Selective deposition of carbon onto photoresist layers in lithography applications

Abstract

The present invention provides a suitable film stack and an etching method for etching features having a desired profile and small dimensions in such a film stack. [Solution] A method for etching a hard mask layer in a structure 300 formed during a patterning process includes: forming a photoresist layer 308 containing an organometallic material on a hard mask layer 306 containing a metal-containing material; exposing the photoresist layer to ultraviolet light through a mask 310 having a selected pattern; removing unirradiated areas of the photoresist layer in order to pattern the photoresist layer; selectively forming a passivation layer 316 containing a carbon-containing material on the upper surface of the patterned photoresist layer 308A; and etching the hard mask layer exposed by the patterned photoresist layer formed on top of the passivation layer.

Description

[Technical Field]

[0001]

[0001] Embodiments of this specification generally relate to film stacks and etching processes for etching such film stacks with high selectivity and good profile control to extreme ultraviolet (EUV) lithography exposure and patterning processes. [Background technology]

[0002]

[0002] Reliably manufacturing submicron-sized features is one of the key requirements for very large-scale integration (VLSI) and ultra-large-scale integration (ULSI) of semiconductor devices. However, with the continuous miniaturization of circuit technology, the size and pitch of circuit features such as interconnects are further increasing the demands on processing power. In multilayer interconnects, which are at the core of this technology, it is necessary to accurately image and position high aspect ratio features such as vias and other interconnects. In order to further increase the density of devices and interconnects, it is important to reliably form these interconnects. Furthermore, it is desirable to reduce waste of intermediate materials such as resists and hard mask materials and to form submicron-sized features and interconnects.

[0003]

[0003] As feature size decreases, the demand for high aspect ratios, defined as the ratio between feature depth and feature width, has steadily increased to 20:1 and above. Developing film stacks and etching processes that can reliably form such high aspect ratio features is a major challenge. However, improper control or low resolution of the lithography exposure and development process can result in inaccurate dimensions of the photoresist layer used to transfer features to the film stack, leading to unacceptable line width roughness (LWR). Large line width roughness (LWR) and undesirable waviness of the photoresist layer caused by the lithography exposure and development process can lead to inaccurate feature transfer to the film stack, ultimately resulting in device failure or reduced yield.

[0004]

[0004] Furthermore, during etching of the film stack, by-products or other materials generated during the etching process may accumulate on the top and / or side walls of the feature being etched, thereby undesirably blocking the openings of the feature formed in the material layer. Different materials selected for the film stack may result in different amounts or profiles of by-products being redeposited on the film stack. Moreover, the openings of the etched feature may be narrowed and / or sealed by the accumulation of redeposited material, preventing the reactive etching solution from reaching the underside of the feature and thus limiting the aspect ratio that can be obtained. Furthermore, the accumulation of redeposited material or by-products may adhere randomly and / or irregularly to the top and / or side walls of the feature being etched, and the resulting irregular profile and growth of redeposited material may alter the flow path of the reactive etching solution, thus resulting in a warped or twisted profile of the feature formed in the material layer. Inaccurate profiles and structural dimensions can cause device structural collapse, ultimately leading to device failure and reduced product yield. Poor etching selectivity for materials contained in the film stack can lead to undesirable and inaccurate profile control, ultimately resulting in device failure.

[0005]

[0005] Therefore, in the art there is a need for a suitable film stack and an etching method for etching features having a desired profile and small dimensions in such a film stack. [Overview of the project]

[0006]

[0006] A method is provided for forming a film stack and etching it to form high aspect ratio features on the film stack. The method described herein facilitates profiling and dimensional control of high aspect ratio features through a suitable sidewall and bottom control scheme using a desired material selected for the film stack. In one or more embodiments, a method for etching a hard mask layer includes forming a photoresist layer containing an organometallic material on a hard mask layer containing a metal-containing material; exposing the photoresist layer to ultraviolet light through a mask having a selected pattern; removing unirradiated areas of the photoresist layer to pattern the photoresist layer; selectively forming a passivation layer containing a carbon-containing material on the upper surface of the patterned photoresist layer; and etching the hard mask layer exposed by the patterned photoresist layer formed on top of the passivation layer.

[0007]

[0007] In another embodiment, a method for etching a film stack includes forming a bottom anti-reflective coating layer on the film stack; forming a hard mask layer containing a metal-containing material on the bottom anti-reflective coating layer; forming a photoresist layer containing an organometallic material on the hard mask layer; exposing the photoresist layer to ultraviolet light through a mask having a selected pattern; removing unirradiated areas of the photoresist layer in order to pattern the photoresist layer; selectively forming a passivation layer containing a carbon-containing material on the upper surface of the patterned photoresist layer; etching the hard mask layer exposed by the patterned photoresist layer on which the passivation layer is formed in order to pattern the hard mask layer; etching the bottom anti-reflective coating layer exposed by the patterned hard mask layer in order to pattern the bottom anti-reflective coating layer; and etching the film stack exposed by the patterned bottom anti-reflective coating layer.

[0008]

[0008] In some embodiments, a method for selectively forming a passivation layer on a patterned photoresist layer includes exposing a photoresist layer containing an organometallic material to ultraviolet light through a mask, removing unirradiated areas of the photoresist layer, and selectively forming a passivation layer containing a carbon-containing material on the upper surface of the photoresist layer.

[0009]

[0009] In order to realize and understand in detail the features of the embodiments of this specification described above, the present disclosure summarized above will be described more specifically with reference to the embodiments illustrated in the accompanying drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of a processing chamber according to one embodiment. [Figure 2] This is a flowchart illustrating a patterning process according to one embodiment. [Figure 3A-F] This is a cross-sectional view of a structure formed during the patterning process shown in Figure 2 according to one embodiment. [Figure 3G-I] This is a cross-sectional view of a structure formed during the patterning process shown in Figure 2 according to one embodiment. [Modes for carrying out the invention]

[0011]

[0013] To facilitate understanding of the embodiments, the same reference numerals are used to indicate identical elements common to the drawings whenever possible. Elements and features of one embodiment are considered to be usefully incorporated into other embodiments without further detail.

[0012]

[0014] However, it should be noted that the attached drawings are merely illustrative examples and should not be considered to limit the scope of the present invention, and that other equally effective embodiments may also be permitted.

[0013]

[0015] A method is provided for forming a film stack and etching it to form high aspect ratio features on the film stack. The method described herein facilitates profile and dimensional control of high aspect ratio features through a suitable sidewall and bottom control scheme with a desired material selected for the film stack. Specifically, the method described herein provides a metal-containing photoresist layer on which a carbon-containing passivation layer is selectively placed, having high etching selectivity from the underlying metal-containing hard mask layer, resulting in high-precision control of the profile of the etched openings in the hard mask layer.

[0014]

[0016] Figure 1 is a cross-sectional view of one embodiment of a processing chamber 100 suitable for performing a patterning process to etch a film stack having a hard mask layer made from a metal-containing material. Suitable processing chambers that can be adapted for use with the teachings disclosed herein include, for example, the ENABLER® or C3® processing chambers available from Applied Materials, Inc., Santa Clara, California. While processing chamber 100 is shown with several features that enable excellent etching performance, other processing chambers can also be adapted to benefit from one or more of the inventive features disclosed herein.

[0015]

[0017] The processing chamber 100 includes a chamber body 102 and a lid 104 that enclose an internal region 106. The chamber body 102 is typically made of aluminum, stainless steel, or other suitable material. The chamber body 102 generally includes side walls 108 and a bottom 110. A substrate support pedestal access port (not shown) is generally defined in the side wall 108 and selectively sealed by a slit valve to facilitate the entry and exit of substrates 103 from the processing chamber 100. An exhaust port 126 is defined in the chamber body 102 and connects the internal region 106 to a pump system 128. The pump system 128 generally includes one or more pumps and throttle valves used to exhaust the internal region 106 of the processing chamber 100 and regulate the pressure. In one or more implementations, the pump system 128 maintains the internal pressure of the internal region 106 at an operating pressure typically between about 10 mTorr and about 500 Torr.

[0016]

[0018] The lid 104 is sealed and supported by the side wall 108 of the chamber body 102. The lid 104 can be opened to allow access to the internal area 106 of the processing chamber 100. The lid 104 includes a window 142 to facilitate optical process monitoring. In one implementation, the window 142 is made of quartz or other suitable material that is transparent to signals used by an optical monitoring system 140 mounted on the outside of the processing chamber 100.

[0017]

[0019] The optical monitoring system 140 is positioned to view at least one of the internal region 106 of the chamber body 102 and / or the substrate 103 positioned on the substrate support pedestal assembly 148 through the window 142. In one or more embodiments, the optical monitoring system 140 is coupled to the lid 104 and uses optical measurements to provide information that enables adjustment of a process, as needed, to compensate for incoming substrate pattern feature mismatches (such as thickness), and to facilitate an integrated deposition process that provides process state monitoring (such as plasma monitoring, temperature monitoring, etc.). One optical monitoring system that can be adapted to benefit from the present invention is the EyeD® full-spectrum, interferometric measurement module available from Applied Materials, Inc. of Santa Clara, California.

[0018]

[0020] The gas panel 158 is coupled to the processing chamber 100 and supplies process gas and / or cleaning gas to the internal region 106. In the embodiment shown in FIG. 1, inlet ports 132', 132'' are provided in the lid 104 such that gas is supplied from the gas panel 158 to the internal region 106 of the processing chamber 100.

[0019]

[0021] The showerhead assembly 130 is coupled to the inner surface 114 of the lid 104. The showerhead assembly 130 includes a plurality of apertures that allow gas to flow from the inlet ports 132', 132'' through the showerhead assembly 130 into the internal region 106 of the processing chamber 100 in a predetermined distribution over the entire surface of the substrate 103 being processed in the processing chamber 100.

[0020]

[0022] The remote plasma source 177 can optionally be coupled to the gas panel 158 such that the mixed gas dissociates more readily from the remote plasma before entering the internal region 106 for processing. The radio frequency (RF) power supply 143 is coupled to the showerhead assembly 130 through a matching network 141. The RF power supply 143 can typically generate up to about 3000 W at an adjustable frequency in the range of about 50 kHz to about 200 MHz.

[0021]

[0023] The showerhead assembly 130 further includes a region that is transmissive to the optical measurement signal. The optically transmissive region or passageway 138 is adapted to allow the optical monitor system 140 to view the substrate 103 positioned in the internal region 106 and / or the substrate support pedestal assembly 148. The passageway 138 may be one aperture or a plurality of apertures formed or disposed in the showerhead assembly 130 that are substantially transmissive to the wavelength of the energy generated by the optical monitor system 140 and reflected back. In one or more embodiments, the passageway 138 includes a window 142 to prevent gas from leaking through the passageway 138. The window 142 may be a sapphire plate, a quartz plate, or other suitable material. The window 142 may alternatively be disposed on the lid 104.

[0022]

[0024] In one implementation, the showerhead assembly 130 is configured to have a plurality of zones that allow separate control of the gases flowing within the internal region 106 of the processing chamber 100. In the embodiment shown in FIG. 1, the showerhead assembly 130 has an inner zone 134 and an outer zone 136 that are separately coupled to the gas panel 158 through separate inlet ports 132', 132''.

[0023]

[0025] The substrate support pedestal assembly 148 is disposed below the showerhead assembly 130 in the internal region 106 of the processing chamber 100. The substrate support pedestal assembly 148 holds the substrate 103 during processing. The substrate support pedestal assembly 148 generally includes a plurality of lift pins (not shown) disposed through the substrate support pedestal assembly 148 configured to lift the substrate 103 from the substrate support pedestal assembly 148 and facilitate the replacement of the substrate 103 using a conventional robot (not shown). An inner liner 118 may closely surround the substrate support pedestal assembly 148.

[0024]

[0026] In one implementation configuration, the substrate support pedestal assembly 148 includes a mounting plate 162, a base 164, and an electrostatic chuck 166. The mounting plate 162 is coupled to the bottom 110 of the chamber body 102 and includes passages for routing utilities, in particular, fluids, power lines, sensor leads, etc., to the base 164 and the electrostatic chuck 166. The electrostatic chuck 166 includes at least one clamp electrode 180 for holding the substrate 103 below the showerhead assembly 130. The electrostatic chuck 166 is driven by a chuck power supply 182 to generate an electrostatic force that holds the substrate 103 to the chuck surface, as is conventionally known. Alternatively, the substrate 103 may be held to the substrate support pedestal assembly 148 by clamping, vacuum, or gravity.

[0025]

[0027] At least one of the base 164 or the electrostatic chuck 166 may include at least one optional embedded heater 176, at least one optional embedded isolator 174, and a plurality of conduits 168, 170 to control the lateral temperature profile of the substrate support pedestal assembly 148. The conduits 168, 170, through which a temperature-regulating fluid circulates, are fluidically coupled to a fluid source 172. The heater 176 is regulated by a power supply 178. The conduits 168, 170 and the heater 176 are used to control the temperature of the base 164, thereby heating and / or cooling the electrostatic chuck 166, and ultimately controlling the temperature profile of the substrate 103 placed on it. The temperatures of the electrostatic chuck 166 and the base 164 may be monitored using a plurality of temperature sensors 190, 192. The electrostatic chuck 166 may further include a plurality of gas passages (not shown), such as grooves, formed on the substrate support pedestal support surface of the electrostatic chuck 166 and fluidly coupled to a heat transfer (or backside) gas supply source such as He. In the process, the backside gas is supplied into the gas passages at a controlled pressure to enhance heat transfer between the electrostatic chuck 166 and the substrate 103.

[0026]

[0028] In one implementation configuration, the substrate support pedestal assembly 148 is configured as a cathode and includes a clamp electrode 180 coupled to a plurality of RF bias power supplies 184, 186. The RF bias power supplies 184, 186 are coupled between the electrode 180 located on the substrate support pedestal assembly 148 and another electrode such as the showerhead assembly 130 or the lid 104 of the chamber body 102. The RF bias power excites and sustains a plasma discharge formed from the gas placed in the processing area of ​​the chamber body 102.

[0027]

[0029] In the embodiment shown in Figure 1, dual RF bias power supplies 184 and 186 are coupled to electrodes 180 located on a substrate support pedestal assembly 148 via a matching circuit 188. The signals generated by the RF bias power supplies 184 and 186 are sent in a single supply to the substrate support pedestal assembly 148 via the matching circuit 188 to ionize the mixed gas supplied to the processing chamber 100, thereby supplying the ionic energy necessary to perform deposition or other plasma processing. The RF bias power supplies 184 and 186 can generally generate RF signals with frequencies from about 50 kHz to about 200 MHz and power from about 0 watts to about 8000 watts, for example, from about 1 watt to about 5000 watts. An additional bias power supply 189 may be coupled to electrodes 180 to control the plasma characteristics.

[0028]

[0030] During the process, the substrate 103 is placed in the substrate support pedestal assembly 148 of the processing chamber 100. Process gas and / or mixed gas are introduced into the chamber body 102 from the gas panel 158 through the showerhead assembly 130. The pump system 128 maintains the pressure inside the chamber body 102 while removing deposited by-products.

[0029]

[0031] A controller 150 is coupled to the processing chamber 100 to control its operation. The controller 150 includes a central processing unit (CPU) 152, memory 154, and support circuits 156 used to control the process sequence and adjust the gas flow from the gas panel 158. The CPU 152 may be any form of general-purpose computer processor that can be used in an industrial environment. Software routines may be stored in memory 154, such as random access memory, read-only memory, floppy disks, or hard disk drives, or other forms of digital storage. The support circuits 156 are conventionally coupled to the CPU 152 and may include a cache, clock circuits, input / output systems, power supplies, etc. Bidirectional communication between the controller 150 and the various components of the processing chamber 100 is handled through a number of signal cables.

[0030]

[0032] Figure 2 is a flowchart of Method 200 for a patterning process according to one embodiment described herein. Figures 3A to 3I are cross-sectional views of a structure 300 formed during the patterning process of Figure 2. Method 200 can be used to form features such as trenches, vias, and openings having desired critical dimensions and profiles. In some embodiments, the dimensions of the features are about 14 nm to about 22 nm, for example, about 18 nm. Structure 300 can be used in gate structures, contact structures, or interconnect structures in front-end or back-end processes. Alternatively, Method 200 can be usefully used to etch other types of structures. Those skilled in the art should recognize that complete processes for forming semiconductor devices and related structures are not shown in the drawings and are not described herein. Various steps are shown in the drawings and described herein, but this does not imply any limitation on the order or presence of such steps. Unless otherwise explicitly specified, steps illustrated or described as a continuous sequence are performed in that manner for illustrative purposes only and do not preclude the possibility that each step may actually be performed simultaneously or overlapping, at least partially, if not entirely.

[0031]

[0033] Method 200 is initiated in step 210 by transferring or providing the film stack 302 to a processing chamber, such as the processing chamber 100 shown in Figure 1, as shown in Figure 3A. In one embodiment, the film stack 302 may have a number of layers stacked perpendicularly to the substrate. The film stack 302 may include one or more metal-containing dielectric layers and one or more silicon-containing dielectric layers. In some embodiments, the metal-containing dielectric layers may be formed from a high dielectric constant material having a dielectric constant greater than 4. Preferred examples of high dielectric constant materials are aluminum oxide (Al2O3), tantalum oxide (Ta2O5), tantalum nitride (TaN), and tantalum oxynitride (TaN). x O y (0≦x, y≦1), Titanium dioxide (TiO2), Titanium nitride (TiN), Zirconium dioxide (ZrO2), Hafnium dioxide (HfO2), Silicon hafnium oxide (HfSiO4), Lanthanum oxide (La2O3), Yttrium oxide (Y2O3), Strontium titanate (SrTiO3), Barium strontium titanate (BST, BaSrTiO3), Bismuth-doped strontium titanate (Bi:SrTiO3), Lead zirconate titanate (PZT, Pb[Zr x Ti 1-x This includes ]O3, 0≦x≦1), etc. Furthermore, the silicon-containing dielectric layer includes silicon oxide (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), silicon oxycarbide (SiON). x C y It can be formed by (0 ≤ x, y ≤ 1), etc.

[0032]

[0034] The substrate may be a semiconductor substrate, silicon wafer, glass substrate, etc. The substrate may be crystalline silicon (for example, Si <100> or Si <111> The substrate may be formed from materials such as silicon oxide, strained silicon, silicon germanium, germanium, doped or undoped polysilicon, doped or undoped silicon wafers and patterned or unpatterned wafer silicon-on-insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, or sapphire. The substrate may have various dimensions, such as 200 mm, 300 mm, 450 mm, or other diameters, and may be rectangular or square panels.

[0033]

[0035] In step 220, a bottom anti-reflective coating (BARC) layer 304 is formed on the film stack 302, as shown in Figure 3A. In some embodiments, the BARC layer 304 is made of a carbon-containing material such as boron-doped amorphous carbon. The BARC layer 304 may be a Saphira® Advanced Patterning Film (APF) carbon hard mask manufactured by Applied Materials, Inc., located in Santa Clara, California. In some embodiments, the BARC layer 304 is a high-density carbon-containing layer with superior film properties such as improved hardness and density. Due to such hardness and density, the BARC layer 304 acts as a stronger barrier against metal penetration than conventional spin-on carbon (SOC) hard masks, significantly preventing and reducing nano-faults.

[0034]

[0036] The BARC layer 304 can be formed by a physical vapor deposition (PVD) process, a plasma chemical vapor deposition (PECVD) process, or other suitable deposition process. In one embodiment, the BARC layer 304 is composed of C2H2, C3H6, CH4, C4H8, 1,3-dimethyladamantane, bicyclo[2.2.1]hepta-2,5-diene (2,5-norbornadiene), adamantane (C 10 H 16 ), Norbornen (C7H10 ) A diamond-like carbon layer formed by a chemical vapor deposition (CVD) (plasma and / or thermal) process using a hydrocarbon-containing mixed gas including a precursor such as or a combination thereof. The deposition process can be carried out at a temperature in the range of -50°C to 600°C. The deposition process can be carried out at a pressure in the range of 0.1 mTorr to 10 Torr in the internal region 106 of the processing chamber 100. The hydrocarbon-containing mixed gas may further include a carrier gas such as He, Ar, Xe, N2, H2, or a combination thereof, and an etching gas such as Cl2, CF4, NF3, or a combination thereof for improving film quality. Plasma (for example, capacitively coupled plasma) can be formed from either the upper and bottom electrodes or the side electrodes of the processing chamber 100. The electrodes can be formed from, without limitation, a single power supply electrode, a dual power supply electrode, or a further electrode at which a plurality of frequencies such as 350 KHz, 2 MHz, 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, and 100 MHz are alternately or simultaneously used in the CVD system.

[0035]

[0037] In step 230, a hard mask layer 306 is formed on the BARC layer 304, as shown in Figure 3B. The hard mask layer 306 may be a metal oxide layer. The material selected for the hard mask layer 306 may affect the reflection and / or absorption efficiency of extreme ultraviolet (EUV) radiation having wavelengths of about 5 nm to about 20 nm, for example, about 13.5 nm, during the lithography exposure process. Therefore, by appropriately selecting the material for the hard mask layer 306, the performance of the EUV lithography exposure process can be improved, such as high lithography resolution, defect reduction, photoresist layer profile control, energy dose reduction, and / or line edge roughness reduction. For example, since materials with higher metal concentrations may provide a higher absorption coefficient for EUV radiation, the hard mask layer 306 may be formed from a metal-containing material such as a metal dielectric layer containing one or more metal elements with atomic numbers greater than 28, such as 29 to 32, 37 to 51, and 55 to 83. Suitable metallic elements include tin (Sn), tantalum (Ta), indium (In), gallium (Ga), zinc (Zn), zirconium (Zr), aluminum (Al), or combinations thereof. Furthermore, lower concentrations of silicon dopant and / or oxygen elements in the metal-containing material can further increase free carriers, enhance the absorption coefficient of EUV radiation, and reduce the likelihood of defect formation. Suitable examples of metal-containing materials for the hard mask layer 306 may include or include tin oxide (SnO), silicon tin oxide (SnSiO), tantalum oxide (TaO), indium tin oxide (InSnO), indium gallium zinc oxide (IGZO), one or more alloys thereof, one or more dopants thereof, or any combination thereof having a ratio of metallic element to silicon or oxygen element (metal:Si / O) from about 80:1 / 19 to about 90:1 / 9. The metal-containing material for the hard mask layer 306 is subjected to 1 × 10⁻¹⁶ radiation under EUV radiation with wavelengths ranging from approximately 5 nm to approximately 20 nm. 5 (cm 2 It may have an EUV absorption cross-section exceeding ( / mol). In one or more embodiments, the hard mask layer 306 has a thickness of about 10 Å to about 500 Å, for example, about 20 Å to about 200 Å, for example, about 50 Å to about 100 Å.

[0036]

[0038] In some embodiments, the hard mask layer 306 comprises multiple layers. The hard mask layer 306 may have multiple layers formed from different metal-containing materials. The selection of metal-containing materials for the multiple layers is based on the different absorption coefficients of the metal-containing materials. For example, multiple layers having high to low, low to high, or alternating high and low absorption coefficients may be formed sequentially to enhance the reflection of EUV radiation during the lithography exposure process. In one or more embodiments, a metal element selected for one of the multiple layers may have an atomic number greater than 28, such as greater than 35, while another metal element may have an atomic number less than 28.

[0037]

[0039] In some embodiments, the hard mask layer 306 comprises a two-layer structure, having a first portion (e.g., upper or lower layer) containing metallic elements with atomic numbers greater than 28, such as 29 to 32, 37 to 51, and 55 to 83, and a second portion (e.g., lower or lower layer) containing elements with atomic numbers less than 28, such as 3 to 8, 11 to 16, and 19 to 27.

[0038]

[0040] In some embodiments, the hard mask is formed as a gradient having different ratios of silicon and / or oxygen to metal elements in the hard mask layer 306, so that different absorption coefficients are obtained along the bulk film of the hard mask layer 306. For example, the concentration of metal elements in the hard mask layer 306 can be gradually increased or decreased with increasing thickness of the hard mask layer 306. Alternatively, each layer of the two-layer structure, or multiple layers of the hard mask layer 306, may also be gradient layers. For example, in a two-layer structure of the hard mask layer 306, the upper part of the hard mask layer 306 may have a relatively high concentration of metal elements or a pure metal layer (e.g., a metallic Sn layer) with low resistivity, while the lower part of the hard mask layer 306 may have a high concentration of silicon and / or oxygen.

[0039]

[0041] The hard mask layer 306 can be formed by a CVD process, a PVD process, an atomic layer deposition (ALD) process, a spin-on coating process, a spray coating process, or other suitable deposition process. In some embodiments, a carrier gas and / or inert gas with a relatively high atomic weight, such as Xe or Kr, may be used during the plasma CVD or PVD process for forming the hard mask layer 306. The temperature controlled during the formation of the hard mask layer 306 can be controlled from -50°C to about 250°C. It is thought that controlling the temperature to a relatively low temperature, for example below 250°C, during the formation of the hard mask layer 306 allows for the formation of the hard mask layer 306 at a relatively slow deposition rate, making it easier to obtain a film surface with a relatively smooth surface.

[0040]

[0042] In step 240, as shown in Figure 3C, a photoresist layer 308 is formed on the hard mask layer 306. In the embodiments described herein, the photoresist layer 308 is formed of an organometallic material containing an organic ligand. The organometallic material layer is formed of a metal with an oxo ligand (O 2- ) and hydroxo ligand (OH - ), as well as polymeric metal oxo / hydroxo networks bonded to organic ligands, or polynuclear metal oxo / hydroxo species having organic ligands, can be formed from these.

[0041]

[0043] The photoresist layer 308 can be formed by a CVD process, PVD process, ALD process, spin-on coating process, spray coating process, or other suitable deposition process using a precursor solution containing a metal oxohydroxocation having an organic ligand in an organic solvent. Here, a metal (M) oxohydroxocation is a metal (M) oxohydroxocation that, in aqueous solution, is bonded to an oxygen atom (O) and forms a hydrogen ion (H). - ) releases oxo ligand (O 2- ) and / or hydroxo ligand (OH -A metal (M) oxo-hydroxocation is one or more metal (M) ions that form a oxo-hydroxocation. A metal (M) oxo-hydroxocation can further bond to an organic ligand to form one or more metal-carbon (MC) ligand bonds and / or metal carboxylate (M-O2C) ligand bonds. Suitable metals (M) for the formation of metal oxo / hydroxocations include metals from groups 13, 14, and 15, such as tin (Sn), antimony (Sb), and indium (In). To produce more complex multinuclear metal oxo / hydroxocations (i.e., containing two or more metal atoms), additional metals, such as Ti, Zr, Hf, V, Co, Mo, W, Al, Ga, Si, Ge, P, As, Y, La, Ce, Lu, or combinations thereof, can be blended into the precursor solution. The additional metals may be substitutes for or added to tin (Sn), antimony (Sb), and / or indium (In). When metal ion blends are used, the molar ratio of non-tin / antimony / indium ions per tin / antimony / indium metal ions is up to about 1 in one embodiment and from about 0.1 to about 0.75 in other embodiments. In some embodiments, tin (Sn) or indium (In) is used in the precursor solution to form a photoresist layer having strong absorption of extreme ultraviolet (EUV) radiation at a wavelength of 13.5 nm and good absorption of ultraviolet (UV) radiation at a wavelength of 193 nm in combination with organic ligands. In some embodiments, Hf is used as an electron beam material and to obtain good absorption of extreme ultraviolet (EUV) radiation. In some embodiments, one or more metal compositions including Ti, V, Mo, W, or combinations thereof are added to shift the absorption edge to longer wavelengths and obtain sensitivity to ultraviolet (UV) radiation at a wavelength of 248 nm.

[0042]

[0044] The organic ligands may be, for example, alkyl (e.g., methyl, ethyl, propyl, butyl, t-butyl, aryl (phenyl, benzyl)), alkenyl (e.g., vinyl, allyl), and carboxylates (e.g., acetate, propanoic acid, butanoic acid, benzoic acid). The ratio of the concentration of the organic ligand to the concentration of the metal oxo-hydroxocation in the precursor solution is about 0.25 to about 4 in one example, about 0.5 to about 3.5 in another example, about 0.75 to about 3 in yet another example, and about 1 to about 2.75 in yet another example. Those skilled in the art will recognize that additional ranges of organic ligand concentrations within the above express ranges are also conceivable and within the scope of this disclosure.

[0043]

[0045] The organic solvent may be an alcohol, an ester, or a combination thereof. In some embodiments, the organic solvent includes aromatic compounds (e.g., xylene, toluene), esters (propylene glycol monomethyl ether acetate, ethyl acetate, ethyl lactate), alcohols (e.g., 4-methyl-2-pentanol, 1-butanol, anisole), ketones (e.g., methyl ethyl ketone), etc.

[0044]

[0046] In some embodiments, the deposited photoresist layer 308 has a thickness of about 1 nm to about 1 μm, for example, about 8 nm to about 13 nm.

[0045]

[0047] In step 250, the photoresist layer 308 is exposed to radiation according to a selected pattern that includes features such as trenches, vias, and openings having desired critical dimensions and profiles to be formed on the film stack 302, as shown in Figure 3D. The selected pattern is transferred to a corresponding pattern or latent image of the photoresist layer 308 having irradiated and unirradiated areas. Upon exposure to radiation, the photoresist layer 308 absorbs radiation that provides enough energy to cleave bonds between metal and organic ligands (i.e., metal-carbon (MC) ligand bonds and / or metal-carboxylic acid (M-O2C) ligand bonds) within the irradiated area of ​​the photoresist layer 308. This cleavage may result in a compositional change in the irradiated area of ​​the photoresist layer 308, either through the formation of metal hydroxide (M-OH) ligand bonds or through condensation to form metal-oxygen (MOM) ligand bonds.

[0046]

[0048] Due to the absorption of a sufficient amount of radiation, a contrast in material properties exists between the irradiated area of ​​the photoresist layer 308 that does not have or substantially does not have organic ligands and the unirradiated area of ​​the photoresist layer 308 that still has organic ligands. For example, the unirradiated area of ​​the photoresist layer 308 with organic ligands is relatively hydrophobic, while the irradiated area of ​​the photoresist layer 308 without organic ligands is less hydrophobic (i.e., more hydrophilic) than the unirradiated area of ​​the photoresist layer 308. By utilizing this contrast, the photoresist layer 308 can provide positive tone patterning (the irradiated area becomes soluble in the developer) and negative tone patterning (the irradiated area becomes insoluble in the developer) with the appropriate developer.

[0047]

[0049] The radiation may be electromagnetic radiation, an electron beam, or other suitable radiation. The radiation can be directed through the mask 310 to the photoresist layer 308, or the radiation beam can be controllably scanned across the entire photoresist layer 308. Depending on the desired spatial resolution for patterning the underlying film stack 302, the electromagnetic radiation may have a desired wavelength or wavelength range, such as visible radiation, ultraviolet (UV) radiation (100 nm to 400 nm, including extreme ultraviolet (EUV) from 10 nm to 121 nm and far ultraviolet (FUV) from 122 nm to 200 nm), or X-rays (soft X-rays from 0.1 nm to 10 nm). Higher resolution patterns can be achieved using shorter wavelength radiation such as ultraviolet radiation, X-rays, or electron beams. For example, EUV radiation generated from a Xe or Sn plasma source excited with a high-energy laser or discharge pulse can be used for 13.5 nm lithography.

[0048]

[0050] In some embodiments, the contrast can be enhanced by post-irradiation heat treatment.

[0049]

[0051] In step 260, as shown in Figure 3E, the photoresist layer 308 is developed to pattern the photoresist layer 308 according to the selected pattern. The patterned photoresist layer 308A defines openings 312 that expose the surface 314 of the underlying hard mask layer 306 for etching.

[0050]

[0052] The developer for developing the irradiated photoresist layer 308 and removing the unirradiated areas of the photoresist layer 308 (i.e., negative-tone patterning) to form the patterned photoresist layer 308A may contain organic solvents such as the solvent used in the precursor solution. In some embodiments, suitable developers include aromatic compounds (e.g., benzene, xylene, toluene), esters (e.g., propylene glycol monomethyl acetate, ethyl acetate, ethyl lactate, n-butyl acetate, butyrolactone), alcohols (e.g., 4-methyl-2-pentanol, 1-butanol, isopropanol, anisole), ketones (e.g., methyl ethyl ketone, acetone, cyclohexanone), ethers (e.g., tetrahydrofuran, dioxane), etc. Development is carried out for about 5 seconds to about 30 minutes in one embodiment, about 8 seconds to about 15 minutes and about 10 seconds to about 10 minutes in other embodiments.

[0051]

[0053] In some embodiments, the developer may include additional compositions to facilitate the development process, for example, to improve contrast, sensitivity, and line width roughness, and to suppress the formation and precipitation of metal oxide particles. Suitable additives include, for example, molten salts having cations selected from the group consisting of ammonium, d-block metal cations (hafnium, zirconium, lanthanum, etc.), f-block metal cations (cerium, lutetium, etc.), p-block metal cations (aluminum, tin, etc.), alkali metals (lithium, sodium, potassium, etc.), and combinations thereof, as well as molten salts having anions selected from the group consisting of fluorides, chlorides, bromides, iodides, nitrates, sulfates, phosphates, silicates, borates, peroxides, butoxides, formates, ethylenediaminetetraacetic acid (EDTA), tungstic acid, molybdic acid, and combinations thereof. Other potentially useful additives include molecular chelating agents such as polyamines, alcoholamines, amino acids, or combinations thereof. If optional additives are present, the developer may contain about 10% by weight or less of the additive in one embodiment, and about 5% by weight or less of the additive in another embodiment. Those skilled in the art will recognize that additional ranges of additive concentrations within the above express range are also conceivable and fall within the scope of this disclosure.

[0052]

[0054] The developer can be applied to a photoresist layer 308 that has been irradiated using a spin-on coating process, a spray coating process, or other suitable coating process. In some embodiments, spin washing and / or drying may be performed to complete the development process. Suitable washing solutions include ultrapure water, methyl alcohol, ethyl alcohol, propyl alcohol, and combinations thereof.

[0053]

[0055] In some embodiments, the patterned photoresist layer 308A may be treated to further condense and dehydrate the material. In some embodiments, the patterned photoresist layer 308A may be heated to temperatures of about 100°C to about 600°C in one embodiment, about 175°C to about 500°C in another embodiment, and about 200°C to about 400°C in yet another embodiment. Heating may be carried out for at least about 1 minute in one embodiment, about 2 minutes to about 1 hour in another embodiment, and about 2.5 minutes to about 25 minutes in yet another embodiment. Heating may be carried out in an atmosphere of air, vacuum, or an inert gas such as Ar or N2. Those skilled in the art will recognize that additional ranges of temperature and time for heat treatment within the express ranges above are also conceivable and within the scope of this disclosure.

[0054]

[0056] In some embodiments, adjacent linear segments of adjacent structures may have an average pitch of about 60 nm or less, about 50 nm or less in some embodiments, and about 40 nm or less in further embodiments.

[0055]

[0057] In step 270, as shown in Figure 3F, a passivation layer 316 is selectively formed on the patterned photoresist layer 308A before etching the hard mask layer 306. The passivation layer 316 can be formed by supplying a mixed deposition gas to the patterned photoresist layer in a PVD chamber, or by in-situ from a carbon-containing material in an etching chamber. In the embodiments described herein, the passivation layer 316 is primarily formed on the upper surface 318 of the patterned photoresist layer 308A, rather than on the sidewalls 320 of the patterned photoresist layer 308A or the exposed surface 314 of the hard mask layer 306. Thus, the profile (e.g., dimensions and shape dimensions) of the opening 312 defined by the patterned photoresist layer 308A is maintained unchanged to facilitate the transfer of the opening 312 to the hard mask layer 306 without change in the profile.

[0056]

[0058] Without being constrained by theory, it is considered that carbon atoms are bonded to the upper surface 318 (i.e., the irradiation area) of the photoresist layer 308 having metal hydroxide (M-OH) ligand bonds and metal oxygen (MOM) ligand bonds by cleaving the bonds between the metal and the organic ligands (i.e., metal-carbon (MC) ligand bonds and / or metal carboxylate (M-O2C) ligand bonds). The side walls 320 of the patterned photoresist layer 308A do not contain metal hydroxide (M-OH) ligand bonds and metal oxygen (MOM) ligand bonds to which carbon atoms can be bonded, in order to maintain the composition of the unirradiated photoresist layer 308 which retains the organic ligands as they are. Also, the exposed surface 314 of the hard mask layer 306 does not contain metal hydroxide (M-OH) ligand bonds and metal oxygen (MOM) ligand bonds, so carbon atoms are not bonded to the exposed surface 314 of the hard mask layer 306.

[0057]

[0059] In one or more embodiments, the mixed deposition gas includes a carbon-containing gas such as CO gas or CH4 gas. As described above, the hard mask layer 306 is formed from a material containing a metallic element such as tin (Sn), and the photoresist layer 308 is also formed from a material containing a metallic element such as tin (Sn), resulting in poor etching selectivity between the hard mask layer 306 and the photoresist layer 308. Therefore, when the hard mask layer 306 on which the photoresist layer 308 is placed is etched, the control of the etched opening profile in the hard mask layer 306 becomes inaccurate, which can ultimately lead to device failure. The presence of the passivation layer 316 on top of it increases the etching selectivity of the patterned photoresist layer 308B from the hard mask layer 306, resulting in more precise control of the etched opening profile in the hard mask layer 306.

[0058]

[0060] In step 280, the hard mask layer 306 is etched to transfer the openings 312 of the patterned photoresist layer 308A to the hard mask layer 306, as shown in Figure 3G. The patterned hard mask layer 306A defines openings 322 that expose the surface 324 of the underlying BARC layer 304 for etching. In one or more embodiments, the etching process in step 280 is carried out by supplying an etching mixed gas into the processing chamber 100 while maintaining the temperature of the substrate support pedestal assembly 148 from room temperature (e.g., about 23°C) to a maximum of about 150°C.

[0059]

[0061] In some embodiments, the etching mixture gas includes at least one halogen-containing gas. The halogen-containing gas may include a fluorine-containing gas, a chlorine-containing gas, or a bromide-containing gas. Preferred examples of halogen-containing gases include SF6, SiCl4, Si2Cl6, NF3, HBr, Br2, CHF3, CH2F2, CF4, C2F, C4F6, C3F8, HCl, C4F8, Cl2, HF, CCl4, CHCl3, CH2Cl2, and CH3Cl. In some embodiments, a silicon-containing gas may also be supplied to the etching mixture gas. Preferred examples of silicon-containing gases include SiCl4, Si2Cl6, SiH4, Si2H6, etc. More specifically, examples of chlorine-containing gases include HCl, Cl2, CCl4, CHCl3, CH2Cl2, CH3Cl, SiCl4, Si2Cl6, etc., and examples of bromide-containing gases include HBr, Br2, etc. Additionally, if necessary, reactive gases containing oxygen or nitrogen, such as O2, N2, N2O, NO2, O3, and H2O, may be supplied to the etching mixture gas.

[0060]

[0062] In one or more embodiments, the halogen-containing gas used to etch the hard mask layer 306 includes a chlorine-containing gas or a bromide-containing gas. While the etching mixture gas is supplied into the processing chamber, an inert gas may be optionally supplied to the etching mixture gas to assist in profile control as needed. Examples of inert gases supplied to the mixture gas include Ar, He, Ne, Kr, Xe, etc. In one specific example, the etching mixture gas used to etch the hard mask layer 306 of a metal-containing material (e.g., a Sn / SnO / SnSiO layer) includes HBr, Cl2, Ar, He, or a combination thereof.

[0061]

[0063] During etching, the chamber pressure of the etching gas mixture is also adjusted. In one or more embodiments, the process pressure of the plasma processing chamber is adjusted from about 2 mTorr to about 100 mTorr, for example, from about 3 mTorr to 20 Torr, for example, from about 6 mTorr. An RF source or bias power may be applied in the presence of the etching gas mixture to maintain the plasma formed from continuous or pulsed mode as needed. For example, to maintain the plasma in the etching chamber, an RF power supply having a frequency of about 13.56 MHz may be applied to an inductively coupled antenna source at an energy level of about 200 watts to about 1000 watts, for example, about 500 watts. Furthermore, an RF bias power having a frequency of about 2 MHz to about 13.56 MHz may be applied at less than 500 watts, for example, from about 0 watts to about 450 watts, for example, about 150 watts.

[0062]

[0064] In one or more embodiments, the RF bias power and RF power supply may be pulsed in the processing chamber 100 during etching in step 280. The RF bias power and RF power supply may be pulsed synchronously or asynchronously within the processing chamber. In some embodiments, the RF bias power and RF power supply are pulsed asynchronously within the processing chamber. For example, the RF power supply may be pulsed into the processing chamber before the RF bias power is pulsed. For example, the RF bias power may be in a pulsed mode synchronous with the RF power supply, or there may be a time delay with respect to the RF power supply. In one or more embodiments, the RF power supply and RF bias power are pulsed at about 5% to about 75% of each duty cycle. Each duty cycle, for example, between each time unit, is about 0.1 milliseconds (ms) to about 10 ms.

[0063]

[0065] In an example of the etching mixed gas supplied in step 280, O2 gas may be supplied into the chamber at a rate of approximately 0 sccm to approximately 50 sccm. Halogen-containing gases such as HBr may be supplied at a flow rate of approximately 25 sccm to approximately 250 sccm, for example, approximately 100 sccm.

[0064]

[0066] In step 290, the BARC layer 304 is etched so that the openings 322 in the patterned hard mask 360A are transferred to the BARC layer 304, as shown in Figure 3H. The patterned BARC layer 304A defines openings 326 that expose the surface 328 of the underlying film stack 302. The etching gas mixture used to etch the BARC layer 304 in step 290 may be the same as the etching gas mixture used to etch the hard mask layer 306 in step 280. Alternatively, the etching gas mixture used to etch the BARC layer 304 in step 290 may be different from the etching gas mixture used to etch the hard mask layer 306 in step 280. In one or more embodiments, the etching gas mixture used to etch the BARC layer 304 in step 290 may include a chlorine-containing gas such as HCl or Cl2 gas.

[0065]

[0067] After the opening 326 is formed in the BARC layer 304, a scum removal or stripping process may be performed to remove any remaining passivation layer 316, if any, as shown in Figure 3I. Note that further etching or patterning processes may be performed to continue transferring the opening 326 to the film stack 302 and to form a selected pattern within the film stack 302 that includes features such as trenches, vias, and openings having the desired critical dimensions and profiles.

[0066]

[0068] Embodiments described herein provide a method for forming a metal-containing photoresist layer on which a carbon-containing passivation layer is selectively placed, having high etching selectivity from the underlying metal-containing hard mask layer, thereby resulting in high-precision control of the profile of apertures etched into the hard mask layer. This improves lithography exposure accuracy, including high resolution, low energy dose, good photoresist profile control, and low line edge roughness.

[0067]

[0069] While the foregoing applies to embodiments of this disclosure, it is possible to devise other further embodiments of this disclosure without departing from its fundamental scope as defined by the following claims. All documents described herein, including all prior documents and / or test procedures, are incorporated herein by reference to the extent that they do not contradict the text. As is evident from the above general description and specific embodiments, the forms of this disclosure have been illustrated and described, but various modifications can be made without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited thereto. Similarly, the term “comprising” is considered synonymous with the term “containing” for the purposes of U.S. law. Similarly, whenever a configuration, element, or group of elements is preceded by the transitional phrase “comprising,” it is also possible to conceive of the same configuration or group of elements preceded by the transitional phrase “essentially consisting of,” “consisting of,” “selected from a group consisting of,” or “is,” and vice versa.

[0068]

[0070] Specific embodiments and features have been described using a set of upper and lower limits. Naturally, unless otherwise specified, ranges can include any combination of two values, for example, any combination of a lower and upper limit, any combination of two lower limits, and / or any combination of two upper limits. Specific lower limits, upper limits, and ranges are described in one or more of the following claims.

Claims

1. A method for etching a hard mask layer, Forming a photoresist layer containing an organometallic material on a hard mask layer containing a metal-containing material, Exposing the photoresist layer to ultraviolet light through a mask having a selected pattern, In order to pattern the photoresist layer, the non-irradiated areas of the photoresist layer are removed, A passivation layer containing a carbon-containing material is selectively formed on the upper surface of the patterned photoresist layer. Etching the hard mask layer exposed by the patterned photoresist layer formed on top of the passivation layer. A method that includes this.

2. The method according to claim 1, wherein the organometallic material comprises one or more metal elements and an organic ligand.

3. The method according to claim 2, wherein the one or more metal elements include tin (Sn).

4. The method according to claim 2, wherein the organic ligand is selected from the group consisting of alkyl, alkenyl, and carboxylate salts.

5. Forming the aforementioned passivation layer is CO and CH are placed on the patterned photoresist layer. ４ To supply a deposit gas containing a gas selected from the group consisting of the following: The method according to claim 1, including the method described in claim 1.

6. A method for etching a film stack, Forming a bottom anti-reflective coating layer on the film stack, A hard mask layer containing a metal-containing material is formed on the bottom anti-reflective coating layer. A photoresist layer containing an organometallic material is formed on the hard mask layer. Exposing the photoresist layer to ultraviolet light through a mask having a selected pattern, In order to pattern the photoresist layer, the non-irradiated areas of the photoresist layer are removed, A passivation layer containing a carbon-containing material is selectively formed on the upper surface of the patterned photoresist layer. In order to pattern the hard mask layer, the hard mask layer exposed by the patterned photoresist layer on which the passivation layer is formed is etched, In order to pattern the bottom anti-reflective coating layer, the bottom anti-reflective coating layer exposed by the patterned hard mask layer is etched, Etching the film stack exposed by the patterned bottom anti-reflective coating layer and A method that includes this.

7. The method according to claim 6, wherein the organometallic material comprises one or more metal elements and an organic ligand.

8. The method according to claim 7, wherein the one or more metal elements include tin (Sn).

9. The method according to claim 7, wherein the organic ligand is selected from the group consisting of alkyl, alkenyl, and carboxylate salts.

10. Forming the aforementioned passivation layer is CO and CH are placed on the patterned photoresist layer. ４ To supply a deposit gas containing a gas selected from the group consisting of the following: The method according to claim 6, including the method described in claim 6.

11. The method according to claim 6, wherein the metal-containing material of the hard mask layer contains tin (Sn).

12. The method according to claim 11, wherein the metal-containing material of the hard mask layer is selected from the group consisting of tin oxide (SnO), silicon tin oxide (SnSiO), tantalum oxide (TaO), indium tin oxide (InSnO), indium gallium zinc oxide (IGZO), and any combination thereof.

13. The method according to claim 6, wherein the bottom anti-reflective coating layer includes a carbon-containing material.

14. A method for selectively forming a passivation layer on a patterned photoresist layer, Exposing a photoresist layer containing organometallic material to ultraviolet light through a mask, To remove the unirradiated area of ​​the photoresist layer, A passivation layer containing a carbon-containing material is selectively formed on the upper surface of the photoresist layer. A method that includes this.

15. The method according to claim 14, wherein the organometallic material comprises one or more metal elements and an organic ligand.

16. The method according to claim 15, wherein the one or more metal elements include tin (Sn).

17. The method according to claim 15, wherein the one or more metallic elements are selected from the group consisting of tin (Sn), antimony (Sb), indium (In), and any combination thereof.

18. The method according to claim 15, wherein the organic ligand is selected from the group consisting of alkyl, alkenyl, and carboxylate salts.

19. Heating the patterned photoresist layer The method according to claim 14, further comprising:

20. Forming the aforementioned passivation layer is CO and CH are placed on the patterned photoresist layer. ４ To supply a deposit gas containing a gas selected from the group consisting of the following: The method according to claim 14, including the method described in claim 14.

Images