Deep Trench Filling With Buried Seam
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-12
The development of deep dielectric isolation requires the filling of both deep and shallow trench structures 10 with an insulator 11, usually low pressure chemically vapor deposited (CVD) SiO(2). During this filling operation, the silicon dioxide deposits on the vertical walls as well as on the horizontal surfaces, as shown in Fig. 1. As the filling proceeds, a seam can form where the sidewalls meet and can reappear when the silicon dioxide is etched back to the silicon surface; this seam etches much faster than the rest of the silicon dioxide, causing a groove 12 in the center of the trenches, as seen in Fig. 2. This groove is undesirable since it leads to discontinuous metal lines.