Semiconductor integrated circuit device and manufacturing method thereof
A manufacturing process for a semiconductor integrated circuit device prevents occurrence of reaction between metal wiring and a boron-doped silicon plug over it in heat treatment for a MOS transistor to be formed over them and reduces the possibility of rise in contact resistance. Metal boride is formed on an exposed metal surface in the bottom of an opening made in an interlayer insulating film over the metal wiring. In order to facilitate formation of such metal boride, metal oxide remaining on the metal surface is removed with an aqueous ammonia solution. The metal surface is irradiated with high energy ultraviolet light in order to remove organic matter remaining in the opening and facilitate removal of the metal oxide with the aqueous ammonia solution.
1. A semiconductor integrated circuit device comprising:
tungsten wiring which is formed on a semiconductor substrate;
a silicon-containing insulating film formed on the tungsten wiring;
an opening which is made by removing a given area of the insulating film and boring it until the tungsten wiring is reached; and
a plug of silicon doped with N-type or P-type impurities, buried in the opening,
wherein a metal compound containing the tungsten and boron is formed on the surface of the tungsten present in the bottom of the opening.
2. A semiconductor integrated circuit device comprising:
tungsten wiring which is formed on a semiconductor substrate;
a silicon-containing insulating film formed on the tungsten wiring; and
a plug of silicon doped with N-type or P-type impurities, formed on a given area of the tungsten wiring,
wherein a metal compound containing the tungsten and boron is formed on the surface of the tungsten.
3. The semiconductor integrated circuit device according to claim 1 , wherein the metal compound contains a metal element as an ingredient of the tungsten wiring and silicon.
4. The semiconductor integrated circuit device according to claim 1 ,
wherein the plug consists of a silicon layer doped with N-type or P-type impurities, buried in the opening; and
wherein the silicon layer remains inside the opening or inside the opening and on the insulating film surface around the opening.
5. The semiconductor integrated circuit device according to claim 1 ,
wherein the plug consists of a silicon layer doped with N-type or P-type impurities, buried in the opening; and
wherein one end of the plug is in touch with a metal compound of the tungsten and boron, formed on the surface of the tungsten present in the bottom of the opening, and at its other end, the silicon layer remains inside the opening or inside the opening and on the insulating film surface around the opening.
6. The semiconductor integrated circuit device according to claim 1 , wherein a silicon layer doped with N-type or P-type impurities which is formed on the insulating film with one end of it connected with the plug is used as a source or drain of a MOS transistor.
7. The semiconductor integrated circuit device according to claim 1 , having a vertically multi-layered MOS transistor on the semiconductor substrate,
wherein a first silicon layer doped with N-type or P-type impurities of a first concentration which is formed on the insulating film with one end of it connected with the plug is used as a source or drain of a MOS transistor,
wherein a second silicon layer is laid over the first silicon layer and used as a channel region, the second silicon layer containing virtually no such impurities as contained in the first silicon layer or containing impurities of the type opposite to the type of the impurities contained in the first silicon layer as effective impurities, and
wherein a third silicon layer doped with N-type or P-type impurities of the first concentration is laid over the second silicon layer and used as a drain or source.
8. The semiconductor integrated circuit device according to claim 1 , having a MOS transistor,
wherein a first silicon layer doped with N-type or P-type impurities of a first concentration which lies on the insulating film with one end of it connected with the plug, parallel to the semiconductor substrate, is used as a source or drain of a MOS transistor,
wherein a second silicon layer adjacent to the first silicon layer is used as a channel, the second silicon layer containing virtually no such impurities as contained in the first silicon layer or containing impurities of the type opposite to the type of the impurities contained in the first silicon layer as effective impurities, and
wherein a third silicon layer adjacent to the second silicon layer and doped with N-type or P-type impurities of the first concentration is used as a drain or source.
9. The semiconductor integrated circuit device according to claim 1 , wherein the P-type impurities are boron.
10. The semiconductor integrated circuit device according to claim 1 , wherein the N-type impurities are phosphorus or arsenic.