Dual Vacuum System for 2x Sio2 Sputtering Machines
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
This invention provides a new design which improves speed and efficiency of SiO2 sputtering machines used in semiconductor manufacturing processes. The SiO2 deposition chambers require conditioning and burn- in after a tooling change and before deposition of insulation on product. Previously, diffusion pumps were used during burn-in, and contamination resulted. The proposal suggests use of a mechanical pump and roots blower combination for burn-in and a cryopump and LN2 (liquid nitrogen) Meissner for pumping during deposition. The new design, which departs from traditional vacuum pumping systems, is shown in the figure. Peak efficiencies can be obtained in each of the three pressure ranges of interest: B = 760 mm to 1 Torr; C = 1 to 8 x 10-5 Torr; D = 8 x 10-5 to 5 x 10-8 Torr.