Hybrid via interconnect structure

A hybrid via interconnect structure includes a first metal filling at least partially surrounded by a first barrier metal layer, a second metal filling at least partially surrounded by a second barrier metal layer, and a hybrid via formed between the first metal filling and the second metal filling. The hybrid via provides an electrical connection between the first metal filling and the second metal filling and is formed of a different material than the first metal filling, the second metal filling, the first barrier metal layer, and the second barrier metal layer. The hybrid via interconnect structure can be formed during the back end of line (BEOL) portion of an integrated circuit (IC) fabrication process to provide reduced interconnect resistance and improved ease of fabrication.

BACKGROUND

The present disclosure generally relates to semiconductor devices and methods for forming circuits including semiconductor devices. More particularly, the present disclosure relates to interconnect structures formed during the integrated circuit fabrication process.

Semiconductor devices are used in a wide variety of electronics, and improvements regarding both production and performance of semiconductor devices are generally desired. As the size of these devices continues to decrease, challenges in creating high performance and feasible interconnect structures can arise.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows can include embodiments in which the first and second features are formed in direct contact, and can also include embodiments in which additional features can be formed between the first and second features, such that the first and second features can not be in direct contact. In addition, the present disclosure can repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

The present disclosure provides various embodiments of a hybrid via interconnect structure that can be used to provide improved interconnect structures within an integrated circuit. The hybrid via interconnect structure includes a hybrid via that generally provides an electrical connection between two metals such as two copper interconnects. The hybrid via can be formed of a variety of materials including metals, alloys, and other conductive materials. The hybrid via interconnect structure can be formed using a single damascene process, a dual damascene process, a reactive ion etching process, and other suitable processes. The hybrid via interconnect structure can provide advantages in terms of reduced contact and interconnect resistance as well as improved ease and efficiency of fabrication.

FIGS.1-10illustrate cross sections of various embodiments of a hybrid via interconnect structure100that is formed using a single damascene process. Hybrid via interconnect structure100can generally be formed during the back end of line (BEOL) portion of an integrated circuit (IC) fabrication process. The BEOL portion of the IC fabrication process generally occurs after the front end of line (FEOL) portion of the IC fabrication process. In the FOEL portion, individual semiconductor devices (e.g. transistors, capacitors, resistors, etc.) are formed on a wafer (e.g. bulk silicon substrate) and separated into device regions using isolation structures (e.g. shallow trench isolation structures). In the BEOL portion, interconnections between individual devices and wiring on the wafer are formed. The BEOL portion can include formation of various contacts, metal layers, insulating layers, and bonding sites, for example.

Some previous approaches to forming interconnect structures during the BEOL portion of the IC fabrication process can suffer from high contact resistance. For example, when forming copper interconnects, the use of barrier metal layers to chemically isolate copper fillings from surrounding silicon material can lead to high contact resistance. This phenomenon can introduce propagation delays, increase power consumption, and cause other undesirable effects. Further, as the feature size of semiconductor devices decreases and the demand for smaller chips more generally increases, challenges with forming more traditional copper interconnects and other similar interconnect structures can arise. For example, difficulties in the filling process used to form copper interconnects can result in voids and other undesirable effects. These problems can arise when using various fabrication techniques including single damascene techniques, dual damascene techniques, reactive ion etching techniques, and other similar techniques.

As shown inFIG.1, hybrid via interconnect structure100includes a first metal filling122and a second metal filling124electrically connected by a hybrid via110. Metal filling122is surrounded by a barrier metal layer132and a capping layer160. The second metal filling124is surrounded by a barrier metal layer134. The first metal filling122can be completely surrounded by the combination of barrier metal layer132and capping layer160. The second metal filling124can be completely surrounded by barrier metal layer134(although this is not explicitly shown inFIG.1). These layers are adjacent to an insulating layer142and an insulating layer144that are separated by an etch stop layer150.

In some embodiments, both the metal filling122and metal filling124are copper interconnects. However, the metal filling122and metal filling124can be formed of other suitable materials (e.g. aluminum, etc.). The barrier metal layer132and barrier metal layer134chemically isolate the metal filling122and metal filling124, respectively, from surrounding materials such as silicon and other materials. For example, barrier metal layer132can prevent diffusion of metal filling122into insulating layer142. Barrier metal layer132and barrier metal layer134can be formed using materials such as tantalum, cobalt, ruthenium, and other suitable materials. Barrier metal layer132and barrier metal layer134are generally formed of a material that is effective in chemically isolating metal filling122and metal filling124while also being effective electrical conductors.

Insulating layer142and insulating layer144are generally dielectric materials with low electrical conductivity. For example, insulating layer142and insulating layer144can be formed of materials including silicon nitride, silicon oxide, and other suitable materials with a relatively high dielectric constants (high-k materials). Etch stop layer150can generally prevent over-etching such that structures below etch stop layer150(e.g. insulating layer142, capping layer160, etc.) are not damaged when structures above etch stop layer150are being etched. Further, etch stop layer150can facilitate improved precision during various etching processes. For example, a first etching process can be used until etch stop layer150is reached, and then a second etching process can be used to remove a portion of etch stop layer150that is exposed as a result of the first etching process. Etch stop layer150can be formed of materials such as silicon nitride, silicon carbide, silicon carbonitride, and other suitable materials. Capping layer160can generally be included to reduce electromigration within hybrid via interconnect structure100. Capping layer160can be formed using various materials such as silicon carbon nitride, silicon nitride, cobalt tungsten phosphide, copper alloys, and other suitable materials and combinations thereof.

Hybrid via110itself can be formed using various materials including metals (e.g. aluminum, copper, cobalt, nickel, tungsten, ruthenium, molybdenum, platinum, palladium, etc.), alloys (copper/zinc alloys, iron/cobalt alloys, molybdenum/tantalum alloys, etc.), other conductive materials (e.g. fullerenes, carbon nanotubes, molybdenum disulfide, etc.), and various other suitable materials and combinations thereof depending on the intended application. Hybrid via110is generally formed of different material(s) than metal filling122, metal filling124, barrier metal layer132, and barrier metal layer134are formed of. The use of different material(s) for hybrid via110can enable metallization for advanced nodes and can reduce contact resistance associated with hybrid via interconnect structure100overall, among other possible benefits.

Hybrid via interconnect structure100can generally provide reduced contact resistance and reduced interconnect resistance due to a variety of factors. For example, especially in wrapped via structures such as shown inFIGS.7-10(where metal filling122in contact with and wrapped around a portion of hybrid via110), contact resistance can be reduced due to a larger contact area between hybrid via110and metal filling122. Further, with the development of more advanced semiconductor nodes, various embodiments of hybrid via interconnect structure100can be easier and/or more efficient to produce depending on the intended application.

FIG.11Ais a flow diagram illustrating a process10for forming hybrid via interconnect structure100.FIGS.11B-11Jillustrate various steps of process10. Hybrid via interconnect structure100formed using process10can have lower contact and interconnect resistance and thereby improved performance when compared to some previous approaches. Further, process10can provide advantages in terms of ease and efficiency in the interconnect structure fabrication process in different applications when compared to some previous approaches. Process10is generally a single damascene process that involves formation of hybrid via110that electrically connects a metal filling122and a metal filling124. Hybrid via110is generally formed of a different material than metal filling122and metal filling124. Various adaptions of process10are contemplated such as described with respect toFIGS.2-10.

At a step11, a first interconnect structure is formed (FIG.11B). The first interconnect structure formed in step11includes metal filling122, barrier metal layer132, insulating layer142, etch stop layer150, and capping layer160. The first interconnect structure can be formed on top of a contact, such as a contact formed during a middle end of line (MEOL) portion of the integrated circuit fabrication process. For example, the first interconnect structure can be formed over a gate contact. Step11can include depositing insulating layer142on a contact surface, using lithography and etching techniques to form a trench within insulating layer142, depositing barrier metal layer132within the trench, forming a seed layer of metal filling122over barrier metal layer132(e.g. by using a physical vapor deposition process), filling the trench with additional metal filling material that is formed over the seed layer to form metal filling122, using chemical-mechanical planarization to remove excess material from metal filling122and barrier metal layer132, forming capping layer160over metal filling122and barrier metal layer132, and forming etch stop layer150over insulating layer142and capping layer160. The formation of metal filling122that occurs in step11can generally be characterized as a single damascene process, wherein the single trench is filled with metal filling122.

At a step12, an insulating layer is formed over the first interconnect structure (FIG.11C). The insulating layer formed in step12is insulating layer144. As illustrated inFIG.11C, insulating layer144is formed over etch stop layer150. Formation of insulating layer144in step12can include depositing material(s) with a high dielectric constant (high-k) such as silicon oxide and silicon nitride.

At a step13, a first trench is formed within the insulating layer (FIG.11D). As illustrated inFIG.11D, a trench172is formed within insulating layer144. Trench172can be formed using patterning and removal techniques such as suitable lithography and etching techniques. For example, a first etching process can be used to remove a portion of insulating layer144until etch stop layer150is reached. Then, a second etching process can be used to remove etching layer150until capping layer160is reached. As discussed below with respect toFIGS.2-10, trench172can also be formed such that it extends into and through capping layer160, and even into metal filling122as well. Trench172provides an opening to fill with material that becomes hybrid via110.

At a step14, a hybrid via is formed within the first trench (FIG.11E). That is, hybrid via110is formed within trench172by filling materials such as metals, alloys, and/or other conductive materials within trench172. As illustrated inFIG.11E, hybrid via110is formed such that a top surface of hybrid via110is flush or approximately flush with a top surface of insulating layer144. However, as discussed below with respect toFIGS.2-10, hybrid via110can also be formed such that it extends beyond the top surface of insulating layer144. Hybrid via110can be formed using processes such as physical vapor deposition, chemical vapor deposition, atomic layer deposition, electrochemical deposition, and other suitable processes. In some embodiments, the process temperature for the formation of hybrid via110ranges from about 20 degrees Celsius to 1000 degrees Celsius, however process temperatures outside of this range are also contemplated. Further, in some embodiments, hybrid via110ranges in height from about 5 angstroms to 100 microns, however heights outside of this range are also contemplated.

At a step15, additional insulating material is formed over the insulating layer and over the hybrid via (FIG.11F). The additional insulating material formed in step15is part of insulating layer144. Since process10is a single damascene process, the additional insulating material is deposited after formation of hybrid via110such that it can be patterned and filled to form a second interconnect structure as discussed in more detail below. Formation of the additional insulating material in step15can include depositing material(s) with a high dielectric constant (high-k) such as silicon oxide and silicon nitride.

At a step16, a second trench is formed within the additional insulating material (FIG.11G). As illustrated inFIG.11G, a trench174is formed within the additional insulating material formed as part of insulating layer144in step15. Trench174using patterning and removal techniques such as suitable lithography and etching techniques. Trench174provides an opening to fill with material that becomes metal filling124and barrier metal layer134, as discussed in detail below.

At a step17, a barrier metal layer and a seed layer of metal filling are formed within the second trench (FIG.11H). First, barrier metal layer134is deposited within trench174. Barrier metal layer134can be formed of materials such as tantalum, cobalt, ruthenium, and other similar materials that are effective in chemically isolating metal filling124while also being effective electrical conductors. Then, the seed layer of metal filling (e.g. copper material) is formed over barrier metal layer134. The seed layer of metal filling can provide improvements in the formation of metal filling124itself. For example, the seed layer can prevent formation of small air voids that can be formed between barrier metal layer134and metal filling124without the use of the seed layer. Barrier metal layer134and the seed layer of metal filling can be formed within trench174using various suitable deposition processes.

At a step18, additional metal filling material is formed over the seed layer of metal filling (FIG.11I). That is, the material used to form metal filling124(e.g. copper) is deposited within trench174and over the seed layer of metal filling. The additional metal filling material can be over-filled as illustrated inFIG.11Isuch that it completely fills trench174and excess material resides above barrier metal layer134and insulating layer144. The over-filling of the additional metal filling material can prevent formation of air voids and other undesirable effects that can result from an incomplete filling of the metal material.

At a step19, excess metal filling material and excess barrier metal material are removed (FIG.11J). In some embodiments, the excess metal filling material and the excess barrier metal material are removed using a chemical-mechanical planarization process, however other suitable removal processes are also contemplated. As illustrated inFIG.11J, the removal of excess metal filling material and excess barrier metal material can result in a structure wherein the top surfaces of insulating layer144, barrier metal layer134, and metal filling124are flush or approximately flush with each other such that the top of hybrid via interconnect structure100is flat or approximately flat. After step19, the formation of hybrid via interconnect structure100is generally complete. Various different embodiments of hybrid via interconnect structure100are discussed in detail below with respect toFIGS.2-10.

As shown inFIG.2, another embodiment of hybrid via interconnect structure100includes a gap formed in barrier metal layer134such that hybrid via110is in contact with metal filling124. To form the structure shown inFIG.2, process10can be adapted such that a blocking layer is selectively deposited over hybrid via110between steps16and17(as indicated by step16-1inFIG.11A) and removed after step17(as indicated by step17-1inFIG.11A). More detail regarding such a blocking layer is described below. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.2can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.3, another embodiment of hybrid via interconnect structure100includes a gap formed in capping layer160such that hybrid via110is in contact with metal filling122. To form the structure shown inFIG.3, process10can be adapted such that the formation of trench172performed in step13results in an extension of trench172into and through capping layer160. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.3can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.4, another embodiment of hybrid via interconnect structure100includes both a gap formed in barrier metal layer134such that hybrid via110is in contact with metal filling124and a gap formed in capping layer160such that hybrid via110is in contact with metal filling122. To form the gap in barrier metal layer134, process10can be adapted such that a blocking layer is selectively deposited over hybrid via110between steps16and17, and removed during step17after barrier metal layer134is formed. To form the gap in capping layer160, process10can be adapted such that the formation of trench172performed in step13results in an extension of trench172into and through capping layer160. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.4can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.5, another embodiment of hybrid via interconnect structure100does not include capping layer160. In this structure, etch stop layer150and hybrid via110are in contact with metal filling122and provide a barrier on a top surface of metal filling122instead of capping layer160. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.5can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.6, another embodiment of hybrid via interconnect structure100does not include capping layer160but does include a gap formed in barrier metal layer134such that hybrid via110is in contact with metal filling124. To form the gap in barrier metal layer134, process10can be adapted such that a blocking layer is selectively deposited over hybrid via110between steps16and17, and removed during step17after barrier metal layer134is formed. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.6can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.7, another embodiment of hybrid via interconnect structure100includes a gap formed in capping layer160and an extension of hybrid via110into metal filling122. Process10can be adapted such that the formation of trench172in step13results in an extension of trench172into and through capping layer160and into metal filling122such that a recess is formed within metal filling122. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.7can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.8, another embodiment of hybrid via interconnect structure100includes a gap formed in barrier metal layer134such that hybrid via110is in contact with metal filling124, a gap formed in capping layer160, and an extension of hybrid via110into metal filling122. To form the gap in barrier metal layer134, process10can be adapted such that a blocking layer is selectively deposited over hybrid via110between steps16and17, and removed during step17after barrier metal layer134is formed. Further, process10can be adapted such that the formation of trench172performed in step13results in an extension of trench172into and through capping layer160and into metal filling122such that a recess is formed within metal filling122. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.8can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.9, another embodiment of hybrid via interconnect structure100does not include capping layer160, but does include an extension of hybrid via110into metal filling122. Process10can be adapted such that the formation of trench172performed in step13results in an extension of trench172into metal filling122such that a recess is formed within metal filling122. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.9can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.10, another embodiment of hybrid via interconnect structure100does not include capping layer160, but does include both a gap formed in barrier metal layer134such that hybrid via110is in contact with metal filling124and an extension of hybrid via110into metal filling122. To form the gap in barrier metal layer134, process10can be adapted such that a blocking layer is selectively deposited over hybrid via110between steps16and17, and removed during step17after barrier metal layer134is formed. Further, process10can be adapted such that the lithography and etching performed in step13results in an extension of trench172into metal filling122such that a recess is formed within metal filling122. Depending on the application, the embodiment of hybrid via interconnect structure100illustrated inFIG.10can provide improved ease of fabrication and reduced contact resistance. Structures similar to hybrid via interconnect structure100can also be formed using a dual damascene process as discussed in more detail below with respect toFIGS.12-48F.

FIGS.12-47illustrate cross sections of various embodiments of a hybrid via interconnect structure200that is formed using a dual damascene process. Hybrid via interconnect structure200can generally be formed during the BEOL portion of an IC fabrication process. As shown inFIG.12, hybrid via interconnect structure200includes a first metal filling222and a second metal filling224electrically connected by a hybrid via210. Metal filling222is surrounded by a barrier metal layer232and a capping layer260. Metal filling224is surrounded by a barrier metal layer234. Metal filling222can be completely surrounded by the combination of barrier metal layer232and capping layer260. Metal filling224can be partially surrounded by barrier metal layer234or completely surrounded by barrier metal layer234(although this is not explicitly shown inFIG.12). These layers are adjacent to an insulating layer242and an insulating layer244separated by an etch stop layer250.

In some embodiments, both metal filling222and metal filling224are copper interconnects. However, metal filling222and metal filling224can be formed of other suitable materials (e.g. aluminum, etc.). Barrier metal layer232and barrier metal layer234chemically isolate metal filling222and metal filling224, respectively, from surrounding materials such as silicon and other materials. For example, barrier metal layer232can prevent diffusion of metal filling222into insulating layer242. Barrier metal layer232and barrier metal layer234can be formed using materials such as tantalum, cobalt, ruthenium, and other suitable materials. Barrier metal layer232and barrier metal layer234are generally formed of material(s) that are effective in chemically isolating metal filling222and metal filling224while also being effective electrical conductors.

Insulating layer242and insulating layer244are generally dielectric materials with low electrical conductivity. For example, insulating layer242and insulating layer244can be formed of materials including silicon nitride, silicon oxide, and other suitable materials with a relatively high dielectric constants (high-k materials). Etch stop layer250can generally prevent over-etching such that structures below etch stop layer250(e.g. insulating layer242, capping layer260, etc.) are not damaged when structures above etch stop layer250are being etched. Further, etch stop layer250can facilitate improved precision during various etching processes. For example, a first etching process can be used until etch stop layer250is reached, and then a second etching process can be used to remove a portion of etch stop layer250that is exposed as a result of the first etching process. Etch stop layer250can be formed of materials such as silicon nitride, silicon carbide, silicon carbonitride, and other suitable materials. Capping layer260can generally be included to reduce electromigration within hybrid via interconnect structure200. Capping layer260can be formed using various materials such as silicon carbon nitride, silicon nitride, cobalt tungsten phosphide, copper alloys, and other suitable materials and combinations thereof.

Hybrid via210itself can be formed of various materials including metals (e.g. aluminum, copper, cobalt, nickel, tungsten, ruthenium, molybdenum, platinum, palladium, etc.), alloys (copper/zinc alloys, iron/cobalt alloys, molybdenum/tantalum alloys, etc.), other conductive materials (e.g. fullerenes, carbon nanotubes, molybdenum disulfide, etc.), and other suitable materials and combinations thereof. Hybrid via210is generally formed of different material(s) than metal filling222, metal filling224, barrier metal layer232, and barrier metal layer234. The use of different material(s) for hybrid via210can enable metallization for advanced nodes and can reduce contact resistance associated with hybrid via interconnect structure200overall.

Hybrid via interconnect structure200can generally provide reduced contact resistance and reduced interconnect resistance due to a variety of factors. For example, especially in wrapped via structures such as shown inFIGS.18-21,23,25,27-31,36-39,41, and43-47(where metal filling222and/or metal filling224is in contact with and wrapped around part of hybrid via110), contact resistance can be reduced due to a larger contact area between hybrid via210and metal filling222and/or metal filling224. Further, with the development of more advanced semiconductor nodes, various embodiments of hybrid via interconnect structure200can be easier and/or more efficient to produce.

FIG.48Ais a flow diagram illustrating a process20for forming hybrid via interconnect structure200.FIGS.48B-48Fillustrate various steps of process20. Hybrid via interconnect structure200formed using process20can have lower contact and interconnect resistance and thereby improved performance when compared to some previous approaches. Further, process20can provide advantages in terms of ease and efficiency in the interconnect structure fabrication process in different applications when compared to some previous approaches. Process20is generally a dual damascene process that involves formation of hybrid via210that electrically connects a metal filling222and a metal filling224. Hybrid via210is generally formed of different material(s) than metal filling222and metal filling224. Various adaptions of process20are contemplated such as described with respect toFIGS.13-47.

At a step21, a first trench and a second trench are formed within an insulating layer that is formed over a first interconnect structure (FIG.48B). As illustrated inFIG.48B, a trench272and a trench274are formed within insulating layer244. As process20is a dual damascene process, both trench272and trench274can be formed before hybrid via210is formed, as opposed to process10wherein first trench172is formed, then hybrid via110is formed, then trench174is formed. The first interconnect structure includes metal filling222, barrier metal layer232, insulating layer242, etch stop layer250, and capping layer260. The first interconnect structure can be formed on top of a contact, such as a contact formed during the MEOL portion of an IC fabrication process. For example, the first interconnect structure can be formed over a gate contact. The first interconnect structure can be formed by depositing insulating layer242on a contact surface, forming a trench within insulating layer242, forming barrier metal layer232within the trench, forming a seed layer of metal filling over barrier metal layer232, forming additional metal filling material over the seed layer to form metal filling222, removing excess material from metal filling222and barrier metal layer232, forming capping layer260over metal filling222and barrier metal layer232, and forming etch stop layer250over insulating layer242and capping layer260.

At a step22, a hybrid via is formed within the first trench (FIG.48C). As illustrated inFIG.48C, hybrid via210is formed within trench272by filling materials such as metals, alloys, and/or other conductive materials within trench272. As illustrated inFIG.48C, hybrid via210is formed such that a top surface of hybrid via210is flush or approximately flush with a bottom surface of trench274. However, as discussed below with respect toFIGS.13-47, hybrid via210can also be formed such that it extends into trench274. Hybrid via210can be formed using processes such as physical vapor deposition, chemical vapor deposition, atomic layer deposition, electrochemical deposition, and other suitable processes and combinations thereof. In some embodiments, the process temperature for forming of hybrid via210ranges from about 20 degrees Celsius to 1000 degrees Celsius, however process temperatures outside of this range are also contemplated. Further, in some embodiments, hybrid via210ranges from about 5 angstroms to 100 microns in height, however heights outside of this range are also contemplated.

At a step23, a barrier metal layer and a seed layer of metal filling are formed within the second trench (FIG.48D). First, barrier metal layer234is deposited within trench274. Barrier metal layer234can be formed of materials such as tantalum, cobalt, ruthenium, and other similar materials that are effective in chemically isolating metal filling224while also being effective electrical conductors. Then, the seed layer of metal filling (e.g. copper material) is formed over barrier metal layer234. The seed layer of metal filling can provide improvements in the formation of metal filling224itself. For example, the seed layer can prevent formation of small air voids that can be formed between barrier metal layer234and metal filling224without the use of the seed layer. Barrier metal layer234and the seed layer of metal filling can be formed within trench274using various suitable deposition processes.

At a step24, additional metal filling material is formed over the seed layer of metal filling (FIG.48E). That is, the material used to form metal filling224(e.g. copper) is deposited within trench274and over the seed layer of metal filling. The additional metal filling material can be over-filled as illustrated inFIG.48Esuch that it completely fills trench274and excess material resides above barrier metal layer234and insulating layer244. The over-filling of the additional metal filling material can prevent formation of air voids and other undesirable effects that can result from an incomplete filling.

At a step25, excess metal filling material and excess barrier metal material is removed (FIG.48F). In some embodiments, the excess metal filling material and excess barrier metal material are removed using a chemical-mechanical planarization process. As illustrated inFIG.48F, the removal of excess metal filling material and excess barrier metal material can result in a structure wherein the top surfaces of insulating layer244, barrier metal layer234, and metal filling224are flush or approximately flush with each other such that the top of hybrid via interconnect structure200is flat or approximately flat. After step25, the formation of hybrid via interconnect structure200is generally complete. Various different embodiments of hybrid via interconnect structure100are discussed in detail below with respect toFIGS.13-47.

As shown inFIG.13, another embodiment of hybrid via interconnect structure200includes a gap formed in barrier metal layer234such that hybrid via210is in contact with metal filling224. To form the structure shown inFIG.13, process20can be adapted such that a blocking layer is selectively deposited over hybrid via210between steps22and23(as indicated by step22-1inFIG.48A) and removed after barrier metal layer234is formed in step23has indicated by step23-1inFIG.48A). The blocking layer is described in more detail below. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.13can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.14, another embodiment of hybrid via interconnect structure200includes a gap formed in capping layer260such that hybrid via210is in contact with metal filling222. To form the structure shown inFIG.14, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.14can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.15, another embodiment of hybrid via interconnect structure200includes both includes a gap formed in barrier metal layer234such that hybrid via210is in contact with metal filling224and a gap formed in capping layer260such that hybrid via210is in contact with metal filling222. To form the gap in barrier metal layer234, process20can be adapted such that a blocking layer is selectively deposited over hybrid via210between steps22and23, and removed during step23after barrier metal layer234. To form the gap in capping layer260, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.15can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.16, another embodiment of hybrid via interconnect structure200does not include capping layer260. In this structure, etch stop layer250and hybrid via210are both in contact with metal filling222instead of capping layer260. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.16can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.17, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include a gap formed in in barrier metal layer234such that hybrid via210is in contact with metal filling224. In this structure, hybrid via210is in contact with both metal filling222and metal filling224. To form the gap in barrier metal layer234, process20can be adapted such that a blocking layer is selectively deposited over hybrid via210between steps22and23, and removed after forming barrier metal layer234in step23. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.17can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.18, another embodiment of hybrid via interconnect structure200includes a gap formed in capping layer260and an extension of hybrid via210into metal filling222. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222. Then, hybrid via210can be formed within the recess at step22such that metal filling222is in contact with and wrapped around a portion of hybrid via210. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.18can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.19, another embodiment of hybrid via interconnect structure200includes a gap formed in in barrier metal layer234such that hybrid via210is in contact with metal filling224, a gap formed in capping layer260, and an extension of hybrid via210into metal filling222. To form the gap in barrier metal layer234, process20can be adapted such that a blocking layer is selectively deposited over hybrid via210between steps22and23, and removed during step23after barrier metal layer234is formed. Further, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222. Then, hybrid via210can be formed within the recess at step22such that metal filling222is in contact with and wrapped around a portion of hybrid via210. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.19can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.20, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include an extension of hybrid via210into metal filling222. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222. Then, hybrid via210can be formed within the recess at step22such that metal filling222is in contact with and wrapped around a portion of hybrid via210. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.20can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.21, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include includes a gap formed in in barrier metal layer234such that hybrid via210is in contact with metal filling224and an extension of hybrid via210into metal filling222. To form the gap in barrier metal layer234, process20can be adapted such that a blocking layer is selectively deposited over hybrid via210between steps22and23, and removed during step23after barrier metal layer234is formed. Further, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222. Then, hybrid via210can be formed within the recess at step22such that metal filling222is in contact with and wrapped around a portion of hybrid via210. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.21can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.22, another embodiment of hybrid via interconnect structure200includes an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is surrounded by barrier metal layer234such that hybrid via210is not in contact with metal filling224. To form the structure shown inFIG.22, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.22can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.23, another embodiment of hybrid via interconnect structure200includes an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is not surrounded by barrier metal layer234and is instead barrier-free in that metal filling224is in contact with and wrapped around a portion of hybrid via210. In this sense, a recess is formed within metal filling224that is filled by hybrid via210. To form this structure, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Further, a blocking layer can be selectively deposited over hybrid via210between steps22and23, and removed during step23after barrier metal layer234is formed. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.23can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.24, another embodiment of hybrid via interconnect structure200includes a gap formed in capping layer260such that hybrid via210is in contact with metal filling222and an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is surrounded by barrier metal layer234such that hybrid via210is not in contact with metal filling224. To form the gap in capping layer260, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260. Further, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.22can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.25, another embodiment of hybrid via interconnect structure200includes a gap formed in capping layer260and an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is not surrounded by barrier metal layer234and is instead barrier-free in that metal filling224is in contact with and wrapped around a portion of hybrid via210. To form the gap in capping layer260, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260. Further, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274, and a blocking layer can be selectively deposited over hybrid via210between steps22and23and removed during step23after barrier metal layer234is formed. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.25can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.26, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is surrounded by barrier metal layer234such that hybrid via210is not in contact with metal filling224. Without capping layer260, both hybrid via210and etch stop layer250are in contact with metal filling222. Process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.26can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.27, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is not surrounded by barrier metal layer234and is instead barrier-free in that metal filling224is in contact with and wrapped around a portion of hybrid via210. Process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Further, a blocking layer can be selectively deposited over hybrid via210between steps22and23. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.27can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.28, another embodiment of hybrid via interconnect structure200includes a gap formed in capping layer260, an extension of hybrid via210into metal filling222, and an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is surrounded by barrier metal layer234such that hybrid via210is not in contact with metal filling224. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222. Further, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.28can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.29, another embodiment of hybrid via interconnect structure200includes a gap formed in capping layer260, an extension of hybrid via210into metal filling222, and an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is not surrounded by barrier metal layer234and is instead barrier-free in that metal filling224is in contact with and wrapped around a portion of hybrid via210. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222. Further, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274, and a blocking layer can be selectively deposited over hybrid via210between steps22and23and removed after barrier metal layer234is formed in step23. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.29can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.30, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of hybrid via210into metal filling222and an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is surrounded by barrier metal layer234such that hybrid via210is not in contact with metal filling224. Process20can be adapted such that the formation trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222. Further, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.30can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.31, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of hybrid via210into metal filling222and an extension of hybrid via210into metal filling224, wherein the portion of hybrid via210that extends into metal filling224is not surrounded by barrier metal layer234and is instead barrier-free in that metal filling224is in contact with and wrapped around a portion of hybrid via210. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222. Further, process20can be adapted at step22such that hybrid via210not only fills trench272, but it also extends into trench274, and a blocking layer can be selectively deposited over hybrid via210between steps22and23and removed during step23after barrier metal layer234if formed. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.31can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.32, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with metal filling222, etch stop layer250, or insulating layer244but is in contact with metal filling224. To form this structure, process20can be adapted such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.32can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.33, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244, but is in contact with both metal filling222and metal filling224. To form this structure, process20can be adapted such that a blocking layer is selectively deposited within trench272and over metal filling222after step21, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.33can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.34, another embodiment of hybrid via interconnect structure200includes capping layer260and includes an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with capping layer260, etch stop layer250, or insulating layer244but is in contact with metal filling224. To form this structure, process20can be adapted such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.34can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.35, another embodiment of hybrid via interconnect structure200includes capping layer260and includes an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250, but is in contact with both metal filling224and capping layer260. Process20can be adapted such that a blocking layer is selectively deposited within trench272and over capping layer260after step21, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.35can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.36, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with metal filling222, etch stop layer250, or insulating layer244as well as an extension of hybrid via210into metal filling224. Process20can be adapted such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.36can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.37, another embodiment of hybrid via interconnect structure200does not include capping layer260but does include an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250, as well as an extension of hybrid via210into metal filling224. Process20can be adapted such that a blocking layer is selectively deposited within trench272and over metal filling222after step21, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.37can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.38, another embodiment of hybrid via interconnect structure200includes capping layer260, an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with capping layer260, etch stop layer250, or insulating layer244, and an extension of hybrid via210into metal filling224. Process20can be adapted such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.38can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.39, another embodiment of hybrid via interconnect structure200includes capping layer260, an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250, and an extension of hybrid via210into metal filling224. Process20can be adapted such that a blocking layer is selectively deposited within trench272and over capping layer260after step21, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.39can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.40, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of hybrid via210into metal filling222and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244, etch stop layer250, or metal filling222. To form this structure, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.40can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.41, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of hybrid via210into metal filling222and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222, a blocking layer is selectively deposited within the recess formed within metal filling222after step21, and step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.41can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.42, another embodiment of hybrid via interconnect structure200includes capping layer260, an extension of hybrid via210into metal filling222, and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244, capping layer260, etch stop layer250, or metal filling222. To form this structure, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.42can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.43, another embodiment of hybrid via interconnect structure200includes capping layer260, an extension of hybrid via210into metal filling222, and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250. To form this structure, process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222, a blocking layer is selectively deposited within the recess formed within metal filling222after step21, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.43can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.44, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of hybrid via210into metal filling222, an extension of hybrid via210into metal filling224, and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with metal filling222, insulating layer244, or etch stop layer250. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.44can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.45, another embodiment of hybrid via interconnect structure200does not include capping layer260, but does include an extension of hybrid via210into metal filling222, an extension of hybrid via210into metal filling224, and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into metal filling222such that a recess is formed within metal filling222, a blocking layer is selectively deposited within the recess formed within metal filling222after step21, and step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.45can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.46, another embodiment of hybrid via interconnect structure200includes capping layer260, an extension of hybrid via210into metal filling222, an extension of hybrid via210into metal filling224, and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with metal filling222, insulating layer244, etch stop layer250, or capping layer260. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222, and such that step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.46can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.47, another embodiment of hybrid via interconnect structure200includes capping layer260, an extension of hybrid via210into metal filling222, an extension of hybrid via210into metal filling224, and an extension of barrier metal layer234around hybrid via210such that hybrid via210is not in contact with insulating layer244or etch stop layer250. Process20can be adapted such that the formation of trench272performed in step21results in an extension of trench272into and through capping layer260and into metal filling222such that a recess is formed within metal filling222, a blocking layer is selectively deposited within the recess formed within metal filling222after step21, and step23occurs before step22. That is, barrier metal layer234can be formed within trench272and within trench274before hybrid via210is formed. Additionally, hybrid via210can be formed such that it not only fills trench272, but it also extends into trench274, and the seed layer of metal filling can be formed over the portions of hybrid via210and barrier metal layer234that remain exposed within trench274after the formation of hybrid via210and before the formation of the additional metal filling material in step24. Depending on the application, the embodiment of hybrid via interconnect structure200illustrated inFIG.47can provide improved ease of fabrication and reduced contact resistance. Structures similar to hybrid via interconnect structure100and hybrid via interconnect structure200can also be formed using a reactive ion etching process as discussed in more detail below with respect toFIGS.12-48F.

FIGS.49-64illustrate cross sections of various embodiments of a hybrid via interconnect structure300that is formed using a reactive ion etching process. Hybrid via interconnect structure300can generally be formed during the BEOL portion of an IC fabrication process. As shown inFIG.49, hybrid via interconnect structure300includes a metal filling322and a metal layer380electrically connected by a hybrid via310. Metal filling322is surrounded by a barrier metal layer332. Metal layer380is surrounded by a barrier metal layer334. Metal filling322can be completely surrounded by the combination of barrier metal layer332, an etch stop layer352, and hybrid via310. Metal layer380can be partially surrounded by barrier metal layer234or completely surrounded by barrier metal layer234(although this is not explicitly shown inFIG.49). These layers are adjacent to an insulating layer342, an insulating layer344, and an insulating layer346separated by an etch stop layer352and an etch stop layer354.

In some embodiments, metal filling322is a copper interconnect. However, metal filling322can be formed of other suitable materials (e.g. aluminum, etc.). Metal layer380is generally formed of a metal material suitable for use in a reactive ion etching (ME) process. That is, metal layer380can generally be formed of an RIE metal such as aluminum, chromium, titanium, and other suitable metals and combinations thereof. In order to pattern metal layer380, a layer of photoresist can be applied over a portion of metal layer380, and the remaining exposed portions of metal layer380can be patterned using chemically reactive ions such as chlorine-based ions and other types of ions that are accelerated towards metal layer380. As an end result, the exposed portion of metal layer380that does not lie underneath the photoresist can be removed down to etch stop layer354. Barrier metal layer332and barrier metal layer334chemically isolate metal filling322and metal layer380, respectively, from surrounding materials such as silicon and other materials. For example, barrier metal layer332can prevent diffusion of metal filling322into insulating layer342. Barrier metal layer332and barrier metal layer334can be formed using materials such as tantalum, cobalt, ruthenium, and other suitable materials. Barrier metal layer332and barrier metal layer334are generally formed of a material that is effective in chemically isolating metal filling322and metal layer380while also being effective electrical conductors.

Insulating layer342, insulating layer344, and insulating layer346are generally dielectric materials with low electrical conductivity. For example, insulating layer342, insulating layer344, and insulating layer346can be formed of materials including silicon nitride, silicon oxide, and other materials with a relatively high dielectric constants (high-k materials). Etch stop layer352and etch stop layer354can generally prevent over-etching such that structures below etch stop layer352and etch stop layer354are not damaged. For example, a first etching process can be used until etch stop layer352is reached, and then a second etching process can be used to remove a portion of etch stop layer352that is exposed as a result of the first etching process. Etch stop layer352and etch stop layer354can be formed of materials such as silicon nitride, silicon carbide, silicon carbonitride, and other similar materials.

Hybrid via310itself can be formed of various materials including metals (e.g. aluminum, copper, cobalt, nickel, tungsten, ruthenium, molybdenum, platinum, palladium, etc.), alloys (copper/zinc alloys, iron/cobalt alloys, molybdenum/tantalum alloys, etc.), other conductive materials (e.g. fullerenes, carbon nanotubes, molybdenum disulfide, etc.), and various other suitable materials and combinations thereof. Hybrid via310is generally formed of different material(s) than metal filling322, metal layer380, barrier metal layer332, and barrier metal layer334are formed of. The use of different material(s) for hybrid via310can enable metallization for advanced nodes and can reduce contact resistance associated with hybrid via interconnect structure300overall.

Hybrid via interconnect structure300can generally provide reduced contact resistance and reduced interconnect resistance due to a variety of factors. For example, especially in wrapped via structures such as shown inFIGS.54and56-64(where metal filling322and/or metal layer380is in contact with and wrapped around part of hybrid via310), contact resistance can be reduced due to a larger contact area between hybrid via310and metal filling322and/or metal layer380. Further, with the development of more advanced semiconductor nodes, various embodiments of hybrid via interconnect structure300can be easier and/or more efficient to produce.

FIG.65Ais a flow diagram illustrating a process30for forming hybrid via interconnect structure300.FIGS.65B-65Iillustrate various steps of process30. Process30can generally be used to form hybrid via interconnect structure300which can have lower contact resistance and thereby improved performance when compared to some previous approaches. Further, process30can provide advantages in terms of ease of fabrication in different applications when compared to some previous approaches. Process30is generally a reactive ion etching process that involves formation of hybrid via310that electrically connects metal filling322and metal layer380. Hybrid via310is generally formed of a different material than metal filling322, metal layer380, and barrier metal layers332and334. Various adaptions of process30are contemplated such as described with respect toFIGS.50-64.

At a step31, a trench is formed within an insulating layer that is formed over a first interconnect structure (FIG.65B). As illustrated inFIG.65B, a trench370is formed within insulating layer344. The first interconnect structure includes metal filling322, barrier metal layer332, insulating layer342, and etch stop layer352. The first interconnect structure can be formed on top of a contact, such as a contact formed during the MEOL portion of an integrated circuit fabrication process. For example, the first interconnect structure can be formed over a gate contact. The first interconnect structure can be formed by depositing insulating layer342on a contact surface, using lithography and etching techniques to form a trench within insulating layer342, depositing barrier metal layer332within the trench, forming a seed layer of metal filling material over barrier metal layer332, depositing additional metal filling material over the seed layer to form metal filling322, using chemical-mechanical planarization to remove excess material from metal filling322and barrier metal layer332, and depositing etch stop layer352over insulating layer342, barrier metal layer332, and metal filling322. Then, insulating layer344is formed over etch stop layer352, and trench370is formed within insulating layer344using lithography and etching techniques.

At a step32, a hybrid via is formed within the trench (FIG.65C). As illustrated inFIG.65C, hybrid via310is formed within trench370by filling materials such as metals, alloys, and/or other conductive materials within trench370. As illustrated inFIG.65C, hybrid via310is formed such that a top surface of hybrid via310is flush or approximately flush with a top surface of insulating layer344. However, as discussed below with respect toFIGS.50-64, hybrid via310can also be formed such that it extends above the top surface of insulating layer344. Hybrid via310can be formed using processes such as physical vapor deposition, chemical vapor deposition, atomic layer deposition, electrochemical deposition, and other suitable processes. In some embodiments, the process temperature for the formation of hybrid via310ranges from about 20 degrees Celsius to 1000 degrees Celsius, however process temperatures outside of this range are also contemplated. Further, in some embodiments, hybrid via310ranges in height from about 5 angstroms to 100 microns, however heights outside of this range are also contemplated.

At a step33, an etch stop layer is formed over the insulating layer and over the hybrid via (FIG.65D). As illustrated inFIG.65D, step33includes formation of etch stop layer354. Etch stop layer354is deposited over insulating layer344and hybrid via310, and can be formed of materials such as silicon nitride, silicon carbide, silicon carbonitride, and other suitable materials.

At a step34, a metal layer is formed over the etch stop layer (FIG.65E). The metal layer formed in step34is metal layer380. Metal layer380can be formed by depositing materials such as aluminum, chromium, titanium, and other suitable metals over etch stop layer354. Metal layer380is generally formed of material that is suitable for being patterned using a reactive ion etching process, as discussed below.

At a step35, a portion of the metal layer is removed using a reactive ion etching process (FIG.65F). As illustrated inFIG.65F, a portion of metal layer380is removed in step35. Step35can generally involve attacking metal layer380with chemically reactive ions that are generated under low pressure (e.g. a vacuum) by applying a strong electromagnetic field (e.g. a radio frequency (RF) field) to hybrid via interconnect structure300. A layer of photoresist material can be applied to certain areas of metal layer380to shield such areas from being attacked by the chemically reactive ions. However, the areas of metal layer380that do not lie underneath the photoresist material will be attacked by the chemically reactive ions and will be removed down to etch stop layer354as illustrated inFIG.65F.

At a step36, a barrier metal layer is formed over the metal layer (FIG.65G). The barrier metal layer formed in step36is barrier metal layer334. As illustrated inFIG.65G, barrier metal layer334can be deposited over the entire exposed surface of metal layer380and over etch stop layer354. Barrier metal layer334provides chemical isolation of metal layer380from surround materials such as silicon in insulating materials. Various suitable processes can be used to form barrier metal layer334in step36.

At a step37, an insulating layer is formed over the barrier metal layer (FIG.65H). The insulating layer formed in step37is insulating layer346. As illustrated inFIG.65H, insulating layer346is deposited over barrier metal layer334. Formation of insulating layer346in step37can include depositing material(s) with a high dielectric constant (high-k) such as silicon oxide and silicon nitride, among other suitable materials. Various suitable processes can be used to form insulating layer346in step37.

At a step38, excess insulating material and excess barrier metal material are removed (FIG.65I). In some embodiments, the excess insulating material and excess barrier metal material are removed using a chemical-mechanical planarization process. As illustrated inFIG.65I, the removal of excess insulating material and excess barrier metal material can result in a structure wherein the top surfaces of insulating layer346, barrier metal layer334, and metal layer380are flush or approximately flush with each other such that the top of hybrid via interconnect structure300is flat or approximately flat. After step38, the formation of hybrid via interconnect structure300is generally complete. Various different embodiments of hybrid via interconnect structure300are discussed in detail below with respect toFIGS.50-64.

As shown inFIG.50, another embodiment of hybrid via interconnect structure300includes a gap formed in etch stop layer354such that hybrid via310is in contact with metal layer380. To from this structure, process30can be adapted such that a layer of blocking material is selectively deposited over hybrid via310between steps32and33(as indicated by step32-1inFIG.65A), and removed after step33(as indicated by step33-1inFIG.65A). Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.50can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.51, another embodiment of hybrid via interconnect structure300includes a capping layer360. To form this structure, capping layer360can be formed during the formation of the first interconnect structure before step31of process30. Capping layer360can generally be included to reduce electromigration within hybrid via interconnect structure300. Capping layer360can be formed using various materials such as silicon carbon nitride, silicon nitride, cobalt tungsten phosphide, copper alloys, and other suitable materials and combinations thereof. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.51can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.52, another embodiment of hybrid via interconnect structure300includes capping layer360and a gap formed in etch stop layer354such that hybrid via310is in contact with metal layer380. Process30can be adapted such that a layer of blocking material is selectively deposited over hybrid via310between steps32and33, and removed after33. Further, capping layer360can be included during the formation of the first interconnect structure before step31of process30. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.52can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.53, another embodiment of hybrid via interconnect structure300includes an extension of hybrid via310into metal layer380and an extension of etch stop layer354such that hybrid via310is not in contact with metal layer380. To form this structure, process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, etch stop layer354can be formed over hybrid via310and insulating layer344in step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.53can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.54, another embodiment of hybrid via interconnect structure300includes an extension of hybrid via310into metal layer380and a gap formed in etch stop layer354such that hybrid via310is in contact with metal layer380. In this sense, a recess is formed within metal layer380that is filled by hybrid via310. To form this structure, process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, a blocking layer can be selectively deposited over hybrid via310between steps32and33and removed after step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.54can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.55, another embodiment of hybrid via interconnect structure300includes capping layer360, an extension of hybrid via310into metal layer380, and an extension of etch stop layer354such that hybrid via310is not in contact with metal layer380. Process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, etch stop layer354can be formed over hybrid via310and insulating layer344in step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.55can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.56, another embodiment of hybrid via interconnect structure300includes capping layer360, an extension of hybrid via310into metal layer380, and a gap formed in etch stop layer354such that hybrid via310is in contact with metal layer380. Process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, a blocking layer can be selectively deposited over hybrid via310between steps32and33and removed after step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.56can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.57, another embodiment of hybrid via interconnect structure300includes an extension of hybrid via310into metal filling322. To form this structure, process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.57can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.58, another embodiment of hybrid via interconnect structure300includes a gap formed in etch stop layer354such that hybrid via310is in contact with metal layer380and an extension of hybrid via310into metal filling322. Process30can be adapted such that a layer of blocking material is selectively deposited over hybrid via310between steps32and33and removed after step33. Further, process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.58can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.59, another embodiment of hybrid via interconnect structure300includes capping layer360and an extension of hybrid via310into metal filling322. Process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into and through capping layer360and into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.59can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.60, another embodiment of hybrid via interconnect structure300includes capping layer360, a gap formed in etch stop layer354such that hybrid via310is in contact with metal layer380, and an extension of hybrid via310into metal filling322. Process30can be adapted such that a layer of blocking material is selectively deposited over hybrid via310between steps32and33and removed after step33. Further, process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into and through capping layer360and into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.60can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.61, another embodiment of hybrid via interconnect structure300includes an extension of hybrid via310into metal filling322, an extension of hybrid via310into metal layer380, and an extension of etch stop layer354such that hybrid via310is not in contact with metal layer380. Process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Further, process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, etch stop layer354can be formed over hybrid via310and over insulating layer344in step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.61can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.62, another embodiment of hybrid via interconnect structure300includes an extension of hybrid via310into metal filling322such that hybrid via310is in contact with metal filling322, an extension of hybrid via310into metal layer380such that hybrid via310is in contact with metal layer380, and a gap formed in etch stop layer354. Process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Further, process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, a blocking layer can be selectively deposited over hybrid via310between steps32and33, and removed after step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.62can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.63, another embodiment of hybrid via interconnect structure300includes capping layer360, an extension of hybrid via310into metal filling322, an extension of hybrid via310into metal layer380, and an extension of etch stop layer354such that hybrid via310is not in contact with metal layer380. Process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into and through capping layer360and into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Further, process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, etch stop layer354can be formed over hybrid via310and over insulating layer344in step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.63can provide improved ease of fabrication and reduced contact resistance.

As shown inFIG.64, another embodiment of hybrid via interconnect structure300includes capping layer360, an extension of hybrid via310into metal filling322such that hybrid via310is in contact with metal filling322, an extension of hybrid via310into metal layer380such that hybrid via310is in contact with metal layer380, and a gap formed in etch stop layer354. Process30can be adapted such that the formation of trench370performed in step31results in an extension of trench370into and through capping layer360and into metal filling322such that a recess is formed within metal filling322. Then, the material used to form hybrid via310can be filled within trench370and thereby within the recess formed within metal filling322. Further, process30can be adapted such that hybrid via310extends above insulating layer344when it is formed in step32. That is, the material used to form hybrid via310can be overfilled beyond the confines of trench370. Then, a blocking layer can be selectively deposited over hybrid via310between steps32and33, and removed after step33. Depending on the application, the embodiment of hybrid via interconnect structure300illustrated inFIG.64can provide improved ease of fabrication and reduced contact resistance.

The blocking layers described herein can be selectively deposited using a chemical vapor deposition process, an atomic layer deposition process, a spin coating process, a dipping process, a blade-coating process, an immersion process, and other suitable processes and combinations thereof. Further, the blocking layers described herein can be formed of materials including small molecules, polymers, organometallic compounds, and other suitable materials. Solutions for wet-coating the blocking layers described herein can include both protic and aprotic solvents. In some embodiments, the thickness of the blocking layers described herein range in thickness from about 2 angstroms to 100 microns, however thicknesses outside of this range are also contemplated. The blocking layers described herein can be removed using removal processes such as thermal removal, photolithography, chemical treatment, and other suitable processes and combinations thereof.

As described in detail above, various embodiments of the hybrid via interconnect structure disclosed herein can be used to provide improved interconnect structures within an integrated circuit. The hybrid via interconnect structure includes a hybrid via that generally provides an electrical connection between two metals such as two copper interconnects. The hybrid via can be formed of a variety of materials including metals, alloys, and other conductive materials. The hybrid via interconnect structure can be formed using a single damascene process, a dual damascene process, or a reactive ion etching process, for example. The hybrid via interconnect structure can provide advantages in terms of reduced contact and interconnect resistance as well as improved ease and efficiency of fabrication.

An implementation of the present disclosure is a circuit. The circuit includes a first metal filling at least partially surrounded by a first barrier metal layer, a second metal filling at least partially surrounded by a second barrier metal layer, and a hybrid via formed between the first metal filling and the second metal filling. The hybrid via provides an electrical connection between the first metal filling and the second metal filling.

Another implementation of the present disclosure is a method of fabrication a circuit. The method includes forming an insulating layer over a first interconnect structure, forming a trench within the insulating layer, forming a hybrid via within the trench, and forming a second interconnect structure over the hybrid via such that the hybrid via provides an electrical connection between the first interconnect structure and the second interconnect structure.

Yet another implementation of the present disclosure is a circuit. The circuit includes a metal filling at least partially surrounded by a first barrier metal layer, a metal layer at least partially surrounded by a second barrier metal layer, and a hybrid via formed between the metal filling and the metal layer. The hybrid via provides an electrical connection between the metal filling and the metal layer.