Simultaneous Dielectric Etching with Metal Passivation

Abstract

A method is provided for selectively etching at least one feature in a nitrogen-containing dielectric etch layer or a carbon-containing dielectric etch layer or a polysilicon etch layer under a mask in a stack while providing profile control and CD control. An etch gas including an etchant and a metal-containing passivant is flowed. The etch gas is plasmaized. The dielectric etch layer or the polysilicon etch layer is exposed to the plasma such that features are etched in the dielectric etch layer while a metal-containing passivation compound is deposited on sidewalls of the features.

Description

Background Art

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority of U.S. Application No. 63 / 341,568, filed May 13, 2022, which is hereby incorporated by reference in its entirety for all purposes.

[0002] The background art described herein is intended to generally present the content of the present disclosure. Information described in this background art section and aspects of the description that do not fall within the prior art at the time of filing are not admitted as prior art to the present disclosure, either expressly or impliedly.

[0003] The present disclosure relates to a method for forming semiconductor devices on a semiconductor wafer. In particular, the present disclosure relates to the selective etching of an etching layer with respect to a mask such as a hard mask.

[0004] The minimum feature size of semiconductor devices has been continuously shrinking in accordance with Moore's law. In the formation of narrow - width and high - aspect - ratio features, the features are etched into a nitrogen - containing layer, a carbon - containing layer, or a polysilicon layer. As the mask, silicon oxide (SiO) or photoresist may be used. Improving the etching selectivity enables a thinner mask, resulting in an improvement in resolution.

[0005] One of the processes commonly used in the fabrication of semiconductor devices is the formation of etched features. Examples of situations in which such a process may occur include, but are not limited to, memory applications. As the semiconductor industry advances and device dimensions are miniaturized, it becomes increasingly difficult to etch such features uniformly, particularly for high - aspect - ratio features having narrow widths and / or high depths.

[0006] Conventional processes for etching features in a dielectric layer use hydrocarbons, fluorocarbons, or hydrofluorocarbons to passivate the sidewalls of the features and control CD. The conventional process suffers from several problems, including a limited ability to control CD, mask profile, and mask topography as the CD of the feature shrinks. Depending on the application, such problems may be alleviated by high RF pulse capabilities, but typically result in a trade-off or compromise in the etching profile. SUMMARY OF THE INVENTION

[0007] In accordance with an object of the present disclosure, there is provided a method for selectively etching at least one feature in a nitrogen-containing dielectric etch layer or a carbon-containing dielectric etch layer or a polysilicon etch layer under a mask of a stack while providing profile control and CD control. An etching gas including an etchant and a metal-containing passivant is flowed. The etching gas is plasmaized. The dielectric etch layer or the polysilicon etch layer is exposed to the plasma such that a feature is etched in the dielectric etch layer while a metal-containing passivation film is deposited on the sidewalls of the feature.

[0008] These and other features of the present disclosure will be described in more detail in the following detailed description of the invention and in conjunction with the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present disclosure is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals mean like elements.

[0010]

Figure 1

[0011]

Figure 2A

Figure 2B

Figure 2C

[0012]

Figure 3A

Figure 3B

Figure 3C

Figure 3D

[0013]

Figure 4

[0014]

Figure 5

[0015] Here, the present disclosure will be described in detail with reference to some exemplary embodiments thereof, as shown in the accompanying drawings. In the following description, several specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the embodiments of the present disclosure may be practiced without some or all of these specific details. In other instances, well-known process steps and / or structures have not been described in detail so as not to obscure the present disclosure unnecessarily.

[0016] In the formation of semiconductor devices, one or more dielectric layers may be etched. In some embodiments, the stack includes one or more carbon-containing or nitrogen-containing layers (e.g., one or more layers of silicon carbide (SiC), silicon nitride (SiN), silicon oxynitride (SiON), amorphous carbon, and photoresist). In some embodiments, the polysilicon layer within the stack is etched. Conventional processes for etching features in dielectric layers passivate the sidewalls of the features using hydrocarbons, fluorocarbons, or hydrofluorocarbons to control the CD. As the CD of the features shrinks, conventional processes are plagued by several problems, including limited ability to control the CD, mask profile, and mask shape. Depending on the application, such problems may be alleviated by high RF pulse capabilities, but generally result in a trade-off or compromise in the etching profile. When hydrocarbons, fluorocarbons, or hydrofluorocarbons are used for passivation to etch a silicon nitride or silicon carbide layer under a silicon mask or carbon-containing mask, passivation deposits near the openings of the polysilicon mask, causing necking. If there is too much passivation deposit near the openings of the polysilicon mask, the etched features may become tapered or the deposits may cause an etch stop. Necking causes changes in the etching rate and CD, making it more difficult to control the etching rate and CD. Various parameters such as power, pressure, bias, gas flow, and gas ratio may be used to reduce tapering and etch stop and control the aspect ratio. However, adjusting such parameters may affect the bowing of the etched features, etching selectivity, CD, and other characteristics.

[0017] Some embodiments provide for etching a stack, and in so doing, provide passivation of metal-containing sidewalls, to etch a stack that includes one or more carbon-containing dielectric etch layers or nitrogen-containing dielectric etch layers or polysilicon etch layers. In some embodiments, the stack may include one or more of silicon nitride, silicon carbide, silicon carbonitride (SiCN), silicon oxynitride, amorphous carbon, polysilicon, and photoresist.

[0018] FIG. 1 is a high-level flowchart of a process used in some embodiments for ease of understanding. A structure is provided in an etching chamber (step 104). In some embodiments, the structure includes a stack of one or more nitrogen-containing dielectric layers or carbon-containing dielectric layers. In some embodiments, the nitrogen-containing dielectric layer or carbon-containing dielectric layer may be one or more of silicon carbide, silicon nitride, silicon oxynitride, amorphous carbon, and photoresist. In some embodiments, the structure includes a polysilicon layer.

[0019] The stack is etched in the etching chamber. To etch the stack, an etching gas including an etchant and a metal-containing passivant is provided (step 108). In some embodiments, the etchant is an oxygen-containing component or a halogen-containing component. In some embodiments, the oxygen-containing component includes at least one of oxygen (O 2 ), ozone (O 3 ), carbon dioxide (CO 2 ), carbon monoxide (CO), carbonyl sulfide (COS), nitrogen dioxide (NO 2 ), nitrate (NO 3 ), and sulfur dioxide (SO 2 ). In some embodiments, the halogen-containing component is a hydrofluorocarbon (C x H y F z )(e.g., fluoromethane (CH 3 F), difluoromethane (CH 2 F 2 ), and fluoroform (CHF 3)) fluorocarbon (C x F y )(e.g., carbon tetrafluoride (CF 4 ), octafluorocyclobutane (C 4 F 8 ), and hexafluorobutadiene (C 4 F 6 )) hydrogen bromide (HBr), hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen iodide (HI), boron trichloride (BCl 3 ), and chlorine (Cl 2 ). Generally, the etching gas has a lean chemistry that minimizes polymer deposition to prevent necking. In various embodiments, the halogen-containing component includes at least one of a fluorocarbon (e.g., carbon tetrafluoride), hexafluorobutadiene, octafluorocyclobutane, and fluorinated hydrocarbon.

[0020] In some embodiments, the metal-containing passivant includes a component including at least one of molybdenum (Mo), rhenium (Re), tantalum (Ta), tungsten (W), or vanadium (V). For example, the metal-containing passivant includes at least one of rhenium hexafluoride (ReF 6 ), molybdenum hexafluoride (MoF 6 ), tantalum pentafluoride (TaF 5 ), tungsten hexafluoride (WF 6 ), and vanadium fluoride (VF 5 ). In some embodiments, the etching gas further includes an inert diluent. In some embodiments, the inert diluent is one or more noble gases (e.g., helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe)).

[0021] The etching gas is plasma - ized (step 112). In some embodiments, RF excitation power is provided to plasma - ize the etching gas. The RF power may be provided at various frequencies. In various embodiments, the RF power is provided at at least one of the frequencies of 13.56 megahertz (MHz), 60 MHz, 27 MHz, 2 MHz, 1 MHz, and 400 kilohertz (kHz).

[0022] The plasma is used to etch the stack to form an etching feature and provide metal passivation of the sidewalls of the etching feature (step 116). The etchant in the plasma etches the etching layer such that the etching feature is etched into the etching layer. The metal passivant forms a metal passivation layer on the sidewalls of the etching feature. In some embodiments, a bias is applied to provide more directional etching.

[0023] In some embodiments, a post - etching process is provided as needed (120). In some embodiments, the post - etching is a chemical etching used to remove the metal - containing passivation layer. In some embodiments, the post - etching process etches a layer below the etching layer and then the etching layer is removed together with the metal - containing passivation layer.

[0024] The metal passivation layer has been found to have better etching resistance than polymer passivation. Therefore, some embodiments provide passivation with better etching resistance than processes using polymer passivation. Also, the metal passivation layer has been found to be more resistant to ion collisions than polymer passivation. Therefore, etching features with a metal passivation layer are less affected by bowing. Therefore, tuning may be optimized for etching selectivity and CD without optimization for bowing reduction. Further, by providing both an etchant and a metal-containing passivant in the etching gas, a stronger process is provided that enables optimization to eliminate etch stops. In some embodiments, some of the metal passivation layer may be deposited on the etch front. Sufficient bias power is provided to prevent etch stops, removing all of the metal passivation layer on the etch front. Providing an etching gas without a metal-containing passivant and having another passivation step with a metal-containing passivant has been found to result in a less robust method that increases the likelihood of causing an etch stop.

[0025] Example 1 In some embodiments, in providing a structure having a dielectric etch layer under the mask (step 104), an etch layer of silicon nitride or silicon carbide is provided under the polysilicon mask. In this example, this structure may be used for etching capacitors. FIG. 2A is a schematic cross-sectional view of a portion of a structure 200 having a stack of a single etch layer 204 of silicon nitride under a polysilicon mask 208 on a substrate 202 such as a wafer. The mask 208 is a patterned formation mask feature 212. There may be one or more layers between the substrate 202 and the single etch layer 204. The structure 200 is placed in an etch chamber (step 104).

[0026] An etching gas containing an etchant and a passivant is flowed into an etching chamber (step 108). In this example, the etchant includes a hydrofluorocarbon such as trifluoromethane, and the passivant includes tungsten hexafluoride. In some embodiments, the etching gas further includes an inert diluent. In some embodiments, the inert diluent is one or more noble gases. The etching gas provides a pressure in the range of 5 mTorr to 400 mTorr.

[0027] The etching gas is plasmaized (step 112). In this example, RF power is provided at one or more frequencies of 400 kHz, 2 MHz, 27 MHz, and 60 MHz. The RF power may be used to provide a bias in addition to exciting the plasma. The amount of bias depends on its application. A high bias is used for high aspect ratio features. Since high aspect ratio features are used for this application, a high bias is provided. Also, in applications where etch stop is likely to occur, a high bias is used to prevent etch stop.

[0028] The stack is exposed to plasma. The plasma selectively etches the etching features in the etching layer 204 and deposits a metal-containing passivation compound on the sidewalls of the etching features (step 116). FIG. 2B is a schematic cross-sectional view of a portion of the structure 200 after the etching feature 220 has been partially etched. The metal-containing passivation layer 224 is deposited on the sidewalls of the etching feature 220. For clarity of illustration, the metal-containing passivation layer 224 is not drawn to scale. In this example, the metal-containing passivation layer includes tungsten nitride, where tungsten is provided by tungsten hexafluoride and nitrogen is provided by the silicon nitride etching layer 204. Instead of providing the passivant without an etchant at some point, by providing the etchant and the metal-containing passivant simultaneously, the metal-containing passivation layer 224 is not formed at the etch front so as to avoid etch stop. In some embodiments, some of the metal passivation layer may be deposited at the etch front. Sufficient bias power is provided to prevent etch stop and remove all metal passivation layers at the etch front. Also, the simultaneous etching and deposition of the metal passivation layer provides a high-speed etching process and high throughput. Further, various etching parameters (such as pressure, RF power, bias power, and gas flow rate) may be adjusted such that the metal-containing passivation layer 224 is deposited at the sidewall location of the etching feature 220 that will be most affected by bowing, while removing or preventing metal passivation compounds at other locations of the etching feature. Some embodiments provide for the simultaneous etching and formation of the metal-containing passivation layer while preventing etch stop and controlling CD.

[0029] FIG. 2C is a schematic cross-sectional view of the structure 200 after the etching of the etching feature 220 is completed. In this embodiment, the metal-containing passivation layer is removed during the etching process. In other embodiments, subsequent processes may be used to remove the metal-containing passivation layer. In some embodiments, the flow rate of the passivant is reduced near the end of the etching process so that there is no or little metal-containing passivation layer remaining at the end of the etching process.

[0030] In some embodiments, a post-etching process (step 120) is provided as needed to remove all remaining metal-containing passivation layers. An example of a post-etching process for removing the remaining metal-containing passivation layer uses a post-etching process gas containing fluorocarbon and oxygen. In some embodiments, the post-etching process further etches or shapes the etching feature as needed. Examples of processes for further etching and / or shaping the feature are SiO 2 using a post-etching process gas containing fluorocarbon and oxygen to etch the underlying layer. In some embodiments, the feature has a CD of 40 nm or less and an aspect ratio of height to width of at least 6:1.

[0031] Example 2 In some embodiments, in providing a structure having a dielectric etch layer under a mask (step 104), a carbon-containing (e.g., amorphous carbon) etch layer is provided under a bottom anti-reflective coating (BARC). The BARC is formed of a material containing silicon and nitrogen or carbon (such as silicon nitride, silicon oxynitride, and silicon carbide) under a photoresist mask in an etching chamber in some embodiments. In some embodiments, the carbon-containing layer is a carbon-based layer (e.g., amorphous carbon). In this specification and the claims, a carbon-based material is at least 50 wt% carbon. FIG. 3A is a schematic cross-sectional view of a portion of a structure 300, which includes a stack having a BARC layer 307 under a photoresist mask 308, an amorphous carbon etch layer 306 thereunder, a lower layer 304 thereunder, and a substrate 302 thereunder. The mask 308 is a patterned formation mask feature 312. The structure 300 is provided in an etching chamber (step 104).

[0032] To open the BARC 307, an etching gas containing an etchant and a passivant is flowed into the etching chamber (step 108). In this example, the etchant includes a halogen-containing component and the passivant includes tungsten hexafluoride. In some embodiments, the etching gas further includes an inert diluent. In some embodiments, the inert diluent is one or more noble gases. The etching gas provides a pressure in the range of 5 mTorr to 500 mTorr.

[0033] The etching gas is plasmaized (step 112). In this example, RF power is provided at one or more frequencies of 400 kHz, 2 MHz, 27 MHz, and 60 MHz. The RF power may be used to provide a bias in addition to exciting the plasma. The amount of bias depends on the application. A high bias is used for high aspect ratio features. Also, in applications where etch stop is likely to occur, a high bias is used to prevent etch stop. Since this embodiment is for opening the BARC, the features are not high aspect ratio features.

[0034] The stack is exposed to plasma. The plasma selectively etches the etching features in the BARC 307 and deposits a metal-containing passivation compound on the sidewalls of the etching features (step 116). The metal-containing passivation layer is deposited on the sidewalls of the etching features. In this example, the metal-containing passivation layer includes tungsten carbide and / or tungsten nitride, where tungsten is provided by tungsten hexafluoride and carbon or nitrogen is provided by the BARC 307. Sufficient bias power is provided to prevent etch stop, removing all metal passivation layers at the etch front. Also, various etching parameters (such as pressure, RF power, bias power, and gas flow rate) may be adjusted such that the metal-containing passivation layer is deposited at the sidewall positions of the etching features that will be most affected by the bowing, while removing or preventing metal passivation compounds at other positions of the etching features.

[0035] To open the amorphous carbon etch layer 306, an etching gas containing an etchant and a passivant is flowed into the etching chamber (step 108). In this example, the etchant includes an oxygen-containing component and the passivant includes tungsten hexafluoride. In some embodiments, the etching gas further includes an inert diluent. In some embodiments, the inert diluent is one or more noble gases. In some embodiments, the oxygen-containing component includes at least one of oxygen, ozone, carbon dioxide, carbon monoxide, carbonyl sulfide, nitrogen dioxide, nitrates, and sulfur dioxide. The etching gas provides a pressure in the range of 5 mTorr to 500 mTorr.

[0036] The etching gas is plasma - ized (step 112). In this embodiment, RF power is provided at one or more frequencies of 400 kHz, 2 MHz, 27 MHz, and 60 MHz. The RF power may be used to provide a bias in addition to exciting the plasma. The amount of bias depends on its application. A high bias is used for high aspect - ratio features. Also, in applications where an etch stop is likely to occur, a high bias is used to prevent the etch stop. Since this embodiment is for opening a mask, the features are not high aspect - ratio features.

[0037] The stack is exposed to the plasma. The plasma selectively etches the etching features in the etching layer and deposits a metal - containing passivation layer on the sidewalls of the etching features (step 116). The metal - containing passivation layer is deposited on the sidewalls of the etching features. In this example, the metal - containing passivation layer contains tungsten carbide, where tungsten is provided by tungsten hexafluoride and carbon is provided by the amorphous carbon etching layer 306. Instead of providing a passivant without an etchant at some point, by providing the etchant and the metal - containing passivant simultaneously, the metal - containing passivation layer is not formed at the etch front so that the etch stop is avoided. In some embodiments, some of the metal passivation layer may be deposited at the etch front. Sufficient bias power is provided to prevent the etch stop so that all the metal passivation layers on the etch front are removed. Also, various etching parameters (such as pressure, RF power, bias power, and gas flow rate) may be adjusted so that the metal - containing passivation layer is deposited at the sidewall position of the etching feature that will be most affected by bowing, while removing or preventing metal passivation at other positions of the etching feature.

[0038] Figure 3B is a schematic cross-sectional view of structure 300 after etching feature 320 has been etched into BARC 307 and amorphous carbon etch layer 306. In this embodiment, the metal-containing passivation layer is removed during the etching process. In other embodiments, a subsequent process may be used to remove the metal-containing passivation layer.

[0039] In some embodiments, a post-etching process (120) is provided as needed. In this example, the underlying layer 304 is a silicon-containing layer below the amorphous carbon etch layer 306. In this example, the amorphous carbon etch layer 306 is used as a mask for etching the silicon-containing underlying layer 304.

[0040] Figure 3C is a schematic cross-sectional view of structure 300 after etching feature 324 has been etched into the underlying layer 304. The pattern formed by the amorphous carbon layer 306 has been transferred to the underlying layer 304. In this example, the etching of the silicon-containing underlying layer 304 etches the mask and the BARC.

[0041] In some embodiments, the post-etching process (step 120) may further include one or more processes to remove the amorphous carbon etch layer 306. Such processes may also remove all remaining metal-containing passivation layers. Figure 3D is a schematic cross-sectional view of structure 300 after the amorphous carbon etch layer 306 shown in Figure 3C has been removed. In some embodiments, the metal-containing passivation layer is removed simultaneously with the removal of the amorphous carbon etch layer 306.

[0042] Various embodiments In some embodiments, the stack may be a single layer of a nitrogen-containing layer or a carbon-containing layer (e.g., a single layer of silicon nitride or amorphous carbon). In some embodiments, the stack may be a plurality of layers in which at least one layer is a nitrogen-containing layer or a carbon-containing layer. For example, the stack may be an alternating layer stack of silicon nitride and silicon oxide (ONON). In some embodiments, the requirement that the etching layer contains nitrogen or carbon is such that the metal-containing passivant requires a sufficient amount of nitrogen or carbon so that a passivation layer of metal nitride or metal carbide can be formed on the sidewalls of the feature. Since the passivation layer of metal nitride or metal carbide has high resistance to chemical etching and ion bombardment, the passivation layer of metal nitride or metal carbide reduces the bowing and CD increase caused by sidewall etching. As a result, in some embodiments, etching parameters such as pressure, RF power, RF bias, and temperature may be adjusted to optimize other etching characteristics (e.g., selectivity, aspect ratio, density vs. spacer fill, profile control, CD control, and tapering). In some embodiments, the bias is adjusted to adjust the aspect ratio. Also, in some embodiments, the etching parameters are more robust and allow for a wider parameter window.

[0043] In some embodiments, the metal-containing passivant includes tungsten. In such embodiments, the passivation layer includes tungsten carbide or tungsten nitride, and the carbon or nitrogen is provided by a nitrogen-containing etching layer or a carbon-containing etching layer. In some embodiments, the nitrogen-containing etching layer or the carbon-containing etching layer further includes silicon. In some embodiments, the carbon-containing etching layer is a carbon-based etching layer such as amorphous carbon and photoresist.

[0044] Some embodiments can not only avoid an increase in CD, but also adjust the CD. The CD of the carbon-containing layer or the nitrogen-containing layer may be adjusted by controlling the metal-containing gas flow without compromising the shape of the mask.

[0045] In some embodiments, the etching process may be used to provide etching of the capacitor. In some embodiments, the etching process may be used in the formation of a dynamic random access memory. In some embodiments, when the etching layer is a polysilicon layer and the passivant is tungsten hexafluoride, the tungsten element deposits as a passivation layer on the sidewalls of the polysilicon layer rather than tungsten carbide or tungsten nitride (when nitrogen and carbon are not present during the etching process). In some embodiments, the flow rates of the different components of the etching gas may be changed during the process.

[0046] Device FIG. 4 is a schematic diagram of a plasma processing chamber 400 for a plasma processing substrate in an embodiment for ease of understanding. In one or more embodiments, the plasma processing chamber 400 includes a gas distribution plate 406 that provides a gas inlet and an electrostatic chuck (ESC) 416 inside a plasma processing chamber 404 surrounded by a chamber wall 450. Inside the plasma processing chamber 404, a substrate 202 is placed on the ESC 416 that functions as a substrate support. The ESC 416 may provide a bias from an ESC power supply 448. A gas source 410 is connected to the plasma processing chamber 404 via the gas distribution plate 406. An ESC temperature controller 451 is connected to the ESC 416 and provides temperature control of the ESC 416. A radio frequency (RF) power supply 430 provides RF power to the ESC 416 and an upper electrode. In this embodiment, the upper electrode is the gas distribution plate 406. In a preferred embodiment, power supplies of 400 kilohertz (kHz), 13.56 megahertz (MHz), 1 MHz, 2 MHz, 60 MHz, and / or 27 MHz as required constitute the RF power supply 430 and the ESC power supply 448. A controller 435 is controllably connected to the RF power supply 430, the ESC power supply 448, an exhaust pump 420, and the gas source 410. A high flow rate liner 460 is a liner inside the plasma processing chamber 404, confines the gas from the gas source, and has slots 462. The slots 462 maintain a controlled gas flow from the gas source 410 to the exhaust pump 420. An example of such a plasma processing chamber is a Flex® etching system manufactured by Lam Research Corporation of Fremont, California. The process chamber may be a CCP (capacitively coupled plasma) reactor or an ICP (inductively coupled plasma) reactor.

[0047] FIG. 5 is a high-level block diagram showing a computer system 500 for implementing a controller 435 used in an embodiment of the present invention. The computer system can have many physical forms, ranging from integrated circuits, printed circuit boards, and small handheld devices to large supercomputers. The computer system 500 may include one or more processors 502, and further, a display device 504 (for displaying drawings, text, and other data), a main memory 506 (e.g., random access memory (RAM)), a storage device 508 (e.g., hard disk drive), a removable storage device 510 (e.g., optical disk drive), a user interface device 512 (e.g., keyboard, touch screen, keypad, mouse, or other pointing device, etc.), and / or a communication interface 514 (e.g., wireless network interface). The communication interface 514 may enable software and / or data to be transferred between the computer system 500 and an external device via a link. The system may include a communication infrastructure 516 (e.g., communication bus, crossover bar, or network) to which the above devices / modules can be connected.

[0048] The information transferred through the communication interface 514 may be in the form of signals (electronic signals, electromagnetic signals, optical signals, or other signals that can be received by the communication interface 514 via a communication link that carries the signal), and may be implemented using wires or cables, optical fibers, telephone lines, cellular phone links, radio frequency links, and / or other communication lines. It is contemplated that one or more processors 502 can receive information from a network or output information to a network by such a communication interface in the process of implementing the above method steps. Further, embodiments of the method may be executed alone on a processor or may be executed on a network such as the Internet together with a remote processor that shares part of the processing.

[0049] The term "non-transitory computer-readable medium" is generally used to refer to media such as main memory, secondary memory, removable storage, and storage devices (e.g., hard disks, flash memories, disk drive memories, CD-ROMs, and other forms of persistent memory), and is not construed to include transitory entities such as carrier waves or signals. Examples of computer code include machine code generated by a compiler and files containing high-level code that is executed by a computer using an interpreter. A computer-readable medium may also be computer code embodied in a carrier wave and transmitted by a computer data signal representing an array of instructions executable by a processor.

[0050] Although the present disclosure has been described in terms of some exemplary embodiments, there are changes, modifications, substitutions, and various alternative equivalents that fall within the scope of the present disclosure. It should also be noted that there are many other ways of implementing the methods and apparatuses of the present disclosure. Therefore, the following appended claims are intended to be construed to include such changes, modifications, substitutions, and various alternative equivalents that fall within the true spirit and scope of the present disclosure. As used herein, the expression "A, B, or C" is construed to mean a logic using non-exclusive logical "OR" ("A OR B OR C") and is not construed to mean "only one of A or B or C". Each step of a process is optional and not essential. Different embodiments may exclude one or more steps or may provide steps in a different order. Also, various embodiments may provide different steps simultaneously rather than sequentially.

Claims

1. A method for selectively etching at least one feature in a nitrogen-containing dielectric etch layer or a carbon-containing dielectric etch layer or a polysilicon etch layer under a mask in a stack while providing profile control and CD control, comprising: flowing an etchant gas comprising an etchant and a metal-containing passivant; plasmaizing the etchant gas; exposing the dielectric etch layer or the polysilicon etch layer to the plasma to etch a feature in the dielectric etch layer while depositing a metal-containing passivation film on the sidewalls of the feature; A method comprising the above steps.

2. The method according to claim 1, wherein the etchant comprises at least one of a halogen-containing component and an oxygen-containing component.

3. The method according to claim 1, wherein the metal-containing passivant comprises a component containing at least one of molybdenum, rhenium, tantalum, tungsten, and vanadium.

4. The method according to claim 1, wherein the mask is a silicon-containing mask or a carbon-containing mask.

5. The method according to claim 1, wherein the nitrogen-containing dielectric layer or the carbon-containing dielectric layer contains silicon, and the etchant contains a halogen-containing component.

6. The method according to claim 5, wherein the halogen-containing component comprises at least one of a hydrofluorocarbon and a fluorocarbon.

7. The method according to claim 1, further comprising controlling the aspect ratio using RF excitation power and bias power.

8. The method according to claim 1, wherein the metal-containing passivant comprises at least one of tungsten hexafluoride, rhenium hexafluoride, molybdenum hexafluoride, tantalum pentafluoride, and vanadium fluoride.

9. The method according to claim 1, further comprising chemically removing the metal-containing passivation film.

10. The method according to claim 1, wherein the dielectric etch layer or the polysilicon etch layer is on top of a lower layer, and the method further comprises etching the lower layer.

11. The method according to claim 10, further comprising A method including a step of removing the dielectric etching layer or the polysilicon etching layer.

12. The method according to claim 11, wherein the step of removing the dielectric etching layer or the polysilicon etching layer removes the metal-containing passivation compound.

13. The method according to claim 1, wherein the nitrogen-containing dielectric layer or the carbon-containing dielectric layer includes an amorphous carbon layer or a carbon-based layer, and the etchant includes an oxygen-containing etchant.

14. The method according to claim 13, wherein the oxygen-containing etching includes at least one of oxygen, ozone, carbon dioxide, carbon monoxide, carbonyl sulfide, nitrogen dioxide, nitrate, and sulfur dioxide.

15. The method according to claim 1, wherein the nitrogen-containing dielectric etching layer or the carbon-containing dielectric etching layer or the polysilicon etching layer is a nitrogen-containing dielectric etching layer or a carbon-containing dielectric etching layer, the metal-containing passivation compound includes a metal carbide or a metal nitride, and the carbon of the metal carbide or the nitrogen of the metal nitride is provided by the nitrogen-containing dielectric etching layer or the carbon-containing dielectric etching layer.

Images