Cleaning Chemicals

Contamination control sits at the very foundation of semiconductor manufacturing. As device features shrink into the sub-nanometer realm, even trace amounts of organic residue, metallic ions, or particulate matter can devastate electrical performance and cripple production yields. Cleaning operations, therefore, represent far more than routine maintenance: they constitute a decisive set of process steps that determine whether a wafer proceeds toward functional chips or becomes scrap.

The chemicals used in these cleaning operations must satisfy extraordinarily demanding specifications. Metallic impurities are controlled at parts-per-trillion levels. Particle counts are minimized through advanced filtration. Organic residue is essentially eliminated. At Eata Electronic, we supply a comprehensive range of cleaning chemicals engineered for these exacting requirements, spanning from standard wet bench formulations to highly specialized blends targeting specific contamination profiles encountered in research and industrial environments.

Figure 1: Multi-tank ultrasonic wafer cleaning station in a controlled cleanroom environment

RCA Standard Clean Formulations

Developed at RCA Corporation in the 1960s and subsequently refined over decades of semiconductor production, the RCA clean process remains the benchmark for comprehensive wafer surface preparation. The procedure relies on two sequential chemical treatments, each targeting distinct classes of contaminants, with intermediate rinsing steps to prevent cross-contamination.

Standard Clean 1: APM Solution

The SC-1 step, also known as the Ammonium Peroxide Mixture, combines ammonium hydroxide, hydrogen peroxide, and deionized water to remove organic films, particles, and certain light metallic contaminants. The alkaline environment created by ammonium hydroxide slightly etches the silicon surface, loosening particulate adhesion through zeta potential modification. Meanwhile, hydrogen peroxide continuously regenerates a thin oxide layer, preventing excessive substrate loss while lifting organic residues through oxidative decomposition. Typical operating conditions involve temperatures of 75 to 80 degrees Celsius with immersion times of 10 to 15 minutes. We supply ammonium hydroxide and hydrogen peroxide at electronic-grade purity levels suitable for SC-1 formulation, with full trace metal certification accompanying every lot.

Standard Clean 2: HPM Solution

Following SC-1 and thorough deionized water rinsing, the SC-2 step, or Hydrochloric Peroxide Mixture, targets metallic ionic contaminants that the alkaline SC-1 cannot effectively address. The acidic, oxidizing environment dissolves metal traces including alkali ions, transition metals, and aluminum while leaving the silicon oxide surface intact. The resulting passivation layer protects the wafer from recontamination during subsequent handling. Like SC-1, SC-2 typically operates at elevated temperature for 10 minutes. Our hydrochloric acid and hydrogen peroxide products carry the same electronic-grade certification, ensuring that the cleaning chemicals themselves do not introduce new contamination.

Figure 2: A silicon wafer undergoing Marangoni vapor drying after wet chemical cleaning

Specialized Cleaning and Stripping Chemistries

Piranha and Sulfuric Peroxide Mixtures

For situations demanding aggressive organic removal, Piranha solution, a mixture of concentrated sulfuric acid and hydrogen peroxide, delivers unmatched oxidative power. This chemistry effectively strips photoresist, removes organic residues that standard SC-1 cannot touch, and hydroxylates surfaces to render them hydrophilic. The heat generated during mixing and the highly exothermic reaction with organic matter require careful handling in quartz vessels with appropriate safety measures. Common ratios range from 3:1 to 7:1 sulfuric acid to hydrogen peroxide depending on the application severity. We provide both components at the elevated purity grades necessary for this demanding chemistry.

Photoresist Stripping Solvents

After patterning operations, complete photoresist removal is essential before further processing. Organic solvent strippers including N-Methyl-2-pyrrolidone and dimethyl sulfoxide dissolve resist films through polymer chain disruption, even for resists that have undergone significant cross-linking during plasma processing. For less demanding applications, acetone provides rapid, economical stripping of uncured or lightly exposed resists. Isopropyl alcohol serves as an excellent rinse agent following any solvent-based strip step, displacing dissolved organics and preparing the surface for aqueous processing. Each of these solvents is available from our portfolio in technical through electronic-grade specifications.

Post-Etch Residue Removers

Plasma etching, while essential for fine pattern transfer, frequently leaves behind complex residues comprising polymerized photoresist fragments, metal halides, and oxide debris. These post-etch residues cannot be removed by standard RCA cleaning and require specially formulated removers. Hydroxylamine-based chemistries offer broad compatibility with copper and low-k dielectric materials. Fluoride-containing organic formulations address more stubborn oxide-metal residue complexes. Each product is engineered for high selectivity, attacking residues while preserving the underlying films and structures that constitute the functional device.

Figure 3: Silicon wafers being transferred between cleaning solution baths during wet processing

Electronic-Grade Cleaning Solvents

Beyond the reactive chemistries of RCA and Piranha processes, semiconductor manufacturing consumes substantial quantities of high-purity solvents for rinsing, drying, and general surface preparation. The selection of appropriate solvent grade directly impacts defect density in subsequent process steps.

Isopropyl alcohol has emerged as the dominant solvent in semiconductor cleaning operations. Its exceptional water miscibility enables it to displace aqueous rinse residues completely. A low boiling point of 82.6 degrees Celsius and high vapor pressure facilitate rapid, residue-free drying. Most critically, its surface tension of approximately 23 millinewtons per meter, roughly one-third that of water, underlies the Marangoni drying process used in virtually all advanced fabrication facilities. In this technique, IPA vapor introduced at the water meniscus as the wafer withdraws creates a surface tension gradient that pulls the water film away from the surface, preventing watermark formation and feature collapse.

Acetone complements IPA with stronger solvency power for aggressive degreasing and hardened residue removal. Its rapid evaporation and excellent compatibility with most organic contaminants make it particularly useful for equipment cleaning and substrate preparation prior to coating operations. However, acetone's aggressive character demands careful attention to material compatibility, as it can attack certain plastics, rubbers, and photoresists. We supply electronic-grade acetone with metallic impurity controls suitable for semiconductor manufacturing environments.

Figure 4: A spin-rinse-dry system spraying deionized water onto a rotating wafer surface

Cleaning Processes and Corresponding Chemical Solutions

The table below maps principal cleaning applications to the chemical formulations that address them. This reference supports rapid identification of appropriate cleaning chemistries for specific contamination challenges.

Figure 5: A heated photoresist stripping bath with adjacent cascading rinse tanks

Representative Product Portfolio

The following selection illustrates the breadth of our cleaning chemicals offering. We encourage direct inquiry for products not explicitly listed, as our portfolio continually evolves to address emerging process requirements.

Custom Formulation and Process Support

Standard catalog products serve numerous routine applications, yet specialized cleaning challenges frequently benefit from tailored formulations. Our technical group works collaboratively with process engineers to develop custom cleaning solutions that address unique contamination profiles, material compatibility constraints, or equipment-specific requirements.

Previous customization engagements have included modified SC-1 and SC-2 ratios for non-standard substrates, low-temperature photoresist strippers compatible with temperature-sensitive materials, enhanced post-etch residue removers for novel interconnect stacks, and specialized solvent blends for unique drying applications. We also support private labeling, customer-specified packaging in fluoropolymer containers, and dedicated lot documentation to match internal quality systems.

To explore custom cleaning chemistry solutions for your specific requirements, please contact our applications engineering team with details of your target substrates, contamination types, and process conditions.

For Research or Industrial Raw Materials, Not For Personal Medical Use!