Patent Publication Number: US-2023145089-A1

Title: Vertical edge blocking (veb) technique for increasing patterning process margin

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. patent application Ser. No. 16/435,259, filed on Jun. 7, 2019, the entire contents of which is hereby incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     Embodiments of the disclosure are in the field of semiconductor structures and processing and, in particular, to methods for improving edge placement error margins by using vertical edge blocking (VEB) features. 
     BACKGROUND 
     In back end of line (BEOL) fabrication, conductive vias and insulative plugs are needed in order to provide the desired electrical routing between layers of the BEOL stack. During the fabrication of the vias and plugs, edge placement errors may generate defects in the device. For example, edge placement errors may result in the creation of unwanted vias that result in undesirable shorts in the BEOL stack. In some BEOL stacks, gratings are used to provide increased overlay margins to avoid edge placement errors. However, as critical dimensions continue to scale, the widths of the gratings decrease. Accordingly, the margins for edge placement error continue to decrease. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a cross-sectional illustration of a semiconductor device illustrating the edge placement error margin for patterning vias in an interconnect layer. 
         FIG.  1 B  is a cross-sectional illustration of a semiconductor device with a grating that includes a vertical edge blocking (VEB) mask layer that increases the edge placement error margin, in accordance with an embodiment. 
         FIG.  2 A  is a perspective view illustration of a semiconductor device that includes a cross-grating, in accordance with an embodiment. 
         FIG.  2 B  is a plan view illustration of the semiconductor device in  FIG.  2 A , in accordance with an embodiment. 
         FIG.  3 A  is a perspective view illustration of a semiconductor device after a VEB mask layer is conformally disposed over the cross-grating, in accordance with an embodiment. 
         FIG.  3 B  is a cross-sectional illustration of the semiconductor device in  FIG.  3 A , in accordance with an embodiment. 
         FIG.  4    is a cross-sectional illustration of a semiconductor device after a hardmask is disposed over the VEB mask layer, in accordance with an embodiment. 
         FIG.  5    is a cross-sectional illustration after a resist layer is disposed over the hardmask layer and patterned, in accordance with an embodiment. 
         FIG.  6 A  is a plan view illustration of a semiconductor device after the hardmask is patterned, in accordance with an embodiment. 
         FIG.  6 B  is a cross-sectional illustration of the semiconductor device in  FIG.  6 A , in accordance with an embodiment. 
         FIG.  7 A  is a plan view illustration of a semiconductor device after the patterned hardmask is recessed, in accordance with an embodiment. 
         FIG.  7 B  is a cross-sectional illustration of the semiconductor device in  FIG.  7 A , in accordance with an embodiment. 
         FIG.  8 A  is a cross-sectional illustration of a semiconductor device after the VEB mask layer is selectively removed in desired openings defined by the cross-grating, in accordance with an embodiment. 
         FIG.  8 B  is a cross-sectional illustration of the semiconductor device in  FIG.  8 A , in accordance with an embodiment. 
         FIG.  8 C  is a micrograph of a semiconductor device at a point of the processing similar to the illustration in  FIG.  7 A , in accordance with an embodiment. 
         FIG.  8 D  is a micrograph of a semiconductor device at a point of the processing similar to the illustration in  FIG.  8 A , in accordance with an embodiment. 
         FIG.  9 A  is a plan view illustration of a semiconductor device after the openings in the cross-grating are transferred into the underlying substrate, in accordance with an embodiment. 
         FIG.  9 B  is a cross-sectional illustration of the semiconductor device in  FIG.  9 A , in accordance with an embodiment. 
         FIG.  10 A  is a perspective view illustration of a semiconductor device after the VEB mask layer, the hardmask, and lines of the cross-grating are removed, in accordance with an embodiment. 
         FIG.  10 B  is a cross-sectional illustration of the semiconductor device in  FIG.  10 A , in accordance with an embodiment. 
         FIG.  10 C  is a plan view micrograph of a semiconductor device at a point of the processing similar to the illustration in  FIG.  10 A , in accordance with an embodiment. 
         FIG.  10 D  is a cross-sectional micrograph of a semiconductor device at a point of the processing similar to the illustration in  FIG.  10 B , in accordance with an embodiment. 
         FIG.  11    is a cross-sectional illustration of a semiconductor device after conductive material is disposed in the opening to form a via, in accordance with an embodiment. 
         FIG.  12 A  is a plan view illustration of a semiconductor device that comprises a grid of source/drain (S/D) contacts and gate contacts in a first interlayer dielectric (ILD), in accordance with an embodiment. 
         FIG.  12 B  is a cross-sectional illustration of the semiconductor device in  FIG.  12 A , in accordance with an embodiment. 
         FIG.  12 C  is a cross-sectional illustration of a semiconductor device after a VEB mask layer and a second ILD are disposed over the device, in accordance with an embodiment. 
         FIG.  12 D  is a cross-sectional illustration of a semiconductor device after the second ILD is patterned, in accordance with an embodiment. 
         FIG.  12 E  is a cross-sectional illustration of a semiconductor device after exposed portions of the VEB mask layer are removed, in accordance with an embodiment. 
         FIG.  12 F  is a cross-sectional illustration of a semiconductor device after a fill metal is disposed in the opening, in accordance with an embodiment. 
         FIG.  13    illustrates a computing device in accordance with one implementation of an embodiment of the disclosure. 
         FIG.  14    is an interposer implementing one or more embodiments of the disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Embodiments described herein comprise semiconductor devices and methods of forming such devices using vertical edge blocking (VEB) features. In the following description, numerous specific details are set forth, such as specific integration and material regimes, in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to one skilled in the art that embodiments of the present disclosure may be practiced without these specific details. In other instances, well-known features, such as integrated circuit design layouts, are not described in detail in order to not unnecessarily obscure embodiments of the present disclosure. Furthermore, it is to be appreciated that the various embodiments shown in the Figures are illustrative representations and are not necessarily drawn to scale. 
     Certain terminology may also be used in the following description for the purpose of reference only, and thus are not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, “below,” “bottom,” and “top” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, and “side” describe the orientation and/or location of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. 
     As noted above, edge placement error margins are continuing to decrease as semiconductor devices continue to scale to smaller critical dimensions. An example of the available edge placement error margin is shown in  FIG.  1 A . A semiconductor device  100  is shown in  FIG.  1 A . The semiconductor device  100  includes a substrate  105  and a grating  121  including a plurality of parallel lines. A hardmask  150  is disposed over the grating  121 , and a resist layer  160  and an antireflective coating  161  are disposed over the hardmask  150 . As shown, the grating  121  has a pitch P and each of the lines have a width W. For example, the pitch P may be approximately 30 nm and the width W may be approximately 12 nm. 
     As shown, an opening  163  over a channel between lines of the grating  121  is patterned into the resist layer  160 . The opening  163  may have an edge placement error margin M 1 . In cases where the pitch P is approximately 30 nm and the width W is approximately 12 nm, the edge placement error margin M 1  is only approximately 6 nm. That is, all overlay errors in the system can only add up to approximately 6 nm. If the overlay errors exceed 6 nm, there is a chance that the opening  163  will inadvertently extend over a neighboring channel. This will result in defects in the semiconductor device (e.g., undesirable vias or plugs). 
     Accordingly, embodiments disclosed herein include a vertical edge blocking (VEB) mask layer that increases the edge placement error margin. The increase in the margin allows for greater protection against printing defects and allows for improved scaling of the semiconductor device to smaller critical dimensions (CDs). An example of a semiconductor device  101  that utilizes a VEB mask layer  140  is shown in  FIG.  1 B . 
     Referring now to  FIG.  1 B , a cross-sectional illustration of a semiconductor device  101  is shown, in accordance with an embodiment. The semiconductor device  101  may be substantially similar to the semiconductor device  100  illustrated in  FIG.  1 A , with the exception that the grating  121  is lined with a VEB mask layer  140 . The VEB mask layer  140  is a conformal layer that is disposed along sidewall surfaces and top surfaces of the grating  121 . The inclusion of the VEB mask layer  140 , therefore, increases the width of the lines in the grating  121 . As such, the edge placement error margin M 2  is increased. For example, the edge placement error margin M 2  may be increased by an amount substantially equal to a thickness T of the VEB mask layer  140 . For example, the VEB mask layer  140  may have a thickness of approximately 5 nm. In such embodiments, the edge placement error margin M 2  may be increased from 6 nm to 11 nm. 
     In  FIG.  1 B , the grating  121  is only shown as a one-dimensional grating. However, it is to be appreciated that a two-dimensional grating (i.e., a cross-grating) may also benefit from the use of a VEB mask layer in order to improve overlay margins in both directions. Examples of processes which use a VEB mask layer with a cross-grating architecture are shown in  FIGS.  2 A- 11   . 
     Referring now to  FIGS.  2 A and  2 B , a perspective view illustration and a corresponding plan view illustration of a semiconductor device  200  are shown, respectively, in accordance with an embodiment. In the illustrated embodiment, only a portion of the back end of line (BEOL) stack is shown. It is to be appreciated that the BEOL stack may be disposed over a semiconductor substrate. In an embodiment, the underlying semiconductor substrate may be a general workpiece object used to manufacture integrated circuits. The semiconductor substrate often includes a wafer or other piece of silicon or another semiconductor material. Suitable semiconductor substrates include, but are not limited to, single crystal silicon, polycrystalline silicon and silicon on insulator (SOI), as well as similar substrates formed of other semiconductor materials, such as substrates including germanium, carbon, or group III-V materials. The semiconductor substrate, depending on the stage of manufacture, often includes transistors, integrated circuitry, and the like. The substrate may also include semiconductor materials, metals, dielectrics, dopants, and other materials commonly found in semiconductor substrates. 
     In the illustrated embodiment, an interconnect layer of the BEOL stack is shown. For example, a metal layer  203  and a stack of one or more substrate layers  205 ,  206  over the metal layer  203  are illustrated. The metal layer  203  may comprise conductive traces used to provide interconnects to devices on the underlying semiconductor substrate. In an embodiment, as is also used throughout the present description, metal layers or interconnect line material (and via material) is composed of one or more metal or other conductive structures. A common example is the use of copper lines and structures that may or may not include barrier layers between the copper and surrounding ILD material. As used herein, the term metal includes alloys, stacks, and other combinations of multiple metals. For example, the metal interconnect lines may include barrier layers (e.g., layers including one or more of Ta, TaN, Ti or TiN), stacks of different metals or alloys, etc. Thus, the interconnect lines may be a single material layer, or may be formed from several layers, including conductive liner layers and fill layers. Any suitable deposition process, such as electroplating, chemical vapor deposition or physical vapor deposition, may be used to form interconnect lines. In an embodiment, the interconnect lines are composed of a conductive material such as, but not limited to, Cu, Al, Ti, Zr, Hf, V, Ru, Co, Ni, Pd, Pt, W, Ag, Au or alloys thereof. The interconnect lines are also sometimes referred to in the art as traces, wires, lines, metal, or simply interconnect. 
     In an embodiment, the one or more substrate layers  205 ,  206  may include interlayer dielectric (ILD) material. As used throughout the present description, ILD material is composed of or includes a layer of a dielectric or insulating material. Examples of suitable dielectric materials include, but are not limited to, oxides of silicon (e.g., silicon dioxide (SiO 2 )), doped oxides of silicon, fluorinated oxides of silicon, carbon doped oxides of silicon, various low-k dielectric materials known in the arts, and combinations thereof. The interlayer dielectric material may be formed by techniques, such as, for example, chemical vapor deposition (CVD), physical vapor deposition (PVD), or by other deposition methods. 
     In an embodiment, a cross-grating may be formed over the substrate  206 . The cross-grating may comprise a plurality of parallel first lines  221  that extend in a first direction and a plurality of parallel second lines  222  that extend in a second direction. For example, the first direction is substantially orthogonal to the second direction. First lines  221  may be spaced at a first pitch and the second lines may be spaced at a second pitch. In some embodiments, the first pitch is substantially equal to the second pitch, though embodiments are not limited to such configurations. The first lines  221  and the second lines  222  of the cross-grating may be any suitable materials that are etch selective to the underlying substrate  206  and to each other. For example, the first lines  221  and the second lines  222  may comprise hardmask materials. In some embodiments, one or both of the first lines  221  and the second lines  222  may comprise a single material layer, or a stack of more than one material layers. 
     In an embodiment, the first lines  221  and the second lines  222  define a plurality of first openings  231  that expose portions of the underlying substrate  206 . In the embodiment illustrated in  FIG.  2 A  there is a topographical difference between the first lines  221  and the second lines  222  (e.g., the second lines  222  are wider and have a top surface that is above top surfaces of the first lines  221 ). However, it is to be appreciated that embodiments disclosed herein are not limited by topography, and any cross-grating architecture may be used in accordance with embodiments disclosed herein. 
     Referring now to  FIGS.  3 A and  3 B  a perspective view illustration and a corresponding cross-sectional illustration after a vertical edge blocking (VEB) mask layer  240  is disposed over the cross-grating are shown, respectively, in accordance with an embodiment. In an embodiment, the VEB mask layer  240  is a conformal layer. That is, the VEB mask layer  240  may line the sidewalls and top surface of the first lines  221  and the second lines  222  of the cross-grating. The VEB mask layer  240  may also be disposed over exposed top surfaces of the substrate  206  between the cross-grating. Any suitable conformal deposition process may be used to deposit the VEB mask layer  240 . For example, the VEB mask layer  240  may be deposited may include atomic layer deposition (ALD), CVD, or the like. In an embodiment, the VEB mask layer  240  may have a thickness T. In an embodiment, the thickness T may be approximately 10 nm or less, or approximately 5 nm or less. The VEB mask layer  240  may comprise a material that is etch selective to surrounding materials. For example, the VEB mask layer  240  may comprise silicon and nitrogen (e.g., SiN), silicon and oxygen (e.g., SiO 2 ), aluminum and oxygen (e.g., Al 2 O), or titanium and nitrogen (e.g., TiN). In an embodiment, the VEB mask layer  240  reduces the width of the openings defined by the cross-grating. For example, second openings  232  may be defined by the vertical portions of the VEB mask layer  240 . 
     Referring now to  FIG.  4   , a cross-sectional illustration after a hardmask  250  is disposed over the VEB mask layer  240  is shown, in accordance with an embodiment. In an embodiment, the hardmask  250  may fill the second openings  232 . The portion of the hardmask  250  that fills the second openings  232  may be referred to herein as hardmask  252 . In an embodiment, the hardmask  250  may be any suitable material that is etch selective to the VEB mask layer  240 . For example, the hardmask  252  may be a carbon hardmask, or the like. 
     Referring now to  FIG.  5   , a cross-sectional illustration after a patterning stack is disposed over the hardmask  250  and is patterned is shown, in accordance with an embodiment. In an embodiment, the patterning stack may comprise an antireflective coating (ARC)  262  and a resist layer  260 . It is to be appreciated that additional layers may also be included in the patterning stack. In an embodiment, an opening  263  may be patterned into the resist layer  260  (e.g., with a photolithography process). The opening  263  may be positioned above one of the second openings  232 . 
     Referring now to  FIGS.  6 A and  6 B , a plan view illustration and a corresponding cross-sectional illustration along line B-B′ after the hardmask  250  is patterned are shown, respectively, in accordance with an embodiment. In an embodiment, the opening  263  in the resist layer  260  is transferred into the hardmask  250  to form third openings  255  with an etching process. In an embodiment, the patterning process that forms the third opening  255  clears the exposed portions of the hardmask  250  including the portions of the hardmask  252  in the exposed second  232 . That is, the second opening  232  is substantially cleared during the patterning process, and sidewall surfaces of the VEB mask layer  240  are exposed. 
     Referring now to  FIGS.  7 A and  7 B , a plan view illustration and a corresponding cross-sectional illustration along line B-B′ after the hardmask  250  is recessed are shown, respectively, in accordance with an embodiment. In an embodiment, the hardmask  250  may be recessed so that only portions of the hardmask  252  in the second openings  232  remain. As shown, the top surfaces of the portions of the hardmask  252  are recessed below a top surface of the VEB mask layer  240 . In an embodiment, the hardmask  250 / 252  may be recessed with an etching process. 
     Referring now to  FIGS.  8 A and  8 B , a plan view illustration and a cross-sectional illustration along line B-B′ after the VEB mask layer  240  is selectively removed are shown, respectively, in accordance with an embodiment. In an embodiment, the VEB mask layer  240  may be etched with an isotropic etching process. The use of an isotropic etching process allows for the portion of the VEB mask layer  240  in the exposed second openings  232  to be cleared while preserving the portions of the VEB mask layer  240  that are protected by the hardmask  252 . The selective removal of the VEB mask layer  240  fully clears the first openings  231  and provide locations where full width vias may be patterned. 
     In a particular embodiment, the isotropic etching process is a timed etching process. For example, the etching process may be timed so that after the opening  231  is entirely cleared, the etching process is stopped. Since the sidewall surfaces of the VEB mask layer  240  are protected by the hardmask  252 , the use of a timed etch limits the removal from the top surface. However, due to the isotropic nature of the etching process, the top surfaces of the remaining portions of the VEB mask layer  240  may be recessed below a top surface of the hardmask  252  in some embodiments. 
     Referring now to  FIGS.  8 C and  8 D , a pair of plan view micrographs that depict the changes resulting from the selective removal of portions of the VEB mask layer  240  are shown, respectively, in accordance with an embodiment. In  FIG.  8 C , the narrow second openings  232  are clearly illustrated as the black rectangular shaped regions. The neighboring openings of the cross-grating are not clearly defined since they are filled by a combination of the VEB mask layer  240  and the hardmask  252 . In  FIG.  8 D , the micrograph depicts a semiconductor device after the VEB mask layer  240  is preferentially etched to fully reveal selected first openings  231 . As shown, the first openings  231  are significantly larger than the second openings  232  in  FIG.  8 C . Additionally, the etching process reveals the top surfaces of the first lines  221  and the second lines  222  of the cross-grating. The full reveal of the selected first openings  231  occurs without removing the VEB mask layer  240  and the hardmask  252  from neighboring locations in the cross-grating. 
     Referring now to  FIGS.  9 A and  9 B , a plan view illustration and a corresponding cross-sectional illustration along line B-B′ after the opening  231  is transferred into the substrate  206 / 205  are shown, respectively, in accordance with an embodiment. As shown, the residual portions of the VEB mask layer  240 , the hardmask  252 , and the first lines  221  and second lines  222  of the cross-grating provide protection to the underlying substrate  206  where a via opening is not desired. 
     Referring now to  FIGS.  10 A and  10 B , a perspective view illustration and a cross-sectional illustration after the second lines  222  and residual portions of the VEB mask layer  240  and the hardmask  252  are removed are shown, respectively, in accordance with an embodiment. In an embodiment, the VEB mask layer  240  and the hardmask  252  may be removed with one or more etching processes. The second lines  222  may then be removed to so that channels  244  between neighboring first lines  221  are provided. 
     Referring now to  FIGS.  10 C and  10 D , a plan view micrograph and a cross-sectional micrograph of a semiconductor device  200  corresponding to the illustrations in  FIGS.  10 A and  10 B  are shown, respectively, in accordance with an embodiment. In the plan view illustration in  FIG.  10 C , the first lines  221  and the openings  231  are clearly illustrated. As shown, the openings  231  have sidewalls that are defined by surfaces of the first lines  221 . Additionally, the openings  231  are substantially rectangular in shape due to the use of a cross-grating pattern to define the openings  231 . In  FIG.  10 D , the cross-sectional illustration illustrates that the profile of the first openings  231  and the first lines  221  need not be substantially rectangular. Due to processing conditions, the first lines  221  may develop a rounded top surface. Similarly, the openings  231  may exhibit a rounded bottom surface. Furthermore, due to processing non-uniformities, the profiles, widths, etc. of the openings  231  may exhibit some variability in width and/or pitch. 
     Referring now to  FIG.  11   , a cross-sectional illustration of the semiconductor device  200  after vias  273  and a second metal layer  275  are formed is shown, in accordance with an embodiment. The vias  273  and the second metal layer  275  may be deposited with any suitable process, such as electroplating, or the like. In an embodiment, the vias  273  provides electrical coupling between the first metal layer  203  and the second metal layer  275 . 
     Referring now to  FIGS.  12 A- 12 F , a plan view illustration and a series of cross-sectional illustrations depicting a process for forming a semiconductor device  300  that includes a VEB mask layer is shown, in accordance with an embodiment. 
     Referring now to  FIGS.  12 A and  12 B , a plan view illustration and a cross-sectional illustration of a semiconductor device  300  are shown, respectively, in accordance with an embodiment. As shown, the semiconductor device  300  may comprise a plurality of source/drain (S/D) contacts  371  and a plurality of gate contacts  372  arranged in a grid like pattern. That is, the S/D contacts  371  and the gate contacts  372  may be arranged in an alternating pattern. The S/D contacts  371  and the gate contacts  372  may be embedded in a first ILD layer  373 . 
     In an embodiment, top surfaces of the gate contacts  372  may be recessed below top surfaces of the S/D contacts  371 . Openings  377  may pass through a portion of the first ILD  373  to expose the top surfaces of the gate contacts  372 . In an embodiment, top surfaces of the S/D contacts  371  may also be covered by a hardmask layer  375 . 
     Referring now to  FIG.  12 C , a cross-sectional illustration of the semiconductor device  300  after a VEB mask layer  340  and a second ILD  374  are disposed over exposed surfaces is shown, in accordance with an embodiment. In an embodiment, the VEB mask layer  340  may be positioned over the S/D contacts  371 , the gate contacts  372 , and the first ILD  373 . The VEB mask layer  340  is a conformal layer. As such, the VEB mask layer  340  extends along sidewall surfaces of the openings  377 . The remaining volume of the openings  377  may be filled with the second ILD  374 . In an embodiment, a portion of the VEB mask layer  340  may be between the second ILD  374  and the S/D contact  371 . In an embodiment, the VEB mask layer  340  may be substantially similar to the VEB mask layers described above, with the exception that the VEB mask layer  340  is an insulative material. Accordingly, the VEB mask layer  340  may have a thickness T that is 10 nm or less or 5 nm or less, and the VEB mask layer  340  may comprise silicon and nitrogen (e.g., SiN), silicon and oxygen (e.g., SiO 2 ), or aluminum and oxygen (e.g., Al 2 O). 
     Referring now to  FIG.  12 D , a cross-sectional illustration after an opening  337  is formed into the second ILD  374  is shown, in accordance with an embodiment. In an embodiment, the opening  337  may be positioned above the gate contact  372 A. The opening  337  may result in a second opening  342  being cleared so that sidewalls of the VEB mask layer  340  are exposed. 
     Referring now to  FIG.  12 E , a cross-sectional illustration after the VEB mask layer  340  in the opening  337  is removed is shown, in accordance with an embodiment. In an embodiment, the VEB mask layer  340  may be removed with an isotropic etching process. Removal of the VEB mask layer  340  results in the opening  377  being cleared above the gate contact  372 A. In an embodiment, a width of the opening  377  is smaller than a width of the opening  337  that passes through the second ILD  374 . 
     Referring now to  FIG.  12 F , a cross-sectional illustration after a fill metal  378  is disposed in the opening  377  is shown, in accordance with an embodiment. In an embodiment, the fill metal  378  may be in direct contact with the gate contact  372 A. Furthermore, the fill metal  378  may also be in contact with portions of the VEB mask layer  340 . In an embodiment, the fill metal  378  may have a first width in the opening  377  and a second width that is greater than the first width through the second ILD  374 . In some embodiments, a portion of the fill metal  378  may be directly above the S/D contacts  371  that are adjacent to the gate contact  372 A. 
     Embodiments disclosed herein may be used to manufacture a wide variety of different types of integrated circuits and/or microelectronic devices. Examples of such integrated circuits include, but are not limited to, processors, chipset components, graphics processors, digital signal processors, micro-controllers, and the like. In other embodiments, semiconductor memory may be manufactured. Moreover, the integrated circuits or other microelectronic devices may be used in a wide variety of electronic devices known in the arts. For example, in computer systems (e.g., desktop, laptop, server), cellular phones, personal electronics, etc. The integrated circuits may be coupled with a bus and other components in the systems. For example, a processor may be coupled by one or more buses to a memory, a chipset, etc. Each of the processor, the memory, and the chipset, may potentially be manufactured using the approaches disclosed herein. 
       FIG.  13    illustrates a computing device  1300  in accordance with one implementation of an embodiment of the disclosure. The computing device  1300  houses a board  1302 . The board  1302  may include a number of components, including but not limited to a processor  1304  and at least one communication chip  1306 . The processor  1304  is physically and electrically coupled to the board  1302 . In some implementations the at least one communication chip  1306  is also physically and electrically coupled to the board  1302 . In further implementations, the communication chip  1306  is part of the processor  1304 . 
     Depending on its applications, computing device  1300  may include other components that may or may not be physically and electrically coupled to the board  1302 . These other components include, but are not limited to, volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flash memory, a graphics processor, a digital signal processor, a crypto processor, a chipset, an antenna, a display, a touchscreen display, a touchscreen controller, a battery, an audio codec, a video codec, a power amplifier, a global positioning system (GPS) device, a compass, an accelerometer, a gyroscope, a speaker, a camera, and a mass storage device (such as hard disk drive, compact disk (CD), digital versatile disk (DVD), and so forth). 
     The communication chip  1306  enables wireless communications for the transfer of data to and from the computing device  1300 . The term “wireless” and its derivatives may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that may communicate data through the use of modulated electromagnetic radiation through a non-solid medium. The term does not imply that the associated devices do not contain any wires, although in some embodiments they might not. The communication chip  1306  may implement any of a number of wireless standards or protocols, including but not limited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as any other wireless protocols that are designated as 3G, 4G, 5G, and beyond. The computing device  1300  may include a plurality of communication chips  1306 . For instance, a first communication chip  1306  may be dedicated to shorter range wireless communications such as Wi-Fi and Bluetooth and a second communication chip  1306  may be dedicated to longer range wireless communications such as GPS, EDGE, GPRS, CDMA, WiMAX, LTE, Ev-DO, and others. 
     The processor  1304  of the computing device  1300  includes an integrated circuit die packaged within the processor  1304 . In an embodiment, the integrated circuit die of the processor may comprise a BEOL stack that comprises one or more plugs and/or vias that are manufactured using a VEB mask layer, as described herein. The term “processor” may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory. 
     The communication chip  1306  also includes an integrated circuit die packaged within the communication chip  1306 . In an embodiment, the integrated circuit die of the communication chip m may comprise a BEOL stack that comprises one or more plugs and/or vias that are manufactured using a VEB mask layer, as described herein. 
     In further implementations, another component housed within the computing device  1300  may comprise a BEOL stack that comprises one or more plugs and/or vias that are manufactured using a VEB mask layer, as described herein. 
     In various implementations, the computing device  1300  may be a laptop, a netbook, a notebook, an ultrabook, a smartphone, a tablet, a personal digital assistant (PDA), an ultra mobile PC, a mobile phone, a desktop computer, a server, a printer, a scanner, a monitor, a set-top box, an entertainment control unit, a digital camera, a portable music player, or a digital video recorder. In further implementations, the computing device  1300  may be any other electronic device that processes data. 
       FIG.  14    illustrates an interposer  1400  that includes one or more embodiments of the disclosure. The interposer  1400  is an intervening substrate used to bridge a first substrate  1402  to a second substrate  1404 . The first substrate  1402  may be, for instance, an integrated circuit die. The second substrate  1404  may be, for instance, a memory module, a computer motherboard, or another integrated circuit die. In an embodiment, one or both of the first substrate  1402  and the second substrate  1404  may comprise a BEOL stack that comprises one or more plugs and/or vias that are manufactured using a VEB mask layer, in accordance with embodiments described herein. Generally, the purpose of an interposer  1400  is to spread a connection to a wider pitch or to reroute a connection to a different connection. For example, an interposer  1400  may couple an integrated circuit die to a ball grid array (BGA)  1406  that can subsequently be coupled to the second substrate  1404 . In some embodiments, the first and second substrates  1402 / 1404  are attached to opposing sides of the interposer  1400 . In other embodiments, the first and second substrates  1402 / 1404  are attached to the same side of the interposer  1400 . And in further embodiments, three or more substrates are interconnected by way of the interposer  1400 . 
     The interposer  1400  may be formed of an epoxy resin, a fiberglass-reinforced epoxy resin, a ceramic material, or a polymer material such as polyimide. In further implementations, the interposer may be formed of alternate rigid or flexible materials that may include the same materials described above for use in a semiconductor substrate, such as silicon, germanium, and other group III-V and group IV materials. 
     The interposer  1400  may include metal interconnects  1408  and vias  1410 , including but not limited to through-silicon vias (TSVs)  1412 . The interposer  1400  may further include embedded devices  1414 , including both passive and active devices. Such devices include, but are not limited to, capacitors, decoupling capacitors, resistors, inductors, fuses, diodes, transformers, sensors, and electrostatic discharge (ESD) devices. More complex devices such as radio-frequency (RF) devices, power amplifiers, power management devices, antennas, arrays, sensors, and MEMS devices may also be formed on the interposer  1400 . In accordance with embodiments of the disclosure, apparatuses or processes disclosed herein may be used in the fabrication of interposer  1400 . 
     Thus, embodiments of the present disclosure may comprise a BEOL stack that comprises one or more plugs, vias, and/or cuts that are manufactured using an edge placement error mitigation scheme, and the resulting structures. 
     The above description of illustrated implementations of embodiments of the disclosure, including what is described in the Abstract, is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. While specific implementations of, and examples for, the disclosure are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize. 
     These modifications may be made to the disclosure in light of the above detailed description. The terms used in the following claims should not be construed to limit the disclosure to the specific implementations disclosed in the specification and the claims. Rather, the scope of the disclosure is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation. 
     Example 1: a method of fabricating an interconnect layer over a substrate, comprising: forming a first grating of parallel first lines; forming a second grating of parallel second lines, wherein the second lines are substantially orthogonal to the first lines, and wherein the first lines and second lines define a plurality of first openings; disposing a conformal mask layer over the first lines and the second lines, wherein the conformal mask layer partially fills the first openings and defines a second opening within each of the first openings; disposing a hardmask over the conformal mask layer, wherein the hardmask fills the second openings; patterning third openings into the hardmask, wherein the third openings clear the hardmask from at least one of the second openings; and removing the mask layer proximate to cleared second openings to clear first openings. 
     Example 2: the method of Example 1, further comprising: recessing the hardmask after forming the third openings, wherein a top surface of the hardmask is below a top surface of the mask layer. 
     Example 3: the method of Example 2, wherein the mask layer is removed with an isotropic etching process. 
     Example 4: the method of Example 3, wherein the remaining portions of the hardmask protect lateral sidewall surfaces of the mask layer from the isotropic etching process. 
     Example 5: the method of Examples 1-4, further comprising: transferring a pattern of the cleared first openings into the substrate. 
     Example 6: the method of Example 5, further comprising: removing remaining portions of the hardmask, the mask layer, and the second lines. 
     Example 7: the method of Example 6, wherein a conductive material is disposed into the opening in the substrate to form a via. 
     Example 8: the method of Examples 1-7, wherein the mask layer has a thickness that is less than 5 nm. 
     Example 9: the method of Examples 1-8, wherein the mask layer comprises silicon and nitrogen, silicon and oxygen, aluminum and oxygen, or titanium and nitrogen. 
     Example 10: the method of Examples 1-9, wherein the first lines have a pitch of approximately 30 nm or less, and wherein the first lines have a width of approximately 12 nm or less. 
     Example 11: a method of fabricating an interconnect layer of over a semiconductor substrate, comprising: forming a cross-grating over a substrate; lining the cross-grating with a mask layer; disposing a hardmask over the mask layer; patterning an opening into the hardmask, wherein the opening exposes surfaces of the mask layer; and removing the exposed surfaces of the mask layer. 
     Example 12: the method of Example 11, further comprising: recessing the hardmask after the hardmask is patterned, wherein a top surface of the hardmask is below a top surface of the mask layer. 
     Example 13: the method of Example 11 or Example 12, wherein the exposed surfaces of the mask layer are removed with an isotropic etching process. 
     Example 14: the method of Example 13, wherein the isotropic etching process is a timed etch. 
     Example 15: the method of Examples 11-14, further comprising: patterning the substrate using the cross-grating, the mask layer, and the hardmask as an etching mask. 
     Example 16: the method of Examples 11-15, wherein the mask layer has a thickness that is approximately 5 nm or less. 
     Example 17: the method of Examples 11-16, wherein an overlay error margin for patterning the hardmask is approximately 10 nm or greater. 
     Example 18: the method of Examples 11-17, wherein the mask layer comprises silicon and nitrogen, silicon and oxygen, aluminum and oxygen, or titanium and nitrogen. 
     Example 19: the semiconductor device, comprising: a first interlayer dielectric (ILD); a grid of source/drain (S/D) contacts and gate contacts in the first ILD, wherein the gate contacts and the S/D contacts are arranged in an alternating pattern, and wherein top surfaces of the gate contacts are below top surfaces of the S/D contacts so that an opening defined by sidewall surfaces of the first ILD is positioned over each of the gate contacts; a mask layer partially filling a first opening over a first gate contact; and a fill metal filling a second opening over a second gate contact that is adjacent to the first gate contact. 
     Example 20: the semiconductor device of Example 19, wherein the openings over the gate contacts are substantially rectangular. 
     Example 21: the semiconductor device of Example 19 or Example 20, further comprising a second ILD, wherein the second ILD fills a remainder of the first opening not filled by the mask layer. 
     Example 22: the semiconductor device of Example 21, wherein the mask layer has a thickness that is approximately 5 nm or less. 
     Example 23: an electronic system, comprising: a board; and a die electrically coupled to the board, wherein the die comprises: a first interlayer dielectric (ILD); a first gate contact in the first ILD; a second gate contact in the first ILD; a mask layer over and in contact with the first ILD and a top surface of the first gate contact, wherein the mask layer is conformal and lines a first opening into the first ILD over the first gate contact; and a fill metal filling a second opening over the second gate contact, wherein the fill metal is in direct contact with a top surface of the second gate contact. 
     Example 24: the electronic system of Example 23, wherein a remaining portion of the first opening that is not filled by the mask layer is filled by a second ILD. 
     Example 25: the electronic system of Example 23 or Example 25, wherein a thickness of the mask layer is approximately 5 nm or less.