Laser scribing of thin-film solar cell panel

A laser scribing process for the manufacture of a thin-film solar panel, the process comprising:

• loading a planar workpiece with a transparent substrate facing downwards in an input station of a laser scribing machine;
• biasing a reference edge of the planar workpiece to contact both a fixed stopper and an adjustable stopper associated with a linear drive, wherein the linear drive is operated to translate the planar workpiece between the input station and an output station;
• determining amounts of deviations of the reference edge or a reference line at the reference edge from the linear drive from a front end to a rear end of the planar workpiece, and adjusting the adjustable stopper accordingly by rotating the planar workpiece in a flat plane spanning the planar workpiece so as to correct parallelism of the reference edge or reference line with the linear drive;
• translating the planar workpiece back and forth between the input station and the output station and firing a laser beam at a first frequency vertically through a space between the input and output stations to pass through the transparent substrate of the planar workpiece to scribe parallel lines (LP1) on a front electrode layer, which is disposed on an upper face of the transparent substrate, wherein the laser beam is outputted from a laser source that is mounted on an independently motorized axis disposed transverse to the linear drive;
• and
• indexing the laser source at a predetermined pitch transversely to the linear drive and repeating the back and forth translation of the planar workpiece between the input and output stations until the entire front electrode layer is divided into parallel strips of a uniform width that are electrically isolated one from another;
• providing a number of laser sources and dividing an area of laser scribing on the planar workpiece into a number of gangs according to the number of laser sources, and conducting laser scribing on the planar workpiece simultaneously in the respective gangs;
• the method further comprising:
• reloading the planar workpiece formed with parallel, uniform strips of the front electrode layer and disposed with a new semiconductor layer or a rear electrode layer in the input station;
• biasing the reference edge of the planar workpiece to contact both the fixed stopper and the adjustable stopper;
• aligning a scribed line (Lp1) on the front electrode layer with the linear drive by using a measuring camera (C1-C4) disposed above the planar workpiece and another measuring camera (C5) disposed near the adjustable stopper to determine a correction required to align parallelism between the scribed line (Lp1) with the linear drive, adjusting the adjustable stopper accordingly by rotating the planar workpiece in the flat plane to achieve the required parallelism, and adjusting position of each of the laser sources, when necessary, to achieve scribing strips of a uniform width;
• translating the workpiece back and forth between the input station and output station and firing laser beams at a second frequency vertically through the space between the input and output stations to pass through the transparent substrate of the planar workpiece to scribe parallel lines (Lp2, Lp3) on the semiconductor layer or rear electrode layer parallel to the previously scribed lines (Lp1 or Lp2);
• and
• indexing the laser sources, and repeating the back and forth translation of the planar workpiece between the input and output stations until the entire semiconductor layer or rear electrode layer is divided into parallel strips of a uniform width that are electrically isolated one from another.