Method for reducing defects after stepwise infiltration synthesis

Abstract

Embodiments disclosed herein describe methods for processing a substrate. In one embodiment, a method for processing layers of a film stack includes pre-treating the surface of the lower layer of the film stack formed on a substrate and forming a metal oxide within the photoresist layer of the film stack by heating a methyl-containing material in a processing environment near the film stack. The film stack includes a photoresist layer placed on top of the lower layer in contact with the lower layer, and a lower layer placed on the substrate. Subsequently, the metal oxide-implanted photoresist is etched.

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to methods for enhancing photoresist profile control. In particular, embodiments of the present disclosure provide a method for forming metal oxides in a photoresist to improve profile control while reducing defects in the post-process of sequential infiltration synthesis (SIS).

Background Art

[0002]

[0001] Integrated circuits have evolved into complex devices that can include millions of components (e.g., transistors, capacitors, and resistors) on a single chip. Photolithography can be used to form components on a chip. Generally, the process of photolithography includes forming a photoresist layer on a substrate. This photoresist layer can be formed, for example, by spin coating. The photoresist layer can include a resist resin and a photoacid generator. The photoacid generator changes the solubility of the photoresist in the development process when exposed to electromagnetic radiation in a subsequent exposure step. The electromagnetic radiation can have any suitable wavelength, such as a wavelength in the extreme ultraviolet region, and can be from any suitable source, such as an ArF laser at 193 nm, an electron beam, an ion beam, or other sources. Next, in the pre-exposure bake process, excess solvent can be removed.

[0003]

[0002] In the exposure step, a photomask or reticle can be used to selectively expose specific regions of the photoresist layer disposed on the substrate to electromagnetic radiation. Other exposure methods can be maskless exposure methods. Exposure to light can decompose the photoacid generator, generate an acid, and result in a potential acid image in the resist resin. After exposure, the substrate can be heated in a post-exposure bake process. During the post-exposure bake process, the acid generated by the photoacid generator reacts with the resist resin in the photoresist layer, changing the solubility of the resist in the photoresist layer during a subsequent development process.

[0004]

[0003] After exposure and firing, the substrate and photoresist layer are developed and rinsed. Subsequently, a patterned photoresist layer is formed on the substrate. After the development and rinsing processes, openings are defined within the patterned photoresist layer, exposing the underlying target material for etching and transferring features onto the target material. Factors such as improper control or low resolution of the lithography exposure process, or the elasticity of the pattern layer, can cause deterioration of the critical dimensions of the patterned photoresist layer, resulting in unacceptable line width roughness (LWR). High line width roughness (LWR) of the patterned photoresist layer can lead to inaccurate feature transfer to the target material, ultimately resulting in premature device failure and yield loss.

[0005]

[0004] One approach to improving pattern transfer involves performing a post-processing stepwise infiltration synthesis to infiltrate the photoresist with a metal oxide material. Incorporating metal oxides into the photoresist improves etching resistance and improves pattern transfer to the underlying layer. However, the metal oxides may infiltrate the underlying trench regions, potentially causing undesirable bridging defects during the subsequent pattern transfer process.

[0006]

[0005] Therefore, an improved process is needed for patterning the photoresist layer. [Overview of the project]

[0007]

[0006] In one embodiment, a method for processing the layers of a film stack includes pre-treating the surface of the lower layer of the film stack formed on a substrate and forming a metal oxide in the photoresist layer of the film stack by heating a methyl-containing material in a processing environment near the film stack. The film stack includes a photoresist layer placed on top of the lower layer in contact with the lower layer and a lower layer placed on a substrate. Subsequently, the metal oxide-implanted photoresist is etched.

[0008]

[0007] In another embodiment, a method for processing layers of a film stack is provided. This method involves forming a metal oxide within the photoresist layer of a film stack by heating a methyl-containing material in a processing environment adjacent to a film stack, which includes a photoresist layer disposed on top of the film stack in contact with a lower layer and a lower layer disposed on a substrate. To remove the metal oxide from the lower layer, a pretreatment process is performed on the surface of the lower layer to etch the film stack and the photoresist layer containing the metal oxide.

[0009]

[0008] In yet another embodiment, a substrate processing method (if provided). This method involves placing a substrate including a lower layer and a photoresist layer in a processing chamber, performing a pre-processing process on the surface of the lower layer to form a SAM material on the surface of the lower layer, exposing the photoresist material to a methyl-containing material, exposing the processing chamber to a methyl-containing material, oxidizing the methyl-containing material to form a processed photoresist, and etching the surface of the lower layer with a metal oxide material.

[0010]

[0009] To enable a detailed understanding of the above-described features of the embodiments of the present disclosure, a more specific description of the present disclosure, which has been briefly summarized above, can be obtained by referring to the embodiments. Some of these embodiments are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only show typical embodiments of the present disclosure and should not be considered to limit the scope of the present disclosure, and that the present disclosure may also permit other equally valid embodiments. [Brief explanation of the drawing]

[0011] [Figure 1] An exemplary processing chamber configured to perform patterning and etching of a substrate according to one embodiment described in this book is shown. [Figure 2] A flowchart of a method for patterning a film stack placed on a substrate according to one embodiment described herein is shown. [Figure 3] A flowchart of a method for patterning a film stack placed on a substrate according to one embodiment described herein is shown. [Modes for carrying out the invention]

[0012]

[0013] To facilitate understanding, the same reference numerals were used where possible to indicate identical elements common to the figures. It is assumed that elements disclosed in one embodiment may be usefully utilized in other embodiments, even without specific description.

[0013]

[0014] The embodiments of this disclosure relate to methods for patterning photoresists. The methods disclosed herein relate to pretreatment and posttreatment processes used in photoresist patterning processes, including stepwise infiltration synthesis (SIS) processes.

[0014]

[0015] In conventional resist layers, the resist material is selected from polymers to control parameters such as selectivity and line width roughness when the film stack on which the resist layer is formed is exposed to an etchant and vias or trenches are formed in the layer beneath the film stack. However, when the resist layer is selected from a polymer and the underlying layer is formed from a complex metal or amorphous compound, undercuts may form at the interface between the resist layer and the underlying layer. Conventional approaches to improve selectivity may include multiple depositions of resist layers or improvements to the polymer structure of each resist layer. However, conventional approaches typically utilize variations in the photoresist composition depending on the size of the feature intended to be patterned.

[0015]

[0016] According to the method disclosed herein, a metal oxide is formed within a photoresist layer patterned by a SIS process. A methyl-containing material is introduced into a semiconductor processing chamber in which a film stack is placed. The methyl-containing material may also include one of aluminum, hafnium, or zirconium. In one embodiment, the film stack includes a substrate, a lower layer placed on the substrate, and a patterned photoresist layer placed on the lower layer. The film stack, and thus the patterned photoresist layer, is heated, and the methyl-containing material is absorbed into the patterned photoresist layer. The processing environment is then purged, and the film stack is exposed to an oxidizing agent (such as H2O). The oxidizing agent is heated under pressure, which may form water or water vapor on the film stack. The oxidizing agent is absorbed into the patterned photoresist layer and oxidizes the absorbed methyl-containing material.

[0016]

[0017] Upon oxidation, the methyl-containing material forms a metal oxide within the patterned photoresist layer. If the methyl-containing material is a trimethylaluminum (TMA) precursor introduced into the processing environment, followed by purging and pumping, H2O is introduced into the processing environment in a single pre-etching process, i.e., without repeatedly introducing TMA before oxidizing and etching the film stack. The pre-etching process comprises one or all of the processes of the disclosed method (described in detail below) prior to etching the film stack. Advantageously, a single pre-etching process allows the metal oxide to penetrate into the photoresist layer between approximately 20 nm and 40 nm. Furthermore, the metal oxide is crosslinked across the entire thickness of the patterned photoresist. By repeating one or all of the pre-etching processes before etching the film stack, the penetration of the methyl-containing material is stopped, and consequently, the penetration of the metal oxide across the entire thickness of the photoresist layer is stopped. In some embodiments disclosed herein, the entire method, i.e., a full cycle including pre-etching and etching of the film stack, can be repeated.

[0017]

[0018] The methods described herein also improve patterning processes incorporating a SIS process by utilizing a pretreatment process, a posttreatment process, or a combination of pretreatment and posttreatment processes. In one embodiment, a pretreatment process is performed on the photoresist layer before performing the SIS process. In another embodiment, a posttreatment process is performed on the photoresist layer after performing the SIS process. In yet another embodiment, a pretreatment process is performed on the photoresist layer before performing the SIS process, and a posttreatment process is performed on the photoresist layer after performing the SIS process. The pretreatment process described herein enhances the selectivity between the photoresist layer and the underlying layer during the SIS process. The posttreatment process described herein removes metal oxides, such as aluminum oxide, from the surface of the underlying layer after the SIS process has been performed.

[0018]

[0019] The methods disclosed herein are independent of feature size. Advantageously, when metal oxides penetrate the underlying layer, the critical dimensions change by less than 1 nm, and the line width roughness changes by less than 0.4 nm. In addition, pretreatment and posttreatment methods reduce the probability of metal oxide penetration into the underlying layer by controlling the properties of the underlying layer.

[0019]

[0020] Figure 1 is a schematic cross-sectional view of a processing chamber 100, such as a dual load-lock chamber. Processing chamber 100 is illustrative, and other processing chambers may be adapted to implement the methods disclosed herein.

[0020]

[0021] In addition, the processing chamber 100 is suitable for performing deposition processes. One example of a processing chamber that may be adapted to benefit from this disclosure is the CENTRIS® Sym3® etching processing chamber, available from Applied Materials, Inc. in Santa Clara, California. The processing chamber may also be configured for deposition, particularly atomic layer deposition (ALD). An example of an ALD tool is the iSprint® ALD / CVD SSW chamber configured with a Centura® or Endura® system.

[0021]

[0022] The processing chamber 100 includes an upper chamber space 120 for transporting and processing substrates 138, and a lower chamber space 110 for transporting substrates 138. The upper chamber space 120 and the lower chamber space 110 are stacked vertically and isolated from each other. Each of the lower chamber space 110 and the upper chamber space 120 may be selectively connected to two adjacent external environments (i.e., a factory interface and a transport chamber, neither shown) through two openings configured for substrate transport. Examples of substrate sizes include, among others, those with diameters of 200 mm, 250 mm, 300 mm, and 450 mm.

[0022]

[0023] The processing chamber 100 includes a chamber body 103. In one embodiment, the chamber body 103 includes an upper chamber body 121 and a lower chamber body 111 that are connected together to define a lower chamber space 120 and an upper chamber space 110. The processing chamber 100 may include a hoop assembly 144 configured to not only confine a confinement region within the upper chamber space 120 but also load and unload substrates. Although the hoop assembly 144 is described in connection with a load lock chamber having a processing space, it should be understood that the hoop assembly 144 may be utilized in any suitably adapted load lock and / or processing chamber, including those having a single processing space that preferably has a symmetrical confinement region. The processing chamber 100 may include support pins 113 for supporting the substrate 138 within the lower chamber space 110.

[0023]

[0024] The upper chamber space 120 is defined by a sidewall 124 of the upper chamber body 121, a bottom wall 123 of the upper chamber body 121, an upper wall 118 of the lower chamber body 111, and a chamber lid assembly 116. The upper chamber space 120 is suitable for patterning of material layers, formation of material layers disposed on the substrate 138, and etching. In an example not shown, it is also envisioned that one or more plasma generators may be optionally utilized to maintain plasma within the upper chamber space 120, instead of or in addition to a remote plasma source. It is envisioned that other processing chambers, including those from other manufacturers, may be adapted to implement embodiments of the present disclosure.

[0024]

[0025] The substrate support pedestal 140 is disposed in the upper chamber space 120 to support the substrate 138 during processing. A cover ring 130 is placed on the ESC 134 along the outer periphery of the substrate support pedestal 140. The cover ring 130 is configured to limit the etching gas to a desired portion of the exposed upper surface of the substrate 138 while shielding the upper surface of the substrate support pedestal 140 from the plasma environment inside the etching processing chamber 100. A lift pin (not shown) is selectively moved through the substrate support pedestal 140 to lift the substrate 138 above the substrate support pedestal 140, facilitating access to the substrate 138 by a transfer robot (not shown) or other suitable transfer mechanism.

[0025]

[0026] The substrate support pedestal 140 includes an electrostatic chuck (ESC) 134 for holding the substrate 138 during processing. The ESC 134 utilizes electrostatic attraction to hold the substrate 138 to the substrate support pedestal 140. The ESC 134 is powered by an RF power supply 154 integrated with a matching circuit 152. The ESC 134 includes an electrode 132 embedded in a dielectric. The electrode 132 is connected to the RF power supply 154 to provide a bias. The bias attracts plasma ions formed by the processing gas in the upper chamber space 120 to the ESC 134 and the substrate 138 disposed thereon. The RF power supply 154 can repeat on and off and emit pulses during the processing of the substrate 138. The plasma generator may be an RF drive coil disposed outside or inside the upper chamber space 120 and / or an RF drive electrode disposed within the substrate support pedestal 140.

[0026]

[0027] The ESC134 may include a heater located internally and connected to a power source (not shown) for heating the substrate, while the cooling base 136 supporting the ESC134 may include conduits for circulating a thermal fluid to maintain the temperature of the ESC134 and the substrate 138 placed on top of it. The ESC134 is configured to operate within a desired temperature range based on the thermal balance of the device manufactured on the substrate 138. For example, the ESC134 may be configured to maintain the substrate 138 at a temperature of approximately -25°C to approximately 150°C (e.g., approximately 50°C to approximately 100°C).

[0027]

[0028] A cooling base 136 is provided to assist in temperature control of the substrate 138. To mitigate processing drift and time, the temperature of the substrate 138 can be kept substantially constant by the cooling base 136. In one embodiment, the temperature of the substrate 138 is maintained at approximately 30°C to approximately 120°C throughout the subsequent cleaning process.

[0028]

[0029] A power supply 150 is connected to the electrodes. The power supply 150 supplies a chucking voltage of approximately 200 volts to approximately 2000 volts to the electrodes 132. The power supply 150 may also include a system controller (not shown) for controlling the operation of the electrodes 132 by guiding a DC current to the electrodes 132 for chucking and unchucking the substrate 138. The vertical tube 137 provides passages for power supplies, sensors, and other wiring used by the substrate support pedestal 140.

[0029]

[0030] The hoop assembly 144 is positioned within the upper chamber space 120 according to one embodiment of the present invention. As previously stated, the hoop assembly 144 may be used in other processing chambers and / or load lock chambers. The hoop assembly 144 has at least two functions. First, the hoop assembly 144 can be positioned vertically to enable the transfer of a substrate between the substrate support pedestal 140 and a substrate transfer device (e.g., a robot end effector) entering the upper chamber space 120. Second, the hoop assembly 144 can also be positioned to define a cylindrical confinement region 144a around the substrate 138 and the region directly above the substrate support pedestal 140 during processing, thus providing a symmetrical processing environment within the upper chamber space 120 and improving processing results. The hoop assembly 144 may be used solely to establish a symmetrical confinement region within the processing space.

[0030]

[0031] The hoop assembly 144 includes a ring-shaped hoop body 146 positioned within the upper chamber space 120. The hoop body 146 has an inner diameter larger than the diameter of the substrate support pedestal 140. The hoop body 146 is connected to a shaft 157 that extends through the chamber body 103 to a lift actuator 158. The lift actuator 158, such as a linear actuator or motor, is operable to control the vertical height of the hoop body 146 within the upper chamber space 120. In one embodiment, a bellows assembly 156 is provided to prevent leakage between the shaft 157 and the chamber body 103.

[0031]

[0032] The hoop assembly 144 also includes three or more lifting fingers (not shown) attached to the hoop body 146. The lifting fingers are configured to transport the substrate between the substrate support pedestal 140 and a substrate transport device such as a robot when the hoop assembly 144 is in the upper transport position, as shown in Figure 1.

[0032]

[0033] The hoop assembly 144 further includes a hoop 145 attached to the hoop body 146. The hoop 145 extends vertically upward from the hoop body 146. In one embodiment, the hoop 145 is a cylindrical ring having a substantially cylindrical inner wall 145a. The height 145b of the inner wall 145a is much greater than the thickness of the substrate 138, so that the inner wall 145a can confine a portion of the processing space as a cylindrical confinement region 144a around and above the substrate 138. The inner wall 145a of the hoop 145 has a diameter greater than the outer diameter of the substrate support pedestal 140. In one embodiment, the hoop 145 is tall enough to overlap the substrate support pedestal 140 simultaneously during processing.

[0033]

[0034] The gas panel 160 is connected to the chamber lid assembly 116 by a gas line 167 and supplies the process gas into the upper chamber space 120. The gas panel 160 includes one or more process gas sources 161, 162, 163, 164, and may additionally include inert gases, non-reactive gases, and reactive gases as desired. In one embodiment, the gas panel 160 is configured to supply a metal precursor such as aluminum, hafnium, or zirconium. In one embodiment, the gas panel is configured to supply trimethylaluminum (TMA). In another example, the gas panel 160 is configured to supply gas precursors and vapor stage precursors such as tetrakis(ethylmethylamide)zirconium(IV) (TEMAZr) and tetrakis(ethylmethylamide)hafnium(IV) (TEMAHf). The gas panel 160 may be adapted to include one or more gas phase precursor sources located within or connected to the gas panel 160. The gas phase precursor source vaporizes a liquid precursor supplied from a liquid precursor in fluid communication with a gas phase precursor ampoule using a thermal and / or vacuum-enhanced vaporization process. In other examples, the gas phase precursor source is a liquid injection vaporizer configured to supply a mixture of the gas phase precursor and a carrier gas to the upper chamber space 120 of the processing chamber 100. In some embodiments, the gas phase precursor source is configured to vaporize or sublimate a solid precursor.

[0034]

[0035] Additional examples of process gases that may be provided by the gas panel 160 include, but are not limited to, the following: hydrocarbon-containing gases (including methane (CH4)), silicon-containing gases such as sulfur hexafluoride (SF6), silicon chloride (SiCl4), or organosilicon-containing gases such as bis(diethylamide)silane (BDEAS), tris(dimethylamino)silane (TDMAS), bis(tert-butylamino)silane (BTBAS), hydrogen tetrafluoride (CF4), bromide (HBr), hydrocarbon-containing gases, argon gas (Ar), chlorine (Cl2), nitrogen (N2), helium (He), and oxygen gas (O2). In addition, the process gas may contain nitrogen, chlorine, fluorine, oxygen, and hydrogen-containing gases (e.g., BCl3, C2F4, C4F8, C4F6, C2F2, C2F6, C5F8, CHF3, CH2F2, CH3F, F2, NF3, NH3, CO2, SO2, CO, N2, NO2, N2O, and H2).

[0035]

[0036] Valve 166 controls the flow of processed gas from sources 161, 162, 163, and 164 of the gas panel 160, and is managed by controller 180. The flow of gas supplied from the gas panel 160 to the upper chamber space 120 may include one of the disclosed gases or combinations of gases.

[0036]

[0037] The chamber lid assembly 116 includes a nozzle 114 fluidly connected to a gas line 167. The nozzle 114 has one or more ports for introducing processing gas from sources 161, 162, 164, and 163 of the gas panel 160 into the upper chamber space 120. After the processing gas is introduced into the etching chamber 100, the gas is energized to form a plasma. Alternatively, a gas or precursor is supplied to the upper chamber space, and the precursor is pulsed under a predetermined pressure for a predetermined time, allowing the precursor to react with the substrate surface, for example, by ALD.

[0037]

[0038] One or more inductor coils or similar antennas 148 may be provided adjacent to the processing chamber 100. The antenna power supply 142 can supply power to the antenna 148 via a matching circuit 141 and inductively couple energy (such as RF energy) to the processing gas to maintain the plasma formed from the processing gas in the upper chamber space 120 of the processing chamber 100. Alternatively, or in addition to, the antenna power supply 142, processing electrodes below and / or above the substrate 138 can be used to capacitively couple RF power to the processing gas to maintain the plasma in the upper chamber space 120. The operation of the antenna power supply 142 may be controlled by a controller (e.g., controller 180) that also controls the operation of other components in the processing chamber 100.

[0038]

[0039] Controller 180 is connected to the processing chamber 100 to control its operation. For example, controller 180 is configured to control the flow of various precursor and processing gases and purge gases from a gas source during various steps of the substrate processing sequence. Controller 180 includes a processor 182, memory 184, and support circuitry 186 for processor 182 to facilitate the control of components of the processing chamber 100. Controller 180 may be one of any form of general-purpose computer processor that can be used in an industrial environment to control various chambers and subprocessors. Memory 184 stores software (source code or object code) that can be executed or called to control the operation of the processing chamber 100 in the method described herein. Memory 184 is a non-transient computer-readable medium and may be one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), or any other form of local or remote digital storage. Memory 184 contains instructions that, when executed by processor 182, facilitate the execution of method 200 (shown in Figure 2).

[0039]

[0040] To facilitate control of the processing chamber 100, the processor 182 may be any form of general-purpose computer processor or general-purpose central processing unit (CPU), each of which can be used in industrial settings such as a programmable logic control unit (PLC) to control various chambers and subprocessors. Support circuits 186 are coupled to the processor 182 to support the processor in a conventional manner. The generation of charged species, heating, and other processes are typically stored in memory 184, usually as software routines. The software routines may also be stored and / or executed by a second CPU (not shown) located remotely from the processing chamber 100 controlled by the processor 182.

[0040]

[0041] Memory 184 is in the form of a computer-readable storage medium containing instructions, which, when executed by the processor 182, facilitate the operation of the processing chamber 100. The instructions in memory 184 are in the form of a program product, such as a program that implements the method of the present disclosure. The program code may be adapted to any one of several different programming languages. In one embodiment, the present disclosure may be implemented as a program product stored in a computer-readable storage medium for use with a computer system. One or more programs in the program product define the functionality of the embodiment (including the method described herein). Exemplary computer-readable storage mediums include, but are not limited to, (i) a non-write-only storage medium on which information is stored permanently (e.g., a read-only memory device in a computer, such as a CD-ROM disk readable by a CD-ROM drive, flash memory, a ROM chip, or any type of solid non-volatile semiconductor memory), and (ii) a writable storage medium on which modifiable information is stored (e.g., a floppy disk in a disk drive or hard disk drive, or any type of solid random-access semiconductor memory). Such computer-readable storage media constitute embodiments of the present disclosure when they carry computer-readable instructions that direct the functions of the methods described herein.

[0041]

[0042] Figure 2 shows a flow diagram of method 200 for patterning a film stack. In one embodiment, the film stack is patterned by the processes of photolithography and etching. The film stack includes a substrate 138 having an underlying layer placed on top of the substrate in contact with the substrate. The film stack also includes a photoresist layer placed on top of the underlying layer in contact with the underlying layer. The photoresist layer includes one or more pattern layers. Exemplary materials for the substrate 138 include, depending on the application, silicon, silicon oxide, doped silicon, silicon germanium, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive or semiconducting materials. The substrate 138 or its surface may also be made of dielectric materials such as silicon dioxide, silicon nitride, organosilicates, and carbon-doped silicon oxide or nitride materials.

[0042]

[0043] In one embodiment, the lower layer may be a sol-gel solution or a nanoparticle solution. The first solution may contain silicon dioxide (SiO2) and / or silicon oxycarbide (SiOC). The ratio of SiO2 and SiOC in the first solution is controlled to yield a first refractive index. For example, the first solution may contain a first ratio of SiO2 or SiOC. In one embodiment, the sol-gel precursor for SiO2 may include tetramethyl orthosilicate (TMOS), methyltrimethoxysilane (MTMS), and tetraethyl orthosilicate (TEOS). The first refractive layer may contain a first material, and subsequent refractive layers may contain a second material different from the first material. A series of refractive layers of metals and / or dielectrics with various dielectric constants and refractive indices, such as a gradient anti-reflective coating (ARC), reduce glare, reflection, or blur. The refractive index of the encapsulation layer may be adjusted from greater than about 2.0 to about 1.47. An exemplary range for the refractive index of the lower layer is between about 1.5 and about 2.0, for example, about 1.75. In yet another example, the refractive index of the lower layer 301 may be between about 1.0 and about 1.5, for example, about 1.47. In yet another embodiment, the refractive index of the lower layer may be between about 1.0 and about 1.5, for example, about 1.48 or about 1.49, or between about 1.0 and about 1.5, for example, about 1.47.

[0043]

[0044] Method 200 begins in step 202 by performing a pretreatment process to reduce or prevent the penetration of metal oxides into the underlying layers of the film stack. The pretreatment process modifies the underlying layers to minimize the subsequent penetration of metal oxides into the underlying layers. In one embodiment, the pretreatment process is performed to create methyl-terminated surfaces on the underlying layers by removing hydroxyl groups from the surface of the underlying layers. As a result, the surface of the underlying layers changes from a hydrophilic surface to a hydrophobic surface. In one embodiment, a self-assembled monolayer (SAM) material is formed on the underlying layers. Various SAM materials can be advantageously utilized, but one example of such a material is formed by the deposition of hexamethyldisilazane (HMDS). In this example, the HMDS is supplied to the substrate by a vapor dropping process utilizing a carrier gas (e.g., Ar, N, a noble gas, or an inert gas) for a period of about 1 to 20 minutes, for example, about 5 to 10 minutes, at a temperature between about 70°C and about 150°C, for example, between about 100°C. The SAM material deposition process is carried out at a pressure between approximately 1 Torr and approximately 100 Torr, for example, approximately 10 Torr. The resulting SAM material enhances the selectivity between the photoresist and the underlying layer during the subsequent SIS process by modifying the surface properties and reactivity of the underlying layer surface to minimize or prevent penetration into the underlying layer during the subsequent SIS process. In one embodiment, step 202 is carried out in the same processing chamber as steps 204, 206, and 208. Alternatively, step 202 is carried out in a different processing chamber than the one in which steps 204, 206, and 208 were carried out.

[0044]

[0045] In step 204, the methyl-containing material is absorbed into the photoresist layer placed on the film stack. The methyl-containing material is supplied to the processing space of the processing chamber in which the film stack is located, for example, the upper chamber space 120 of processing chamber 100. The methyl-containing material is supplied to the processing space (e.g., the upper chamber space 120) under high pressure. In one embodiment, the methyl-containing material is a gas containing trimethylaluminum (TMA). Alternatively, the methyl-containing material can be supplied as a vapor or liquid, which can be supplied to the processing space. In one embodiment, the vapor or liquid includes (TEMAZr) or (TEMAHf). The methyl-containing material is supplied to the upper chamber space 120 at a predetermined temperature, pressure, and time. The methyl-containing material contains aluminum atoms, hydrogen atoms, and carbon atoms. In one embodiment, the methyl-containing material is supplied to the upper chamber space 120 under high pressure over a predetermined time and temperature. For example, the pressure can be from about 100 mTorr to about 20 Torr, for example, from about 1 Torr to about 10 Torr, or from about 3 Torr to about 7 Torr. The predetermined time is between about 1 second and about 45 seconds, for example, between about 10 seconds and 30 seconds. In another embodiment, the pressurized methyl-containing material is supplied to the upper chamber space 120 for about 15 seconds, or about 20 seconds, or about 30 seconds. In at least one example, the predetermined temperature is between about 0 degrees Celsius and about 150 degrees Celsius, for example, between about 50 degrees Celsius and about 100 degrees Celsius, for example, between about 75 degrees Celsius and about 100 degrees Celsius.

[0045]

[0046] The methyl-containing material is absorbed into the patterned photoresist layer by heating the upper chamber space 120, allowing the methyl-containing material to diffuse into the patterned layer of the photoresist layer. The heat also allows for the formation of gaps or spaces between polymers through which the methyl-containing material can penetrate when under pressure. The polymers within the photoresist layer are sufficiently dispersed so that the methyl-containing material can diffuse through the upper surface of the photoresist layer and occupy the spaces between the polymers. The photoresist layer is saturated with the methyl-containing material. Thus, the methyl-containing material is trapped between the top and bottom surfaces of the photoresist layer. In other words, the methyl-containing material is absorbed and uniformly dispersed throughout the entire thickness of the photoresist layer, the thickness being defined as the distance between the top and bottom surfaces of the photoresist layer.

[0046]

[0047] In step 206, any excess or unbound methyl-containing material in the processing space is purged. For example, a purge gas is introduced into the upper chamber space 120 for about 20 seconds. After about 20 seconds, the flow of the purge gas is stopped, and the purge gas, along with any excess or unbound residual methyl-containing material, is exhausted from the upper chamber space 120 for about 20 seconds using one or more dedicated vacuum pumps. In one embodiment, one or more dedicated vacuum pumps (not shown) are part of a vacuum pump system (not shown). The purge gas is a non-reactive gas, which in one example may be N2. In another embodiment, the purge gas is a chemically inert gas such as Ar or He. Purging makes it possible to substantially eliminate methyl-containing material from the upper surface of the photoresist layer in preparation for oxidation.

[0047]

[0048] In step 208, the methyl-containing layer is oxidized to form a treated photoresist layer. An oxidizing agent containing oxygen and hydrogen atoms is introduced into the upper chamber space 120. In one embodiment, the oxidizing agent is water and can be supplied to the upper chamber space 120 as a liquid or gas. As the methyl-containing material interacts with the oxidizing agent during the oxidation process, metal oxides and by-product gases are formed within the photoresist layer. The by-product gases diffuse from the photoresist layer through the surface of the patterned layer, including the upper surface. Since the upper surface of the photoresist layer is in contact with the upper chamber space 120 and the material contained in the lower layer is denser than any gas in the upper chamber space 120, there is virtually no diffusion of by-product gases through the lower layer.

[0048]

[0049] If the methyl-containing material is TMA, then alumina (AlO x ) is a metal oxide produced, and the by-product gas 328 is methane. In one embodiment, AlO x This can be Al2O3, Al2O, AlO2, AlO, or AlO. Alternatively, if the methyl-containing material is TEMAZr, oxidation forms a metal oxide in the photoresist layer as ZrOx (e.g., ZrO2, ZrO). If the methyl-containing material is TEMAHf, oxidation of the methyl-containing material generates HfOx, such as HfO2, in the photoresist layer. The concentration of the metal oxide is between approximately 30% and 60% of the volume of the photoresist layer. TEMAZr and TEMAHf penetrate the photoresist layer, but not to the same extent as TMA, which penetrates to the entire thickness of the photoresist layer. TEMAZr and TEMAHf penetrate closer to the top surface of the photoresist layer, forming a crust-like layer containing TEMAZr and / or TEMAHf together with the polymer adjacent to the top surface, and a layer of polymer adjacent to the bottom surface. For example, TEMAZr and TEMAHf can penetrate into a photoresist layer of about 0.05 nm to about 2 nm, for example, about 1 nm or about 1.5 nm. Thus, the polymer is formed over the entire remaining thickness of the photoresist layer. Advantageously, the selectivity during subsequent etching of the film stack is AlO xCompared to ZrOx or HfOx, higher 。

[0049]

[0050] The photoresist layer is exposed to an oxidizing agent at a predetermined pressure, temperature, and time. The oxidizing agent is supplied to the processing space of the processing chamber under high pressure. For example, the oxidizing agent can be supplied to the upper chamber space 120 (i.e., the processing space) at a pressure between approximately 100 mTorr and approximately 10 Torr, for example between approximately 1 Torr and approximately 10 Torr, or between approximately 3 Torr and approximately 7 Torr. The temperature at which the oxidizing agent is supplied to the processing space is between approximately 50°C and approximately 100°C, for example between approximately 75°C and approximately 100°C.

[0050]

[0051] In one embodiment, the predetermined time for which the oxidizing agent is supplied to the upper chamber space 120 is between approximately 1 second and approximately 400 seconds. The hydrolysis reaction oxidizes the methyl-containing material in the photoresist layer over the predetermined time. In another example, the predetermined time is between approximately 240 seconds and approximately 350 seconds, for example, approximately 270 seconds, or approximately 300 seconds, or approximately 330 seconds. The predetermined time allows the oxidation process to occur throughout the entire photoresist layer, and the metal oxide to be uniformly dispersed and formed between the top and bottom surfaces. If the photoresist layer is exposed to the oxidation source for less than the predetermined time, a layer of alumina may form near the top surface of the photoresist layer without forming throughout the entire photoresist layer, and thus a layer of polymer may be formed close to the bottom surface. If the photoresist layer is exposed to an oxidation source such as an oxidizing agent for less than the predetermined time, the metal oxide may concentrate on the top surface of the mask, creating a crust, despite the methyl-containing material extending through the thickness of the photoresist layer.

[0051]

[0052] The metal oxide formed in step 208 contains metal atoms and oxygen atoms. In one embodiment, when the methyl-containing material is TMA, the metal atoms are aluminum, and therefore the metal oxide is alumina (AlO x ) is formed. Alternatively, if the methyl-containing material is TEMAZr, the metal oxide formed is zirconium oxide (ZrO xThe metal atom is zirconium, so that the result is ). In yet another example, if TEMAHf is a methyl-containing material, the metal oxide that is formed is hafnium oxide (HfO x ) and the metal atom is hafnium.

[0052]

[0053] In step 210, the film stack having the processed patterned photoresist layer is etched. For example, the film stack is exposed to an etchant which may be dry etching or wet etching. In one embodiment, the film stack is exposed to an etchant from a plasma formed from one of the above-mentioned processing gases, such as a fluorine-containing gas or a carbon-fluorine-containing gas. Upon exposure to the plasma, as detailed above, components from the processing gas, including ions, neutrons, protons, and radicals, are generated when the processing gas is separated by the application of an electric field generated by an RF generator or DC power supply. Advantageously, the metal oxide formed in step 208 improves the etching selectivity in step 210, as well as the pretreatment process in step 202. Optionally, in step 212, method 200 may return to step 202, in which another photoresist layer 302 is deposited, the film stack 300 is pretreated again, and exposed to a methyl-containing material.

[0053]

[0054] Figure 3 shows a flow diagram of method 300 for patterning a film stack. In one embodiment, the film stack is patterned by the processes of photolithography and etching. Similar to the embodiment described with respect to Figure 2, the film stack includes a substrate 138 having an underlying layer that is placed on and in contact with the substrate. The film stack also includes a photoresist layer placed on the underlying layer in contact with the underlying layer. The photoresist layer includes one or more pattern layers. Exemplary materials for the substrate 138 include, depending on the application, silicon, silicon oxide, doped silicon, silicon germanium, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive or semiconducting materials. The substrate 138 or its surface may also be made of dielectric materials such as silicon dioxide, silicon nitride, organosilicates, and carbon-doped silicon oxide or nitride materials.

[0054]

[0055] In one embodiment, the lower layer may be a sol-gel solution or a nanoparticle solution. The first solution may contain silicon dioxide (SiO2) and / or silicon oxycarbide (SiOC). The ratio of SiO2 and SiOC in the first solution is controlled to yield a first refractive index. For example, the first solution may contain a first ratio of SiO2 or SiOC. In one embodiment, the sol-gel precursor for SiO2 may include tetramethyl orthosilicate (TMOS), methyltrimethoxysilane (MTMS), and tetraethyl orthosilicate (TEOS). The first refractive layer may contain a first material, and subsequent refractive layers may contain a second material different from the first material. A series of refractive layers of metals and / or dielectrics with various dielectric constants and refractive indices, such as a gradient anti-reflective coating (ARC), reduce glare, reflection, or blurring. The refractive index of the encapsulation layer may be adjusted from greater than about 2.0 to about 1.47. An exemplary range for the refractive index of the lower layer is between about 1.5 and about 2.0, for example, about 1.75. In yet another example, the refractive index of the lower layer 301 may be between about 1.0 and about 1.5, for example, about 1.47. In yet another embodiment, the refractive index of the lower layer may be between about 1.0 and about 1.5, for example, about 1.48 or about 1.49, or between about 1.0 and about 1.5, for example, about 1.47.

[0055]

[0056] Method 300 begins with step 204, proceeds to step 206, and then proceeds to step 208, which is described in detail with respect to Figure 2. In step 302, a post-treatment process is performed to remove metal oxides from the underlying layers of the film stack that may be formed during the SIS process (steps 204, 206, and 208). If metal oxides are present in undesirable areas of the underlying layers, for example, on trenches where the presence of metal oxides leads to bridge defects, the post-treatment process is performed to remove the metal oxides from the underlying surface.

[0056]

[0057] In one embodiment, post-treatment process 302 is a chemical etching process capable of selectively removing materials such as metal oxide materials from the underlying surface. For example, post-treatment process 302 is a wet acid etching process. Examples of acids suitable for carrying out the post-treatment process include, but are not limited to, hydrochloric acid and hydrofluoric acid. Other materials suitable for use in post-treatment process 302 include ferric chloride, sodium hydroxide, potassium hydroxide, or other materials suitable for removing metal oxide materials from the underlying surface. After performing post-treatment process 302, the film stack is etched in step 210.

[0057]

[0058] In certain embodiments, pretreatment step 202 is combined with posttreatment step 302. In this embodiment, the method begins with step 202, in which a pretreatment process is performed to modify the surface of the underlying layer. Next, the SIS process is performed by sequentially executing steps 204, 206, and 208. After step 208, posttreatment step 302 is performed to remove metal oxides from the surface of the underlying layer. After the posttreatment process, step 210 is performed to etch the film stack. Although the embodiments described above have been described in relation to metal oxide-containing photoresist materials, the pretreatment and posttreatment processes may, advantageously, be used in conjunction with non-metallic SIS processing processes. Similarly, although the embodiments described above have been described in relation to polymer photoresist materials, the embodiments described herein may, advantageously, be implemented using metallic photoresist materials and chemically amplified resist materials.

[0058]

[0059] The above description applies to embodiments of the present disclosure, but other embodiments and further embodiments of the present disclosure may be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the following claims.

Claims

1. A method for processing layers of a film stack, Pre-treatment of the surface of the lower layer of the film stack formed on the substrate, A metal oxide is formed within the photoresist layer of a film stack by heating a methyl-containing material in a processing environment near the film stack, wherein the film stack includes the photoresist layer disposed on and in contact with the lower layer, and the lower layer disposed on a substrate, and the metal oxide is formed accordingly. Etching the film stack including the photoresist layer into which the metal oxide has been implanted. Methods that include...

2. The methyl-containing material is absorbed through the upper surface of the photoresist layer. The method according to claim 1, further comprising:

3. The method according to claim 2, wherein the methyl-containing material is absorbed over the entire thickness of the photoresist layer, and the metal oxide is alumina.

4. Maintaining the photoresist layer at a pressure that the methyl-containing material can absorb over the entire thickness of the photoresist layer. The method according to claim 1, further comprising:

5. The method according to claim 1, wherein pre-treating the surface of the lower layer includes forming a SAM material on the surface of the lower layer.

6. The method according to claim 5, wherein the SAM material is formed by exposing the surface of the lower layer to hexamethyldisilazane.

7. Oxidizing the methyl-containing material within the photoresist layer The method according to claim 1, further comprising:

8. Before oxidizing the methyl-containing material, the processing environment for the methyl-containing material is purged. The method according to claim 1, further comprising:

9. Oxidizing the methyl-containing material within the photoresist layer, The substantially entirety of the methyl-containing material is converted to alumina. The method according to claim 1, further comprising:

10. The method according to claim 9, wherein the film stack is etched using a fluorine-containing gas or a carbon-fluorine-containing gas.

11. A method for processing layers of a film stack, A metal oxide is formed within the photoresist layer of a film stack by heating a methyl-containing material in a processing environment near the film stack, wherein the film stack includes the photoresist layer disposed on and in contact with the lower layer, and the lower layer disposed on a substrate, and the metal oxide is formed accordingly. In order to remove the metal oxide from the lower layer, a post-treatment process is performed on the surface of the lower layer, Etching the film stack containing the metal oxide and the photoresist layer Methods that include...

12. The method according to claim 11, wherein the post-processing step includes a wet etching step.

13. The method according to claim 12, wherein the wet etching process includes exposing the surface of the underlying layer to hydrochloric acid or hydrofluoric acid.

14. Oxidizing the methyl-containing material within the photoresist layer The method according to claim 11, further comprising:

15. Before oxidizing the methyl-containing material, the processing environment for the methyl-containing material is purged. The method according to claim 11, further comprising:

16. The methyl-containing material in the photoresist layer is oxidized for a predetermined time between approximately 1 second and approximately 400 seconds. The method according to claim 15, further comprising:

17. Oxidizing the methyl-containing material within the photoresist layer, The substantially entirety of the methyl-containing material is converted to alumina. It further includes, The aforementioned film stack is etched using a fluorine-containing gas or a carbon-fluorine-containing gas. The method according to claim 11.

18. A substrate processing method, The substrate, including the lower layer and the photoresist layer, is placed inside the processing chamber. In order to form SAM material on the surface of the lower layer, a pretreatment process is performed on the surface of the lower layer, Exposing the aforementioned photoresist layer to a methyl-containing material, Purging the methyl-containing material from the processing chamber, The methyl-containing material is oxidized to form a treated photoresist, In order to remove the metal oxide material from the surface of the lower layer, a post-treatment process is performed on the surface of the lower layer. Etching the photoresist layer and the lower layer Methods that include...

19. The method according to claim 18, wherein the surface of the lower layer after the pretreatment process is hydrophobic.

20. The method according to claim 19, wherein the surface of the lower layer after the post-processing step substantially does not contain the metal oxide material.

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