Resist underlayer deposition for improving photoresist performance

Abstract

The present disclosure relates generally to the field of semiconductor processing, and in particular to methods of forming resist underlayers for use in EUV lithography processes. In some embodiments, the present disclosure provides a method for forming a resist underlayer with improved adhesion using a resist underlayer agent. In some embodiments, the resist underlayer is formed using the resist underlayer agent in a UV-assisted deposition process.

Description

background Technical Field

[0001] The embodiments of this disclosure generally relate to the field of semiconductor processing, and more specifically to a method for forming a resist underlayer for use in EUV flatbed printing processes. Background Technology

[0002] As the geometry of electronic components shrinks, the lithography and patterning of electronic component designs become increasingly challenging. A single lithography exposure may not provide sufficient resolution. Typically, to fabricate integrated circuits (ICs), multiple patterning techniques and additional metal layers are used to increase feature density. The implementation of multiple patterning techniques and additional metal layers complicates the manufacturing process and makes it expensive.

[0003] The demand for higher integrated circuit density also places demands on the process sequences used in the manufacture of integrated circuit components. For example, the process sequence for manufacturing semiconductor devices using conventional lithography technology mainly employs four operations. These operations include (1) photoresist or "resist" coating; (2) exposure; (3) wet development; and (4) etching. Photoresist coating may include an energy-sensitive resist layer formed on a stack of material layers deposited on a substrate. This energy-sensitive resist layer is exposed to a patterned image to form a photoresist mask. Subsequently, an etching process is used to transfer the mask pattern onto one or more of the stacked material layers. The chemical etchant used in the etching process is selected to have a higher etch selectivity for the stacked material layers than for the energy-sensitive resist mask. That is, the chemical etchant etches one or more layers of the material stack at a much faster rate than it etches the energy-sensitive resist. The etch selectivity of the stacked material layers above the photoresist prevents the energy-sensitive photoresist from being consumed before the pattern transfer is complete.

[0004] Extreme ultraviolet (EUV) lithography typically uses EUV wavelengths much shorter than those of conventional techniques to proportionally reduce feature sizes on IC chips. EUV lithography typically uses EUV resists patterned with an EUV wavelength of approximately 13.5 nm. However, EUV resists have significantly lower etch resistance than photoresists used in conventional patterning techniques. Currently, the integrity of EUV resist patterns produced by etching is very poor compared to conventional photoresists. To form features on a substrate using EUV lithography, a resist underlayer is typically deposited on the substrate, followed by an EUV photoresist layer. As the feature size of the device decreases, the resist underlayer can ideally be thinner to allow for the formation of etched features with the desired resolution or aspect ratio.

[0005] Several important properties exist in offset printing. These include sensitivity, resolution, low line-edge roughness (LER), etch resistance, and the ability to form thinner layers. Higher sensitivity requires less energy to alter the solubility of the deposited film, resulting in higher efficiency in offset printing. Resolution and LER determine how narrow features can be achieved through offset printing. Pattern transfer requires materials with higher etch resistance to form deep structures. Higher etch resistance also enables thinner films. Thinner films increase the efficiency of offset printing.

[0006] The aforementioned photolithography process may have several drawbacks. For example, wet development of the resist, due to the acid gradient at the mask edges, can produce patterns with resist line edge roughness (LER). This can lead to uncertainty in predicting the line edges produced after wet development. High aspect ratio patterns are increasingly being used to improve resist roughness performance and provide stronger etch resistance, allowing for a wider etch transfer margin. However, high aspect ratio patterns can also increase the tendency for pattern collapse. As device dimensions shrink, capillary forces due to smaller feature sizes can cause pattern collapse during wet development and cleaning processes. Addressing photoresist pattern collapse is crucial to enabling further miniaturization of EUV photolithography resist pattern transfer. While capillary forces may be the primary cause of pattern collapse, other factors that can affect it include the adhesion between the photoresist and the substrate.

[0007] The need for ever-reducing feature sizes has led to the use of thinner films to prevent pattern collapse. Therefore, the thickness of the energy-sensitive EUV photoresist can be correspondingly reduced to control pattern resolution. However, when using thin photoresist, a single EUV photoresist may not be able to capture sufficient EUV exposure dose. Therefore, a resist underlayer is typically used between the energy-sensitive EUV photoresist and the underlying substrate material layer to help facilitate pattern transfer. The resist underlayer can also aid pattern transfer by smoothing the surface roughness of the substrate, thereby improving exposure results. The resist underlayer can also help improve EUV exposure results by normalizing surface energy and increasing photoresist adhesion; both of these contribute to reducing the risk of pattern collapse. However, while a dense underlayer can improve selectivity by providing strong contrast with the EUV photoresist, a dense underlayer also etches more slowly, increasing the resist's exposure to etching chemicals. If the EUV photoresist is too thin, it may be etched away before the etching process is complete. Therefore, as the thickness of the EUV photoresist decreases, the thickness of the underlying layer should also decrease.

[0008] Therefore, there is a need in the art for improved thin resist substrates that have improved photoresist adhesion to reduce pattern collapse, and for methods used to form such thin resist substrates. Summary of the Invention

[0009] The embodiments described herein generally relate to methods for forming a resist underlayer with increased photoresist adhesion on a substrate for use in an EUV flatbed printing process. In one embodiment, a method for forming a resist underlayer on a substrate is provided. The method includes: exposing the substrate to a resist underlayer to deposit a resist underlayer over a top surface of the substrate, wherein the resist underlayer comprises having a general structure The compound in which R 1 R 2 and R 3 For each having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17, and A 1 It can be a hydrogen atom, chlorine atom, bromine atom, iodine atom, or amine group.

[0010] In another embodiment, a method for forming a resist underlayer on a substrate is provided. The method includes: exposing the substrate to UV radiation in a resist underlayer atmosphere to deposit a resist underlayer over a top surface of the substrate, wherein the resist underlayer comprises a resist having a general structure. The compound. In some embodiments of the resist underlayer, R 1 R 2 and R 3 For each having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17, and A 1 It is hydrogen or contains at least one of the following: C x H y The amine group of the hydrocarbon functional group, wherein x ranges between 1 and 8 and y ranges between 1 and 17.

[0011] In another embodiment, a method is provided for forming a resist underlayer on a substrate within a processing chamber. The method includes: positioning the substrate in a processing region of the processing chamber, and allowing a resist underlayer to flow into the processing region, wherein the resist underlayer comprises materials having a universal structure. The compound in which R 1 R 2 and R 3 For each having the general formula C x H yThe hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17, and A 1 The group is a hydrogen or amine group. The method also includes exposing the substrate to a resist underlayer to deposit the resist underlayer on the top surface of the substrate. Attached Figure Description

[0012] To gain a more detailed understanding of the features described above, a more specific description of the present disclosure can be provided with reference to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be construed as limiting their scope, and other equally effective embodiments are permissible.

[0013] Figure 1 This is a partial cross-sectional view of a processing chamber according to certain embodiments of this disclosure; Figure 2 This is based on certain embodiments of the present disclosure. Figure 1 A schematic isometric cross-sectional view of a portion of the processing chamber; Figure 3 This is based on certain embodiments of the present disclosure. Figure 2 A schematic cross-sectional view of the processing chamber shows the gas flow path; Figure 4 It is a process flow diagram depicting a method for forming a resist underlayer in a deposition process using a resist underlayer agent according to certain embodiments described herein; Figure 5 This is a process flow diagram depicting a method for forming a resist underlayer using a resist underlayer in an ultraviolet (UV) assisted deposition process according to certain embodiments described herein; Figure 6 It is a table depicting the changes in the carbon composition of the substrate caused by the resist underlayer formed according to certain embodiments described herein; Figure 7 This is a table depicting the changes in surface energy of the substrate caused by the resist underlayer formed according to certain embodiments described herein; and Figure 8 This is a table depicting the changes in adhesive work between the photoresist and the substrate due to the resist underlayer formed according to certain embodiments described herein.

[0014] To facilitate understanding, the same reference numerals are used to denote common elements in the figures where possible. Elements and features of one embodiment are contemplated to be advantageously incorporated into other embodiments without further description. Detailed Implementation

[0015] This document describes a method for forming a resist underlayer on a substrate for use in an EUV flatbed printing process. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that embodiments of this disclosure can be practiced without such specific details. In other instances, well-known aspects, such as integrated circuit manufacturing, have not been described in detail so as not to unnecessarily obscure embodiments of this disclosure. Furthermore, it should be understood that the various embodiments shown in the accompanying drawings are illustrative representations and are not necessarily drawn to scale.

[0016] As used herein, “substrate” means any substrate or material surface formed on a substrate during a manufacturing process. For example, depending on the application, substrate surfaces on which processing can be performed include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. Substrates can be exposed to pretreatment processes such as polishing, etching, reduction, oxidation, hydroxylation, annealing, UV curing, electron beam curing, and / or baking of the substrate surface. In addition to processing directly on the surface of the substrate itself, any of the processing steps disclosed in this disclosure can also be performed on an intermediate layer formed on the substrate, as disclosed in more detail below, and the term “substrate surface” is intended to include such intermediate layers as indicated by the context. Thus, for example, where a film / layer or a portion of a film / layer has already been deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0017] To provide context, as feature and component sizes decrease, the stack thickness also decreases. Therefore, the resist underlayer can be preferably thinner to allow for the formation of etched features with the desired resolution and / or aspect ratio. As the resist film thickness decreases, adhesion at the interface between the resist underlayer and the EUV photoresist may decrease due to the surface energy mismatch between the two materials. Poor adhesion between the resist underlayer and the EUV photoresist can lead to poor line width roughness (LWR), line pattern collapse (LPC), and / or other lithography-related defects.

[0018] This disclosure provides a method for forming a resist underlayer using a UV-assisted deposition process to create a resist underlayer with improved adhesion between the resist underlayer and an EUV photoresist disposed thereon. In the UV-assisted deposition process, a gaseous or vaporized resist underlayer agent is introduced into a processing chamber along with a carrier gas (such as He or Ar). The resist underlayer agent can then be activated using UV light to form an ultrathin monomolecular underlayer over a substrate. In various embodiments, the resist underlayer agent may contain compounds that bond to OH molecules on the substrate surface (e.g., the SiOx surface of a silicon substrate), thereby reducing the polar groups on the SiOx surface. Treatment with the resist underlayer agent can also correspondingly increase the number of surface hydrocarbon functional groups on the substrate surface, thereby enabling higher substrate coverage and altering its surface energy to increase the adhesion work to the EUV photoresist. Various embodiments of this disclosure are discussed in more detail below.

[0019] Figure 1 A cross-sectional view of an exemplary tandem processing chamber 100, which can be used to perform the methods disclosed herein according to certain embodiments, is illustrated. The processing chamber 100 provides two separate and adjacent processing regions within a chamber body for processing substrates. The processing chamber 100 has a cover 102, a housing 104, and a power supply 106. Each housing in the housing 104 covers a corresponding one of two UV lamps 122, which are respectively disposed above two processing regions 160 defined within a body 162. Each processing region 160 includes a heated substrate support, such as a substrate support 124, for supporting a substrate 126 within the processing region 160. The UV lamps 122 emit UV light, which is directed through a window 108 and a spray head 110 to each substrate located within each processing region. The substrate support 124 may be made of ceramic or metal, such as aluminum. A substrate support 124 may be coupled to a rod 128 that extends through the bottom of the body 162 and is operated by a drive system 130 to move the substrate support 124 in the processing area 160 toward and away from the UV lamp 122. The drive system 130 may also rotate and / or translate the substrate support 124 during curing to further enhance the uniformity of substrate illumination. An exemplary tandem processing chamber 100 may be incorporated into a processing system, such as the Producer™ processing system available from Applied Materials, Inc., of Santa Clara, California.

[0020] UV bulb 122 can be a light-emitting diode or bulb array utilizing any state-of-the-art UV illumination source, including but not limited to microwave arcs, radio frequency filaments (capacitively coupled plasma), and inductively coupled plasma (ICP) lamps. Various concepts for enhancing the uniformity of substrate illumination include the use of lamp arrays, which can also be used to alter the wavelength distribution of incident light; relative movement between the substrate and the lamp head, including rotation and periodic translation (sweeping); and real-time modification of the shape and / or position of the lamp reflector. The UV bulb is an ultraviolet radiation source and can transmit UV and infrared (IR) radiation across a wide spectral range.

[0021] UV lamp 122 emits light across a broad wavelength band from 170 nm to 400 nm. The wavelength emitted is determined by the gas selected for use within UV lamp 122. UV light emitted from UV lamp 122 enters processing zone 160 through a window 108 located within an aperture in cover 102 and a gas distribution spray head 110. Window 108 may be made of OH-free synthetic quartz glass and has sufficient thickness to maintain a vacuum without breaking. Window 108 may be fused silica, which transmits UV light down to approximately 150 nm. Spray head 110 may be made of a transparent material such as quartz or sapphire and is located between window 108 and substrate support 124. Because cover 102 is sealed to body 162 and window 108 is sealed to cover 102, the volume provided by processing zone 160 is capable of maintaining a pressure of approximately 0.5 Torr to approximately 650 Torr. Processing gas or cleaning gas may enter processing zone 160 through one of the two inlet channels 132. Then, the treatment gas or cleaning gas leaves the treatment area 160 through the common outlet port 134.

[0022] Each housing in housing 104 includes an aperture 115 adjacent to the power source 106. Housing 104 may include an internal parabolic surface defined by a cast quartz liner 136 coated with a dichroic film. The dichroic film typically comprises a periodic multilayer film of various dielectric materials having alternating high and low refractive indices. Thus, the quartz liner 136 can transmit infrared light and reflect UV light emitted from the UV lamp 122. By moving and changing the shape of the internal parabolic surface, the quartz liner 136 can be adjusted to better suit each process or task.

[0023] Figure 2 The illustration shows a schematic isometric cross-sectional view of a portion of a processing chamber 200, which can be used alone or in place of any processing area of ​​a series processing chamber 100. Figure 2The hardware design shown enables a specific gas flow profile distribution to be achieved on substrate 126 being processed in a UV chamber, lamp-heated chamber, or other chamber that uses light energy to process membranes or catalytic reactions, whether directly on or above substrate 126.

[0024] A window assembly is located within the processing chamber 200 to hold a first window, such as a UV vacuum window 212. This window assembly includes a vacuum window clamp 210, which can be placed directly or indirectly on a portion of the body 162. Figure 1 A vacuum window 212 is provided, through which UV light can be transmitted from the UV lamp 122. The vacuum window 212 is typically located between the UV radiation source (such as the UV lamp 122) and the substrate support 124. A spray head 214, which may be formed of various transparent materials (such as quartz or sapphire), is located within the processing area 160 and between the vacuum window 212 and the substrate support 124. The transparent spray head 214 forms a second window through which UV light can be transmitted to the substrate 126. The transparent spray head defines an upper processing area 220 between the vacuum window 212 and the transparent spray head 214, and further defines a lower processing area 222 between the transparent spray head 214 and the substrate support (such as the substrate support 124). The transparent spray head 214 also has one or more channels 216 between the upper processing area 220 and the lower processing area 222. Channel 216 may have a roughened inner surface to scatter UV light, so that no light pattern appears on substrate 126 during processing. The size and density of channel 216 may be uniform or non-uniform to achieve the desired flow characteristics across the entire substrate surface. Channel 216 may have a uniform flow profile, wherein the flow rate per radial area on substrate 126 is uniform, or the gas flow may preferentially flow to the center or edge of substrate 126, i.e., the gas flow may have a preferential flow profile.

[0025] The front and / or rear surfaces of the transparent spray head 214 and vacuum window 212 can be coated to have a bandpass filter and improve the transmission of the desired wavelength or improve the irradiance profile of the substrate. For example, an anti-reflective coating (ARC) layer can be deposited on the transparent spray head 214 and vacuum window 212 to improve the transmission efficiency of the desired wavelength. The ARC layer can be deposited such that the thickness of the reflective coating at the radial edge is relatively thicker than that at the center of the transparent spray head 214 and vacuum window 212, so that the periphery of the substrate disposed below the vacuum window 212 and transparent spray head 214 receives higher UV irradiance than the center. The ARC coating can be a composite layer having one or more layers formed on the surfaces of the vacuum window 212 and transparent spray head 214. The composition and thickness of the reflective coating can be customized based on the incident angle, wavelength, and / or irradiance intensity of the UV radiation.

[0026] A gas distribution ring 224, made of alumina, is located within the processing region 160, near the sidewall of the UV chamber. The gas distribution ring 224 may be a single piece (not shown) or may include a gas inlet ring 223 and a base distribution ring 221 having one or more gas distribution ring channels 226. The gas distribution ring 224 is configured to generally surround the circumference of the vacuum window 212. The gas inlet ring 223 may be coupled to the base distribution ring 221, and together they may define a channel 228 within the gas distribution ring. Gas supply source 242 ( Figure 3 The gas is coupled to one or more gas inlets (not shown) formed in the surface of the gas inlet ring 223, through which gas enters the gas distribution ring inner channel 228. One or more gas distribution ring channels 226 couple the gas distribution ring inner channel 228 to the upper processing area 220, thereby forming a gas flow path between the inner channel 228 and the upper processing area 220 above the transparent spray head 214.

[0027] The gas outlet ring 230 is located below the gas distribution ring 224 and may be at least partially below the transparent spray head 214 within the processing area 160. The gas outlet ring 230 is configured to surround the circumference of the transparent spray head 214 and has one or more gas outlet channels 236 that couple the inner channel 234 of the gas outlet ring to the lower processing area 222, thereby forming a gas flow path between the lower processing area 222 and the inner channel 234 of the gas outlet ring. The one or more gas outlet channels 236 of the gas outlet ring 230 are at least partially located below the transparent spray head 214.

[0028] Figure 3 Depicting Figure 2A schematic cross-sectional view of the processing chamber 200 shows the gas flow path. As indicated by arrow 302, a processing gas (such as a resist underlayer and / or other types of gas, discussed below) can be injected and uniformly filled in the upper processing region 220 between the vacuum window 212 and the transparent spray head 214, passing through the transparent spray head 214, reaching above the substrate support 124 on which the substrate 126 may be disposed, and downwards from the transparent spray head 214 toward the substrate. The airflow washes over the substrate 126 from above, diffuses concentrically, and exits the lower processing region 222 through the gas outlet channel 236. The gas is then ejected from the lower processing region 222, enters the gas outlet ring channel 234, exits the gas outlet 238 into the exhaust port 240, and reaches the pump 310. Depending on the pattern of the channel 216 in the spray head 214, the gas flow profile on the substrate 126 can be controlled to provide the desired uniform or non-uniform distribution.

[0029] To improve dissociation efficiency, additional heaters (such as...) can be used. Figure 2 The heaters 248 and 250 shown are used to heat other components in the processing chamber, such as the vacuum window clamp 210, the gas distribution ring 224, and the substrate support 124.

[0030] Figure 4 An exemplary method 400 for forming a resist underlayer on a substrate is illustrated. It should be noted that... Figure 4 The sequence of steps shown is not intended to limit the scope of this disclosure, as one or more steps may be added, deleted, and / or reordered without departing from the basic scope of this disclosure.

[0031] Method 400 begins with operation 401, in which a substrate is positioned in the processing area of ​​a processing chamber. In some embodiments, the distance between the substrate and the spray head of the processing chamber can range from about 400 mm to about 1400 mm. In some embodiments, the processing chamber can be a deposition chamber configured to deposit material onto the substrate using a vapor deposition process (thermal or plasma-enhanced), such as atomic layer deposition (ALD), plasma-enhanced ALD (PEALD), chemical vapor deposition (CVD), or plasma-enhanced chemical vapor deposition (PECVD). In some embodiments, the processing chamber can be a UV-based processing chamber for forming a resist underlayer on the substrate using a UV-assisted deposition process, as described below in method 500.

[0032] In some embodiments, after the substrate is placed in the processing area of ​​the processing chamber, method 400 may continue to operation 402, such that a resist underlayer can be formed directly on the top surface of the substrate. In other embodiments, operation 402 may be performed after one or more interlayers are formed on the substrate, such that one or more additional interlayers can be provided between the resist underlayer and the substrate.

[0033] Next, in operation 402, the resist underlayer is flowed into the processing area of ​​the processing chamber. In one embodiment, the resist underlayer may be flowed into the processing area along with a carrier gas (such as He or Ar) that is inert to the process occurring in the processing chamber. The flow rate of the resist underlayer may be from about 100 milligrams per minute (mgm) to about 2000 mgm, for example, about 1000 mgm. The flow rate of the carrier gas may be from about 500 standard cubic centimeters per minute (sccm) to about 5000 sccm, for example, about 2000 sccm. The resist underlayer may also be delivered with or without heating. It should be understood that the process conditions described herein are based on a substrate with a diameter of 300 mm.

[0034] In some embodiments, the resist underlayer comprises a compound represented by formula (I):

[0035] Where R1 R 2 and R 3 For having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17. In some embodiments, R 1 R 2 and R 3 It can consist entirely of the same functional groups or entirely of different functional groups. In some implementations, R 1 R 2 and R 3 Only some of them can be the same functional groups. In some implementations, R 1 R 2 and / or R 3 It may include alkyl, olefin, or alkyne groups having 1 to 8 carbon atoms and having a straight-chain, branched, or cyclic structure. In some embodiments, it is used for R 1 R 2 and R 3 Each of the suitable hydrocarbon compounds can independently contain straight-chain or branched C atoms. 1-8 Alkyl, C 1-8 Alkenes or C 1-8 Alkyne group.

[0036] In some implementations, for R 1 R 2 and R 3 Each of the suitable hydrocarbon compounds may independently contain, but is not limited to, a methyl group (CH3), an ethyl group (C2H5), a propyl group (C3H7), a butyl group (C4H9), an isobutyl group ((CH3)2CH CH2), a tert-butyl group ((CH3)3C), or an isopropyl group ((CH3)2CH).

[0037] In some embodiments, the resist underlayer according to formula (I) may be a silane, wherein A 1 It is a hydrogen atom. In other embodiments, the resist underlayer can be silicone, wherein A 1 It is an amine group.

[0038] In some implementations, A 1 It can be a primary amine group represented by formula (II):

[0039] Where R 4 For having the general formula C x H yThe hydrocarbon functional group, where x ranges from 1 to 8 and y ranges from 1 to 17, as described above for R. 1 R 2 and R 3 As stated above.

[0040] In other embodiments, A 1 It can be a secondary amine group represented by formula (III);

[0041] Where R 4 and R 5 For having the general formula C x H y The hydrocarbon functional group, where x ranges from 1 to 8 and y ranges from 1 to 17, as described above for R. 1 R 2 and R 3 As stated. When A 1 When R is a secondary amine group, 4 and R 5 They can be the same hydrocarbon functional group or different hydrocarbon functional groups.

[0042] In another implementation, A 1 Other functional groups can be used to modify the material to achieve optimal interaction with the corresponding functional groups in the EUV photoresist to be deposited on it. For example, A 1 It can contain Cl, Br, I or .

[0043] In one embodiment, the exemplary resist underlayer is represented by the following compound (IV):

[0044] Next, in operation 403, the substrate in the processing area is exposed to a resist underlayer, which may be in the form of a gas or vaporized liquid vapor. During operation 403, the processing chamber may be heated to a temperature of approximately 40°C to approximately 500°C, for example, approximately 200°C to approximately 400°C, such as approximately 385°C. The chamber pressure may be approximately 0.1 Torr to approximately 50 Torr, for example, approximately 0.5 Torr to approximately 20 Torr.

[0045] Operation 403 can be performed for approximately 15 seconds to approximately 900 seconds, such as approximately 60 seconds, to form a resist underlayer (or, if present, one or more interlayers disposed thereon) on the top surface of the substrate. In some embodiments, the processing time can be extended to improve coverage. In some embodiments, the thickness of the resist underlayer can be less than approximately 50 nanometers, such as less than approximately 20 nanometers, such as less than approximately 10 nanometers, such as less than approximately 5 nanometers, such as less than or approximately 3 nanometers.

[0046] Figure 5 The illustration depicts an exemplary method 500 of forming a resist underlayer on a substrate using a UV-assisted deposition process according to certain embodiments of the present disclosure. The UV-assisted deposition process can utilize any UV-based processing chamber, such as… Figure 1 and Figure 2 The UV treatment chambers 100 and 200 shown are used for this process. It should be noted that... Figure 5 The sequence of steps shown is not intended to limit the scope of this disclosure, as one or more steps may be added, deleted, and / or reordered without departing from the basic scope of this disclosure.

[0047] Method 500 begins with operation 501, and the operation follows the steps outlined above. Figure 3 The method described places the substrate in the processing area of ​​the UV-based processing chamber.

[0048] In some embodiments, method 500 may continue to operation 502 immediately after the substrate is placed in the processing chamber in operation 501, such that the resist underlayer can be formed directly on the top surface of the substrate. In other embodiments, operation 502 may be performed after depositing one or more interlayers on the substrate prior to forming the resist underlayer, such that one or more additional interlayers can be provided between the resist underlayer and the substrate.

[0049] In operation 502, the resist underlayer as described above with respect to method 400 is introduced into the UV-based processing chamber. In one embodiment, the resist underlayer may be introduced into the processing area of ​​the processing chamber along with a carrier gas (such as He or Ar) that is inert to the process occurring in the processing chamber.

[0050] The flow rate of the resist underlayer can be from about 100 mg / min to about 2000 mg / min, for example, about 1000 mg / min. The flow rate of the carrier gas can be from about 500 standard cubic centimeters / min to about 5000 sccm, for example, about 2000 sccm. In operation 502, the resist underlayer can be delivered with or without heating.

[0051] As discussed above, in operation 503, the processing area in the UV-based processing chamber can be positioned such that UV radiation can be delivered through window 108 to promote the photolysis of the resist underlayer. In operation 503, when the resist underlayer is delivered from the UV transparent window to the UV transparent gas distribution spray head (e.g., as described above regarding...), Figure 2 and Figure 3The area between the vacuum window 212 and the transparent spray head 214 (discussed) provides UV radiation when the UV transparent gas distribution spray head flows toward the substrate.

[0052] By turning on the UV unit (such as Figure 1 and Figure 2 The UV lamp 122 shown performs operation 503 to assist in the dissociation of chemical bonds in the precursor of the resist underlay. The UV units can be switched on simultaneously with or after the resist underlay flows into the UV-based processing chamber. In some embodiments, the uniformity of UV radiation exposure can be tuned using the spacing and rotation of the UV units within the UV-based processing chamber. In some embodiments, the power of the UV units and the UV lamp 122 is approximately 12 kW. In some embodiments, the UV power output of the UV lamp 122 for operation 503 can be from approximately 1% to approximately 100%, such as between approximately 50% and approximately 90%, such as approximately 80%.

[0053] In operation 504, the substrate in the processing area is exposed to a resist underlayer, which may be in the form of a gas or vaporized liquid vapor. During operation 504, the processing chamber may be heated to a temperature of approximately 40°C to approximately 500°C, for example, approximately 200°C to approximately 400°C, such as approximately 385°C. The chamber pressure may be approximately 0.1 Torr to approximately 50 Torr, for example, approximately 0.5 Torr to approximately 20 Torr.

[0054] Operation 504 can be performed for approximately 15 seconds to approximately 900 seconds, such as approximately 60 seconds, to form a resist underlayer (or, if present, one or more interlayers disposed thereon) on the top surface of the substrate. In some embodiments, the processing time can be extended to improve coverage. In some embodiments, the thickness of the resist underlayer can be less than approximately 50 nanometers, such as less than approximately 20 nanometers, such as less than approximately 10 nanometers, such as less than approximately 5 nanometers, such as less than or approximately 3 nanometers.

[0055] The following non-limiting examples are provided to further illustrate the implementation methods described herein. However, these examples are not intended to encompass all aspects and are not intended to limit the scope of the implementation methods described herein.

[0056] In some embodiments, the advantages of this disclosure provide improved resist underlayer coverage and adhesion to the EUV photoresist deposited thereon. In one embodiment, as discussed above, the resist underlayer typically provides improved adhesion to the EUV photoresist by increasing coverage and correspondingly reducing the polarity of the substrate surface interacting with the photoresist. For example, as applied when forming a resist underlayer on a SiO2 substrate, the hydrocarbon precursor of the resist underlayer reacts with and bonds to polar OH molecules as the resist underlayer is deposited, thereby reducing the polarity of the substrate surface. Therefore, the bonding of the hydrocarbon precursor to the polar OH molecules of the SiO2 substrate can also be considered to represent the resist underlayer coverage, which is determined by measuring the corresponding change in the carbon atom composition on the substrate surface after the formation of the resist underlayer.

[0057] A resist underlayer was formed on the surface of a SiO2 substrate using methods 400 and 500 described above. The surface composition of carbon atoms on the top surface of each resist underlayer was measured by surface XPS analysis to determine the coverage of each resist underlayer, as indicated by the percentage of hydrocarbon functional groups bonded to the substrate. Results are as follows: Figure 6 As shown in Figure 600, the carbon atom percentage composition measurements of the substrate surfaces of plasma-treated SiO2 substrates, SiO2 substrates having a resist underlayer formed from a precursor containing HMDS, and SiO2 substrates having a resist underlayer formed using a resist underlayer agent (with and without UV exposure) are depicted.

[0058] As expected, the percentage of carbon content on the substrate surface increases dramatically when a resist underlayer is formed on the substrate surface. The measured carbon content of each resist underlayer (e.g., formed using HMDS and a resist underlay agent) is greater than that of the plasma-treated substrate. However, when comparing resist underlayers formed by conventional means (e.g., flow of HMDS precursor) with the resist underlay agent, resist underlayers formed using the resist underlay agent (with and without UV exposure) exhibit even higher percentages of carbon atoms, indicating higher coverage of the substrate with the resist underlayer formed using a precursor containing the resist underlay agent. Regarding resist underlayers formed using the resist underlay agent, it has also been observed that exposing the substrate to UV radiation during resist underlayer deposition, as described in operation 401 above, generates even higher percentages of carbon-containing functional groups on the substrate surface. Therefore, exposure to UV radiation during the deposition process using the resist underlay agent helps to further increase the resist underlayer coverage on the surface.

[0059] In some embodiments, the method of this disclosure also provides forming a resist underlayer with surface energy modified by a reduced polarity content, in order to increase adhesion at the interface between the resist underlayer and the EUV photoresist deposited thereon. For example, as Figure 7 As shown, Table 700 displays surface energy data derived from contact angle measurements. Figure 6 The polarity content of each surface in the corresponding surface analyzed. Specifically, Figure 7 The illustration shows a comparison of the corresponding polar surface energy portions of the substrate surfaces of a plasma-treated SiO2 substrate, a SiO2 substrate with a resist underlayer formed using HMDS, and a SiO2 substrate with a resist underlayer formed using a resist underlayer agent (with and without UV exposure).

[0060] Furthermore, as expected, when a resist underlayer is formed on the surface of the substrate, the polarity content on the analyzed substrate surface is significantly reduced. Comparing a resist underlayer formed using HMDS with one formed using a resist underlay agent, the reduction in the polarity content of the surface energy on the substrate surface is greater when the resist underlayer is formed using the resist underlay agent. This greater reduction in polarity content indicates that the method and resist underlay agent of this disclosure are more efficient in eliminating polar groups on the substrate surface. Between resist underlayers formed with and without UV exposure using the resist underlay agent, the reduction in surface energy polarity is greater when a resist underlayer is formed with UV radiation exposure (as in method 500) compared to when a resist underlayer is deposited without UV radiation exposure (as in method 400).

[0061] The greater coverage and reduced surface energy polarity achieved by a resist underlayer formed with a resist underlayer allow for increased photoresist adhesion. As discussed above, increased adhesion between the photoresist and the substrate surface can reduce the risk of pattern collapse. In some embodiments, resist underlayers formed using a resist underlayer that exhibit greater coverage and a greater reduction in surface energy polarity on the substrate exhibit greater adhesive work, such as... Figure 8 As shown.

[0062] Adhesive work is an effective evaluation factor for substrate-photoresist interactions because it takes into account the surface energy of the resist substrate (R), liquid developer (L), and substrate (S). Adhesive work, calculated based on surface free energy, can be defined as the work required to pull EUV photoresist off the substrate in the developer solution. Therefore, a higher adhesive work indicates an improvement in the adhesion between the EUV photoresist and the substrate. The adhesive work W can be estimated using the following equation:

[0063] in, γ RL It is the interfacial force between the photoresist and the liquid developer. γ SL It is the interfacial force between the resist layer on the substrate and the liquid developer. γ RS It is the interfacial force between the photoresist and the resist layer on the substrate, and the surface free energy of the substrate. γ SL It was calculated using contact angle measurements in two known surface free energy solvents.

[0064] Figure 8 Table 800 is shown, depicting the adhesive work required to remove EUV photoresist disposed on a substrate. In the example shown, the adhesive work is compared when the EUV photoresist is directly disposed on a SiO2 substrate without a resist underlayer, and when resist underlayers formed using HMDS and resist underlayers (with and without UV radiation assistance) are each disposed between the photoresist and the substrate. In this example, the adhesive work is measured when the photoresist and the corresponding resist underlayer and / or substrate are immersed in a developer (e.g., a 2.38% tetramethylammonium hydroxide (TMAH) solution used as the developer). As shown, the adhesive work increases when a resist underlayer (formed using HMDS or a resist underlayer) is disposed between the photoresist and the substrate. The adhesive work is significantly increased between resist underlayers formed using HMDS and resist underlayers, particularly with and without UV radiation assistance. Figure 6 and Figure 7 The results show that the adhesion work of the resist underlay deposited with a resist underlay in the presence of UV radiation exposure (as in method 500) is further increased compared with the adhesion of the resist underlay deposited with a resist underlay without UV radiation exposure (as in method 400).

[0065] Embodiments of this disclosure use a resist underlayer to deposit a resist underlayer on a substrate. The resist underlayer formed on the substrate exhibits increased coverage, reduced surface energy polarity, and increased adhesive work. Therefore, the adhesion between the resist underlayer and the EUV photoresist deposited thereon is improved. Specifically, the resist underlayer used to form the resist underlayer contains a compound consisting of silicon atoms bonded to three hydrocarbon functional groups and one amine group. Furthermore, the benefits provided by the resist underlayer deposited using the resist underlayer are further enhanced when the resist underlayer is deposited using a UV-assisted deposition process in a UV-based processing chamber. Using a UV-assisted deposition process to form the deposited resist underlayer allows for the formation of monomolecular resist underlayers with tunable surface energies for different resist underlayer precursors. The resist underlayer precursor can be customized based on the EUV photoresist intended to be used with the resist underlayer to increase the adhesion of the EUV photoresist to the resist underlayer. Therefore, this disclosure provides improved adhesion between the resist substrate and the EUV photoresist, thereby improving line width roughness (LWR) and minimizing line pattern collapse (LPC) of the patterned EUV photoresist. This disclosure also provides a way to reduce the risk of LPC without reducing the thickness of the EUV photoresist, enabling the maintenance and / or improvement of the etch resistance of the EUV photoresist.

[0066] Although the foregoing describes an implementation of this disclosure, other and further implementations of this disclosure may be designed without departing from the basic scope of this disclosure.

Claims

1. A method for forming a resist underlayer on a substrate, the method comprising: The substrate is exposed to a resist underlayer to form the resist underlayer above the top surface of the substrate, the resist underlayer comprising a compound having a structure represented by Formula I: Where R 1 R 2 and R 3 For each having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8, y ranges from 1 to 17, and A 1 It can be a hydrogen atom, chlorine atom, bromine atom, iodine atom, or amine group.

2. The method of claim 1, wherein R 1 R 2 , and R 3 All or some of them are the same hydrocarbon functional groups.

3. The method of claim 1, further comprising: The substrate and the resist underlayer are exposed to UV radiation to photodegrade the resist underlayer.

4. The method of claim 1, wherein A 1 It contains at least one with the general formula C x H y The amine group of the hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17.

5. The method of claim 1, wherein A 1 It is a primary amine group, wherein the primary amine group comprises a nitrogen atom, a hydrogen atom, and a carbon atom having the general formula C bonded to a silicon atom. x H y The carbon atom of the hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17.

6. The method of claim 1, wherein A 1 It is a secondary amine group, wherein the secondary amine group comprises a nitrogen atom bonded to a silicon atom and carbon atoms of two hydrocarbon functional groups, wherein each of the two hydrocarbon functional groups comprises the general formula C x H y , where x ranges from 1 to 8 and y ranges from 1 to 17.

7. The method of claim 1, wherein the thickness of the formed resist substrate is less than about 50 nanometers, such as less than about 20 nanometers, such as less than about 10 nanometers, such as less than about 5 nanometers, such as less than or about 3 nanometers.

8. A method for forming a resist underlayer on a substrate, the method comprising: The substrate is exposed to UV radiation in an atmosphere of resist underlay to form the resist underlay above the top surface of the substrate, the resist underlay comprising a compound having a structure represented by Formula I: Where R 1 R 2 and R 3 For each having the general formula C x H y Hydrocarbon functional groups, where x ranges from 1 to 8 and y ranges from 1 to 17, A 1 It is hydrogen or contains at least one of the following: C x H y The amine group of the hydrocarbon functional group, wherein x ranges between 1 and 8 and y ranges between 1 and 17.

9. The method of claim 8, wherein A 1 It is a primary amine group, wherein the primary amine group comprises a nitrogen atom, a hydrogen atom, and a atom having the general formula C bonded to a silicon atom. x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17.

10. The method of claim 8, wherein the thickness of the formed resist substrate is less than about 50 nanometers, such as less than about 20 nanometers, such as less than about 10 nanometers, such as less than about 5 nanometers, such as less than or about 3 nanometers.

11. A method for forming a resist underlayer over a substrate within a processing chamber, the method comprising: The substrate is positioned in the processing area of ​​the processing chamber; A resist underlayer is introduced into the treatment area, the resist underlayer comprising a compound having a structure represented by Formula I: Where R 1 R 2 , and R 3 For each having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17, and A 1 It is a hydrogen or amine group; as well as The substrate is exposed to the resist underlayer to deposit the resist underlayer on the top surface of the substrate.

12. The method of claim 11, wherein exposing the substrate to the resist underlayer further comprises: The substrate is exposed to UV radiation in the atmosphere of the resist underlayer.

13. The method of claim 12, wherein exposing the substrate to UV radiation further comprises: The processing chamber is configured to output UV power between approximately 1% and approximately 100%.

14. The method of claim 11, wherein R 1 R 2 , and R 3 All or some of them are the same functional groups.

15. The method of claim 11, wherein the resist underlayer is flowed together with a carrier gas comprising He or Ar.

16. The method of claim 11, wherein the temperature in the processing chamber is about 40°C to about 500°C.

17. The method of claim 11, wherein the resist underlayer is heated as it flows into the processing chamber.

18. The method of claim 11, wherein the thickness of the formed resist substrate is less than about 50 nanometers, such as less than about 20 nanometers, such as less than about 10 nanometers, such as less than or about 3 nanometers.

19. The method of claim 11, wherein A 1 It is a primary amine group, such that the resist underlayer contains a structure represented by Formula II: ,and Where R 4 For having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17.

20. The method of claim 11, wherein A 1 It is a secondary amine group, such that the resist underlayer contains a structure represented by Formula II: ,and Where R 4 and R 5 For each having the general formula C x H y The hydrocarbon functional group, wherein x ranges from 1 to 8 and y ranges from 1 to 17.

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