Browse Prior Art Database

Reflowed Boron Oxide in Integrated Circuit Processing

IP.com Disclosure Number: IPCOM000100031D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Luce, S: AUTHOR [+2]

Abstract

A thin layer of boron oxide (B203) is applied by chemical vapor deposition (CVD) over tungsten (W), reflowed, and then reactive ion etched (RIE) to create a smooth W surface. A reflowed layer of B203 is also used to retain a nucleating layer, e.g., titanium (Ti), in contact holes for subsequent selective deposition of W.

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Reflowed Boron Oxide in Integrated Circuit Processing

       A thin layer of boron oxide (B203) is applied by chemical
vapor deposition (CVD) over tungsten (W), reflowed, and then reactive
ion etched (RIE) to create a smooth W surface. A reflowed layer of
B203 is also used to retain a nucleating layer, e.g., titanium (Ti),
in contact holes for subsequent selective deposition of W.

      Roughness of CVD W film surfaces causing difficulty in defining
very small wiring features may be made smoother by applying and
reflowing B203, then etching all of the oxide off using an RIE etch
process which removes the oxide and W at the same rate.

      The figures are used to aid in describing a second useful
application for reflowed B203 in integrated circuit processing.
Referring to Fig. 1, a nucleating layer, e.g., Ti 10, is conformally
deposited on all exposed surfaces, e.g., insulator 12 and contact
region of substrate 14.

      Referring to Fig. 2, B203 layer 16 is deposited over nucleating
layer 10 and reflowed.

      Referring to Fig. 3, RIE etching is used to remove all of
layers 16 and 10 from uppermost surfaces, as shown.

      Referring to Fig. 4, selective etching is used to remove all
remaining B203 16 and then selective W 18 is deposited to complete a
W stud contact.

      Note that processing such as CVD and RIE may be performed
serially within a single, multi-station tool without removal to
normal air environment.