United Microelectronics Corp.

Liang-Chih Lin

Water Lur

Cheng-Han Huang

Shih-Chanh Chang

A method of metallization using a tungsten plug is described. A contact hole is opened to the semiconductor substrate through an insulating layer covering semiconductor structures in and on the semiconductor substrate. A glue layer is deposited conformally over the surface of the insulating layer and within the contact opening. A tungsten plug is formed within the contact opening. The glue layer is removed except for portions of the glue layer underneath the tungsten plug and on the lower sides of the tungsten plug. Ditches are left on the upper sides of the tungsten plug where the glue layer has been removed. The ditches around the tungsten plug are filled with a dielectric material. A second metallization is deposited and patterned. The patterned second metallization does not extend over one side portion of the tungsten plug; that is, there is no dog-bone formation. There is no junction damage through the side portion of the tungsten plug not covered by the second metallization because the dielectric material filling the ditches protects the glue layer from being etched away. In a second embodiment of the invention, after the contact hole is opened, the insulating layer is reflowed forming an overhang around the contact hole. A glue layer is deposited conformally over the surface of the insulating layer and within the contact opening. A tungsten plug is formed within the contact opening.

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Hsin-chu, Taiwan

Liang-Chih Lin