Etching a substrate using ALE and selective deposition

Abstract

The present invention relates to etching substrates using ALE and selective deposition. Methods and apparatuses for processing substrates containing carbonaceous material using atomic layer etching and selective deposition are provided. The methods include exposing a carbonaceous material on a substrate to an oxidizing agent and igniting a first plasma at a first bias power to modify a surface of the substrate, and exposing the modified surface to an inert plasma at a second bias power to remove the modified surface. The methods also involve selectively depositing a second carbonaceous material onto the substrate. The ALE and selective deposition can be performed without breaking vacuum.

Description

[0001] This application is a divisional application of patent application No. 201710291502.8, filed on April 28, 2017, by Rum Research Corporation, entitled "Using ALE and Selective Deposition and Etching of Substrates". Technical Field

[0002] This invention relates generally to the semiconductor field, and more specifically to the use of ALE and selective deposition etching of substrates. Background Technology

[0003] Patterning methods are crucial for semiconductor processing. In particular, extreme ultraviolet (EUV) lithography has been explored to extend lithography beyond its optical limits and replace current lithography methods for patterning small, critical dimension features. Current EUV lithography methods result in poor edge roughness and weak patterning that can ultimately render the substrate useless. Summary of the Invention

[0004] This invention provides methods and apparatus for processing semiconductor substrates. One aspect relates to a method for processing a substrate, the method comprising: (a) exposing a substrate containing a first carbon-containing material to an oxidant and igniting a first plasma at a first bias power to modify the surface of the first carbon-containing material; and (b) exposing the modified surface to a second plasma at a second bias power for a duration sufficient to remove the modified surface without sputtering. In various embodiments, the method further comprises (c) selectively depositing a second carbon-containing material onto the substrate to fill gaps in the first carbon-containing material. In various embodiments, the method further comprises repeating (a)-(c) a plurality of cycles. In various embodiments, the second bias power may be between about 30 V and about 100 V.

[0005] In some embodiments, the oxidant is a strong oxidant. For example, the strong oxidant is oxygen. In some embodiments, the first plasma is generated using a plasma power between about 15 W and about 500 W. The first bias power may be between about 5 V and 50 V.

[0006] In some embodiments, the oxidant is a weak oxidant. For example, the weak oxidant can be any one or more of carbon dioxide, carbon monoxide, sulfur dioxide, nitric oxide, nitrogen, and ammonia. In some embodiments, the first plasma is generated using a plasma power between about 30 W and about 500 W. The first bias power is between about 30 V and about 100 V.

[0007] In various embodiments, selectively depositing the second carbon-containing material onto the substrate includes applying a self-bias at a power between about 5V and about 15V, and igniting the plasma using a plasma power between about 30W and about 500W. In some embodiments, selectively depositing the second carbon-containing material onto the substrate further includes introducing methane. The selective deposition of the second carbon-containing material onto the substrate may also include introducing a diluent such as nitrogen, helium, argon, hydrogen, or combinations thereof.

[0008] In various embodiments, the first carbon-containing material is any one or more of a photoresist, amorphous carbon, and graphene. In some embodiments, the first carbon-containing material is a photoresist patterned by extreme ultraviolet lithography.

[0009] In some embodiments, (c) includes exposing the substrate to methane to adsorb the layered methane onto the surface of the first carbon-containing material and exposing the substrate to a third plasma.

[0010] The third plasma can be generated by introducing an inert gas such as helium, hydrogen, nitrogen, argon, and neon and igniting the plasma.

[0011] In various embodiments, exposing the substrate containing the first carbon-containing material to the oxidant further includes exposing the substrate to a diluting inert gas, such as any one or more of helium, argon, neon, krypton, and xenon.

[0012] The second plasma in (b) can be generated by introducing an inert gas such as hydrogen, helium, nitrogen, argon and neon and igniting the plasma.

[0013] In various embodiments, the method further includes purging the chamber containing the substrate between execution (a) and execution (b) to remove excess oxidant from the chamber.

[0014] In some implementations, the method further includes repeating (a) and (b) multiple loops.

[0015] The substrate can be placed on a base at a temperature between about 0°C and about 120°C.

[0016] On the other hand, an apparatus for processing a substrate is provided, the apparatus comprising: one or more processing chambers, each processing chamber including a chuck; one or more gas inlets leading to the processing chambers and associated flow control hardware; and a controller having a memory and at least one processor, such that the at least one processor and the memory are communicatively connected to each other, the at least one processor being operatively connected to at least the flow control hardware, and the memory storing computer-executable instructions for controlling the at least one processor to control the flow control hardware by at least the following steps: (i) introducing an oxidant into the processing chamber and igniting a first plasma with a first bias power; and (ii) introducing a first inert gas and igniting a second plasma with a second bias power, such that (i) and (ii) are performed without breaking the vacuum.

[0017] In various embodiments, the memory further includes instructions for: (iii) introducing a carbon-containing precursor into the processing chamber to form an adsorbed layer of the carbon-containing precursor adsorbed onto the surface of a substrate contained in one or more processing chambers; and (iv) introducing a second inert gas and igniting a third plasma.

[0018] In various embodiments, the instructions also include instructions for switching on self-bias at a power between about 5V and about 15V when the carbon-containing precursor is introduced in (iii).

[0019] In various embodiments, the instructions also include instructions for introducing a diluent selected from nitrogen, helium, argon, hydrogen, and combinations thereof.

[0020] In various embodiments, the oxidant is oxygen. The first bias power may be between about 5V and about 50V. In various embodiments, the first plasma is set to a plasma power between about 15W and 500W.

[0021] In various embodiments, the oxidant is any one or more of carbon dioxide, carbon monoxide, sulfur dioxide, nitric oxide, nitrogen, and ammonia. In some embodiments, the first bias power is between about 30V and about 100V. In some embodiments, the first plasma is set to a plasma power between about 30W and 500W.

[0022] Specifically, some aspects of the present invention can be described as follows:

[0023] 1. A method for processing a substrate, the method comprising:

[0024] (a) exposing a substrate containing a first carbon-containing material to an oxidant and igniting a first plasma with a first bias power to modify the surface of the first carbon-containing material; and

[0025] (b) Exposing the modified layer to a second plasma at a second bias power for a duration sufficient to remove the modified surface without sputtering.

[0026] 2. The method according to Clause 1, further comprising (c) selectively depositing a second carbon-containing material on the substrate to fill gaps in the first carbon-containing material.

[0027] 3. The method according to Clause 1, wherein the second bias power is capable of being between about 30V and about 100V.

[0028] 4. The method according to Clause 1, wherein the oxidizing agent is a strong oxidizing agent.

[0029] 5. The method according to Clause 4, wherein the strong oxidizing agent is oxygen.

[0030] 6. The method according to Clause 4, wherein the first plasma is generated using a plasma power between about 15 W and about 500 W.

[0031] 7. The method according to Clause 4, wherein the first bias power is between approximately 5V and 50V.

[0032] 8. The method according to Clause 1, wherein the oxidizing agent is a weak oxidizing agent.

[0033] 9. The method according to Clause 8, wherein the weak oxidizing agent is selected from carbon dioxide, carbon monoxide, sulfur dioxide, nitric oxide, nitrogen, and ammonia.

[0034] 10. The method according to Clause 8, wherein the first plasma is generated using a plasma power between about 30 W and about 500 W.

[0035] 11. The method according to Clause 8, wherein the first bias power is between about 30V and about 100V.

[0036] 12. The method according to Clause 2, wherein selectively depositing the second carbon-containing material on the substrate comprises applying a self-bias at a power between about 5V and about 15V, and igniting the plasma using a plasma power between about 30W and about 500W.

[0037] 13. The method according to Clause 12, wherein selectively depositing the second carbon-containing material on the substrate further comprises introducing methane.

[0038] 14. The method according to Clause 13, wherein selectively depositing the second carbon-containing material on the substrate further comprises introducing a diluent selected from nitrogen, helium, argon, hydrogen, and combinations thereof.

[0039] 15. The method according to any one of clauses 1-14, wherein the first carbon-containing material is selected from photoresist, amorphous carbon, and graphene.

[0040] 16. The method according to any one of Clauses 1-14, wherein the first carbon-containing material is a photoresist patterned by extreme ultraviolet lithography.

[0041] 17. The method according to Clause 2, wherein (c) comprises exposing the substrate to methane to adsorb the layered methane onto the surface of the first carbon-containing material and exposing the substrate to a third plasma.

[0042] 18. The method according to Clause 17, wherein the third plasma is generated by introducing an inert gas selected from helium, hydrogen, nitrogen, argon and neon and igniting the plasma.

[0043] 19. The method according to any one of clauses 1-14, wherein exposing the substrate comprising the first carbon-containing material to the oxidant further comprises exposing the substrate to a diluting inert gas selected from helium, argon, neon, krypton, and xenon.

[0044] 20. The method according to any one of clauses 1-14, wherein the second plasma in (b) is generated by introducing an inert gas selected from hydrogen, helium, nitrogen, argon and neon and igniting the plasma.

[0045] 21. The method according to any one of clauses 1-14, further comprising purging the chamber containing the substrate between execution (a) and execution (b) to remove excess oxidant from the chamber.

[0046] 22. The method according to any one of clauses 1-14 further includes cyclic repetition of (a) and (b).

[0047] 23. The method described in Clause 2 further includes repeating (a)-(c) cyclically.

[0048] 24. The method according to any one of clauses 1-14, wherein the substrate is housed on a base disposed at a temperature between about 0°C and about 120°C.

[0049] 25. An apparatus for processing a substrate, the apparatus comprising:

[0050] (a) One or more processing chambers, each processing chamber including a chuck;

[0051] (b) One or more gas inlets leading to the processing chamber and associated flow control hardware; and

[0052] (c) A controller having at least one processor and a memory, wherein the at least one processor and the memory are communicatively connected to each other.

[0053] The at least one processor is operatively connected to the flow control hardware at least once, and

[0054] The memory stores computer-executable instructions for controlling the at least one processor to control the flow control hardware through at least the following steps:

[0055] (i) Introducing an oxidant into the processing chamber and igniting a first plasma with a first bias power; and

[0056] (ii) Introduce a first inert gas and ignite the second plasma with a second bias power.

[0057] (i) and (ii) are performed without breaking the vacuum.

[0058] 26. The apparatus according to Clause 25, wherein the memory further comprises instructions for: (iii) introducing a carbon-containing precursor into the processing chamber to form an adsorbed layer of the carbon-containing precursor adsorbed onto the surface of a substrate contained in one or more of the processing chambers; and (iv) introducing a second inert gas and igniting a third plasma.

[0059] 27. The apparatus according to Clause 26, wherein the instructions further include instructions for switching on self-bias at a power between about 5V and about 15V when the carbon-containing precursor is introduced in (iii).

[0060] 28. The apparatus according to Clause 26, wherein the instructions further include instructions for introducing a diluent selected from nitrogen, helium, argon, hydrogen, and combinations thereof.

[0061] 29. The apparatus according to any one of clauses 25-28, wherein the oxidant is oxygen.

[0062] 30. The device according to Clause 29, wherein the first bias power is between about 5V and about 50V.

[0063] 31. The apparatus according to Clause 29, wherein the first plasma is configured with a plasma power between about 15 W and 500 W.

[0064] 32. The apparatus according to any one of clauses 25-28, wherein the oxidant is selected from carbon dioxide, carbon monoxide, sulfur dioxide, nitric oxide, nitrogen, and ammonia.

[0065] 33. The device according to Clause 32, wherein the first bias power is between about 30V and about 100V.

[0066] 34. The apparatus according to Clause 32, wherein the first plasma is configured with a plasma power between about 30 W and 500 W.

[0067] These and other aspects are further described below with reference to the accompanying drawings. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of an example of atomic layer etching on a substrate.

[0069] Figure 2 This is a schematic diagram of an example of atomic layer etching on a resist with protrusions.

[0070] Figure 3 This is a schematic diagram illustrating an example of a removal operation during atomic layer etching.

[0071] Figure 4 This is a schematic diagram of a selective deposition cycle that can be used according to certain disclosed embodiments.

[0072] Figure 5 It is a flowchart of the operations performed according to the disclosed implementation method.

[0073] Figure 6 This is a schematic diagram of an exemplary processing chamber for performing certain disclosed embodiments.

[0074] Figure 7 This is a schematic diagram of an exemplary processing apparatus for performing certain disclosed embodiments.

[0075] Figure 8A This is an image of the substrate used in the experiment.

[0076] Figure 8B This is an image of the substrate from the experiment.

[0077] Figure 8C-8E These are images of substrates obtained from experiments conducted according to certain disclosed embodiments.

[0078] Figures 9A-9C These are various views of the substrate.

[0079] Figures 10A-10C 11A-11C are various views of the substrate from experiments conducted according to certain disclosed embodiments. Detailed Implementation

[0080] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well-known processing operations have not been described in detail to avoid unnecessarily obscuring the disclosed embodiments. Although the disclosed embodiments are described in conjunction with specific embodiments, it should be understood that this is not intended to limit the disclosed embodiments.

[0081] Thin-film patterning in semiconductor processing is used in the fabrication and preparation of semiconductor devices. Conventional patterning involves photolithography, such as 193nm photolithography. In photolithography, a pattern is printed by emitting photons from a photon source onto a mask and then onto a photosensitive photoresist, thereby inducing a chemical reaction in the photoresist, which removes portions of the photoresist to form the pattern. As devices shrink, the need to print smaller features increases. While various patterning techniques have been developed for use with conventional photolithography, multi-layer patterning uses multi-layer deposition and etching processes. The scaling of features in advanced semiconductor integrated circuits (ICs) and other devices has driven photolithography techniques to improve resolution by moving to smaller imaging source wavelengths.

[0082] Extreme ultraviolet (EUV) lithography has been developed to print smaller patterns on photoresist using EUV light sources with wavelengths of approximately 13.5 nm in advanced lithography tools (also known as scanners). While next-generation EUV was first anticipated in 2006 to support 45 nm technology node manufacturing, this development has been long delayed due to several productivity issues. One challenge to EUV productivity has been generating sufficient power to perform patterning due to the inherent difficulty in creating and focusing 13.5 nm photons. System throughput, and therefore overall cost and productivity, are determined by the ratio of photons delivered on the wafer to the photons required to image the photoresist. Although methods designed to modify the source have been developed over the past decade, methods have not yet been used at the 45 nm technology node to achieve a source power of 250 W that enables efficient use of EUV technology. The source power required to perform EUV increases with device shrinkage due to shot noise and resist blurring, making a 500 W–1000 W source power cost-competitive with existing patterning techniques for EUV performance at the 5 nm technology node.

[0083] (Especially for through-hole imaging) Insufficient source power leads to a loss of pattern fidelity in both the edge roughness of the patterned image and the defined critical dimensions. This is due, among other reasons, to the limited number of photons available for each through-hole image, and the random variation in the number of photons in each feature and the efficiency of each photon in generating photoacid, resulting in random variations in aperture size (also known as local critical dimension uniformity, or “LCDU” in this paper) and edge roughness (also known as line edge roughness, or “LER” in this paper).

[0084] Existing techniques for patterning photoresists for small, critical-size devices include reactive ion etching (“RIE”) processes that harden, smooth, and remove residues from the photoresist. However, current RIE processes cannot address LER or LCDU. For example, photoresists treated with RIE may still contain small wrinkles between features. And the corrosion-resistant scum on the bottom of the feature.

[0085] This paper provides a method for etching a substrate (such as a photoresist) to produce uniformly etched and smooth edges in imaging features after photolithography. Such a technique, as described herein, improves upon LER and LCDU. The disclosed embodiments reduce the need for high source power to perform EUV applications, thereby increasing the productivity of EUV scanners. The disclosed embodiments are suitable for etching substrates to form structures such as contacts that interact with source / drain regions, 3-D contact holes, etc.

[0086] The method involves atomic layer etching (ALE) and selective deposition to gently etch and smooth materials such as carbon-containing materials. Exemplary carbon-containing materials that can be etched using the disclosed embodiments include photoresists (such as those used in EUV or immersion etching) and amorphous carbon.

[0087] Atomic layer etching (ALE) is a technique that removes thin layers of material using a sequential, self-limiting reaction. Generally, any suitable technique can be used to perform ALE. Examples of atomic layer etching techniques are described in U.S. Patent No. 8,883,028, published November 11, 2014; U.S. Patent No. 8,808,561, published August 19, 2014; and U.S. Patent No. 9,576,811, published February 21, 2017, which are incorporated herein by reference for the purpose of describing exemplary atomic layer etching and etching techniques. In several embodiments, ALE can be performed using plasma or thermal methods.

[0088] ALE can be cyclical. The concept of an “ALE cycle” relates to the discussion of several embodiments herein. Typically, an ALE cycle is a minimal set of operations for performing a single etching process (e.g., etching a single layer). The result of a cycle is the etching of at least some film layers onto the substrate surface. Typically, an ALE cycle includes a modification operation that forms a reactive layer, followed by a removal operation that removes or etches only this modified layer. The cycle may include certain auxiliary operations, such as scavenging one of the reactants or byproducts. Typically, a cycle includes one example of a unique series of operations. For example, an ALE cycle may include the following operations: (i) delivering reactant gas (adsorption), (ii) purging reactant gas from the chamber, (iii) delivering a remover gas and optionally plasma (desorption), and (iv) purging the chamber.

[0089] Figure 1 Two exemplary schematic diagrams of the ALE cycle and a schematic diagram of selective polymer deposition are shown. Figure 1 Figures 171a-171e illustrate an exemplary ALE cycle. In 171a, a substrate is provided.

[0090] In various embodiments, the substrate may be a silicon wafer, such as a 200 mm, 300 mm, or 450 mm wafer, including wafers having one or more material layers, such as dielectric, conductive, or semiconductor materials deposited thereon. In some embodiments, the substrate includes a capping layer of silicon (e.g., amorphous silicon) or germanium. The substrate may include a patterned mask layer pre-deposited and patterned on the substrate. For example, the mask layer may be deposited and patterned on a substrate including an amorphous silicon capping layer. In some embodiments, the substrate surface includes a photoresist, graphene, or amorphous carbon.

[0091] In some embodiments, the layers on the substrate may be patterned. The substrate may have “features,” such as vias or contact holes, which may be characterized as one or more narrow and / or re-entrant openings, feature contractions, and high aspect ratios. These features may be formed in one or more of the aforementioned layers. One example of a feature is a hole or via in a semiconductor substrate or a layer on that substrate. Another example is a trench defined by a line or space in the substrate or layer. In many embodiments, the feature may have an underlying layer, such as a barrier layer or adhesive layer. Non-limiting embodiments of the underlying layer include dielectric and conductive layers, such as silicon oxide, silicon nitride, silicon carbide, metal oxide, metal nitride, metal carbide, and metal layers. In some embodiments, the surface of the substrate may include more than one type of material, for example, if the substrate is patterned. The substrate includes at least one material to be etched and smoothed using the disclosed embodiments. This material may be any of the aforementioned metals, dielectrics, semiconductor materials, etc. In various embodiments, these materials may be prepared for the fabrication of contacts, vias, gates, etc. In some implementations, the material to be etched is a hard mask material, such as amorphous carbon. Other exemplary materials include aluminum gallium nitride, silicon, gallium nitride, tungsten, and cobalt.

[0092] In step 171b, the surface of the substrate is modified. In step 171c, the modified layer is retained after a cleaning operation to remove excess non-adsorbed precursors. In step 171d, the modified layer is etched. In step 171e, the modified layer is removed.

[0093] Similarly, Figure 1 Examples of ALE cycles for etching carbon-containing films are shown in 172a-172e. In 172a, a substrate comprising a carbon-containing material containing a plurality of carbon atoms is provided. In various embodiments, the substrate includes a carbon-containing layer, such as a photoresist or an amorphous carbon layer.

[0094] In 172b, an oxidant is introduced into the substrate, which modifies the surface of the substrate. The oxidant can be a strong oxidant, such as oxygen (O2), or a weak oxidant, such as carbon dioxide (CO2). The choice of oxidant may depend on the type of carbon-containing material on the substrate. For example, in some embodiments, the strong oxidant may be an oxidant suitable for etching hard carbon-containing materials (such as amorphous carbon or graphene). In another example, in some embodiments, the weak oxidant may be an oxidant suitable for etching photoresists patterned by EUV (extreme ultraviolet) lithography or immersion lithography.

[0095] For example, a schematic diagram in 172b illustrates the adsorption of oxidants onto the surface of a substrate. The modification operation forms a thin, reactive surface layer that is more easily removed in subsequent removal operations than the unmodified material. To etch carbonaceous materials, oxygen-containing plasma can be used during the modification or adsorption operation. Oxygen-containing plasma can be generated by flowing an oxygen-containing modifying chemical (e.g., oxygen (O2)) or a weak oxidant (e.g., carbon dioxide (CO2)) and igniting the plasma. Other weak oxidants include carbon monoxide (CO), nitrogen oxides (NO), and sulfur dioxide (SO2). Additional reactants can include nitrogen, hydrogen, and ammonia compounds, as well as substances that can reactively bind to the resist surface and subsequently volatilize using sub-sputtering threshold ion bombardment. These strong and weak oxidants can be used alone or in combination, including with diluted inert gases such as helium (He), argon (Ar), neon (Ne), krypton (Kr), xenon (Xe), and combinations thereof. This operation modifies a carbonaceous material surface several angstroms thick to form a modified layer with weaker bond energies than the host carbonaceous material. In various embodiments, a weak oxidant is provided to the substrate as an unbiased or low-biased plasma. For example, in various embodiments, the weak oxidant is introduced into a plasma processing chamber, and the plasma source power is turned on to ignite the plasma, thereby promoting the adsorption of the weak oxidant onto the surface of the carbon-containing material. The bias voltage can be applied at a low power or voltage (e.g., a self-biased voltage between about 5V and about 15V or up to about 50V). The plasma power can be set between about 15W and about 300W. It should be understood that the terms “bias power” and “bias voltage” are used interchangeably herein to describe the voltage at which the substrate is set when a bias is applied to it. The bias power or bias voltage described herein is measured in volts, which are expressed in units “V” or “Vb”, where b refers to the bias.

[0096] In step 172c, a weak oxidizing agent is purged from the chamber. In step 172d, a removal gas, argon, containing directional plasma, is introduced. + The plasma material and arrows indicate that ion bombardment is used to remove the modified carbon surface of the substrate. During this operation, a bias is applied to the substrate to attract ions toward it. In the desorption operation, an inert gas plasma (e.g., He, Ar, Xe, or N2) can be used to remove the modified layer. Although argon is depicted in 172d, it should be understood that any suitable inert gas can be used to generate the plasma for this operation. In various embodiments, the bias power applied during removal can be between about 30 V and about 100 V. The bias power can be selected such that the energy supplied to the substrate is less than the energy required to sputter the substrate, but greater than the energy used to remove the modified layer from the substrate. The plasma power can be set between about 30 W and about 500 W.

[0097] In 172e, the cleaning chamber is used to remove byproducts. In various embodiments, approximately [amount missing] can be removed in one cycle. Peace Treaty Materials in between. If a stronger oxidant is used, the etching rate may be greater than that with a weaker oxidant. For example, for a strong oxidant such as oxygen (O2), the inert plasma gas can be Ar, and about 10 to about 30 angstroms of resist material can be removed. In some embodiments, if the weak oxidant used is carbon dioxide and the inert gas plasma used to remove the modified layer is helium, then each cycle can etch material between about 2 and 3 angstroms. The post-etched surface of carbon-containing materials is typically smooth after ALE treatment. For example, in some embodiments, the root mean square roughness of the surface after ALE treatment can be less than about 0.5 nm (Rrms < 0.5 nm).

[0098] Figure 2 This illustrates how this operation can reduce the presence of protrusions on the photoresist. The size of the protrusions on the photoresist can be between about 1 angstrom and about 30 angstroms in diameter and / or height. An exemplary substrate 200 with photoresist material and protrusions 299 is provided. A weak oxidant 201 is provided and adsorbed onto the substrate 200, which modifies the surface of the substrate 200 to form a modified surface 202. The modified surface 202 is then removed; dashed line 203 shows the location of the previous carbon-containing material on the substrate 200, where the substrate 210 now exists. This process 250 can constitute an ALE oxidation cycle. Process 260 shows a substrate 220 with protrusions 298 exposed to a weak oxidant 221. The weak oxidant 221 is adsorbed onto the substrate 220, which modifies the surface of the substrate 220 to form a modified surface 222. A weak oxidant 231 is adsorbed onto a substrate 230 to form a modified layer (not shown), and the modified layer is further removed to produce a substrate 270, which includes a dashed line 275, indicating the location of the previously carbon-containing material on the substrate 230.

[0099] Unbound by any particular theory, it is believed that the scale of the protrusions is at the atomic level, such that, due to the larger surface-to-volume ratio of the protrusions, when carbonaceous material is adsorbed onto the surface of the protrusions and a single or double layer of protrusions is removed, the size of the protrusions is significantly reduced relative to the material removed from adjacent, relatively flat portions of the surface. This is likely because more carbonaceous material is adsorbed onto the larger surface area provided by the protrusions.

[0100] Figure 3This illustrates how the removal operation can improve the smoothing of the material being etched. An inert plasma material is used in 172d with a low bias, giving the plasma material sufficient energy to remove the weakly oxide-modified surface of carbon atoms adsorbed onto the substrate surface, but not enough energy to sputter away the underlying unmodified carbon atoms from the substrate surface. In various embodiments, the bias can be between about 30V and about 100V, or less than about 50V. In some embodiments, the modified layer can be about 0.5 nm thick, and may comprise about 3 to 4 atomic layers. In some embodiments, such as... Figure 3 As shown, a phase boundary can exist between the modified layer and the amorphous material. Figure 3 The inert plasma material (e.g., Ar+) shown can be a subthreshold, non-reactive ionic material, where subthreshold means the energy of the inert plasma material is insufficient to sputter the material beneath the modified layer, but high enough to remove the modified layer. Threshold bias power, or threshold bias voltage, refers to the maximum bias voltage applied to the substrate surface before the material on the substrate surface is sputtered. Therefore, the threshold bias power depends in part on the material to be etched, the gas used to generate the plasma, the plasma power used to ignite the plasma, and the plasma frequency. After each cycle, the surface can be "reset" such that the surface contains the material to be removed, with little or no modified material remaining on the surface.

[0101] Further descriptions of substrate smoothing using ALE technology are found in U.S. Provisional Patent Application No. 62 / 214,813, filed September 4, 2015, entitled “ALE SMOOTHNESS: IN AND OUTSIDE SEMICONDUCTOR INDUSTRY,” and in U.S. Patent Application Publication No. 2017 / 0069462, filed August 31, 2016, entitled “ALESMOOTHNESS: IN AND OUTSIDE SEMICONDUCTOR INDUSTRY,” the entire contents of which are incorporated herein by reference. Without being bound by any particular theory, it is believed that, through the disclosed embodiments, the substrate can be smoothed due to a layer-by-layer mechanism by which ALE etches the material during each cycle, thereby etching and smoothing protrusions on the substrate surface. For example, protrusions on the surface of the material to be smoothed can be modified and etched such that, as the protrusion is etched, its size shrinks with each etch cycle, thereby smoothing the surface of the material.

[0102] While ALE processing can smooth sidewall or line edge roughness, it cannot alter CD variations, such as linewidth or hole / pillar diameter. Therefore, a selective carbonaceous material deposition process is used to selectively deposit on the photoresist structure, preferentially filling features with carbonaceous material at different deposition rates into features of different sizes. In various embodiments, the diameter of the holes or pillars is uniform across the substrate, improving LCDU. For example, in some embodiments, methane (CH4) can be used.

[0103] Back Figure 1 182a-182c illustrate exemplary schematic diagrams of selective deposition processes that can be performed according to certain disclosed embodiments. For selective polymer deposition, 182a shows a substrate having carbon atoms. In 182b, carbon is exposed to a carbon-containing chemical substance, such as methane (CH4), causing the carbon material to be selectively deposited onto the surface of the substrate. Although methane is used as an example, other carbon-containing chemicals can be used, which may have the chemical formula C. x H y Where x and y are integers greater than or equal to 1. Selective carbon deposition can be performed with low bias (e.g., self-bias power = about 5V to about 15V) and low RF plasma power in the range of about 30W to about 500W. In some embodiments, carbon-containing chemicals can be combined with one or more diluents to generate plasma. Exemplary diluents include nitrogen, helium, argon, hydrogen, and combinations thereof. In 182c, a purging chamber is used to remove excess polymer. The polymer remains on the surface of the carbon substrate.

[0104] Figure 4 This demonstrates how selective polymer deposition can reduce the presence of cracks and protrusions on photoresist. During 182b, carbon-containing chemicals (such as methane) are transported to the substrate and adsorbed onto the surface of the carbon-containing material on the substrate. Where gaps (e.g.) exist... Figure 4 In various embodiments of the photoresist substrate 400 (shown as gaps 450), a carbon-containing material 401 is deposited using a self-limiting process as described herein to fill the gaps 450 with the carbon-containing material, thereby smoothing the surface. Figure 4 As shown, selective deposition can also include deposition on protrusions (499), such as on photoresist. Without being bound by any particular theory, it is believed that since the scale of cracks on the surface of carbonaceous materials can be at the atomic level, depositing carbonaceous materials into these cracks, such that the carbonaceous material is uniformly adsorbed onto the surface of the substrate, will result in more material being deposited in the cracks than on the adjacent, relatively flat surfaces of the substrate, thereby reducing the presence of cracks with each deposition cycle.

[0105] In some embodiments, the substrate may also be exposed to an inert plasma after being exposed to a carbon-containing chemical substance. The inert plasma can be generated by flowing any one or more of hydrogen, helium, nitrogen, argon, and neon through it and igniting the plasma. The plasma can be ignited using a plasma power between about 30 W and about 500 W. Without being bound by any particular theory, it is believed that exposing the substrate to an inert plasma allows the adjacent surfaces of the carbon-containing material (e.g., photoresist) on the substrate to be slightly etched and / or refreshed to prevent deposition, thus resulting in selective deposition. Exposure to the carbon-containing chemical substance and the inert plasma can be performed in one or more cycles.

[0106] By using a combination of ALE technology and selective deposition as described herein, carbon-containing materials on substrates can be processed to produce smooth, uniform features, especially for EUV applications.

[0107] Figure 5 This is a process flow diagram illustrating the implementation of ALE and selective carbon deposition. Figure 5 The operation can be carried out in an indoor environment with a pressure between approximately 5 mTorr and approximately 100 mTorr. Figure 5 The operation can be performed at a substrate temperature between approximately 0°C and approximately 120°C, or between approximately 20°C and approximately 60°C. The substrate temperature should be understood as the temperature set at the base or wafer holder that will hold the substrate. Figure 5 The operations shown are summarized in the above reference. Figure 1 The operation performed. For example, in operation 402, a substrate comprising a carbon-containing material is provided to the chamber. As described above, the carbon-containing material may include a photoresist, graphene, or amorphous carbon. Operation 402 may correspond to Figure 1 The schematic diagrams depicted in 171a and 172a. In operation 403, the substrate is exposed to a modifying chemical substance, such as a strong or weak oxidizing agent, to modify the surface of the substrate. In many disclosed embodiments, carbonaceous material on the surface is modified. This operation may correspond to Figure 1 and Figure 2 The schematic diagrams depicted in 171b and 172b. In operation 405, the chamber is optionally purged to remove excess modified chemicals (e.g., weak oxidants, i.e., CO2) from the chamber. This operation may correspond to... Figure 1 and Figure 3172d. The chamber can be purged by evacuating the chamber or stopping the flow of the modifying chemical and allowing a non-reactive inert gas such as helium or argon to flow in, to remove excess gaseous modifying chemical. In operation 407, the substrate is exposed to an inert gas plasma to remove the modified surface. During operation 407, a bias is applied to generate sufficient energy for the inert gas plasma to remove the modified surface without sputtering the substrate. In operation 409, the chamber is optionally purged to remove the gaseous modifying material from the chamber. In operation 411, operations 403-409 can optionally be repeated cyclically. In operation 423, the substrate is exposed to a carbon-containing chemical to adsorb a layer of carbon-containing material onto the substrate. In some embodiments, this can be used to fill gaps on the carbon-containing surface of the substrate. This operation may correspond to Figure 1 and Figure 4 182a. In operation 424, the substrate is optionally exposed to an inert gas plasma to passivate regions of the substrate and enable selective deposition in subsequent cycles. In some embodiments, the chamber may be purged between operations 423 and 424. In some embodiments, the substrate may be purged once or multiple times between any of the described operations. In many embodiments, operations 423 and 424 may optionally be repeated cyclically, and the cycle may be performed with or without the purge operation between operations 423 and 424. In operation 425, the chamber may optionally be purged. It should be understood that any suitable purging technique may be used to perform the purging operation as described herein by evacuating gas from the chamber, by flowing one or more inert gases through, or a combination of both. In operation 498, it is determined whether the substrate has been sufficiently etched to form the desired surface on the substrate. If not, operations 403-498 may optionally be repeated n cycles, where n is an integer equal to or greater than 1. In some implementations, operations 423-425 are repeated only in some, but not all, repeating loops, while in other implementations, operations 423-425 are repeated in every loop.

[0108] By combining the ALE process and selective deposition process, both the LCDU and LER of the photoresist feature are improved. This improvement is then transferred to the underlying hard mask (e.g., a SiO2 / SiN layer) and thus to the structure of interest, resulting in improved variability and performance of the device.

[0109] ALE operation is gentle and precise, removing a digital amount of material per cycle, and can therefore be easily controlled to avoid over-etching the flexible resist material. Similarly, carbon-based selective deposition uses very low source power (e.g., transformer-coupled plasma or TCP) and does not use bias, and can perform deposition without damaging the resist.

[0110] In some implementations, selective carbon deposition may be optional. For example, some such implementations can be used in applications where increased critical dimensions can be tolerated.

[0111] In some implementations, if the original critical dimensions will be maintained throughout the patterning process using photoresist, the combination of the disclosed ALE operation and selective carbon deposition can be used on carbon-containing materials to improve the LCDU and restore the critical dimensions.

[0112] Device

[0113] The disclosed embodiments can be carried out in any suitable etching chamber or apparatus, such as those available from Lam Research Corporation in Fremont, California, USA. The process is performed in FX. Another example of a plasma etching chamber that can be used is the Flex, available from Lam Research Corp. in Fremont, California. TM Reactive ion etching tool. Further description of the plasma etching chamber can be found in U.S. Patent Nos. 6,841,943 and 8,552,334, the entire contents of which are incorporated herein by reference.

[0114] In some implementations, an inductively coupled plasma (ICP) reactor may be used. Figure 6An example is provided herein. Such an ICP reactor is also described in U.S. Patent No. 9,362,133, filed December 10, 2013, and granted June 7, 2016, entitled “METHOD FOR FORMING A MASK BY ETCHING CONFORMAL FILM ON PATTERNED ASHABLEHARDMASK,” which is incorporated herein by reference for describing a suitable ICP reactor for implementing the techniques described herein. While an ICP reactor is described herein, it should be understood in some embodiments that a capacitively coupled plasma reactor may also be used. An exemplary etching chamber or apparatus may include a chamber having chamber walls, a chuck for holding a substrate or wafer to be processed, an RF power supply configured to power a coil to generate plasma, and a gas inlet for input gases as described herein. The chuck may include electrostatic electrodes for clamping and releasing the wafer and may be charged using the RF power supply. For example, modified chemical gases and / or selective deposition chemicals may be flowed into the etching chamber to perform ALE and / or selective deposition, respectively. In some embodiments, the apparatus may include more than one chamber, each of which can be used to etch, deposit, or process a substrate. The chamber or apparatus may include a system controller for controlling some or all of the operations of the chamber or apparatus, such as regulating chamber pressure, inert gas flow rate, plasma power, plasma frequency, reactive gas flow rate (e.g., weak oxidizing gas, carbon-containing gas, etc.); bias power, temperature, vacuum settings; and other process conditions. The chamber may also be used to selectively deposit carbon-containing materials onto a substrate.

[0115] Figure 6 A schematic cross-sectional view of an inductively coupled plasma integrated etching and deposition apparatus 600 suitable for implementing certain embodiments of this document is shown, an example being Kiyo. TMThe reactor is manufactured by LamResearch Corp., Fremont, California. The inductively coupled plasma device 600 includes a main processing chamber 601 structurally defined by chamber walls and windows 611. The chamber walls may be made of stainless steel or aluminum. Windows 611 may be made of quartz or other dielectric materials. An optional internal plasma grid 650 divides the main processing chamber 601 into an upper sub-chamber 602 and a lower sub-chamber 603. In most embodiments, the plasma grid 650 can be removed, thereby utilizing the chamber space formed by sub-chambers 602 and 603. A chuck 617 is positioned in the lower sub-chamber 603 near its bottom inner surface. The chuck 617 is configured to receive and hold a wafer 619 on which etching and deposition processes are performed. The chuck 617 may be an electrostatic chuck for supporting the wafer 619 when it is present. In some embodiments, an edge ring (not shown) surrounds the chuck 617 and has an upper surface that is generally in the same plane as the top surface of the wafer 619 (when the wafer is present above the chuck 617). The chuck 617 also includes electrostatic electrodes for clamping and releasing the wafer. A filter and a DC clamping power source (not shown) may be provided for this purpose. Additional control systems may also be provided for lifting the wafer 619 away from the chuck 617. The chuck 617 can be charged with an RF power source 623. The RF power source 623 is connected to a matching circuit 621 via a connector 627. The matching circuit 621 is connected to the chuck 617 via a connector 625. In this way, the RF power source 623 is connected to the chuck 617.

[0116] The element for plasma generation includes a coil 633 located above window 611. In some embodiments, the coil is not used in the disclosed embodiments. The coil 633 is made of a conductive material and includes at least one full turn. Figure 6 The example of coil 633 shown includes three turns. The cross-section of coil 633 is indicated by symbols; coils with an "X" symbol indicate that coil 633 extends rotatably into the page, while coils with a "●" symbol indicate that coil 633 extends rotatably out of the page. The elements for plasma generation also include an RF power source 641 configured to provide RF power to coil 633. Generally, RF power source 641 is connected to matching circuit 639 via connector 645. Matching circuit 639 is connected to coil 633 via connector 643. In this way, RF power source 641 is connected to coil 633. An optional Faraday shield 649 is positioned between coil 633 and window 611. Faraday shield 649 is held in a spaced-apart relationship relative to coil 633. Faraday shield 649 is positioned directly above window 611. Coil 633, Faraday shield 649, and window 611 are each configured to be substantially parallel to each other. The Faraday shield prevents metal or other substances from depositing on the dielectric window 611 of the plasma chamber 601.

[0117] Process gases (e.g., oxygen, carbon dioxide, methane, etc.) can flow into processing chamber 601 through one or more main gas inlets 660 located in upper sub-chamber 602 and / or through one or more side gas inlets 670. Similarly, although not explicitly shown, similar gas inlets can be used to supply process gases to the capacitively coupled plasma processing chamber. A vacuum pump, such as a single-stage or two-stage dry mechanical pump and / or turbomolecular pump 640, can be used to evacuate process gases from processing chamber 601 and maintain pressure within processing chamber 601. For example, this pump can be used to evacuate chamber 601 during ALD purging operations. Valve-controlled conduits can be used to fluidly connect a vacuum pump to processing chamber 601 to selectively control the application of the vacuum environment provided by the vacuum pump. This can be done using closed-loop controlled flow limiting devices such as throttle valves (not shown) or pendulum valves (not shown) during plasma processing. Similarly, a vacuum pump and valves can be used that are fluidly connected to the capacitively coupled plasma processing chamber in a controlled manner.

[0118] During operation of the apparatus, one or more process gases may be supplied through gas inlets 660 and / or 670. In some embodiments, process gases may be supplied only through the main gas inlet 660 or only through the side gas inlet 670. In some cases, the gas inlets shown in the figures may be replaced by more complex gas inlets, for example, by one or more nozzles. The Faraday shield 649 and / or optional grid 650 may include internal channels and orifices that allow process gases to be delivered to chamber 601. One or both of the Faraday shield 649 and optional grid 650 may serve as nozzles for delivering process gases. In some embodiments, a liquid evaporation and delivery system may be located upstream of chamber 601 such that once a liquid reactant or precursor is evaporated, the evaporated reactant or precursor is introduced into chamber 601 through gas inlets 660 and / or 670.

[0119] Radio frequency (RF) power is supplied from RF power source 641 to coil 633 to cause RF current to flow through coil 633. The RF current flowing through coil 633 generates an electromagnetic field around coil 633. The electromagnetic field generates an induced current in upper sub-chamber 602. The generated ions and free radicals selectively etch features and deposit layers on wafer 619 through physical and chemical interactions.

[0120] If a plasma grid is used such that both an upper sub-chamber 602 and a lower sub-chamber 603 exist, an induced current acts on the gas present in the upper sub-chamber 602 to generate an electron-ion plasma in the upper sub-chamber 602. An optional internal plasma grid 650 limits the amount of hot electrons in the lower sub-chamber 603. In some embodiments, the device is designed and operated such that the plasma present in the lower sub-chamber 603 is an ion-ion plasma.

[0121] Both the upper electron-ion plasma and the lower ion-ion plasma can contain both cations and anions, but the ion-ion plasma will have a larger anion:cation ratio. Volatile etching and / or deposition byproducts can be removed from the lower sub-chamber 603 through port 622. The chuck 617 disclosed herein can operate over a temperature range ranging from about 10°C to about 250°C. This temperature will depend on the process operation and specific formulation.

[0122] When installed in a clean room or manufacturing plant, chamber 601 can be coupled to facilities (not shown). Facilities include piping that provides process gases, vacuum, temperature control, and environmental particulate control. These facilities are coupled to chamber 601 when installed in the target manufacturing plant. Furthermore, chamber 601 can be coupled to a transfer chamber, allowing for the use of typical automation to move semiconductor wafers in and out of chamber 601 by robots.

[0123] In some embodiments, system controller 630 (which may include one or more physical or logic controllers) controls some or all of the operations of the processing chamber. System controller 630 may include one or more memory devices and one or more processors. In some embodiments, the apparatus includes a switching system for controlling flow rate and duration when the disclosed embodiments are performed. In some embodiments, the apparatus may have a switching time of up to about 500 ms or up to about 750 ms. The switching time may depend on the flowing chemical substance, formulation selection, reactor architecture, and other factors.

[0124] Processing chamber 601 or apparatus may include a system controller, for example, in some embodiments, system controller 630 is part of a system that may be part of the examples described above. Such a system may include semiconductor processing equipment comprising one or more processing tools, one or more processing chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, airflow systems, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing semiconductor wafers or substrates. The electronics may be referred to as a “controller” that controls various elements or sub-components of one or more systems. Depending on the processing requirements and / or the type of system, system controller 630 may be programmed to control any process disclosed herein, including controlling process gas delivery, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, wafer transfer tools and other transfer tools, and / or loading locks connected to or interfaced with a specific system.

[0125] Broadly speaking, controller 630 can be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include chips in the form of firmware storing program instructions, digital signal processors (DSPs), chips defined as application-specific integrated circuits (ASICs), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions that communicate to the controller in the form of various individual settings (or program files) that define operating parameters for performing specific processes on or for a semiconductor wafer or system. In some embodiments, operating parameters may be part of a recipe defined by a process engineer for performing one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0126] In some implementations, controller 630 may be part of or coupled to a computer integrated with, coupled to, or connected via a network to the system or a combination thereof. For example, controller 630 may be in the “cloud” or be all or part of a fab host system, allowing remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of manufacturing operations, examine the history of past manufacturing operations, examine trends or performance criteria of multiple manufacturing operations, change parameters of the current process, set processing steps to follow the current process, or start a new process. In some instances, a remote computer (e.g., a server) may provide process recipes to the system via a network, which may include a local network or the Internet. The remote computer may include a user interface capable of inputting or programming parameters and / or settings that are then communicated from the remote computer to the system. In some instances, the controller receives instructions in the form of data specifying parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool to which the controller is configured to connect to or control the tool. Therefore, as described above, the controller can be distributed, for example, by comprising one or more discrete controllers connected together via a network and operating toward a common goal (e.g., the process and control described herein). An example of a distributed controller for these purposes could be one or more integrated circuits on a room that communicate with one or more remote integrated circuits (e.g., at the platform level or as part of a remote computer) integrated to control the process in the room.

[0127] Exemplary systems may include, but are not limited to, plasma etching chambers or modules, deposition chambers or modules, rotary cleaning chambers or modules, metal plating chambers or modules, cleaning chambers or modules, chamfering edge etching chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etching (ALE) chambers or modules, ion implantation chambers or modules, orbital chambers or modules, and any other semiconductor processing systems that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0128] As described above, depending on one or more process steps the tool is to perform, the controller 630 may communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the plant, a host, another controller, or tools used in material handling for moving wafer containers to and from tool locations and / or loading ports within the semiconductor manufacturing plant.

[0129] Processing chamber 601 can be integrated into, for example Figure 7In the multi-station tool shown, each station can be used to handle different operations. For example, one station can be used to perform ALE (Automatic Leakage) while another station performs selective deposition. The disclosed embodiments can be performed without breaking the vacuum and can be performed in the same apparatus. In many embodiments, ALE and selective deposition are performed without breaking the vacuum. In many embodiments, ALE and selective deposition are performed in the same chamber.

[0130] Figure 7 A semiconductor process cluster architecture is described, in which each module interfaces with a vacuum transfer module 738 (VTM). The configuration of a transfer module that “transfers” wafers between multiple memory devices and processing modules can be referred to as a “cluster tooling architecture” system. A hermetically sealed module 730 (also referred to as a load lock or transfer module) is shown in the VTM 738 having four processing modules 720a-720d, which can be individually optimized to perform various manufacturing processes. For example, processing modules 720a-720d can be implemented to perform substrate etching, deposition, ion implantation, wafer cleaning, sputtering, and / or other semiconductor processes. In some embodiments, ALE and selective deposition are performed in the same module. In some embodiments, ALE and selective deposition are performed in different modules within the same tooling. One or more of the substrate etching processing modules (any one or more of 720a-720d) can be implemented as disclosed herein, i.e., for performing ALE, selectively depositing carbon-containing materials, and other suitable functions according to the disclosed embodiments. The hermetic module 730 and the processing module 720 can be referred to as "stations". Each station has a facet 736 that connects the station to the VTM 738. Inside each facet, sensors 1-18 are used to detect the passage of the substrate 726 as it moves between stations.

[0131] Robotic arm 722 transfers wafer 726 between stations. In one embodiment, robotic arm 722 has one arm, while in another embodiment, robotic arm has two arms, each with an end effector 724 to pick up wafers (e.g., wafer 726) for transport. In the Atmospheric Transfer Module (ATM) 740, a front-end robotic arm 732 is used to transfer wafer 726 from a wafer cassette or front-opening standard cassette (FOUP) 734 in the Load Port Module (LPM) 742 to the hermetic module 730. Module center 728 within the processing module 720 is a location for placing wafer 726. Aligner 744 in the ATM 740 is used to align the wafer.

[0132] In one exemplary processing method, a wafer is placed in one of a plurality of FOUPs 734 within an LPM 742. A front-end robot 732 transfers the wafer from the FOUP 734 to an alignment unit 744, which allows the wafer 726 to be properly centered before etching or processing. After alignment, the wafer 726 is moved by the front-end robot 732 into a hermetically sealed module 730. Because the hermetically sealed module has the ability to match the environments between ATM and VTM, the wafer 726 can move between the two pressure environments without damage. From the hermetically sealed module 730, the wafer 726 is moved by the robot 722 through the VTM 738 and into one of the processing modules 720a-720d. To achieve this wafer movement, the robot 722 uses end effectors 724 on each of its arms. Once the wafer 726 has been processed, it is moved from the processing modules 720a-720d into the hermetically sealed module 730 by the robot 722. The chip 726 can be moved from here to one of the multiple FOUPs 734 or to the aligner 744 via the front-end robot 732.

[0133] It should be noted that the computer controlling the movement of the chip can be local to the cluster architecture, or it can be located outside the cluster architecture in the manufacturing plant, or at a remote location connected to the cluster architecture via a network. (See above for reference.) Figure 6 The controller can be used Figure 7 The tools implemented in the process.

[0134] experiment

[0135] Experiment 1

[0136] Experiments were conducted on carbon-containing photoresist. The substrate before the etching process was as follows: Figure 8A As shown.

[0137] Conventional RIE etching is performed by exposing the substrate to HBr at 20°C and a plasma power of 900W for 15 seconds. The resulting substrate is... Figure 8B middle.

[0138] In another experiment, the substrate was exposed to 10 cycles of ALE at 60°C. The procedures included exposure to CO2 plasma, scavenging, exposure to helium plasma with low bias, and scavenging. The resulting photoresist exhibited smooth sidewalls and reduced roughness, and improved LER. Wrinkling was reduced, and photoresist dross was decreased. The resulting substrate... Figure 8C middle.

[0139] In another experiment, the substrate was exposed to 10 cycles of ALE at 20°C. The procedures included exposure to CO2 plasma, purging, exposure to helium plasma with low bias, and purging. The resulting substrate is shown below. Figure 8D As shown.

[0140] In another experiment, the substrate was exposed to 10 cycles of ALE at 60°C. These operations included exposure to CO2 plasma, purging, exposure to helium plasma with low bias, and purging. The resulting substrate is shown below. Figure 8E As shown.

[0141] Performing ALE resulted in significantly smoother lines on the substrate. These results indicate that ALE can be performed at 20°C.

[0142] Experiment 2

[0143] Experiments were conducted, with ALE (Alternating Light Etching) of the photoresist undergoing 3 cycles and 5 cycles. Substrates without ALE were also tested. Figures 9A-9C As shown.

[0144] The substrate was exposed to three cycles of ALE operation, which included exposure to CO2 plasma, purging, exposure to helium plasma with low bias, and purging. The substrate after three cycles appeared as follows: Figures 10A-10C As shown.

[0145] The substrate was exposed to five cycles of ALE operation, which included exposure to CO2 plasma, purging, exposure to helium plasma with low bias, and purging. The substrate after five cycles appeared as follows: Figure 11A-11C As shown.

[0146] in conclusion

[0147] While the foregoing embodiments have been described in considerable detail for the purpose of clarity, it will be apparent that certain variations and modifications may be made within the scope of the disclosed embodiments. It should be noted that many alternative processes, systems, and apparatuses exist for implementing the embodiments of the present invention. Therefore, the embodiments of the present invention should be considered illustrative rather than restrictive, and are not limited to the details given herein.

Claims

1. A method for processing a substrate, the method comprising: (a) Exposing a substrate containing a first carbon-containing material to an oxygen-containing oxidant and igniting a first plasma to modify the surface of the first carbon-containing material; as well as (b) Exposing the modified surface to a second plasma formed by an inert gas under a bias voltage for a duration sufficient to remove the modified surface without sputtering.

2. The method of claim 1, further comprising (c) selectively depositing a second carbon-containing material on the substrate to fill the gaps in the first carbon-containing material.

3. The method of claim 2, wherein selectively depositing the second carbon-containing material on the substrate comprises applying a self-bias with a voltage between about 5V and about 15V, and igniting the plasma with a plasma power between about 30W and about 500W.

4. The method of claim 3, wherein selectively depositing the second carbon-containing material on the substrate further comprises introducing methane.

5. The method of claim 4, wherein selectively depositing the second carbon-containing material on the substrate further comprises introducing a diluent selected from nitrogen, helium, argon, hydrogen, and combinations thereof.

6. The method of claim 2, wherein (c) comprises exposing the substrate to methane to adsorb the layered methane onto the surface of the first carbon-containing material and exposing the substrate to a third plasma.

7. The method of claim 1, wherein the bias voltage is capable of being between about 30V and about 100V.

8. The method according to claim 1, wherein the oxidant is a strong oxidant.

9. The method of claim 8, wherein the strong oxidizing agent is oxygen.

10. The method of claim 8, wherein the first plasma is generated using a plasma power between about 15 W and about 500 W.

11. The method of claim 8, wherein the first plasma is generated with a bias voltage between about 5V and 50V.

12. The method according to claim 1, wherein the oxidant is a weak oxidant.

13. The method of claim 12, wherein the weak oxidant is selected from carbon dioxide, carbon monoxide, sulfur dioxide, nitric oxide, nitrogen, and ammonia.

14. The method of claim 12, wherein the first plasma is generated using a plasma power between about 30 W and about 500 W.

15. The method of claim 12, wherein the first plasma is ignited with another bias voltage between about 30V and about 100V.

16. The method according to claim 1, wherein the first carbon-containing material is selected from photoresist, amorphous carbon, and graphene.

17. The method of claim 1, wherein the first carbon-containing material is a photoresist patterned by extreme ultraviolet lithography.

18. The method of claim 1, wherein the second plasma in (b) is generated and ignited by introducing an inert gas selected from hydrogen, helium, nitrogen, argon and neon.

19. A method for processing a substrate, the method comprising: (a) Exposing a substrate containing a first carbon-containing material to an oxygen-containing oxidant and igniting a first plasma to modify the surface of the first carbon-containing material; (b) Exposing the modified surface to a second plasma formed by an inert gas under bias power for a duration sufficient to remove the modified surface without sputtering; as well as (c) Selectively depositing a second carbon-containing material on the substrate to fill the gaps in the first carbon-containing material with a precursor having the chemical formula CxHy, wherein x and y are integers greater than or equal to 1.

20. The method of claim 19, wherein the precursor comprises methane.

Images