Method for fabricating thermally stable contacts with a diffusion barrier formed at high temperatures
AssigneeTexas Instruments Incorporated
InventorsJiong-Ping Lu, Chih-Chen Cho
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Abstract
In order to provide a thermally stable diffusion barrier for a contact, a layer of titanium is formed on the patterned substrate. A layer of tungsten nitride is formed on the titanium layer. After an annealing step, an interfacial layer and a layer of titanium nitride are formed between the substrate and a tungsten layer. These layers provide a diffusion barrier which is more thermally stable than a titanium nitride layer applied directly on the substrate and permits the formation of a contact structures that can withstand subsequent high temperature steps.
Claims13
A method of forming a diffusion barrier layer for a contact structure, said method comprising the steps of:
- forming a layer of titanium on a patterned substrate;
- forming a layer of tungsten nitride on said titanium layer;
- annealing said layers along with said substrate to form a titanium nitride layer and a tungsten layer.
A method for forming a contract structure, said method comprising the steps of:
- forming a titanium layer on a substrate;
- forming a tungsten nitride layer on said titanium layer,
- forming a tungsten layer on said tungsten nitride layer;
- and
- annealing the structure resulting from a formation of these layers to form a titanium nitride layer and a tungsten layer.
Dependencies are inferred from the claim text.