Choline Hydroxide

E-GRADE® Choline Hydroxide is a clear aqueous solution with a high pH and a mild odor. It has a very low corrosion rate on copper and other metallic surfaces and has been demonstrated to effectively remove both positive and negative photoresists. The product is an effective replacement for TMAH and is available in higher concentrations than TMAH in both water and organic solvents (for R&D). The combination of low corrosion rates, photoresist removal, etching, and lower toxicity makes E-GRADE® Choline Hydroxide an effective, safer-to-handle alternative to TMAH in next-generation semiconductor cleans, with performance enhancements such as faster photoresist removal rates and selective metal removal rates.

Functions: Etchant

Chemical Family: Quaternary Ammonium Compounds

End Uses: Semiconductor, ̇Photoresists

Applicable Processes: Etching Applications, Metal Removal

Features: High Purity, High pH, Low Corrosion, Low Toxicity

Safety Data Sheet

Enhanced TDS

Identification & Functionality

Features & Benefits

Industrial Additives Features
Product Features
  • Organic base
  • High purity, low trace metal
  • Available at 45 wt%
  • Water or solvent based
  • TMAH replacement
  • Developer, stripper, and PERR
  • Etching agent
  • CMP slurries and pCMP Cleans

Applications & Uses

Properties

Physical Form
Notes

* Thickness measured with Napson Cresbox 4 point-probe tester and Filmetrics.

Regulatory & Compliance

Technical Details & Test Data

Treatment of Copper Wafer

E-GRADE® THEMAH - 1 - 1

  • Cu wafer treated with E-GRADE® THEMAH and E-GRADE® CHOLINE HYDROXIDE demonstrated smoother surfaces comparing to Cu treated with TMAH.
TMAH diagram
  • Silicon wafers, etched with E-GRADE® Choline Hydroxide, demonstrate significant reductions in reflectivity and improvement in uniformity when compared to wafers treated with TMAH. This texturization reduces light reflection and improves absorption for photovoltaic devices.

Choline Hydroxide - TMAH diagram - 1

  • Positive tone Novolak photoresist is well developed at room temperature with E-GRADE® Choline Hydroxide.

Choline Hydroxide - TMAH diagram - 1

pH Dependance
  • Concentration dependence of pH values for TMAH and Choline in water.

Choline Hydroxide - pH Dependance - 1

TiN Etch with Hydrogen Peroxide
  • At proper pH and concentration, E-GRADE® Choline Hydroxide with H₂O₂ can be used for TiN etch (etch rate > 20 nm/min). The degradation rate of H₂O₂ with Choline Hydroxide was observed to be much slower than with TMAH. Degradation rate is based on 24 hr average at 45°C.

Choline Hydroxide - TiN Etch with Hydrogen Peroxide - 1

H₂O₂ (wt %) Quat pH at 45℃ TiN (nm/min) Cu (nm/min)

H₂O₂ degradation (%/hr)

8.0% TMAH 7.96 18.67 -0.31 0.071
COH 8.05 19.02 0.39 0.058
9.6% TMAH 8.07 33.3 0.66 0.148
COH 8.03 24.66 0.47 0.098
Photoresist Development - Concentration Dependence

E-GRADE® THEMAH - Photoresist Development - Concentration Dependence - 1

  • Choline Hydroxide, XHE-125, and XHE-128 have comparable developing rates relative to 2.38 wt% TMAH for positive PR
  • Developing rates can be optimized across a broad working window
  • Developing rates are linear with concentration, above a minimum concentration

E-GRADE® THEMAH - Photoresist Development - Concentration Dependence - 1

  • Choline Hydroxide demonstrated good performance for negative PR
  • XHE-125 has similar performance, increasing the concentration to 5 wt% to match 2.38 wt% TMAH
  •  Developing rates have a linear relationship with concentration, even at low concentrations

Packaging & Availability

Regional Availability
  • Global

Other

Appearance (SDS)
Liquid
Color (SDS)
Clear
Odor (SDS)
Mild amine-like
Chemical Properties
ValueUnitsTest Method / Conditions
pH2.58-
Physical Properties
ValueUnitsTest Method / Conditions
Molecular Weight121.0 g/molg/mol