Codeposition and etching process

Abstract

A method of selectively etching at least one feature in an etch layer of a doped or undoped material of at least one of silicon, silicon germanium, carbon, and germanium relative to a mask is provided. While selectively etching at least one feature in the etch layer relative to the mask and selectively depositing the deposition layer is provided by providing an etch gas comprising a metalloid or metal-containing precursor and a halogen or oxygen-containing component, forming the etch gas into a plasma, and exposing the etch layer to the plasma, the etch layer is disposed over the mask to simultaneously selectively etch at least one feature in the etch layer with respect to the mask and selectively deposit a deposition layer containing a metalloid or metal material over the mask with respect to the etch layer.

Description

Technical Field

[0001] This application claims priority to U.S. Application No. 63 / 337,307, filed on May 2, 2022, which is incorporated herein by reference for all purposes. Background Art

[0002] The background description provided here is for the purpose of generally presenting the context of the present disclosure. The information described in this background section and aspects of the specification that were not determined to be prior art at the time the application was filed are neither explicitly nor implicitly admitted to be prior art against the present disclosure.

[0003] The present disclosure relates to methods of forming semiconductor devices on semiconductor wafers. More particularly, the present disclosure relates to selectively etching an etch layer relative to a mask (eg, a hard mask).

[0004] The minimum feature size of semiconductor devices continues to shrink to follow Moore's Law. In the formation of silicon fins and nanosheets, features with small widths and high aspect ratios are etched into silicon or carbon. Silicon oxide (SiO) or photoresist can be used as a mask. Improved etch selectivity allows thinner masks, thereby improving resolution. Summary of the invention

[0005] To achieve the above-mentioned object and in accordance with the object of the present disclosure, a method is provided for selectively etching at least one feature in an etching layer of a doped or undoped material of at least one of silicon, silicon germanium, carbon and germanium relative to a mask. The selective etching of at least one feature in the etching layer relative to the mask and the selective deposition of a deposition layer are provided by providing an etching gas comprising a precursor containing a metalloid or a metal and a component containing a halogen or oxygen, forming the etching gas into a plasma, and exposing the etching layer to the plasma to selectively etch at least one feature in the etching layer relative to the mask and selectively deposit a deposition layer containing a metalloid or a metal over the mask relative to the etching layer.

[0006] These and other features of the present disclosure will be described in more detail below in the detailed description of the disclosure and in conjunction with the following figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present disclosure is illustrated by way of example and not limitation in the accompanying figures and in which like reference numerals indicate similar elements and in which:

[0008] Figure 1 is a high-level flow chart of the implementation plan.

[0009] Figure 2A-2D is a schematic cross-sectional view of a structure processed according to an embodiment.

[0010] Figure 3A-3B is a photograph of a cross-sectional view of a portion of a structure processed according to an embodiment.

[0011] Figure 4A-4B is a photograph of a cross-sectional view of a portion of a structure processed according to another embodiment.

[0012] Figure 5A-Figure 5B is a photograph of a cross-sectional view of a portion of a structure processed according to another embodiment.

[0013] Figure 6 is a schematic diagram of an etching chamber that can be used in one embodiment.

[0014] Figure 7 is a schematic diagram of a computer system that can be used to implement an embodiment. DETAILED DESCRIPTION

[0015] The present invention will now be described in detail with reference to several exemplary embodiments shown in the accompanying drawings. In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without some or all of these specific details. In other cases, known process steps and / or structures are not described in detail to avoid making the present invention unclear unnecessarily.

[0016] During the formation of semiconductor devices, silicon can be etched. Sometimes, silicon or carbon can be etched to form silicon fins and silicon nanosheets and carbon features. Silicon nanosheets are two-dimensional nanostructures of silicon with a thickness ranging from 1 nanometer (nm) to 100nm. For some front-end processes, the addition of metal contaminants may change the semiconductor properties of silicon. Therefore, for some front-end processes, metal-containing gases are avoided. In such a process, if a hard mask is used, the hard mask will not have metal. In some silicon etching processes, such as strained source drain (SSD) structure formation processes, silicon can be etched using silicon nitride (SiN) or silicon oxide (SiO2) hard masks. In some pattern transfer processes, amorphous carbon can be etched using photoresist (PR). In order to achieve good etching selectivity, metal-containing PR can be used instead of hydrocarbon polymer-based PR.

[0017] In the present disclosure, new processes and apparatus are described. The processes and apparatus enable selective etching of an etch layer of doped or undoped silicon, silicon germanium, germanium, or carbon relative to a mask. In various embodiments, the mask is a hard mask. In various embodiments, the mask is a photoresist (PR), such as a PR containing a metal. The process is capable of simultaneously etching the etch layer while depositing a layer containing a metalloid or metal over the mask.

[0018] For ease of understanding, Figure 1 1 is a high-level flow chart of a process used in an embodiment. A structure having an etch layer including a mask is provided (step 104). In some embodiments, the etch layer may be a doped or undoped material of at least one of silicon, silicon germanium, and germanium. In other embodiments, the etch layer may be carbon, such as amorphous carbon. An optional pre-etch (step 108) may also be provided to selectively etch the etch layer relative to the mask portion, such as a penetration process. Such a pre-etch may partially etch the mask.

[0019] Provide selective etching of the etching layer and selective deposition on the mask (step 112). The selective etching of the etching layer and the selective deposition on the mask (step 112) are co-deposition and etching processes. The selective etching of the etching layer and the selective deposition on the mask include a process of selective deposition of the deposition layer on the mask (step 116) and a process of selective etching of the etching layer (step 120). In some embodiments, the process of selective deposition on the mask (step 116) is performed by atomic layer deposition (ALD) or plasma enhanced atomic layer deposition (PEALD). In some embodiments, the selective deposition process on the mask (step 116) includes providing a deposition component containing a precursor containing a metalloid or a metal, and forming the deposition component into a plasma during plasma enhanced chemical vapor deposition (PECVD). In some embodiments, the process of selective etching of the etching layer (step 120) is performed by reactive ion etching (RIE). In some embodiments, the process of selective etching of the etching layer (step 120) is performed by atomic layer etching (ALE). In some embodiments, the process of selectively etching the etch layer (step 120) includes providing an etching component including a halogen-containing component and forming the halogen-containing component into a plasma during RIE.

[0020] In various embodiments, the halogen-containing component comprises at least one of chlorine, bromine, iodine, and fluorine. In various embodiments, the halogen-containing component comprises at least one of hydrogen bromide (HBr), hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen iodide (HI), chlorine (Cl2), boron trichloride (BCl3), fluorocarbons (such as carbon tetrafluoride (CF4), hexafluorobutadiene (C4F6), and octafluorocyclobutane (C4F8)), and fluorinated hydrocarbons (such as fluoromethane (CH3F), difluoromethane (CH2F2), and trifluoromethane (CHF3)) to etch silicon, silicon germanium, and germanium. In other embodiments, an oxygen-containing component comprising at least one of oxygen (O2), ozone (O3), carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS), nitrogen dioxide (NO2), nitrates (NO3), and sulfur dioxide (SO2) is provided to etch amorphous carbon. In various embodiments, the etching of carbon can be performed by a mixture of a halogen-containing component and an oxygen-containing component to etch carbon. For example, in some embodiments for etching an amorphous carbon layer, the etching gas can include CH2F2 and O2, or can include methane (CH4) and O2, or can include HBr and O2.

[0021] In some embodiments, the process of selective deposition on the mask (step 116) and the process of selective etching of the etching layer (step 120) are performed simultaneously. In some embodiments in which the process of selective deposition on the mask (step 116) and the process of selective etching of the etching layer (step 120) are performed simultaneously, at least one of PECVD, PEALD, and ALD is used to provide the selective deposition on the mask (step 116), and at least one of RIE and ALE is used to selectively etch the etching layer (step 120). In some embodiments in which the process of selective deposition on the mask (step 116) and the process of selective etching of the etching layer (step 120) are performed simultaneously, an etching gas is provided, which contains an etching component and a deposition component at the same time, and the etching component includes an etching component having a halogen component and / or an etching component having an oxygen component, and the deposition component contains a precursor having a metalloid or a metal. The etching gas is formed into a plasma. In some embodiments, both the deposition component and the etching component are formed into a plasma at the same time. In other embodiments, the process of selective deposition on the mask (step 116 ) and the process of selective etching of the etch layer (step 120 ) are cyclically performed for a plurality of cycles.

[0022] After the selective etching and deposition (step 112), an optional post-etching (step 124) may be provided. The optional post-etching (step 124) may be used to further etch the etching layer and / or remove any remaining deposits on the mask, and may also be used to remove any remaining mask. In some embodiments, the post-etching (step 124) is used to remove all remaining deposits on the mask. In some embodiments, other processes may be used to remove the remaining deposits on the mask. In addition, other processes may be used to remove the remaining deposition and mask on the mask. In some embodiments, other processes may be used to remove the mask. In some embodiments, a cyclic process may be used by returning to the selective etching of the etching layer and the selective deposition (step 112) on the mask after the post-etching (step 124).

[0023] Since some embodiments selectively deposit on the mask when the etching layer is selectively etched, a thinner mask can be used to etch features deeper. In addition, the concentration and / or ratio of the etching component and the deposition component provide a knob that can be used to control different etching characteristics, such as the etching ratio of dense features to isolated features, etching rate, curvature, etching front roughness, and etching selectivity. As a result, some embodiments can reduce curvature, reduce mask loss, and reduce isolation-dense load. Since various embodiments do not rely on nucleation delay or self-assembled monolayers (which lose selectivity over time), the overall selectivity provided by some embodiments that provide simultaneous deposition and etching is improved by avoiding undesirable deposition on the etching layer. Example 1

[0024] In some embodiments, providing a structure having an etch layer beneath the mask (step 104) provides a silicon etch layer beneath the silicon oxide mask. Figure 2A is a schematic cross-sectional view of a portion of structure 200 having an etch layer 204 and a mask 208. A native silicon oxide layer 212 is formed over a surface of the silicon etch layer 204.

[0025] In some embodiments, an optional pre-etch (step 108) is provided. In some embodiments, the pre-etch (step 108) etches the etch layer 204. In some embodiments, the pre-etch (step 108) etches the mask 208. In some embodiments having a silicon etch layer 204 and a native silicon oxide layer 212, a penetration step to remove the silicon oxide 212 is provided as part of the pre-etch (step 108). In some embodiments, the penetration step provides a CF4-based plasma to remove the silicon oxide 212. In some embodiments, if native silicon oxide 212 is present, a penetration step will be required. In some embodiments, where a pre-etch has been performed and the structure has not been exposed to oxygen, so that no native oxide is formed on the silicon etch layer 204, a penetration step is not required. In addition, in some embodiments, if the etch layer 204 is carbon, a penetration step may not be required. In some embodiments, the pre-etch step (step 108) includes providing atomic layer etching. In some embodiments where the etch layer 204 is a silicon layer, the pre-etch step is an atomic layer etch, which includes a modification phase of providing a chlorine plasma or a thermal chlorine (Cl2) plasma with no bias or low bias so as to modify a portion of the etch layer 204; and a sputtering phase of providing an argon (Ar) or helium (He) plasma with a bias to cause bombardment and sputtering of the modified portion of the etch layer 204. In some embodiments, a sweep may be provided between the different phases.

[0026] Figure 2B 2 is a schematic cross-sectional view of a portion of structure 200 after pre-etching. The native oxide layer has been etched away. In some embodiments, some of etch layer 204 and some of mask 208 may also be etched away, thereby forming etch features 220 in etch layer 204. In some embodiments, part of the pre-etching step (step 108) is a breakthrough etch. In some embodiments, after the breakthrough etch, the pre-etch uses atomic layer etching to further etch etch layer 204.

[0027] After the optional pre-etching step (step 108), selective etching of the etching layer and selective deposition on the mask (step 112) are provided. In some embodiments, selective deposition (step 116) and selective etching (step 120) are provided simultaneously. In some embodiments, the etching gas includes boron trichloride (BCl3), nitrogen (N2) and hydrogen bromide (HBr). In some embodiments, the deposition component includes a boron precursor containing a metalloid or metal in BCl3. The etching component includes a component containing a halogen. The component containing a halogen includes HBr and BCl3. The etching gas is formed into a plasma. The plasma selectively deposits a boron nitride layer on the mask 208 and selectively etches the etching layer 204.

[0028] Figure 2C1 is a schematic cross-sectional view of a portion of structure 200 after providing selective etching of the etch layer and selective deposition on the mask (step 112). In some embodiments, a boron nitride (BN) deposition layer 216 is deposited over mask 208, and etch layer 204 is etched. In some embodiments using etching gases of BCl3, N2, and Cl2, the selective etching of the etch layer and the selective deposition on the mask deposits the BN deposition layer 216 on mask 208 and etches the etch layer 204. In other embodiments using etching gases of BCl3, N2, and HBr, the selective etching of the etch layer and the selective deposition on the mask deposits the BN deposition layer 216 on mask 208 and etches the etch layer 204.

[0029] After the selective etching of the etching layer and the selective deposition on the mask (step 112), an optional post-etching (step 124) is provided. The post-etching (step 124) can be used to etch one or more of the deposition layer 216, the etching layer 204, and the mask 208. In some embodiments, the selective etching of the etching layer and the selective deposition on the mask (step 112) remove the deposition layer 216 on the mask 208, so that the post-etching (step 124) etches only the mask 208. In some embodiments, the optional post-etching (step 124) includes providing atomic layer etching. In some embodiments, the atomic layer etching includes a modification phase of providing chlorine plasma or thermal plasma under no bias or low bias to modify a portion of the etching layer 204; and a sputtering phase of providing argon (Ar) or helium (He) plasma under bias to cause bombardment and sputtering of the modified portion of the etching layer 204.

[0030] Figure 2D is a schematic cross-sectional view of a portion of structure 200 after an optional post-etch (step 124) used in some embodiments. The BN deposited layer is at least partially etched. In some embodiments, the BN deposited layer is completely etched away.

[0031] In some embodiments, further etching may be desired. However, the deposits on the mask, such as the BN deposited layer, have been removed. Therefore, in some embodiments, the process provides another cycle of selective etching of the etch layer and selective deposition on the mask (step 112), followed by post-etching (step 124). The cycle can be repeated until the desired etching depth is reached.

[0032] In some embodiments, the selective deposition (step 116) includes PECVD deposition of nitrides such as BN, SiN, and WNx, and the selective etching (step 120) includes RIE of a silicon etch layer. In some embodiments, at least one of BCl3, silicon tetrachloride (SiCl4), and WF6 can be used with N2 to provide BN, SiN, or WNx deposition and Br or Cl radicals to etch Si. For example, a plasma formed from BCl3, N2, and HBr can be used to provide simultaneous selective deposition (step 116) and selective etching (step 120).

[0033] Figure 3A is a photograph of a cross-sectional view of a portion of structure 200 after feature 220 has been etched into etch layer 204 according to some embodiments. In some embodiments, the etching gas includes BCl3, N2, and HBr. The ratio of the flow rates of the components of the etching gas can be optimized. In some embodiments, the flow rate of boron is approximately the same as the flow rate of nitrogen, where the ratio of boron to nitrogen is between 1:1 and 1:3. In some embodiments, the ratio of the flow rate of HBr to the flow rate of BCl3 is approximately 1:1, so that there is enough etchant gas to provide selective etching without over-etching. In some embodiments, the ratio of the molar flow rates of BCl3 to N2 to HBr is approximately 1:1:2. In some embodiments, an Ar or He diluent can be added to the etching gas. Figure 3A In FIG. 2 , all etched features 220 are narrow and close together, so that features 220 are dense features.

[0034] Figure 3B 2 is a photograph of a cross-sectional view of another portion of structure 200 that has been etched. In this portion of structure 200, some of features 220 are narrow and therefore densely packed, while other features 304 are wide and therefore isolated. Figure 3A In , for dense features 220, about 42.58 nm of mask 208 remains, while dense features 220 are etched by about 62.01 nm. Figure 3B In the embodiment, about 42.99 nm of mask 208 remains, while dense features are etched by 61.60 nm, and isolated features 304 are etched by about 62.01 nm. In addition, the etch front of isolated features 304 is relatively flat. This shows that the embodiment can provide both isolated features and dense features that can be etched at approximately equal rates, and can also provide a relatively flat etch front for wide features. Example 2

[0035] In some embodiments, a different etch gas recipe is provided starting with the same structure 200 and the same pre-etch (step 108) as in Example 1. The etch gas has been optimized to have a molar flow ratio of BCl3 to N2 to HBr of about 1:1:1. Figure 4A is a photograph of a cross-sectional view of a portion of structure 200 after features 220 have been etched into etch layer 204, according to some embodiments. Figure 4A In FIG. 5 , all etched features 220 are narrow and close together, so that the features 220 are dense features. Figure 4B 2 is a photograph of a cross-sectional view of another portion of structure 200 that has been etched, according to some embodiments. In this portion of structure 200, some features 220 are narrow and therefore densely packed, while other features 404 are wide and therefore isolated. Figure 4A In FIG. 1 , for dense features 220, about 45.48 nm of mask 208 remains, while dense features 220 are etched by about 52.92 nm. Figure 4B In the embodiment of the present invention, about 45.48 nm of mask 208 remains, while the dense features are etched 55.81 nm, and the isolated features 404 are etched about 50.02 nm. In addition, the etch front of the isolated features 404 is not as flat as in the previous embodiment. In some embodiments, there is more loading, so that the dense features are etched more than the isolated features. In addition, the isolated features are not as flat as in the previous embodiment. Example 3

[0036] In some embodiments, a different etch gas recipe is provided starting with the same structure 200 and the same pre-etch (step 108) as in Example 1. The etch gas has been optimized to have a molar flow ratio of BCl3 to N2 to HBr of about 1:1:4. Figure 5A is a photograph of a cross-sectional view of a portion of structure 200 after features 220 have been etched into etch layer 204, according to some embodiments. Figure 5A In FIG. 2 , all etched features 220 are narrow and close together, making the features 220 dense features. Figure 5B 2 is a photograph of a cross-sectional view of another portion of structure 200 that has been etched, according to some embodiments. In this portion of structure 200, some of features 220 are narrow and therefore densely packed, while other features 504 are wide and therefore isolated. Figure 5A In FIG. 1 , for dense features 220, about 41.75 nm of mask 208 remains, while dense features 220 are etched about 71.11 nm. Figure 5BIn the embodiment of the present invention, about 41.75 nm of mask 208 remains, while the dense features are etched 71.11 nm, and the isolated features 504 are etched about 87.64 nm. In addition, the etching front of the isolated features 504 is flat. In some embodiments, the isolated features are etched more than the dense features.

[0037] The above examples show how to use different ratios of gases to adjust the etch rate between isolated features and dense features. In addition, such ratios can be used to further adjust the degree of curvature and the amount of deposition on the mask. In some embodiments, the flow rate of the gas component deposited on the mask can also be adjusted to deposit as a sidewall passivation to prevent curvature. By adjusting the amount of deposition on the mask, the amount of curvature can be adjusted.

[0038] In some embodiments, the selective deposition (step 116) includes PECVD deposition of carbides such as boron carbide (B4C), silicon carbide (SiC), and tungsten carbide (WCx), and the selective etching (step 120) includes RIE of the silicon etch layer. In some embodiments, at least one of BCl3, SiCl4, and WF6 can be used with CH4 and Cl2 to provide B4C, SiC, or WCx deposition and Br or Cl radicals to etch Si. For example, a plasma formed from SiCl4, CH4, and Cl2 can be used to provide simultaneous selective deposition (step 116) and selective etching (step 120).

[0039] In some embodiments, the selective deposition (step 116) includes PEALD deposition of fluoride, and the selective etching (step 120) includes RIE of the silicon etch layer. In some embodiments, thermal trimethylaluminum (Al(CH3)3, or TMA) can be used in a plasma formed from at least one of NF3, CF4, and sulfur hexafluoride (SF6). In the ALD process, aluminum trifluoride is deposited on the mask. Fluorine radicals are used to etch silicon.

[0040] In some embodiments, the selective deposition (step 116) includes PEALD deposition of oxides such as boron oxide (B2O3, B2O and / or B6O), SiO2, tungsten oxide (W2O3, WO2 and / or WO3), titanium oxide (TiO, TiO2 and / or Ti2O3), and tin oxide (SnO and / or SnO2) on a mask of at least one of SiN, SiO2, or a metal-containing PR, and the selective etching (step 120) includes RIE of a carbon etch layer. In some embodiments, a plasma may be formed from at least one of O2 and CH4 or CO2 and CH4 and WF6 to provide deposition on the mask and oxygen radicals for etching carbon.

[0041] In some embodiments, the selective deposition (step 116) includes PEALD deposition of fluoride, and the selective etching (step 120) includes RIE of the carbon etch layer. In some embodiments, thermal TMA can be used in a plasma formed by CH2F2 and O2. In the ALD process, aluminum trifluoride (AlF3) is deposited on the mask. Oxygen radicals or ions are used to etch the carbon etch layer.

[0042] In some embodiments, the etching gas includes BCl3, N2, hydrogen (H2) and chlorine (Cl2). In some embodiments, an inert diluent such as a noble gas can be added to the etching gas. In some embodiments, an inert gas He or Ar can be added to the etching gas. In some embodiments, Cl2 provides a halogen. In some embodiments, the etching gas includes BCl3, N2 and hydrogen chloride (HCl). In some embodiments, a metal-containing deposit, such as BN, boron oxide, boron carbide, SiN, SiO2 and SiC, is deposited instead of a metal-containing deposit. The embodiment does not contain pollutants containing metals. The metal-free process may be required during certain semiconductor processes, such as some front-end processes. In other embodiments, aluminum pollutants are acceptable so that deposits of aluminum compounds such as AlF3, aluminum oxide (Al2O3) and aluminum nitride (AlN) can be deposited above the mask. In other embodiments, at least one of tungsten hexafluoride (WF6), tin tetrachloride (SnCl4), and titanium tetrachloride (TiCl4) is a metal-containing precursor used to deposit a metal-containing deposit having at least one of W, Sn, Ti over the mask. In various embodiments, the metalloid or metal-containing precursor is a precursor having at least one of boron, silicon, carbon, nitrogen, aluminum, fluorine, chlorine, tungsten, molybdenum, titanium, tin, tantalum, hafnium, zirconium, hydrogen, and oxygen. In various embodiments, the precursor can be one or more of BCl3, trimethylborane (B(CH3)3), triethylborane (B(C2H5)3), silicon tetrachloride (SiCl4), silane (SiH4), trimethylaluminum (Al(CH3)3), dimethylaluminum chloride ((CH3)2AlCl), tungsten hexafluoride (WF6), tungsten pentachloride (WCl5), molybdenum hexafluoride (MoF6), molybdenum pentachloride (MoCl5), titanium tetrachloride (TiCl4), titanium tetrafluoride (TiF4), tin tetrachloride (SnCl4), tetramethyltin (Sn(CH3)4), tantalum pentachloride (TaCl5), tantalum pentafluoride (TaF5), hafnium tetrachloride (HfCl4), tetrakis(dimethylamidohafnium)(Hf[N(CH3)2]4), zirconium tetrachloride (ZrCl4), and tetrakis(dimethylamidozirconium)(Zr[N(CH3)2]4).

[0043] Some embodiments allow for selective deposition of a mask containing a metalloid relative to a doped or undoped material of at least one of silicon, silicon germanium, carbon and germanium on SiN, SiO2 or a photoresist, while etching a doped or undoped material of at least one of silicon, silicon germanium, carbon and germanium. The embodiments may be free of hydrofluorocarbons and fluorocarbons. Some embodiments have carbon-free deposition. Various embodiments can be selectively deposited on a mask relative to an etching layer while etching the etching layer. In some embodiments, selective deposition is not only controlled by topology, but is selectively deposited according to the chemical property difference between the mask and the etching layer. Various embodiments provide an etching gas, which, in addition to a gas containing a metal or metalloid precursor, also contains a gas containing a halogen, wherein the etching gas does not contain hydrofluorocarbons and fluorocarbons. Some embodiments allow for selective deposition relative to carbon on a photoresist while etching a carbon etching layer.

[0044] By depositing and etching the etch layer 204 on the mask 208 at the same time, the etching can have a higher yield. In addition, it has been found that using a separate deposition step and a separate etching step will result in lower quality etching. The lower quality will result in features having different etching depths. Moreover, having separate deposition and etching steps results in isolated features being etched to a depth different from the depth of dense features. In addition, the bottom of the isolated features is rough, not flat. The process of not depositing and etching at the same time relies only on the deposition selectivity. Over time, some deposits will appear on the etching layer, causing the deposition selectivity to be lost. By depositing and etching at the same time, the deposition selectivity can be maintained for a longer time. Some embodiments using simultaneous deposition and etching provide higher quality deposition and etching. In some embodiments, features having a width of less than 15nm and a depth-to-width ratio of at least 6:1 can be provided. In some embodiments, in order to etch the carbon layer using a photoresist mask, the features have a width of less than 15nm and a depth-to-width ratio of less than 3:1. For example, the depth-to-width ratio is in the range of about 1:1 to 2:1. Some embodiments allow for selective etching of features in the etch layer while maintaining the structure at a temperature below 400°C. In some embodiments, the structure is maintained at a temperature below 300°C. For example, the structure is maintained at a temperature below 150°C. Maintaining the structure below 300°C reduces thermal effects or thermal damage to the structure. In some embodiments where the etch layer is silicon, at least 60 nm of the etch layer 204 is etched. In some embodiments, at least 100 nm of the etch layer 204 is etched. Some embodiments allow for a high aspect ratio of height to depth, thereby allowing for a deeper etch depth.

[0045] In one embodiment, Figure 6An example of a plasma processing system 600 that can be used in some embodiments is schematically depicted. According to some embodiments, the plasma processing system 600 can be used to process a substrate 601. The plasma processing system 600 includes a plasma reactor 602 having a plasma processing chamber 604 surrounded by a chamber wall 662. A plasma power source 606 tuned by a matching network 608 provides power to a transformer coupled plasma (TCP) coil 610 located near a power window 612 to generate a plasma 614 in the plasma processing chamber 604 by providing inductively coupled power. The TCP coil (upper power source) 610 can be configured to generate a uniform diffusion profile within the plasma processing chamber 604. For example, the TCP coil 610 can be configured to generate a toroidal power distribution in the plasma 614. The power window 612 is set to separate the TCP coil 610 from the plasma processing chamber 604 while enabling energy to be transferred from the TCP coil 610 to the plasma processing chamber 604. A wafer bias voltage power source 616 tuned by a bias matching network 618 provides power to an electrode 620 to set a bias voltage on the substrate 601. The electrode 620 provides a chuck for the substrate 601, wherein the electrode 620 acts as an electrostatic chuck and a substrate support. A substrate temperature controller 666 is controllably connected to a Peltier heater / cooler 668. A controller 624 controls the plasma power source 606, the substrate temperature controller 666, and the wafer bias voltage power source 616.

[0046] Plasma power source 606 and wafer bias voltage power source 616 can be configured to work with specific radio frequency, for example, work with 13.56 megahertz (MHz), 60MHz, 27MHz, 2MHz, 1MHz, 400 kilohertz (kHz) or their combination. Plasma power source 606 and wafer bias voltage power source 616 can be appropriately sized to provide a certain range of power to achieve desired processing performance. For example, in one embodiment, plasma power source 606 can provide power in the range of 50 to 5000 watts, and wafer bias voltage power source 616 can provide a bias voltage in the range of 20 to 2000V. In addition, TCP coil 610 and / or electrode 620 can include two or more sub-coils or sub-electrodes. The two or more sub-coils or sub-electrodes can be provided with power by a single power source or by multiple power sources.

[0047] like Figure 6As shown, the plasma processing system 600 also includes a gas source 630. The gas source 630 provides a gas or remote plasma to a feed 636 in the form of a nozzle. Process gases and byproducts are removed from the plasma processing chamber 604 via a pressure control valve 642 and a pump 644. The pressure control valve 642 and the pump 644 are also used to maintain a specific pressure within the plasma processing chamber 604. The gas source 630 is controlled by a controller 624. A controller 624 from Lam Research Corp. of Fremont, California may be used. To practice the embodiment. This embodiment is an inductively coupled plasma system. In other embodiments, a capacitively coupled plasma system can be used.

[0048] To provide an implementation of the controller 624 in one embodiment, Figure 7 624 is a high-level block diagram showing a computer system 700, which is suitable for implementing the controller 624 used in the embodiment. The computer system can have a variety of physical forms, ranging from integrated circuits, printed circuit boards, and small handheld devices to giant supercomputers. The computer system 700 includes one or more processors 702, and can further include an electronic display device 704 (for displaying graphics, text and other data), a main memory 706 (e.g., random access memory (RAM)), a storage device 708 (e.g., a hard disk drive), a removable storage device 710 (e.g., an optical drive), a user interface device 712 (e.g., a keyboard, a touch screen, a keypad, a mouse or other positioning devices, etc.) and a communication interface 714 (e.g., a wireless network interface). The communication interface 714 enables software and data to be transmitted between the computer system 700 and an external device through a link. The system can also include a communication infrastructure 716 (e.g., a communication bus, a cross-overbar, or a network) connected to the aforementioned device / module.

[0049] The information transmitted via the communication interface 714 may be in the form of a signal that can be received by the communication interface 714 through a communication link, such as an electronic, electromagnetic, optical, or other signal, which carries the signal and can be a communication link implemented using wires or cables, optical fibers, telephone lines, cellular phone links, radio frequency links, and / or other communication channels. Using such a communication interface, it is expected that one or more processors 702 can receive information from a network or can output information to a network during the implementation of the above-mentioned method steps. In addition, the method implementation can be executed only on the processor or can be executed in conjunction with a remote processor on a network such as the Internet, and the remote processor shares part of the processing.

[0050] The term "non-transitory computer-readable medium" is generally used to refer to media such as main memory, auxiliary memory, removable storage, and storage devices (such as hard disks, flash memory, hard drive memory, CD-ROMs, and other forms of permanent memory), and should not be interpreted as covering transient subject matter such as carrier waves or signals. Examples of computer code include machine code, such as that produced by a compiler, and files including higher-level code executed by a computer using an interpreter. Computer-readable media can also be computer code transmitted by a computer data signal embodied in a carrier wave and represented as a sequence of instructions executable by a processor.

[0051] Some embodiments allow for selective etching of features in the etch layer while the electrode 620 as a substrate support is maintained at a temperature below 400° C. In some embodiments, the substrate support is maintained at a temperature between 0° C. and 400° C. In some embodiments, the electrode 620 as a substrate support is maintained at a temperature below 300° C. For example, the electrode 620 as a substrate support is maintained at a temperature below 150° C. Maintaining the electrode 620 as a substrate support below 300° C. reduces thermal effects or thermal damage to the structure.

[0052] Although the present disclosure has been described according to several exemplary embodiments, there are changes, modifications, permutations and various alternative equivalents that fall within the scope of the present invention. It should also be noted that there are many alternatives to implement the method and apparatus of the present invention. Therefore, the following claims are intended to be interpreted as including all such changes, modifications, permutations and various alternative equivalents that fall within the true spirit and scope of the present invention. As used herein, the phrase "A, B or C" should be interpreted as representing the logic ("A or B or C") using a non-exclusive logic "OR", and should not be interpreted as representing "only" one of A or B or C. The various steps in the process may be selective and non-essential steps. Different embodiments may have one or more steps removed or the steps may be in different orders. In addition, various embodiments may provide different steps simultaneously rather than sequentially.

Claims

1. A method of selectively etching at least one feature in an etch layer of a doped or undoped material of at least one of silicon, silicon germanium, carbon and germanium relative to a mask, comprising: Simultaneously selectively etching at least one feature in the etch layer and selectively depositing a deposition layer relative to the mask, comprising: providing an etching gas comprising a precursor containing a metalloid or a metal and a component containing a halogen or oxygen; forming the etching gas into plasma; and The etch layer is exposed to the plasma to simultaneously etch at least one feature in the etch layer selectively relative to the mask and deposit a deposition layer of a metalloid or metal-containing material over the mask selectively relative to the etch layer.

2. The method according to claim 1, wherein the precursor containing a metalloid or a metal is a precursor containing a metalloid.

3. The method according to claim 1, wherein the precursor containing a metalloid or a metal is a precursor containing boron or silicon. 4 . The method of claim 1 , wherein the mask comprises at least one of silicon oxide or silicon nitride, and wherein the etch layer comprises at least one of silicon, silicon germanium, and germanium. 5 . The method according to claim 4 , further comprising a penetration etch for etching a native oxide layer on the etch layer.

6. The method according to claim 1, wherein the precursor containing a metalloid or a metal is a precursor containing at least one of boron, carbon, nitrogen, aluminum, hafnium, zirconium, tin, tantalum, molybdenum, tungsten, silicon, and oxygen.

7. The method of claim 1, wherein the halogen-containing component is at least one of BCl3, Cl2, HF, and HBr.

8. The method of claim 1 further comprising providing a pre-etch, wherein the pre-etch selectively and partially etches the etch layer relative to the mask prior to simultaneously selectively etching at least one feature in the etch layer relative to the mask and selectively depositing a deposition layer.

9. The method of claim 1, further comprising providing atomic layer etching of the at least one feature in the etch layer after simultaneously selectively etching the at least one feature in the etch layer relative to the mask and selectively depositing a deposition layer.

10. The method of claim 1, further comprising removing the deposited layer.

11. The method of claim 1 further comprising providing a substrate support temperature not exceeding 300°C.

12. The method of claim 1 , wherein the simultaneously selectively etching at least one feature in the etch layer and selectively depositing a deposition layer relative to the mask comprises: Selective deposition using at least one of PECVD, PEALD, and ALD and selective etching using at least one of RIE and ALE.

13. The method of claim 1, wherein the mask comprises a photoresist containing a metal, and wherein the etching layer comprises carbon.

14. The method of claim 1, wherein the deposited layer is at least one of an oxide, a nitride, and a carbide of a metal or metalloid.

15. The method of claim 1, wherein the etching layer comprises at least one of silicon, silicon germanium, and germanium, and wherein the etching gas comprises: Etching components containing halogens; and a deposition component including at least one of oxygen, carbon or nitrogen and at least one of a metal-containing precursor or a metalloid-containing precursor.

16. The method of claim 1, wherein the etching layer is carbon, and wherein the mask is a photoresist mask containing a metal, and wherein the etching gas comprises: An etching component containing oxygen; and a deposition component including a component containing at least one of oxygen, carbon or nitrogen and a precursor having a metal or containing at least one of a metalloid.

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