HMDS Coating Machine  HMDS Coating Oven  Intelligent HMDS Pretreatment SystemPrinciple:

HMDS-coated ovens are used for wafer hydrophobic treatment in photolithography processes. The principle of HMDS coating is that the most commonly used adhesive is hexamethyl disilazane (HMDS). In the process of enhancing the adhesion of photoresist, hexamethyl disilazane itself does not act as a binder, but rather HMDS alters the interface structure of SiO2, transforming the wafer's properties from hydrophilic to hydrophobic surfaces.

The adhesion issue between photoresist and wafer surface is influenced not only by molecular bonding but also by other significant factors. Surface moisture is a key factor among them, which reduces adhesion and can lead to lifting of resist and lateral corrosion. HMDS coating is a surface treatment applied before applying the photoresist, which can increase the contact angle of water molecules on the wafer surface, transforming the surface from hydrophilic to hydrophobic.

The HMDS coater employs steam coating technology. To simply evaluate the adhesion quality of the wafer surface, you can coat the wafer with HMDS, then drop a water droplet on the wafer surface. By measuring the contact angle of the water droplet, you can determine the adhesion quality of the wafer surface. The method for measuring the contact angle is shown in the figure below. The larger the contact angle, the better the adhesion, indicating a stronger hydrophobic nature.

HMDS Coating Machine  HMDS Coating Oven  Intelligent HMDS Pretreatment SystemTechnical Specifications:

HMDS Coating Machine, HMDS Coating Oven, Manufacturer of Intelligent HMDS Pretreatment Systems