Cost effective method of forming embedded DRAM capacitor
View Patent ↗A high capacitance embedded metal interconnect capacitor and associated fabrication processes are disclosed for using a directional barrier metal formation sequence in a dual damascene copper process to form multi-layer stacked copper interconnect structure having reduced barrier metal layer formation at the bottom of each via hole so that the multi-layer stacked copper interconnect structure may be readily removed and replaced with high capacitance MIM capacitor layers.
1. An integrated circuit device comprising:
a semiconductor substrate comprising one or more active circuits and at least a first conductive contact structure; and
a stacked interconnect structure formed on the semiconductor substrate with multiple interconnect levels, each interconnect level comprising:
a metal-based damascene interconnect structure comprising a first directional diffusion barrier liner layer located on a sidewall of a first opening in one or more patterned dielectric layers; and
a damascene capacitor structure comprising a second directional diffusion barrier liner layer located on a sidewall of a second opening in the one or more patterned dielectric layers and a plurality of capacitor layers formed on the directional diffusion barrier liner layer,
where the metal-based damascene interconnect structures in each interconnect level are aligned for electrical connection to the one or more active circuits, and where the damascene capacitor structures in each interconnect level are aligned to form a single capacitor having a first capacitor plate electrically connected to the first conductive contact structure.
2. The integrated circuit device of claim 1 , where the semiconductor substrate comprises a semiconductor on insulator (SOI) substrate or bulk semiconductor substrate.
3. The integrated circuit device of claim 1 , where the one or more active circuits comprises an embedded dynamic random access memory circuit.
4. The integrated circuit device of claim 1 , where the first and second directional diffusion barrier liner layers each comprise one or more sputter-deposited layers of TaN, Ta, TiN, and/or WN which are applied with bias condition to prevent formation of the sputter-deposited layers on horizontal surfaces.
5. The integrated circuit device of claim 1 , where the metal-based damascene interconnect structure in each interconnect level comprises electro-plated copper formed on the first directional diffusion barrier liner layer.
6. The integrated circuit device of claim 1 , where the plurality of capacitor layers in each damascene capacitor structure occupies space where a metal-containing damascene interconnect structure was formed prior to fabrication of an adjacent interconnect level.
7. The integrated circuit device of claim 1 , where the plurality of capacitor layers in each damascene capacitor structure comprises a conductive bottom plate electrode layer, a high-k capacitor dielectric layer formed on the conductive bottom plate electrode layer, and a conductive top plate electrode layer formed on the high-k capacitor dielectric layer.
8. The integrated circuit device of claim 7 , where the conductive bottom plate electrode layer in each damascene capacitor structure is separated from the one or more patterned dielectric layers by at least the second directional diffusion barrier liner layer.
9. An integrated circuit DRAM circuit, comprising:
a substrate in which is formed at least a portion of a dynamic random access memory (DRAM) bit cell circuitry;
a multilevel interconnect stack on the substrate comprising one or more first metal-containing interconnect features, each at least partially separated from dielectric material of the multilevel interconnect stack by a resputtered diffusion barrier sidewall liner layer; and
a capacitor formed at least in part in the multilevel interconnect stack comprising a bottom electrode layer, a dielectric layer, and a top electrode layer, wherein the bottom electrode layer is at least partially separated from dielectric material of the multilevel interconnect stack by a resputtered diffusion barrier sidewall liner layer.
10. The integrated circuit DRAM circuit of claim 9 , where the resputtered diffusion barrier sidewall liner layer comprises sputter-deposited layers of TaN, Ta, TiN, and/or WN which are applied with bias condition to prevent formation of the sputter-deposited layers on horizontal surfaces.
11. The integrated circuit DRAM circuit of claim 9 , where the multilevel interconnect stack comprises a metal-based damascene interconnect structure in each interconnect stack level comprising electro-plated copper formed on the resputtered diffusion barrier sidewall liner layer.
12. The integrated circuit DRAM circuit of claim 9 , where the capacitor occupies a trench opening in the multilevel interconnect stack formed by etching one or more second metal-containing interconnect features formed in the multilevel interconnect stack to be at least partially separated from dielectric material of the multilevel interconnect stack by a resputtered diffusion barrier sidewall liner layer.