Electronic Grade chemicals

What electronic grade means

Electronic grade, also called semiconductor grade, describes chemicals purified for the manufacture of semiconductors, displays, photovoltaics and printed circuit boards. Metal contaminants at parts-per-billion levels can alter the electrical properties of silicon, and particles can cause defects in fine circuit features. The grade therefore specifies individual trace metals, anions and particle counts at levels far below those of reagent grades, and requires cleanroom-compatible packaging.

Many products are specified against SEMI standards, published by the industry association SEMI, which define tiers of purity for process chemicals. Higher tiers carry lower limits, down to parts-per-trillion for the most critical applications. Names such as VLSI, ULSI or CMOS grade are used by some manufacturers for their own tiers.

Typical specification profile

Values in the table are typical of the grade. The limits that apply to a given product are those stated on its specification and lot Certificate of Analysis.

Where it is used

• Wafer cleaning (for example, SC-1 and SC-2 cleans using ammonia, peroxide and hydrochloric acid)
• Wet etching with hydrofluoric, nitric, phosphoric and buffered oxide etchants
• Photoresist stripping and development with solvents and tetramethylammonium hydroxide
• Trace metal analysis by ICP-MS, where blank levels must be minimal

How it differs from neighbouring grades

AR and ACS grades limit metals at ppm levels, around three orders of magnitude higher than electronic grades. Trace-metal analysis grades for ICP-MS approach electronic-grade metal limits but may not specify particles. Technical grade products are unsuitable. Packaging is part of the grade: electronic chemicals are filled into pre-cleaned, fluoropolymer or high-purity polyethylene containers, often in cleanroom conditions, and quality can be lost if decanted into ordinary bottles.

Sourcing

Electronic-grade supply is highly application-specific. Send us the SEMI grade or the full list of metal, anion and particle limits you require, and we will confirm what can be met and in which packaging.