Hangbo Alloy Group
Shanghai · Est. 2012
Semiconductor fabs use nickel alloys for wet benches, etching and cleaning with HF, sulfuric and nitric acids. See which grades fit ultra-high-purity service.
Modern semiconductor fabs move wafers through dozens of wet steps - RCA cleans, BOE oxide stripping, sulfuric-peroxide (SPM) attacks and metal lift-off - each exposing equipment to aggressive, ultra-high-purity (UPW) chemistries. A single metallic impurity in the parts-per-billion range can ruin a batch of 300 mm wafers. That is why wet benches, recirculation loops, spray manifolds and chemical-delivery components are built from corrosion-resistant nickel alloys rather than commodity stainless steel.
Unlike bulk chemical plants, a fab wet process tool has two conflicting requirements: the wetted surface must survive concentrated acids for years, yet it must not shed ions (Fe, Cr, Cu, Zn) into the process stream. Type 316L stainless passively resists many acids but its chromium oxide film is attacked by hydrofluoric acid and by fluoride-bearing mixtures, releasing iron and chromium that plate onto wafers as defects.
Nickel-molybdenum-chromium alloys such as Hastelloy C-276 and C-22 form an exceptionally stable, fluoride-resistant passive film and contain almost no free iron in the matrix. Their low carbon content avoids grain-boundary sensitization, so even a welded manifold keeps its corrosion resistance without post-weld heat treatment. For fabs this translates directly into fewer particle and metallic-contamination excursions and longer mean time between tool cleans.
The dominant wet chemistries each attack equipment differently. Hydrofluoric acid and buffered oxide etch (BOE) dissolve silica and strip the passive layer of ordinary stainless, so HF loops are almost always lined or built from nickel alloys qualified for HF service. Sulfuric-peroxide (SPM / piranha) runs hot, concentrated sulfuric that challenges even many nickel alloys, while nitric acid and sulfuric-nitric mixes are handled per the usual nitric acid selection rules and sulfuric acid selection rules.
Mixed or recycled chemistries are the hardest case: a reclaim loop may carry HF plus HCl plus dissolved metals, so grade choice should follow the most aggressive anion present, not the nominal bath. Detailed grade-by-grade resistance is summarized in our hydrochloric acid guide, which also applies to HCl-bearing etches.
For general HF and mixed-acid wet benches, Hastelloy C-276 remains the workhorse because of its broad reducing-acid resistance; its nominal composition is detailed in our C-276 composition reference. Where chloride and oxidizing conditions coexist (common in reclaim and cleaning loops), Hastelloy C-22 offers a wider safety margin, as shown in the C-22 corrosion-resistance overview.
For the most aggressive fluoride-oxide and mixed-oxidant services, higher-molybdenum grades such as Alloy 59 give the best pitting and crevice resistance. Our Alloy 59 corrosion-resistant note covers when the upgrade pays off. In practice, fabs standardize on one or two qualified alloys across a tool family to simplify cleaning validation and spare-parts management.
Choosing the right alloy is only half the battle. Surface condition matters as much as bulk chemistry: residual iron or copper from cutting, grinding or prior service can re-dissolve in UPW and contaminate wafers. We address this with dedicated, segregated finishing for electronics-grade material and verify cleanliness by Positive Material Identification and surface analysis, as described in our surface-contamination buyers guide.
Each heat is supplied with an EN 10204 3.1 certificate and, where required, additional elemental surface-scan data so the fab can qualify the part against its contamination budget. The result is a wetted path that is both chemically inert to the process chemistry and physically clean enough for sub-10 nm nodes.
For BOE and dilute HF etch loops, molybdenum-rich nickel alloys such as Hastelloy C-276 and C-22 are the standard because their passive film resists fluoride attack far better than 316L. The most aggressive fluoride-oxide mixes may justify Alloy 59; see our HF service guide for qualification details.
Not for HF or mixed-acid steps. 316L's chromium oxide film is stripped by hydrofluoric acid, releasing iron and chromium ions into the bath and onto wafers. Hastelloy C-276 or C-22 should be used wherever fluoride is present; our C-276 reference explains the chemistry difference.
We use segregated finishing, verify grade by PMI, and control surface iron/copper to the fab's budget, documented in our contamination guide. Every heat ships with EN 10204 3.1 certification so the wetted path meets ultra-high-purity requirements.
Wet benches and delivery systems use sheet, plate, welded manifolds, spray nozzles and small precision parts. Hangbo supplies these across standard forms with full ASTM/ASME documentation, complementing the corrosion data in our C-22 overview and Alloy 59 note.
As a dedicated nickel alloy manufacturer serving chemical processing sectors, Hangbo Alloy Group supplies the grades discussed here across all standard product forms with full ASTM/ASME documentation and EN 10204 3.1 certification. Our material is specified for applications where corrosion resistance, high-temperature strength, and traceable quality are non-negotiable. See our production & testing facilities for more on how every heat is verified.