Process Chain

The process chain shows the process steps and is an example of the aSi/µSi and CdTe technology in substrate buildup (CIGS is built in reverse order, i.e. in substrate configuration).

Front contact coating: a transparent and conductive front contact coating is applied to a glass substrate.

Laser scribing P1

The laser scriber structures this coating (355 nm or 1064 nm wavelength, depending on the front contact material) through the glass.

Absorber coating: A semi-conductor is applied to the front contact coated substrate.

Laser scribing P2

The Laser Scriber selectively ablates the semiconductor using a green wavelength (532 nm wavelength) through the glass and front contact.

Coating: the back contact is applied. A conductive connection is created between the front- and back contact in the P2 channel.

Laser scribing P3

The Laser Scriber selectively structures the semiconductor and the rear contact (532 nm wavelength) through the glass and the front contact. Within the front- and back contact the adjacent cells are now electrically isolated and connected in series via the contact between front- and rear contact in the P2 channel.

Edge deletion: by laser ensures the modules are safely isolated towards its edges and prepares the module for encapsulation.

Extremely high temperatures are used for the absorber coating, especially with CdTe and CIGS technology, resulting in significant thermal distortion in large substrates. To ensure high module performance it is crucial for the Laser Scribers to detect the resulting warped P1 or P2 lines and curved substrates, and to be able to compensate for this during subsequent structuring. LPKF SolarQuipment Allegro Laser Scribers feature mechanisms to automatically compensate such distortion, thus ensuring high module performance.