Abstract: In a polish palnarization process using a polishing apparatus and an abrasive slurry, a boron nitride (BN) polish stop layer (18) is provided to increase the polish selectivity. The BN layer deposited in accordance with the invention has a hexagonal-close-pack crystal orientation and is characterized by chemical inertness and high hardness. The BN layer has a negligible polish removal rate yielding extremely high polish selectivity when used as a polish stop for polishing a number of materials commonly used in the fabrication of semiconductor devices. In accordance with the invention, a substrate (12) is provided having an uneven topography including elevated regions and recessed regions. A BN polish stop layer (18) is desposited to overlie the substrate (12) and a fill material (20, 36) which can be dielectric material or a conductive material, is deposited to overlie the BN polish stop (18) and the recessed regions of the substrate.

Abstract: An LDD transistor is formed by using a process which insures that a layer of gate oxide is not inadvertently etched into and is not ruptured by static electrical charges. At least two thicknesses of gate electrode material of varying doping levels are formed over a layer of gate oxide which is above a semiconductor substrate. A chemical etch is utilized wherein by monitoring a ratio of chemical product and chemical reactant of the chemical etch reactions, specific endpoints in the etching of the gate electrode material can be easily detected. A small layer of gate electrode material is allowed to remain over the gate oxide layer during ion implanting and the formation and removal of gate sidewall spacers used in fabricating an LDD transistor. After formation of most of the LDD transistor, the remaining protective thickness of gate electrode material is removed and the exposed gate oxide layer is exposed to a final oxidizing anneal step.

Abstract: A semiconductor process is provided for the formation of a very low resistance contact. After a straight wall contact is formed conventionally above a silicon substrate, a blanket metal barrier layer is deposited. A plurality of planar polysilicon layers are deposited above the metal barrier layer. The polysilicon layers have varying doping levels and are etched away. A byproduct gas of the etch reaction is monitored and the transition between polysilicon layers can be accurately noted. In this way, a layer of doped polysilicon is left above the metal barrier in the contact region. Metal may then be patterned over the entire structure to provide a low resistance reliable contact.

Abstract: A process is disclosed for fabricating LDD CMOS structures having a reduced mask count and improved manufacturability. In one embodiment of the invention a CMOS structure is formed having gate insulators overlying N and P type surface regions. Gate electrodes are formed on each of the surface regions and a spacer forming material is deposited over the electrodes and the surface regions. The spacer material is anisotropically etched from one of the surface regions to form spacers at the edge of the first gate electrode while retaining the spacer forming material over the second surface region. Source and drain regions of the first MOS transistor are implanted using the spacers as an implantation mask. The spacers are removed and a lightly doped source and drain is implanted using the gate electrode as a mask. The implanted source and drain regions are oxidized using the remaining spacer forming material as an oxidation mask to prevent oxidation of the second surface region.