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US 2019/0319088 A1Published application
Low resistance metal-insulator-metal capacitor electrode
AssigneeInternational Business Machines Corporation
InventorsJoseph F. Maniscalco, Koichi Motoyama, Oscar van der Straten, Chih-Chao Yang
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Abstract
Integrated circuits including metal-insulator-metal capacitors (MIMCAPs) generally include a diffusion barrier layer on the top and bottom surfaces of the electrode and a self-formed oxide layer on sidewalls of the electrode. The diffusion barrier layers and the self-formed oxide layers on the sidewalls of the electrode prevent diffusion of the metal defining the electrode into the interlayer dielectric. Also described are processes for fabricating the MIMCAPs.
Claims20
A metal-insulator-metal capacitor comprising:
- a copper alloy electrode comprising an alloying element and a barrier metal layer on the top and bottom surfaces thereof, wherein the barrier metal layer comprises titanium, titanium nitride, tantalum, tantalum nitride, tungsten, tungsten nitride, ruthenium, ruthenium nitride, cobalt, cobalt nitride, or combination thereof;
- a dielectric material including oxygen and at least one element selected from the group consisting of Si, C, and F, wherein the dielectric material completely covers and is in contact with the sidewalls of the copper alloy electrode;
- and
- a self-formed metal oxide layer containing a reaction product between the alloying element and the dielectric material on the sidewalls of the copper alloy.
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(canceled)
An integrated circuit comprising:
- at least one layer comprising one or more metal-insulator-metal capacitors formed in an interlayer dielectric, each one of the one or more metal-insulator-metal capacitors comprising:
- a top electrode comprising a copper alloy including an alloying element and a copper diffusion barrier layer on the top and bottom surfaces thereof, wherein the copper diffusion barrier layer comprises titanium, titanium nitride, tantalum, tantalum nitride, tungsten, tungsten nitride, ruthenium, ruthenium nitride, cobalt, cobalt nitride, or combination thereof;
- a bottom electrode comprising a copper alloy including an alloying element and the copper diffusion barrier layer on the top and bottom surfaces thereof;
- and
- a dielectric layer disposed between the top and bottom electrodes including oxygen and at least one element selected from the group consisting of Si, C, and F, wherein the dielectric material completely covers and is in contact with the sidewalls of the copper alloy electrode;
- and a self-formed metal oxide layer containing a reaction product between the alloying element and the dielectric material on the sidewalls of the copper alloy;
- and
- metal interconnects formed in the interlayer dielectric to the top and bottom electrodes, wherein the interlayer dielectric contains oxygen.
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A method for fabricating a metal-insulator-metal capacitor in an integrated circuit, the method comprising:
- depositing a plurality of layers onto a substrate, the plurality of layers comprising, in sequence, a first barrier layer, a bottom metal electrode layer comprising a copper alloy including an alloying element, a second barrier layer, a dielectric layer, third barrier layer, a top metal electrode layer comprising the copper alloy, a fourth barrier layer wherein the first, second, third and fourth barrier layers on the respective bottom electrode layer and the top metal electrode layer comprise titanium, titanium nitride, tantalum, tantalum nitride, tungsten, tungsten nitride, ruthenium, ruthenium nitride, cobalt, cobalt nitride, or combination thereof, and wherein the dielectric layer is formed of a material including oxygen and at least one element selected from the group consisting of Si, C, and F, wherein the dielectric layer completely covers and is in contact with the sidewalls of the copper alloy electrode,
- patterning the third barrier layer, the top metal electrode layer, and the fourth barrier layer to define a top electrode;
- patterning the dielectric layer such that the dielectric layer has a width equal to a width of the top electrode and underlies the top electrode;
- patterning the second barrier layer, the bottom metal electrode layer, and the first barrier layer to define a bottom electrode;
- depositing in interlayer dielectric on the top and bottom electrodes, wherein the interlayer dielectric contains oxygen;
- reacting the alloying element in the copper alloy of the top and bottom electrodes with at least the oxygen in the interlayer dielectric to form a reaction product therebetween containing a metal oxide on sidewalls of the top and bottom electrodes;
- and
- patterning the interlayer dielectric to form metal interconnects to the top and bottom electrodes, wherein the top and bottom electrodes and the dielectric layer therebetween define the metal-insulator-metal capacitor.
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Dependencies are inferred from the claim text.