JP2022515350A - Processing systems and platforms for reducing material roughness using irradiated etching solutions - Google Patents

Abstract

Embodiments of processing systems and platforms that irradiate an etching solution to provide controlled etching of the material are described. The treatment system and platform deposit a liquid etching solution on top of the material to be etched and irradiate the liquid etching solution to adjust the level of the reactants. The liquid-etched solution has a first level of reactants, and irradiation causes the liquid-etched solution to have a second level of reactants different from the first level. The material is modified with the irradiated etching solution, and the modified material is removed. Feeding, exposure and removal can be repeated to provide periodic etching. In addition, oxidation and dissolution can occur simultaneously or in multiple steps. The material to be etched can be a polycrystalline material, a polycrystalline metal and / or other material. One liquid etching solution may contain hydrogen peroxide which is irradiated to form hydroxyl radicals.

Description

Related Applications This application is a US provisional patent application No. 62 / 779,604 and a November 4, 2018 application entitled "ROUGHNESS REDUCTION METHODS FOR WET ETCH OF POLYCRYSTALLINE MATERIALS" filed on December 14, 2018. US provisional patent application No. 62 / 726,603, entitled "PHOTONICALLY TUNED ETCHANT REACTIVITY", and "ROUGHNESS REDUCTION METHODS FOR MATERIALS USING ILLUSOMENT" US ING ILLUMISUTE, US patent application, filed February 27, 2019. Publication No. 16 / 287,669 and US patent No. 402 to "PROCESSING SYSTEMS AND PLATFORMS FOR ROUGHNESS REDUCTION OF MATERIALS USING ILLUMINATED ETCH SOLUTIONS" filed May 3, 2019. Priority is also claimed, each of which is incorporated herein by reference in its entirety.

The present disclosure relates to a method of manufacturing a microelectronic workpiece, comprising etching a material layer on the microelectronic workpiece.

Device formation within a microelectronic workpiece typically involves a series of manufacturing techniques for forming, patterning and removing multiple layers of material on the substrate of the microelectronic workpiece. Etching is often used to remove the material layer from the surface of the substrate. The characteristic size of the material to be etched continues to shrink to match the electronic elements formed on the microelectronic workpiece, making it even more difficult to control etching uniformity on macroscopic and microscale scales. It has become. Conventional wet etching processes using liquid etching solutions often do not allow accurate control of etching behavior at the nanoscale level. This lack of control becomes a problem when removing small amounts of material and / or when a smooth surface finish is required.

Controlling roughness during the etching process of polycrystalline materials is a particularly difficult task. A polycrystalline material exhibits a change in reactivity with an etchant, depending on the surface crystallographic orientation of the polycrystalline material. The polycrystalline material also exhibits a change in reactivity to the etchant at the grain boundaries and defect sites of the polycrystalline material. This variable reactivity results in undesired etching variability and surface roughness in conventional wet etching processes.

FIGS. 1A-1B show diagrams associated with such conventional etching solutions and related problems with variable reactivity and undesired etching variability.

First, with reference to FIG. 1A (conventional technique), an exemplary embodiment 100 of a conventional etching process method is shown. The liquid etching solution 106 is dropped onto the material 104 on the surface of the substrate 108 of the microelectronic workpiece. In the exemplary embodiment 100, the material 104 to be etched is cobalt (Co), which material 104 is already formed on the surface of the substrate 108. In the exemplary embodiment 100, the liquid etching solution 106 provides an oxidative dissolution etching mechanism. In this oxidative dissolution etching mechanism, the material 104 is oxidized by the liquid etching solution 106 and then dissolved by the liquid etching solution 106.

The conventional oxidative dissolution etching mechanism for cobalt causes significant roughness and pitting corrosion. In this conventional method, cobalt etching is an oxidation / dissolution mechanism in which an oxidizing agent (for example, hydrogen peroxide) oxidizes cobalt (Co) at an oxidation rate constant k _ox to form CoO _x , as shown by an arrow 110. Driven by. CoO _x is then dissolved in solution by complex formation with an etchant molecule (eg, citrate anion) at a dissolution rate constant _cd , as indicated by arrow 112. In this conventional method, k _ox is less than k _d (k _ox <k _d ), and this condition causes non-uniform etching at the grain boundaries of polycrystalline cobalt, resulting in pitting corrosion and roughness on the surface.

FIG. 1B (previous technique) shows a surface image 150 showing the surface pitting and roughness described above due to the undesired etching variability associated with conventional oxidative dissolution schemes. In contrast, an ideal wet etching process provides a constant etching rate that is independent of the surface chemistry (eg, grain boundaries) of the material to be etched.

Embodiments that use irradiation of the etching solution to provide controlled etching of the material are described below. The disclosed processing systems and platforms deposit a liquid etching solution on top of the material to be etched and irradiate the liquid etching solution to adjust the level of the reactants. The material to be etched can be, for example, a polycrystalline material, a polycrystalline metal and / or other material to be etched. The disclosed embodiments use irradiation as a tool to control the reactivity of the etchant in the etching solution in contact with the material, thereby allowing the etching behavior to be modified. Chemical composition and other parameters can also be used partially to control etching behavior and surface morphology and chemical properties after etching. The disclosed embodiments thereby control and / or reduce surface roughness during etching of materials such as polycrystalline materials at both microscopic and macroscopic levels. These results are achieved through irradiation of the etching solution dropped onto the surface of the material, which provides a point-of-use production of highly reactive etchants that etch the material independently of the surface chemistry of the material. In one exemplary embodiment, the liquid etching solution is an aqueous solution containing hydrogen peroxide, and hydroxyl radicals are generated by irradiation with ultraviolet light or the like to form highly reactive etchants. Different or additional features, variants and embodiments may be implemented and related systems and methods may be utilized.

In one embodiment, a processing system for performing a wet etching process on a substrate is disclosed, the processing system being configured to support a wet processing chamber configured to perform the wet etching process and the substrate. A substrate holder in a wet processing chamber and a supply system arranged to supply the substrate with a liquid etching solution, the liquid etching solution having a first level reactant with respect to the material on the surface of the substrate. The supply system and the supply of the liquid etching solution are arranged to irradiate the liquid etching solution so that the etching solution has a second level of reactant different from the first level for the material. Includes a controller coupled to the supply system to control and coupled to the irradiation system to control the irradiation output by the irradiation system.

In an additional embodiment, the controller is configured to control the irradiation system and the supply system to etch the material periodically.

In an additional embodiment, the liquid etching solution, when irradiated, oxidizes the surface of the material to form an oxidizing material as a modified layer. In a further embodiment, a uniform layer of oxidizing material is formed as a modified layer and the liquid etching solution further dissolves the oxidizing material. In a further embodiment, the liquid etching solution comprises an aqueous solution containing hydrogen peroxide and citrate. In a further embodiment, the supply system is further configured to supply an aqueous solution containing a complexing agent for dissolving the oxidizing material. In a further embodiment, 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 an additional embodiment, the irradiation system is configured to selectively irradiate the liquid etching solution. In a further embodiment, the irradiation system is configured to selectively irradiate the liquid etching solution with ultraviolet (UV) light in one or more on / off patterns. In a further embodiment, the irradiation system is configured to selectively irradiate with two or more different colored lights.

In an additional embodiment, the controller is configured to produce different exposures to different regions of the liquid etching solution and control the irradiation system to provide different amounts of etching to the material within different regions. .. In a further embodiment, the different exposures are based on at least one measurement of the surface topology of the material or the thickness of the material.

In one embodiment, a platform for etching a substrate is disclosed, in which a dry etching process system for etching a polycrystalline material on a substrate by dry etching chemistry and the roughness of the polycrystalline material generated by the dry etching chemistry are disclosed. Wet etching system that etches polycrystalline material for relaxation, transfer module coupled to move substrate between dry etching system and wet etching system, transfer module and wet etching tool Insulation penetration module coupled between the above, including an insulation penetration module that separates the ambient environment of the transfer module from the ambient environment of the wet etching process system. In this platform, the wet etching system is a wet processing chamber configured to perform a wet etching process, a substrate holder in the wet processing chamber configured to support the substrate, and liquid etching on the substrate. A supply system arranged to supply the solution, wherein the liquid etching solution has a first level reactant for the polycrystalline material, the supply system and the etching solution is the first for the polycrystalline material. An irradiation system arranged to irradiate the liquid etching solution so as to have a second level of reactant different from the level, and coupled to the supply system to control the supply of the liquid etching solution, and by the irradiation system. Includes a controller coupled to the irradiation system to control the output irradiation.

In an additional embodiment, the controller is configured to control the irradiation system and the supply system to periodically etch the polycrystalline material.

In an additional embodiment, the liquid etching solution, when irradiated, oxidizes the surface of the polycrystalline material to form an oxidizing material as a modified layer. In a further additional embodiment, the liquid etching solution comprises an aqueous solution containing hydrogen peroxide and the irradiation comprises ultraviolet (UV) light.

In an additional embodiment, the dry etching system performs one or more dry etching processes. In a further embodiment, the one or more dry etching processes include at least one of a plasma etching process, a reactive ion etching (RIE) process, a chemical gas phase etching (CVE) process, or an atomic layer etching (ALE) process.

In an additional embodiment, the dry etching system is configured to etch the polycrystalline material to provide a first surface roughness, and the wet etching chamber has a first surface roughness, first. It is configured to adjust to a second surface roughness that is smaller than the surface roughness of 1. In a further embodiment, the controller produces different exposures to different regions of the liquid etching solution to give different amounts to the polycrystalline material based on the surface topology of the material or at least one measurement of the thickness of the material. It is configured to control the irradiation system to provide etching.

Different or additional features, variants and embodiments may be implemented and related systems and methods may be utilized.

A more detailed understanding of the invention and its advantages can be obtained by reference to the following description in conjunction with the accompanying drawings in which the same reference number exhibits the same features. However, because the disclosed concepts are applicable to other equally effective embodiments, the accompanying drawings show only exemplary embodiments of the disclosed concepts and are therefore considered to limit the scope of the invention. Please note that it should not be.

(Prior Technique) Shown is an explanatory diagram associated with a conventional etching solution that causes problems associated with variable reactivity and undesired etching variability. (Prior Technique) FIG. 1A shows a representative surface image of pitting corrosion and roughness of the surface due to undesired etching variability associated with the conventional oxidative dissolution method of FIG. 1A (previous technique). Shown is an exemplary embodiment that achieves control of etching rate and uniformity, preferably real-time control, of etching a material on the surface of a substrate of a microelectronic workpiece using irradiation with a liquid etching solution. FIG. 2A shows a representative surface image of a smooth surface realized due to the improvement of etching uniformity associated with the irradiation method of FIG. 2A. A representative surface image of the roughness before the periodic treatment mode in which the oxidation and dissolution reactions are separated is shown. The representative surface image in the state where the roughness is reduced as compared with FIG. 3A after the etching process using the periodic process mode is shown. A representative diagram of the AFM (atomic force microscopy) surface roughness profile before and after the etching process represented by the surface images of FIGS. 3A and 3B is shown. Shown is an exemplary embodiment 400 of a scanner solution that uses a light emitting diode (LED) array to irradiate a liquid etching solution dropped onto the surface of a substrate of a microelectronic workpiece. Provided is an exemplary embodiment in which irradiation of a liquid etching solution dispensed onto the surface of a substrate of a microelectronic workpiece is emitted by one or more laser sources. A processing flow diagram of an exemplary embodiment that improves etching uniformity when etching a material on the surface of a substrate of a microelectronic workpiece by adjusting the reactants in a liquid etching solution using irradiation. Is. By forming hydroxyl radicals in a liquid etching solution containing hydrogen peroxide using irradiation, the uniformity of etching when etching a polycrystalline metal on the surface of a substrate of a microelectronic workpiece is improved. It is a processing flow diagram of an exemplary embodiment. Irradiation is used to etch the material on the surface of the substrate of the microelectronic workpiece by adjusting the reactants in the etching solution (eg, at least one of a gas etching solution, a liquid etching solution or a combination thereof). It is a processing flow diagram of an exemplary embodiment which improves the uniformity of etching at the time. FIG. 6 is a processing flow diagram of an exemplary embodiment in which a material is polished using irradiation with an etching solution (eg, a gas etching solution, a liquid etching solution, or at least one of a combination thereof). It is a block diagram of an exemplary embodiment of a wet etching process system including a liquid etching solution supply system and an irradiation system that can be used with respect to the disclosed technique. FIG. 3 is a block diagram of an exemplary embodiment of a processing platform comprising a wet etching processing system and a dry etching processing system that can be used with respect to the disclosed techniques.

As described herein, irradiation is used to adjust the reactivity of the etchant to perform controlled etching of materials such as polycrystalline materials or metals to achieve surface chemistry-independent etching of the material. Methods and related processing systems and platforms are disclosed. Other advantages and embodiments may still be realized while utilizing the processing techniques described herein.

Controlling the uniformity of nanoscale etching helps to minimize elemental failure of microelectronic devices and circuits formed on microelectronic workpieces. In many cases, conventional wet etching chemistry cannot accurately control etching of materials such as polycrystalline materials and metals. For example, variable etching rates at grain boundaries and / or different crystal facets for polycrystalline materials can lead to surface roughness during etching. The disclosed embodiments provide a method of achieving etching uniformity on both microscopic and macroscopic scales by point-of-use generation of highly reactive etchants with controlled irradiation. In one embodiment, the disclosed embodiments provide these advantageous results when used for etching metal polycrystalline structures such as polycrystalline metallic cobalt. Other materials, as well as other polycrystalline materials and metals, can be etched using the irradiation techniques described herein.

In one embodiment, highly reactive hydroxyl radicals (HO ^* ) are produced as etchants for the polycrystalline material through irradiation of the surface of the polycrystalline material with a suitable liquid etching solution. Hydroxyl radicals are strong oxidants and etch polycrystalline materials at room temperature. In one embodiment, hydroxyl radicals are generated using ultraviolet (UV) light irradiation of an aqueous solution of hydrogen peroxide (H ₂ O ₂ ) in contact with the material to be etched. Irradiation can also be selectively point-of-use to better control the etching process and speed.

In this point of use solution, if surface etching is desired, one or more areas of the liquid etching solution (eg, an aqueous solution of hydrogen peroxide) will be selectively irradiated and the other areas that do not require etching will not be irradiated. .. For example, irradiation with hydrogen peroxide forms hydroxyl radicals, resulting in increased levels of reactants. However, when irradiation is stopped, hydroxyl radicals have a short lifetime and are rapidly reabsorbed in aqueous solution. For example, the lifetime of hydroxyl radicals after stop of irradiation is less than 2-5 microseconds. Thus, by adjusting the reactivity of the etchant using selective UV irradiation, the thermodynamics and kinetics of the etching reaction in selected regions of the liquid etching solution can be altered. Combining high reactivity with the microsecond-level lifetime of hydroxyl radicals allows rapid and / or near-instantaneous oxidation of the material surface layer independent of local surface reactivity. The surface is smoothly etched by removing the oxide layer later. Further, by spatially adjusting the UV light intensity in the feed-forward process during the irradiation process, large-scale etching uniformity can be obtained. Other variants may still be implemented utilizing the techniques described herein.

One of the significant advantages of the disclosed embodiments is that the reactivity of the etchant can be adjusted almost instantaneously on the fly using controlled irradiation. This ability to adjust allows access to a wider parameter space on the potential pH diagram (ie, Pourbaix diagram) of the photosensitive etchant without the need to mix additional reactants and chemicals. This simplifies the processing chemistry and reduces the cost for the wet etching process.

As described herein, the disclosed embodiments provide one or more of the following: (1) Real-time and point-of-use adjustment of the reactivity of the etchant allows the etching behavior to be adjusted without the need for additional chemical mixing or invasive conditions, and (2) highly reactive transients. By bringing a targeted excited state to the surface of a microelectronic workpiece (eg, a semiconductor wafer), the short lifetime of this state is utilized to etch the surface using the excited state (3) of the polycrystalline material. By controlling the surface roughness during etching, (4) temporal and spatial control of the etching rate on the surface of the microelectronic workpiece is possible, and / or (5) feedforward control is performed to perform the microelectronic work. Compensates for non-uniform layer thickness throughout the piece. Further and / or different advantages and features can also be provided by the techniques described herein.

2A-2B and 3A-3C are embodiments disclosed in which irradiation is used to adjust the etching rate of a liquid etching solution dropped onto a polycrystalline material etched on the surface of a microelectronic workpiece. The associated explanatory diagram is shown. Further and / or different embodiments may be implemented utilizing the techniques described herein.

It is noted that the irradiation described herein can be selective irradiation performed in real time to perform point-of-use control. Liquid etching solutions typically have set reactivity and etching rates for a given material, based on the composition and temperature of the solution. The disclosed embodiments adjust the etching behavior of a liquid etching solution having a given composition at a given temperature in real time. Also disclosed embodiments allow for adjustment of etching rates with respect to the location and / or position of the material on the surface of the microelectronic workpiece and, using feedforward control, are higher across the microelectronic workpiece. The uniformity can be improved.

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 place the solution at a single point on the Pourbaix diagram. The parameters are set by the solution composition. This solution composition uniquely sets the thermodynamic equilibrium that appears when the solution is placed in contact with the surface to be etched, as well as the solubility of the etching product. In this way, the etching behavior of the system is determined.

In contrast, the disclosed embodiments provide a wet etching process that provides the desired etching behavior by adjusting the reactivity of the etchant and / or the potential of the etching solution using irradiation. In embodiments herein, the etching solution comprises a photosensitive compound that undergoes an irradiation-based photochemical reaction that produces reactive etchants (eg, radicals or radical ions). The liquid etching solution may also contain additional components that solubilize or volatilize the etching product.

In one embodiment, hydroxyl radical (HO ^* ) is used as a transient excited state species and is produced from the photolysis of hydrogen peroxide. Other examples include singlet oxygen, excited state molecules, radicals, dimers, complexes and / or other materials having the property of producing and / or adjusting reactive etchants through irradiation. Not limited to. For example, similar reactive species can be produced from photolysis of an aqueous solution of ozone or hypochlorous acid. Other variants may also be implemented.

In one exemplary mounting embodiment, the disclosed embodiments are used to reduce the roughness of the polycrystalline metal material in etching. In a further exemplary embodiment, the polycrystalline metal material is cobalt.

Wet etching of polycrystalline materials is often achieved by an oxidative dissolution mechanism. The etching solution contains an oxidizing agent and a reactant that promote the dissolution of the etching product. Etching behavior (eg, etching rate, etching uniformity), and final surface morphology depend on the chemical reactions that occur on the surface of the material to be etched. Variable etching rates on polycrystalline materials are a common problem with conventional wet etching processes in that this variability often results in undesired surface morphology such as roughness and pitting corrosion. By adjusting the oxidation and dissolution reaction rates through irradiation described herein, preferably in real time, the etching behavior can be modified to achieve uniform etching.

Hydrogen peroxide is an etchant commonly used in wet etching processes. As recognized in this embodiment, irradiation of hydrogen peroxide with light with a wavelength (λ) less than 560 nanometers (nm) (ie, λ <560 nm) results in quantitative photolysis to form hydroxyl radicals. .. For example, UV light having a wavelength of 10 nm to 400 nm (for example, 10 nm ≦ λ ≦ 400 nm) can be used for this irradiation. Hydroxyl radicals have a very high oxidation potential (eg, 2.8 volts) and have a microsecond level lifetime (eg, lifetime ≤ 2-5 microseconds). The combination of high reactivity and short life allows the uniform surface layer to be oxidized almost instantaneously and then the oxidized surface layer to be removed.

Cobalt is considered an exemplary polycrystalline material that can be etched using the disclosed embodiments.

First, with reference to FIG. 2A, an exemplary embodiment 200 according to the disclosed technique is presented, which is suitable for controlling the etching rate and uniformity as described herein using irradiation with a liquid etching solution. Realizes real-time control. The liquid etching solution 206 is dropped onto the material 204 on the surface of the substrate 208 of the microelectronic workpiece. In the exemplary embodiment 200, the material 204 to be etched is cobalt (Co), which material 204 is already formed on the surface of the substrate 208. In the exemplary embodiment 200, the liquid etching solution 206 provides an oxidative dissolution etching mechanism. In the oxidative dissolution etching mechanism, the material 204 is oxidized by the liquid etching solution 206 and then dissolved by the liquid etching solution 206. In contrast to conventional methods and according to the techniques described herein, irradiation 205 is used to bring the liquid etching solution 206 from a first level reactant with respect to the material 204 on the surface of the substrate 208. , Transition to a second level reactant for material 204. Moreover, the second level of the reactants exceeds the first level of the reactants.

In one embodiment, a liquid etching solution containing hydrogen peroxide (H ₂ O ₂ ) is used. When irradiated with UV light, hydrogen peroxide cleaves to form two hydroxyl radicals (OH ^* ). The formation of this hydroxyl radical raises the oxidation potential of the solution from about 1.8 volts (V) to about 2.8 V. Reactive hydroxyl radicals increase the rate of the oxidation reaction and make the oxidation rate constant k _ox indicated by the arrow 210 much larger than the dissolution rate constant k _d indicated by the arrow 212. This significantly increased rate of oxidation relative to the rate of dissolution (k _ox >> _dd ) facilitates the formation of a thin and uniform layer of oxidized material 214 on the surface of the material at a constant rate. Oxidizing material 214 is then removed to gradually smooth the surface. When cobalt is the material 108, the cobalt oxide (CoO _x ) is the oxidizing material 214.

FIG. 2B shows a representative surface image 250 of this smooth surface due to the increased etching uniformity associated with the irradiation scheme of the disclosed embodiments described herein. In a typical surface image 250, the scale is indicated by bars 252 representing a length of 500 nm.

It is also noted that the rapid formation of the surface oxide layer reduces or minimizes pitting corrosion by preventing etchant diffusion through the grain boundaries and defect sites of the polycrystalline material. From surface morphology analysis, pitting-related corrosion did not occur or was reduced when the irradiation techniques described herein were used. In addition, the surface roughness was significantly reduced from the initial value. Further and / or different advantages are also obtained.

Exemplary treatment modes were also tested using the UV Enhanced Peroxide (UVP) Wet Etching Method described herein for etching polycrystalline materials. In these exemplary treatment modes, polycrystalline cobalt was etched using two exemplary treatment modes to which the UVP wet etching method was applied: continuous UVP treatment and periodic oxidative dissolution treatment.

In the example of continuous UVP treatment, a mixture of hydrogen peroxide (H ₂ O ₂ ) adjusted to pH 10 (pH = 10) and citric acid (eg, in the form of citrate) was used. The oxidation and dissolution reactions in this mode are simultaneous. The results of this process using irradiation are shown in FIG. 2B with respect to the representative image 250. The results of this treatment without irradiation are shown in FIG. 1B (previous technique) with respect to a representative surface image 150.

As mentioned above, FIG. 1A (previous technique) is an exemplary implementation of the oxidation and dissolution reaction rates of cobalt in contact with an aqueous solution of hydrogen peroxide ( _{H2O 2 )} and citrate in the absence of UV irradiation. The form 100 is shown. FIG. 1B (previous technique) corresponds to an exemplary surface image 150 of a post-etched form in a process without UV irradiation, as shown in FIG. 1A (previous technique).

In contrast to the above description, FIG. 2A illustrates an exemplary embodiment ₂₀₀ of the oxidation and dissolution reaction rates of cobalt in contact with aqueous solutions of _H2O2 and citrate in the presence of UV irradiation. show. FIG. 2B corresponds to an exemplary surface image 250 of a post-etched form of processing with UV irradiation, as shown in FIG. 2A. UV irradiation produces transient hydroxyl radicals that allow for higher oxidation rates, resulting in a reduction in surface roughness even at very low etching rates.

In one embodiment, a periodic processing mode is used. In this example of a periodic treatment mode, the oxidation and dissolution reactions are separated. In the first step, cobalt is oxidized by irradiation treatment (eg UVP treatment) in the absence of citrate (eg, lysed and removed) over a given period of time. The layer of oxidizing material (eg, cobalt oxide) is then removed using an aqueous solution of citric acid (eg, in the form of citrate). Cobalt can be uniformly etched by carefully controlling the UVP oxidation and dissolution times.

It should be noted that the complexing agent is not limited to citrate and different complexing agents may be used for this purpose. For example, the complexing agent may include ligands from chemical species such as 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 or iminodiacetic acid. It is further noted that the removal rate depends on the type of complexing agent.

3A-3C show typical results of this periodic processing mode.

FIG. 3A shows a representative surface image 300 of roughness before periodic processing. This figure represents the material on the surface of an untreated substrate. In this example, the material layer has a thickness of 30 nm and an RMS (root mean square) roughness of 1.76 nm.

FIG. 3B shows a representative surface image 350 in a state where the roughness is reduced as compared with FIG. 3A after etching the polycrystalline cobalt using periodic UVP treatment. Since 4 nm was removed by etching, the thickness of the material layer is now 26 nm. The RMS roughness is improved to 0.86 nm, and the decrease in roughness is visible in the surface image. In a typical surface image 350, the scale is indicated by a bar 352 representing a length of 200 nm.

FIG. 3C shows a representative diagram 370 of the AFM (atomic force microscope) surface roughness profile 374/376 before and after the etching process represented by the surface images of FIGS. 3A and 3B. The roughness profile 374/376 shows, for example, the smoothing effect of the etching process after etching 4 nm 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 upper line is the roughness profile 374 representing the surface of the untreated material and bar 378 represents the untreated surface change. The lower line is the roughness profile 376 representing the surface of the material after etching by 4 nm, and the surface changes after etching are represented by bars 380. In the representative figure 370 and the roughness profile 374/376, the scale is indicated by a bar 372 representing a length of 4 nm. As can be seen from the figure, the surface roughness is considerably reduced by the periodic treatment.

For additional embodiments, the etching rate can be controlled over a relatively large surface area of the substrate of the microelectronic workpiece through spatial and / or temporal control of the UV light intensity applied to the liquid etching solution. can. For example, in the case of spatial control, different regions of the liquid etching solution can be irradiated with UV light while the other regions of the liquid etching solution can be left unexposed to UV light. In the case of temporal control, UV light can be applied to different areas of the surface over different lengths of time. By adjusting the spatial and / or temporal irradiation of the surface of the microelectronic workpiece in this way, different etching rates can be obtained.

Various irradiation systems can be used to irradiate the liquid etching solution dropped onto the surface of the substrate of the microelectronic workpiece, including spinner solutions and laser / scanner solutions. When implemented on a spinner, it is possible to optionally synchronize the irradiation light source with the movement of the substrate to illuminate individual areas of the wafer with time-invariant intensity. Spatial decomposition irradiation can be realized, for example, by a light emitting diode (LED) array. LED arrays work well if low spatial resolution is acceptable. The LED array can be rotated in synchronization with the substrate of the spin chamber, or the spatial strength of the array can be synchronized with the movement of the wafer. If higher spatial resolution is desired, irradiation can be performed using a laser source and a scanner. The laser source can move / scan over the wafer surface in motion to provide higher light intensity in areas of the wafer that require higher etching rates. Both of these exemplary implementations can be used to irradiate the wafer at a single wavelength or multiple wavelengths to prepare the reactants in the wet etching solution. It is noted that other light sources may be used. Further, for example, in combination with a light source, an exposure enhanced by accurate laser scanning and overflowing from the zone can be used as an irradiation system. Other variants and implementations can still be realized using the techniques described herein.

4A-B show exemplary embodiments of scanner solutions and laser / scanner solutions for surface irradiation of microelectronic workpieces.

First, referring to FIG. 4A, an exemplary embodiment 400 of a scanner solution is shown in which the LED array 402 is used to irradiate a liquid etching solution dropped onto the surface of a substrate of a microelectronic workpiece such as a semiconductor wafer 404. There is. Prior to irradiation, the liquid etching solution is dispensed onto the surface of the wafer 404 in a spin chamber using a feed system 406. In an exemplary embodiment 400, the LED array 402 may have a single wavelength or may have multiple wavelengths by interspersing different emitters within the array. The output of the individual emitters can be adjusted in real time to control the irradiation intensity over the entire surface of the wafer. In one embodiment, the LED array 402 is mechanically synchronized with the movement of the wafer 404, as indicated by arrows 403, 405. In another embodiment, the intensity of the individual emitters is synchronized with the movement of the wafer 404, whereas the LED array 402 remains stationary. Additional variants may also be implemented.

FIG. 4B shows an exemplary embodiment 450, wherein the irradiation of the liquid etching solution dispensed onto the surface of the substrate of a microelectronic workpiece such as a semiconductor wafer 404 is directed by one or more laser sources 452/456. It is done by. Prior to irradiation, the liquid etching solution is dispensed onto the surface of the wafer 404 in a spin chamber using a feed system 406. A single laser or multiple laser sources 452/456 are then used for irradiation. The plurality of laser sources 452/456 can be used, for example, when it is desirable to irradiate the wafer 404 with a plurality of wavelengths. A steering optical instrument 454/458 is used to scan the wafer surface with a laser beam from a laser source 452/456. The residence time of the laser spot at each point on the surface of the wafer 404 controls the etching enhancement at that point. The movement of the laser beam can be synchronized with the movement of the wafer 404, as indicated by arrows 405, 455 and 459.

In a further additional embodiment, etching uniformity can be improved over a relatively large surface area of the substrate of the microelectronic workpiece by feedforward technology. For example, the topology and / or layer thickness of the surface of the substrate can be measured over the selected surface region and the amount of etching of different regions within this surface region can be determined based on the measured values and the desired result. Can be done. For example, if a smooth surface is desired as a result, the peaks and valleys in the topology may be made uniform by adjusting the local etching rate using spatial and / or temporal control of UV light irradiation. Target surface parameters can be obtained. In this way, feedforward control provides a technique for compensating for non-uniform layer thickness and / or other unevenness over the entire microelectronic workpiece.

FIG. 5A is an exemplary embodiment in which irradiation is used to adjust the reactants in a liquid etching solution to improve etching uniformity when etching a material on the surface of a substrate of a microelectronic workpiece. It is a processing flow diagram of 500. At block 502, the substrate of the microelectronic workpiece is received and the substrate has a material that is etched from the surface of the substrate. At block 504, a liquid etching solution is dropped onto the surface of the substrate and the liquid etching solution has a first level of reactants for the material. Upon irradiation with the liquid etching solution at block 506, the liquid etching solution comes to have a second level of reactants for the material, the second level being above the first level. At block 508, the material is oxidized by the liquid etching solution to form an oxidizing material. At block 510, the oxidizing material is removed. It is noted that additional and / or different steps may still be used while utilizing the irradiation techniques described herein.

FIG. 5B shows the uniformity of etching when etching a polycrystalline metal on the surface of a substrate of a microelectronic workpiece by forming hydroxyl radicals in a liquid etching solution containing hydrogen peroxide using irradiation. It is a processing flow diagram of an exemplary embodiment 550 to be improved. At block 552, the substrate of the microelectronic workpiece is received and the substrate has a polycrystalline metal etched from the surface of the substrate. At block 554, a liquid etching solution containing hydrogen peroxide is dropped onto the surface of the substrate and the liquid etching solution has a first level reactant for the polycrystalline metal. At block 556, irradiation with the liquid etching solution results in the formation of hydroxyl radicals from hydrogen peroxide, and at least in part due to the formation of hydroxyl radicals, the liquid etching solution is a second level reaction with respect to the polycrystalline metal. Have an agent. Moreover, the second level of the reactants exceeds the first level of the reactants. At block 558, the polycrystalline metal is oxidized by the liquid etching solution to form the metal oxide. At block 560, the metal oxide is removed. It is noted that additional and / or different steps may still be used while utilizing the irradiation techniques described herein.

FIG. 6 shows the material on the surface of the substrate of a microelectronic workpiece by adjusting the reactants in an etching solution (eg, a gas etching solution, a liquid etching solution or at least one of a combination thereof) using irradiation. It is a processing flow diagram of an exemplary embodiment 600 which improves the uniformity of etching at the time of etching. At block 602, the substrate of the microelectronic workpiece is received and the substrate has a material that is etched from the surface of the substrate. At block 604, the etching solution is dropped onto the surface of the substrate and the etching solution has a first level of reactants for the material. At block 606, the surface of the etching solution and the material is exposed to irradiation to form a modified layer of the material on the surface of the material, which causes the etching solution to have a second level above the first level for the material. You will have a level of reactants. At block 608, the modified layer of material is removed. It is noted that additional and / or different steps may still be used while utilizing the irradiation techniques described herein.

FIG. 7 is a processing flow diagram of an exemplary embodiment 700 in which a material is polished using irradiation with an etching solution (eg, a gas etching solution, a liquid etching solution, or at least one of a combination thereof). At block 702, the material to be polished is accepted. At block 704, the etching solution is dropped onto the surface of the material and the etching solution has a first level of reactants for the material. In block 706, the surface of the etching solution and the material is exposed to irradiation to form a modified layer of the material on the surface of the material, which causes the etching solution to have a second level above the first level for the material. You will have a level of reactants. At block 708, the modified layer of material is removed and the material has a polished surface. The polished surface is polished to have less surface unevenness than the surface of the original material being etched. It is noted that additional and / or different steps may still be used while utilizing the irradiation techniques described herein.

It is further noted that the techniques described herein can be used in a wide range of processing systems, appliances and platforms. For example, this technique can be used in a wet etching system, as shown in FIG. 8A, which can be used in combination with a dry etching system, as shown in the processing platform embodiment of FIG. 8B. can. Other variants may also be implemented.

FIG. 8A is a block diagram of an exemplary embodiment of the wet etching processing system 800 that can be used with respect to the disclosure technique for etching the material on the surface of the substrate 806. The wet etching processing system 800 includes a wet processing chamber 810. The wet processing chamber 810 can be a pressure control chamber. The substrate 806 (in one example, a semiconductor wafer) is held by a substrate holder 808 such as an electrostatic chuck. The board holder 808 can also be configured to rotate at a controlled speed.

A liquid etching solution supply system 802 and an irradiation system 804 are used together with the wet processing chamber 810. The supply system 802 can include a storage tank for holding the liquid etching solution and a liquid supply pipe in which a discharge nozzle is arranged in the wet processing chamber 810. The supply system 802 can be used to dispense the liquid etching solution onto the surface of the substrate 806. As described herein with respect to FIGS. 4A-4B, the liquid etching solution uses an irradiation system 804 that can be an LED array or other irradiation element that emits light at a single wavelength or multiple wavelengths. Be irradiated. Further, this irradiation may be selective and synchronized with the rotation of the substrate holder 808 and / or otherwise supplied as described herein to irradiate the liquid etching solution with liquid etching. The level of reactants in the solution can be adjusted.

As described herein, the disclosed embodiments provide useful results when used for etching polycrystalline structures such as polycrystalline metallic cobalt. Other polycrystalline materials and metals as well as other materials can also be etched using the irradiation techniques described herein. For example, additional polycrystalline materials and compounds that can be etched include ruthenium, tungsten, titanium, tantalum, titanium nitride, tantalum nitride and / or other materials.

Elements of the wet etching system 800 can be coupled to a corresponding memory storage device and a controller 812 that can be coupled to a user interface (not shown) and then controlled by the controller 812. Various processing operations can be executed via the user interface, and various processing recipes and operations can be stored in the storage device. Therefore, a given substrate 806 can be processed in the wet processing chamber 810 by various techniques. It will be appreciated that the controller 812 can be coupled to various elements of the wet etching system 800 to receive inputs from the elements and provide outputs to the elements.

The controller 812 can be implemented in various ways. For example, the controller 812 can 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 (eg, microprocessors, microcontrollers, central processing units, etc.), programmable logic elements (eg, composite programmable logic elements (CPLD)), field programmable gate arrays (FPGA), etc.) and / Or other programmable integrated circuits can be programmed by software or other programmatic instructions to perform the functions of the legally prohibited plasma processing recipe. Software or other program instructions may be one or more non-temporary computer-readable media (eg, memory storage elements, FLASH memory, DRAM memory, reprogrammable storage elements, hard drives, floppy disks, DVDs, CD-ROMs, etc.). The software or other program instructions can be stored in the programmable integrated circuit and, when executed by the programmable integrated circuit, cause the programmable integrated circuit to perform the processes, functions and / or capabilities described herein. Further attention is paid. Other variants may also be implemented.

FIG. 8B is a block diagram of an exemplary embodiment of the platform 850 that includes a wet etching system 800 and a dry etching system 852. As described herein, the wet etching system 800 dispenses a liquid etching solution into the material to be etched and then irradiates the liquid etching solution to adjust the level of reactants in the liquid etching solution. .. The dry etching system 852 can perform any desired dry etching process that etches or removes material from the substrate being treated. During operation, the dry etching system 852 uses dry etching chemistry to etch the material on the substrate.

The dry etching system 852 includes various dry etching processes such as plasma etching, reactive ion etching (RIE), chemical vapor phase etching (CVE), atomic layer etching (ALE) and / or other dry etching. It is noted that any of the processes can be performed. Further, the dry etching process can be performed before and after the wet etching process. For example, a dry etching process is performed in the dry etching chamber of the dry etching system 852 to remove material from the substrate, resulting in a first surface roughness. The substrate is then transferred (via the transfer module 854) to the wet etching chamber of the wet etching system 800 to perform the wet etching process, resulting in a second surface roughness and a second surface. The roughness is smaller than the first surface roughness. Further, it should be noted that by transferring the substrate using the transfer module 854 as needed, it is possible to perform a plurality of dry etching treatments and a plurality of wet etching treatments. Other variants may also be implemented.

The transfer module 854 and the insulation penetration module 856 may also be coupled between the two systems 800/852 to facilitate the processing of the substrate within the dry etching system 852 and the wet etching system 800. The transfer module 854 is configured to move the substrate between the dry etching system 852 and the wet etching system 800, as indicated by arrow 858. The insulation penetration module 856 is arranged between the transfer module 854 and the wet etching system 800 in order to separate the ambient environment of the transfer module 854 from the ambient environment of the wet etching system 800. The substrate can then be moved between the dry etching system 852 and the wet etching system 800 without exposing the substrate to potential impurities present outside the processing system 800/852. This movement can also be controlled by a controller such as the controller 812 described with respect to FIG. 8A.

Further exemplary embodiments that can be used in the dry etching process system 852, the wet etching process system 800, the transfer module 854 and the insulation penetration module 856 are described in "Patent and Method for Implementing for Integrated End-to" filed January 18, 2019. -US Provisional Patent Application No. 62 / 794,315, entitled "End Gate Contact Process", "Self-Aware and Directing Heaterogeneous Plateform incorporating Engineering Technology Technology" filed January 2, 2019. US Provisional Patent Application No. 62 / 787,607, filed January 2, 2019, "Self-Aware and Directing Heterogeneous Plateform incorporating Integrated Semicondus Application No. 62 / 787,608, US provisional patent application No. 62 / 788,195 and 2019, entitled "Substrate Processing Tool with Integrated Meterology and Method of using" filed January 4, 2019. It is described in US Patent Application Publication No. 16 / 356,451 entitled "PLATFORM AND METHOD OF OPERATING FOR INTER INTEGRATED END-TO-END GATE CONTACT PROCESS" filed March 18th, each of which is described in the US Patent Application Publication No. 16 / 356,451. The whole is incorporated herein by reference.

It is noted that one or more deposition treatments can be used to form the material layers described herein. For example, one or more depositions can be performed using chemical vapor deposition (CVD), plasma CVD (PECVD), physical vapor deposition (PVD), atomic layer deposition (ALD) and / or other deposition processes. .. In the plasma deposition process, a mixture of precursor gases containing, but not limited to, hydrocarbons, fluorocarbons or nitrogens including hydrocarbons is mixed with one or more diluted gases (eg, argon, nitrogen, etc.) and various pressures, powers, flows. And can be used in combination under temperature conditions. Photolithography, extreme ultraviolet (EUV) lithography and / or other lithography processes can be used to perform lithography processes on the photoresist (PR) layer. The etching process can be performed using a plasma etching process, an emission etching process, an atomic layer etching (ALE) and / or other desired etching process. For example, the plasma etching process can be performed using a plasma containing fluorocarbons, oxygen, nitrogen, hydrogen, argon and / or other gases. It is also possible to control the operating variables of the processing step to ensure that the CD (critical dimension) target parameter of the via hole is reached during via hole formation. The operating variables may include, for example, chamber temperature, chamber pressure, gas flow rate, frequency and / or power applied to the electrode assembly during plasma generation and / or other operating variables of the processing step. Modifications may also be implemented while continuing to utilize the techniques described herein.

Throughout the specification, reference to "one embodiment" or "embodiment" is intended to include in at least one embodiment of the invention the particular features, structures, materials or properties described with respect to that embodiment. However, it is noted that they do not mean that they are present in all embodiments. Therefore, the phrase "in one embodiment" or "in an embodiment" that appears in various places throughout the specification does not necessarily refer to the same embodiment of the invention. Moreover, specific features, structures, materials or properties can be combined in any suitable way in one or more embodiments. Various additional layers and / or structures may be included in other embodiments and / or the described features may be omitted.

As used herein, "microelectronic workpiece" generally refers to an object processed in accordance with the present invention. The microelectronic work piece may include any material portion or structure of an element, particularly a semiconductor or other electronic element, and may be a base substrate structure such as a semiconductor substrate or layer covering or on a base substrate structure such as a thin film. .. Thus, the workpiece is not intended to be limited to any particular base structure, underlayer or coating layer, whether patterned or unpatterned, but rather any such layer or base structure. And any combination of layers and / or base structures shall be included. The following description may refer to a particular type of substrate, but this is for illustration purposes only and is not intended to be limiting.

As used herein, the term "subject" means and includes the base material or structure on which the material is formed. It will be appreciated that the substrate may include a single material, multiple layers of different materials, one layer or multiple layers having different materials or regions of different structures internally, and the like. These materials may include semiconductors, insulators, conductors or combinations thereof. For example, the substrate can be a semiconductor substrate, a base semiconductor layer on a support structure, a metal electrode or a semiconductor substrate on which one or more layers, structures or regions are formed. The substrate can be a conventional silicon substrate or other bulk substrate containing a layer of semiconducting material. As used herein, the term "bulk substrate" is used not only for silicon wafers, but also for silicon on insulator ("SOI") substrates, such as silicon on insulator ("SOS"), silicon on glass ("SOG"), and the like. It also means and includes an epitaxial layer of silicon on a base semiconductor foundation and other semiconductors or photoelectronic materials such as silicon germanium, germanium, gallium arsenic, gallium nitride and indium phosphate. The substrate may or may not be doped.

Systems and methods for processing microelectronic workpieces have been described in various embodiments. It will be appreciated by those skilled in the art that various embodiments may be implemented without one or more specific details or with other alternative and / or additional methods, materials or elements. In other examples, known structures, materials or operations are not shown or detailed in order to avoid obscuring aspects of various embodiments of the invention. Similarly, for explanatory purposes, specific numerical values, materials and configurations have been described to provide a good understanding of the invention. However, the invention can be practiced without specific details. Further, it should be understood that the various embodiments shown in the drawings are representations for explanatory purposes and are not necessarily drawn at the same scale.

Further modifications and alternative embodiments of the systems and methods described will be apparent to those of skill in the art from this description. It will therefore be appreciated that the systems and methods described are not limited to these exemplary configurations. It should be understood that the forms of systems and methods presented and described herein should be construed as those given as exemplary embodiments. Various modifications can be made to the implementation. Therefore, although the invention is described herein with respect to a particular embodiment, various improvements and modifications can be made without departing from the scope of the invention. Accordingly, the specification and drawings should be construed in an exemplary and non-limiting sense, and such improvements are included in the scope of the invention. Further, any benefit, advantage or solution to a problem described herein with respect to a particular embodiment shall be construed as an essential, required or essential feature or element of any or all of the claims. Not intended to be.

Claims (22)

A processing system that performs wet etching processing on a substrate.
With a wet treatment chamber configured to perform a wet etching process,
The substrate holder in the wet processing chamber, which is configured to support the substrate,
A supply system arranged to supply a liquid etching solution to the substrate, wherein the liquid solution has a first level reactant with respect to the material on the surface of the substrate.
An irradiation system arranged to irradiate the liquid etching solution such that the etching solution has a second level of reactant different from the first level for the material.
A processing system comprising a controller coupled to the supply system to control the supply of the liquid etching solution and coupled to the irradiation system to control the irradiation output by the irradiation system. The processing system according to claim 1, wherein the controller is configured to control the irradiation system and the supply system so as to periodically etch the material. The treatment system according to claim 1, wherein when the liquid etching solution is irradiated, the surface of the material is oxidized to form an oxidizing material as a modified layer. The treatment system according to claim 3, wherein a uniform layer of the oxidizing material is formed as the modified layer, and the liquid etching solution further dissolves the oxidizing material. The processing system according to claim 4, wherein the liquid etching solution contains an aqueous solution containing hydrogen peroxide and citrate. The processing system according to claim 3, wherein the supply system is further configured to supply an aqueous solution containing a complexing agent for dissolving the oxidizing material. The treatment system according to 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. The processing system according to claim 1, wherein the material to be etched includes a polycrystalline material. The processing system according to claim 8, wherein the polycrystalline material comprises at least one of polycrystalline metal, polycrystalline cobalt, ruthenium, tungsten, titanium, tantalum, titanium nitride or tantalum nitride. The processing system according to claim 1, wherein the irradiation system is configured to selectively irradiate the liquid etching solution. The processing system according to claim 10, wherein the irradiation system is configured to selectively irradiate the liquid etching solution with ultraviolet (UV) light in one or more on / off patterns. The processing system according to claim 10, wherein the irradiation system is configured to selectively irradiate with two or more different colors of light. The controller is configured to control the irradiation system to produce different exposures to different regions of the liquid etching solution to provide different amounts of etching to the material within the different regions. Item 1. The processing system according to Item 1. 13. The processing system of claim 13, wherein the different exposures are based on a measured value of at least one of the surface topology of the material or the thickness of the material. A platform for etching substrates
A dry etching system that etches polycrystalline materials on a substrate by dry etching chemistry,
A wet etching treatment system that etches the polycrystalline material in order to alleviate the roughness of the polycrystalline material generated by the dry etching chemistry.
With a wet treatment chamber configured to perform a wet etching process,
The substrate holder in the wet processing chamber, which is configured to support the substrate,
A supply system arranged to supply a liquid etching solution to the substrate, wherein the liquid solution has a first level reactant with respect to the polycrystalline material.
An irradiation system arranged to irradiate the liquid etching solution such that the etching solution has a second level of reactant different from the first level for the polycrystalline material.
A wet etching processing system comprising a controller coupled to the supply system to control the supply of the liquid etching solution and coupled to the irradiation system to control the irradiation output by the irradiation system.
A transfer module coupled to move the substrate between the dry etching system and the wet etching system.
A platform comprising an insulating penetration module coupled between the transfer module and the wet etching processing tool, the insulating penetrating module that separates the ambient environment of the transfer module from the ambient environment of the wet etching processing system. 15. The platform of claim 15, wherein the controller is configured to control the irradiation system and the supply system to periodically etch the polycrystalline material. 15. The platform of claim 15, wherein the liquid etching solution, when irradiated, oxidizes the surface of the polycrystalline material to form an oxidizing material as a modified layer. 15. The platform of claim 15, wherein the liquid etching solution comprises an aqueous solution containing hydrogen peroxide and the irradiation comprises ultraviolet (UV) light. 15. The platform of claim 15, wherein the dry etching system performs one or more dry etching processes. 19. The one or more dry etching treatments include at least one of plasma etching treatment, reactive ion etching (RIE) treatment, chemical gas phase etching (CVE) treatment or atomic layer etching (ALE) treatment, according to claim 19. Described platform. The dry etching system is configured to etch the polycrystalline material to provide a first surface roughness, and the wet etching chamber has the first surface roughness to be the first surface roughness. The platform according to claim 15, which is configured to adjust to a second surface roughness that is less than the surface roughness. The controller produces different exposures to different regions of the liquid etching solution to etch different amounts of the polycrystalline material based on the surface topology of the material or at least one measurement of the thickness of the material. 21. The platform according to claim 21, which is configured to control the irradiation system to provide.

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