Non-Thermal E-Beam Direct Write of Via Holes
Original Publication Date: 1985-Jan-01
Included in the Prior Art Database: 2005-Feb-18
One process for the formation of via holes involves these steps: 1. Apply resist. 2. E-beam expose with via pattern. 3. Develop pattern (to obtain sidewall angles of 80-90 degrees). 4. Thermally flow resist to taper sidewall angles to less than 70 degrees. 5. Harden the resist. 6. Plasma etch. The method described here is proposed to eliminate Step 4 by directly writing tapered sidewall angles into the resist with the E-beam in Step 2. Figs. 1A to 1C and Table 1 illustrate the spot patterns used in the E-beam direct write of tapered sidewall angles. A novel feature is that the spots must overlap, as shown in Fig. 2. Fig. 3 illustrates the two-dimensional cross-section of a modelling system for predicted sidewall angles for various doses (see Table 2) given to the spot patterns in Figs. 1A to 1C. Fig.