Silicon Etchant - MOS grade

Cat. No.: S1523752

QUALITÄT & REINHEIT MOS grade

Storage

Room temperature

Shipped In

Normal

Spezifikationen

Spezifikationen & Reinheit

MOS grade

Storage

Room temperature

Verschickt in

Normal

Note

MOS grade

Application Protocols

The following outlines a general wet silicon etch workflow for research labs. It is literature-based guidance and not specific to the composition of this item. Always adapt to your chemistry and consult the SDS/CoA.

• Pre-etch preparation:

  • Verify wafer type (orientation, doping) and mask material/thickness for required selectivity.
  • Pre-clean to remove organics/particles; if needed, remove native oxide (appropriate to your chemistry) immediately before etch.
  • Set up a temperature-controlled wet bench or fume hood; confirm container compatibility (PP, PTFE, PFA).

• Etching:

  • Use the etchant as supplied or dilute with high-resistivity DI water if your validated process calls for it (only if confirmed safe/appropriate for this SKU).
  • Control bath temperature within ±1 °C of your target. Provide gentle agitation or recirculation/filtration compatible with the chemistry.
  • Immerse the masked wafer; start timing when fully wetted. Avoid air entrapment; use megasonics only if compatible with mask/chemistry.

• Monitoring and completion:

  • Periodically inspect a test coupon or monitor wafer; verify feature depth and surface quality by profilometry/SEM.
  • When target depth is reached, transfer immediately to overflowing DI rinse bath; perform multiple rinse stages.

• Post-etch:

  • Neutralize or dispose per SDS and institutional procedures. Strip masks if required; dry wafers in IPA vapor dryer or filtered N2.

Pilot small-scale trials to determine etch rates and selectivity before production-scale runs.

Biological Roles

This product is a microfabrication etchant for silicon. It has no biological role or function and is not intended for any biological system.

• Item-specific facts (from Product Data): Research use only.
• General note: While etchants may be evaluated for toxicity and environmental fate for EHS compliance, they are not used as biomolecules, nutrients, or inhibitors in biological pathways.

No clinical or diagnostic use is intended or implied.

Buffer Applications

Not applicable. Silicon etchants are not used as biological or analytical buffers. If dilution is required, high-resistivity DI water is typically used in cleanroom processing (general guidance), but this is process chemistry, not buffering. Refer instead to Reaction & Applications and Reaction Conditions for relevant information.

Green Alternatives

Because the exact composition is not specified, selection of greener alternatives should be based on your process target (anisotropic vs isotropic etch, required selectivity, EHS constraints). Below are literature-based comparisons to guide choice; they are not item-specific specifications.

• General EHS considerations:

  • HF-containing systems: very effective but present severe acute toxicity and persistent risk; specialized training and PPE are required.
  • TMAH-based alkaline etchants: effective anisotropic etching but are acutely toxic to the nervous system; wastewater handling is critical.
  • KOH or choline hydroxide: corrosive but generally considered less systemically toxic than TMAH; still require robust controls.
  • Emerging options: Choline hydroxide and other quaternary ammonium bases with improved EHS profiles; deep eutectic solvents (DES) under exploration for silicon processing; dry plasma (fluorine chemistry) can avoid liquid handling but introduces other hazards and energy use.

• Small comparison (literature, illustrative):

  • KOH (aq): Anisotropic; inexpensive; corrosive; metal ion contamination must be managed in MOS contexts.
  • TMAH (aq): Anisotropic; good CMOS cleanliness profile; acutely toxic; requires strict wastewater controls.
  • Choline hydroxide (aq): Anisotropic; greener alternative to TMAH; process windows still maturing in some fabs.
  • HF/HNO3/CH3COOH: Fast isotropic bulk Si removal; severe HF hazards; complex off-gassing; strong fume control required.
  • Dry plasma (SF6/C4F8): Isotropic/aniso by tuning; no liquid waste; requires vacuum tools and line gases; potential polymer residues.

Choose based on your EHS policy, selectivity needs, and tool availability; confirm compatibility with device materials and masks.

Pharmaceutical Uses

Not applicable. Silicon etchants are not pharmaceutical excipients or actives. They are specialized materials-processing reagents for semiconductor and materials science research.

• Regulatory note: Use is limited to research/laboratory applications. No GMP or pharmacopeial status is implied. Refer to your institutional EHS policies for handling and disposal of corrosive or toxic etchants.

Physical Properties

• Item-specific facts (from Product Data):

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Storage conditions: Room temperature (as supplied).
  • Shipping: Normal.
  • All other specifications (density, viscosity, pH, conductivity, water content, metal content, UV cutoff): Not specified for this item; refer to CoA/Spec Sheet.

• Literature/general ranges (examples for context only; not specifications for this item):

  • Alkaline silicon etchants (e.g., aqueous KOH or TMAH) are typically clear liquids with density ~1.03–1.35 g/mL depending on concentration; pH > 13; viscosity modestly above water; boiling point near water but elevated with concentration.
  • Fluoride-based silicon etchants (HF-containing) are typically clear aqueous solutions; density ~1.00–1.20 g/mL depending on HF content; very low surface tension relative to water if surfactant is present (process-dependent).
  • Temperature dependence: Silicon etch rates commonly increase strongly with temperature (Arrhenius behavior); typical process baths for anisotropic alkaline etching run ~60–90 °C (literature), whereas isotropic HF/HNO3 systems are often operated near ambient under fume hood (literature).

• Solubility/miscibility (general):

  • Most commercial wet silicon etchants are water-based and fully miscible with DI water; compatibility with organic solvents is formulation-dependent.

Note: Use the specific CoA/Spec Sheet for this SKU to obtain exact property values required for process qualification; the above are illustrative literature values only.

Quality and Grades

• Item-specific facts (from Product Data):

  • Grade: MOS grade (microelectronics/semiconductor grade).

• What MOS grade implies (general/industry understanding):

  • MOS (metal–oxide–semiconductor) grade products are intended for semiconductor processing where ionic contamination, particulate burden, and metallic impurities must be tightly controlled to protect device performance (e.g., leakage, corrosion, and defects). While the exact impurity limits for this SKU are not specified here, MOS grade typically targets very low alkali/alkaline-earth metals, transition metals, and particles. It may also emphasize low organic residues and compatibility with cleanroom wet benches.

• Stabilizers and additives:

  • Not specified for this item; refer to CoA/Spec Sheet. Some silicon etchants include surfactants or corrosion inhibitors to tune wetting and selectivity; verify in the product documentation before use in critical processes.

• Quality control suggestions (user guidance):

  • Verify ionic contamination and metal content meet your node requirement via CoA (e.g., ICP-MS panels), and confirm particle counts by light-scattering methods if your line requires sub-100 nm cleanliness.
  • Request/retain lot-specific CoA and SDS; perform incoming QA (etch rate on monitor wafers, roughness/defectivity checks, and mask selectivity tests) before qualifying in production.

• Regulatory/cleanroom considerations:

  • Use in designated wet etch areas, with appropriate containers (e.g., PFA/PP) and point-of-use filtration compatible with the chemistry (0.2–0.05 µm typical for critical cleaning).

Reaction and Applications

• Item-specific scope:

  • This MOS-grade Silicon Etchant is intended for research use in materials science and microfabrication workflows involving silicon pattern transfer and surface micromachining. Specific performance characteristics (etch rate, selectivity, roughness) are not specified for this item; verify via CoA/Spec Sheet and process trials.

• Typical applications (literature/general):

  • Anisotropic wet etching of crystalline silicon to produce V-grooves, cavities, diaphragms, and microchannels in MEMS, leveraging slow-etching {111} planes versus faster {100}/{110} planes (with alkaline etchants such as KOH/TMAH/choline hydroxide).
  • Isotropic silicon etching for texture or bulk thinning with oxidizer/acid mixtures; used in solar texturing and microstructuring (fluoride-based systems).
  • Pattern transfer beneath hard masks (SiO2, Si3N4) or certain metal masks; mask selection depends on chemistry and temperature.
  • TSV/through-etching assistance, wafer thinning, texturing, and stress relief features.

• Practical tips (general):

  • Crystal orientation matters: Etch profiles, undercutting, and stop planes depend on wafer orientation and doping; heavy p+ doping can reduce alkaline etch rates (literature).
  • Agitation and temperature control strongly influence etch rate and uniformity. Use recirculating temperature-controlled baths with filtration compatible with the chemistry.
  • Surface conditioning (native oxide removal or pre-clean) can standardize etch initiation; rinse protocols (DI cascade) and post-etch neutralization are critical to limit contamination.

• Integration notes:

  • Ensure compatibility with photoresists: Many wet silicon etchants attack or swell common resists; hard masks (SiO2/Si3N4) often preferred. Validate mask selectivity and critical dimension (CD) control with short pilots.

Reaction Conditions

Because composition is not specified, the following are literature-based, general operating windows for common silicon wet etches. They are not specifications for this item—validate with the CoA/Spec Sheet and pilot tests.

• Anisotropic alkaline etching (e.g., KOH, TMAH, choline hydroxide):

  • Temperature: ~60–90 °C accelerates etch rate and improves uniformity; tighter CD control often near 70–80 °C.
  • Concentration effects: Moderate concentrations frequently balance etch rate and surface roughness; very high concentrations can reduce etch rate due to reduced water activity (system-dependent).
  • Crystal dependence: {100} > {110} >> {111} etch rate; p+ regions may etch slowly.
  • Masks: Low-stress LPCVD Si3N4 often preferred; thermal SiO2 usable with limited selectivity; photoresist generally poor in hot base.

• Isotropic HF-based or oxidizer/acid systems:

  • Temperature: Often ambient to slightly elevated; strong fumes require excellent ventilation.
  • Rate control: Adjust oxidizer and HF content; agitation and fresh chemistry sustain high rates.
  • Masks: Many metals and glasses are attacked—choose compatible masks; PTFE or certain polymers for tooling.

• Process best practices (general):

  • Use clean DI rinses (cascade or overflow) post-etch; consider quench in copious DI prior to neutralization.
  • Measure etch rate on monitor wafers of the same orientation/doping as product wafers.
  • Implement point-of-use filtration; monitor bath aging and contamination (ICP-MS, TOC as appropriate).

All conditions must be tailored to your toolset, mask, and device stack.

Safety and Handling

• Item-specific hazard data (from Product Data):

  • Signal word, H-statements, GHS classification, pictograms: Not specified for this item; refer to SDS.

• Critical safety note:

  • Silicon etchants span a wide hazard spectrum depending on composition. Without the SDS, assume strong corrosivity and implement robust controls. Some formulations may contain HF or other fluorides (severe dermal/ocular/systemic toxicity), or strong bases such as KOH/TMAH (corrosive; TMAH solutions are acutely toxic and neurotoxic). This is general safety information (literature), not item-specific.

• General PPE and engineering controls (good practice):

  • Chemical fume hood or certified wet bench with local exhaust; splash protection (face shield over chemical goggles), acid/base-resistant gloves as appropriate for the chemistry (double-gloving recommended), chemically resistant apron, sleeves, and closed footwear.
  • HF possibility: If there is any chance the formulation contains HF, use calcium gluconate gel availability and HF-specific training; select appropriate gloves (e.g., heavier nitrile/neoprene; consult glove charts).
  • Strong base possibility: For alkaline etchants, use alkali-resistant gloves and eye/face protection; avoid aluminum/zinc contact.

• Incompatibilities (general):

  • Avoid contact with metals that dissolve in strong base or acid; avoid glassware with fluoride-based etchants; segregate from oxidizers and acids/bases as appropriate to the formulation.

• First-aid overview (general):

  • Skin/eye contact: Immediate water rinse for at least 15 minutes; remove contaminated clothing. HF exposures require specialized response per SDS and institutional protocol.
  • Inhalation/ingestion: Move to fresh air; seek medical attention immediately.

Always defer to and follow the product SDS for authoritative hazard, handling, spill, and disposal instructions.

Solvent Selection

This product is an etchant, not a general-purpose solvent, so solvent selection per se is not directly applicable. However, solvent/compatibility considerations are critical for process integration.

• Item-specific facts (from Product Data):

  • None specified regarding diluents or cosolvents; refer to CoA/Spec Sheet.

• General compatibility and wetting (literature/general):

  • Most silicon etchants are aqueous and are used as supplied or diluted with high-resistivity DI water. Wetting and bubble release on hydrophobic silicon or patterned resists can be improved with surfactants (if present in the formulation) or by pre-wetting/rinsing.
  • Container compatibility: Use plastic labware compatible with the chemistry (e.g., PP, HDPE, PTFE, PFA). Avoid glass for fluoride-based chemistries; avoid aluminum/zinc for strong bases/acids.

• When to choose alternative chemistries (selection logic):

  • For anisotropic etching with crystal-plane selectivity {111} vs {100}: alkaline systems (e.g., KOH, TMAH, choline hydroxide) are commonly selected (literature).
  • For isotropic bulk Si removal or texturing at ambient: oxidizer/acid (HNO3/HF/CH3COOH) or HF-based systems are used (literature).
  • For native oxide removal specifically: dilute HF or buffered oxide etch (BOE) is typically used; this is distinct from bulk silicon etch (literature).

Consult the SDS/CoA to confirm what diluents and contact materials are appropriate for this specific SKU.

Storage and Reconstitution

• Item-specific facts (from Product Data):

  • Storage conditions: Room temperature.
  • Shipped in: Normal conditions.
  • Reconstitution: Not specified for this item; refer to CoA/Spec Sheet.

• General guidance (literature/best practice for wet etchants):

  • Store in original, tightly closed container compatible with the chemistry (typically PP, HDPE, PTFE, or PFA). Keep in a corrosives cabinet or designated wet-etch chemical storage area away from incompatible materials.
  • Protect from contamination: use cleanroom handling, secondary containment, and point-of-use filtration if your process requires low particle counts.
  • Do not mix with other chemicals unless directed by the product documentation. If the product is a concentrate (unknown here), prepare dilutions only with high-resistivity DI water using clean containers; add acid/base to water as appropriate for the chemistry and per SDS.
  • Label opened containers with open date and track bath age/use cycles if transferred to process tanks. Avoid prolonged exposure to air if composition is sensitive to CO2 uptake or evaporation (check SDS/CoA).
  • Avoid freezing/heating beyond recommended ranges; maintain room temperature unless your process specifies otherwise.

For definitive storage, stability, and any reconstitution/dilution instructions, consult the lot-specific CoA and SDS for this SKU.

Structure and Identity

This product is a formulated silicon etchant for microfabrication and materials processing. Its exact chemical composition is not disclosed in the Product Data.

• Item-specific facts (from Product Data):

  • Product name: Silicon Etchant (SKU: S1523752)
  • Grade: MOS grade (microelectronics/semiconductor processing grade)
  • Composition: Not specified for this item; refer to CoA/Spec Sheet and SDS.
  • CAS, InChIKey, SMILES: Not applicable to a proprietary or unspecified mixture; not provided.

• Structural features (general knowledge):

  • Silicon etchants are typically aqueous solutions containing bases (e.g., KOH, TMAH, choline hydroxide), or fluoride-based systems (e.g., HF-containing formulations), or oxidizer/acid mixtures for isotropic etching. Because composition here is unspecified, these are examples (literature), not item-specific.

• 2D description (general):

  • As a mixture, no single molecular structure applies. If alkaline, the active species are hydroxide ions; if fluoride-based, fluoride complexes (e.g., HF2−) participate. Always consult the SDS/Spec Sheet to identify the actual actives in this item.

• Molecular formula and molecular weight: Not applicable to a mixture; not specified for this item.

Synthetic Utility

Classical organic or inorganic synthetic utility is not the focus for this product. Its value lies in materials processing (wet chemical micromachining of silicon).

• Materials-processing utility (general/literature):

  • Enables creation of microfeatures with crystallographic control (anisotropic alkaline systems) for MEMS sensors, microfluidic channels, and optical V-grooves.
  • Facilitates isotropic thinning or texturing of silicon surfaces.
  • Selectivity to masks (SiO2/Si3N4/metals) can be exploited to transfer high-fidelity patterns.

• Retrosynthetic perspective: Not applicable. For device fabrication retrosynthesis, consider mask stack engineering and etch-stop strategies (e.g., boron-doped etch stops or SOI buried oxide) rather than chemical synthesis per se.

For chemical synthesis building blocks and transformations, refer to other product categories.

Target Specificity

Not applicable. This is not a biological targeting reagent or antibody. There is no antigen, epitope, species reactivity, clone, or isotype associated with this product.