| 摘要 |
A scheme for forming a thin metal interconnect is disclosed that minimizes etch residues and provides a wet clean treatment for via openings. A single layer interlayer dielectric (ILD), BARC, and photoresist layer are successively formed on a substrate having a copper layer that is coplanar with a dielectric layer. In one embodiment, the ILD is silicon nitride with 100 to 600 Angstrom thickness. After a via opening is formed in a photoresist layer above the copper layer, a first RIE process including BARC main etch and BARC over etch steps is performed. Then a second RIE step transfers the opening through the ILD to uncover the copper layer. Photoresist and BARC are stripped with oxygen plasma and a low DC bias. Wet cleaning may involve a first ST250 treatment, ultrasonic water treatment, and then a third ST250 treatment. A bottom electrode layer may be deposited in the via opening.
|
