CN113302730A - Processing system and platform for reducing material roughness using irradiated etching solution - Google Patents

Processing system and platform for reducing material roughness using irradiated etching solution Download PDF

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CN113302730A
CN113302730A CN201980089026.9A CN201980089026A CN113302730A CN 113302730 A CN113302730 A CN 113302730A CN 201980089026 A CN201980089026 A CN 201980089026A CN 113302730 A CN113302730 A CN 113302730A
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etching solution
processing system
etch
substrate
liquid
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奥米德·赞迪
雅克·法戈特
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Tokyo Electron Ltd
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Tokyo Electron Ltd
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Priority claimed from US16/287,669 external-priority patent/US10896824B2/en
Priority claimed from US16/402,634 external-priority patent/US20200075351A1/en
Application filed by Tokyo Electron Ltd filed Critical Tokyo Electron Ltd
Publication of CN113302730A publication Critical patent/CN113302730A/en
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    • H—ELECTRICITY
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    • 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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67063—Apparatus for fluid treatment for etching
    • H01L21/67075—Apparatus for fluid treatment for etching for wet etching
    • H—ELECTRICITY
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    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
    • H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
    • H01L21/32134—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by liquid etching only
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    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26—Bombardment with radiation
    • H01L21/263—Bombardment with radiation with high-energy radiation
    • H01L21/2633—Bombardment with radiation with high-energy radiation for etching, e.g. sputteretching
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    • 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
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
    • H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
    • H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
    • H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
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    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02296—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer
    • H01L21/02299—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer pre-treatment
    • H01L21/02307—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer pre-treatment treatment by exposure to a liquid
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    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02296—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer
    • H01L21/02299—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer pre-treatment
    • H01L21/0231—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer pre-treatment treatment by exposure to electromagnetic radiation, e.g. UV light
    • H—ELECTRICITY
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    • 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
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
    • H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
    • H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
    • H01L21/0274—Photolithographic processes
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    • 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
    • H01L21/30604—Chemical etching
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    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67063—Apparatus for fluid treatment for etching
    • H—ELECTRICITY
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    • 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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67063—Apparatus for fluid treatment for etching
    • H01L21/67075—Apparatus for fluid treatment for etching for wet etching
    • H01L21/6708—Apparatus for fluid treatment for etching for wet etching using mainly spraying means, e.g. nozzles

Abstract

Embodiments of a processing system and platform are described that irradiate an etching solution to provide controlled etching of a material. These processing systems and platforms deposit a liquid etching solution on the material to be etched and irradiate the liquid etching solution to adjust the reactant levels. The liquid etching solution has a first reactant level and the irradiating causes the liquid etching solution to have a second reactant level different from the first level. The material is modified with the irradiated etching solution, and the modified material is removed. The delivering, exposing, and removing can be repeated to provide a cyclical etch. Further, oxidation and dissolution may occur simultaneously or may occur in multiple steps. The material being etched may be polycrystalline material, polycrystalline metal, and/or other materials. The liquid etching solution may include hydrogen peroxide that is irradiated to form perhydroxyl radicals.

Description

Processing system and platform for reducing material roughness using irradiated etching solution
Cross Reference to Related Applications
The present application also claims priority from: U.S. provisional patent application serial No. 62/779,604 entitled "roughnessreduction METHODS FOR WET etching OF POLYCRYSTALLINE MATERIALS" filed 12, 14.2018; and us provisional patent application serial No. 62/726,603 entitled "photomodulation etchant reactivity" filed on 4.11.2018; and U.S. patent application serial No. 16/287,669 entitled "rolling REDUCTION METHODS FOR MATERIALS USING an irradiated etching solution" filed on 27.2.2019; U.S. patent application Ser. No. 16/402,634, filed on 3.5.2019, each OF which is incorporated herein by reference in its entirety, entitled "PROCESSING SYSTEMS AND PLATFORMS FOR ROUGHNESS REDUCTION OF MATERIALS USE ILLUMINATED ETCH SOLUTIONS" USING a radiation etching solution.
Background
The present disclosure relates to methods for the fabrication of microelectronic workpieces, including etching processes for material layers on microelectronic workpieces.
Device formation within a microelectronic workpiece typically involves a series of manufacturing techniques related to the formation, patterning, and removal of multiple material layers on a substrate of the microelectronic workpiece. An etching process is typically used to remove a layer of material from the surface of a substrate. As the feature sizes of materials to be etched for electronic devices formed on microelectronic workpieces continue to shrink, it becomes increasingly difficult to control etch uniformity on a macro-scale and a micro-scale. Conventional wet etch processes using liquid etch solutions typically lack precise nanoscale control over etch behavior. This lack of control becomes problematic where there is a small amount of material to be removed and/or where a smooth surface finish is desired.
In particular, roughness control during an etching process for polycrystalline materials is a challenging task. Polycrystalline materials exhibit varying reactivity to etchants depending on the surface crystal orientation of the polycrystalline material. Polycrystalline materials also exhibit varying reactivity to etchants at grain boundaries and defect sites of the polycrystalline material. This varying reactivity leads to undesirable etch variability and surface roughness in conventional wet etch processes.
Fig. 1A-1B (prior art) provide simplified diagrams associated with such prior etching solutions and associated problems with varying reactivity and undesirable etch variability.
Turning first to fig. 1A (prior art), an exemplary embodiment 100 for a conventional etching method is provided. A liquid etching solution 106 is applied to the material 104 on the surface of the substrate 108 of the microelectronic workpiece. For the example embodiment 100, the material 104 being etched is cobalt (Co), and this material 104 has been previously formed on the surface of the substrate 108. For the example embodiment 100, the liquid etching solution 106 provides an oxidative dissolution etching mechanism. For this oxidative dissolution etch mechanism, the material 104 is oxidized by the liquid etch solution 106 and then dissolved by the liquid etch solution 106.
The conventional oxidative dissolution etch mechanism for cobalt results in significant roughening and pitting. With this conventional approach, cobalt etching is driven by an oxidation/dissolution mechanism, in which an oxidant (e.g., hydrogen peroxide) oxidizes cobalt (Co) to form CoOxThe oxidation rate of which is alwaysNumber kox(as represented by arrow 110). Then CoOxDissolved in solution by complexation with etchant molecules (e.g., citrate anions) with a dissolution rate constant kd(as represented by arrow 112). For this conventional approach, koxLess than kd(kox<kd) And this condition causes uneven etching at grain boundaries of the polycrystalline cobalt, resulting in pitting and roughening of the surface.
Fig. 1B (prior art) provides a representative surface image 150 for such pitting and roughening of the surface due to the undesirable etch variability associated with conventional oxidative dissolution methods. In contrast, an ideal wet etch process will provide a constant etch rate independent of the surface chemistry (e.g., grain boundaries) of the material being etched.
Disclosure of Invention
Embodiments are described herein that use irradiation of an etching solution to provide controlled etching of a material. The disclosed processing system and platform deposit liquid etching solutions on the material to be etched and irradiate the liquid etching solutions to adjust the reactant levels. The material being etched may be, for example, polycrystalline material, polycrystalline metal, and/or other material to be etched. The disclosed embodiments use irradiation as a tool to control the etchant reactivity in the etching solution in contact with the material to achieve modification of the etching behavior. Chemical compositions and other parameters may also be used to control, in part, etch behavior and post-etch surface morphology and chemistry. The disclosed embodiments thereby control and/or reduce surface roughness during etching of materials (such as polycrystalline materials) on a microscopic level and a macroscopic level. These results are achieved by: the etching solution applied to the surface of the material is irradiated to generate highly reactive etchants at the point of use that etch the material independent of the surface chemistry of the material. For one example embodiment, the liquid etching solution is an aqueous solution containing hydrogen peroxide, and hydroxyl radicals are generated by irradiation (such as ultraviolet light), thereby forming a highly reactive etchant. Different or additional features, variations and embodiments may also be implemented, and related systems and methods may also be utilized.
For one embodiment, a processing system for performing a wet etch process on a substrate is disclosed, the processing system comprising: a wet process chamber configured to perform a wet etching process; a substrate holder located within the wet process chamber, the substrate holder configured to support a substrate; a delivery system arranged to supply a liquid etching solution to the substrate, the liquid etching solution having a first reactant level with respect to a material on a surface of the substrate; an illumination system arranged to illuminate the liquid etching solution to cause the etching solution to have a second reactant level for the material different from the first level; and a controller coupled to the delivery system to control delivery of the liquid etching solution and coupled to the illumination system to control illumination output by the illumination system.
In additional embodiments, the controller is configured to control the illumination system and the delivery system to etch the material in a cyclical manner.
In additional embodiments, the liquid etching solution, when irradiated, oxidizes the surface of the material to form an oxidized material as a modified layer. In a further embodiment, a uniform layer of oxide material is formed as the modified layer, and the liquid etching solution further dissolves the oxide material. In still further embodiments, the liquid etching solution comprises an aqueous solution comprising hydrogen peroxide and citrate. In a further embodiment, the delivery system is further configured to deliver an aqueous solution comprising a complexing agent to dissolve the oxidizing material. In still further embodiments, the complexing agent comprises at least one of citrate, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), malic acid, oxalic acid, glycine, alanine, or iminodiacetic acid.
In additional embodiments, the material to be etched comprises a polycrystalline material. In a further embodiment, the polycrystalline material comprises at least one of polycrystalline metal, polycrystalline cobalt, ruthenium, tungsten, titanium, tantalum, titanium nitride, or tantalum nitride.
In additional embodiments, the illumination system is configured to selectively illuminate the liquid etching solution. In a further embodiment, the illumination system is configured to selectively illuminate the liquid etching solution with Ultraviolet (UV) light in one or more on/off modes. In a further embodiment, the illumination system is configured to selectively illuminate with two or more different colors of light.
In additional embodiments, the controller is configured to control the illumination system to cause different exposures to different regions of the liquid etching solution to provide different amounts of etching to the material within the different regions. In a further embodiment, the different exposures are based on measurements of at least one of a topology of a surface of the material or a thickness of the material.
For one embodiment, a platform for etching a substrate is disclosed, the platform comprising: a dry etch processing system for etching the polycrystalline material on the substrate using dry etch chemistry; a wet etch processing system for etching the polycrystalline material to mitigate roughness of the polycrystalline material caused by the dry etch chemistry; a transfer module coupled to move the substrate between the dry etch processing system and the wet etch processing system; and an isolation pass-through module coupled between the transfer module and the wet etch processing tool, wherein the isolation pass-through module separates an ambient environment of the transfer module from an ambient environment of the wet etch processing system. For the platen, the wet etch processing system comprises: a wet process chamber configured to perform a wet etching process; a substrate holder located within the wet process chamber, the substrate holder configured to support a substrate; a delivery system arranged to supply a liquid etching solution to the substrate, the liquid etching solution having a first reactant level with respect to the polycrystalline material; an illumination system arranged to illuminate the liquid etching solution to cause the etching solution to have a second reactant level for the polycrystalline material different from the first level; and a controller coupled to the delivery system to control delivery of the liquid etching solution and coupled to the illumination system to control illumination output by the illumination system.
In additional embodiments, the controller is configured to control the illumination system and the transport system to etch the polycrystalline material in a cyclical manner.
In additional embodiments, the liquid etching solution, when irradiated, oxidizes the surface of the polycrystalline material to form an oxidized material as a modified layer. In further additional embodiments, the liquid etching solution comprises an aqueous solution comprising hydrogen peroxide, and the irradiation comprises Ultraviolet (UV) light.
In additional embodiments, the dry etch processing system implements one or more dry etch processes. In a further embodiment, the one or more dry etch processes include at least one of a plasma etch process, a Reactive Ion Etch (RIE) process, a Chemical Vapor Etch (CVE) process, or an Atomic Layer Etch (ALE) process.
In additional embodiments, the dry etch processing system is configured to etch the polycrystalline material to produce a first surface roughness, and the wet etch process chamber is configured to adjust the first surface roughness to a second surface roughness less than the first surface roughness. In a further embodiment, the controller is configured to control the illumination system to cause different exposures to different regions of the liquid etching solution based on measurements of at least one of a topology of a surface of the material or a thickness of the material to provide different amounts of etching for the polycrystalline material.
Different or additional features, variations and embodiments may also be implemented, and related systems and methods may also be utilized.
Drawings
A more complete understanding of the present invention and the advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments of the disclosed concept and are therefore not to be considered limiting of its scope, for the disclosed concept may admit to other equally effective embodiments.
Fig. 1A (prior art) provides a simplified diagram associated with existing etching solutions that have problems associated with varying reactivity and undesirable etch variability.
Fig. 1B (prior art) provides a representative surface image for pitting and roughness of the surface due to the undesirable etch variability associated with the conventional oxidative dissolution method of fig. 1A (prior art).
Fig. 2A provides an example embodiment in which irradiation of a liquid etching solution is used to facilitate controlling, and preferably real-time controlling, the etch rate and uniformity of etching of a material on a surface of a substrate of a microelectronic workpiece.
Fig. 2B provides a representative surface image of a smooth surface achieved due to the improved etch uniformity associated with the illumination method of fig. 2A.
Fig. 3A provides a representative surface image of roughness prior to a cyclic process mode in which oxidation and dissolution reactions are separated.
Fig. 3B provides a representative surface image of the roughness reduction compared to fig. 3A after etching using the cyclical process mode.
Fig. 3C provides a representative sketch of AFM (atomic force microscopy) surface roughness curves represented by the surface images in fig. 3A and 3B before and after the etching process.
Fig. 4A provides an example embodiment 400 of a scanner solution in which a Light Emitting Diode (LED) is used to irradiate a liquid etching solution applied to a surface of a substrate of a microelectronic workpiece.
Fig. 4B provides an example embodiment of delivering illumination of a liquid etching solution dispensed on a surface of a substrate of a microelectronic workpiece by one or more laser sources.
Figure 5A is a process flow diagram of an example embodiment of using irradiation to adjust reactants within a liquid etching solution to improve etch uniformity for etching material on a surface of a substrate of a microelectronic workpiece.
FIG. 5B is a process flow diagram of an example embodiment of using irradiation to form hydroxyl radicals within a liquid etching solution with hydrogen peroxide to improve etch uniformity for etching polycrystalline metal on a surface of a substrate of a microelectronic workpiece.
Fig. 6 is a process flow diagram of an example embodiment of using irradiation to adjust a reactant within an etching solution (e.g., at least one of a gaseous etching solution, a liquid etching solution, or a combination thereof) to improve etch uniformity for etching material on a surface of a substrate of a microelectronic workpiece.
FIG. 7 is a process flow diagram of an example embodiment for polishing a material using irradiation of an etching solution (e.g., at least one of a gaseous etching solution, a liquid etching solution, or a combination thereof).
FIG. 8A is a block diagram of one example embodiment of a wet etch processing system including a delivery system for a liquid etch solution and an illumination system that may be used in conjunction with the disclosed techniques.
FIG. 8B is a block diagram of an example embodiment for a processing platform that includes a wet etch processing system and a dry etch processing system that may be used in conjunction with the disclosed techniques.
Detailed Description
As described herein, various methods and related processing systems and platforms are disclosed to provide controlled etching of a material (such as a polycrystalline material or a metal) using radiation to adjust etchant reactivity and facilitate etching independent of the surface chemistry of the material. Other advantages and embodiments may also be realized while still utilizing the process techniques described herein.
Controlling the nanoscale etch uniformity helps to minimize device failure of microelectronic devices and circuits formed on the microelectronic workpiece. In general, conventional wet etch chemistries do not provide precise etch control for materials such as poly-crystalline materials and metals. For example, varying etch rates at grain boundaries and/or different crystal facets of a polycrystalline material may cause surface roughening during etching. The disclosed embodiments provide a method for achieving etch uniformity on a micro-scale and a macro-scale by generating a highly reactive etchant at the point of use by controlled irradiation. For one embodiment, the disclosed embodiments provide these beneficial results when used to etch metal poly structures (such as poly-metallic cobalt). Other polycrystalline materials and polycrystalline metals, as well as other materials, may also be etched using the illumination techniques described herein.
For one embodiment, highly reactive hydroxyl radicals (HO) are generated as an etchant for the polycrystalline material by irradiating a liquid etching solution applied to a surface of the polycrystalline material. Hydroxyl radicals are strong oxidizers and etch polycrystalline materials at room temperature. For one embodiment, the hydroxyl radical is hydrogen peroxide (H) in contact with the material to be etched2O2) Ultraviolet (UV) light irradiation of the aqueous solution. The illumination may also be provided selectively at the point of use to better control the etch process and rate.
With this point-of-use solution, one or more areas of a liquid etching solution (e.g., aqueous hydrogen peroxide solution) are selectively irradiated where etching of the surface is desired, while other areas not desired to be etched are not irradiated. For example, irradiation of hydrogen peroxide causes the formation of hydroxyl radicals which cause an increase in the level of reactants. However, once the irradiation is removed, the hydroxyl radicals have a short lifetime and are quickly absorbed back into the aqueous solution. For example, the lifetime of hydroxyl radicals after radiation removal is less than 2 to 5 microseconds. Thus, selective UV irradiation can be used to adjust etchant reactivity to modify the thermodynamics and kinetics of the etching reaction in selected regions of the liquid etching solution. The high reactivity combined with the microsecond lifetime of the hydroxyl radicals enables rapid and/or near instantaneous oxidation of the surface layer of the material independent of local surface reactivity. The oxide layer is then removed, presenting a smooth etched surface. Additionally, large-scale etch uniformity can be achieved by spatially adjusting the UV light intensity in a feed-forward process during the illumination process. Other variations may also be implemented while still utilizing the techniques described herein.
One significant advantage of the disclosed embodiments is the ability to adjust near instantaneous etchant reactivity in situ using controlled irradiation. This tuning capability allows a broader parameter space to be obtained on the potential-pH diagram (i.e., the bubby diagram) of the photosensitive etchant without the need to mix additional reactants and chemicals. This simplifies the process chemistry and reduces the cost of the wet etch process.
As described herein, the disclosed embodiments provide one or more of the following: (1) adjusting the etchant reactivity in real time and at the point of use, thereby adjusting the etching behavior without the need for additional chemical mixtures or aggressive conditions; (2) the short lifetime of reactive transient excited states is exploited by generating them at the surface of a microelectronic workpiece (e.g., a semiconductor wafer) and then using them to etch the surface; (3) controlling surface roughness during etching of the polycrystalline material; (4) time and space control of the etch rate on the surface of the microelectronic workpiece is achieved; and/or (5) provide feed forward control to compensate for non-uniform layer thicknesses across the microelectronic workpiece. Additional and/or different advantages and features may also be provided in accordance with the techniques described herein.
Fig. 2A-2B and 3A-3C provide simplified diagrams associated with the disclosed embodiments in which irradiation is used to adjust the etch rate of a liquid etching solution applied to the surface of a microelectronic workpiece to be etched of polycrystalline material. Additional and/or different embodiments may also be implemented while utilizing the techniques described herein.
It should be noted that the illumination described herein may be selective illumination applied in real time to provide point-of-use control. Liquid etching solutions typically have a set reactivity and etch rate for a given material based on the composition and temperature of the solution. The disclosed embodiments adjust in real time the etching behavior of a liquid etching solution having a given composition at a given temperature. In addition, the disclosed embodiments allow for adjustment of the etch rate with respect to the location and/or positioning of materials on the surface of the microelectronic workpiece, and can utilize feed forward control to achieve better uniformity across the microelectronic workpiece.
It is further noted that conventional etching solutions have a set solution potential and a set pH. The set solution potential and the set pH of the solution places the solution at a single point on the bubye diagram. The parameters are set by the solution composition. The solution composition uniquely sets the type of thermodynamic equilibrium that will occur when the solution is brought into contact with the surface to be etched, and also sets the solubility of the etch products. Thus, the etching behavior of the system is determined.
In contrast, the disclosed embodiments provide a wet etch process that uses irradiation to adjust etchant reactivity and/or the potential of the etching solution and thus achieve the desired etch behavior. For the embodiments herein, the etching solution contains a photosensitive compound that undergoes a photochemical reaction upon irradiation to generate a reactive etchant (e.g., a radical or radical ion). The liquid etching solution may also contain additional components for dissolving or volatilizing the etch products.
For one embodiment, hydroxyl radicals (HO) are used as transient excited species and are generated by photolysis of hydrogen peroxide. Other examples include, but are not limited to, singlet oxygen, excited molecules, radicals, dimers, complexes, and/or other materials having properties that generate and/or modulate a reactive etchant upon irradiation. For example, similar reactive species may be generated by photolysis of ozone or aqueous hypochlorous acid solutions. Other variations may also be implemented.
For one example embodiment, the disclosed embodiments are used to reduce roughening in etching of polycrystalline metal materials. In a further example embodiment, the polycrystalline metal material is cobalt.
Wet etching of polycrystalline materials is typically accomplished by an oxidative dissolution mechanism. The etchant solution contains an oxidizing agent and a reactant that promote dissolution of the etch products. The etching behavior (e.g., etch rate, etch uniformity) and thus the final surface morphology depends on the chemical reactions that occur on the surface of the material to be etched. Varying etch rates on polycrystalline materials are a common problem with conventional wet etch processes, where such variability often leads to undesirable surface morphology such as roughening and pitting. As described herein, the adjustment of the oxidation reaction rate and dissolution reaction rate by irradiation (preferably in real time) allows for modification of the etch behavior and for uniform etching.
Hydrogen peroxide is a commonly used etchant in wet etch processes. As recognized in the current embodiment, irradiation of hydrogen peroxide with light having a wavelength (λ) less than 560 nanometers (nm) (i.e., λ <560nm) results in quantitative photolysis of the formation of hydroxyl radicals. For example, UV light having a wavelength of 10nm to 400nm (e.g., 10nm ≦ λ ≦ 400nm) may be used for such irradiation. Hydroxyl radicals possess very high oxidation potentials (e.g., 2.8 volts) and have microsecond lifetimes (e.g., lifetimes ≦ 2 to 5 microseconds). The combination of high reactivity and short lifetime allows the uniform surface layer to be oxidized nearly instantaneously and then the oxidized surface layer can be removed.
Cobalt may be considered as an example polycrystalline material that may be etched using the disclosed embodiments.
Turning first to fig. 2A, an example embodiment 200 is provided in accordance with the disclosed technique in which irradiation of a liquid etching solution is used to facilitate control, and preferably real-time control, of etch rate and uniformity, as described herein. A liquid etching solution 206 is applied to the material 204 on the surface of a substrate 208 of the microelectronic workpiece. For the example embodiment 200, the material 204 being etched is cobalt (Co), and this material 204 has been previously formed on the surface of the substrate 208. For the example embodiment 200, the liquid etching solution 206 provides an oxidative dissolution etching mechanism. For this oxidative dissolution etch mechanism, the material 204 is oxidized by the liquid etch solution 206 and then dissolved by the liquid etch solution 206. In contrast to prior solutions and in accordance with the techniques described herein, the illumination 205 is used to transition the liquid etching solution 206 from a first reactant level with respect to the material 204 on the surface of the substrate 208 to a second reactant level with respect to the material 204. Further, the second reactant level is greater than the first reactant level.
For one embodiment, a composition comprising hydrogen peroxide (H) is used2O2) The liquid etching solution of (1). When irradiated with UV light, hydrogen peroxide cleaves to form two hydroxyl radicals (OH). This formation of hydroxyl radicals increases the oxidation potential of the solution from about 1.8 volts (V) to about 2.8V. The reactive hydroxyl radical accelerates the oxidation reaction and leads to an oxidation rate constant kox(as represented by arrow 210) is much greater than the dissolution rate constant kd(as represented by arrow 212). This significantly increased oxidation rate (k) relative to the dissolution rateox>>kd) Promoting the formation of a thin and uniform layer of oxide material 214 at a constant rate over the surface of the material. The oxide material 214 is then slowly removed, thereby presenting a smooth surface. In the case of cobalt as material 108, cobalt oxide (CoO)x) Is an oxide material 214.
Fig. 2B provides a representative surface image 250 of such a smooth surface achieved due to the improved etch uniformity associated with the illumination methods of the disclosed embodiments described herein. For the representative surface image 250, the scale is provided by bars 252 representing a length of 500 nm.
It should be noted that the rapid formation of the surface oxide layer additionally prevents the diffusion of the etchant through grain boundaries and defect sites of the polycrystalline material, thereby reducing or minimizing pitting. Corrosion associated with pitting does not occur or is reduced using the illumination techniques described herein, based on surface morphology analysis. In addition, the surface roughness is significantly reduced from the initial value. Additional and/or different advantages may also be realized.
Example process modes were also tested using the UV enhanced peroxide (UVP) wet etch method described herein with respect to etching of polycrystalline materials. For these example process modes, two example process modes applying the UVP wet etch method were used to etch the polycrystalline cobalt: a continuous UVP process and a cyclic oxidative dissolution process.
For the continuous UVP process example, hydrogen peroxide (H) adjusted to pH 10(pH 10) was used2O2) And citric acid (e.g., in the form of citrate salt). The oxidation reaction and the dissolution reaction in this mode are carried out simultaneously. The results of this process using illumination are shown in fig. 2B with respect to representative image 250. The results of this process without the use of illumination are shown in fig. 1B (prior art) with respect to a representative surface image 150.
As described above, fig. 1A (prior art) provides cobalt with hydrogen peroxide (H) in the absence of UV irradiation2O2) Example 100 of oxidation and dissolution reaction rates in contact with aqueous citrate solutions. Fig. 1B (prior art) corresponds to an example surface image 150 of the post-etch morphology for the process represented by fig. 1A (prior art) without UV illumination.
In contrast to that described above, FIG. 2A provides that cobalt and H are present in the presence of UV radiation2O2Example 200 of oxidation and dissolution reaction rates in contact with aqueous citrate solutions. Fig. 2B corresponds to an example surface image 250 of the post-etch morphology for the process with UV illumination represented by fig. 2A. UV irradiation generates transient hydroxyl radicals to achieve a higher oxidation rate, which causes a reduction in surface roughness even with a very low amount of etching.
For one embodiment, a cyclic process mode is used. For this example of a cyclic process mode, the oxidation reaction and the dissolution reaction are separated. In the first step, cobalt is oxidized with an irradiation process (e.g., UVP process) for a given time without citrate (e.g., dissolution removal). The layer of oxidizing material (e.g., cobalt oxide) is then removed using an aqueous solution of citric acid (e.g., in the form of a citrate salt). Careful control of the UVP oxidation time and dissolution time allows the cobalt to be etched uniformly.
It should be noted that the complexing agent is not limited to citrate, but that different complexing agents may also be used for this purpose. For example, the complexing agent may include ligands from the families of carboxylic acids, amines, amino acids, alcohols, and the like. Examples include, but are not limited to: ethylenediamine, ethylenediaminetetraacetic acid (EDTA), malic acid, oxalic acid, glycine, alanine, and iminodiacetic acid. It should further be noted that the removal rate depends on the type of complexing agent.
Representative results of this cyclical process mode are provided in fig. 3A-3C.
Fig. 3A provides a representative surface image 300 of the roughness prior to the cyclical process. The diagram shows the material on the surface of the substrate as received. For this example, the thickness of the material layer is 30nm and the RMS (root mean square) roughness is 1.76 nm.
Fig. 3B provides a representative surface image 350 of reduced roughness compared to fig. 3A after etching of polycrystalline cobalt using a cyclical UVP process. The etch has removed 4nm and the material layer is now 26nm thick. The RMS roughness improved to 0.86nm and a reduction in roughness was seen in the surface image. For the representative surface image 350, the scale is provided by bars 352 representing a 200nm length.
Fig. 3C provides a representative sketch 370 of an AFM (atomic force microscopy) surface roughness curve 374/376 represented by the surface images in fig. 3A and 3B before and after the etching process. Roughness curve 374/376 shows the smoothness effect of the etching process, for example, after etching 4nm from the surface of polycrystalline cobalt. The vertical axis represents the normalized height of the surface in nanometers, and the horizontal axis represents the length in one direction along the surface of the material in micrometers (μm). The top line is a roughness curve 374 representing the surface of the material as received, and the surface variation as received is represented by bar 378. The bottom line is a roughness curve 376 representing the surface of the material after 4nm etching and the surface variation after etching is represented by the bars 380. For the representative diagram 370 and roughness curve 374/376, the scale is provided by bars 372 representing a length of 4 nm. As can be seen, this cyclic process significantly reduces the surface roughness.
For additional embodiments, the etch rate over a relatively large surface area of the substrate of the microelectronic workpiece may be controlled by spatial and/or temporal control of the intensity of the UV light delivered to the liquid etching solution. For example, for spatial control, different areas of the liquid etching solution may be irradiated with UV light while other areas of the liquid etching solution are kept unexposed to UV light. For time control, UV light may be applied to different areas of the surface for different amounts of time. Thus, by adjusting the spatial and/or temporal illumination of the surface of the microelectronic workpiece, different etch rates are achieved.
Various illumination systems may be used to illuminate a liquid etching solution applied to a surface of a substrate of a microelectronic workpiece, including rotator solutions and laser/scanner solutions. When implemented on a rotator, the illumination source may optionally be synchronized with the motion of the substrate, thereby enabling illumination of various areas of the wafer with time-invariant intensity. For example, spatially resolved illumination may be achieved with an array of Light Emitting Diodes (LEDs). LED arrays work well when low spatial resolution is acceptable. The LED array may be rotated in the spin chamber in synchronism with the substrate, or the spatial intensity of the array may be synchronized with the motion of the wafer. When higher spatial resolution is desired, a laser source and scanner may be used to provide illumination. The laser source may be moved/scanned across the wafer surface in such a motion: providing higher light intensity for areas of the wafer where higher etch rates are desired. Both of these example embodiments may be used to illuminate a wafer at a single wavelength or multiple wavelengths to condition the reactants in the wet etch solution. It should be noted that other light sources may be used. Further, a light source may be combined, for example, a full-scale exposure of the region enhanced by precise laser scanning may be used as the illumination system. Other variations and embodiments may also be used while still utilizing the techniques described herein.
Fig. 4A-4B provide example embodiments of a scanner solution and a laser/scanner solution for illumination of a surface of a microelectronic workpiece.
Turning first to fig. 4A, an example embodiment 400 for a scanner solution is provided in which an LED array 402 is used to irradiate a liquid etching solution applied to a surface of a substrate of a microelectronic workpiece, such as a semiconductor wafer 404. Prior to irradiation, a liquid etching solution is dispensed onto the surface of the wafer 404 within the spin chamber using a delivery system 406. For example embodiment 400, the LED array 402 may be a single wavelength or may be multiple wavelengths by interspersing different emitters within the array. The power of each emitter may be adjusted in real time to control the illumination intensity across the wafer surface. For one embodiment, the LED array 402 is mechanically synchronized with the motion of the wafer 404, as indicated by arrows 403 and 405. For another embodiment, the LED array 402 remains stationary while the intensity of each emitter is synchronized with the motion of the wafer 404. Additional variations may also be implemented.
Fig. 4B provides an example embodiment 450 of delivering illumination by one or more laser sources 452/456 of a liquid etching solution dispensed on a surface of a substrate of a microelectronic workpiece, such as a semiconductor wafer 404. Prior to irradiation, a liquid etching solution is dispensed onto the surface of the wafer 404 within the spin chamber using a delivery system 406. And then irradiated using a single laser or multiple laser sources 452/456. For example, multiple laser sources 452/456 may be used where it is desired to illuminate the wafer 404 with multiple wavelengths. The laser beam from the laser source 452/456 is rastered across the wafer surface using steering optics 454/458. The dwell time of the laser spot on a single point on the surface of the wafer 404 controls the etch enhancement at that point. The movement of the laser beam may be synchronized with the movement of the wafer 404, as represented by arrows 405, 455, and 459.
For further additional embodiments, etch uniformity over a relatively large surface area of a substrate of a microelectronic workpiece can be improved by a feed-forward technique. For example, the topography of the surface of the substrate and/or the layer thickness may be measured over a selected surface area, and the amount of etching for different areas within the surface area may be determined based on these measurements and the desired results. For example, if a smooth surface is desired, spatial and/or temporal control of the UV light illumination can be used to adjust the local etch rate to make the peaks and valleys within the topology uniform to achieve the desired target surface parameters. Feed forward control thus provides a technique for compensating for non-uniform layer thicknesses and/or other variations across a microelectronic workpiece.
Fig. 5A is a process flow diagram of an example embodiment 500 of using irradiation to adjust reactants within a liquid etching solution to improve etch uniformity for etching material on a surface of a substrate of a microelectronic workpiece. In block 502, a substrate of a microelectronic workpiece is received and has material to be etched from a surface of the substrate. In block 504, a liquid etching solution is applied to a surface of a substrate, and the liquid etching solution has a first reactant level with respect to the material. In block 506, a liquid etching solution is irradiated to have a second reactant level with respect to the material, and the second level is greater than the first level. In block 508, the material is oxidized with a liquid etching solution to form an oxidized material. In block 510, the oxide material is removed. It should be noted that additional and/or different steps may also be used while still utilizing the illumination techniques described herein.
Figure 5B is a process flow diagram of an example embodiment 550 of using irradiation to form hydroxyl radicals within a liquid etching solution with hydrogen peroxide to improve etch uniformity for etching polycrystalline metal on a surface of a substrate of a microelectronic workpiece. In block 552, a substrate of a microelectronic workpiece is received and the substrate has polycrystalline metal to be etched from a surface of the substrate. In block 554, a liquid etching solution comprising hydrogen peroxide is applied to a surface of the substrate, and the liquid etching solution has a first reactant level with respect to the polycrystalline metal. In block 556, the liquid etching solution is irradiated to cause formation of hydroxyl radicals from the hydrogen peroxide, and the formation of hydroxyl radicals at least partially causes the liquid etching solution to have a second reactant level with respect to the polycrystalline metal. Further, the second reactant level is greater than the first reactant level. In block 558, the polycrystalline metal is oxidized with a liquid etching solution to form an oxidized metal. In block 560, the oxidized metal is removed. It should be noted that additional and/or different steps may also be used while still utilizing the illumination techniques described herein.
Fig. 6 is a process flow diagram of an example embodiment 600 of using illumination to adjust a reactant within an etching solution (e.g., at least one of a gaseous etching solution, a liquid etching solution, or a combination thereof) to improve etch uniformity for etching material on a surface of a substrate of a microelectronic workpiece. In block 602, a substrate of a microelectronic workpiece is received and the substrate has material to be etched from a surface of the substrate. In block 604, an etching solution is applied to a surface of a substrate, and the etching solution has a first reactant level with respect to the material. In block 606, the etching solution and the surface of the material are exposed to radiation to form a modified material layer on the surface of the material, and the exposure causes the etching solution to have a second reactant level with respect to the material that is greater than the first level. In block 608, the modified material layer is removed. It should be noted that additional and/or different steps may also be used while still utilizing the illumination techniques described herein.
Fig. 7 is a process flow diagram of an example embodiment 700 for polishing a material using irradiation of an etching solution (e.g., at least one of a gaseous etching solution, a liquid etching solution, or a combination thereof). In block 702, a material to be polished is received. In block 704, an etching solution is applied to a surface of a material, and the etching solution has a first reactant level with respect to the material. In block 706, the etching solution and the surface of the material are exposed to radiation to form a modified material layer on the surface of the material, and the exposure causes the etching solution to have a second reactant level with respect to the material that is greater than the first level. In block 708, the modified material layer is removed to provide the material with a polished surface. The polished surface is polished because it has less surface variation than the surface of the original material being etched. It should be noted that additional and/or different steps may also be used while still utilizing the illumination techniques described herein.
It is further noted that the techniques described herein may be used with a wide range of processing systems, equipment, and platforms. For example, these techniques may be used in a wet etch processing system as shown in FIG. 8A, and the wet etch processing system may be used in combination with a dry etch processing system as shown in the processing platform embodiment of FIG. 8B. Other variations may also be implemented.
Figure 8A is a block diagram of one example embodiment of a wet etch processing system 800 that may be used in conjunction with the disclosed techniques to etch material on a surface of a substrate 806. The wet etch processing system 800 includes a wet process chamber 810. The wet process chamber 810 may be a pressure controlled chamber. A substrate 806, in one example a semiconductor wafer, is held on a substrate holder 808, such as an electrostatic chuck. The substrate holder 808 may also be configured to rotate at a controlled speed.
A delivery system 802 for a liquid etching solution and an illumination system 804 are used with the wet processing chamber 810. The delivery system 802 can include a reservoir for holding a liquid etching solution and a liquid delivery tube having a dispensing nozzle located within the wet processing chamber 810. The delivery system 802 can be used to dispense a liquid etching solution onto the surface of the substrate 806. As described herein and with respect to fig. 4A-4B, the liquid etching solution is irradiated using an illumination system 804, which may be an LED array or other illumination device that provides light at a single wavelength or multiple wavelengths. Further, such irradiation may be selective, synchronized with rotation of the substrate holder 808, and/or otherwise delivered to irradiate the liquid etching solution to adjust the reactant level within the liquid etching solution as described herein.
As described herein, the disclosed embodiments provide beneficial results when used to etch polycrystalline structures (such as polycrystalline metallic cobalt). Other polycrystalline materials and polycrystalline metals, as well as other materials, may also be etched using the illumination techniques described herein. For example, additional polycrystalline materials and compounds that may be etched include ruthenium, tungsten, titanium, tantalum, titanium nitride, tantalum nitride, and/or other materials.
The components of the wet etch processing system 800 may be coupled to and controlled by a controller 812, which in turn may be coupled to a corresponding memory storage unit and user interface (not shown). Various machining operations may be performed via the user interface, and various machining recipes and operations may be stored in the storage unit. Accordingly, a given substrate 806 may be processed within the wet process chamber 810 by various techniques. It will be appreciated that the controller 812 may be coupled to various components of the wet etch processing system 800 to receive inputs from and provide outputs to such components.
The controller 812 may be implemented in a variety of ways. For example, the controller 812 may be a computer. In another example, the controller may include one or more programmable integrated circuits programmed to provide the functionality described herein. For example, one or more processors (e.g., microprocessors, microcontrollers, central processing units, etc.), programmable logic devices (e.g., Complex Programmable Logic Devices (CPLDs)), Field Programmable Gate Arrays (FPGAs), etc.), and/or other programmable integrated circuits may be programmed with software or other programming instructions to implement the functionality of the plasma processing scheme that is disabled. It is further noted that software or other programming instructions may be stored in one or more non-transitory computer-readable media (e.g., memory storage devices, flash memory, DRAM memory, reprogrammable storage devices, hard drives, floppy disks, DVDs, CD-ROMs, etc.), and that the software or other programming instructions, when executed by a programmable integrated circuit, cause the programmable integrated circuit to perform the processes, functions, and/or capabilities described herein. Other variations may also be implemented.
Fig. 8B is a block diagram of an example embodiment for a platform 850 that includes a wet etch processing system 800 and a dry etch processing system 852. As described herein, the wet etch processing system 800 dispenses a liquid etching solution onto a material to be etched and then irradiates the liquid etching solution to adjust the level of reactants within the liquid etching solution. The dry etch processing system 852 may implement any desired dry etch process that etches a substrate or removes material from a substrate being processed. In operation, the dry etch processing system 852 etches material on a substrate using a dry etch chemistry.
It should be noted that the dry etch processing system 852 may implement any of a variety of dry etch processes, such as a plasma etch process, a Reactive Ion Etch (RIE) process, a Chemical Vapor Etch (CVE) process, an Atomic Layer Etch (ALE) process, and/or other dry etch processes. Further, the dry etching process may be performed before or after the wet etching process. For example, a dry etch process may be performed in a dry etch process chamber of the dry etch processing system 852 to remove material from the substrate to produce the first surface roughness. The substrate is then transferred (via the transfer module 854) into a wet etch process chamber of the wet etch processing system 800 to perform a wet etch process to produce a second surface roughness, wherein the second surface roughness is less than the first surface roughness. It should be further noted that a plurality of dry etching processes and a plurality of wet etching processes may be performed by transferring the substrate as needed using the transfer module 854. Other variations may also be implemented.
To facilitate processing of substrates within the dry etch processing system 852 and the wet etch processing system 800, a transfer module 854 and an isolation pass-through module 856 can also be coupled between the two systems 800/852. The transfer module 854 is configured to move substrates between the dry etch processing system 852 and the wet etch processing system 800, as indicated by arrow 858. An isolation pass-through module 856 is disposed between the transfer module 854 and the wet etch processing system 800 to separate the ambient environment of the transfer module 854 from the ambient environment of the wet etch processing system 800. The substrate may then be moved between the dry etch processing system 852 and the wet etch processing system 800 without exposing the substrate to potential contaminants present outside of the processing system 800/852. This movement may also be controlled by a controller, such as controller 812 described in connection with fig. 8A.
Further exemplary embodiments that may be used for the dry etch processing system 852, the wet etch processing system 800, the transfer module 854, and the isolation pass-through module 856 are described in the following applications: U.S. provisional patent application serial No. 62/794,315 entitled "Platform and Method for Operating for Integrated End-to-End Gate Contact Process" filed 2019, month 1, 18; us provisional application serial No. 62/787,607 entitled "Self-sensing and calibrating Heterogeneous Platform and Method for using same" filed 1, 2.2019; us provisional application serial No. 62/787,608 entitled "Self-sensing and calibrating Heterogeneous Platform and Method for using same" filed 1, 2.2019; U.S. provisional application serial No. 62/788,195 entitled "Substrate Processing Tool with Integrated Metrology and Method of using" filed on 4.1.2019; AND us patent application serial No. 16/356,451 entitled "PLATFORM AND METHOD OF OPERATING FOR INTEGRATED END-TO-END GATE CONTACT processes," filed on 18/3/2019, each OF which is incorporated herein by reference in its entirety.
It should be noted that one or more deposition processes may be used to form the material layers described herein. For example, one or more depositions may be performed using Chemical Vapor Deposition (CVD), plasma enhanced CVD (pecvd), Physical Vapor Deposition (PVD), Atomic Layer Deposition (ALD), and/or other deposition processes. For plasma deposition processes, precursor gas mixtures (including but not limited to hydrocarbons, fluorocarbons, or nitrogen-containing hydrocarbons) may be used in combination with one or more diluent gases (e.g., argon, nitrogen, etc.) under a variety of pressure, power, flow, and temperature conditions. The photolithography process with respect to the Photoresist (PR) layer may be performed using optical lithography, Extreme Ultraviolet (EUV) lithography, and/or other photolithography processes. The etch process may be performed using a plasma etch process, a discharge etch process, Atomic Layer Etching (ALE), and/or other desired etch processes. For example, the plasma etch process may be performed using a plasma comprising fluorocarbon, oxygen, nitrogen, hydrogen, argon, and/or other gases. In addition, the operating variables for the process steps may be controlled to ensure that the CD (critical dimension) target parameter of the via is achieved during via formation. The operating variables may include, for example, chamber temperature, chamber pressure, flow rate of gases, frequency and/or power applied to the electrode assembly while generating the plasma, and/or other operating variables used for processing steps. Variations may also be implemented while still utilizing the techniques described herein.
It is noted that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, but does not mean that they are present in every embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. In other embodiments, various additional layers and/or structures may be included, and/or the described features may be omitted.
As used herein, "microelectronic workpiece" generally refers to an object being processed according to the present invention. The microelectronic workpiece may comprise any material portion or structure of a device, particularly a semiconductor or other electronic device, and may be, for example, a base substrate structure, such as a semiconductor substrate, or a layer, such as a thin film, overlying or on a base substrate structure. Thus, the workpiece is not intended to be limited to any particular underlying, or overlying layer, patterned or unpatterned, but is contemplated to include any such layer or underlying structure, and any combination of layers and/or underlying structures. The following description may refer to a particular type of substrate, but this is for illustration purposes only and not for limitation purposes.
As used herein, the term "substrate" means and includes the base material or construction upon which the material is formed. It should be understood that the substrate may comprise a single material, multiple layers of different materials, one or more layers having regions of different materials or different structural regions therein, etc. These materials may include semiconductors, insulators, conductors, or combinations thereof. For example, the substrate may be a semiconductor substrate, a base semiconductor layer on a support structure, a metal electrode or a semiconductor substrate having one or more layers, structures or regions formed thereon. The substrate may be a conventional silicon substrate or other bulk substrate comprising a layer of semiconductor material. As used herein, the term "bulk substrate" refers to a silicon wafer and includes not only silicon wafers, but also silicon-on-insulator ("SOI") substrates, such as silicon-on-sapphire ("SOS") substrates and silicon-on-glass ("SOG") substrates, epitaxial layers of silicon on a base semiconductor substrate, and other semiconductor or optoelectronic materials such as silicon germanium, gallium arsenide, gallium nitride, and indium phosphide. The substrate may be doped or undoped.
Systems and methods for processing a microelectronic workpiece are described in various embodiments. One skilled in the relevant art will recognize that the various embodiments may be practiced without one or more of the specific details, or with other alternative and/or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Similarly, specific numbers, materials and configurations are set forth for purposes of explanation in order to provide a thorough understanding of the present invention. However, the invention may be practiced without the specific details. Furthermore, it should be understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.
Further modifications and alternative embodiments of the described systems and methods will be apparent to those skilled in the art in view of this description. Accordingly, it will be appreciated that the described systems and methods are not limited by these example arrangements. It is to be understood that the forms of the systems and methods shown and described herein are to be taken as example embodiments. Various changes may be made in the embodiments. Thus, although the invention is described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of the present invention. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and such modifications are intended to be included within the scope of present invention. Further, any benefits, advantages, or solutions to problems that are described herein with regard to specific embodiments are not intended to be construed as a critical, required, or essential feature or element of any or all the claims.

Claims (22)

1. A processing system for performing a wet etch process on a substrate, the processing system comprising:
a wet process chamber configured to perform a wet etching process;
a substrate holder located within the wet process chamber, the substrate holder configured to support a substrate;
a delivery system arranged to supply a liquid etching solution to the substrate, the liquid solution having a first reactant level with respect to a material on a surface of the substrate;
an illumination system arranged to illuminate the liquid etching solution to cause the etching solution to have a second reactant level for the material different from the first level; and
a controller coupled to the delivery system to control delivery of the liquid etching solution and coupled to the illumination system to control illumination output by the illumination system.
2. The processing system of claim 1, wherein the controller is configured to control the illumination system and the delivery system to etch the material in a cyclical manner.
3. The processing system of claim 1, wherein the liquid etching solution, when irradiated, oxidizes the surface of the material to form an oxidized material as a modified layer.
4. The processing system of claim 3, wherein a uniform layer of oxide material is formed as the modified layer, and wherein the liquid etching solution further dissolves the oxide material.
5. The processing system of claim 4, wherein the liquid etching solution comprises an aqueous solution comprising hydrogen peroxide and citrate.
6. The processing system of claim 3, wherein the delivery system is further configured to deliver an aqueous solution comprising a complexing agent to dissolve the oxidizing material.
7. The processing system of claim 6, wherein the complexing agent comprises at least one of citrate, ethylenediamine, ethylenediaminetetraacetic acid (EDTA), malic acid, oxalic acid, glycine, alanine, or iminodiacetic acid.
8. The processing system of claim 1, wherein the material to be etched comprises a polycrystalline material.
9. The processing system of claim 8, wherein the polycrystalline material comprises at least one of polycrystalline metal, polycrystalline cobalt, ruthenium, tungsten, titanium, tantalum, titanium nitride, or tantalum nitride.
10. The processing system of claim 1, wherein the illumination system is configured to selectively illuminate the liquid etching solution.
11. The processing system of claim 10, wherein the illumination system is configured to selectively illuminate the liquid etching solution with Ultraviolet (UV) light in one or more on/off modes.
12. The processing system of claim 10, wherein the illumination system is configured to selectively illuminate with two or more different colors of light.
13. The processing system of claim 1, wherein the controller is configured to control the illumination system to cause different exposures to different regions of the liquid etching solution to provide different amounts of etching to materials within the different regions.
14. The processing system of claim 13, wherein the different exposures are based on measurements of at least one of a topology of a surface of the material or a thickness of the material.
15. A platform for etching a substrate, the platform comprising:
a dry etch processing system for etching the polycrystalline material on the substrate using dry etch chemistry;
a wet etch processing system for etching the polycrystalline material to mitigate roughness of the polycrystalline material caused by the dry etch chemistry, the wet etch processing system comprising:
a wet process chamber configured to perform a wet etching process;
a substrate holder located within the wet process chamber, the substrate holder configured to support a substrate;
a delivery system arranged to supply a liquid etching solution to the substrate, the liquid solution having a first reactant level with respect to the polycrystalline material;
an illumination system arranged to illuminate the liquid etching solution to cause the etching solution to have a second reactant level for the polycrystalline material different from the first level; and
a controller coupled to the delivery system to control delivery of the liquid etching solution and coupled to the illumination system to control illumination output by the illumination system;
a transfer module coupled to move the substrate between the dry etch processing system and the wet etch processing system; and
an isolation pass-through module coupled between the transfer module and the wet etch processing tool, the isolation pass-through module separating an ambient environment of the transfer module from an ambient environment of the wet etch processing system.
16. The platform of claim 15, wherein the controller is configured to control the illumination system and the transport system to etch the polycrystalline material in a cyclical manner.
17. The platform of claim 15, wherein the liquid etching solution, when irradiated, oxidizes the surface of the polycrystalline material to form an oxidized material as a modified layer.
18. The platform of claim 15, wherein the liquid etching solution comprises an aqueous solution comprising hydrogen peroxide, and wherein the illumination comprises Ultraviolet (UV) light.
19. The platform of claim 15, wherein the dry etch processing system implements one or more dry etch processes.
20. The platform of claim 19, wherein the one or more dry etch processes comprise at least one of a plasma etch process, a Reactive Ion Etch (RIE) process, a Chemical Vapor Etch (CVE) process, or an Atomic Layer Etch (ALE) process.
21. The platform of claim 15, wherein the dry etch processing system is configured to etch the polycrystalline material to produce a first surface roughness, and wherein the wet etch process chamber is configured to adjust the first surface roughness to a second surface roughness less than the first surface roughness.
22. The platform of claim 21, wherein the controller is configured to control the illumination system to cause different exposures to different regions of the liquid etching solution based on measurements of at least one of a topology of a surface of the material or a thickness of the material to provide different amounts of etching for the polycrystalline material.
CN201980089026.9A 2018-12-14 2019-12-10 Processing system and platform for reducing material roughness using irradiated etching solution Pending CN113302730A (en)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
US201862779604P 2018-12-14 2018-12-14
US62/779,604 2018-12-14
US16/287,669 US10896824B2 (en) 2018-12-14 2019-02-27 Roughness reduction methods for materials using illuminated etch solutions
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US16/402,634 US20200075351A1 (en) 2018-09-04 2019-05-03 Processing systems and platforms for roughness reduction of materials using illuminated etch solutions
US16/402,634 2019-05-03
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