WO2022246836A1 - 金属线及其制作方法 - Google Patents

金属线及其制作方法 Download PDF

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Publication number
WO2022246836A1
WO2022246836A1 PCT/CN2021/096928 CN2021096928W WO2022246836A1 WO 2022246836 A1 WO2022246836 A1 WO 2022246836A1 CN 2021096928 W CN2021096928 W CN 2021096928W WO 2022246836 A1 WO2022246836 A1 WO 2022246836A1
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WIPO (PCT)
Prior art keywords
metal
trench
sacrificial layer
mask
manufacturing
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PCT/CN2021/096928
Other languages
English (en)
French (fr)
Inventor
陈江博
于海
孙拓
张硕
李泽源
梁魁
孟凡理
李延钊
Original Assignee
京东方科技集团股份有限公司
北京京东方技术开发有限公司
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Application filed by 京东方科技集团股份有限公司, 北京京东方技术开发有限公司 filed Critical 京东方科技集团股份有限公司
Priority to PCT/CN2021/096928 priority Critical patent/WO2022246836A1/zh
Priority to CN202180001375.8A priority patent/CN115917726A/zh
Priority to US17/775,714 priority patent/US20240153782A1/en
Publication of WO2022246836A1 publication Critical patent/WO2022246836A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
    • H01L21/321—After treatment
    • H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
    • H01L21/32139—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer using masks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838—Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76877—Filling of holes, grooves or trenches, e.g. vias, with conductive material
    • H01L21/7688—Filling of holes, grooves or trenches, e.g. vias, with conductive material by deposition over sacrificial masking layer, e.g. lift-off
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
    • H01L23/528—Geometry or layout of the interconnection structure
    • H01L23/5283—Cross-sectional geometry

Definitions

  • a method for manufacturing a metal wire which includes:
  • forming a metal bar on a substrate includes:
  • the photoresist pattern covers the metal material in the trench and exposes the metal material outside the trench;
  • the mask has a second cross-section perpendicular to the substrate along the width direction, and the second cross-section generally has a narrow top and a wide bottom.
  • an ashing stop layer is formed on the substrate first, and the sacrificial layer is formed on the ashing stop layer.
  • the metal material is filled in the groove by electroplating, and the metal material is not formed outside the groove.
  • the exposed part of the metal seed layer is removed synchronously or not.
  • a metal material is deposited, wherein the metal material formed over the sacrificial layer between the first trench and the second trench serves as the metal strip.
  • the sacrificial layer is made of a light-sensitive organic material, and the first groove and the second groove are formed by performing photolithography on the sacrificial layer.
  • the width of the first trench and/or the second trench is greater than or equal to 2 microns, and the slope of the sidewall of the first trench and/or the second trench is greater than Or equal to 80 degrees and less than or equal to 90 degrees.
  • a hard mask is first formed on the sacrificial layer, and the hard mask is corresponding to the first groove and the second groove. an opening is formed at the slot;
  • the material of the hard mask includes molybdenum, aluminum, indium tin oxide or indium gallium zinc oxide.
  • a metal wire manufactured according to the above manufacturing method is provided.
  • metal lines with high thickness and narrow line width can be formed, and the formed The uniformity of the wire throughout.
  • Fig. 1 is a schematic flow chart of a method for manufacturing a metal wire of the present application
  • FIGS. 2 to 9 are structural schematic diagrams of a manufacturing method provided by an embodiment of the present application.
  • 10 to 12 are schematic structural diagrams of a manufacturing method provided by yet another embodiment of the present application.
  • 18 to 20 are schematic structural diagrams of a manufacturing method provided by another embodiment of the present application.
  • 21 to 24 are schematic structural diagrams of a manufacturing method provided by another embodiment of the present application.
  • 25 to 27 are schematic structural diagrams of a manufacturing method provided by another embodiment of the present application.
  • S20 forming a mask above the metal bar, the width of the mask is smaller than the width of the metal bar, and along the width direction, the mask covers the upper surface of the middle region of the metal bar, while exposing the upper surface of the edge region of the metal bar;
  • the emergence of etching saturation state is the result of the joint effect of the special positional relationship between the mask and the metal line block, and the surface tension and diffusion of the etching solution causing lateral etching to slow down.
  • the above process is relatively stable, that is, after reaching the etching saturation state, the line width of the metal line is basically kept at the same level available for production, and the etching results obtained by different batches are also basically stable. .
  • the above method can obtain a metal strip with high thickness and narrow line width, and the line width uniformity of the metal strip is high.
  • the continuous etching can no longer consume a single bit of the metal bar, but that the etching rate obtained by continuing etching will be much weaker than the etching rate in the previous stable etching stage , so even if the etching continues for a limited period of time, the impact on the final etching result of the metal strip is very weak.
  • the etching speed is significantly lower than the speed or average speed of the previous stable etching stage, for example, less than one-third of the average speed of the stable etching stage, it can be considered that the etching is in a saturated state.
  • a substrate 1 is provided, and the substrate 1 is glass. In other embodiments, the substrate can also be other rigid substrates or flexible substrates.
  • a sacrificial layer 2 is formed on the substrate 1 , and a groove G is formed in the sacrificial layer 2 .
  • the material of the sacrificial layer 2 is a light-sensitive organic material, and its photolithography (including exposure, development, etc.) can form a groove G inside it, and the groove G runs through the sacrificial layer in the thickness direction. .
  • the material of the sacrificial layer can also be other organic materials or inorganic materials, as long as it is convenient to form the groove G inside, and the sacrificial layer can be easily removed in the subsequent process.
  • the first cross-sectional shape of the formed groove G is an isosceles trapezoid with a wide top and a narrow bottom. Wherein, the first section extends along the width direction of the trench G and is perpendicular to the upper surface of the substrate 1 .
  • the first cross-section of the trench can also have other shapes, but when the overall shape of the trench is wide at the top and narrow at the bottom, the finally obtained metal strip has good shape stability and narrow line width. have better performance.
  • the width of the top of the trench G (ie, the width at the widest point) is about 7 microns ( ⁇ m)
  • the width of the bottom of the trench G (ie, the width at the narrowest point) is about 4.5 microns ( ⁇ m)
  • the thickness (ie depth) of the groove G is about 5 microns ( ⁇ m).
  • the present application is not limited thereto, as long as the thickness of the groove G is greater than the final required thickness of the metal line.
  • the above-mentioned groove with the first cross-section of the isosceles trapezoid can be formed by a photolithography process and by precisely controlling the parameters of the photolithography. It is also possible to form the above-mentioned groove with the first cross-section of an isosceles trapezoid by stamping.
  • a stamper can be designed, the stamper has a raised portion, and the shape of the raised portion is the same as that of the groove; then, the raised portion of the stamper is pressed into the sacrificial layer and then pulled out , a groove corresponding to the shape can be formed in the sacrificial layer.
  • the groove G is filled with the photoresist 4 , and the excess photoresist 4 is also formed on the metal material layer 3 outside the groove G.
  • the upper surface of the photoresist 4 is flat as a whole.
  • the entire surface of the photoresist 4 is ashed with oxygen plasma (O 2 plasma).
  • O 2 plasma oxygen plasma
  • wet etching is performed to remove the metal material outside the trench G.
  • all metal materials outside the groove G can be removed in about 360 seconds.
  • other methods can also be used to remove the metal material outside the trench G, such as dry etching, chemical mechanical polishing (CMP) and so on.
  • a mask 5 is formed on the metal strip 34 .
  • the width of the mask 5 is smaller than the width of the metal strip 34, and the orthographic projection of the mask 5 on the substrate 1 is located at the orthographic projection of the metal strip 34 on the substrate 1 In this width direction, the mask 5 covers the upper surface of the middle region of the metal strip 34 and exposes the upper surface of the edge region of the metal strip 34 .
  • the width of the mask 5 can be designed to be 4 microns to 6 microns larger than the width of the final required metal line, that is, both side walls of the mask 5 in the width direction are larger than the width of the final required metal line. The sidewalls protrude outward by 2 microns to 3 microns.
  • the width of the mask is smaller than the width of the metal strip
  • the width of the masks or metal bars
  • the widths of the masks are not the same throughout the implementation process, it is not required that the widths of the masks be smaller than the widths of the metal bars. For example, as long as the width of the lower surface of the mask is smaller than the width of the upper surface of the metal bar, it can be considered that "the width of the mask is smaller than the width of the metal bar”.
  • the mask 5 is a photoresist pattern formed after the photoresist is exposed and developed (ie, photolithography).
  • the mask may also be a hard mask or other film layers, as long as it can protect the upper surface of the metal strip 34 to a certain extent in the subsequent wet etching process.
  • the second section of the mask 5 is an isosceles trapezoid with a narrow top and a wide bottom. Wherein, the second section extends along the width direction of the mask 5 and is perpendicular to the upper surface of the substrate 1.
  • the second cross-sectional shape of the mask 5 is not limited thereto. For example, it may be a rectangle, a non-isosceles trapezoid, or the like.
  • the second cross-section of the mask 5 adopts a shape with a narrow top and a wide bottom, it is more conducive to obtaining metal strips with narrower line widths in the subsequent wet etching process.
  • the above-mentioned mask 5 having the second cross-section of an isosceles trapezoid can be formed by a photolithography process and by precisely controlling the parameters of the photolithography.
  • the above-mentioned mask 5 having the second isosceles trapezoidal cross-section can also be formed by stamping.
  • a stamper can be designed, the pressing surface of the stamper has pits, and the shape of the pits is the same as that of the mask 5; Then pull out the glue, and the photoresist can be pressed to form a mask 5.
  • the metal strips 34 are wet-etched to a saturated state to form metal lines 36, the width of which is smaller than that of the mask. Die 5 width.
  • the width (ie, line width) of the finally obtained metal line 36 is about 1.5 microns ( ⁇ m).
  • the appearance of etching saturation state is due to the special positional relationship between the mask 5 and the metal strip 34, as well as the surface tension and diffusion of the etching solution resulting in the combined effect of slowing down the lateral etching. .
  • the above process is relatively stable, that is, after reaching the etching saturation state, the line width of the metal line is basically kept at the same level available for production, and the etching results obtained by different batches are also basically stable. . Taking advantage of this point, the above method can obtain metal lines 36 with high thickness and narrow line width, and the line width uniformity of the metal lines 36 is high.
  • the metal strip 34 can no longer be consumed by further etching, but it just means that the etching rate obtained by continuing etching will be much weaker than that of the previous stable etching stage. Therefore, even if the etching continues for a limited period of time, the impact on the final etching result of the metal strip 34 is very weak. For example, when the etching speed is significantly lower than the speed or average speed of the previous stable etching stage, for example, less than one-third of the average speed of the stable etching stage, it can be considered that the etching is in a saturated state.
  • the etching slope on the side of the metal material is about 45 degrees, which is caused by the difference in etching rate between the upper and lower surfaces of the metal material.
  • the contact between the upper and lower sides of the side and the etching solution is basically consistent, so the difference in etching rate between the upper and lower sides of the side is small, Finally, a metal line structure with narrow line width and large thickness can be realized.
  • FIG. 10 to FIG. 12 disclose another specific embodiment of the above metal wire manufacturing method. This embodiment is similar to the embodiment shown in FIG. 2 to FIG. 9 , the only difference is that substrates of different materials are used, and the substrates are treated accordingly before forming the sacrificial layer.
  • the material of the substrate is COP optical material. That is, the substrate is a COP substrate 7 .
  • the optical material COP has the following characteristics: high transparency, low birefringence, low water absorption, high rigidity, high heat resistance, good water vapor air tightness, and meets FDA (US Food and Drug Administration) standards.
  • an ashing stop layer 6 may be formed on the COP substrate 7 .
  • the material of the ashing stop layer 6 may be silicon nitride (SiN) or silicon oxide (SiO).
  • the ashing barrier layer 6 may have a thickness of 100 nanometers (nm).
  • the ashing barrier layer 6 can be deposited by plasma enhanced chemical vapor deposition (PECVD).
  • PECVD plasma enhanced chemical vapor deposition
  • a sacrificial layer 2 is formed on the ashing stop layer 6 , and grooves are formed in the sacrificial layer 2 .
  • a metal material is deposited on the sacrificial layer 2 , and the metal material layer 3 formed by deposition is formed on the sacrificial layer 2 and also fills the groove, but does not fill the groove.
  • the trench is filled with photoresist 4 , and excess photoresist 4 is also formed on the metal material layer 3 outside the trench.
  • the upper surface of the photoresist 4 is flat as a whole.
  • the entire surface of the photoresist 4 is ashed with oxygen plasma (O 2 plasma).
  • the photoresist 4 outside the trench is completely removed, but the photoresist 4 (photoresist pattern) remains on the metal material layer 3 inside the trench.
  • wet etching is performed to remove the metal material outside the trench. And remove the photoresist 4 remaining above the metal material in the trench.
  • the metal material remaining in the trench at this time is the metal strip 34 to be further etched subsequently.
  • FIG. 13 to FIG. 17 disclose yet another specific embodiment of the above metal wire manufacturing method.
  • a substrate 1 is provided, and the substrate 1 is glass. In other embodiments, the substrate can also be other rigid substrates or flexible substrates.
  • a metal seed layer 8 is first deposited on the substrate 1 .
  • the material of the metal seed layer 8 can be copper, and the thickness can be 4000 angstroms The pre-formed metal seed layer 8 can facilitate the subsequent electroplating process.
  • a sacrificial layer 2 is formed on the metal seed layer 8 and grooves are formed in the sacrificial layer 2 .
  • the material of the sacrificial layer 2 is an organic material sensitive to light, and a groove can be formed inside it by photolithography (including exposure, development, etc.), and the groove penetrates the sacrificial layer in the thickness direction, and The metal seed layer is exposed.
  • the material of the sacrificial layer can also be other organic materials or inorganic materials, as long as it is convenient to form a groove inside and remove the sacrificial layer in a subsequent process.
  • the first cross-sectional shape of the formed trench is an isosceles trapezoid with a wide top and a narrow bottom.
  • the sacrificial layer 2 can be removed by ashing with oxygen plasma (O 2 plasma). After the sacrificial layer 2 is removed, the sidewalls of the metal strips 34 are exposed. The width of the upper surface of the metal strip 34 is slightly smaller than the width of the upper end of the groove G, which is slightly smaller than 7 microns ( ⁇ m). The resulting structure is shown in FIG. 15 .
  • a mask 5 is formed on the metal strip 34 .
  • the width of the mask 5 is smaller than the width of the metal strip 34, and the orthographic projection of the mask 5 on the substrate 1 is located at the orthographic projection of the metal strip 34 on the substrate 1 In this width direction, the mask 5 covers the upper surface of the middle region of the metal strip 34 and exposes the upper surface of the edge region of the metal strip 34 .
  • the width of the mask 5 can be designed to be 4 microns to 6 microns larger than the width of the final required metal line, that is, both side walls of the mask 5 in the width direction are larger than the width of the final required metal line. The sidewalls protrude outward by 2 microns to 3 microns.
  • the mask 5 is a photoresist pattern formed after the photoresist is exposed and developed (ie, photolithography).
  • the mask may also be a hard mask or other film layers, as long as it can protect the upper surface of the metal strip 34 to a certain extent in the subsequent wet etching process.
  • the second section of the mask 5 is an isosceles trapezoid with a narrow top and a wide bottom. Wherein, the second section extends along the width direction of the mask 5 and is perpendicular to the upper surface of the substrate 1 .
  • the second cross-sectional shape of the mask 5 is not limited thereto. For example, it may be a rectangle, a non-isosceles trapezoid, or the like.
  • the second cross-section of the mask 5 adopts a shape with a narrow top and a wide bottom, it is more conducive to obtaining metal strips with narrower line widths in the subsequent wet etching process.
  • the metal strips 34 are wet etched to a saturated state to form metal lines 36, the width of the metal lines 36 is smaller than that of the mask 5. width.
  • the width (ie, line width) of the finally obtained metal line 36 is about 1.5 microns ( ⁇ m).
  • the appearance of etching saturation state is due to the special positional relationship between the mask 5 and the metal strip 34, as well as the surface tension and diffusion of the etching solution resulting in the combined effect of slowing down the lateral etching. .
  • the above process is relatively stable, that is, after reaching the etching saturation state, the line width of the metal line is basically kept at the same level available for production, and the etching results obtained by different batches are also basically stable. . Taking advantage of this point, the above method can obtain metal lines 36 with high thickness and narrow line width, and the line width uniformity of the metal lines 36 is high.
  • the metal strip 34 can no longer be consumed by further etching, but it just means that the etching rate obtained by continuing etching will be much weaker than that of the previous stable etching stage. Therefore, even if the etching continues for a limited period of time, the impact on the final etching result of the metal strip 34 is very weak. For example, when the etching speed is significantly lower than the speed or average speed of the previous stable etching stage, for example, less than one-third of the average speed of the stable etching stage, it can be considered that the etching is in a saturated state.
  • a sacrificial layer 2 is formed on the substrate 1, and a first trench T1 and a second trench T2 are formed in the sacrificial layer 2, and the first trench T1 and the second trench T2 are isolated from each other.
  • the material of the sacrificial layer 2 is an organic material sensitive to light, and its photolithography (including exposure, development, etc.) can synchronously form the first trench T1 and the second trench T2 inside it.
  • the groove T1 and the second trench T2 penetrate the sacrificial layer in a thickness direction.
  • the material of the sacrificial layer can also be other organic materials or inorganic materials, as long as it is convenient to form the first trench T1 and the second trench T2 inside it, and the sacrificial layer can be easily removed in the subsequent process. Can.
  • the cross-sectional shapes of the first trench T1 and the second trench T2 formed can be rectangular, and the slopes of the side walls of the first trench T1 and the second trench T2 are relatively steep, ranging from 80 degrees (including the original number) to 90 degrees ( Inclusive of this number). Underdevelopment after exposure can be used to increase and achieve steeper slopes.
  • the first groove and the second groove can also be formed by pressing with a die, and their slopes can be guaranteed.
  • the width of the first trench T1 and the second trench T2 is more than 2 micrometers ( ⁇ m) (including 2 micrometers), and the thickness (depth) is more than 1 micrometer (including 1 micrometer), it is beneficial to realize the first The metal deposited in the groove and the second groove is not adhered to the metal outside the first groove and the second groove, which is beneficial to the quality of the finally formed metal wire.
  • the metal material is deposited on the sacrificial layer 2, and the deposited thickness meets the design and production requirements. It can be deposited by DC sputtering or vapor deposition, and the deposited metal can be a metal material with high conductivity such as aluminum (Al), copper (Cu) or silver (Ag). In the embodiment shown in the figures, the deposited metal material is aluminum with a thickness of about 2 micrometers ([mu]m).
  • the deposited metal material layer 9 is not only formed on the sacrificial layer 2 but also filled in the first trench T1 and the second trench T2. As a preferred implementation manner, the metal material layer 9 preferably does not fill up the first trench T1 and the second trench T2.
  • the metal material above the sacrificial layer 2 between the first trench T1 and the second trench T2 is used as a metal strip 34 , as shown in FIG. 22 , the metal strip 34 is not adhered to the metal material layer 9 in other regions.
  • the second section of the mask 5 is an isosceles trapezoid with a narrow top and a wide bottom. Wherein, the second section extends along the width direction of the mask 5 and is perpendicular to the upper surface of the substrate 1 .
  • the second cross-sectional shape of the mask 5 is not limited thereto. For example, it may be a rectangle, a non-isosceles trapezoid, or the like.
  • the second cross-section of the mask 5 adopts a shape with a narrow top and a wide bottom, it is more conducive to obtaining metal strips with narrower line widths in the subsequent wet etching process.
  • the metal strip 34 can no longer be consumed by further etching, but it just means that the etching rate obtained by continuing etching will be much weaker than that of the previous stable etching stage. Therefore, even if the etching continues for a limited period of time, the impact on the final etching result of the metal strip 34 is very weak. For example, when the etching speed is significantly lower than the speed or average speed of the previous stable etching stage, for example, less than one-third of the average speed of the stable etching stage, it can be considered that the etching is in a saturated state.
  • the etching slope on the side of the metal material is about 45 degrees, which is caused by the difference in etching rate between the upper and lower surfaces of the metal material.
  • the contact between the upper and lower sides of the side and the etching solution is basically consistent.
  • the etch rate difference is small, and finally a metal line structure with narrow line width and large thickness can be realized.
  • a hard mask 10 is first formed on the sacrificial layer 2, and the hard mask 10 corresponds to the first groove and the first groove. An opening is formed at the second groove.
  • the material of the hard mask 10 may be molybdenum (Mo), aluminum (Al), indium tin oxide (ITO) or indium gallium zinc oxide (IGZO).
  • Mo molybdenum
  • Al aluminum
  • ITO indium tin oxide
  • IGZO indium gallium zinc oxide
  • the etching selectivity ratio between the hard mask 10 and the sacrificial layer 2 is relatively large.
  • the hard mask 10 is an indium tin oxide film layer with a thickness of 1350 angstroms.
  • the sacrificial layer 2 is dry etched by using the hard mask 10 to form a first trench T1 and a second trench T2 in the sacrificial layer 2 . Since the etching options of the two are relatively large, the first trench T1 and the second trench T2 can be guaranteed to have excellent precision in the above-mentioned dry etching, and the sidewalls of the first trench T1 and the second trench T2 are Slopes can be better achieved.
  • the present application also provides a metal wire, which can be manufactured by any of the above-mentioned manufacturing methods.
  • the metal wires can be applied to display devices, on-screen antennas on mobile terminals, photonic chips, gratings, polarization, and the like.

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Abstract

本申请提供一种金属线及其制作方法。所述金属线的制作方法包括：在衬底上形成金属条块；在金属条块的上方形成掩模，所述掩模的宽度小于所述金属条块的宽度，且所述掩模在所述衬底上的正投影位于所述金属条块在所述衬底上的正投影内；在所述掩模的保护下，湿法刻蚀所述金属条块至饱和状态，以形成金属线，所述金属线的宽度小于所述掩模的宽度。上述制作方法可形成高厚度、窄线宽的金属线。

Description

金属线及其制作方法 技术领域
本公开涉及半导体技术领域，尤其涉及一种金属线及其制作方法。
背景技术
在半导体器件日益小型化的趋势下，领域内普遍面临的一个难点是制备用于信号传输的高厚度、窄线宽的金属线。金属线的材料通常是铝(Al)和铜(Cu)，在刻蚀过程中，它们的刻蚀坡度(profile)大约为45度左右。对于设计厚度为1.5微米(μm)以上(含1.5微米)的金属线，通常的刻蚀工艺无法保证刻蚀的均匀性。
常用曝光机的曝光线宽为3微米(μm)以上，通过直接增加过刻的方法所获得的高厚度、窄线宽金属线，不能保证线宽的均匀性。采用两次沉积金属两次图案化的工艺，会导致所获得金属截面不规则、不均匀，且有严重的光刻胶脱落问题。采用小沟槽内外延无机材料，比如氮化硅(SiN)或氧化硅(SiO)，而后蒸镀或电镀金属材料至小沟槽内，则有严重的线宽和厚度不均匀性缺陷。
因而，有必要对上述缺陷和问题进行改进。
发明内容
根据本申请实施例的第一方面，提供了一种金属线的制作方法，其包括：
在衬底上形成金属条块；
在金属条块的上方形成掩模，所述掩模的宽度小于所述金属条块的宽度，且所述掩模在所述衬底上的正投影位于所述金属条块在所述衬底上的正投影内；
在所述掩模的保护下，湿法刻蚀所述金属条块至饱和状态，以形成金属线，所述金属线的宽度小于所述掩模的宽度。
在一个实施例中，在衬底上形成金属条块，包括：
在衬底上形成牺牲层，所述牺牲层内形成有沟槽；
在所述沟槽内填充金属材料；
去除所述牺牲层。
在一个实施例中，所述牺牲层的材质为对光敏感的有机材料，通过对所述牺牲层进行光刻形成所述沟槽，通过灰化的方式去除所述牺牲层。
在一个实施例中，所述沟槽在沿所述宽度方向上具有垂直于所述衬底的第一截面，所述第一截面整体呈上宽下窄的形貌。
在一个实施例中，所述沟槽的所述第一截面为等腰梯形。
在一个实施例中，在所述沟槽内填充金属材料，包括：
在所述牺牲层上和所述沟槽内沉积金属材料；
形成光刻胶图案，所述光刻胶图案遮盖所述沟槽内的金属材料，而暴露所述沟槽外的金属材料；
在所述光刻胶图案的保护下刻蚀金属材料，以去除所述沟槽外的金属材料。
在一个实施例中，所述掩模在沿所述宽度方向上具有垂直于所述衬底的第二截面，所述第二截面整体呈上窄下宽的形貌。
在一个实施例中，所述掩模的所述第二截面为等腰梯形。
在一个实施例中，所述衬底包括COP光学材料；
在衬底上形成牺牲层之前，先在所述衬底上形成灰化阻挡层，所述牺牲层形成在所述灰化阻挡层上。
在一个实施例中，所述灰化阻挡层的材质包括氮化硅或者氧化硅。
在一个实施例中，在衬底上形成牺牲层之前，先在所述衬底上形成金属种子层，所述牺牲层形成在所述金属种子层，在所述牺牲层内形成的所述沟槽暴露所述金属种子层；
通过电镀的方式在所述沟槽内填充金属材料，且所述金属材料不形成在所述沟槽外。
在一个实施例中，在湿法刻蚀所述金属条块以形成金属线的过程中，所述金属种子层外露的部分被同步去除或未被同步去除。
在一个实施例中，在衬底上形成金属条块，包括：
在衬底上形成牺牲层；
在所述牺牲层内形成第一沟槽和第二沟槽，所述第一沟槽和所述第二沟槽相互隔离，并沿所述宽度方向排列；
沉积金属材料，其中形成在所述第一沟槽和所述第二沟槽之间的所述牺牲层上方的金属材料作为所述金属条块。
在一个实施例中，所述牺牲层的材质为对光敏感的有机材料，通过对所述牺牲层进行光刻形成所述第一沟槽和所述第二沟槽。
在一个实施例中，所述第一沟槽和/或所述第二沟槽的宽度大于或等于2微米，所述第一沟槽和/或所述第二沟槽的侧壁的坡度大于或等于80度并且小于或等于90度。
在一个实施例中，在形成第一沟槽和第二沟槽之前，先在所述牺牲层上形成硬掩膜，所述硬掩膜在对应所述第一沟槽和所述第二沟槽处形成有开 口；
利用所述硬掩膜对所述牺牲层进行干法刻蚀，以在所述牺牲层内形成第一沟槽和第二沟槽。
在一个实施例中，在沉积金属材料之前，去除所述硬掩膜。
在一个实施例中，所述硬掩膜的材质包括钼、铝、氧化铟锡或者铟镓锌氧化物。
根据本申请实施例的第二方面，提供了一种根据上述制作方法所制得的金属线。
本申请实施例所达到的主要技术效果是：
通过先在金属条块的上方形成特定的掩模，而后湿法刻蚀所述金属条块至饱和状态以形成金属线，既可形成高厚度、窄线宽的金属线，又保证了所形成金属线在各处的均匀性。
附图说明
图1是本申请一种金属线的制作方法的流程示意图；
图2至图9是本申请一实施例提供的制作方法的结构示意图；
图10至图12是本申请再一实施例提供的制作方法的结构示意图；
图13至图17是本申请又一实施例提供的制作方法的结构示意图；
图18至图20是本申请另一实施例提供的制作方法的结构示意图；
图21至图24是本申请再一实施例提供的制作方法的结构示意图；
图25至图27是本申请又一实施例提供的制作方法的结构示意图。
具体实施方式
这里将详细地对示例性实施例进行说明，其示例表示在附图中。下面 的描述涉及附图时，除非另有表示，不同附图中的相同数字表示相同或相似的要素。以下示例性实施例中所描述的实施例并不代表与本申请相一致的所有实施例。相反，它们仅是与如所附权利要求书中所详述的、本申请的一些方面相一致的装置和方法的例子。
在本申请使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。还应当理解，本文中使用的术语“和/或”是指并包含一个或多个相关联的列出项目的任何或所有可能组合。
应当理解，尽管在本申请可能采用术语第一、第二、第三等来描述各种信息，但这些信息不应限于这些术语。这些术语仅用来将同一类型的信息彼此区分开。例如，在不脱离本申请范围的情况下，第一信息也可以被称为第二信息，类似地，第二信息也可以被称为第一信息。取决于语境，如在此所使用的词语“如果”可以被解释成为“在……时”或“当……时”或“响应于确定”。
下面结合附图，对本申请实施例进行详细说明。在不冲突的情况下，下述的各实施例中的特征可以相互补充或相互组合。
本申请提供了一种金属线的制作方法。如图1所示，所述制作方法可包括以下步骤：
S10：在衬底上形成金属条块；
S20：在金属条块的上方形成掩模，所述掩模的宽度小于所述金属条块的宽度，在沿宽度方向上，所述掩模遮盖所述金属条块的中间区域的上表面，而暴露所述金属条块的边缘区域的上表面；
S30：在所述掩模的保护下，湿法刻蚀所述金属条块至饱和状态，以形成金属线，所述金属线的宽度小于所述掩模的宽度。
在上述刻蚀中，随着刻蚀的不断推进，会出现刻蚀饱和的状态。到达刻蚀饱和状态后，即便再大幅增加刻蚀时间，也无法明显改变对金属条块的刻蚀结果，无法获得更小的线宽。
在上述刻蚀过程中，刻蚀饱和状态的出现是由于所述掩模和金属线块之间的特殊位置关系以及刻蚀液表面张力和扩散造成侧向刻蚀减慢共同作用的结果。并且，上述过程是相对稳定的，即：到达刻蚀饱和状态后，金属线各处的线宽基本保持在生产可用的同一水平内，并且，不同批次所获得的刻蚀结果也是基本稳定的。正式利用此点，上述方法可获得高厚度、窄线宽的金属条，且所述金属条的线宽均匀性高。
说明一点，到达饱和状态后，并不意味着继续刻蚀不再能消耗金属条块的一丝一毫，只是代表继续刻蚀所可收获的刻蚀速度将大大弱于前面稳定刻蚀阶段的刻蚀速度，因而即便继续刻蚀有限的一段时间对金属条块最终刻蚀结果的影响也极微弱。例如，当刻蚀速度明显小于前面稳定刻蚀阶段的速度或平均速度时，比如小于稳定刻蚀阶段平均速度的三分之一时，即可认为已处于刻蚀饱和状态了。
在具体实施时，所述在衬底上形成金属条块的步骤S10，可以包括以下步骤：在衬底上形成牺牲层，所述牺牲层内形成有沟槽；在所述沟槽内填充金属材料；去除所述牺牲层。
图2至图9公开了上述金属线制作方法的一个具体实施例。
如图2，提供衬底1，所述衬底1为玻璃，在其它实施例中，衬底也可为其它硬性衬底或柔性衬底。在衬底1形成牺牲层2，并在所述牺牲层2内形成沟槽G。所述牺牲层2的材质为对光敏感的有机材料，对其光刻(包括曝光、显影等)即可在其内部形成沟槽G，所述沟槽G在厚度方向上贯穿所述牺牲层。在其它实施例中，牺牲层的材质也可为其它有机材料或无机材料，只要方便在其内部形成沟槽G，并在后续过程中可方便去除该牺牲层即可。 所形成的沟槽G的第一截面形状为上宽下窄的等腰梯形。其中，所述第一截面沿沟槽G的宽度方向延伸，并垂直于衬底1的上表面。在其它实施例中，沟槽的第一截面也可为其它形貌，但当其整体呈上宽下窄的形貌时，最终所获得的金属条在形貌稳定性和窄线宽方面都有更佳的性能。在图中实施例中，沟槽G顶部的宽度(即最宽处的宽度)约为7微米(μm)，沟槽G底部的宽度(即最窄处的宽度)约为4.5微米(μm)，沟槽G的厚度(即深度)约为5微米(μm)。当然，本申请不受限于此，只要沟槽G的厚度大于最终所需金属线的厚度即可。
可通过光刻工艺并精确控制光刻的参数来形成上述具有等腰梯形状第一截面的沟槽。也可通过压模压印的方式来形成上述具有等腰梯形状第一截面的沟槽。比如，可设计一种压模，该压模具有凸起部，所述凸起部的形貌与沟槽的形貌相同；而后，将该压模的凸起部压入牺牲层而后拔出，即可在牺牲层内形成对应形貌的沟槽。
在牺牲层2上沉积金属材料，所沉积的厚度满足设计和生产需求。可利用直流式溅镀或蒸镀的方式来沉积，所沉积的金属可以是铝(Al)、铜(Cu)或者银(Ag)等高电导率的金属材料。在图中所示实施例中，所沉积金属材料是铝，厚度约为2微米(μm)。如图2中所示，沉积所形成的金属材料层3既形成在牺牲层2上，也填充在沟槽G内，但未填满沟槽G。
如图3，利用光刻胶4填满沟槽G，多余的光刻胶4也会形成在沟槽G外的金属材料层3。光刻胶4的上表面整体平坦。随后，以氧等离子体(O 2plasma)灰化处理光刻胶4的整个表面。通过控制灰化处理的时间，使沟槽G外的光刻胶4被完全去除，但沟槽G内的金属材料层3上仍保留有光刻胶4(光刻胶图案)。所形成的结构如图4所示。
如图5，进行湿法刻蚀，以去除沟槽G外的金属材料。以图中实施例中2微米厚度的铝金属为例，大约360秒即可去除沟槽G外的所有金属材料。在其它实施例中，也可采用其它方式去除沟槽G外的金属材料，比如干法刻 蚀、化学机械研磨(CMP)等。
随后可去除残留在沟槽G内金属材料上方的光刻胶4。此时仍留在沟槽G内的金属材料，为方便描述，可称之为金属条块34。在图中实施例中，由于沟槽G的存在，金属条块34的截面形貌在整体上也呈上宽下窄状，具体为等腰梯形。
如图6，可采用氧等离子体(O 2plasma)灰化处理牺牲层2，以将其去除。牺牲层2去除后，金属条块34的侧壁暴露在外。金属条块34上表面的宽度略小于沟槽G上端的宽度，略小于7微米(μm)。所形成的结构如图7所示。
如图8，在金属条块34上形成掩模5。所述掩模5的宽度小于所述金属条块34的宽度，且所述掩模5在所述衬底1上的正投影位于所述金属条块34在所述衬底1上的正投影内，使得在沿该宽度方向上，所述掩模5遮盖所述金属条块34的中间区域的上表面，而暴露所述金属条块34的边缘区域的上表面。具体实施时，掩模5的宽度可被设计为比最终所需金属线的宽度大4微米到6微米，即掩模5在所述宽度方向上的两侧壁均比最终所需金属线的侧壁多向外凸伸2微米到3微米。
这里所说的“掩模的宽度小于金属条块的宽度”，主要比较的是两者接触面或邻近表面的宽度。由于在具体实施过程中，掩模(或金属条块)各处的宽度并不相同，并不要求掩模各处的宽度都要小于金属条块各处的宽度。比如，只要掩模下表面的宽度小于金属条块上表面的宽度，就可认为满足了“掩模的宽度小于金属条块的宽度”。
所述掩模5是光刻胶曝光、显影后(即，光刻)所形成的光刻胶图案。在其它实施例中，掩模也可以是硬掩膜或其它膜层，只要其在后续的湿法刻蚀工艺中能对金属条块34的上表面起到一定程度的保护作用即可。
在图中实施例中，所述掩模5的第二截面为上窄下宽的等腰梯形。其 中，所述第二截面沿掩模5的宽度方向延伸，并垂直于衬底1的上表面。当然，掩模5的第二截面形状不限于此。比如，可以是矩形、非等腰梯形等。但是，掩模5的第二截面采用上窄下宽的形貌时，可更有利于在后续湿法刻蚀工艺中获得更窄线宽的金属条。可通过光刻工艺并精确控制光刻的参数来形成上述具有等腰梯形状第二截面的掩模5。也可通过压模压印的方式来形成上述具有等腰梯形状第二截面的掩模5。比如，可设计一种压模，该压模的抵压面具有凹坑，所述凹坑的形貌与掩模5的形貌相同；而后，将该压模的抵压面压入光刻胶而后拔出，即可压迫光刻胶形成掩模5。
而后在所述掩模5的保护下，请参图8和图9，湿法刻蚀所述金属条块34至饱和状态，以形成金属线36，所述金属线36的宽度小于所述掩模5的宽度。最终获得的金属线36的宽度(即线宽)约为1.5微米(μm)。
在上述刻蚀中，随着刻蚀的不断推进，会出现刻蚀饱和的状态。到达刻蚀饱和状态后，即便再大幅增加刻蚀时间，也无法明显改变对金属条块34的刻蚀结果，无法获得更小的线宽。
在上述刻蚀过程中，刻蚀饱和状态的出现是由于所述掩模5和金属条块34之间的特殊位置关系以及刻蚀液表面张力和扩散造成侧向刻蚀减慢共同作用的结果。并且，上述过程是相对稳定的，即：到达刻蚀饱和状态后，金属线各处的线宽基本保持在生产可用的同一水平内，并且，不同批次所获得的刻蚀结果也是基本稳定的。正式利用此点，上述方法可获得高厚度、窄线宽的金属线36，且所述金属线36的线宽均匀性高。
说明一点，到达饱和状态后，并不意味着继续刻蚀不再能消耗金属条块34的一丝一毫，只是代表继续刻蚀所可收获的刻蚀速度将大大弱于前面稳定刻蚀阶段的刻蚀速度，因而即便继续刻蚀有限的一段时间对金属条块34最终刻蚀结果的影响也极微弱。例如，当刻蚀速度明显小于前面稳定刻蚀阶段的速度或平均速度时，比如小于稳定刻蚀阶段平均速度的三分之一时，即可认为已处于刻蚀饱和状态了。
相关技术对金属材料的刻蚀中，金属材料侧面的刻蚀坡度约为45度，是由于金属材料上下表面刻蚀速率差导致的。而在本申请的上述工艺中，对于原本位于沟槽内的金属条块，其侧面上下各处与刻蚀液的接触基本是一致的，因而，侧面上下各处的刻蚀速率差异较小，最终可实现窄线宽、大厚度的金属线结构。
图10至图12公开了上述金属线制作方法的另一个具体实施例。该实施例与图2至图9实施例类似，区别仅在于：采用了不同材质的衬底，并在形成牺牲层前对衬底作了相应处理。
如图10，衬底的材质为COP光学材料。即，衬底为COP衬底7。光学材料COP具有以下特点：高透明，低双折射率，低吸水，高刚性，高耐热，水蒸汽气密性好，符合FDA(美国食品药品监督管理局)标准。
在形成牺牲层2之前，可先在所述COP衬底7上形成灰化阻挡层6。所述灰化阻挡层6的材质可以是氮化硅(SiN)或者氧化硅(SiO)等。所述灰化阻挡层6的厚度可以是100纳米(nm)。所述灰化阻挡层6可采用等离子体增强化学气相沉积(PECVD)工艺沉积。当然，所述灰化阻挡层的材质、厚度和形成工艺不限于此，只要在后续灰化去除牺牲层2的过程中能保护下方的COP衬底7即可。
而后，在灰化阻挡层6上形成牺牲层2，并在所述牺牲层2内形成沟槽。在牺牲层2上沉积金属材料，沉积所形成的金属材料层3既形成在牺牲层2上，也填充在沟槽内，但未填满沟槽。再后，利用光刻胶4填满沟槽，多余的光刻胶4也会形成在沟槽外的金属材料层3。光刻胶4的上表面整体平坦。以氧等离子体(O 2plasma)灰化处理光刻胶4的整个表面。
如图11，通过控制灰化处理的时间，使沟槽外的光刻胶4被完全去除，但沟槽内的金属材料层3上仍保留有光刻胶4(光刻胶图案)。之后，进行湿法刻蚀，以去除沟槽外的金属材料。并去除残留在沟槽内金属材料上方的光 刻胶4。此时仍留在沟槽内的金属材料是后续待进一步刻蚀的金属条块34。
如图12，灰化去除牺牲层2，将金属条块34的侧壁暴露在外。在金属条块34上形成掩模5。并在所述掩模5的保护下，湿法刻蚀所述金属条块34至饱和状态，以形成金属线36。
上述形成牺牲层2及其后续的加工步骤均与图2至图9实施例相同，这里不再详述，参前面的文字即可。
图13至图17公开了上述金属线制作方法的又一个具体实施例。
如图13，提供衬底1，所述衬底1为玻璃，在其它实施例中，衬底也可为其它硬性衬底或柔性衬底。在衬底1上先沉积一层金属种子层8。所述金属种子层8的材质可以是铜，厚度可以是4000埃
Figure PCTCN2021096928-appb-000001
预先形成的金属种子层8，可方便后续的电镀工艺。
在金属种子层8上形成牺牲层2，并在所述牺牲层2内形成沟槽。所述牺牲层2的材质为对光敏感的有机材料，对其光刻(包括曝光、显影等)即可在其内部形成沟槽，所述沟槽在厚度方向上贯穿所述牺牲层，并暴露所述金属种子层。在其它实施例中，牺牲层的材质也可为其它有机材料或无机材料，只要方便在其内部形成沟槽，并在后续过程中可方便去除该牺牲层即可。所形成的沟槽的第一截面形状为上宽下窄的等腰梯形。在其它实施例中，沟槽的第一截面也可为其它形貌，但当其整体呈上宽下窄的形貌时，最终所获得的金属条在形貌稳定性和窄线宽方面都有更佳的性能。在图中实施例中，沟槽顶部的宽度(即最宽处的宽度)约为7微米(μm)，沟槽底部的宽度(即最窄处的宽度)约为4.5微米(μm)，沟槽的厚度(即深度)约为5微米(μm)。当然，本申请不受限于此。
通过电镀的方式在所述沟槽内形成金属材料。由于金属种子层8和牺牲层2的影响，所述金属材料不形成在所述沟槽外。所述金属材料可以是铝(Al)、铜(Cu)或者银(Ag)等高电导率的金属材料。在图中所示实施例中， 所述金属材料是铜，厚度约为2微米(μm)。电镀形成的金属材料是金属条块34，其对应截面形状与沟槽的第一截面形状相同或基本相同。
如图14，可采用氧等离子体(O 2plasma)灰化处理牺牲层2，以将其去除。牺牲层2去除后，金属条块34的侧壁暴露在外。金属条块34上表面的宽度略小于沟槽G上端的宽度，略小于7微米(μm)。所形成的结构如图15所示。
如图16，在金属条块34上形成掩模5。所述掩模5的宽度小于所述金属条块34的宽度，且所述掩模5在所述衬底1上的正投影位于所述金属条块34在所述衬底1上的正投影内，使得在沿该宽度方向上，所述掩模5遮盖所述金属条块34的中间区域的上表面，而暴露所述金属条块34的边缘区域的上表面。具体实施时，掩模5的宽度可被设计为比最终所需金属线的宽度大4微米到6微米，即掩模5在所述宽度方向上的两侧壁均比最终所需金属线的侧壁多向外凸伸2微米到3微米。
所述掩模5是光刻胶曝光、显影后(即，光刻)所形成的光刻胶图案。在其它实施例中，掩模也可以是硬掩膜或其它膜层，只要其在后续的湿法刻蚀工艺中能对金属条块34的上表面起到一定程度的保护作用即可。
在图中实施例中，所述掩模5的第二截面为上窄下宽的等腰梯形。其中，所述第二截面沿掩模5的宽度方向延伸，并垂直于衬底1的上表面。当然，掩模5的第二截面形状不限于此。比如，可以是矩形、非等腰梯形等。但是，掩模5的第二截面采用上窄下宽的形貌时，可更有利于在后续湿法刻蚀工艺中获得更窄线宽的金属条。
而后在所述掩模5的保护下，请参图17，湿法刻蚀所述金属条块34至饱和状态，以形成金属线36，所述金属线36的宽度小于所述掩模5的宽度。最终获得的金属线36的宽度(即线宽)约为1.5微米(μm)。
在上述刻蚀中，随着刻蚀的不断推进，会出现刻蚀饱和的状态。到达 刻蚀饱和状态后，即便再大幅增加刻蚀时间，也无法明显改变对金属条块34的刻蚀结果，无法获得更小的线宽。
在上述刻蚀过程中，刻蚀饱和状态的出现是由于所述掩模5和金属条块34之间的特殊位置关系以及刻蚀液表面张力和扩散造成侧向刻蚀减慢共同作用的结果。并且，上述过程是相对稳定的，即：到达刻蚀饱和状态后，金属线各处的线宽基本保持在生产可用的同一水平内，并且，不同批次所获得的刻蚀结果也是基本稳定的。正式利用此点，上述方法可获得高厚度、窄线宽的金属线36，且所述金属线36的线宽均匀性高。
说明一点，到达饱和状态后，并不意味着继续刻蚀不再能消耗金属条块34的一丝一毫，只是代表继续刻蚀所可收获的刻蚀速度将大大弱于前面稳定刻蚀阶段的刻蚀速度，因而即便继续刻蚀有限的一段时间对金属条块34最终刻蚀结果的影响也极微弱。例如，当刻蚀速度明显小于前面稳定刻蚀阶段的速度或平均速度时，比如小于稳定刻蚀阶段平均速度的三分之一时，即可认为已处于刻蚀饱和状态了。
在上述湿法刻蚀所述金属条块34至饱和状态以形成金属线36的过程中，金属种子层8暴露在外的部分会被同步刻蚀掉。所形成的结构如图17所示。
在其它实施例中，若金属种子层8不能被上述湿法刻蚀工艺同步去除，则可通过单独的步骤去除金属种子层8未紧贴金属线36的区域。具体工艺如图18至图20所示。如图18和图19，可先剥离金属线36上方的掩模5。剥离的方法可以是利用氧等离子体灰化处理。而后，如图20，利用干法刻蚀工艺去除金属线36区域外的金属种子层8。在上述干法刻蚀工艺中，可利用金属线36或另外形成的光刻胶图案作掩模。所采取的刻蚀工艺可以是反应离子刻蚀(RIE)、电感耦合等离子体刻蚀(ICP)和离子束刻蚀(IBE)等。
图21至图24公开了上述金属线制作方法的另一个具体实施例。
如图21，提供衬底1，所述衬底1为玻璃，在其它实施例中，衬底也可为其它硬性衬底或柔性衬底。
在衬底1形成牺牲层2，并在所述牺牲层2内形成第一沟槽T1和第二沟槽T2，所述第一沟槽T1和所述第二沟槽T2相互隔离。所述牺牲层2的材质为对光敏感的有机材料，对其光刻(包括曝光、显影等)即可在其内部同步形成第一沟槽T1和第二沟槽T2，所述第一沟槽T1和第二沟槽T2在厚度方向上贯穿所述牺牲层。在其它实施例中，牺牲层的材质也可为其它有机材料或无机材料，只要方便在其内部形成第一沟槽T1和第二沟槽T2，并在后续过程中可方便去除该牺牲层即可。
所形成的第一沟槽T1和第二沟槽T2的截面形状可以为矩形，第一沟槽T1和第二沟槽T2侧壁的坡度较陡，在80度(包含本数)至90度(包含本数)之间。可利用曝光后欠显影的方式来提高和实现较陡的坡度。也可利用压模压制的方式来形成第一沟槽和第二沟槽，并保证它们的坡度。
具体实施中，第一沟槽T1和第二沟槽T2的宽度在2微米(μm)以上(含2微米)，厚度(深度)在1微米以上(含1微米)时，有利于实现第一沟槽、第二沟槽内沉积的金属与第一沟槽、第二沟槽外的金属不相粘连，进而有利于最终形成的金属线的质量。
如图22，在牺牲层2上沉积金属材料，所沉积的厚度满足设计和生产需求。可利用直流式溅镀或蒸镀的方式来沉积，所沉积的金属可以是铝(Al)、铜(Cu)或者银(Ag)等高电导率的金属材料。在图中所示实施例中，所沉积金属材料是铝，厚度约为2微米(μm)。沉积所形成的金属材料层9既形成在牺牲层2上，也填充在第一沟槽T1和第二沟槽T2内。作为较优的实施方式，金属材料层9最好不填满第一沟槽T1和第二沟槽T2。由于坡度较陡，第一沟槽T1和第二沟槽T2的侧壁上未粘连或几乎不粘连金属材料。位于第一沟槽T1和第二沟槽T2之间的牺牲层2上方的金属材料作为金属条块34，如图22所示，金属条块34与其它区域的金属材料层9不相粘连。
如图23，在金属条块34上形成掩模5。所述掩模5的宽度小于所述金属条块34的宽度，且所述掩模5在所述衬底1上的正投影位于所述金属条块34在所述衬底1上的正投影内，使得在沿该宽度方向上，所述掩模5遮盖所述金属条块34的中间区域的上表面，而暴露所述金属条块34的边缘区域的上表面。具体实施时，掩模5的宽度可被设计为比最终所需金属线的宽度大4微米到6微米，即掩模5在所述宽度方向上的两侧壁均比最终所需金属线的侧壁多向外凸伸2微米到3微米。
所述掩模5是光刻胶曝光、显影后(即，光刻)所形成的光刻胶图案。在其它实施例中，掩模也可以是硬掩膜或其它膜层，只要其在后续的湿法刻蚀工艺中能对金属条块34的上表面起到一定程度的保护作用即可。
在图中实施例中，所述掩模5的第二截面为上窄下宽的等腰梯形。其中，所述第二截面沿掩模5的宽度方向延伸，并垂直于衬底1的上表面。当然，掩模5的第二截面形状不限于此。比如，可以是矩形、非等腰梯形等。但是，掩模5的第二截面采用上窄下宽的形貌时，可更有利于在后续湿法刻蚀工艺中获得更窄线宽的金属条。
如图24，在所述掩模5的保护下，湿法刻蚀所述金属条块34和其它区域的金属材料层9至饱和状态，以形成金属线36，所述金属线36的宽度小于所述掩模5的宽度。最终获得的金属线36的宽度(即线宽)约为1.5微米(μm)。
在上述刻蚀中，随着刻蚀的不断推进，会出现刻蚀饱和的状态。到达刻蚀饱和状态后，即便再大幅增加刻蚀时间，也无法明显改变对金属条块34的刻蚀结果，无法获得更小的线宽。
在上述刻蚀过程中，刻蚀饱和状态的出现是由于所述掩模5和金属条块34之间的特殊位置关系以及刻蚀液表面张力和扩散造成侧向刻蚀减慢共同作用的结果。并且，上述过程是相对稳定的，即：到达刻蚀饱和状态后，金 属线各处的线宽基本保持在生产可用的同一水平内，并且，不同批次所获得的刻蚀结果也是基本稳定的。正式利用此点，上述方法可获得高厚度、窄线宽的金属线36，且所述金属线36的线宽均匀性高。
说明一点，到达饱和状态后，并不意味着继续刻蚀不再能消耗金属条块34的一丝一毫，只是代表继续刻蚀所可收获的刻蚀速度将大大弱于前面稳定刻蚀阶段的刻蚀速度，因而即便继续刻蚀有限的一段时间对金属条块34最终刻蚀结果的影响也极微弱。例如，当刻蚀速度明显小于前面稳定刻蚀阶段的速度或平均速度时，比如小于稳定刻蚀阶段平均速度的三分之一时，即可认为已处于刻蚀饱和状态了。
相关技术对金属材料的刻蚀中，金属材料侧面的刻蚀坡度约为45度，是由于金属材料上下表面刻蚀速率差导致的。而在本申请的上述工艺中，对于在第一沟槽和第二沟槽之间的金属条块，其侧面上下各处与刻蚀液的接触基本是一致的，因而，侧面上下各处的刻蚀速率差异较小，最终可实现窄线宽、大厚度的金属线结构。
图25至图27公开了上述金属线制作方法的又一个具体实施例。该实施例与图21至图24实施例基本相同，区别仅在于两者形成第一沟槽和第二沟槽的方法不同，其它的步骤均完全相同。
如图25，在衬底1上形成整层的牺牲层2后，先在所述牺牲层2上形成硬掩膜10，所述硬掩膜10在对应所述第一沟槽和所述第二沟槽处形成有开口。所述硬掩膜10的材质可以是钼(Mo)、铝(Al)、氧化铟锡(ITO)或者铟镓锌氧化物(IGZO)等。所述硬掩膜10与牺牲层2间具有较大的刻蚀选择比。在图中实施例中，所述硬掩膜10是厚度为1350埃的氧化铟锡膜层。
如图26，利用所述硬掩膜10对所述牺牲层2进行干法刻蚀，以在所述牺牲层2内形成第一沟槽T1和第二沟槽T2。由于两者的刻蚀选择比较大，在上述干法刻蚀中可保证第一沟槽T1和第二沟槽T2具有优良的精度，第一 沟槽T1和第二沟槽T2的侧壁的坡度可以得到较好的实现。
如图27，在沉积金属材料之前，可先去除所述硬掩膜10。随后的步骤工艺(比如，沉积金属材料、在金属条块上形成掩模以及在掩模的保护下湿法刻蚀金属条块至饱和状态)均与图21至图24实施例相同。
虽然上述各实施例中只是示出了一个金属条块，介绍了如何对该金属条块进行加工，以制作出一个高厚度、窄线宽的金属线，但是，本领域技术人员容易理解，上述制作方法同样适用于同步或不同步加工多个独立或不独立的金属条块，进而获得多个独立或不独立的高厚度、窄线宽的金属条。即，对本申请实施例的上述简单变更仍在本申请的保护范围之内。
本申请还提供一种金属线，其可由上述任一制作方法所制得。所述金属线可应用于显示装置、移动终端上的屏上天线、光子芯片、光栅、偏振等上。
需要指出的是，在附图中，为了图示的清晰可能夸大了层和区域的尺寸。而且可以理解，当元件或层被称为在另一元件或层“上”时，它可以直接在其他元件上，或者可以存在中间的层。另外，可以理解，当元件或层被称为在另一元件或层“下”时，它可以直接在其他元件下，或者可以存在一个以上的中间的层或元件。另外，还可以理解，当层或元件被称为在两层或两个元件“之间”时，它可以为两层或两个元件之间唯一的层，或还可以存在一个以上的中间层或元件。通篇相似的参考标记指示相似的元件。
本领域技术人员在考虑说明书及实践这里公开的公开后，将容易想到本申请的其它实施方案。本申请旨在涵盖本申请的任何变型、用途或者适应性变化，这些变型、用途或者适应性变化遵循本申请的一般性原理并包括本申请未公开的本技术领域中的公知常识或惯用技术手段。说明书和实施例仅被视为示例性的，本申请的真正范围和精神由下面的权利要求指出。
应当理解的是，本申请并不局限于上面已经描述并在附图中示出的精 确结构，并且可以在不脱离其范围进行各种修改和改变。本申请的范围仅由所附的权利要求来限制。

Claims (19)

  1. 一种金属线的制作方法，其特征在于，所述制作方法包括：
    在衬底上形成金属条块；
    在所述金属条块的上方形成掩模，所述掩模的宽度小于所述金属条块的宽度，且所述掩模在所述衬底上的正投影位于所述金属条块在所述衬底上的正投影内；
    在所述掩模的保护下，湿法刻蚀所述金属条块至饱和状态，以形成金属线，所述金属线的宽度小于所述掩模的宽度。
  2. 根据权利要求1所述的制作方法，其特征在于，在衬底上形成金属条块，包括：
    在衬底上形成牺牲层，所述牺牲层内形成有沟槽；
    在所述沟槽内填充金属材料；
    去除所述牺牲层。
  3. 根据权利要求2所述的制作方法，其特征在于，所述牺牲层的材质为对光敏感的有机材料，通过对所述牺牲层进行光刻形成所述沟槽，通过灰化的方式去除所述牺牲层。
  4. 根据权利要求2所述的制作方法，其特征在于，所述沟槽在沿所述宽度方向上具有垂直于所述衬底的第一截面，所述第一截面整体呈上宽下窄的形貌。
  5. 根据权利要求4所述的制作方法，其特征在于，所述沟槽的所述第一截面为等腰梯形。
  6. 根据权利要求2所述的制作方法，其特征在于，在所述沟槽内填充金属材料，包括：
    在所述牺牲层上和所述沟槽内沉积金属材料；
    形成光刻胶图案，所述光刻胶图案遮盖所述沟槽内的金属材料，而暴露所述沟槽外的金属材料；
    在所述光刻胶图案的保护下刻蚀金属材料，以去除所述沟槽外的金属材料。
  7. 根据权利要求1所述的制作方法，其特征在于，所述掩模在沿所述宽度方向上具有垂直于所述衬底的第二截面，所述第二截面整体呈上窄下宽的形貌。
  8. 根据权利要求7所述的制作方法，其特征在于，所述掩模的所述第二截面为等腰梯形。
  9. 根据权利要求2所述的制作方法，其特征在于，所述衬底包括COP光学材料；
    在衬底上形成牺牲层之前，先在所述衬底上形成灰化阻挡层，所述牺牲层形成在所述灰化阻挡层上。
  10. 根据权利要求9所述的制作方法，其特征在于，所述灰化阻挡层的材质包括氮化硅或者氧化硅。
  11. 根据权利要求2所述的制作方法，其特征在于，在衬底上形成牺牲层之前，先在所述衬底上形成金属种子层，所述牺牲层形成在所述金属种子层，在所述牺牲层内形成的所述沟槽暴露所述金属种子层；
    通过电镀的方式在所述沟槽内填充金属材料，且所述金属材料不形成在所述沟槽外。
  12. 根据权利要求11所述的制作方法，其特征在于，在湿法刻蚀所述金属条块以形成金属线的过程中，所述金属种子层外露的部分被同步去除或未被同步去除。
  13. 根据权利要求1所述的制作方法，其特征在于，在衬底上形成金属条块，包括：
    在衬底上形成牺牲层；
    在所述牺牲层内形成第一沟槽和第二沟槽，所述第一沟槽和所述第二沟槽相互隔离，并沿所述宽度方向排列；
    沉积金属材料，其中形成在所述第一沟槽和所述第二沟槽之间的所述牺 牲层上方的金属材料作为所述金属条块。
  14. 根据权利要求13所述的制作方法，其特征在于，所述牺牲层的材质为对光敏感的有机材料，通过对所述牺牲层进行光刻形成所述第一沟槽和所述第二沟槽。
  15. 根据权利要求13所述的制作方法，其特征在于，所述第一沟槽和/或所述第二沟槽的宽度大于或等于2微米，所述第一沟槽和/或所述第二沟槽的侧壁的坡度大于或等于80度并且小于或等于90度。
  16. 根据权利要求13所述的制作方法，其特征在于，在形成第一沟槽和第二沟槽之前，先在所述牺牲层上形成硬掩膜，所述硬掩膜在对应所述第一沟槽和所述第二沟槽处形成有开口；
    利用所述硬掩膜对所述牺牲层进行干法刻蚀，以在所述牺牲层内形成第一沟槽和第二沟槽。
  17. 根据权利要求16所述的制作方法，其特征在于，在沉积金属材料之前，去除所述硬掩膜。
  18. 根据权利要求16所述的制作方法，其特征在于，所述硬掩膜的材质包括钼、铝、氧化铟锡或者铟镓锌氧化物。
  19. 一种根据权利要求1-18任一项所述制作方法所制得的金属线。
PCT/CN2021/096928 2021-05-28 2021-05-28 金属线及其制作方法 WO2022246836A1 (zh)

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US17/775,714 US20240153782A1 (en) 2021-05-28 2021-05-28 Metal wires and methods for manufacturing the same

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1405856A (zh) * 2001-09-19 2003-03-26 联华电子股份有限公司 蚀刻多晶硅层以形成多晶硅闸极的方法
CN1992150A (zh) * 2005-12-30 2007-07-04 中华映管股份有限公司 薄膜刻蚀方法
JP2008130923A (ja) * 2006-11-22 2008-06-05 Seiko Epson Corp 半導体装置の製造方法
US20130059435A1 (en) * 2011-09-01 2013-03-07 Tao Yang Method of Manufacturing Dummy Gates in Gate Last Process
CN103034049A (zh) * 2012-12-13 2013-04-10 京东方科技集团股份有限公司 金属线及阵列基板的制作方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1405856A (zh) * 2001-09-19 2003-03-26 联华电子股份有限公司 蚀刻多晶硅层以形成多晶硅闸极的方法
CN1992150A (zh) * 2005-12-30 2007-07-04 中华映管股份有限公司 薄膜刻蚀方法
JP2008130923A (ja) * 2006-11-22 2008-06-05 Seiko Epson Corp 半導体装置の製造方法
US20130059435A1 (en) * 2011-09-01 2013-03-07 Tao Yang Method of Manufacturing Dummy Gates in Gate Last Process
CN103034049A (zh) * 2012-12-13 2013-04-10 京东方科技集团股份有限公司 金属线及阵列基板的制作方法

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