Solar panel manufacturing begins with processes that transform semiconductor materials into electricity-generating cells. During silicon solar-cell production, wafers undergo cleaning, surface texturing, selective etching and rinsing. Each operation depends on controlled delivery of chemicals or high-purity water.
Flexible PTFE tubes and PFA tubes can provide the fluid connections serving these operations. Their value lies in combining chemical resistance with properties suited to the equipment's temperature, cleanliness and installation requirements.
These applications primarily concern solar-cell manufacturing equipment, rather than tubing incorporated into the finished photovoltaic panel.
Where Are Flexible PTFE and PFA Tubes Used?
1. Chemical Supply and Precision Dosing
Wet-processing equipment requires measured quantities of acids, alkalis, additives and dilution water. Suitable fluoropolymer tubing can connect chemical containers, dosing pumps, filters, valves and processing chambers.
The tube must tolerate the concentrated supply chemical, the working solution and any flushing liquid. High-purity PFA is particularly relevant when contamination limits are stringent. PTFE is another candidate where its documented cleanliness and mechanical performance meet the specification.
Tubing dimensions also matter: an undersized bore can restrict delivery, while unnecessary internal volume can delay changes in chemical concentration.
2. Wafer Cleaning Before Further Processing
Residues, particles and metallic impurities must be controlled before sensitive manufacturing stages. Depending on the production route, cleaning may involve ammonium hydroxide, hydrogen peroxide, hydrochloric acid and hydrofluoric-acid treatments.
Compatible PTFE or PFA tubing supplies individual ingredients or prepared solutions to the cleaning tool. For heated mixtures, both chemical resistance and pressure capability at operating temperature require verification.
Clean tubing helps preserve process-liquid quality, but fittings, valves and installation practices must meet the same cleanliness requirements.
3. Silicon Surface Texturing
Texturing produces microscopic surface features that reduce reflection and help the cell capture incident light.
Monocrystalline-silicon processes commonly employ potassium-hydroxide- or sodium-hydroxide-based solutions with appropriate additives. Acidic mixtures containing hydrofluoric and nitric acids have also been used for multicrystalline silicon.
Qualified tubing can serve the chemical-feed, bath-replenishment and sampling circuits. Its suitability depends on the complete recipe, including additives, temperature and exposure duration.
Where organic solvents are present, the assessment should also consider permeation and electrostatic conditions.
4. Oxide and Diffusion-Glass Removal
Some diffusion processes leave dopant-containing glass on the silicon surface. Examples include phosphosilicate glass following phosphorus diffusion and borosilicate glass associated with boron diffusion.
HF-based wet treatments commonly remove these layers. Suitable PTFE or PFA tubes may supply acid, dilution water or prepared etchant to the treatment equipment.
For this duty, a chemically resistant tube must also provide acceptable cleanliness, permeation performance and connection integrity.
Flexible fluoropolymer delivery tubing should not be confused with the furnace tube used during high-temperature diffusion.
5. Selective Etching, Isolation and Polishing
Different cell architectures require different material-removal steps. These can include edge isolation, rear-surface polishing and removal of unwanted deposited layers in TOPCon-related processing.
Depending on the equipment, acidic solutions or heated alkaline chemistry perform these operations. Compatible tubing supplies fresh chemicals and replenishment liquids to the relevant processing stage.
Approval for one etchant does not establish suitability for another. Each circuit needs assessment against its actual operating conditions.
6. Rinse-Water Delivery and Process Sampling
Rinsing removes residual chemicals between manufacturing stages. High-purity PFA can be considered for point-of-use deionised or ultrapure-water connections where its documented cleanliness meets the requirement.
PTFE or PFA sample lines can also transport bath liquids to analytical instruments. Appropriate bore and short routing help reduce sample delay and retained liquid.
Which Tubing Properties Are Important?
Broad Chemical Resistance
PTFE and PFA resist many corrosive chemicals, making them useful candidates for photovoltaic wet processing. Selection must nevertheless address the actual mixture, concentration, temperature and exposure time. Seals and fittings require separate compatibility checks.
Low Extractables and Cleanliness
A tube should not introduce unacceptable impurities into the liquid it carries. Resin selection, manufacturing controls, cleaning and packaging all influence this performance.
Temperature and Pressure Performance
Some PTFE and PFA tubing products have published temperature capabilities approaching 260°C. This does not mean they retain their room-temperature pressure rating at elevated temperatures.
Allowable working pressure depends on the product, diameter, wall thickness, temperature and connections.
Flexibility and Installation
Flexible tubing assists routing within compact equipment. However, tight bends, twisting and inadequate support can impair performance. Continuous movement requires specific qualification.
Natural PFA generally offers better visibility of the liquid path than PTFE. Suitable PFA products may also support qualified fusion connections.
Selecting Tubing for Your Production Line
High-purity PFA is often a suitable starting point for contamination-sensitive duties. PTFE remains a practical option where verified purity, compatibility and connection performance satisfy the process.
Prepare your chemical composition, operating conditions, dimensions and cleanliness requirements before selecting either material. Discuss your application with Advanced Fluro — call us on +91 96990 55600.
Discuss Your Requirements with Advanced Fluro
Explore flexible PTFE tubing and PFA tubing from Advanced Fluro.
Have a drawing or process specification available? Email contact@aftubes.com with the details, or share your requirements to discuss tubing options for your photovoltaic manufacturing equipment.
Article by
Savio Pereira
Savio Pereira is a Chemical Engineer who has held leadership roles in companies like IBM. A passionate problem solver who thrives at finding solutions to engineering and business problems alike using simple innovative ideas. He believes in doing things differently rather than doing different things. His vision is to make Advanced Fluro (P) Ltd the most valuable company in the fluouro polymer industry.