Method and apparatus for monitoring optical characteristics of thin films in a deposition process

A sputter coating system comprising:

• a sputtering chamber having a coating station and a monitoring station;
• a sputtering target positioned within said chamber at said coating station;
• a disk having a generally planar surface positioned within said chamber and rotatable about an axis substantially perpendicular to said generally planar surface;
• an array of substrates carried by said disk on said generally planar surface past said coating station and said monitoring station, each substrate having an exposed surface to be coated;
• a source of an electromagnetic beam positioned at said monitoring station, said source being positioned so that said beam is incident on the exposed surface of a substrate passing by said monitoring station;
• one or more reflectors carried by said disk, each of said reflectors being positioned adjacent a different substrate on the side of the substrate remote from the exposed surface for reflecting a beam transmitted through the substrate back through the substrate;
• and
• a detector positioned at said monitoring station for measuring the beams reflected by said one or more reflectors.

An apparatus comprising:

• a chamber having a thin film coating station and an optical monitoring station;
• one or more sources of coating material positioned within said chamber at said coating station;
• a substrate mounting and moving means for carrying one or more substrates past said coating station and said optical monitoring station;
• one or more substrates mounted on said mounting and moving means;
• a source of an electromagnetic beam positioned at said optical monitoring station so that the electromagnetic beam provided by said source is incident on each substrate carried past said monitoring station;
• and
• a monitor positioned at said coating station for measuring a monitor beam, said monitor beam being the transmission of the incident beam through the substrate or the reflection of the incident beam from the substrate.

A method of optically monitoring selected optical characteristics of a coating on one or more substrates in a sputter deposition process, said method comprising the steps of:

• translating one or more of the substrates past a monitoring station;
• directing an electromagnetic beam through the coating formed on one or more of the substrates as the substrate passes the monitoring station;
• reflecting the beam transmitted through the coating and substrate back through the coating and substrate;
• measuring selected properties of the reflected beam;
• and
• determining selected optical characteristics of the coating.

A method of monitoring selected optical characteristics of a coating on one or more substrates comprising the steps of;

• directing an electromagnetic beam through the coating and substrate;
• retroreflecting the beam transmitted through the coating and substrate;
• and
• measuring selected optical characteristics of the retroreflected beam.

A method of monitoring selected optical properties of a coating formed on a substrate translating past a source of an electromagnetic beam wherein the angle of incidence of the beam on the coating changes during the translation, said method comprising the steps of:

• directing the beam through the coating as the substrate translates past the source;
• retroreflecting the beam transmitted through the coating;
• and
• measuring selected properties of the retroreflected beam.

A method of optically monitoring selected optical characteristics of a coating formed on one or more substrates comprising the steps of:

• directing an electromagnetic beam so that the beam is incident on the coating;
• measuring selected properties of the beam transmitted through the coating or reflected from the coating;
• determining selected optical characteristics of the coating;
• and
• retroreflecting the beam transmitted through the coating.