▼ Industry Background
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PV cell manufacturing relies heavily on wet chemical processes. From the initial silicon wafer texturing to the final RCA cleaning before delivery, six core procedures all demand precise delivery, proportioning and circulation of chemical liquids. Though PERC, TOPCon and HJT differ slightly in process parameters, they share identical core requirements: reliable transfer of highly corrosive media (KOH, HF, HNO₃, HCl, H₂O₂), accurate metering of trace dopants, pulsation-free feeding of high-viscosity pastes, and contamination-free circulation of ultra-pure cleaning solutions.

Equipped with fully inert PEEK + zirconia ceramic wetted channels, ±0.2% repeat accuracy and leak-free magnetic drive design, JONSN MR Series magnetic gear pumps form a unified wet-process fluid platform applicable to PERC, TOPCon and HJT technologies.

▼ Industry Pain Points
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▎Full-spectrum strong acid, alkali and oxidizer corrosion shortens pump service life

Texturing uses hot mixed KOH/H₂O₂ solution (70–85°C); etching involves HF/HNO₃ mixed acids; RCA cleaning alternately applies SC1 (NH₄OH/H₂O₂) and SC2 (HCl/H₂O₂), plus dilute DHF. These chemicals corrode nearly all metallic pump bodies and standard seals. Traditional mechanically sealed pumps often fail within 3 months under alternating hot alkali and HF exposure. Leakage contaminates cleanrooms and poses severe safety risks of HF chemical burns.

▎Trace metering deviation of dopants causes wasted wafers

The dosage of liquid POCl₃ source (phosphorus diffusion for PERC/TOPCon) and boron precursors (boron diffusion for TOPCon/HJT) directly determines sheet resistance uniformity of PN junctions. A flow deviation exceeding ±1% leads to sheet resistance fluctuation, reducing cell conversion efficiency by 0.1%~0.3%. Conventional bubbler systems and mass flow meters lack stable trace liquid control, resulting in inconsistent batch-to-batch process performance.

▎High-viscosity screen printing paste dries easily; feeding fluctuations cause broken grid lines

Silver paste viscosity reaches tens of thousands mPa·s, requiring constant pressure and pulsation-free flow during screen printing. Feeding pressure fluctuation over ±5% triggers broken grids or uneven finger width, directly lowering fill factor (FF) and complicating module power sorting. Silver paste contains precious metals, so residual material inside pumps translates to substantial material loss.

▎Zero metal leaching is mandatory for ultra-pure cleaning fluids

RCA cleaning before anti-reflection coating deposition is extremely sensitive to metallic contaminants (Fe, Cu, Ni) on silicon wafer surfaces, with impurity concentrations limited to ppb levels. Wetted parts containing stainless steel or copper alloys release trace metal ions, damaging passivation layers and degrading cell efficiency. Fully inert flow paths with PEEK and perfluoroelastomer seals are essential for the process.

▼ JONSN Solutions for Six Full-Line Processes
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▎Step 1: Texturing

Proportion accuracy of hot KOH/H₂O₂ mixture (70–85°C) governs uniform pyramid texture size. JONSN MRA Series (100–2000 ml/min) delivers continuous proportional supply of KOH and H₂O₂, while MPG Series (1–280 ml/min) performs micro-injection of texturing additives (isopropanol/texturing agents). PEEK pump heads and zirconia ceramic gears resist corrosion and ion leaching under long-term operation at 85°C hot alkali. ±0.2% repeat accuracy ensures consistent bath solution ratios across batches, stabilizing surface reflectance within process windows.

• Recommended: MPG Series (micro additive injection) + MRA Series (KOH/H₂O₂ proportioning)

▎Step 2: Diffusion Doping

Precise delivery of liquid POCl₃ (phosphorus diffusion for PERC/TOPCon) and trimethyl borate / boron tribromide (boron diffusion for TOPCon/HJT) is critical to sheet resistance uniformity. The JONSN MPG Series (40 μl/r displacement, minimum flow 1 ml/min) paired with closed-loop stepper motor drive achieves ±0.2% dopant flow accuracy, ensuring full-wafer sheet resistance uniformity ≤ ±2 Ω/□. Full magnetic sealing eliminates leakage of POCl₃, which reacts with water to form corrosive HCl, fully protecting diffusion furnace operational safety.

• Recommended: MPG Series (1–280 ml/min, 40 μl/r displacement)

▎Step 3: Wet Etching

Wet etching uses HF/HNO₃ mixed acids to remove phosphosilicate glass (PSG) or borosilicate glass (BSG) and polish wafer backsides. Circulation and replenishment pumps must withstand HF corrosion, HNO₃ oxidation and heat released by acid reactions. JONSN MRA/MRB Series offer optional Hastelloy C-276 pump heads with PTFE seals, or all-PEEK flow paths to completely eliminate metal ion leaching. Flow rates of 100–4800 ml/min support single-tank and multi-tank parallel layouts.

• Recommended: MRA Series (100–2000 ml/min) + MRB Series (400–4800 ml/min)

▎Step 4: Anti-Reflection Coating (PECVD Precursor Supply)

Liquid precursors such as TEOS and TMA for SiNx anti-reflection film deposition require bubble-free, pulsation-free delivery to PECVD chambers. Bubbles entering vaporizers cause uneven film thickness and pinhole defects. The positive displacement volumetric design of JONSN MPG Series delivers natural pulsation-free flow. Fully inert PEEK flow paths resist swelling and adsorption of organosilicon/organoaluminum precursors like TEOS and TMA. Ultra-low dead volume (<0.5 ml) guarantees consistent precursor delivery volume for every batch.

• Recommended: MPG Series (1–280 ml/min, dead volume < 0.5 ml)

▎Step 5: Screen Printing Paste Feeding

Front silver paste, back silver and back aluminum pastes feature high viscosity ranging from 10,000–50,000 mPa·s. Any feeding pressure fluctuation directly distorts finger width. The JONSN DP Series high-precision gear metering pumps (0.2–100 cc/r) are engineered for high-viscosity media: multi-tooth gear sets and precision chambers adopt positive displacement design to stabilize silver paste flow independent of backpressure. Optional DLC-coated gears enhance wear resistance against glass powder in silver paste. Ultra-low dead volume minimizes residual paste during color changeovers, cutting costly silver material waste.

• Recommended: DP Series (0.2–100 cc/r, optional DLC coating)

▎Step 6: RCA Cleaning

Standard RCA cleaning cycles alternate SC1 (NH₄OH + H₂O₂ + H₂O, 75–80°C) for organic and particle removal, SC2 (HCl + H₂O₂ + H₂O, 75–80°C) for metallic ion removal, and DHF for native oxide stripping. Three core requirements apply: fully inert flow paths with ppb-level zero metal leaching, seal stability under strong oxidizing H₂O₂ environments, and thorough dead-volume flushing to avoid cross-contamination between three chemical liquids.

JONSN MPG Series adopts PEEK pump heads, zirconia ceramic gears and perfluoroelastomer O-rings with zero metallic contact across all wetted surfaces. Fast flushing enables seamless switching between SC1, SC2 and DHF; dead volume <0.5 ml eliminates cross-contamination. Flow rates of 1–280 ml/min suit R&D pilot lines up to GW-scale mass production cleaning supply systems.

• Recommended: MPG Series (1–280 ml/min, all-PEEK flow path, ppb-level zero metal leaching)

▼ One Product Matrix for Three PV Technical Routes
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▼ Core Advantages
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▎Single pump platform for full production lines

Four product lines (MPG/MRA/MRB/DP) cover all fluid handling demands across six processes from texturing to RCA cleaning. PV equipment manufacturers only cooperate with one pump supplier for model selection, spare parts and after-sales support.

▎Fully inert flow paths withstand all corrosive chemistries

PEEK + zirconia ceramic + perfluoroelastomer seals create metal-free wetted surfaces. The pumps fully resist KOH, HF, HNO₃, HCl, H₂O₂ and all other process chemicals used in cell manufacturing.

▎ppb-level zero metal leaching to sustain conversion efficiency

No Fe/Cu/Ni metallic ions are introduced during ultra-pure processes including RCA cleaning and precursor delivery, preserving passivation layer quality and cell efficiency. Compliant with mass production process windows: PERC ≥23.5%, TOPCon ≥25%, HJT ≥25.5%.

▎±0.2% dopant accuracy for consistent batch sheet resistance

POCl₃/boron precursor injection accuracy reaches ±0.2%, delivering full-wafer sheet resistance uniformity ≤ ±2 Ω/□. Reproducible process parameters across batches, production lines and equipment stabilize mass production yield.

▎Pulsation-free silver paste feeding eliminates broken grid lines

Positive displacement design of DP Series limits screen printing feeding pressure fluctuation below ±2%. Broken grid rates drop significantly with uniform finger width, enabling precise closed-loop control of fill factor (FF). Silver paste residual volume inside dead cavities reduces by over 60% versus conventional pumps.

▎Long maintenance-free service life matching GW-scale continuous lines

Zirconia ceramic gears and PEEK bearings deliver verified 20,000 hours maintenance-free operation. PV production lines run 7×24 without pump shutdowns, greatly lifting Overall Equipment Efficiency (OEE).