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MAPLE System

Matrix Assisted Pulsed Laser Evaporation (MAPLE) was developed at the Naval Research Laboratory about 8 years ago to deposit polymer thin films.

Overview

The MAPLE Process

In the MAPLE process, a polymer/solvent mix is frozen inside the deposition chamber with liquid nitrogen. The frozen mixture then acts as the target for an incident pulsed laser beam. Using a pulsed laser, a small section of the frozen target will evaporate in a very short period of time, throwing the mixture into the vapor phase. The polymer material will then deposit on the substrate while the solvent will be pumped away (if you choose the correct solvent). This process has been used to successfully deposit a wide variety of polymer materials.

Lasers

The original MAPLE work utilized an excimer laser but IR lasers provide much better polymer thin film quality. The reason is the energy per photon for excimer lasers operates at 248-nm (KrF) in above 5 eV. This is enough energy to break polymer chains and reduce the functionality of the deposited polymer materials. PVD Products MAPLE systems utilize an Er:YAG laser that operates at 2.9 microns where each photon has only about 0.3 eV of energy. Thus, polymer functionality remains intact since the polymer chains are not fractured by the low energy photons.

Sample Injection

PVD Products MAPLE system utilizes a unique injection process that allows you to freeze your polymer/solvent mix in-situ after you have purged the chamber of water vapor. Our MAPLE system utilizes a quick target cool-down and quick target heat up assembly to maximize throughput. Our rotating target assembly makes excellent thermal contact with the cooling block.

Design

PVD’s MAPLE system is built around our popular Nano PLD chamber with large hinged front door for easy access to the internal components. This provides for easy sample transfers through the front door. The systems come complete with a fully enclosed optical train and laser beam rastering, turbo pumping package, and lap top computer control utilizing Lab View software. Valve packages can be manual or all electropneumatic as required. A wide variety of options standard are also available.

System Specifications

Maximum substrate size

One 2-inch diameter substrate or multiple small samples. Larger substrates and custom substrate holders are available on request.

Maximum substrate temperature

300°C typical, but other heaters are available.

MAPLE Target Temperature

-194°C (80 K)

Operating Pressure Range

Base pressure depends strongly on polymer/solvent mix and the solvent vapor pressure

MAPLE Target Size

Single 1.5” diameter target standard, larger targets available on request.

Target to Substrate (Throw) Distance

Variable from 2.5 to 4 inches

Raster path length

Across complete MAPLE target

Nominal Angle of Incidence

of the laser beam on target: 60°

Base Pressure of the Main Chamber

P < 5 x 10^-7 Torr guaranteed with system at room temperature and no polymer/solvent mix.

Vacuum Chamber

Box style chamber with easy substrate / target changes.

Operational Wavelength

2.9 microns (Er:YAG laser), other lasers/wavelengths available on request.

Please contact us for site prep information.