Appeal No. 2001-2203
Application No. 09/007,949
concentration gradient of the selected alloying element at the
interface of the two metal layers.
Claim 1 is illustrative of the invention and reads as follows:
1. A method for forming a contact electrically connected to a
metal line, the method comprising the steps of:
forming an insulation layer situated on a semiconductor
substrate;
forming a contact hole in the insulation layer to expose a
contact surface on said semiconductor substrate;
forming a first metal layer over the insulation layer, said
first metal layer substantially filling the contact hole;
forming a second metal layer having a substantially planar top
surface upon a top planar surface of said insulation layer and upon
a top surface of said first metal layer, said second metal layer
being in electrical contact with said contact surface on said
semiconductor substrate;
heating said semicoductor substrate sufficiently to cause a
selected alloying element from one of said first and second metal
layers to diffuse into the other of said first and second metal
layers, whereby there is a substantially continuous concentration
diffusion gradient of said selected alloying element between said
first metal layer and said second metal layer.
The Examiner relies on the following prior art:
Yu et al. (Yu) 5,244,534 Sep. 14, 1993
Lee et al. (Lee) 5,355,020 Oct. 11, 1994
Mathews et al. (Mathews) 5,580,821 Dec. 03, 1996
Wilson et al. (Wilson) GB 2 169 446 A Jul. 09, 1986
Claims 1-26, all of the appealed claims, stand finally
rejected under 35 U.S.C. § 103(a). As evidence of obviousness, the
2
Page: Previous 1 2 3 4 5 6 7 8 9 10 Next
Last modified: November 3, 2007