PHOTORESIST ADHESION WITH HEXAMETHYLDISILAZANE
Purified hexamethyldisilazane (HMDS) preparations promoting photoresist adhesion on silicon and other substrates.
HMDS – X10
10% HMDS solution in xylene
HMDS – X20
20% HMDS solution in xylene
HMDS – 100%
- Ready-to-use preparations for surface treatment of silicon
- Promotes photoresist adhesion on silicon and SiO2 films
- Prevents lift-off at edges of photoresist and reduces undercutting
- Ensures full-line resolution
- Improves yields of MOS and integrated silicon devices
HMDS- Photoresist Adhesion with Hexamethyldisilazane
HMDS is a purified hexamethyldisilazane with the chemical formula [(CH3)2Si]2NH. The product is used to augment the adhesion of photoresist on silicon and SiO2 surfaces.
The effectiveness of HMDS on adhesion is correlated with the reactivity of this compound with surface hydroxyl groups to form a new siloxane end product, i.e. Si-O-Si(CH3)3. This newly formed termination on the substrate renders the surface more hydrophobic in character and leads to greater wettability by photoresist. The latter condition is a crucial factor in good bonding. As a result of these altered characteristics due to the surface chemistry, the treated silicon surfaces become highly compatible with both negative and positive photoresists.
HMDS is offered in usable concentrations diluted with xylene as HMDS-X10 and HMDS-X20. Special blends are supplied upon request.
PROPERTIES OF HMDS (ACTIVE INGREDIENT)
|Appearance||Clear, colorless liquid|
|Index of Refraction||1.4|
|Boiling Point||126-127 °C|
|Flash Point||12.7 °C|
|Sodium||< 1 ppm|
|Iron||< 1 ppm|
|Lead||< 1 ppm|
|Copper||< 1 ppm|
HMDS preparations are generally applied to the silicon wafer while spinning, prior to the application of photoresist. As an alternative procedure, the wafers may be immersed in HMDS preparations and allowed to dry after removal.