Patents by Inventor Kwong Tsai, Jr.

Kwong Tsai, Jr. has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5893734
    Abstract: DRAM devices are made having self-aligned tungsten landing plug contacts to gate electrodes for capacitor-under-bit line (CUB) for reduced aspect ratio contact openings. A planar insulating layer is formed, and openings for bit line contacts, node contacts, and contacts on the chip periphery are concurrently etched for metal landing plugs. A TiN/Ti/N.sup.+ polysilicon multilayer is deposited and annealed to form low contact resistance to the substrate A tungsten (W) layer is then deposited and etched back to form W landing plug contacts in the contact openings, which reduce the aspect ratio for the multilevel contacts. A Si.sub.3 N.sub.4 etch-stop layer and a BPSG are deposited and planarized. Capacitor openings are etched in the BPSG aligned over the node contacts. A conformal conducting layer and a planarized polymer are deposited and polished back to complete the bottom electrodes in the capacitor openings.
    Type: Grant
    Filed: September 14, 1998
    Date of Patent: April 13, 1999
    Assignee: Vanguard International Semiconductor Corporation
    Inventors: Erik S. Jeng, Kwong Tsai, Jr.