Graded Step Crossing by Laser Chemical Vapor Deposition
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
In microelectronic circuitry, it is often necessary that two conducting lines cross over one another, where there must be insulation between the conducting lines at the cross-over point. In order to avoid electrical shorts between the lines, or open circuits in each of the lines where the wiring layers cross, the thickness of the successive layers of metallurgy and insulation is generally increased from the bottom to the top. The standard technique for layers of x-wiring, interlevel insulation I, and y-wiring is shown in Fig. 1, and calls for a graded thickness x < I < y. For example, in Fig. 1 the ratio x:I:y is 1:2:3. If this ratio is varied, it is possible to introduce electrical shorts between the x and y levels, or electrical opens in the y-wiring level.