Industrial solution

Photovoltaics

From wafer intake through to module EL inspection.

Defect detection in cells and modules bears directly on yield. Conventional algorithms handle a single defect type well but generalise poorly to compound defects that vary in shape and scale. DSTEK detects them automatically in electroluminescence imagery, and supplies the wafer loading and unloading automation alongside.

Scope

What we inspect

Wafer intake

Size, saw marks, bow, breakage, micro-cracks and contamination; breakage, overlap and angle during basket insertion
Post-PECVD

Coating colour variation and surface defects — white spots, contamination, intra- and inter-cell colour difference, edge bow, etch marks
Screen printing

Grid breaks, print offset, line width, back-field delamination, paste leakage
PL / EL

Back-film contamination and suction marks, front-film scratches and white spots, post-print micro-cracks
Module EL

Linear and cross micro-cracks, black corners, black spots
Wafer handling

Loading and unloading automation; breakage, overlap and angle on basket insertion

Applications

Representative inspection tasks

A selection of what we have actually run on the line — not the full list. New inspection targets are approached the same way.

Mono/poly wafer inspection

Size, saw marks, bow, breakage, micro-cracks, contamination
Vertical basket inspection

Fragments, wrong wafers, overlapped or thick wafers, insertion imbalance (height difference over 20mm)
PECVD coating inspection

White spots, contamination, intra-cell and overall colour difference, edge bow, etch marks
SE electrode cell inspection

Two-dimensional reference deviation of ±15μm
Screen print inspection

Grid breaks, print offset, line width, back-field delamination, back-electrode offset, paste leakage
Cell colour sorting

Crystalline silicon colour depth and distribution, sorted into 8–24 trays
Junction box laser welding

Weld head guidance, busbar flatness inspection, post-weld quality inspection
Module string welding EL

Linear and cross micro-cracks, black corners and spots
Automatic wafer loading/unloading

Solar wafer loading and unloading line automation