Stepper Lithography Recipes

Below is a listing of stepper lithography recipes.  Based on your sample reflectivity, absorption, and surface topography the exposure time / focus offset parameters may vary. This listing is a guideline to get you started.  The recipes are tabulated to give you the values of the key parameters you will need to establish your recipe. For wafer cleaning and preparation including HMDS use, please refer to the cleaning and preparation section in the lithography section of this web site. Post develop bakes (not listed) are used to make the resist more etch resistant and depend on subsequent processes. Care should be taken with post development bakes as resist reflow can occur. Unless otherwise noted, all exposures are done on flat, silicon wafers.

Parameters are indicated in separate tables for each stepper system. Multiply the exposure times by 0.30 (from the 6300 system) to get a starting exposure time for the GCA Autostep200 system. You will need to do an exposure array to get precise times for the Autostep system. In general, the resolution achievable is ~ 100 nm smaller for the Autostep200 system.

Positive Resist

Unless otherwise noted, bakes are on hot plates. For recipes with CEM, the CEM is spun on after the first resist bake, exposure is then done, and the CEM is rinsed off with DI water before the PEB. CEM generally improves resolution and process tolerance at the expense of higher exposure time.

GCA 6300

Negative Resist

Unless otherwise noted, bakes are on hot plate. All flood exposures are done in broadband light using any contact aligner. Also, because the tone is negative, a shorter first exposure time will result in more undercut, which is desirable for single-layer lift-off processes. Under these conditions more develop time will also give more undercut.

GCA6300