Method for polish planarizing a semiconductor substrate by using a boron nitride polish stop

A method for polishing planarizing a silicon substrate having recessed regions and protruding regions comprising the steps of:

• depositing a boron nitride polish stop layer to overlie the substrate, the boron nitride polish stop layer having a hexagonal-close-pack crystal orientation;
• depositing at least one layer of filler material to overlie the boron nitride polish stop layer wherein the at least one layer of filler material has a polishing removal rate substantially greater than the boron nitride polish stop layer;
• placing the substrate in a polishing apparatus wherein the substrate is brought into contact with a rotating polishing wheel having a polishing pad disposed thereon;
• applying a silica slurry suspended in potassium hydroxide to the polishing pad;
• and
• polishing back the at least one layer of filler material until the polish stop is reached.

A method for forming a polish stop layer in a semiconductor fabrication process comprising:

• placing a semiconductor substrate in a plasma-enhanced-chemical-vapor-deposition (PECVD) reactor;
• heating the substrate to about 250.degree. to 400.degree. C.;
• flowing B.sub.2 H.sub.6, NH.sub.3 and a carrier gas into the PECVD reactor;
• applying about 1500 to 2000 Watts of RF power to an anode within the PECVD reactor;
• maintaining a total pressure of about 1 to 3 Torr within the reactor;
• and
• depositing a layer of boron nitride (BN) having a hexagonal-close-pack crystal orientation onto the semiconductor substrate.