Abstract: A semiconductor substrate including a first region, a second region larger than the first region and an isolation region is provided. A mask layer is selectively formed on the first and second regions. A trench is formed on the isolation region. A first isolation material is deposited on the entire surface so that the trench is filled with the first material and the first material covers the first and second regions. The first material is subjected to a chemical mechanical polish so that the mask layer formed on the first region is exposed while the mask layer formed on the second region is still covered by the first material. Then, a second insulation material is deposited on the exposed mask layer and the first material. Finally, the second material is subjected to the chemical mechanical polish so that mask layer formed on the first and second regions is substantially exposed.

Abstract: A semiconductor element has an upper wiring layer and a lower wiring layer. The upper and lower wiring layers communicate with each other via a via-hole. The via-hole is filled with W. Before W is filled in the via-hole by a CVD process to connect the lower wiring layer to the upper wiring layer, a cleaning gas is supplied into the via-hole to remove particular substances, which would otherwise result in high resistance. Subsequent to the cleaning step, the W portion is formed in the via-hole. Since the high resistance substances are removed from the via-hole before the formation of the W portion, the semiconductor element (or the via-hole) has a low resistance and high reliability.

Abstract: A semiconductor element has an upper wiring layer and a lower wiring layer. These layers communicate with each other via a via-hole. The via-hole is filled with W. Before W is filled in the via-hole by a CVD process to connect the lower wiring layer to the upper wiring layer, a cleaning gas is supplied into the via-hole to remove particular substances, which would otherwise result in high resistance. Subsequent to the cleaning step, the W portion is formed in the via-hole. Since the high resistance substances are removed from the via-hole before the formation of the W portion, the semiconductor element (or the via-hole) has a low resistance and high reliability.

Abstract: A method of manufacturing a semiconductor device comprises providing a semiconductor substrate that includes a first active region having a first area, a second active region having a second area that is larger than the first area and an isolation region. Then, a mask layer is selectively formed on the first and second active regions. A trench is formed on the isolation region of the substrate. A first isolation material is deposited on the trench and the mask layer so that the trench is filled with the first material and the first material covers the first and second active regions. The first material is subjected to a chemical mechanical polish so that the mask layer formed on the first active region is exposed while the mask layer formed on the second active region is still covered by the first material. Then, a second insulation material is deposited on the exposed mask layer and the first material.