Chemical Cleaning
chemicalCleaning.desc
Overview
Chemical cleaning is the foundational process step enabling every subsequent fabrication operation — from epitaxial growth to lithography to wafer bonding. GINECHIP operates a comprehensive wet bench facility delivering RCA standard clean (SC-1/SC-2), Piranha clean, HF-last, and megasonic cleaning for wafers from 100mm to 300mm in an ISO Class 1 cleanroom environment.
Our multi-chemistry wet bench platform supports batch processing up to 50 wafers and single-wafer processing for critical applications. Real-time chemical concentration monitoring, automated dosing, and in-line particle counting ensure process consistency and repeatability across every lot.
Cleaning Services
RCA Standard Clean
The industry-standard RCA clean sequence removes organic contaminants, particles, and metallic impurities. SC-1 (NH₄OH/H₂O₂/H₂O) removes organics and particles, while SC-2 (HCl/H₂O₂/H₂O) removes metallic contaminants. Megasonic agitation enhances particle removal efficiency.
Piranha Clean (SPM)
Sulfuric acid-hydrogen peroxide mixture aggressively removes heavy organic contamination, photoresist residues, and biological materials. The exothermic reaction reaches 120-150°C, providing rapid and complete organic removal. Commonly used as the first step in pre-diffusion and pre-epitaxial cleaning sequences.
HF-Last Clean
Final hydrofluoric acid dip removes native oxide and produces a hydrogen-terminated, hydrophobic silicon surface. This atomically clean surface is essential for epitaxial growth, metal deposition, and direct wafer bonding. Oxide regrowth is delayed for 4-8 hours.
Megasonic Cleaning
High-frequency (0.8-1.2 MHz) acoustic energy creates microscopic cavitation-free streaming that dislodges sub-micron particles without damaging delicate device structures. Compatible with SC-1, SC-2, and DI water chemistries in both single-wafer and batch configurations.
Marangoni Drying
Gradient surface-tension drying eliminates water marks by introducing IPA vapor above the wafer surface as it is slowly withdrawn from DI water. The surface tension gradient pulls water off the wafer, leaving a completely dry, spot-free surface.
Process Flow
Incoming Inspection
Visual inspection, wafer ID verification, and initial surface condition assessment before chemical processing.
SPM Organic Removal
Piranha clean removes organic residues, photoresist, and surface hydrocarbons at 120-150°C.
HF Native Oxide Strip
Dilute HF removes native oxide, exposing bare silicon surface for subsequent cleaning steps.
SC-1 Particle Removal
Ammonium hydroxide-hydrogen peroxide mixture with megasonic agitation removes particles down to 0.1μm.
SC-2 Metal Removal
Hydrochloric acid-hydrogen peroxide mixture removes metallic contaminants below 1×10¹⁰ atoms/cm².
HF-Last Surface Passivation
Final HF dip creates hydrogen-terminated hydrophobic surface ready for subsequent processing.
Marangoni Dry & Inspection
Spot-free Marangoni drying followed by laser surface scan for particle certification and final quality release.
Quality Specifications
| Parameter | Target Spec | Method |
|---|---|---|
| Particle Count | ≤ 10 adds @ 0.2μm | KLA-Tencor Surfscan SP2/SP3/SP5 |
| Iron (Fe) | < 1×10¹⁰ atoms/cm² | TXRF / VPD-ICP-MS |
| Copper (Cu) | < 5×10⁹ atoms/cm² | TXRF / VPD-ICP-MS |
| Nickel / Chromium (Ni/Cr) | < 1×10¹⁰ atoms/cm² | TXRF / VPD-ICP-MS |
| Surface Roughness | < 0.15nm (Si substrate) | AFM (2μm × 2μm scan) |
| Native Oxide | < 0.7nm (HF-last) | Spectroscopic ellipsometry |
| Contact Angle | > 70° (hydrophobic) | Goniometer |
| Organic Residue | < 1 monolayer equivalent | XPS survey scan (C 1s peak) |
All measurements performed in ISO Class 1 cleanroom. Specifications verified per lot with certificates of analysis provided.
Cleaning Chemistry
SC-1 (Standard Clean 1)
The SC-1 process uses an ammonium hydroxide-hydrogen peroxide mixture at 75–80°C to remove organic contaminants and particles. The alkaline chemistry oxidizes and etches a thin silicon layer, lifting particles from the surface through controlled undercutting. Megasonic agitation enhances particle removal efficiency for sub-0.2μm particles.
SC-2 (Standard Clean 2)
The SC-2 process uses a hydrochloric acid-hydrogen peroxide mixture at 75–80°C to remove metallic contaminants. The acidic chemistry dissolves and complexes metal ions, achieving contamination levels below 1×10¹⁰ atoms/cm². SC-2 is essential after SC-1 to remove metals introduced during the alkaline cleaning step.
Application-Specific Protocols
Pre-Diffusion Clean
Pre-diffusion cleaning removes metallic impurities to levels below 1×10¹⁰ atoms/cm², preventing contamination of high-temperature diffusion and oxidation furnaces. Our RCA-based cleaning sequences meet the stringent requirements of CMOS and power device fabrication.
Pre-Epitaxial Clean
Pre-epitaxial cleaning achieves atomically clean silicon surfaces required for high-quality epitaxial growth. The process removes native oxide, organic contamination, and metallic impurities while maintaining surface smoothness below 0.2nm RMS. The HF-last step creates a hydrogen-terminated surface ideal for epitaxial nucleation.
Pre-Bond Clean
Pre-bond cleaning removes organic contaminants, particles, and native oxide from wafer surfaces to ensure void-free bonding with maximum bond strength. Our cleaning recipes are optimized for anodic, fusion, eutectic, and adhesive bonding processes with surface roughness maintained below 0.15nm RMS.
Contamination Control
Our contamination control program encompasses chemical purity management, environmental monitoring, and statistical process control. All chemicals are semiconductor-grade, DI water resistivity exceeds 18.2 MΩ·cm, and cleanroom particle counts are continuously monitored to maintain ISO Class 1 conditions.
Chemical Purity
All process chemicals are SEMI Grade 2 or higher, with trace metal certification below 1 ppb for critical elements. Chemical baths are monitored in real-time for concentration, temperature, and contamination buildup.
Tooling & Automation
Fully automated wet bench systems with robotic wafer handling ensure consistent process execution, eliminate manual handling defects, and provide complete process traceability. Each cleaning cycle is monitored and recorded with real-time chemical concentration and temperature data.
Substrate Compatibility
Our cleaning processes are compatible with silicon, SOI, glass, quartz, sapphire, SiC, GaAs, InP, GaN, and ceramic substrates. We select cleaning chemistries and process parameters based on your substrate material and device sensitivity. Dedicated process tanks prevent cross-contamination between material types.
Particle Removal Performance
Our multi-step particle removal process combines megasonic agitation, brush scrubbing, and chemical cleaning to achieve particle removal efficiency exceeding 99% for particles down to 0.2μm, meeting the requirements of advanced lithography and epitaxial growth.
Quality & Certification
Our quality assurance program includes liquid particle counting, metal contamination analysis by ICP-MS, surface contact angle measurement, and visual inspection with automated defect classification. Each cleaned lot is certified to your cleanliness specifications.
Need Wafer Cleaning Services?
Contact our engineering team to discuss your specific cleaning requirements and receive a detailed quotation within 24 hours.