Method of coating a coating region on a front surface of a substrate and apparatus for a thermal evaporation system

Method of coating a coating region on a front surface of a substrate with a source material, the method comprising the following steps:

• a) Providing the substrate with a substrate material transparent or at least essentially transparent to the electromagnetic radiation,
• b) Arranging the substrate and a source within a reaction chamber to dispose the substrate between the chamber window and the source, whereby the source comprises one or more source sections consisting of the source material, and whereby the reaction chamber contains a reaction atmosphere, and the front surface of the substrate faces the source and a back surface of the substrate faces the chamber window,
• c) Illuminating the source with electromagnetic radiation provided as one or more incident radiation beams coupled into the reaction chamber through the chamber window of the reaction chamber and through the substrate during the coating process for thermally evaporating and/or sublimating source material from the source and depositing it onto the substrate;
• wherein the one or more incident radiation beams and a normal to the surface of the source include an incident angle larger than 0° and smaller than 90° and thereby form a radiation plane;
• wherein the substrate is subdivided into two or more substrate segments, whereby the two substrate segments are arranged back to back connected by a substrate connector, and moved together during the coating process,
• wherein the substrate connector is less transparent than the substrate material of the adjacent substrate segements with respect to the electro magnetic radiation, and in step c) an intensity of the one or more incident radiation beams is increased during an illumination of the substrate connector by parts of the one or more incident radiation beams, or
• wherein the substrate connector is more transparent than the substrate material of the adjacent substrate segments with respect to the electromagnetic radiation, and in step c) an intensity of the one or more incident radiation beams is reduced during an illumination of the substrate connector by parts of the one or more incident radiation beams, or
• wherein the substrate connector is less transparent than the substrate material of the adjacent substrate segments with respect to the electromagnetic radiation, and the velocity of the movement of the substrate is reduced during an illumination of the substrate connector by parts of the one or more incident radiation beams, or
• wherein the substrate connector is more transparent than the substrate material of the adjacent substrate segments with respect to the electromagnetic radiation, and the velocity of the movement of the substrate is increased during an illumination of the substrate connector by parts of the one or more incident radiation beams.