Edge Isolation

Edge Isolation

Single-sided edge isolation for maximum efficiency

The Edge Isolation + PSG Etching Inline System fully automatically achieves a perfect edge isolation. The transport system developed by SCHMID especially for edge isolation ensures low chemistry consumption. In combination with the patented water mask the emitter is optimally isolated.

Product benefits

Minimum drag-out

Patented water mask

Stable process without cooling unit

Shortest maintenance times due to good accessibility and easy cleaning

Special cleaning processes for PERC-cells available

Can be combined with selective emitter technology


The Edge Isolation + PSG Etching Inline System combines several process steps in one system with modular design. On the one hand the emitter layer on the rearside of the wafer generated during the diffusion process is unilaterally isolated from the front side of the wafer in order to prevent malfunction of the solar cell. On the other hand the phosphorous silicate glass (PSG) is removed from the wafer surface.

During the edge isolation the emitter is protected by the water mask developed and patented by SCHMID. Special profiled transport rollers ensure that the chemistry comes into contact exclusively with the rearside, and therefore little chemistry is consumed.

For the etching of the phosphorus silicate glass special holding-down shafts are used instead of shafts fitted with O-rings. These do not leave impressions on the wafers. In addition, the modified conveyor allows easy cleaning of the shafts. Therefore, organic pollution of the wafers by the transport system is excluded.

The rinsing between the individual process steps ensures minimum drag-out. SCHMID’s multiple cascade technology reduces the consumption of DI water. Thanks to the modular design of the inline system, throughput and process steps can be adapted to customers’ needs. In addition, special cleaning processes are available for common cell concepts.

Technical Data

Throughput (M12):

  • 5,000 wafers/h (5 tracks)
  • 10,000 wafers/h (10 tracks)
  • Further throughputs configurable

Wafer size:

  • M2 – M12

Breakage rate:

  • < 0,1 %

Process media:

  • HF
  • KOH
  • HNO3


  • Optional Loader and Unloader

Other equipments for photovoltaics & glass


Surface finishing for glass
The AGTex offers innovative methods for processing and finishing glass surfaces. The technology is particularly suitable for the production of antireflection and antiglare coatings on glass.

Alkaline Texturing

Efficient texturing of mono-crystalline wafers
The Alkaline Texturing Inline System of SCHMID ensures the most efficient texturing of mono-crystalline wafers.

APCVD System

Low cost inline deposition of thin films
The 5500 series APCVD system is well suited for low cost high-volume processing for all cell architectures requiring single or multi-layer dielectric thin film deposition.

Poly Silicon & BSG Etching

Poly Silicon & BSG Etch for TOPCon Manufacturing
The Alkaline Poly–Si and BSG Etching Inline System achieves a perfect cleaning of the sunny side for n- and p-doped polysilicon and Boroan glass removal.

Alkaline Polishing for PRTC and TOPCon

NOX-free edge isolation and polishing
The Alkaline Edge Isolation Inline System achieves a perfect edge isolation with an alkaline solution.


We look forward to meeting you!

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Tracy Xie


Johnny Tseng


Jaho Kim