High conformality metal etch in high aspect ratio semiconductor features

Abstract

An exemplary semiconductor processing method may include providing an oxygen-containing precursor to a semiconductor processing chamber at which a substrate may be positioned. The substrate may include a trench formed between two pillars, and a molybdenum-containing metal region in a plurality of recesses formed in at least one of the pillars. At least two of the molybdenum-containing metal regions may be connected by a molybdenum-containing first liner formed on at least a portion of a sidewall of the trench. The method may include forming a plasma of an oxygen-containing precursor. The method may include contacting a molybdenum-containing first liner with a plasma effluent of an oxygen-containing precursor, thereby forming an oxidized portion of molybdenum. The method may include providing a halide precursor. The method may include contacting an oxidized portion of molybdenum with a plasma effluent of a halide precursor, thereby removing the oxidized portion of molybdenum from the sidewalls of the trench.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 17 / 827,356, filed on May 27, 2022, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0002] The present technology relates to semiconductor processes and equipment. More particularly, the present technology relates to laterally etching molybdenum in vertical structures. Background Art

[0003] Integrated circuits are made possible by processes that produce intricately patterned layers of material on a substrate surface. Producing patterned material on a substrate requires a controlled method of removing exposed material. Chemical etching is used for a variety of purposes, including transferring a pattern in a photoresist into an underlying layer, thinning a layer, or thinning the lateral dimensions of a feature already present on a surface. It is often desirable to have an etching process that etches one material faster than another to facilitate, for example, a pattern transfer process. Such an etching process is said to be selective to the first material. Due to the diversity of materials, circuits, and processes, etching processes that are selective to a variety of materials have been developed.

[0004] Depending on the materials used in the process, the etching process can be denoted as wet or dry. Wet HF etching preferentially removes silicon oxide over other dielectrics and materials. However, wet processes may have difficulty penetrating certain confined trenches and may sometimes deform the remaining material. Dry etching produced in a localized plasma formed within the substrate processing area can penetrate more confined trenches and exhibit less deformation of the fine remaining structure. However, the localized plasma may damage the substrate through the generation of arcs when it discharges.

[0005] Therefore, there is a need for improved systems and methods that can be used to produce high quality devices and structures. The present technology can meet these and other needs. Summary of the invention

[0006] An exemplary semiconductor processing method may include providing an oxygen-containing precursor to a semiconductor processing chamber. A substrate may be positioned within the semiconductor processing chamber. The substrate may include a trench and a molybdenum-containing metal region, the trench being formed between pillars, and the molybdenum-containing metal region being in a plurality of recesses formed in at least one of the pillars. At least two of the molybdenum-containing metal regions may be connected by a molybdenum-containing first liner formed on at least a portion of a sidewall of the trench. The method may include forming a plasma of an oxygen-containing precursor in the semiconductor processing chamber. The method may include contacting the molybdenum-containing first liner with a plasma effluent of the oxygen-containing precursor. The contacting may form an oxidized portion of molybdenum on the molybdenum-containing first liner. The method may include providing a halide precursor to the semiconductor processing chamber. The method may include contacting the oxidized portion of molybdenum with a plasma effluent of the halide precursor. The contacting may remove the oxidized portion of molybdenum from the sidewall of the trench.

[0007] In some embodiments, the oxygen-containing precursor may be or may include ozone. The plasma of the oxygen-containing precursor may be formed at a plasma power of less than or about 2000 W. The oxidized portion of the molybdenum may be less than or about The thickness of the molybdenum can be characterized by the thickness of the molybdenum. The halide precursor can be or can include a fluorine-containing precursor. The fluorine-containing precursor can be or can include tungsten hexafluoride. Forming the oxidized portion of the molybdenum can produce a molybdenum oxide layer formed along the sidewalls of the groove. The thickness of the molybdenum oxide layer near the upper region of the groove can differ from the thickness of the molybdenum oxide layer near the lower region of the groove by less than or about 30%. The substrate can further include: a second liner, arranged to be adjacent to the molybdenum-containing metal region and the molybdenum-containing first liner. The method can further include: providing a fluorine-containing precursor to a semiconductor processing chamber, forming a plasma of the fluorine-containing precursor to produce a fluorine-containing plasma effluent, contacting the second liner with the fluorine-containing plasma effluent to form a fluorinated portion of the second liner, providing a chlorine-containing precursor to a semiconductor processing chamber, forming a plasma of the chlorine-containing precursor to produce a chlorine-containing plasma effluent, and contacting the fluorinated portion of the second liner with the chlorine-containing plasma effluent. The contact can remove the fluorinated portion of the second liner. The contacting of the first liner comprising molybdenum with the plasma effluent of the oxygen-containing precursor and the contacting of the oxidized portion of the molybdenum with the plasma effluent of the halide precursor may be repeated at least twice.

[0008] Some embodiments of the present technology may include semiconductor processing methods. The method may include: i) forming a plasma effluent of an oxygen-containing precursor. The method may include: ii) contacting a first molybdenum-containing pad connecting at least two molybdenum-containing metal regions to the plasma effluent of the oxygen-containing precursor, wherein the at least two molybdenum-containing metal regions are arranged in a plurality of grooves defined by at least one column of a trench. The contacting may form an oxidized portion of molybdenum on the first molybdenum-containing pad. The method may include: iii) forming a plasma effluent of a fluorine-containing precursor. The method may include: iv) contacting the oxidized portion of the molybdenum to the plasma effluent of the fluorine-containing precursor. The contacting may remove the oxidized portion of the molybdenum.

[0009] In some embodiments, operations i) to iv) may be repeated at least twice. The oxygen-containing precursor may be or may include ozone. The fluorine-containing precursor may be or may include tungsten hexafluoride. During operations i) and ii), the temperature may be maintained between about 200° C. and about 600° C. During operations i) and ii), the pressure may be maintained at less than or about 20 Torr. The method may include: adjusting the temperature, pressure, or both the temperature and pressure before contacting the oxidized portion of the molybdenum with the plasma effluent of the fluorine-containing precursor. The second pad may be disposed adjacent to the molybdenum-containing metal region and the molybdenum-containing first pad. The method may further include: forming a plasma of a fluorine-containing precursor to produce a fluorine-containing plasma effluent. The fluorine-containing precursor may be or may include nitrogen trifluoride. The method may further include: contacting the second pad with the fluorine-containing plasma effluent to form a fluorinated portion of the second pad, and forming a plasma of a chlorine-containing precursor to produce a chlorine-containing plasma effluent. The chlorine-containing precursor may be or may include boron trichloride. The method may further include: contacting the fluorinated portion of the second liner with a chlorine-containing plasma effluent. The contacting may remove the fluorinated portion of the second liner. The second liner may be or include an oxygen-containing material, a nitrogen-containing material, or an oxygen- and nitrogen-containing material.

[0010] Some embodiments of the present technology cover semiconductor structures. The structure may include a substrate. The structure may include a silicon-containing material covering the substrate. The substrate may include grooves formed between pillars. At least one pillar may define a plurality of grooves. The structure may include: a liner extending along at least one pillar and into the plurality of grooves. The structure may include: a molybdenum-containing metal region formed in the plurality of grooves. The molybdenum-containing metal region may be partially surrounded by the liner. The thickness of the molybdenum-containing metal region in the groove near the upper region of the groove differs by less than or about 30% from the thickness of the molybdenum-containing metal region in the groove near the lower region of the groove.

[0011] In some embodiments, the trench may be characterized by a depth of greater than or about 5 μm. The molybdenum-containing metal region may be surrounded on three sides by a liner. The molybdenum-containing metal region in one recess may be isolated from the molybdenum material in the remaining plurality of recesses.

[0012] Such a technique can provide many benefits relative to conventional systems and techniques. For example, the process can provide uniform top-to-bottom etching of molybdenum-containing metal within the trench. These and other embodiments and their many advantages and features are described in more detail in conjunction with the following description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The nature and advantages of the technology disclosed herein may be further understood by referring to the remainder of the specification and the accompanying drawings.

[0014] Figure 1 A top view of one embodiment of an exemplary processing system in accordance with embodiments of the present technology is shown.

[0015] Figure 2A A schematic cross-sectional view of an exemplary processing chamber in accordance with an embodiment of the present technology is shown.

[0016] Figure 2B An embodiment according to the present technology is shown. Figure 2A A detailed view of a portion of a processing chamber is shown in FIG.

[0017] Figure 3 A bottom view of an exemplary spray head in accordance with an embodiment of the present technology is shown.

[0018] Figure 4 Exemplary operations in a method according to an embodiment of the present technology are shown.

[0019] FIG. 5A to FIG. 5D Shown is a cross-sectional view of a substrate being processed in accordance with an embodiment of the present technology.

[0020] Figure 6 Exemplary operations in a method according to an embodiment of the present technology are shown.

[0021] 7A to 7D Shown is a cross-sectional view of a substrate being processed in accordance with an embodiment of the present technology.

[0022] Several drawings are included in a schematic manner. It should be understood that the drawings are for illustrative purposes only and should not be considered to be to scale unless specifically stated to be to scale. Furthermore, as schematics, the drawings are used to aid understanding and may not include all aspects or information compared to realistic representations and may include exaggerated material for illustrative purposes.

[0023] In the drawings, similar components and / or features may have the same reference numeral. Further, components of the same type may be distinguished by following the reference numeral with a letter that distinguishes between similar components. If only the first reference numeral is used in the specification, the description applies to any of the similar components having the same first reference numeral, regardless of the letter. DETAILED DESCRIPTION

[0024] The growing demands of mobile computing and data centers continue to drive the demand for high-capacity, high-performance NAND flash memory technology. As planar NAND approaches practical scaling limits, 3D NAND is replacing 2D NAND for memory devices. Fabricating 3D NAND structures may require depositing alternating layers of two or more materials. For example, in some structures, alternating layers of silicon oxide and silicon, or alternating layers of silicon oxide and silicon nitride, or alternating layers of silicon oxide and molybdenum, as well as other combinations, may be used, with a total thickness of several microns of stacked layers. These stacked layers may be etched into trenches or contact holes. In addition, one of the two alternating materials, or at least a portion thereof, may be selectively etched from the trenches to form memory cells. For example, silicon, silicon nitride, or molybdenum is the corresponding material that needs to be at least partially removed in the alternating layers of silicon oxide and silicon, silicon oxide and silicon nitride, or silicon oxide and molybdenum. If a liner material is used when forming the stacked layers, such as an aluminum oxide, hafnium oxide, titanium nitride, tantalum nitride, or hafnium nitride liner formed between silicon oxide and molybdenum, the liner may also need to be removed.

[0025] In the transition from 2D NAND to 3D NAND, many process operations (such as etching operations used to form memory cells) are modified from vertical operations to horizontal operations. In addition, as the number of cells to be formed in the 3D NAND structure increases, the aspect ratio of the trenches, contact holes, and other structures will also increase, sometimes significantly. Because of the high aspect ratio of the trenches (>10:1), a common challenge involves etching materials (such as molybdenum and liner materials discussed above) uniformly from top to bottom within the feature. Wet methods are commonly used in these applications, but wet etching may etch the material more than needed or desired. For example, wet etching can significantly etch each layer and can etch almost completely through each layer to other memory holes, which may make it more difficult to place the cell layer in the appropriate or desired position and may weaken the structure and cause deformation. In addition, as the size of the structure continues to decrease, the surface tension of the fluid used in wet etching can cause pattern collapse or bonding problems.

[0026] Conventional plasma dry etching has also been developed for these applications. Because plasma etching can be anisotropic and directional, it can be used to remove material on the top and bottom of the trench, but it may have difficulty uniformly recessing the sidewalls of the memory hole. Plasma dry etching can be combined with wet etching: one etching the top and bottom, and the other etching the sidewalls. However, in such a case, two steps are required, which increases processing time and cost.

[0027] The present technology overcomes these problems by performing a dry etching process that allows for uniform top-to-bottom etching of molybdenum-containing metal and / or liner materials inside high aspect ratio trenches. By oxidizing the molybdenum-containing metal, an oxide layer having a substantially uniform thickness from the top to the bottom of the trench can be formed. By subsequently supplying a halide precursor to selectively etch only the layer oxidized by the previous oxidation operation, uniform etching of the molybdenum-containing metal from top to bottom inside the trench can be achieved. Similarly, by treating the liner material with fluorine, a fluorinated layer having a substantially uniform thickness from top to bottom of the trench can be formed. By subsequently supplying chlorine to selectively etch only the layer oxidized by the previous oxidation operation, uniform etching of the liner material from top to bottom inside the trench can be achieved.

[0028] Although the remainder of the disclosure will routinely identify specific etching processes using the disclosed techniques, it will be readily appreciated that the systems and methods are equally applicable to deposition and cleaning processes that may occur in the chambers described. Therefore, the techniques should not be viewed as limited to techniques used only with these etching processes or chambers. Furthermore, although an exemplary chamber is described as providing a basis for the present techniques, it should be appreciated that the present techniques are applicable to virtually any semiconductor processing chamber that can allow for the described operations.

[0029] Figure 1 A top plan view of one embodiment of a processing system 100 of deposition, etching, baking and hardening chambers according to an embodiment is shown. In the figure, a pair of front opening unification units (FOUPs) 102 supply substrates of various sizes, which are received by a robot 104 and placed into a low pressure holding area 106, which is then placed into one of the substrate processing chambers 108a to 108f, which are positioned in series blocks 109a to 109c. A second robot 110 can be used to transport substrate wafers from the holding area 106 to the substrate processing chambers 108a to 108f and back. Each substrate processing chamber 108a to 108f can be equipped to perform a number of substrate processing operations, including the dry etching process described herein, as well as cyclic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, degassing, orientation, and other substrate processes.

[0030] The substrate processing chambers 108a to 108f may include one or more system components for depositing, annealing, hardening and / or etching dielectric or metal films on substrate wafers. In one configuration, two pairs of processing chambers (e.g., 108c to 108d, and 108e to 108f) in the processing chambers may be used to deposit materials on the substrate, and the third pair of processing chambers (e.g., 108a to 108b) in the processing chambers may be used to etch the deposited materials. In another configuration, all three pairs of chambers (e.g., 108a to 108f) may be configured to etch dielectric or metal films on the substrate. Any one or more of the processes described herein may be performed in (multiple) chambers separate from the manufacturing system as shown in different embodiments. It will be understood that other configurations of chambers for deposition, etching, annealing, and hardening of dielectric films are contemplated.

[0031] Figure 2A A cross-sectional view of an exemplary processing chamber system 200 is shown with separated plasma generation regions within the processing chamber. During film etching (e.g., titanium nitride, tantalum nitride, molybdenum, tungsten, copper, cobalt, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, etc.), process gas may be provided to a first plasma region 215 through a gas inlet assembly 205. A remote plasma system (RPS) 201 may optionally be included in the system and may process a first gas, which then travels through the gas inlet assembly 205. The gas inlet assembly 205 may include two or more different gas supply channels, wherein a second channel (not shown) may bypass the RPS 201, if included.

[0032] A cooling plate 203, a face plate 217, an ion suppressor 223, a showerhead 225, and a pedestal 265 (with a substrate 255 disposed thereon) are shown and may include each of the above depending on the embodiment. The pedestal 265 may have heat exchange channels through which a heat exchange fluid flows to control the temperature of the substrate, which may be operated to heat and / or cool the substrate or wafer during processing operations. Embedded resistive heater elements may also be used to resistively heat the wafer support plate of the pedestal 265 (which may include aluminum, ceramic, or a combination thereof) to achieve relatively high temperatures, such as from up to or about 100° C. to above or about 600° C.

[0033] The faceplate 217 may be pyramidal, conical, or other similar structures, with a narrow top portion expanding to a wide bottom portion. As shown, the faceplate 217 may additionally be flat and include a plurality of through-channels for distributing process gases. Depending on the use of the RPS 201, the plasma generating gas and / or plasma excitation species may be passed through the first plasma region 215 for more uniform delivery to the first plasma region 215. Figure 2B Multiple holes in panel 217 are shown.

[0034] An exemplary configuration may include opening the gas inlet assembly 205 into a gas supply region 258 separated from the first plasma region 215 by a faceplate 217, such that the gas / species flows into the first plasma region 215 through holes in the faceplate 217. Structural and operational features may be selected to prevent significant backflow of plasma from the first plasma region 215 back into the gas supply region 258, the gas inlet assembly 205, and the fluid supply system 210. The faceplate 217 (or the conductive top of the chamber) and the showerhead 225 are shown with an insulating ring 220 located between the features, which allows an AC potential to be applied to the faceplate 217 relative to the showerhead 225 and / or the ion suppressor 223. The insulating ring 220 may be located between the faceplate 217 and the showerhead 225 and / or the ion suppressor 223, so that a capacitively coupled plasma (CCP) can be formed in the first plasma region. A baffle (not shown) may additionally be located in the first plasma region 215, or otherwise coupled to the gas inlet assembly 205, to affect the flow of fluid through the gas inlet assembly 205 into the region.

[0035] The ion suppressor 223 may include a plate or other geometric structure defining a plurality of apertures throughout the structure, the apertures being configured to suppress the migration of ionically charged species away from the first plasma region 215 while allowing uncharged neutral or radical species to pass through the ion suppressor 223 into an activated gas delivery region located between the suppressor and the showerhead. In an embodiment, the ion suppressor 223 may include a perforated plate having a plurality of aperture configurations. These uncharged species may include highly reactive species that are transported through the apertures along with a less reactive carrier gas. As described above, the migration of ionic species through the apertures may be reduced, and in some cases completely suppressed. Controlling the amount of ionic species passing through the ion suppressor 223 may advantageously increase control over the gas mixture in contact with the underlying wafer substrate, which in turn may increase control over the deposition and / or etching characteristics of the gas mixture. For example, adjusting the ion concentration of the gas mixture may significantly change its etching selectivity, e.g., SiNx:SiOx etching ratio, Si:SiOx etching ratio, etc. In performing alternative embodiments of the deposition, it may also shift the balance of conformal-to-flowable style deposition of the dielectric material.

[0036] The plurality of apertures in the ion suppressor 223 can be configured to control the flow of activated gas (i.e., ion species, radical species, and / or neutral species) through the ion suppressor 223. For example, the aspect ratio of the apertures or the diameter to length of the apertures and / or the geometry of the apertures can be controlled to reduce the flow of ionized charged species in the activated gas through the ion suppressor 223. The apertures in the ion suppressor 223 can include a tapered portion facing the plasma excitation region 215 and a cylindrical portion facing the showerhead 225. The shape and size of the cylindrical portion can be set to control the flow of ion species through the showerhead 225. An adjustable electrical bias can also be applied to the ion suppressor 223 as an additional means of controlling the flow of ion species through the suppressor.

[0037] The ion suppressor 223 can function to reduce or eliminate the amount of ionically charged species that travel from the plasma generation region to the substrate. Uncharged neutral and free radical species may still react with the substrate through the openings in the ion suppressor. It should be noted that in embodiments, the ionically charged species in the reaction region surrounding the substrate may not be completely eliminated. In some instances, it is intended that the ion species reach the substrate in order to perform etching and / or deposition processes. In these instances, the ion suppressor can help control the concentration of the ion species in the reaction region to a level that is conducive to the process.

[0038] The showerhead 225 in combination with the ion suppressor 223 can allow the plasma present in the first plasma region 215 to avoid directly exciting the gases in the substrate processing region 233, while still allowing the excited species to travel from the chamber plasma region 215 into the substrate processing region 233. In this way, the chamber can be configured to prevent the plasma from contacting the etched substrate 255. This can advantageously protect the various complex structures and films patterned on the substrate, which may be damaged, misaligned, or warped if directly contacted by the generated plasma. In addition, the rate of etching of oxide species may increase when the plasma is allowed to contact the substrate or close to the level of the substrate. Therefore, if the exposed area of ​​the material is an oxide, the material can be further protected by maintaining the plasma at a remote location from the substrate.

[0039] The processing system may further include a power supply 240 electrically coupled to the processing chamber to provide electrical power to the faceplate 217, the ion suppressor 223, the showerhead 225, and / or the pedestal 265 to generate plasma in the first plasma region 215 or the substrate processing region 233. The power supply may be configured to deliver an adjustable amount of power depending on the process being performed. This configuration may allow an adjustable plasma to be used in the process being performed. Unlike a remote plasma unit that typically has an on or off function, an adjustable plasma may be configured to deliver a specific amount of power to the plasma region 215. This in turn may allow specific plasma characteristics to be developed so that precursors may be dissociated in a specific manner to enhance the etching profile produced by these precursors.

[0040] A plasma may be ignited in the chamber plasma region 215 above the showerhead 225 or in the substrate processing region 233 below the showerhead 225. A plasma may exist in the chamber plasma region 215 to generate radical precursors from, for example, an inflow of a fluorine-containing precursor or other precursor. An AC voltage, typically in the radio frequency (RF) range, may be applied between a conductive top portion of the processing chamber, such as the faceplate 217, and the showerhead 225 and / or the ion suppressor 223 to ignite a plasma in the chamber plasma region 215 during deposition. The RF power supply may generate a high RF frequency of 13.56 MHz, but may also generate other frequencies alone or in combination with the 13.56 MHz frequency.

[0041] Figure 2B A detailed view 253 of features affecting the distribution of process gases through panel 217 is shown. Figure 2A and Figure 2B As shown, the faceplate 217, the cooling plate 203, and the gas inlet assembly 205 intersect to define a gas supply region 258 into which a process gas may be delivered from the gas inlet assembly 205. The gas may fill the gas supply region 258 and flow through the aperture 259 in the faceplate 217 to the first plasma region 215. The aperture 259 may be configured to direct the flow in a substantially unidirectional manner such that the process gas may flow into the substrate processing region 233, but may be partially or completely prevented from flowing back into the gas supply region 258 after passing through the faceplate 217.

[0042] The gas distribution assembly (such as showerhead 225) used in the processing chamber block 200 may be referred to as a dual channel showerhead (DCSH) and is Figure 3The dual channel showerhead may provide for etching processes that allow separation of the etchants outside of the substrate processing region 233 to provide limited interaction with chamber components and each other before being delivered to the processing region.

[0043] The showerhead 225 may include an upper plate 214 and a lower plate 216. The plates may be coupled to each other to define a volume 218 between the plates. The plates may be coupled so as to provide a first fluid channel 219 through the upper and lower plates, and a second fluid channel 221 through the lower plate 216. The channels formed may be configured to provide fluid access from the volume 218 through the lower plate 216 only through the second fluid channel 221, and the first fluid channel 219 may be fluidically isolated from the volume 218 between the plates and the second fluid channel 221. The volume 218 may be fluidly accessed through the side of the showerhead 225.

[0044] Figure 3 FIG. 3 is a bottom view of a showerhead 325 for use with a processing chamber according to an embodiment. The showerhead 325 may correspond to Figure 2A 2. To control and influence the flow of precursors through the showerhead 225, the through-holes 365, which show a view of the first fluid channel 219, can have a variety of shapes and configurations. The small holes 375, which show a view of the second fluid channel 221, can be substantially evenly distributed over the surface of the showerhead, even between the through-holes 365, and can help provide a more even mixing of the precursors as they exit the showerhead than would be possible with other configurations.

[0045] The chambers discussed above can be used to perform exemplary methods, including etching methods. Figure 4 , illustrating exemplary operations in method 400 according to an embodiment of the present technology. Prior to the first operation of method 400, the substrate may be processed in one or more ways. For example, an inter-poly dielectric (IPD) layer may be formed on the substrate. The IPD layer may include any number of materials and may include alternating layers of placeholder material and dielectric material. In an embodiment, the dielectric material may be or may include silicon oxide, and the placeholder material may be or may include silicon nitride. One or more trenches or memory holes may be formed through the stacked IPD layers, and the trenches may divide the IPD layers into vertical pillars for further processing into a 3D NAND structure. For example, a placeholder material layer or at least a portion of the placeholder material layer may be removed to form a lateral groove along the sidewall of the vertical pillar. A gate dielectric may then be used as a liner for the lateral groove, and the lateral groove may be filled with a gate metal to form a gate structure of a 3D NAND. In an embodiment, the gate dielectric may be or may include aluminum oxide, and the gate metal may be or may include molybdenum, tungsten, cobalt, or any other conductive material.

[0046] The gate metal barrier may also be formed between the gate metal and the gate dielectric and / or between the gate metal and the dielectric material of the IPD layer. The gate metal barrier may be or may include a metal, metal oxide, or metal nitride, such as hafnium, titanium, tantalum, aluminum oxide, hafnium oxide, hafnium nitride, titanium nitride, tantalum nitride. Typically, the gate metal may be deposited from top to bottom into the trench and inside the lateral grooves formed along the sidewalls of the trench to form a metal region inserted between the dielectric material layers of the IPD layer. During deposition, the gate metal may also be deposited outside the lateral grooves to line the sidewall portions of the trench and connect the metal regions. Such lining or connecting metal may be removed to separate the metal regions from each other to prevent interference or short circuits between cells. Some or all of the operations may be performed in the aforementioned chamber or system tool, or may be performed in different chambers on the same system tool, which may include one or more chambers in which the operations of method 400 may be performed to remove the connecting metal that lines the sidewalls of the trench.

[0047] Now combine FIG. 5A to FIG. 5D The schematic diagram depicted describes the operations of method 400 . Figure 5A The diagram shows a portion of a processed structure 500 that will be further developed in producing a 3D NAND structure. The processed structure 500 may include one or more trenches 505 (only one is shown) formed between adjacent vertical pillars 510 of a stack of layers covering a substrate 515. The stack of layers may include dielectric layers and metal layers or metal regions interposed between dielectric layers to form gate structures for each memory cell. The dielectric layer may include an oxide layer, such as Figure 5A The metal region may include a molybdenum region, such as Figure 5A . The molybdenum region 525 can be formed by depositing molybdenum in a lateral recess 527 created by removing a layer of placeholder material or a portion thereof. When forming the molybdenum region 525, molybdenum can also be deposited along the top 530, bottom 535 and sidewalls 540 of the trench 505, and two or more molybdenum regions 525 can be connected. The processed structure 500 can further include: one or more barrier materials or liner materials, such as a gate metal barrier and a gate dielectric, which can be referred to together or individually as a second liner. The gate metal barrier can include an oxide, a nitride, or an oxygen and nitrogen barrier, such as Figure 5A The oxide or nitride barrier 545 (e.g., aluminum oxide, hafnium oxide, titanium nitride, tantalum nitride, hafnium nitride, etc.) shown in FIG. The oxide or nitride barrier (also referred to as a second liner) may be disposed adjacent to the molybdenum-containing metal region and / or the molybdenum-containing first liner. The gate dielectric may include an aluminum oxide gate dielectric, such as Figure 5AThe gate dielectric 550 (eg, aluminum oxide) shown in FIG. 5 is a gate dielectric 550. The oxide or nitride barrier 545 may be a metal-containing oxide or nitride material. It is contemplated that the processed structure 500 may include only one of the oxide or nitride barrier 545 and the gate dielectric 550.

[0048] although Figure 5A Only four dielectric material layers and four metal layers are shown, but the processed structure 500 may include any number of layers of each material, such as up to or greater than about 10, greater than or about 15, greater than or about 20, greater than or about 25, greater than or about 30, greater than or about 35, greater than or about 40, greater than or about 45, greater than or about 50, greater than or about 55, greater than or about 60, greater than or about 65, greater than or about 70, greater than or about 80, greater than or about 90, greater than or about 100, or more material layers. This may produce trenches with a width of hundreds of nanometers or tens of nanometers or less, while the height of the trenches may be several micrometers or tens of micrometers or more. The aspect ratio or height to width ratio of the produced trenches may be greater than 20:1, greater than 50:1, greater than 75:1, greater than 100:1, or even greater. In an embodiment, the trenches may be characterized by a width of less than or about 200 nm or less and / or a depth of greater than or about 5 micrometers. As discussed above, the molybdenum-containing material formed on the bottom and / or sidewalls of the trench can be removed to separate the molybdenum regions from each other. Because of the high aspect ratio of the trench, conventional dry etching methods have difficulty achieving uniform etching of the molybdenum metal from the top to the bottom of the trench, also known as a 1:1 top to bottom loading ratio. As will be described in more detail below, the method 400 according to an embodiment of the present technology improves the top to bottom loading and can produce substantially uniform etching of the molybdenum metal within the trench.

[0049] like Figure 5B As shown, method 400 may include initially oxidizing a first molybdenum-containing liner formed on a top 530, a bottom 535, and / or a sidewall 540 of trench 505 to form molybdenum oxide 555 within and on a top of trench 505. In some embodiments, to oxidize molybdenum, substrate 515 may be positioned in a processing region of a semiconductor processing chamber (such as described above with reference to Figure 2AOnce positioned within the processing region, the method 400 may be initiated by providing an oxygen-containing precursor to a remote plasma region of the semiconductor processing chamber at operation 405. The remote plasma region may be fluidly coupled to the processing region, although it may be physically separated to confine the plasma to the substrate level (which may damage exposed structures or materials on the substrate 515). In some embodiments, the remote plasma region may include a remote plasma system (RPS) fluidly coupled to an inlet of the semiconductor processing chamber, such as the RPS 201 discussed above. In some embodiments, the remote plasma region may include a capacitively coupled plasma (CCP) region, such as the first plasma region 215 formed by the capacitive coupling panel 217 and the showerhead 225 and / or the ion suppressor 223, and the CCP region may be physically separated from the processing region by one of its electrodes (such as the showerhead 225 and / or the ion suppressor 223). The method 400 may further include, at operation 410, forming a plasma containing an oxygen precursor to generate an oxygen containing plasma effluent, and at operation 415, providing the oxygen containing plasma effluent to the processing region. At operation 420, the molybdenum connected to the molybdenum region 525 may be oxidized to form molybdenum oxide 555 (e.g., molybdenum oxide 555) on the interior and top of the trench 505. Figure 5B shown).

[0050] The oxygen-containing precursor may include a variety of fluids and may include one or more of the following: atomic oxygen, molecular oxygen (O 2 ), N 2 O, NO, NO 2 , CO 2 、Ozone (O 3 ) or any other oxygen-containing precursor that can similarly perform an oxidation operation. In embodiments, the oxygen-containing precursor can be provided at a rate of at least 1000 sccm, and can be provided at a rate of greater than or about 2000 sccm, greater than or about 3000 sccm, greater than or about 4000 sccm, greater than or about 5000 sccm, greater than or about 6000 sccm, greater than or about 7000 sccm, greater than or about 8000 sccm, greater than or about 9000 sccm, or greater. In some embodiments, the flow of the oxygen-containing precursor can be pulsed. In embodiments, the flow of the oxygen-containing precursor may be pulsed for a time period of less than or about 60 seconds, and may be pulsed for time periods of less than or about 55 seconds, less than or about 50 seconds, less than or about 45 seconds, less than or about 40 seconds, less than or about 35 seconds, less than or about 30 seconds, less than or about 25 seconds, less than or about 20 seconds, less than or about 15 seconds, less than or about 10 seconds, less than or about 5 seconds, or less.

[0051] During the flow of oxygen-containing precursor, the flow rate of oxygen-containing precursor can be maintained at a relatively high level, so that there can be enough or even more than enough oxygen from the top to the bottom of the groove, to completely oxidize the molybdenum connecting the molybdenum region. In some embodiments, sufficient oxygen supply can further improve the uniformity of the thickness of the molybdenum oxide layer formed inside the groove. This uniformity may occur in part due to the initial rapid oxidation that occurs on a pure or clean molybdenum surface. Specifically, method 400 can be performed after molybdenum has been deposited inside the groove but before any atmospheric exposure. The oxidation rate at the pure molybdenum surface can be fast enough, so that in the case of sufficient oxygen supply, the molybdenum near the bottom of the groove can be almost synchronously oxidized to a thickness substantially the same as the thickness of the oxidized molybdenum near the top of the groove. As oxidation penetrates the surface of the metal, the oxidation rate may be significantly reduced, and may reach a saturation depth in some embodiments, and under chamber conditions, minimal oxidation or no further oxidation may continue to occur at the saturation depth. Thus, despite longer residence times at locations near the top of the trench, metal located at locations away from initial contact with the plasma effluent, such as at the bottom of the trench, may be oxidized to a similar or substantially similar depth as at the top of the trench.

[0052] In some embodiments, the initial rapid oxidation may produce a molybdenum oxide layer of a thickness of greater than or about 100 Å before the oxidation process slows down. Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately Greater than or approximately In some embodiments, by adjusting the processing conditions, the initial rapid oxidation can produce a molybdenum oxide layer with a thickness of less than or about Less than or approximately Less than or approximately Less than or approximately Less than or approximately Less than or approximately Less than or approximately or less. In an embodiment, the thickness of the molybdenum oxide layer near the upper region of the trench may differ from the thickness of the molybdenum oxide layer near the lower region of the trench by less than or about 30%, less than or about 25%, less than or about 20%, less than or about 15%, less than or about 10%, less than or about 5%, less than or about 3%, less than or about 1%, or less. Thus, a ratio of less than or about 1.3:1, less than or about 1.25:1, less than or about 1.2:1, less than or about 1.15:1, less than or about 1.1:1, less than or about 1.05:1, or less may be achieved using method 400. Figure 5B In some embodiments, the flow of the oxygen-containing precursor may be maintained for a period of time less than or about 15 minutes, less than or about 10 minutes, less than or about 5 minutes, less than or about 3 minutes, less than or about 2 minutes, less than or about 90 seconds, less than or about 60 seconds, less than or about 50 seconds, less than or about 40 seconds, less than or about 30 seconds, less than or about 25 seconds, less than or about 20 seconds, less than or about 15 seconds, less than or about 10 seconds, less than or about 5 seconds or less. In some embodiments, in order to promote sufficient oxidation, the flow of the oxygen-containing precursor may be maintained for a period of time greater than or about 5 seconds, greater than or about 10 seconds, greater than or about 30 seconds, greater than or about 1 minute, greater than or about 5 minutes, greater than or about 10 minutes, greater than or about 15 minutes or more. Thus, in some embodiments, the flow of the oxygen-containing precursor may be maintained for between about 5 seconds and about 15 minutes, between about 30 seconds and about 10 minutes, between about 1 minute and about 5 minutes, or any other suitable time period.

[0053] The oxygen-containing precursor may also include any number of carrier gases, which may include nitrogen, helium, argon, or other rare, inert, or useful precursors. The carrier gas may be used to enhance uniform distribution of the oxygen-containing precursor within the trench, which may further improve top-to-bottom loading for the oxidation operation 420. In some embodiments, the flow rate of the carrier gas may be maintained at less than or about 50% of the flow rate of the oxygen-containing precursor, or may be less than or about 40%, less than or about 30%, less than or about 20%, less than or about 10%, less than or about 5%, less than or about 3%, or less than or about 1% or less of the flow rate of the oxygen-containing precursor. By adjusting the composition of the components of the oxygen-containing precursor and / or the corresponding flow rate, uniform delivery of the oxygen-containing plasma effluent within the trench may be achieved, thereby further improving the uniformity of molybdenum oxidation from the top to the bottom of the trench.

[0054] Other process conditions may also affect the uniformity of molybdenum oxidation from the top to the bottom of the trench, such as plasma power, operating temperature, operating pressure, etc. In embodiments where the oxygen-containing plasma can be formed in a remote plasma system, the plasma power can be less than or about 2000 W, and can be less than or about 1500 W, less than or about 1000 W, less than or about 750 W, less than or about 500 W, less than or about 250 W, or less to promote the dissociation of the oxygen-containing precursor. In embodiments where the oxygen-containing plasma can be formed in a capacitively coupled plasma (CCP) region of a semiconductor processing chamber, a lower plasma power can be used to avoid damaging structures on the substrate. In embodiments, the plasma power in the CCP region can be at least 50 W, and can be greater than or about 100 W, greater than or about 150 W, greater than or about 200 W, greater than or about 250 W, greater than or about 300 W, greater than or about 350 W, greater than or about 400 W, greater than or about 450 W, greater than or about 500 W, or greater. The plasma power in the CCP region may be less than or about 2500 W, and may be less than or about 2000 W, less than or about 1500 W, less than or about 1000 W, less than or about 750 W, less than or about 500 W, less than or about 250 W, or less.

[0055] In an embodiment, to promote rapid oxidation and thereby improve top-to-bottom loading, the temperature within the processing chamber or at the substrate level may be maintained between about 200° C. and about 600° C. The temperature may be maintained above or about 200° C., and the temperature may be maintained above or about 250° C., above or about 300° C., above or about 350° C., above or about 400° C., above or about 450° C., above or about 500° C., above or about 550° C., above or about 600° C., or more. The higher the temperature that can be maintained during the oxidation operation 420, the faster the molybdenum can be oxidized, and the more uniform the thickness of the molybdenum oxide layer can be. In an embodiment, during the oxidation operation 420, the pressure within the processing chamber may be maintained at less than or about 20 Torr. The pressure may be maintained at less than or about 15 Torr, and the pressure may be maintained at less than or about 10 Torr, less than or about 5 Torr, less than or about 4 Torr, less than or about 3 Torr, less than or about 2 Torr, less than or about 1 Torr, less than or about 100 mTorr, or less. In an embodiment, the pressure may be maintained between about 500 mTorr and about 10 Torr. Maintaining a relatively low pressure inside the processing chamber may promote distribution of oxygen-containing plasma effluent into the trench, resulting in uniform top-to-bottom oxidation as discussed above.

[0056] although Figure 4 The use of an oxygen-containing plasma to oxidize the molybdenum and / or liner material is shown, but a plasma-free process may also be used. Therefore, in some embodiments, operations 410 and 415 of method 400 may be omitted. 2 ), ozone (O3 ) or other oxygen-containing precursors are provided to the processing region to oxidize the molybdenum and / or the liner material. In embodiments where molecular oxygen is used to oxidize the molybdenum and / or the liner material, the temperature within the processing chamber or at the level of the substrate can be maintained between about 250° C. and about 600° C. The temperature can be maintained above or about 250° C., and the temperature can be maintained above or about 300° C., above or about 350° C., above or about 400° C., above or about 450° C., above or about 500° C., above or about 550° C., above or about 600° C., or more. In embodiments where ozone is used to oxidize the molybdenum and / or the liner material, an ozonator can be used to generate ozone, and the ozone generator can be fluidly coupled to the inlet of the processing chamber.

[0057] Given an adequate supply of oxygen-containing precursors and appropriate operating conditions, e.g. Figure 5C As shown, in some embodiments, substantially all of the molybdenum-containing first liner formed on the sidewalls of trench 505 may be oxidized, and a portion of molybdenum region 525 within lateral recess 527 of trench 505 may also be oxidized. While the oxidized molybdenum may be removed in subsequent operations of method 400, slightly etching the molybdenum within lateral recess 527 may ensure separation of molybdenum region 525. Figure 5C As shown in FIG. 4 , during the oxidation operation 420 , when the oxide or nitride barrier 545 includes a nitride, a portion of the oxide or nitride barrier 545 contacting the molybdenum oxide 555 may also be oxidized to form an oxidized portion of the nitride barrier 560 .

[0058] In some embodiments, once the molybdenum-containing first liner formed on at least a portion of the sidewall 540 of the trench 505 is oxidized along with the portion of the molybdenum region 525, the oxidation operation 420 can be paused by stopping the flow of the oxygen-containing precursor. In an embodiment, the residual plasma effluent can be purged before operation 425. At operation 425, a halide precursor can be provided to the processing area. The halide precursor can include a metal halide or other halogen-containing precursor that can react with the molybdenum oxide and / or the liner material. In an embodiment, the halide precursor can be or can include a chlorine-containing precursor or a fluorine-containing precursor. The halide precursor can include tungsten chloride, such as tungsten pentachloride and / or tungsten fluoride, such as tungsten hexafluoride. At operation 430, the halide precursor can be modified and react with the molybdenum oxide 555 to form a volatile substance, which can then be removed from the chamber. The volatile species formed by the halide precursor and the molybdenum oxide 555 may include molybdenum oxychloride and / or molybdenum oxyfluoride. Once the molybdenum oxide 555 is removed by the halide precursor, the underlying oxide or nitride barrier 545 may be exposed, which may also be oxidized as discussed above. Although the exposed portion of the oxide or nitride barrier 545 may be reacted with the halide precursor without prior oxidation, oxidizing the oxide or nitride barrier 545 to form the oxidized portion of the nitride barrier 560 may improve the etch rate.

[0059] The etch rate of the halide precursor on the oxidized portion of the liner material may be at least about 2 times, about 3 times, about 4 times, about 5 times, about 6 times, about 7 times, about 8 times, or more, greater than the etch rate of the halide precursor on the non-oxidized portion of the liner material. The volatile species formed by the halide precursor and the oxidized portion of the nitride barrier 560 may include metal oxychlorides, metal oxyfluorides, metal chlorides (such as metal tetrachlorides), and / or metal fluorides (such as metal tetrafluorides). During operation 425, the halide precursor may be delivered for a time period between about 15 seconds and about 5 minutes. In embodiments, the delivery of the halide precursor may continue for at least about 30 seconds, 1 minute, 1.5 minutes, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, 5 minutes, or more to ensure complete removal of the oxidized portion of the molybdenum oxide 555 and / or the nitride barrier 560. As Figure 5D As shown, the molybdenum oxide 555 and / or the oxidized portion of the nitride barrier 560 may be removed upon completion of the etching operation 430, and the molybdenum regions 525 may be separated from each other.

[0060] At etching operation 430, the oxidized portions of the molybdenum oxide 555 and the nitride barrier 560 may be selectively removed relative to other materials and structures on the substrate, including the molybdenum region 525, the oxide or nitride barrier 545 interposed between the molybdenum region 525 and the gate dielectric 550, and the gate dielectric 550. Without intending to be bound by any particular theory, the gate dielectric 550 may not be etched by the halide precursor in part because the bond between oxygen and the metal in the gate dielectric may be stronger than the bond between oxygen and molybdenum and / or the bond between oxygen and the metal in the gate dielectric, and in part because the reaction products, if any, may include metal fluorides and / or metal oxyfluorides, which may be substantially nonvolatile under the operating conditions of etching operation 430. Although Figure 5D Although not explicitly shown in FIG. 4 , method 400 may also selectively remove oxidized portions of molybdenum oxide 555 and nitride barrier 560 relative to silicon oxide (such as silicon oxide layer 520) and relative to silicon nitride, which may form a charge trap layer for the memory cell.

[0061] Because the halide precursor can selectively etch only the oxidized portion of the molybdenum oxide 555 and / or the nitride barrier 560, and because the oxidation operation 420 can produce a substantially uniform top-to-bottom load as discussed above, the etching operation 430 can also produce a substantially uniform top-to-bottom load. In an embodiment, the etched thickness of the molybdenum layer near the upper region of the trench etched by the method 400 can differ from the etched thickness of the molybdenum layer near the lower region of the trench by less than or about 30%, less than or about 25%, less than or about 20%, less than or about 15%, less than or about 10%, less than or about 5%, less than or about 3%, less than or about 1%, or less. Thus, a top-to-bottom loading of molybdenum etching of less than or about 1.3:1, less than or about 1.25:1, less than or about 1.2:1, less than or about 1.15:1, less than or about 1.1:1, less than or about 1.05:1, or a ratio of substantially or essentially 1:1 may be achieved using method 400. Such uniform top-to-bottom loading may prevent or limit over-etching of molybdenum regions 525 within lateral recesses 527 of trenches 505 while promoting complete removal of molybdenum that may be deposited on sidewalls 540 and / or bottoms 535 of trenches 505 to ensure that molybdenum regions 525 are separated from one another.

[0062] In addition, since the halide precursor can provide isotropic etching, the use of the halide precursor as an etchant can further improve the top-to-bottom loading. Compared to conventional reactive ion etching methods (which can impart directionality and make it difficult to laterally etch the oxidized portion of the molybdenum oxide 555 and / or the nitride barrier 560 lining the sidewall 540 of the trench 505), the halide precursor can react substantially uniformly with the oxidized portion of the molybdenum oxide 555 and / or the nitride barrier 560 within the trench 505, resulting in nearly isotropic etching of the oxidized portion of the molybdenum oxide 555 and / or the nitride barrier 560 within the trench 505. Such uniformity can be promoted by maintaining the pressure within the processing chamber at greater than or about 10 Torr, greater than or about 15 Torr, greater than or about 20 Torr, greater than or about 25 Torr, greater than or about 30 Torr, greater than or about 35 Torr, greater than or about 40 Torr, greater than or about 45 Torr, greater than or about 50 Torr, greater than or about 55 Torr, greater than or about 60 Torr, greater than or about 70 Torr, greater than or about 80 Torr, greater than or about 90 Torr, greater than or about 100 Torr, or more. Higher pressure within the processing chamber can reduce the mean free path of the halide precursor and can achieve non-directional flow of the halide precursor, thereby achieving isotropic etching within the trench. Alternatively, in some embodiments, during the etching operation 430, the pressure within the processing chamber may be maintained at less than or about 100 Torr, less than or about 90 Torr, less than or about 80 Torr, less than or about 70 Torr, less than or about 60 Torr, less than or about 55 Torr, less than or about 50 Torr, less than or about 45 Torr, less than or about 40 Torr, less than or about 35 Torr, less than or about 30 Torr, less than or about 25 Torr, less than or about 20 Torr, less than or about 15 Torr, less than or about 10 Torr, less than or about 5 Torr, less than or about 1 Torr, or less. Thus, in some embodiments, the method 400 may further include: adjusting operating conditions (e.g., temperature, pressure, both temperature and pressure, etc.) within the processing chamber between the oxidation operation and the etching operation. For example, in some embodiments, during oxidation, the pressure may be adjusted from less than or about 5 Torr to a pressure greater than or about 10 Torr. Any of the previously discussed pressures or ranges may be similarly used during both operations.

[0063] As discussed above, a relatively high temperature may be maintained in the processing chamber or at the substrate level during the oxidation operation 420 of the method 400 to promote uniform oxidation. In some embodiments, a relatively low temperature may be maintained in the processing chamber or at the substrate level during the etching operation 430. Due to the high volatility of the byproducts formed using the halide precursor, a higher temperature may not be required to achieve effective etching. In addition, the relatively low temperature may also limit or prevent the surface migration of any non-volatile or less volatile byproducts (such as aluminum fluoride discussed above) that may be formed. During the etching operation 430, the temperature in the processing chamber or at the substrate level during the etching operation 430 may be maintained between about 250°C and about 400°C. In some embodiments, in embodiments, the temperature may be maintained at less than or about 400°C, and may be maintained at less than or about 350°C, less than or about 300°C, less than or about 250°C, or less. In some embodiments, in order to increase the reaction rate, a relatively high temperature may be maintained in the processing chamber or at the substrate level during the etching operation 430. In some embodiments, the temperature maintained within the processing chamber or at substrate level during etching operation 430 may be similar to or even higher than the temperature maintained within the processing chamber or at substrate level during oxidation operation 420. Thus, during etching operation 430, the temperature within the processing chamber or at substrate level may be maintained at greater than or about 400° C., greater than or about 450° C., greater than or about 500° C., greater than or about 550° C., greater than or about 600° C., or even higher.

[0064] There are several ways to maintain different temperatures in the processing chamber or at the substrate level during the oxidation operation 420 and the etching operation 430. When the oxidation operation 420 can be paused, the temperature in the processing chamber or at the substrate level can be reduced or increased to a desired level before the flow of the halide precursor at operation 425 is initiated. Alternatively or additionally, in some embodiments, during the oxidation operation 420, the substrate can be positioned close to a heating source inside the processing chamber to achieve a higher temperature at the substrate level, and after the oxidation operation 420, the substrate can be moved away from the heating source to reduce the temperature at the substrate level for the etching operation 430. For example, in some embodiments, the showerhead 225 can include a heater or can be configured to be heated. During the oxidation operation, the substrate can be positioned close to the showerhead to increase the substrate and operating temperature, and the substrate can be positioned at a first distance from the heating source. After the oxidation operation, the substrate can be moved away from the showerhead to a second distance from the heating source (such as by reducing the susceptor height) to reduce the heating effect. When the substrate is moved, the etching operation can then be performed at a second temperature lower than the first temperature. In some embodiments where the etching operation 430 may be performed at a higher temperature than the oxidation operation 420, the substrate may be positioned farther from a heating source inside the processing chamber so as to achieve a relatively low temperature at the substrate level during the oxidation operation 420, and after the oxidation operation 420, the substrate may be moved closer to the heating source so as to raise the temperature at the substrate level for the etching operation 430.

[0065] In yet other embodiments, the oxidation operation 420, as well as the operation 405 and optional operations 410, 415 for generating the oxygen-containing plasma effluent, may be performed in a chamber separate from the chamber in which the halide precursor is provided at operation 425 to initiate the etching operation 430. Utilizing two chambers maintained at different temperatures for the oxidation operation 420 and the etching operation 430, respectively, may involve additional time to transport the substrate from one chamber to another. However, since temperature adjustment is not required in each chamber and sufficient oxidation can be ensured in one cycle, processing time can be saved, thereby reducing the overall processing time.

[0066] In some embodiments, depending on the thickness of the first molybdenum-containing liner formed on at least a portion of the sidewalls of the trench, method 400 may be performed cyclically to promote complete oxidation and removal of molybdenum outside of the lateral recess to ensure that molybdenum regions are separated from each other. Figure 4 As shown in , method 400 may include repeating oxidation operations 405 to 420 and etching operations 425 to 430. As discussed above, depending on the processing conditions, the initial rapid oxidation of pure or clean molybdenum may produce between about 100 and 200 molybdenum before the oxidation process slows down. About In some embodiments, the method 400 may be performed to form a molybdenum oxide layer of a thickness of about 100 to about 1000 nm or greater. To improve processing efficiency, oxidation of molybdenum may be paused after the initial rapid oxidation, and removal of the oxidized molybdenum may be initiated. After removal of molybdenum, the flow of the oxygen-containing precursor may be resumed to initiate another cycle of method 400. In some embodiments, two or more cycles (such as three cycles, four cycles, five cycles, or more) of oxidation and removal operations may be performed to completely remove the molybdenum-containing first liner formed on at least a portion of the sidewalls of the trench.

[0067] Steering Figure 6 , Figure 6 600 according to an embodiment of the present technology. The operation of the method 600 is also schematically illustrated in 7A to 7D middle, 7A to 7D Graphics and FIG. 5A to FIG. 5D . The method 600 may include operations 605 to 630 similar to operations 405 to 430 of method 400. In some embodiments, the method 600 may include: at operation 605, providing an oxygen-containing precursor to a remote plasma region of a semiconductor processing chamber. As discussed above with reference to method 400, the remote plasma region may be a remote plasma system (RPS) fluidly coupled to a processing region, or may include a capacitively coupled plasma (CCP) region. The method 600 may further include: at operation 610, forming a plasma of the oxygen-containing precursor to produce an oxygen-containing plasma effluent, and at operation 615, providing the oxygen-containing plasma effluent to the processing region. At operation 620, the oxygen-containing plasma effluent may contact and oxidize the molybdenum connected to the molybdenum region 725 to form a capacitively coupled plasma (CCP) region. Figure 7B Molybdenum oxide 755 is shown to be formed inside and on the top of the trench 705. The oxygen-containing precursor may include a variety of fluids and may include one or more of the following: atomic oxygen, molecular oxygen (O 2 ), N 2 O, NO, NO 2 , CO 2 、Ozone (O 3 ) or any other oxygen-containing precursor that can be similarly oxidized.

[0068] although Figure 6 The method 600 may include: using molecular oxygen (O 2 ), ozone (O 3) or other oxygen-containing precursors are provided to the processing region (rather than providing plasma effluents) to oxidize molybdenum. In embodiments where molecular oxygen may be used to oxidize molybdenum, the temperature within the processing chamber or at the substrate level may be maintained between about 250° C. and about 600° C. In embodiments where ozone may be used to oxidize molybdenum, ozone may be generated using an ozone generator, which may be fluidly coupled to an inlet of the processing chamber.

[0069] The residual plasma effluent may be purged prior to operation 625. At operation 625, a halide precursor may be provided to the processing region. The halide precursor may include a metal halide or other halogen-containing precursor that may react with molybdenum oxide. The metal halide may include tungsten chloride (such as tungsten pentachloride) and / or tungsten fluoride (such as tungsten hexafluoride). At operation 630, the halide precursor may be modified and reacted with molybdenum oxide 755 to form a volatile species, which may then be removed from the chamber. The volatile species formed by the halide precursor and molybdenum oxide 755 may include molybdenum oxychloride and / or molybdenum oxyfluoride.

[0070] Method 600 may differ from method 400 in that the operating conditions may be adjusted in method 600 so that the gate metal barrier (such as oxide or nitride barrier 745) may not be oxidized (such as Figure 7B Thus, once the etching operation 630 for etching the molybdenum oxide 755 is completed, the oxide or nitride barrier 745 may not be etched, and as shown Figure 7C As shown, a portion of the oxide or nitride barrier 745 may be exposed. The residual plasma effluent may be purged prior to operation 635. To remove the exposed portion of the oxide or nitride barrier 745, the method 600 may include, at operation 635, providing a fluorine-containing precursor and an optional hydrogen-containing precursor to a remote plasma region of the processing chamber. Again, as discussed above, the remote plasma region may be a remote plasma system (RPS) fluidly coupled to the processing region, or may include a capacitively coupled plasma (CCP) region. The method 600 may further include, at operation 640, forming a plasma of the fluorine-containing precursor and the optional hydrogen-containing precursor to produce fluorine-containing plasma effluents and optional hydrogen-containing plasma effluents, which may be provided to the processing region at operation 645. The plasma effluents of the fluorine-containing precursor and the optional hydrogen-containing precursor may form a fluorinated portion of the oxide or nitride barrier 745.

[0071] The fluorine-containing precursor may include at least one precursor selected from the group consisting of atomic fluorine, diatomic fluorine, nitrogen trifluoride, carbon tetrafluoride, hydrogen fluoride, xenon difluoride, and various other fluorine-containing precursors useful for semiconductor processing or for semiconductor processing. Exemplary fluorine-containing precursors for method 600 may include nitrogen trifluoride. Other fluorine sources may be used in conjunction with nitrogen trifluoride or as a substitute for nitrogen trifluoride. Hydrogen-containing precursors may include diatomic hydrogen, hydrocarbons, water, hydrogen peroxide, or other materials that may include hydrogen. Precursors may also include any number of carrier gases, which may include nitrogen, helium, argon, or other rare, inert, or useful precursors.

[0072] The residual plasma effluent may be cleaned before operation 650. After forming the fluorinated portion of the oxide or nitride barrier 745, the method 600 may include: at operation 650, providing a chlorine-containing precursor to a remote plasma region of the processing chamber. The method 600 may further include: at an optional operation 655, forming a plasma containing a chlorine precursor to produce a chlorine-containing plasma effluent, which may be provided to the processing region at operation 660. In an embodiment, since some chlorine-containing precursors may be used for thermal etching, the method 600 may not include forming a plasma containing a chlorine precursor. The chlorine-containing precursor may include at least one precursor selected from the group consisting of atomic chlorine, diatomic chlorine, boron trichloride, and various other chlorine-containing precursors that may be used for semiconductor processing or are useful for semiconductor processing. An exemplary chlorine-containing precursor for method 600 may include boron trichloride. Other chlorine sources may be used in combination with boron trichloride or as a substitute for boron trichloride. The precursor may also include any number of carrier gases, which may include nitrogen, helium, argon, or other noble, inert, or useful precursors.

[0073] At operation 665, the plasma effluent of the chlorine-containing precursor may react with the fluorinated portion of the oxide or nitride barrier 745 to form volatile byproducts, thereby removing the fluorinated portion of the oxide or nitride barrier 745 (e.g., Fig.7D ). Operation 665 may selectively etch the second liner over the molybdenum and / or molybdenum oxide. A temperature and / or pressure of the processing chamber similar to that utilized in the molybdenum oxidation operation may be maintained to facilitate removal of the exposed portion of the oxide or nitride barrier 745. In other embodiments, the operating temperature and / or pressure during removal of the barrier material may be similar to the operating temperature and / or pressure during removal of the molybdenum oxide.

[0074] In an embodiment, any of the fluorine-containing precursor, the hydrogen-containing precursor, or the chlorine-containing precursor may bypass the remote plasma region and be provided to an additional region of the processing chamber. For example, while a fluorine-containing precursor may be provided through the remote plasma region to produce a fluorine-containing plasma effluent, a hydrogen-containing precursor may bypass the remote plasma region. The hydrogen-containing precursor may bypass the remote plasma region via a bypass at the top of the chamber, or may be provided to a separate region of the chamber, such as by providing a showerhead (such as Figure 2A A hydrogen-containing precursor may then be provided to the processing region, where it may then mix or react with the fluorine-containing plasma effluent.

[0075] In some embodiments, depending on the thickness of the molybdenum-containing first liner and / or the thickness of the oxide or nitride barrier 745 formed on at least a portion of the sidewalls of the trench, method 600 may be performed in cycles to facilitate complete oxidation and removal of the molybdenum and / or oxide or nitride barrier 745 outside the lateral recess to ensure that the molybdenum regions are separated from each other. Figure 6 As shown in FIG. 6 , method 600 may include repeating oxidation operations 605 to 620 and etching operations 625 to 630, and operations 665 to 635. Depending on the processing conditions, the initial rapid oxidation of pure or clean molybdenum may produce between about 100 and 200 Å before the oxidation process slows down. About 1 or greater. To improve process efficiency, oxidation of the molybdenum may be paused after the initial rapid oxidation, and removal of the oxidized molybdenum may begin. After removal of the molybdenum, the flow of the oxygen-containing precursor may be resumed to initiate another cycle of method 600. In some embodiments, two or more cycles (e.g., three cycles, four cycles, five cycles, or more) of oxidation and removal operations may be performed to completely remove the molybdenum-containing first liner formed on at least a portion of the sidewalls of the trench. The same is true for removal of the liner material.

[0076] After operation 665, the molybdenum-containing metal region may be partially surrounded by a liner material, such as surrounded by a liner material on three sides. Further, the molybdenum-containing material in each groove may be isolated from the molybdenum-containing material in the remaining plurality of grooves.

[0077] In the foregoing description, for the purpose of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that certain embodiments may be practiced without some of these details or with additional details.

[0078] After several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the embodiments. In addition, in order to avoid unnecessary confusion of the present technology, several well-known processes and elements are not described. Therefore, the above description should not be considered to limit the scope of the present technology. In addition, the method or process may be described as being performed sequentially or in steps, but it should be understood that the operations may be performed simultaneously or in an order different from the listed order.

[0079] In the case of providing a range of values, unless otherwise expressly specified herein, it should be understood that each intermediate value between the upper and lower limits of this range is also specifically disclosed, with an accuracy of the smallest quantile to the lower limit unit. Any narrower range between any stated value or unstated intermediate value in the stated range and any other stated value or intermediate value in this stated range will be included. The upper and lower limits of these smaller ranges may be independently included in the range or excluded from the range, and any one, no one or both of the limits are included in each range of the smaller range is also covered by the present technology, and each range is limited to any specifically excluded limits in the stated range. In the case where the stated range includes one or both of the limits, the range excluding one or both of those included limits is also included.

[0080] As used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a precursor" includes a plurality of such precursors and reference to "the layer" includes reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth.

[0081] Furthermore, the words “comprise(s),” “comprising,” “contain(s),” “containing,” “include(s),” and “including,” when used in this specification and the following claims, are intended to specify the presence of stated features, integers, components, or operations, but these words do not preclude the presence or addition of one or more other features, integers, components, operations, actions, or groups.

Claims

1. A semiconductor processing method, comprising: An oxygen-containing precursor is provided to a semiconductor processing chamber, wherein a substrate is positioned within the semiconductor processing chamber, wherein the substrate comprises: Grooves formed between the pillars; and a molybdenum-containing metal region located in a plurality of grooves formed in at least one of the pillars, wherein at least two of the molybdenum-containing metal regions are connected by a molybdenum-containing first liner formed on at least a portion of a sidewall of the trench; forming a plasma of the oxygen-containing precursor in the semiconductor processing chamber; contacting the molybdenum-containing first liner with the plasma effluent of the oxygen-containing precursor, wherein the contacting forms an oxidized portion of molybdenum on the molybdenum-containing first liner; providing a halide precursor to the semiconductor processing chamber; and The oxidized portions of molybdenum are contacted with plasma effluents of the halide precursor, wherein the contacting removes the oxidized portions of molybdenum from the sidewalls of the trench.

2. The semiconductor processing method of claim 1, wherein the oxygen-containing precursor comprises ozone.

3. The semiconductor processing method of claim 1, wherein the plasma of the oxygen-containing precursor is formed at a plasma power of less than or about 2000 W.

4. The semiconductor processing method of claim 1, wherein the oxidized portion of molybdenum is less than or about Characterization of thickness.

5. The semiconductor processing method of claim 1, wherein the halide precursor comprises a fluorine-containing precursor.

6. The semiconductor processing method of claim 5, wherein the fluorine-containing precursor comprises tungsten hexafluoride.

7. A semiconductor processing method as described in claim 1, wherein the oxidized portion of the molybdenum is formed to produce a molybdenum oxide layer, the molybdenum oxide layer is formed along the sidewalls of the trench, and wherein the thickness of the molybdenum oxide layer near the upper area of ​​the trench differs from the thickness of the molybdenum oxide layer near the lower area of ​​the trench by less than or about 30%.

8. The semiconductor processing method of claim 1, wherein the substrate further comprises a second liner disposed adjacent to the molybdenum-containing metal region and the molybdenum-containing first liner, the method further comprising: providing a fluorine-containing precursor to the semiconductor processing chamber; forming a plasma of the fluorine-containing precursor to produce a fluorine-containing plasma effluent; exposing the second liner to the fluorine-containing plasma effluent to form a fluorinated portion of the second liner; providing a chlorine-containing precursor to the semiconductor processing chamber; forming a plasma of the chlorine-containing precursor to produce a chlorine-containing plasma effluent; as well as The fluorinated portion of the second liner is contacted with the chlorine-containing plasma effluent, wherein the contacting removes the fluorinated portion of the second liner.

9. The semiconductor processing method of claim 1 wherein the following operations are repeated at least twice: exposing the molybdenum-containing first liner to the plasma effluent of the oxygen-containing precursor and exposing the oxidized portion of the molybdenum to the plasma effluent of the halide precursor.

10. A semiconductor processing method comprising: i) forming a plasma effluent containing an oxygen precursor; ii) contacting a first molybdenum-containing liner connecting at least two molybdenum-containing metal regions disposed within a plurality of recesses defined by at least one pillar of a trench with the plasma effluent of the oxygen-containing precursor, wherein the contacting forms an oxidized portion of molybdenum on the first molybdenum-containing liner; iii) forming a plasma effluent of a fluorine-containing precursor; as well as iv) contacting the oxidized portion of molybdenum with the plasma effluent of the fluorine-containing precursor, wherein the contacting removes the oxidized portion of molybdenum.

11. The semiconductor processing method of claim 10, wherein operations i) to iv) are repeated at least twice.

12. The semiconductor processing method of claim 10, wherein: The oxygen-containing precursor comprises ozone; and The fluorine-containing precursor includes tungsten hexafluoride.

13. The semiconductor processing method of claim 10, wherein during operations i) and ii) the temperature is maintained between about 200°C and about 600°C.

14. The semiconductor processing method of claim 10, wherein during operations i) and ii), the pressure is maintained at less than or about 20 Torr.

15. The semiconductor processing method of claim 10, further comprising: Prior to contacting the oxidized portion of molybdenum with the plasma effluent of the fluorine-containing precursor, temperature, pressure, or both temperature and pressure are adjusted.

16. The semiconductor processing method of claim 10, further comprising: A second liner is disposed adjacent to the molybdenum-containing metal region and the molybdenum-containing first liner, the method further comprising: forming a plasma of a fluorine-containing precursor to produce a fluorine-containing plasma effluent, wherein the fluorine-containing precursor comprises nitrogen trifluoride; exposing the second liner to the fluorine-containing plasma effluent to form a fluorinated portion of the second liner; forming a plasma of a chlorine-containing precursor to produce a chlorine-containing plasma effluent, wherein the chlorine-containing precursor comprises boron trichloride; and The fluorinated portion of the second liner is contacted with the chlorine-containing plasma effluent, wherein the contacting removes the fluorinated portion of the second liner. 17 . The semiconductor processing method of claim 16 , wherein the second liner comprises an oxygen-containing material, a nitrogen-containing material, or an oxygen-and-nitrogen-containing material.

18. A semiconductor structure comprising: substrate; a silicon-containing material covering the substrate, wherein the substrate includes trenches formed between a plurality of pillars, and wherein at least one pillar defines a plurality of recesses; a liner extending along the at least one column and into the plurality of grooves; as well as A molybdenum-containing metal region is formed in the plurality of grooves, wherein the molybdenum-containing metal region is partially surrounded by the liner, and wherein the thickness of the molybdenum-containing metal region in the groove near the upper region of the groove differs from the thickness of the molybdenum-containing metal region in the groove near the lower region of the groove by less than or approximately 30%.

19. The semiconductor structure of claim 18, wherein the trench is characterized by a depth of greater than or about 5 μm.

20. The semiconductor structure of claim 18, wherein: The molybdenum metal-containing region is surrounded on three sides by a gasket; and The molybdenum metal region in one groove is isolated from the molybdenum material in the remaining plurality of grooves.

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