Dry developing device and method of forming a dry pattern of photoresist using the same

Abstract

One embodiment of the present invention provides a dry development apparatus and a method for forming a dry pattern of a photoresist using the same. Since the method for forming a dry pattern of a photoresist according to one embodiment of the present invention is a dry process, it has the effect of preventing the pattern collapse of a nanopattern that may occur in a wet development process.

Description

Technology Field

[0001] The present invention relates to a dry developing apparatus and a method for forming a dry pattern of a photoresist using said apparatus and radical plasma. Background Technology

[0002] Due to the miniaturization of the critical dimension (CD) of semiconductor patterns, the implementation of nanometer-scale patterns in the patterning process is required. To manufacture semiconductor devices with fine patterns, numerous unit processes such as photolithography, deposition, and etching are performed.

[0003] At this time, in the conventional photolithography process, a thick organic photoresist (PR) is used to form a photoresist pattern through wet development.

[0004] However, the above wet photoresist process has a problem in that it is difficult to implement patterns with a line width of less than 30 nm.

[0005] At this time, the reason why the above wet photoresist process is difficult to form fine patterns is that the aspect ratio increases due to the thick thickness and decreasing line width, and during the wet development process, the pattern collapses due to capillary force while the developer evaporates.

[0006] The present invention provides a dry development apparatus using radical plasma and a method for forming a dry photoresist pattern using the same to suppress the pattern collapse phenomenon of a nanopattern caused by surface tension that may occur during the wet development process described above. Prior art literature

[0007] Republic of Korea Registered Patent No. 10-1662702 The problem to be solved

[0008] The technical problem to be solved by the present invention is to provide a dry developing apparatus and a method for forming a dry pattern of photoresist using the same.

[0009] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0010] To achieve the above technical problem, one embodiment of the present invention provides a method for forming a dry pattern of a photoresist.

[0011] A method for forming a dry pattern of a photoresist according to one embodiment of the present invention comprises the step of depositing a photosensitive photoresist on a substrate, and then exposing the photoresist to a light source to form a coating layer on the substrate including an exposed portion and a non-exposed portion;

[0012] A step of installing the substrate having the above-mentioned coating layer on a second electrode located at the bottom of a dry developing device equipped with a radical conversion device;

[0013] A step of injecting a plasma generating gas into the above dry developing device and generating plasma by applying power to a first electrode located at the top of the dry developing device; and

[0014] The method may include a step of forming a pattern by selectively removing non-exposed portions on the substrate by exposing the substrate, on which a coating layer formed on the second electrode is installed, to the radical plasma after converting the above plasma into a radical plasma by a radical conversion device.

[0015] In addition, according to one embodiment of the present invention, the photosensitive photoresist may include a metal-organic cluster type photoresist, an organic hydrogen silses quioxane-based photoresist, an organic-inorganic hybrid photoresist, or a Keggin cluster type photoresist.

[0016] In addition, according to one embodiment of the present invention, in the step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device in which a radical conversion device is installed, the radical conversion device may be a conductive substrate having a mesh-type or circular through-hole having a grid pattern.

[0017] In addition, according to one embodiment of the present invention, in the step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device in which a radical conversion device is installed, the diameter of the through hole of the radical conversion device may be 50 μm to 500 μm.

[0018] In addition, according to one embodiment of the present invention, in the step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device in which a radical conversion device is installed, the radical conversion device may include one or two.

[0019] In addition, according to one embodiment of the present invention, in the step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device in which a radical conversion device is installed, the radical conversion grid may be electrically grounded.

[0020] In addition, according to one embodiment of the present invention, in the step of generating the plasma,

[0021] The above plasma generating gas is Cl2, BCl3, HBr, SiCl4, ClF3, HCl, CHF3, SF6, NF3, CF4, CF4, C x F y Hz (Here, x is a natural number from 1 to 6, y is a natural number from 4 to 8, and z is a natural number from 1 to 4), one or more reactive gases selected from the group consisting of O2, N2 and H2, and one or more inert gases selected from the group consisting of Ar, Ne, He and Xe may be used.

[0022] In addition, according to one embodiment of the present invention, in the step of generating the plasma, the power applied to the first electrode may be 30 W to 5 kW.

[0023] In addition, according to one embodiment of the present invention, in the step of forming the pattern, plasma generated at the upper part of the dry developing device moves to a substrate on a second electrode located at the lower part, and passes through a through hole of the radical conversion device so that plasma ions can be converted into electrically neutral radical plasma.

[0024] In addition, according to one embodiment of the present invention, in the step of forming the pattern, the temperature of the second electrode applied to the device during the dry development process is -30 o C to 120 o It could be C.

[0025] In addition, according to one embodiment of the present invention, in the step of forming the pattern, the pressure applied to the device during the dry development process may be 3 mTorr to 300 mTorr.

[0027] To achieve the above technical problem, another embodiment of the present invention provides a dry developing device.

[0028] The dry developing apparatus according to one embodiment of the present invention may include: a chamber having an internal space for processing a substrate; a light source unit located on one side of the upper portion of the chamber and irradiating light onto a substrate coated with a photoresist pattern; a plasma generating unit located on the upper portion of the chamber and including a first electrode for generating plasma and a gas inlet for injecting the plasma generating gas; a pattern forming unit located on the lower portion of the chamber and including a second electrode on which a substrate is installed and a pump for discharging residual gas; and a radical conversion unit located between the plasma generating unit and the pattern forming unit and including a radical conversion device for converting the plasma generated by the plasma generating unit into radical plasma.

[0029] In addition, according to one embodiment of the present invention, in the radical conversion unit, the radical conversion device may include a substrate having a mesh-shaped or circular through hole having a grid pattern.

[0030] In addition, according to one embodiment of the present invention, in the radical conversion unit, the diameter of the through hole of the radical conversion device may be 50 μm to 500 μm.

[0031] In addition, according to one embodiment of the present invention, the radical conversion unit may include one or two radical conversion grids.

[0032] In addition, according to one embodiment of the present invention, in the radical conversion unit, the radical conversion grid may be electrically grounded. Effects of the invention

[0033] The photoresist dry pattern forming method according to one embodiment of the present invention is a dry process, so it has the effect of preventing the pattern collapse phenomenon of nano-patterns that may occur in the wet development process.

[0034] In addition, the dry developing device according to one embodiment of the present invention converts plasma into radical plasma by a radical conversion device when forming a pattern, thereby leaving the photosensitive parts within the film and selectively removing the unexposed parts, making it easier to remove residue compared to wet developing.

[0035] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims. Brief explanation of the drawing

[0036] FIG. 1 is a flowchart illustrating a method for forming a dry pattern of photoresist. Figure 2 is a schematic diagram showing a dry developing apparatus. Figure 3 is a schematic diagram showing a radical conversion device. Figure 4 is an SEM image of a pattern in a Tin OH film after performing a lithography process using an ArF scanner. Figure 5 is an SEM image showing a Tin OH photoresist developed into a negative tone after dry development using Cl2 radical plasma. Figure 6 is an example diagram showing the thickness of the exposed / unexposed TinOH film according to the dry development process time using Cl2 radical plasma. Figure 7 is a graph showing the XPS analysis results of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma. Figure 8 is a graph showing the measurement results of high-resolution O1s XPS spectra of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma. Figure 9 is a graph showing the measurement results of high-resolution C1s XPS spectra of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma. Figure 10 is a graph showing the measurement results of high resolution Cl 2p XPS spectra of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma. Figure 11 is a graph showing ln (development rate) at different temperatures of the substrate (second electrode) to calculate the activation energy of the exposed / unexposed TinOH during dry development using Cl2 radical plasma. Figure 12 shows a surface image of a TinOH photoresist pattern when the dry development process is performed with radical plasma and when the dry development process is performed by direct exposure to ICP plasma. Figure 13 is a surface image showing a TinOH photoresist line and space pattern after dry development using radical plasma (left) and a TinOH photoresist line and space pattern after wet development using developer (right). Figure 14 is a graph showing the dry development rate (blue) of the exposed Tin OH and the unexposed Tin OH at process pressures of 8 mtorr to 60 mtorr. Specific details for implementing the invention

[0037] The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0038] Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0039] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0041] Hereinafter, the present invention will be described with reference to the drawings presented in this specification. For reference, the drawings may be partially exaggerated to illustrate the features of the present invention. In such cases, it is preferable to interpret them in light of the entire intent of this specification.

[0043] A method for forming a dry photoresist pattern according to one embodiment of the present invention is described.

[0044] The present invention provides a method for forming a dry photoresist pattern using a dry development device.

[0045] FIG. 1 is a flowchart illustrating a method for forming a dry pattern of photoresist.

[0046] Referring to FIG. 1, a method for forming a dry pattern of a photoresist according to an embodiment of the present invention may include: a step (S100) of depositing a photosensitive photoresist on a substrate, and then exposing the photoresist to a light source to form a coating layer on the substrate including an exposed portion and a non-exposed portion; a step (S200) of installing the substrate having the coating layer on a second electrode located at the bottom of a dry developing device equipped with a radical conversion device; a step (S300) of injecting a plasma generating gas into the dry developing device and applying power to a first electrode located at the top of the dry developing device to generate plasma; and a step (S400) of converting the plasma into a radical plasma by a radical conversion device, and then exposing the substrate having the coating layer installed on the second electrode to the radical plasma to selectively remove the non-exposed portion on the substrate to form a pattern.

[0047] In the first step, the method may include the step of exposing the photoresist to a light source to form a coating layer on the substrate comprising an exposed portion and a non-exposed portion. (S100)

[0048] The photosensitive photoresist of the present invention may include a metal-organic cluster type photoresist, an organic hydrogen silses quioxane-based photoresist, an organic-inorganic hybrid photoresist, or a Keggin cluster type photoresist, and may be used without limitation when an exposed area and a non-exposed area are formed on a substrate.

[0049] At this time, the deposition on the substrate can be performed by uniformly applying photoresist to the substrate using processes such as spin coating, evaporation, ALD, CVD, PEALD, PECVD, MOCVD, etc., and then forming a coating layer by performing additional processes such as soft bake and EBR (edge ​​bead removal), but any photoresist deposition method used by a person skilled in the art can be used without limitation.

[0050] At this time, the light source may be a light source having a specific wavelength (6 nm to 500 nm), and may be exposed to a light source, electron beam, X-ray, etc., for example; KrF (248 nm) stepper, ArF (193 nm) dry scanner, ArF (193 nm) immersion scanner, EUV (13.5 nm) scanner, BEUV (6.7 nm), electron beam (e-beam lithography), X-ray, etc. may be used.

[0051] At this time, the present invention forms a pattern on the photoresist coated on the substrate by exposing it to the light source, and does not perform a development process such as a wet development process (a process of removing non-exposed areas and leaving exposed areas using a developer).

[0053] In the second step, the method may include the step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device equipped with a radical conversion device. (S200)

[0054] At this time, the radical conversion device can be placed between the substrate chucks of the first electrode and the second electrode.

[0055] At this time, the radical conversion device is characterized by being a conductive substrate having a mesh-type or circular through-hole with a grid pattern as shown in FIG. 3.

[0056] At this time, the diameter of the through hole of the radical conversion device may be 50 μm to 500 μm, the diameter of the through hole may vary depending on the process pressure, and the spacing may vary to control the density of the radical used in the process.

[0057] In addition, the radical conversion device may include one or two.

[0058] At this time, for example, if the radical conversion device includes two or more substrates, the through holes of the device may be arranged in an alternating manner so that energetic particles do not come into direct contact with the substrates.

[0059] At this time, when the radical conversion device includes two or more substrates, the reason the through holes of the device are arranged in an alternating manner is that if ions generated within the plasma are directly incident, surface damage to the photoresist occurs.

[0060] In this case, in the case of a grid in which the radical converter consists of two conductive meshes, the first radical converter (mesh) that comes into direct contact with the plasma is in a floating state that is electrically insulated from the chamber, and the second radical converter (mesh) is in an electrically grounded state.

[0061] On the other hand, if it consists of a single radical converter (mesh), it can be configured to be electrically grounded.

[0063] In the third step, the method may include the step of injecting a plasma generating gas into the dry developing device and applying power to a first electrode located at the top of the dry developing device to generate plasma. (S300)

[0064] At this time, the plasma generating gas is Cl2, BCl3, HBr, SiCl4, ClF3, HCl, CHF3, SF6, NF3, CF4, CF4, C x F y H z (Here, x is a natural number from 1 to 6, y is a natural number from 4 to 8, and z is a natural number from 1 to 4), one or more reactive gases selected from the group consisting of O2, N2 and H2, and one or more inert gases selected from the group consisting of Ar, Ne, He and Xe may be used.

[0065] At this time, the power applied to the first electrode during the dry development process may be 30 W to 5 kW.

[0066] At this time, if the power applied to the first electrode is less than 30 W, there may be a problem in that the coating layer is not removed because the plasma density is low and the number of radicals formed is small, and if it is 5 kW or more, there may be a problem in that the density of the generated radicals becomes very high and both the exposed and non-exposed photoresist are removed.

[0068] In the fourth step, the method may include the step of forming a pattern by selectively removing unexposed portions on the substrate by exposing the substrate, on which a coating layer formed on the second electrode is installed, to the radical plasma after converting the plasma into a radical plasma by a radical conversion device. (S400)

[0069] At this time, the plasma generated at the upper part of the dry developing device moves to a substrate on the second electrode located at the lower part, and passes through the through hole of the radical conversion device so that the plasma ions can be converted into electrically neutral radical plasma.

[0070] At this time, the radical plasma refers to a plasma that can exclude ions and particles having excessive energy and charge within the formed plasma and expose only the reactive radicals to the substrate after injecting a reactive gas into the chamber and discharging to form a plasma.

[0071] At this time, neutral and chemically reactive radicals can be exposed to the photoresist pattern on the substrate through a dry developing device mounted between the first electrode and the second electrode.

[0072] For example, the radical source in this case may be a combination of an ICP source and a dry developing device, a combination of a CCP source and a dry developing device, etc.

[0073] In addition, the pressure applied to the device during the above dry development process may be 3 mTorr to 300 mTorr.

[0074] At this time, if the pressure applied to the device during the above dry development process is less than 3 mTorr, there may be a problem with the generated phosphorus, and if it exceeds 300 mTorr, plasma discharge may be impossible, and there may be a problem with radical formation.

[0075] In addition, the temperature of the second electrode applied to the device during the above dry developing process is -30 o C to 120 o It could be C.

[0076] At this time, the temperature of the second electrode applied to the device during the above dry developing process is -30 o If C is less than 120, there may be a problem where the etching rate of the non-exposed area becomes very low, and 120 o If C is exceeded, there may be a problem where the non-exposed area is not removed by radicals.

[0077] At this point, the photoresist in the non-exposed area is completely removed by radical plasma, and the photoresist in the exposed area remains with the pattern formed, at which point the process can be terminated.

[0078] Specifically, in the step of removing the non-exposed parts and leaving the exposed parts, if the non-exposed parts are not all removed in a single step, a radical plasma dry development process can be carried out through multiple steps.

[0079] At this time, for example, dry development can be performed for 15 minutes with Cl2 radical plasma (1 step) and dry development can be performed for 2 minutes with CF4 radical plasma (2 step) to remove only the photoresist in the non-exposed area.

[0080] Thus, the dry pattern forming method of the photoresist of the present invention, compared to wet development, allows for easier removal of residues through dry development using radical plasma, and in the case of patterns with a small line width (CD) and high aspect ratio, it is possible to suppress pattern collapse caused by capillary force generated when liquid chemical is dried.

[0082] A dry developing apparatus according to another embodiment of the present invention is described.

[0083] Figure 2 is a schematic diagram showing a dry developing apparatus.

[0084] Referring to FIG. 2, a dry developing device according to one embodiment of the present invention is,

[0085] The apparatus may include: a chamber (100) having an internal space for processing a substrate; a light source unit (200) located on one side of the upper portion of the chamber and irradiating light onto a substrate coated with a photoresist pattern; a plasma generation unit (300) located on the upper portion of the chamber and including a first electrode for generating plasma and a gas inlet for injecting the plasma generating gas; a pattern forming unit (400) located on the lower portion of the chamber and including a second electrode on which a substrate is installed and a pump for discharging residual gas; and a radical conversion unit (500) located between the plasma generation unit and the pattern forming unit and including a radical conversion device for converting the plasma generated in the plasma generation unit into radical plasma.

[0086] FIG. 2 is a schematic diagram of a radical plasma dry development apparatus having an ICP source generator.

[0087] Referring to FIG. 2, a radical plasma dry development device may be composed of a chamber, a plasma generation unit, a pattern forming unit, and a radical conversion unit.

[0088] At this time, the chamber (100) of the present invention can be used without restriction on type if it is a vacuum chamber having an internal space for processing a substrate.

[0089] At this time, the light source unit (200) of the present invention is located on one side of the upper part of the chamber and can irradiate light onto a substrate coated with a photoresist pattern.

[0090] At this time, the light source may be a light source having a specific wavelength (6 nm to 500 nm), and may be exposed to a light source, electron beam, X-ray, etc., and for example, a KrF (248 nm) stepper, ArF (193 nm) dry scanner, ArF (193 nm) immersion scanner, EUV (13.5 nm) scanner, BEUV (6.7 nm), electron beam (e-beam lithography), X-ray, etc. may be used.

[0091] At this time, the plasma generating unit (300) of the present invention is located at the top of the chamber and may include a first electrode that generates plasma and a gas inlet into which the plasma generating gas is injected.

[0092] At this time, the first electrode is a source plasma generator, and a remote plasma source including ICP (inductively coupled plasma), CCP (capacitively coupled plasma), ECR (electron cyclotron resonance), etc. must be used.

[0093] At this time, a plasma source capable of suppressing charged particles that can damage the photoresist on the substrate and extracting only chemically reactive radicals must be used.

[0094] For example, the plasma generating gas is Cl2, BCl3, HBr, SiCl4, ClF3, HCl, CHF3, SF6, NF3, CF4, CF4, C x F y H z(Here, x is a natural number from 1 to 6, y is a natural number from 4 to 8, and z is a natural number from 1 to 4), one or more reactive gases selected from the group consisting of O2, N2 and H2, and one or more inert gases selected from the group consisting of Ar, Ne, He and Xe may be used.

[0095] At this time, the gas supply unit may supply a reactive discharge gas capable of forming radicals that react with the photoresist, or supply an inert gas for controlling plasma density.

[0096] At this time, the power applied to the first electrode during the dry development process may be 30 W to 5 kW.

[0097] At this time, the pattern forming unit (400) of the present invention may include a second electrode located at the bottom of the chamber, on which a substrate is installed, and a pump for discharging residual gas.

[0098] At this time, the second electrode is an electrode that supports the substrate, and the temperature can be controlled during the process, and it can be electrically grounded or have a DC / RF voltage applied.

[0099] At this time, the temperature of the second electrode applied to the device during the dry developing process is -30 o C to 120 o It could be C.

[0100] At this time, the second electrode voltage may be grounded, or a -DC voltage or an RF voltage may be applied.

[0101] At this time, the radical conversion unit (500) of the present invention may include a radical conversion device positioned between the plasma generation unit and the pattern forming unit, which converts the plasma generated from the plasma generation unit into radical plasma.

[0102] At this time, the radical conversion device can be placed between the substrate chucks of the first electrode and the second electrode.

[0103] At this time, the radical conversion device is characterized by being a conductive substrate having a mesh-type or circular through-hole with a grid pattern as shown in FIG. 3.

[0104] At this time, the above radical conversion device can be used without restriction if the material is conductive and can be grounded, for example, stainless steel or graphite can be used.

[0105] At this time, the diameter of the through hole of the radical conversion device may be 50 μm to 500 μm, the diameter of the through hole may vary depending on the process pressure, and the spacing may vary to control the density of the radical used in the process.

[0106] In addition, the radical conversion device may include one or two.

[0107] At this time, for example, if the radical conversion device includes two or more substrates, the through holes of the device may be arranged in an alternating manner so that energetic particles do not come into direct contact with the substrates.

[0108] At this time, when the radical conversion device includes two or more substrates, the reason the through holes of the device are arranged in an alternating manner is that if ions generated within the plasma are directly incident, surface damage to the photoresist occurs.

[0109] In this case, in the case of a grid in which the radical converter consists of two conductive meshes, the first radical converter (mesh) that comes into direct contact with the plasma is in a floating state that is electrically insulated from the chamber, and the second radical converter (mesh) is in an electrically grounded state.

[0110] On the other hand, if it consists of a single radical converter (mesh), it can be configured to be electrically grounded.

[0111] At this time, the radical conversion device of the present invention can exclude charged particles (electrons / ions), etc., within the plasma and extract only chemically reactive neutral radicals.

[0112] That is, the radical conversion device allows the plasma generated at the top of the dry development device to move to a substrate on a second electrode located at the bottom, and passes through the through hole of the radical conversion device so that the plasma ions are converted into electrically neutral radical plasma.

[0113] At this time, the principle for converting the above plasma ions into electrically neutral radical plasma is that when plasma ions with a very high energy level (10 to 30 eV) pass through a grounded radical conversion device and receive electrons, they become neutralized and can form a radical plasma that is more chemically reactive than gas molecules.

[0114] In addition, the dry developing device according to one embodiment of the present invention converts plasma into radical plasma by a radical conversion device when forming a pattern, thereby leaving the photosensitive parts within the film and selectively removing the unexposed parts, making it easier to remove residue compared to wet developing.

[0116] The present invention will be explained in more detail below through manufacturing examples and experimental examples. These manufacturing examples and experimental examples are solely for the purpose of illustrating the present invention, and the scope of the present invention is not limited by these manufacturing examples and experimental examples.

[0118] Example: Photoresist dry pattern formation

[0119] First, among organo-metallic photoresists, Tin OH, a Tin (Sn)-based metal oxo cluster photoresist, was spin-coated onto a substrate and soft-baked to form a photoresist thin film.

[0120] At this time, a lithography process was performed using an ArF dry scanner (193nm light source), and a patterned photoresist thin film was formed by performing a post-exposure bake after the lithography process.

[0121] At this time, as the photoreaction proceeds and butyl groups are removed, the thickness of the photoresist film in the exposed area decreases, while the thickness in the unexposed area remains the same.

[0122] Next, the substrate was placed on the second electrode inside the radical plasma dry development chamber.

[0123] At this time, the grid mounted inside the dry process chamber is a 1-mesh grid, and the mesh is electrically grounded.

[0124] Next, a radical plasma was formed by injecting process gas Cl2 at a substrate temperature of -10 °C, a process pressure of 70 mTorr, and an ICP source power of 400 W (13.56 MHz), and then the substrate with the patterned photoresist film was exposed to the plasma to perform radical dry development for 30 minutes. (Fig. 5)

[0126] Experimental Example

[0127] Figure 4 is an SEM image of a pattern in a Tin OH film after performing a lithography process using an ArF scanner.

[0128] Referring to Fig. 4, it can be seen that the thickness of the photoresist film in the exposed area, where the butyl group is removed as the photoreaction proceeds, decreases, while the thickness of the non-exposed area remains unchanged.

[0130] Figure 5 is an SEM image showing a Tin OH photoresist developed into a negative tone after dry development using Cl2 radical plasma.

[0131] Referring to Fig. 5, it can be seen that even after all the non-exposed Tin OH is removed, the exposed Tin OH remains in a line pattern.

[0132] In addition, it can be confirmed that a negative tone dry phenomenon is possible with Cl2 radical plasma.

[0134] Figure 6 is an example diagram showing the thickness of the exposed / unexposed TinOH film according to the dry development process time using Cl2 radical plasma.

[0135] Figure 6 shows the result of dry development by exposing a substrate with a patterned photoresist film formed thereon to a substrate temperature of 20 °C, a process pressure of 70 mTorr, an ICP source power of 400 W (13.56 MHz), and the injection of process gas Cl2 to form a radical plasma, and then exposing the substrate for 0 to 25 minutes.

[0136] Referring to Fig. 6, the thickness of the non-exposed TinOH layer can decrease rapidly as the exposure time to the radical plasma increases.

[0137] At this time, the thickness of the TinOH in the exposed area may be maintained or increased during a certain period of exposure to the radical plasma so that the film is not removed, and after a certain period, the thickness may decrease at a slower rate than that of the non-exposed area.

[0138] In other words, there may be a difference in the etching rate caused by Cl2 radicals in the non-exposed and exposed sections.

[0139] Finally, even after all the unexposed areas are removed, the exposed areas remain while maintaining the pattern, allowing the negative tone phenomenon of TinOH to proceed.

[0141] Figure 7 is a graph showing the XPS analysis results of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma.

[0142] Figure 7 shows that Figure 6 is a substrate temperature of 20 o This is the result of measuring the atomic % on the surface of a film that was dry developed by exposing a substrate with a patterned photoresist film formed by injecting a radical plasma with process gas Cl2, process pressure 70 mTorr, ICP source power 400 W (13.56 MHz), and process pressure 70 mTorr, ICP source power 400 W (13.56 MHz), and then exposing the film to the process gas for 0 to 25 minutes.

[0143] 1) 0 min; before exposure to Cl2 radical plasma

[0144] The unexposed portion has a Carbon : Oxygen : Sn % = 62 : 21 : 17% structure in which butyl groups are bonded to Sn, and the exposed portion has a Carbon : Oxygen : Sn % = 24 : 47 : 29% structure in which butyl groups bonded to Sn are detached, maintaining an oxygen-rich state.

[0145] 2) When exposed to Cl2 radical plasma for 1.5 minutes

[0146] In the non-exposed area, the rapid decrease in Carbon At.% and the rapid increase in Cl At.% due to Cl2 radicals may occur, while in the exposed area, unlike the non-exposed area, the Cl At.% may increase slightly.

[0147] 3) When exposed to Cl2 radical plasma for 1.5 minutes to 7 minutes

[0148] In the non-exposed area, Cl At.% gradually increases due to Cl2 radicals, whereas in the exposed area, unlike the non-exposed area, Cl At.% may increase slightly.

[0149] 4) When exposed to Cl2 radical plasma for 7 minutes to 20 minutes

[0150] In the non-exposed region, Cl At.% gradually increases while Sn At.% begins to decrease, and at the same time, Si At.% constituting the underlying film is detected after 12.5 minutes of processing, which is because the structure of the Tin OH photoresist film collapses as it thins.

[0151] In the exposed area, Cl At.% increases slightly, but Carbon / Oxygen / Sn At.% remains unchanged, unlike in the non-exposed area, a small amount of substrate peak is detected after 15 minutes of processing, but this is because the film thickness has decreased slightly.

[0152] 5) When exposed to Cl2 radical plasma for 25 minutes

[0153] In the non-exposed area, the residual film is completely removed, and only the At.% of the element associated with the underlying substrate peak is identified, while in the exposed area, the elements of the TinOH film from the photoreaction are retained, and only the thickness decreases slightly.

[0155] Figure 8 is a graph showing the measurement results of high-resolution O1s XPS spectra of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma.

[0156] Figure 8 shows the high resolution O1s XPS spectra of the unexposed / exposed TinOH surface before (0 min) and after exposure (1.5 min to 10 min) to the Cl2 radical plasma.

[0157] (a) Non-exposed area

[0158] Over time, a decrease in Sn-O, an increase in the Sn-OH / C=O peak, and an increase in the OH / CO peak can be observed.

[0159] At this time, it can be observed that the Sn-O bonds forming the core of the cage structure decrease rapidly as the exposure time increases. This may be attributed to the formation of volatile tin chloride through the reaction between Cl radicals and Sn within the film, which is then removed from the film.

[0160] Furthermore, in the case of the peak assigned to Sn-OH / C=O binding, the peak intensity increases over time; this can be interpreted as an increase in the C=O peak rather than the Sn-OH peak. (This is because the Sn at.% decreases as time passes. In other words, structural collapse and unremoved O combine with the surrounding carbon.)

[0161] At this time, the peak intensity of the OH / CO binding peak increases as the process time progresses, and this is also believed to be due to the cause described above.

[0162] In other words, it suggests that the chemical bonding state of the film, which was mainly composed of metal-oxide bonds, has changed to a bonding state composed of C=O.

[0163] (b) Exposure section

[0164] Even after exposure to radical plasma and the passage of process time, the chemical binding status can be maintained without significant change.

[0165] In this case, even when exposed to Cl2 radical plasma, unlike the non-exposed area, Sn is not removed and the structure can be maintained.

[0167] Figure 9 is a graph showing the measurement results of high-resolution C1s XPS spectra of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma.

[0168] Figure 9 shows the high resolution C1s XPS spectra of the unexposed / exposed TinOH surface before (0 min) and after exposure (1.5 min to 10 min) to the Cl2 radical plasma.

[0169] (a) Non-exposed area

[0170] Over time, a decrease in Sn-C, a decrease in CC, and an increase in the C-OH / Cl and C=O peaks can be observed.

[0171] At this time, since the butyl group is bonded to Sn, as the process time increases, the Sn-C bonds are removed, causing a decrease in Sn-C bonds, and the CC binding may also decrease due to the removed butyl group.

[0172] Due to the adsorption and chemical binding of Cl2 radicals, they easily react with carbon to form C-Cl bonds, and the bonding may increase as the process time increases.

[0173] The increase in C=O binding is believed to be due to the reasons shown in Figure 8 above.

[0174] (b) Exposure section

[0175] Over time, most of the C 1s peak may decrease, and only the C-Cl peak may increase slightly.

[0176] In other words, unlike the non-exposed TinOH, it can be seen that the degree of reaction between Cl radicals and the film is very small.

[0178] Figure 10 is a graph showing the measurement results of high resolution Cl 2p XPS spectra of exposed / unexposed TinOH films according to the dry development process time using Cl2 radical plasma.

[0179] Figure 10 shows the high-resolution Cl 2p XPS spectra measurement results of the unexposed / exposed TinOH surfaces before (0 min) and at different time intervals after exposure (1.5 min ~ 10 min) to the Cl2 radical plasma.

[0180] (a) Non-exposed area

[0181] After exposure to Cl radical plasma, chlorine that reacted with metal (Sn) and chlorine that reacted with C / O are simultaneously observed.

[0182] In the case of Cl reacting with Sn, it increases and then begins to decrease after a certain time. This is because, as described in Figure 7 above, Sn, which constitutes the cage structure, forms and removes volatile byproducts as the process time increases.

[0183] Due to the state of TinOH, where the cage structure begins to collapse due to the removal of Sn, the binding of organic chlorine (Cl reacted with C and O) becomes dominant over that of metallic chlorine.

[0184] (b) Exposure section

[0185] After exposure to Cl radical plasma, the chlorine peak reacting with metal (Sn) and the chlorine peak reacting with C / O, etc. can be simultaneously observed and may rise slightly.

[0186] In other words, there are fewer species that reacted with Cl than in the non-exposed TinOH, and as a result, there is a difference in the development rate (etching rate).

[0188] Finally, it can be confirmed that oxygen-rich exposed TinOH (exposed TinOH) with butyl groups attached does not chemically react well with chlorine compared to carbon-rich non-exposed TinOH with butyl groups.

[0189] That is, the above radical plasma can have a different etching rate, i.e., development rate, depending on the chemical binding state of the photoresist caused by the photolithography process, and negative tone dry development may be possible.

[0191] Figure 11 is a graph showing ln (development rate) at different temperatures of the substrate (second electrode) to calculate the activation energy of the exposed / unexposed TinOH during dry development using Cl2 radical plasma.

[0192] Referring to Fig. 11, k(T)

[0193] ( k(T) : development rate, A(T) : , R : Gas constant : 1.987 cal K -1 mol -1 , E a : activation energy, T : absolute temperature, A(T) : rate constant )

[0194] Non-exposed TinOH; E a = ~1.36 kcal / mol, exposure part TinOH; E a= ~4.19 kcal / mol, so the dry development rate of TinOH photoresist depends on the chemical reaction, and it can be confirmed that the dry development of TinOH in the exposure area with high activation energy is slow.

[0195] In other words, dry development is possible to selectively remove the exposed and unexposed areas.

[0197] Figure 12 shows a surface image of a TinOH photoresist pattern when the dry development process is performed with radical plasma and when the dry development process is performed by direct exposure to ICP plasma.

[0198] Referring to Fig. 11, it can be seen that the damage to the surface directly exposed to ICP plasma is more severe than the damage to the surface when the dry development process is performed with radical plasma.

[0199] This is damage caused by collisions of charged particles within the plasma.

[0201] Figure 13 is a surface image showing a TinOH photoresist line and space pattern after dry development using radical plasma (left) and a TinOH photoresist line and space pattern after wet development using developer (right).

[0202] Referring to Fig. 13, it can be seen that there is a lot of residue in the non-exposed portion removed after the wet development process.

[0203] On the other hand, after the dry development process using radical plasma, it can be confirmed that the non-exposed area is free of residue and particles.

[0204] Compared to wet processes, dry processes using radical plasma are easier to remove residues.

[0206] Figure 14 is a graph showing the dry development rate of the exposed Tin OH (black square) and the unexposed Tin OH (black empty square) at process pressures from 8 mtorr to 60 mtorr, and the dry development selectivity ratio [(unexposed dry development rate) / (exposed dry development rate)] (blue).

[0207] Referring to Fig. 14, it can be seen that as the process pressure increases, the dry development speed of the exposed and non-exposed sections decreases, but the dry development selectivity improves.

[0209] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0210] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0212] 100: Chamber 200: Light source 300: Plasma generator 301: First electrode 302: Gas inlet 400: Pattern forming section 401: Second electrode 402: Pump 500: Radical conversion unit 501: Radical conversion device

Claims

Claim 1 A step of depositing a photosensitive photoresist on a substrate, and then exposing the photoresist to a light source to form a coating layer on the substrate comprising an exposed portion and a non-exposed portion; a step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device equipped with a radical conversion device; a step of injecting a plasma generating gas into the dry developing device and applying power to a first electrode located at the top of the dry developing device to generate plasma; and a step of converting the plasma into radical plasma by a radical conversion device, and then A method for forming a dry pattern of a photoresist, comprising the step of selectively removing unexposed portions on a substrate by exposing a substrate having a coating layer formed on the second electrode to the radical plasma; wherein the radical conversion device comprises a first conductive substrate having a mesh-shaped or circular through-hole with a grid pattern and a second conductive substrate having a mesh-shaped or circular through-hole with a grid pattern, wherein the first conductive substrate is in a floating state electrically insulated from the chamber within the dry development device, and the second conductive substrate is in an electrically grounded state, wherein the through-holes of the first conductive substrate and the through-holes of the second conductive substrate are arranged to be staggered from each other, and wherein plasma generated from the upper part of the dry development device moves to a substrate on the second electrode located at the lower part, and passes through the through-holes of the radical conversion device to convert plasma ions into electrically neutral radical plasma. Claim 2 A method for forming a dry photoresist pattern according to claim 1, characterized in that, in the step of forming the coating layer, the photosensitive photoresist comprises a metal-organic cluster type photoresist, an organic hydrogen silses quioxane-based photoresist, an organic-inorganic hybrid photoresist, or a Keggin cluster type photoresist. Claim 3 delete Claim 4 A method for forming a dry photoresist pattern according to claim 1, wherein, in the step of installing the substrate having the coating layer formed thereon onto a second electrode located at the bottom of a dry developing device equipped with a radical conversion device, the diameter of the through hole of the radical conversion device is 50 μm to 500 μm. Claim 5 delete Claim 6 delete Claim 7 In claim 1, in the step of generating the plasma, the plasma generating gas is Cl2, BCl3, HBr, SiCl4, ClF3, HCl, CHF3, SF6, NF3, CF4, CF4, C x F y H z A method for forming a dry photoresist pattern characterized by using one or more reactive gases selected from the group consisting of O2, N2, and H2 (where x is a natural number from 1 to 6, y is a natural number from 4 to 8, and z is a natural number from 1 to 4), and one or more inert gases selected from the group consisting of Ar, Ne, He, and Xe. Claim 8 A photoresist dry pattern forming method according to claim 1, characterized in that, in the step of generating the plasma, the power intensity applied to the first electrode is 30 W to 5 kW. Claim 9 delete Claim 10 In claim 1, in the step of forming the pattern, the temperature of the second electrode applied to the device during the dry development process is -30 o C to 120 o A method for forming a dry photoresist pattern characterized by being C. Claim 11 A method for forming a dry photoresist pattern according to claim 1, characterized in that, in the step of forming the pattern, the pressure applied to the device during the dry development process is 3 mTorr to 300 mTorr. Claim 12 A chamber having an internal space for processing a substrate; a light source unit located on one side of the upper portion of the chamber and irradiating light onto a substrate coated with a photoresist pattern; a plasma generation unit located on the upper portion of the chamber and including a first electrode for generating plasma and a gas inlet for injecting plasma generating gas; a pattern forming unit located on the lower portion of the chamber and including a second electrode on which a substrate is installed and a pump for discharging residual gas; and a radical conversion unit located between the plasma generation unit and the pattern forming unit and including a radical conversion device for converting the plasma generated in the plasma generation unit into radical plasma; wherein the radical conversion device comprises a first conductive substrate having a mesh-shaped or circular through-hole with a grid pattern and a second conductive substrate having a mesh-shaped or circular through-hole with a grid pattern, wherein the first conductive substrate is in a floating state electrically insulated from the chamber within the dry developing device, and the second conductive substrate is in an electrically grounded state. A dry developing apparatus characterized in that the through holes of the first conductive substrate and the through holes of the second conductive substrate are arranged to be staggered from each other. Claim 13 delete Claim 14 A dry developing apparatus according to claim 12, characterized in that, in the radical conversion unit, the diameter of the through hole of the radical conversion device is 50 μm to 500 μm. Claim 15 delete Claim 16 delete

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