Product Name: Hexamethyldisilazane (HMDS)

Product Code: NV-SIM501

Alias: Bis(trimethylsilyl)amine;HMDS; HMDZ

Chemical Informations

Main Composition:1,1,1,3,3,3-Hexamethyldisilazane

Molecular Formula: C₆H₁₉NSi₂

Molecular Structure：

Cas No.:999-97-3

EINECS:213-668-5

Product Description:

HMDS (Hexamethyldisilazane) is a high-purity, clear, colorless liquid organic silicon compound widely recognized as one of the most efficient silylation agents in the chemical industry.

By introducing trimethylsilyl groups into polar molecules, it effectively replaces active hydrogens (such as in -OH, NH2, -COOH).

In the silicone industry, it is primarily used as a hydrophobic surface-treating agent for fumed silica to eliminate structural aging in silicone rubbers.

It also serves as a critical block-protecting intermediate in pharmaceutical synthesis and an adhesion promoter for photoresists in semiconductor wafer manufacturing.

Typical properties:

Appearance: colorless transparent liquid

Content:≥99%

Hexamethyldisiloxane content (%):≤0.5

Hydroxytrimethylsilane content (%):≤0.3

Cl content (PPM): ≤50

Refractive index: 1.4069-1.4089

Boiling Point: 125℃

Density (25℃,g/cm3)：0.770-0.780

Flash point: 27℃

Applications:

1.Semiconductor & Microelectronics Manufacturing (Primary Application)

Hexamethyldisilazane (HMDS) is widely used in the semiconductor industry as a photoresist adhesion promoter in wafer processing.

In semiconductor fabrication, HMDS is applied to silicon wafers (primarily silicon dioxide surfaces) via liquid or vapor-phase priming. It reacts with surface hydroxyl groups, converting the hydrophilic surface into a hydrophobic one.

This surface modification:

Enhances adhesion between photoresist and wafer substrates

Improves coating uniformity of photoresist films

Reduces pattern defects such as lift-off or peeling during development and etching

Contributes to improved process stability and yield

HMDS priming is a standard pre-treatment step in photolithography processes.

2.Protecting Group in Pharmaceutical & Fine Chemical Synthesis:

Highly active silylation agent widely deployed in the commercial production of semi-synthetic β-lactam antibiotics (e.g., Cephalosporins and Penicillins). It temporarily blocks active Hydroxyl (-OH) and Amine (-NH2) groups to secure high reaction selectivity and yield.

3.Material Modification & Surface Treatment

HMDS is widely used for the hydrophobic treatment of inorganic powders and fillers through surface silylation.

Typical materials include:Fumed silica,Silicon dioxide (SiO₂) ,Diatomaceous earth ,Titanium dioxide (TiO₂)

Surface treatment with HMDS reduces surface hydroxyl groups, resulting in:

Improved hydrophobicity

Enhanced dispersion in organic media

Reduced moisture absorption and agglomeration

Improved rheology and storage stability in formulations

4.Silicone Elastomers & Polymer Processing (Auxiliary Use)

In silicone rubber systems (e.g., LSR, RTV, HTV), HMDS Acts as an anti-structuring aging agent to prevent crepe hardening in LSR/HTV compounds.

It is used as a surface modifier for reinforcing fillers, particularly fumed silica.

Its functions include:

Improving filler dispersion in silicone matrices

Reducing viscosity increase caused by untreated fillers

Enhancing processing behavior and stability of silicone compounds

HMDS acts by reacting with silanol groups on filler surfaces, forming trimethylsilylated surfaces.

Package: 150KG/DRUM