source achieves high deposition rates at low powers. There are several reasons for this: Between the two lobes of the Hall current, in the center of the gap, is a void that can be viewed as a virtual cathode. When ions are formed in the Hall current ring, they ‘see’ this virtual cathode and are accelerated into the central gap region. The combination of the electron Hall current confinement and the central ion flow creates a dense plasma in the gap between the rollers with charged particle densities approaching 10¹² charged particles per cm³. This dense and energetic plasma is directly adjacent to the substrate and results in a high condensable species arrival rate on the substrate. The plasma is formed between the web covered rollers, distant from other electrode or chamber surfaces. This means that the majority of condensable species end up on the web rather than on exposed electrodes or other non-substrate surfaces. The low plasma impedance allows operation at low pressures. By operating in the low mTorr region, the free mean path is sufficient to minimize gas phase chemistry and powder formation. This permits higher monomer delivery rates and high power operation. This is key to enabling extremely high deposition rates. Deposition and Morphology Uniformity The facing cathode electrodes and dipole magnetic field confine the electron Hall current in the center of the gap. This produces a uniform plasma enabling uniform coating of wide web substrates. The uniformity obtained is analogous to a magnetron sputter cathode, as the same Hall current confinement principle is at work. In a magnetron sputter cathode, the racetrack Hall current allows architectural glass over 3 meters wide to be coated with better than 5% uniformity. Though the Hall confinement of the PDP source is distant from the cathode surface, the same fundamental benefit of a constant impedance plasma over the full source applies. This is an improvement over existing PECVD source technologies. The PDP Source in Operation

		Simple animation of the Penning Roll Source with red lines representing the electric field, blue area representing the magnetic field, and the green ball representing an electron.
		Low Temperature Process The PDP source is a low impedance plasma that operates at low pressures (10mTorr). This results in low neutral particle and ion temperatures and high electron temperatures. The neutral particle and ion temperatures are close to room temperature. The high electron temperature efficiently produces radicals and ions for deposition. A second characteristic of the PDP source is, unlike parallel plate RF, the dual cathode and magnetic field configuration minimizes hot secondary electron bombardment on the substrate. The result is high rate, high power PECVD at reduced substrate temperatures. Roll to Roll (R2R) Production Capable Process When electrodes and other surfaces are exposed to the plasma, the subsequent coating buildup can change the process over the run and requires high maintenance. This is especially true in an R2R coating process that can not cycle through an etch-back after coating each substrate. In the case of the PDP source, the electrodes are substantially covered by the substrate allowing full rolls of material to be consistently coated. Several Technical Papers have been presented on this revolutionary, Patent Pending Technology. The links below point to pdf files of two recent publications: "High Rate PECVD Source for Flexible Substrates" presented at the SVC 2003 Conference "Packaging Barrier Films Deposited on PET by PECVD Using New High Density Plasma Source" presented at the SVC 2004 Conference