Etch Resist Waxes

By APIEZON

Apiezon Wax W is an ideal etch resist. Apiezon Wax W is perhaps most extensively used as an etch resist in the electronics industry for both semi conductor and PCBs. Its wide operating temperature range and low vapour pressures mean it also has an excellent track record in many other different applications, and is the most versatile product in the Apiezon Wax range. Also known as ‘Black Wax’, Apiezon Wax W manufactured by M&I Materials Ltd, has an excellent resistance to etching fluids up to 75°C in all sorts of etchants, including KOH, TMAH, EDP, HF, HNO 3, NaOH and acetic acid, but can still be easily removed using hydrocarbon solvents. The powerful ‘gettering’ qualities of Apiezon Wax W also mean that during post-etch cleaning steps, impurities which may have remained on the surface if a solvent were used in isolation, are also removed with the wax. Furthermore the hydrocarbon formulation and very ‘clean’ meltdown properties of the wax ensure that unwanted etching contaminates are not introduced into the system. Q: How do I apply Apiezon W Wax for etch resist applications? Apply pre-melted wax to the required area using a glass rod, spatula or other similar implement, taking care not to exceed 60°C above the softening point of the wax shown in the table opposite. Alternatively dissolve the wax in a hydrocarbon solvent prior to use. Evaporation of the solvent will leave a thin layer of wax with excellent adhesive properties. To ensure an adhesive layer of uniform thickness, rapidly rotate the chip and a superior mounting surface will be created. Q: How do I remove Apiezon W Wax used for etch resist applications? A: To remove the wax after use, simply heat, soften and scrape away larger amounts. Any deposits can then be dissolved away by using any aromatic hydrocarbon solvent (toluene, xylene), or removed using a vapour degreasing bath. Apiezon waxes are not soluble in alcohols (ethanol, IPA) or ketones (acetone, MEK) so these cannot be used for cleaning.