US 6,207,566 B1Granted

Method for forming a metal plug on a semiconductor wafer

AssigneeUnited Microelectronics Corp.

InventorChing-I Chang

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Abstract

The present invention provides a method for forming a metal plug on a semiconductor wafer. The semiconductor wafer comprises a substrate, and at least one first conductive layer installed in a predetermined area on the surface of the substrate. The method involves first forming a dielectric layer with a thickness of less than 1000 Angstroms (Å) on the surface of the substrate, then forming a hole above the first conductive layer which passes through the dielectric layer and reaches the first conductive layer. A second conductive layer is uniformly formed over the dielectric layer and the hole. A mask is formed on the surface of the second conductive layer which is above the hole of the dielectric layer to define the position of a metal plug. Finally, a second dry etching process removes the second conductive layer which is not covered by the mask, the remaining second conductive layer under the mask being the metal plug, and the mask is then completely removed.

Claims6

Dependent claims

A method for forming a via plug on a semiconductor wafer, the semiconductor wafer comprising a first conductive layer, the method comprising the following steps:

forming a dielectric layer with a thickness less than 1000 angstrom (Å) on the surface of the first conductive layer;
forming a plurality of first holes and second holes above the first conductive layer which pass through the dielectric layer and reach the first conductive layer wherein the first holes define the positions of the metal plugs on the first conductive layer and the second holes define the pattern of a metal conductive line;
forming a second conductive layer uniformly over the dielectric layer which fills the holes;
forming a mask on the surface of the second conductive layer above each of the first holes;
performing a second dry etching process to remove the second conductive layer which is not covered by the masks and remove the first conductive layer which is not covered by the masks or the dielectric layer, the remaining second conductive layer under each of the masks being the via plug, the remaining first conductive layer under the masks and the dielectric layer being the metal conductive line;
and
removing the mask completely.

4 more elements

Dependencies are inferred from the claim text.