1. Comparison of Core Parameters for the Three Materials

PFA, PTFE and PVDF are the mainstream fluoroplastics for semiconductor wet processes. Their key characteristics are summarized below: ✅ Temperature Resistance

PFA: Max continuous service temperature 260°C; the commonly used upper limit for wet processes is 180°C

PTFE: Max continuous service temperature 260°C; susceptible to creep (cold flow), resulting in poor dimensional stability under pressure

PVDF: Max continuous service temperature 120°C, short-term peak up to 150°C; poorest high-temperature performance among the three

✅ Chemical Resistance

PFA: Same fluoropolymer family as PTFE with broad chemical resistance; only a few high-temperature solvents cause swelling

PTFE: Widest chemical resistance of the three; only attacked by very few media such as molten alkali metals and elemental fluorine

PVDF: Good resistance to common acids and bases; not resistant to strong alkalis, amines and strong polar solvents

✅ Welding & Jointing

PFA: Hot butt welding, flaring and flange connections available; well-established piping connection solutions

PTFE: Not melt-processable and non-weldable; mainly used for linings and static components

PVDF: Socket fusion, hot welding and flange connections available; convenient for on-site installation

✅ Purity, Permeability & Cost

Leachables: Ultra-high-purity PFA and PTFE show extremely low metal leaching; high-purity PVDF grade is available with slightly higher leaching level

Permeability: Low permeability for PFA and PTFE; relatively higher permeability for PVDF

Cost: PFA and PTFE are high-cost materials; PVDF is medium-priced with obvious cost-performance advantages

✅ Common Product Forms

PFA: Tubes, fittings, valves, pumps and other fluid components

PTFE: Wafer carriers, gaskets, linings, bellows

PVDF: Standard piping & valves, tank bodies, exhaust ducts

2 Material Selection by Operating Condition

👉 High-temperature acid bath (≥100°C) & high-temperature strong oxidizing chemicals 

First choice: PFA｜Alternative: PTFE static components 

⚠️ PVDF is prohibited for this condition

👉 Ambient-temperature acid & alkali piping network 

First choice: PFA｜Alternative: PVDF 

💡 Select PVDF for cost control when purity requirement is moderate; use PFA for ultra-high-purity requirements

👉 Fluid system containing strong alkalis or amines 

First choice: PTFE｜Alternative: PFA 

⚠️ PVDF shall be avoided

👉 Point-of-use ultra-high-purity chemical supply 

First choice: Ultra-high-purity PFA｜Alternative: Ultra-high-purity PVDF 

💡 Particle and metal leaching criteria shall comply with project specification

👉 Large-bore piping, tank & equipment connections 

First choice: PVDF / PFA flange｜Matching: PTFE gaskets 

💡 Gasket material shall be re-verified against process media

👉 Static sealing gaskets 

First choice: Encapsulated PTFE gaskets｜Alternative: FFKM 

💡 Dynamic sealing cannot follow this rule; separate evaluation by medium is required