Simultaneous dielectric etch and metal passivation

Abstract

A method of selectively etching at least one feature of a nitrogen or carbon containing dielectric etch layer or polysilicon etch layer under a mask in a stack while providing both profile control and CD control is provided. An etching gas including an etchant and a metal-containing deactivator is flowed. The etching gas is formed into a plasma. The dielectric etch layer or polysilicon etch layer is exposed to a plasma to simultaneously etch features into the dielectric etch layer and deposit metal-containing passivation on sidewalls of the features.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Application No. 63 / 341,568, filed on May 13, 2022, which is hereby incorporated by reference for all purposes. Background Art

[0002] The background description provided herein is to generally present the context of the present disclosure. The information described in this background section and all aspects of the specification that may not qualify as prior art at the time of filing are not explicitly or 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 is shrinking in accordance with Moore's Law. When forming features with small widths and high aspect ratios, nitrogen or carbon containing layers or polysilicon layers are etched. Silicon oxide (SiO) or photoresist can be used as a mask. Improved etch selectivity allows the use of thinner masks, thereby improving resolution.

[0005] One process that is often employed during the fabrication of semiconductor devices is the formation of etched features. Example contexts in which such processes may be performed include, but are not limited to, memory applications. As the semiconductor industry advances and device dimensions continue to shrink, these features become increasingly difficult to etch in a uniform manner, particularly for high aspect ratio features with narrow widths and / or high depths.

[0006] Traditional processes for etching dielectric layer features use hydrocarbons, fluorocarbons, or hydrofluorocarbons to passivate feature sidewalls and control CD. As feature CD shrinks, traditional processes face multiple issues, including limited ability to control CD, mask profile, and mask morphology. Depending on the application, these issues can sometimes be mitigated with advanced RF pulsing capabilities. However, this often results in damage or compromised etch profiles. Summary of the invention

[0007] To achieve the above objectives and in accordance with the purpose of the present disclosure, a method is provided for selectively etching at least one feature in a nitrogen or carbon containing dielectric etch layer or a polysilicon etch layer below a mask in a stack while providing profile control and CD control. An etching gas including an etchant and a metal containing passivating agent is flowed. The etching gas is formed into a plasma. The dielectric etch layer or the polysilicon etch layer is exposed to the plasma to simultaneously etch a feature into the dielectric etch layer and deposit a metal containing passivating agent 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 and in conjunction with the accompanying figures. 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 refer to similar elements and in which:

[0010] Figure 1 is a high-level flow chart of an implementation scheme.

[0011] FIG. 2A to FIG. 2C is a schematic cross-sectional view of a structure processed according to some embodiments.

[0012] FIG. 3A to FIG. 3D is a schematic cross-sectional view of a structure processed according to some embodiments.

[0013] Figure 4 is a schematic diagram of an etch chamber that may be used in one embodiment.

[0014] Figure 5 is a schematic diagram of a computer system that can be used to practice one embodiment. DETAILED DESCRIPTION

[0015] The present disclosure 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 disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without some or all of these specific details. In other cases, well-known process steps and / or structures are not described in detail to avoid unnecessarily obscuring the present disclosure.

[0016] During the formation of a semiconductor device, a stack having one or more dielectric layers can be etched. In some embodiments, the stack includes one or more carbon or nitrogen-containing layers, such as one or more silicon carbide (SiC), silicon nitride (SiN), silicon oxynitride (SiON), amorphous carbon, and a photoresist layer. In some embodiments, a polysilicon layer in the stack is etched. Conventional processes for etching dielectric layer features use hydrocarbons, fluorocarbons, or hydrofluorocarbons to passivate feature sidewalls and control CD. As feature CDs shrink, conventional processes face multiple problems, including limited ability to control CD, mask profiles, and mask morphology. Depending on the application, such problems can sometimes be alleviated by advanced RF pulse capabilities. However, this often results in damage or compromise of the etching profile. In order to etch a silicon nitride layer or silicon carbide layer under a silicon mask or a carbon-containing mask, when passivation is performed using hydrocarbons, fluorocarbons, or hydrofluorocarbons, the passivation is deposited near the opening of the polysilicon mask, causing necking. When too much passivation accumulates near the opening of the polysilicon mask, the etched features may taper, or the accumulation may cause etch stop. Necking causes changes in etch rate and CD, making etch rate control and CD control more difficult. Various parameters such as power, pressure, bias, gas flow, and gas ratio can be used to reduce taper and etch stop and control aspect ratio. However, adjustment of such parameters affects bowing, etch selectivity, CD, and other characteristics of etched features.

[0017] Some embodiments provide etching of a stack including one or more carbon or nitrogen containing dielectric etch layers or polysilicon etch layers by simultaneously etching the stack and providing metal containing sidewall passivation. 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] For ease of understanding, Figure 1 1 is a high level flow chart of a process used in some embodiments. The structure is placed in an etching chamber (step 104). In some embodiments, the structure includes a stack of one or more dielectric layers containing nitrogen or carbon. In some embodiments, the dielectric layer containing nitrogen or carbon can 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 an etching chamber. To etch the stack, an etching gas comprising an etchant and a metal-containing passivating agent 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 oxygen (O 2 ), ozone (O 3 ), carbon dioxide (CO 2), carbon monoxide (CO), carbonyl sulfide (COS), nitrogen dioxide (NO 2 ), nitrate (NO 3 ), sulfur dioxide (SO 2 In some embodiments, the halogen-containing component includes at least one of the following: hydrofluorocarbon (C x H y F z ), such as fluoromethane (CH 3 F), difluoromethane (CH 2 F 2 ) and trifluoromethane (CHF 3 );Fluorocarbon (C x F y ), such as carbon tetrafluoride (CF 4 ), octafluorocyclobutane (C 4 F 8 ) and hexafluorobutadiene (C 4 F 6 ); hydrogen bromide (HBr), hydrogen fluoride (HF), hydrogen chloride (HC1), hydrogen iodide (HI), boron trichloride (BCl 3 ) and chlorine (Cl 2 ). Generally, the etching gas has a dilute chemistry to minimize polymer deposition, thereby preventing necking. In various embodiments, the halogen-containing component includes at least one of a fluorocarbon compound, such as carbon tetrafluoride, hexafluorobutadiene, octafluorocyclobutane, and a fluorocarbon.

[0020] In some embodiments, the metal-containing passivating agent comprises a component containing at least one of molybdenum (Mo), rhenium (Re), tantalum (Ta), tungsten (W), or vanadium (V). For example, the metal-containing passivating agent comprises 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 comprises an inert diluent. In some embodiments, the inert diluent is one or more rare gases, such as helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe).

[0021] The etching gas is formed into a plasma (step 112). In some embodiments, RF excitation power is provided to convert the etching gas into a plasma. The RF power can be provided at a variety of frequencies. In various embodiments, the RF power is provided at at least one of the following frequencies: 13.56 megahertz (MHz), 60 MHz, 27 MHz, 2 MHz, 1 MHz, and 400 kilohertz (kHz).

[0022] The stack is etched using plasma to form etched features and provide metal passivation of the sidewalls of the etched features (step 116). The etchant in the plasma etches the etch layer, thereby etching the etched features into the etch layer. The metal passivator forms a metal passivation layer on the sidewalls of the etched features. In some embodiments, a bias voltage is provided to provide a more directional etch.

[0023] In some embodiments, an optional post-etching process (120) is provided. In some embodiments, the post-etching is a chemical etch for removing the metal-containing passivation layer. In some embodiments, the post-etching process etches the layer below the etch layer and then removes the etch layer along with the metal-containing passivation layer.

[0024] It has been found that metal passivation layers are more etch-resistant than polymer passivation. Therefore, some embodiments provide a passivation that is more etch-resistant than a process using polymer passivation. In addition, it has been found that metal passivation layers are more resistant to ion bombardment than polymer passivation. Therefore, etching features with metal passivation layers are less prone to bending. Therefore, it can be optimized for etching selectivity and CD without optimizing for the reduction of bending. In addition, it has been found that providing both an etchant and a metal-containing passivator in an etching gas provides a more robust process, thereby achieving optimization that helps to eliminate etching stops. In some embodiments, some metal passivation layers can be deposited on the etching front. In order to prevent etching from stopping, it is necessary to provide sufficient bias power to remove any metal passivation layer on the etching front. It has been found that providing an etching gas without a metal-containing passivator and adopting a separate passivation step containing a metal passivator causes the method to be not robust enough, thereby increasing the possibility of causing etching to stop. Example 1

[0025] In some embodiments, a structure having a dielectric etch layer is provided under a mask (step 104). A silicon nitride or silicon carbide etch layer is provided under a polysilicon mask. In this embodiment, the structure can be used for capacitor etching. Figure 2A2 is a schematic cross-sectional view of a portion of a structure 200 in which a single etch layer 204 of silicon nitride is stacked above a substrate 202 (e.g., a wafer) and below a polysilicon mask 208. The mask 208 is patterned to form mask features 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 etching chamber (step 104).

[0026] An etching gas containing an etchant and a passivating agent is flowed into the etching chamber (step 108). In the present embodiment, the etchant comprises a hydrofluorocarbon, such as trifluoromethane, and the passivating agent comprises tungsten hexafluoride. In some embodiments, the etching gas further comprises an inert diluent. In some embodiments, the inert diluent is one or more rare gases. The pressure provided by the etching gas ranges from 5 mTorr to 400 mTorr.

[0027] The etching gas is converted to plasma (step 112). In the present embodiment, RF power is provided at one or more frequencies of 400kHz, 2MHz, 27MHz and 60MHz. In addition to plasma excitation, RF power can also be used to provide a bias voltage. The amount of bias voltage depends on the application. For higher aspect ratio features, a higher bias voltage is used. Since the application has a higher aspect ratio feature, a higher bias voltage is provided. In addition, in the case of an application where etch stop is more likely to occur, a higher bias voltage is used to prevent etch stop.

[0028] The stack is exposed to a plasma. The plasma selectively etches the etched features in the etch layer 204 and deposits a metal-containing passivation on the sidewalls of the etched features (step 116). Figure 2B2 is a schematic cross-sectional view of a portion of structure 200 after etch feature 220 has been partially etched. A metal-containing passivation layer 224 has been deposited on the sidewalls of etch feature 220. To more clearly show the metal-containing passivation layer 224, the metal-containing passivation layer 224 is not drawn to scale. In this embodiment, the metal-containing passivation layer includes tungsten nitride, wherein the tungsten is provided by tungsten hexafluoride and the nitrogen is provided by silicon nitride etch layer 204. By providing an etchant and a metal-containing passivator simultaneously, rather than providing a passivator at certain times without providing an etchant, the metal-containing passivation layer 224 is not formed at the etch front end, thereby avoiding etch stop. In some embodiments, some metal passivation layers may be deposited on the etch front end. To prevent etch stop, sufficient bias power is provided to remove any metal passivation layer on the etch front end. In addition, etching and depositing the metal passivation layer simultaneously provides a faster etching process and faster production capacity. In addition, various etching parameters, such as pressure, RF power, bias power, and gas flow rates, can be adjusted to deposit the metal-containing passivation layer 224 at locations on the sidewalls of the etched features 220 that will be most susceptible to bending while removing or preventing metal passivation at other locations in the etched features. Some embodiments provide for simultaneous etching and formation of the metal-containing passivation layer while preventing etch stop and controlling CD.

[0029] Figure 2C 2 is a schematic cross-sectional view of structure 200 after etching of etched feature 220 is completed. In the present 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. In some embodiments, the flow rate of the passivating agent is gradually reduced at the end of the etching process, so that there is no or almost no metal-containing passivation layer remaining at the end of the etching process.

[0030] In some embodiments, an optional post-etch process (step 120) is provided to remove any remaining metal-containing passivation layer. An exemplary post-etch process for removing the remaining metal-containing passivation layer will use a post-etch process gas containing fluorocarbons and oxygen. In some embodiments, the optional post-etch process further etches or shapes the etched features. An exemplary process for further etching and / or shaping features is to etch the SiO using a post-etch process gas containing fluorocarbons and oxygen. 2 In some embodiments, the features have a CD of no more than 40 nm and a height to width aspect ratio of at least 6:1. Example 2

[0031] In some embodiments, a structure having a dielectric etch layer is provided under a mask (step 104). A carbon-containing (e.g., amorphous carbon) etch layer is provided under a photoresist mask in an etching chamber under a bottom anti-reflective coating (BARC), which in some embodiments is made of a material including silicon and nitrogen or carbon (e.g., silicon nitride, silicon oxynitride, and silicon carbide). In some embodiments, the carbon-containing layer is a carbon-based layer, such as amorphous carbon. In the specification and claims, the carbon-based material will be at least 50% by weight carbon. Figure 3A is a schematic cross-sectional view of a portion of structure 300, where the stack is: BARC layer 307 below photoresist mask 308, below amorphous carbon etch layer 306, below bottom layer 304, below substrate 302. Mask 308 is patterned to form mask features 312. Structure 300 is provided to an etching chamber (step 104).

[0032] To open the BARC 307, an etching gas containing an etchant and a passivator is flowed into the etching chamber (step 108). In the present embodiment, the etchant includes a halogen-containing component and the passivator includes tungsten hexafluoride. In some embodiments, the etching gas also includes an inert diluent. In some embodiments, the inert diluent is one or more rare gases. The pressure range provided by the etching gas is 5mTorr to 500mTorr.

[0033] The etching gas is converted to plasma (step 112). In this embodiment, RF power is provided at one or more frequencies of 400 kHz, 2 MHz, 27 MHz, and 60 MHz. In addition to plasma excitation, RF power can also be used to provide a bias. The amount of bias depends on the application. For higher aspect ratio features, a higher bias is used. In addition, in applications where etch stop is more likely to occur, a higher bias is used to prevent etch stop. Since this embodiment is used to open the BARC, the feature is not a high aspect ratio feature.

[0034] The stack is exposed to a plasma. The plasma selectively etches the etched features in the BARC 307 and deposits a metal-containing passivation on the sidewalls of the etched features (step 116). A metal-containing passivation layer is deposited on the sidewalls of the etched features. In the present embodiment, the metal-containing passivation layer comprises tungsten carbide and / or tungsten nitride, wherein the tungsten is provided by tungsten hexafluoride and the carbon or nitrogen is provided by the BARC 307. To prevent etch stop, sufficient bias power is provided to remove any metal passivation layer on the etch front. In addition, various etching parameters, such as pressure, RF power, bias power, and gas flow rate, can be adjusted to deposit the metal-containing passivation layer on the etched feature sidewalls where bending is most likely to occur, while removing or preventing metal passivation at other locations in the etched features.

[0035] In order to open the amorphous carbon etching layer 306, an etching gas containing an etchant and a passivator is flowed into the etching chamber (step 108). In the present embodiment, the etchant includes an oxygen-containing component, and the passivator includes tungsten hexafluoride. In some embodiments, the etching gas also includes an inert diluent. In some embodiments, the inert diluent is one or more rare gases. In some embodiments, the oxygen-containing component includes at least one of oxygen, ozone, carbon dioxide, carbon monoxide, carbonyl sulfide, nitrogen dioxide, nitrate and sulfur dioxide. The pressure range provided by the etching gas is 5mTorr to 500mTorr.

[0036] The etching gas is converted to plasma (step 112). In the present embodiment, RF power is provided at one or more frequencies of 400kHz, 2MHz, 27MHz and 60MHz. In addition to plasma excitation, RF power can also be used to provide a bias voltage. The amount of bias voltage depends on the application. For higher aspect ratio features, a higher bias voltage is used. In addition, in applications where etch stop is more likely to occur, a higher bias voltage is used to prevent etch stop. Since this embodiment is used to open the mask, the feature is not a high aspect ratio feature.

[0037] The stack is exposed to plasma. The plasma selectively etches the etching features in the etching layer and deposits a metal-containing passivation on the sidewalls of the etching features (step 116). A metal-containing passivation layer is deposited on the sidewalls of the etching features. In the present embodiment, the metal-containing passivation layer comprises tungsten carbide, wherein tungsten is provided by tungsten hexafluoride, and carbon is provided by an amorphous carbon etching layer 306. By providing an etchant and a metal-containing passivation agent simultaneously, rather than providing a passivation agent without providing an etchant at certain times, a metal-containing passivation layer is not formed at the etching front end, thereby avoiding etching stop. In some embodiments, some metal passivation layers may be deposited on the etching front end. In order to prevent etching stop, sufficient bias power is provided to remove any metal passivation layer on the etching front end. In addition, 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 position of the etching feature sidewall that will be most easily bent, while removing or preventing metal passivation at other positions in the etching feature.

[0038] Figure 3B is a schematic cross-sectional view of structure 300 after etch features 320 have 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, an optional post-etching process is provided (step 120). In this embodiment, the bottom layer 304 is a silicon-containing layer located below the amorphous carbon etch layer 306. In this embodiment, the amorphous carbon etch layer 306 is used as a mask to etch the silicon-containing bottom layer 304.

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

[0041] In some embodiments, the post-etch process (step 120) may also include one or more processes to remove the amorphous carbon etch layer 306. Such processes may also remove any remaining metal-containing passivation layer. Figure 3D yes Figure 3C 3. A schematic cross-sectional view of structure 300 after amorphous carbon etch layer 306 is removed is shown in FIG. 3. In some embodiments, the metal-containing passivation layer is removed along with the removal of amorphous carbon etch layer 306. Various implementation plans

[0042] In some embodiments, the stack can be a nitrogen-containing or carbon-containing monolayer, such as a single silicon nitride or amorphous carbon layer. In some embodiments, the stack can be a multilayer, at least one of which is a nitrogen-containing layer or a carbon-containing layer. For example, the stack can be a stack of silicon nitride and silicon oxide alternating layers (ONON). In some embodiments, the requirement that the etching layer contains nitrogen or carbon requires a sufficient amount of nitrogen or carbon to allow the metal-containing passivator to form a metal nitride or metal carbide passivation layer on the feature sidewall. Since the metal nitride or metal carbide passivation layer has a stronger resistance to chemical etching and ion bombardment, the metal nitride or metal carbide passivation layer reduces the bending and CD expansion caused by sidewall etching. Therefore, in some embodiments, etching parameters (such as pressure, RF power, RF bias and temperature) can be adjusted to optimize other etching characteristics, such as selectivity, aspect ratio, dense and isolated load, profile control, CD control and taper. In some embodiments, the bias is adjusted to adjust the aspect ratio. In addition, in some embodiments, the etching parameters are more stable, allowing a larger parameter window.

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

[0044] Some embodiments can not only prevent CD from increasing, but also adjust CD. By controlling the flow rate of the metal-containing gas, CD in the carbon- or nitrogen-containing layer can be adjusted without affecting the mask shape.

[0045] In some embodiments, the etching process can be used to provide capacitor etching. In some embodiments, the etching process can be used to form dynamic random access memory. In some embodiments, if the etching layer is a polysilicon layer, if the passivating agent is tungsten hexafluoride, and if nitrogen and carbon are not present during the etching process, elemental tungsten is deposited on the sidewalls of the polysilicon layer as a passivation layer instead of tungsten carbide or tungsten nitride. In some embodiments, the flow ratio of different components of the etching gas can be changed during the process. Device

[0046] For ease of understanding, Figure 4 Schematic diagram of a plasma processing chamber 400 for plasma processing a substrate in an embodiment. In one or more embodiments, the plasma processing chamber 400 includes: a gas distribution plate 406 providing a gas inlet and an electrostatic chuck (ESC) 416, which are within a plasma processing chamber 404 and are enclosed by a chamber wall 450. Within the plasma processing chamber 404, the substrate 202 is positioned on top of the ESC 416 as a substrate support. The ESC 416 can provide a bias voltage from an ESC power supply 448. A gas source 410 is connected to the plasma processing chamber 404 through 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 the upper electrode. In this embodiment, the upper electrode is the gas distribution plate 406. In a preferred embodiment, 400 kilohertz (kHz), 13.56 megahertz (MHz), 1 MHz, 2 MHz, 60 MHz and / or optionally 27 MHz power sources comprise the RF power source 430 and the ESC power source 448. The controller 435 is controllably connected to the RF power source 430, the ESC power source 448, the exhaust pump 420, and the gas source 410. The high flow liner 460 is a liner within the plasma processing chamber 404 that confines gas from the gas source and has slots 462. The slots 462 maintain a controlled flow of gas to be delivered from the gas source 410 to the exhaust pump 420. An example of such a plasma processing chamber is the Lam Research Corporation of Fremont, California. Etching system. The processing chamber can be a CCP (capacitively coupled plasma) reactor or an ICP (inductively coupled plasma) reactor.

[0047] Figure 55 is a high-level block diagram of a computer system 500 for implementing the controller 435 used in the embodiments of the present invention. The computer system can have a variety of physical forms, ranging from integrated circuits, printed circuit boards, and small handheld devices to huge supercomputers. The computer system 500 may include one or more processors 502, and may also include an electronic display device 504 (for displaying graphics, text, and other data), a main memory 506 (e.g., a random access memory (RAM)), a storage device 508 (e.g., a hard drive), a removable storage device 510 (e.g., an optical drive), a user interface device 512 (e.g., a keyboard, a touch screen, a keypad, a mouse or other pointing device, etc.) and / or a communication interface 514 (e.g., a wireless network interface). The communication interface 514 may allow software and / or data to be transmitted between the computer system 500 and an external device via a link. The system may also include a communication infrastructure 516 (e.g., a communication bus, a crossbar, or a network) that can connect the above-mentioned devices / modules.

[0048] The information transmitted through the communication interface 514 can be in the form of a signal, such as an electronic signal, an electromagnetic signal, an optical signal, or other signal that can be received by the communication interface 514 through a communication link carrying a signal, which can be 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 conceivable that one or more processors 502 can receive information from a network, or can output information to a network during the execution of the above method steps. In addition, the method implementation scheme can be executed alone on a processor, or can be executed in conjunction with a remote processor that shares part of the processing through a network such as the Internet.

[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 memory, disk drive memory, CD-ROMs, and other forms of persistent memory), and should not be interpreted as covering transient subject matter such as carrier waves or signals. Examples of computer code include machine code (e.g., generated by a compiler) and files containing high-level code that are executed by a computer using an interpreter. A computer-readable medium may also be computer code transmitted by a computer data signal embodied in a carrier wave and representing a sequence of instructions that can be executed by a processor.

[0050] Although the present disclosure has been described according to several exemplary embodiments, there are also changes, modifications, permutations and various alternative equivalents that fall within the scope of the present disclosure. It should also be noted that there are many alternative ways to implement the disclosed method and apparatus. Therefore, it is intended that the attached claims be interpreted as including all such changes, modifications, permutations and various alternative equivalents that fall within the true spirit and scope of the present disclosure. As used herein, the phrase "A, B or C" should be interpreted as logic ("A or B or C"), using a non-exclusive logic "or", and should not be interpreted as "only one of A or B or C". Each step in the process can be an optional step and is not required. Different embodiments may remove one or more steps, or steps may be provided in different orders. In addition, each embodiment may provide different steps simultaneously rather than sequentially.

Claims

1. A method for selectively etching at least one feature in a nitrogen or carbon containing dielectric etch layer or a polysilicon etch layer beneath a mask in a stack while providing profile control and CD control, the method comprising: flowing an etching gas including an etchant and a metal-containing passivating agent, forming the etching gas into plasma; as well as The dielectric etch layer or the polysilicon etch layer is exposed to the plasma to simultaneously etch features into the dielectric etch layer and deposit a metal-containing passivation layer on sidewalls of the features. 2 . The method of claim 1 , wherein the etchant comprises at least one of a halogen-containing component and an oxygen-containing component.

3. The method of claim 1, wherein the metal-containing passivating agent comprises a component containing at least one of molybdenum, rhenium, tantalum, tungsten, and vanadium. The method of claim 1 , wherein the mask is a silicon-containing or carbon-containing mask.

5. The method of claim 1, wherein the nitrogen or carbon containing dielectric layer comprises silicon, and wherein the etchant comprises a halogen containing component.

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

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

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

9. The method of claim 1, further comprising chemically removing the metal-containing passivation layer.

10. The method of claim 1, wherein the dielectric etch layer or the polysilicon etch layer is over an underlying layer, further comprising etching the underlying layer. The method of claim 10 , further comprising removing the dielectric etch layer or the polysilicon etch layer.

12. The method of claim 11, wherein the removing of the dielectric etch layer or the polysilicon etch layer removes the metal-containing passivation layer.

13. The method of claim 1, wherein the nitrogen or carbon containing dielectric layer comprises an amorphous carbon or carbon based layer, and wherein the etchant comprises an oxygen containing etchant.

14. The method of claim 13, wherein the oxygen-containing etch comprises at least one of oxygen, ozone, carbon dioxide, carbon monoxide, carbonyl sulfide, nitrogen dioxide, nitrates, and sulfur dioxide.

15. The method of claim 1, wherein the nitrogen- or carbon-containing dielectric etch layer or the polysilicon etch layer is a nitrogen- or carbon-containing dielectric etch layer, and wherein the metal-containing passivation layer comprises a metal carbide or a metal nitride, wherein the carbon of the metal carbide or the nitrogen of the metal nitride is provided by the nitrogen- or carbon-containing dielectric etch layer.

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