Silicon oxide coated polymer films and low pressure PECVD methods for producing the same

A process for producing a silicon oxide layer on a moving polymer substrate which is amorphous and homogeneous throughout the layer thickness, comprising:

• providing the moving polymer substrate,
• providing a PECVD device in a vacuum chamber maintained at a pressure between 0.005 and 0.025 Torr comprising at least one linear hollow-cathode plasma source, each source comprising at least one pair of electrodes connected to an AC, DC or pulsed DC generator, for the deposition of said layer on the substrate,
• applying an electrical power to the at least one linear hollow-cathode plasma source, so that a power density of the plasma is between 1 kW and 30 kW per linear meter of at least one linear hollow-cathode plasma source, wherein the low-pressure PECVD device is in a vacuum chamber maintained at a pressure between 0.005 and 0.025 Torr, and wherein a ratio of a power per linear meter of the at least one linear hollow-cathode plasma source to the pressure in the vacuum chamber, is not less than 0.2 (kW/m)/mTorr and not greater than 1.5 (kW/m)/mTorr, and
• applying, to the moving polymer substrate, a gaseous precursor of oxides of silicon at a flow rate of between 50 and 700 sccm per linear meter of the at least one linear hollow-cathode plasma source, and a reactive gas based on oxygen or on oxygen-comprising derivatives at a flow rate of between 1500 and 4000 sccm per linear meter of the at least one linear hollow-cathode plasma source,
• wherein the applying the gaseous precursor of oxides of silicon takes place while the polymer substrate is moving between an unwind roll and a main roll,
• wherein the gaseous precursor of oxides of silicon being injected in between the electrodes of each electrode pair and in between the at least one of the two pairs of electrodes and the reactive gas being injected in the electrodes of the at least one linear hollow cathode plasma source,
• wherein the silicon oxide layer on the polymer substrate is deposited with a dynamic deposition rate of at least 200 nm×m/min,
• wherein a substrate temperature remains below 37° C. during the process, and
• wherein the silicon oxide layer has a thickness of from 90 nm to 685 nm and a transmittance (D65/2°) of at least 88%.

A process for the production of a layer based on silicon oxide on a polymer substrate which is amorphous and homogeneous throughout the layer thickness, comprising:

• providing the polymer substrate,
• providing a low-pressure PECVD device comprising at least one linear hollow-cathode plasma source, each source comprising at least one pair of electrodes connected to an AC, DC or pulsed DC generator, for the deposition of said layer on the substrate,
• applying an electrical power to the at least one linear hollow-cathode plasma source, so that a power density of the plasma is between 1 kW and 50 kW per linear meter of the at least one liner hollow-cathode plasma source,
• wherein the low-pressure PECVD device is in a vacuum chamber maintained at a pressure between 0.005 and 0.025 Torr, and wherein a ratio of a power per linear meter of the at least one linear hollow-cathode plasma source to the pressure in the vacuum chamber, is not less than 0.2 (kW/m)/mTorr and not greater than 1.5 (kW/m)/mTorr, and applying, to the polymer substrate, a gaseous precursor of oxides of silicon at a flow rate of between 50 and 700 sccm per linear meter of the at least one linear hollow-cathode plasma source, and a reactive gas based on oxygen or on oxygen-comprising derivatives at a flow rate of between 1500 and 4000 sccm per linear meter of the at least one linear hollow-cathode plasma source,
• wherein the gaseous precursor of oxides of silicon being injected in between the electrodes of each electrode pair and in between the at least one of the two pairs of electrodes and the reactive gas being injected in the electrodes of the at least one linear hollow-cathode plasma source,
• wherein the polymer substrate is maintained at a temperature of 60° C. or less, and
• wherein the layer based on silicon oxide has a thickness of from 90 nm to 685 nm and a transmittance (D65/2°) of at least 88%.