General Chemical Handling Policies: Guidelines for handling chemicals at any wet bench. Click <here>.

Oxide Etch: Because of specific materials issues, different procedures for wet etching of oxide exist at each wet bench. Click on the appropriate wet bench for the specific wet oxide etch protocol: wbnonmetal, wbmetal, wbgeneral. For typical etch rates of oxides and other films in some standard etchants, click <here> and <here>.

Triton X-100: This is a surfactant, sometimes added to BOE to aid in etching small features. Use of Triton-X100 is restricted to the following wet benches: wbnonmetal, wbmetal, and wbgeneral.

Photoresist Strip: The specific procedure to remove photoresist from wafers will depend on the substrate, the films on the wafer, and materials issues, and the processing that the resist received (implants, certain plasma etches). Some of the common resist strip procedures are listed <here>.

Cleans are generally performed on materials just prior to film deposition or other furnace processes. The specific clean procedures to be performed and which wet bench should be used will depend on the substrates, any materials issue, and the specific type of deposition of furnace process to be performed. Pre-diffusion tube processing or pre-LPCVD/pre-Metal processing cleans for non-metal containing wafers are similar, but differ in the ordering of the clean steps, depending on whether a film is to be deposited or not. Metal-containing wafers that are to be processed in a furnace, LPCVD, or metal deposition systems require a different set of clean procedures. Clean procedures are restricted to specific wet benches, and the details will vary between wet benches:

Tweezer Clean: Tweezers for handling substrates are cleaned, classified, and used according to the degree of contamination of subsequent processing steps, as defined by SNF Materials Policies.

Silicon Wet Etching is commonly done using KOH or TMAH. Any such non-standard processing must be done at wbgeneral. Any devices processed using KOH etching need to be decontaminated before re-entering the standard process line (click <here> for information about materials restrictions on various equipment tools). For more detailed information about this and other methods for micromachining silicon, click <here>. Wet etching is preferred for bulk micromachining of silicon and for processes in which etch anisotropy along different crystal planes in exploited; however, plasma etching of silicon can also be done at SNF.

Non-Standard Nitride Strip: Nitride Wet Etching is done with hot phosphoric acid. Standard processing of "clean" wafers takes place at wbnitride. Nitride removal from non-standard processed materials is done at wbgeneral. Thin nitride films can also be removed with plasma etch. For wet etch rates of nitride films in some standard etchants, click <here>.

Click <here> for links to the specific wet benches.