Chemical Vapor Deposition of Tungsten to Fill Oversize Vias
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
A technique is shown for filling various contact hole sizes while at the same time optimizing the electrical properties of the film. Chemical vapor deposition (CVD) contact metal thickness is controlled as a function of the electrical properties, such as resistance and capacitance, required by the given design. Filling various size contact holes is a concern in certain designs, where contacts may carry varying amounts of current or require low contact resistance. Contact hole size must be independent of film thickness for all VLSI technologies to avoid performance degradation. Three different size contact holes are shown in Fig. 1. A hole having a width less than X, and a hole having a width of X, is filled by a CVD metal having a thickness of one-half X. A hole having a width greater than X is not filled during this step.