Advanced Micro Devices Corporation

Other

Darrell M Erb

Steven C Avanzino

Robin W Cheung

Fei Wang

Paul Raymond Besser

Rich K Klein

Christy Mei-Chu Woo

Ming-Ren Lin

Subhash Gupta

Scott D Luning

Amit P Marathe

Kai Yang

Richard K Klein

Bryan M Tracy

Bhanwar Singh

Sergey D Lopatin

Asim A Selcuk

Susan H Chen

Diana M Schonauer

Carmen L Morales

Jerry Cheng

John Sanchez

Pervaiz Sultan

Ramkumar Subramanian

Zoran Krivokapic

Calvin T Gabriel

Richard J Huang

Suzette Keefe Pangrle

Todd P Lukanc

Pin-Chin Connie Wang

Lynne A Okada

Connie Pin-Chin Wang

Ercan Adem

Farrokh Kia Omid-Zohoor

Rajat Rakkhit

Alline F Myers

Pau-ling Chen

Electromigration and stress migration of Cu interconnects are significantly reduced by forming a composite capping layer comprising a layer of tantalum nitride on the upper surface of the inlaid Cu and a layer of &#x3b1;-Ta on the titanium nitride layer. Embodiments include forming a recess in an upper surface of an upper surface of Cu inlaid in a dielectric layer, depositing a layer of titanium nitride of a thickness of 20 &#x212b; to 100 &#x212b; and then depositing a layer of &#x3b1;-Ta at a thickness of 200 &#x212b; to 500 &#x212b;.

Composite tantalum nitride/tantalum copper capping layer

Systems and methods are disclosed that facilitate predicting electromigration (EM) reliability in semiconductor wafers via decoupling intrinsic and extrinsic components of EM reliability. Electrical cross-sections of wafer test lines can be determined and individual currents can be forced through the test lines to force a constant current density across a test wafer. An EM reliability test can be performed to determine a purely intrinsic component of EM reliability. A single current can then be applied to all test lines and a second EM reliability test can be performed to determine total EM reliability. Standard deviations, or sigma, of failure distributions can be derived for each EM test. Intrinsic sigma can be subtracted from total sigma to yield an extrinsic sigma associated with process variation in wafer fabrication. Sigmas can then be utilized to predict EM reliability when process variations are adjusted, without application of a damaging package-level EM test.

Predicting EM reliability by decoupling extrinsic and intrinsic sigma

Damascene processing is implemented with dielectric barrier films () for improved step coverage and reduced contact resistance. Embodiments include the use of two different dielectric films () to avoid misalignment problems. Embodiments further include dual damascene (A,B) processing using Cu metallization ().

Stabilizing fluorine etching of low-k materials

The electromigration and stress migration of Cu interconnects is significantly reduced by forming a composite capping layer comprising a layer of &#x3b2;-Ta on the upper surface of the inlaid Cu, a layer of tantalum nitride on the &#x3b2;-Ta layer and a layer of &#x3b1;-Ta on the tantalum nitride layer. Embodiments include forming a recess in an upper surface of Cu inlaid in a dielectric layer, depositing a layer of &#x3b2;-Ta at a thickness of 25 &#x212b; to 40 &#x212b;, depositing a layer of tantalum nitride at a thickness of 20 &#x212b; to 100 &#x212b; and then depositing a layer of &#x3b1;-Ta at a thickness of 200 &#x212b; to 500 &#x212b;. Embodiments further include forming an overlying dielectric layer, forming an opening therein, e.g., a via opening or a dual damascene opening, lining the opening with &#x3b1;-Ta, and filling the opening with Cu in electrical contact with the underlying inlaid Cu.

Composite tantalum capped inlaid copper with reduced electromigration and reduced stress migration

High reliable copper interconnects are formed with copper or a low resistivity copper alloy filling relatively narrow openings and partially filling relatively wider openings and a copper alloy having improved electromigration resistance selectively deposited in the relatively wider openings. The filled openings are recessed and a metal capping layer deposited followed by CMP. The metal capping layer prevents diffusion along the copper-capping layer interface while the copper alloy filling the relatively wider openings impedes electromigration along the grain boundaries.

Copper interconnects with metal capping layer and selective copper alloys

The reliability and performance of planarized metallization patterns in an electrical device, for example copper, inlaid in the surface of a layer of dielectric material overlying a semiconductor wafer substrate, are enhanced by a method for reliably depositing a barrier layer selective to the metallization patterns. The method comprises forming a sacrificial dielectric layer above a substrate. Metallization patterns are formed in the sacrificial dielectric layer. The barrier layer is selectively deposited on the metallization patterns. Portions of the barrier material undesirably deposited on the sacrificial dielectric layer are removed by removing the sacrificial dielectric layer, thus preventing bridging of adjacent metallization features by the barrier layer portions. An interlevel dielectric layer is then formed in place of the sacrificial dielectric layer. The selectively deposited barrier layer advantageously reduces parasitic capacitance between metallization features in comparison to a conventional blanket-deposited silicon nitride barrier layer.

Method of forming a selective barrier layer using a sacrificial layer

For filling an interconnect opening within a porous dielectric material, a diffusion barrier material is deposited onto at least one sidewall of the interconnect opening. A thickness of the diffusion barrier material is equal to or greater than a radius of a pore opened at the sidewall to substantially fill the opened pore. The thickness of the diffusion barrier material is equal to or greater than a mean radius of pores opened at the sidewall to substantially fill a majority of the opened pores. Or, the thickness of the diffusion barrier material is equal to or greater than a radius of a largest pore opened at the sidewall to substantially fill all opened pores. The interconnect opening is then filled with a conductive fill material.

Continuous barrier for interconnect structure formed in porous dielectric material with minimized electromigration

The present invention provides for improved alignment of an opening in a lower dielectric layer with an opening in an upper dielectric layer. This improved alignment is beneficial as it improves the functionality of devices with dual damascene material arrangements, as normal misalignments do not deem the devices inferior or non-functional. Further, the present invention is beneficial as it allows for a designer, such as a microprocessor designer, to depend on more predictable conductive characteristics of contacts between a first conductive region and a second conductive region.

Self-aligned conductive plugs in a semiconductor device

A conductive diffusion barrier surrounding a conductive element is enhanced by an implanted diffusion barrier enhancing material. The enhancing material is implanted using a low energy implant at an angle to the substrate, such that the portion of the diffusion barrier at the bottom of the conductive element is protected during implantation. This prevents the increased resistivity caused by the enhancing material from affecting the conductive path between the conductive element and another conductive element. The diffusion barrier is preferably titanium nitride (TiN) and the enhancing material is preferably silicon (Si).

Diffusion barrier and method for its production

The reliability and electromigration life-time of planarized metallization features, e.g., copper, inlaid in the surface of a layer of dielectric material, are enhanced by a chemical vapor deposition process for depositing a passivation layer over the metallization patterns which comprises maintaining on the upper surfaces of the metallization features, at or below a first temperature, an inhibiting film previously deposited thereon. The inhibiting film substantially inhibits oxide layer formation on the surface of the metallization features below the first temperature. Passivation layer deposition occurs at a second temperature higher than the first temperature such that the time interval between removal of the inhibiting film and formation of the passivation layer is short enough to substantially inhibit the formation of oxides on the surface of the metal feature.

Low temperature dielectric deposition to improve copper electromigration performance

A Cu interconnect, e.g.; a dual damascene structure, is formed with improved electromigration resistance and increased via chain yield by depositing a barrier layer in an opening by CVD, depositing a flash layer of &agr;-Ta by PVD, at a thickness less than 30 &angst;, on the bottom of the barrier layer, depositing a seedlayer and then filling the opening with Cu. Embodiments include depositing a thin &agr;-Ta layer, as at a thickness less than 10 &angst;, and/or as discontinuous regions of clusters of atoms on sides of the opening.

Copper interconnect with improved barrier layer

The electromigration resistance of planarized metallization patterns, for example copper, inlaid in the surface of a layer of dielectric material, is enhanced by a process comprising blanket-depositing on the planarized, upper surfaces of the metallization features and the dielectric layer at least one alloying layer comprising at least one alloying element for the metal of the features, and diffusing the at least one alloying element within the metallization features to effect alloying therewith. The at least one alloying element diffused within the metallization features, under conditions wherein an oxide layer forms on the surface of the metallization features, forms a stable oxide layer on the surface of the metallization features. The stable oxide layer reduces electromigration from the metallization features along the oxide layer.

Use of an alloying element to form a stable oxide layer on the surface of metal features

The reliability and electromigration resistance of planarized, in-laid metallization patterns, e.g., of copper, are enhanced by a process comprising selectively depositing on the planarized, upper surfaces of the metallization features at least one thin layer with at least one alloying element for the metal of the feature, and then uniformly diffusing at least a minimum amount of the at least one alloying element of the at least one thin layer for a predetermined minimum depth below the upper surface of the features to effect alloying therewith. The alloyed portions of the metallization features advantageously reduce electromigration therefrom. Planarization, as by CMP, may be performed subsequent to diffusion/alloying to remove any remaining elevated, alloyed or unalloyed portions of the at least one thin layer. The invention finds particular utility in &ldquo;back-end&rdquo; metallization processing of high-density integrated circuit semiconductor devices having sub-micron dimensioned metallization features.

Selective deposition process for allowing damascene-type Cu interconnect lines

An integrated circuit and manufacturing method therefore is provided having a semiconductor substrate with a semiconductor device. A device dielectric layer is formed on the semiconductor substrate, and a channel dielectric layer formed on the device dielectric layer has an opening formed therein. A barrier layer lines the channel opening and a conductor core fills the opening over the barrier layer. Before planarization of the conductor core and the barrier layer, an anneal of the semiconductor substrate is performed at high temperatures of 400&deg; C. and above to stimulate grain growth. After planarization, subsequent high temperature deposition of passivating or capping layers will not cause grain growth and hillocks will be suppressed.

Anneal hillock suppression method in integrated circuit interconnects

The dimensional accuracy of trenches and, hence, the width of metal lines, in damascene interconnection structures is improved by employing silicon carbide as a capping layer/BARC on an underlying metal feature, e.g., Cu. Embodiments include via first-trench last dual damascene techniques employing a silicon carbide capping layer/BARC having an extinction coefficient (k) of about &minus;0.2 to about &minus;0.5, without the need for a middle etch stop layer, thereby improving efficiency by reducing the number of processing steps.

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Los Altos, CA, United States of America

Darrell M Erb