Spin-on carbon composition and method of manufacturing a semiconductor device

Abstract

A method of manufacturing a semiconductor device includes forming a spin-on carbon layer including a spin-on carbon composition on a semiconductor substrate. The spin-on carbon layer is first heated at a first temperature to partially crosslink the spin-on carbon layer. The spin-on carbon layer is second heated at a second temperature to further crosslink the spin-on carbon layer. A cap layer is formed on the spin-on carbon layer. The second temperature is higher than the first temperature.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a spin-on carbon composition and a method of fabricating a semiconductor device. BACKGROUND

[0002] The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs having smaller and more complex circuits. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functionality densities (i.e., the number of interconnected devices per chip area) generally have increased, while geometry sizes (i.e., the smallest component (or line) that can be created using a manufacturing process) have decreased. Shrinking the geometry size generally benefits production efficiency and lowers associated costs. Such shrinking also increases the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In one example, advanced photolithographic patterning techniques are implemented to form various patterns, such as gate electrodes and metal lines, on a semiconductor wafer. Photolithographic patterning techniques include applying a resist material on a bottom layer located on a surface of a semiconductor wafer. SUMMARY

[0003] According to some embodiments of the present disclosure, a method of fabricating a semiconductor device includes forming a spin-on carbon layer including a spin-on carbon composition on a semiconductor substrate; first heating the spin-on carbon layer at a first temperature to partially crosslink the spin-on carbon layer; second heating the spin-on carbon layer at a second temperature higher than the first temperature to further crosslink the spin-on carbon layer; and forming a capping layer on the spin-on carbon layer.

[0004] According to some embodiments of the present disclosure, a method of fabricating a semiconductor device includes forming a bottom layer on a semiconductor substrate, wherein the bottom layer includes: a carbon backbone polymer; a first crosslinking agent; and a second crosslinking agent; first heating the bottom layer at a first temperature to partially crosslink the bottom layer by the first crosslinking agent; second heating the bottom layer at a second temperature higher than the first temperature to further crosslink the bottom layer by the second crosslinking agent; forming an intermediate layer on the bottom layer; and forming a photoresist layer on the intermediate layer, wherein the intermediate layer has a composition different from the bottom layer and the photoresist layer.

[0005] According to some embodiments of the present disclosure, a spin-on carbon composition includes a carbon backbone polymer, a first crosslinking agent, and a second crosslinking agent. The first crosslinking agent reacts with the carbon backbone polymer at a first temperature to partially crosslink the carbon backbone polymer into a first polymer, and the second crosslinking agent reacts with the first polymer at a second temperature higher than the first temperature to further crosslink the carbon backbone polymer. BRIEF DESCRIPTION OF DRAWINGS

[0006] An embodiment of the disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that various features are not to scale and are shown for illustrative purposes only. In fact, the dimensions of the various features can be arbitrarily increased or decreased for the clarity of discussion.

[0007] Figure 1 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0008] Figure 2 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0009] Figure 3 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0010] Figure 4 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0011] Figure 5 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0012] Figure 6A and 6B Process stages illustrating a series of operations, in accordance with some embodiments of the disclosure;

[0013] Figure 7 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0014] Figure 8 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0015] Figure 9 Examples of cross-linking operations, in accordance with some embodiments of the disclosure;

[0016] Figure 10 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0017] Figure 11 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0018] Figure 12 Cross-sectional views illustrating a series of operations of fabricating a semiconductor device, in accordance with an embodiment of the disclosure;

[0019] Figure 13FIG. 1 illustrates cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0020] Figure 14 FIG. 2 illustrates cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0021] Figure 15 FIG. 3 illustrates cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0022] Figure 16 FIG. 4 illustrates cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0023] Figure 17 FIG. 5 illustrates cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0024] Figure 18 FIG. 6 illustrates cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0025] Figure 19A 、 19B FIGS. 19C and 19D illustrate cross-sectional views of a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure;

[0026] Figure 20 FIG. 20 shows a process flow of a method of fabricating a semiconductor device according to some embodiments of the present disclosure;

[0027] Figure 21 FIG. 21 shows a process flow of a method of fabricating a semiconductor device according to some embodiments of the present disclosure;

[0028] In the figures, the following symbols are used:

[0029] 10: substrate 15, 15a, 15b: spin-on carbon layer

[0030] 20: upper layer 20a: unexposed region

[0031] 20b: exposed region 25, 25a, 25b: mask

[0032] 30: radiation 35, 35', 35", 35'", 35": pattern

[0033] 40: mask substrate 45: opaque pattern

[0034] 50: layer to be patterned 55: low thermal expansion substrate

[0035] 60: reflective multilayer 70: buffer layer

[0036] 75: absorbing layer 80: backside reflective layer

[0037] 85: extreme ultraviolet radiation 90: radiation

[0038] 95: intermediate layer 100: photoresist layer

[0039] 105: patterned substrate 105a: main pattern area

[0040] 105b: rough pattern area 200: method

[0041] S210, S220, S230, S240: operations 300: method

[0042] S305, S310, S315, S320, S325, S330, S335, S340, S345, S350: operations

[0043] W1, W2: distance. DETAILED DESCRIPTION

[0044] The embodiments disclosed below provide numerous different embodiments, or examples, for implementing various features of the provided subject matter. Specific examples of elements and arrangements are described below to simplify the present case. Of course, these are merely examples and are not intended to be limiting. For example, the use of a first feature on or above a second feature in the following description can include embodiments where the first feature is formed directly on the second feature, and can also include embodiments where additional features can be formed between the first feature and the second feature such that the first feature and the second feature can not be directly in contact. Furthermore, element numbers and / or letters can be repeated in various examples. Such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and / or arrangements discussed.

[0045] In addition, spatially relative terms, such as "beneath", "below", "lower", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0046] Spin-on carbon (SOC) materials are used as anti-reflective layers, to planarize uneven surface topography, or as a bottom layer of a three-layer resist layer in semiconductor manufacturing processes. In some embodiments, a spin-on carbon material is coated on a substrate and then can undergo a cross-linking operation between a polymer and a cross-linking agent. The cross-linking operation can be a thermal cross-linking operation. The spin-on carbon is heated to initiate the thermal cross-linking operation. However, the heating can cause the spin-on carbon layer to reflow and result in undercoating or uneven coating of the underlying substrate or surface topography features on the substrate surface. Undercoating or uneven coating can result in damage to the substrate or features on the substrate during subsequent process operations (e.g., etching).

[0047] Embodiments of the present disclosure include a novel spin-on carbon composition and a method of inhibiting reflow of a spin-on carbon layer during a thermal cross-linking operation. Embodiments of the present disclosure include a two-stage heating operation to thermally cross-link a spin-on carbon layer. In a first stage, the spin-on carbon layer is heated at a first temperature to initiate a first cross-linking in the spin-on carbon composition, partially cross-linking a polymer in the spin-on carbon layer. The partial cross-linking reduces reflow of the spin-on carbon layer. The first heating is followed by a second heating at a second temperature higher than the first temperature to initiate a second cross-linking to further cross-link the spin-on carbon layer. Because the spin-on carbon has been partially cross-linked in the first heating operation, reflow of the spin-on carbon layer is reduced during the second cross-linking at a higher temperature. In some embodiments, the second cross-linking operation fully cross-links the spin-on carbon layer.

[0048] Figures 1-8 Cross-sectional views illustrating a series of operations for fabricating a semiconductor device according to an embodiment of the present disclosure are shown. Figure 1 A spin-on carbon layer 15 is shown formed on a substrate 10 (e.g., a wafer). In some embodiments, the spin-on carbon layer 15 is deposited from a liquid mixture and the substrate 10 is rotated as the spin-on carbon layer is deposited on the substrate 10. In some embodiments, the substrate 10 includes wiring patterns, transistors, or any other surface topography features.

[0049] In some embodiments, the substrate 10 includes a single-crystal semiconductor layer on at least a portion of its surface. The substrate can include a single-crystal semiconductor material such as, but not limited to, Si, Ge, SiGe, GaAs, InSb, GaP, GaSb, InAlAs, InGaAs, GaSbP, GaAsSb, and InP. In some embodiments, the substrate is a silicon layer of a silicon-on-insulator (SOI) substrate. In particular embodiments, the substrate is made of crystalline silicon. In particular embodiments, the substrate is a silicon wafer.

[0050] The substrate 10 may include one or more buffer layers (not shown) in its surface region. The buffer layers help to gradually change the lattice constant from the substrate to the source / drain regions of subsequent passes. The buffer layers may be formed from epitaxially grown single-crystal semiconductor materials, such as, but not limited to, Si, Ge, SiGe, GaAs, InSb, GaP, GaSb, InAlAs, InGaAs, GaSbP, GaAsSb, GaN, GaP, and InP. In one embodiment, the silicon-germanium buffer layer is epitaxially grown on a silicon substrate. The germanium concentration of the silicon-germanium buffer layer may be increased from 30 atomic% in the bottom buffer layer to 70 atomic% in the top buffer layer.

[0051] In some embodiments, the substrate comprises at least one metal, metal alloy, and a metal / nitride / sulfide / oxide / silicide having the chemical formula MXa, wherein M is a metal, X is N, S, Se, O, or Si, and a ranges from about 0.4 to about 2.5. In some embodiments, the substrate comprises titanium, aluminum, cobalt, ruthenium, titanium nitride, tungsten nitride, tantalum nitride, and combinations thereof.

[0052] In some embodiments, the substrate 10 includes a dielectric layer having at least the chemical formula MXb, comprising silicon, metal oxide, and silicon, metal nitride, wherein M is a metal or silicon, X is nitrogen or oxygen, and b ranges from about 0.4 to about 2.5. In some embodiments, Ti, Al, Hf, and Zr are suitable metals M. In some embodiments, the substrate comprises silicon dioxide, silicon nitride, aluminum oxide, hafnium oxide, and combinations thereof.

[0053] In some embodiments, the spin-coated carbon layer 15 comprises a polymer containing a carbon backbone, a first crosslinking agent, and a second crosslinking agent spin-coated carbon composite.

[0054] In some embodiments, the first crosslinking agent is selected from A-(OR)x, A-(NR)x, and one or more of the group of A-(OH)x, A-(OR')x, A-(C=C)x, and A-(C≡C)x, where A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R' is an alkoxy, an alkenyl, or an alkynyl; and x ranges from 2 to 1,000. In some embodiments, R is (CH2)yCH3, where 0 < y < 14. In some embodiments, R and OR include a linear structure, a cyclic structure, or a three-dimensional structure. In some embodiments, the three-dimensional structure is selected from the group comprising norbornyl, adamantyl, basket-handle, isotricyclodecyl, cubanyl, and dodecahedral.

[0055] In some embodiments, the second crosslinking agent is one or more selected from the group comprising A-(OH)x, A-(OR')x, A-(C=C)x, and A-(C≡C)x, where A is a monomer, a multimer, or a polymer having a molecular weight ranging from 100 to 20,000; R' is an alkoxy, an alkenyl, or an alkynyl; and x ranges from 2 to 1,000. In some embodiments, R is (CH2)yCH3, where 0 < y < 14. In some embodiments, R and OR include a linear structure, a cyclic structure, or a three-dimensional structure. In some embodiments, the three-dimensional structure is selected from the group comprising norbornyl, adamantyl, basket-handle, isotricyclodecyl, cubanyl, and dodecahedral.

[0056] In some embodiments, the carbon backbone polymer contains crosslinking sites on the polymer. In some embodiments, the carbon backbone compound is a polyhydroxystyrene, a polyacrylate, or a polymethyl methacrylate.

[0057] In some embodiments, the first and second crosslinking agents have a concentration ranging from about 20 wt.% to about 50 wt.% of the total weight of the first and second crosslinking agents and the carbon backbone polymer. In some embodiments, less than 20 wt.% of crosslinking agents results in insufficient crosslinking. In some embodiments, more than 50 wt.% of crosslinking agents does not provide an improvement in crosslinking, or the improvement is negligible. In some embodiments, the first crosslinking agent has a concentration ranging from about 5 wt.% to about 40 wt.% of the total weight of the first and second crosslinking agents and the carbon backbone polymer. In some embodiments, the second crosslinking agent has a concentration ranging from about 5 wt.% to about 40 wt.% of the total weight of the first and second crosslinking agents and the carbon backbone polymer. In some embodiments, the concentration of the first crosslinking agent is about the same as the concentration of the second crosslinking agent.

[0058] In some embodiments, the spin-on carbon composition includes a solvent. In some embodiments, the solvent is selected to enable the polymer and crosslinking agent to be uniformly dissolved in the solvent and dispensed onto the substrate.

[0059] In some embodiments, the solvent is an organic solvent and includes one or more of any suitable solvent, such as ketones, alcohols, polyols, ethers, glycol ethers, cyclic ethers, aromatic hydrocarbons, esters, propionic acid esters, lactic acid esters, lactate esters, alkylene glycol monoalkyl ethers, alkyl lactate esters, alkyl alkoxypropionic acid esters, cyclic lactone esters, cyclic-containing monoketone compounds, alkylene carbonate esters, alkyl alkoxyacetic acid esters, alkyl pyruvic acid esters, lactate esters, glycol alkyl ether acetates, propylene glycol alkyl ether acetates, alkylene glycol alkyl ether esters, alkylene glycol monoalkyl esters, and the like.

[0060] Specific examples of materials that can be used as solvents for spin-on carbon compositions include acetone, methanol, ethanol, propanol, isopropanol (IPA), n-butanol, toluene, xylene, 4-hydroxy-4-methyl-2-pentanone, tetrahydrofuran (THF), methyl ethyl ketone, cyclohexanone (CHN), methyl isobutyl ketone, 2-heptanone (MAK), ethylene glycol, 1-ethoxy-2-propanol, methyl isobutyl carbinol (MIBC), ethylene glycol monoacetate, ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, 2-hydroxypropionic acid ethyl ester, 2-hydroxy-2-methylpropionic acid methyl ester, 2-hydroxy-2-methylpropionic acid ethyl ester, ethoxyacetic acid ethyl ester, hydroxyacetic acid ethyl ester, 2-hydroxy-2-methylbutyric acid methyl ester, 3-methoxypropionic acid methyl ester, 3-methoxypropionic acid ethyl ester, 3-ethoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, acetic acid methyl ester, acetic acid ethyl ester, acetic acid propyl ester, acetic acid n-butyl ester (nBA), lactic acid methyl ester, lactic acid ethyl ester (EL), lactic acid propyl ester, lactic acid butyl ester, propylene glycol, propylene glycol monoacetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monopropyl methyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, propylene glycol monomethyl ether acetate, propylene glycol ethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethyl 3-ethoxypropionate, 3-methoxypropionate, 3-ethoxypropionate, 3-methoxypropyl acetate, β-propiolactone, β-butyrolactone, γ-butyrolactone (GBL), α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-octanoic lactone, α-hydroxy-γ-butyrolactone, 2-butanone, 3-methylbutanone, tertiary butyl methyl ketone, 2-pentanone, 3-pentanone, 4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone 3-decanone, 4-decanone, 5-hexen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, 3-methylcycloheptanone, propylene carbonate, vinylene carbonate, ethylene carbonate, butylene carbonate, acetate-2-methoxyethyl, acetate-2-ethoxyethyl, acetate-2-(2-ethoxyethoxy)ethyl, acetate-3-methoxy-3-methylbutyl, acetate-1-methoxy-2-propyl, dipropylene glycol, monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, monophenyl ether, monopropylene glycol monoacetate, dioxane, methyl pyruvate, ethyl pyruvate, propyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, n-methyl pyrrolidone (NMP), 2-methoxyethyl ether (diglyme), ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methyl propionate, ethyl propionate, ethyl ethoxypropionate, methyl ethyl ketone, cyclohexanone, 2-heptanone, cyclopentanone, cyclohexanone, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate (PGMEA), methylene glycol, 2-ethoxyethanol, N-methyl formamide, N,N-dimethyl formamide (DMF), N-methyl formanilide, N-methyl acetamide, N,N-dimethyl acetamide, dimethyl sulfoxide, benzyl ethyl ether, dihexyl ether, acetylacetone, isophorone, hexanoic acid, octanoic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, phenyl cellosolve acetate, and the like.

[0061] As will be appreciated by one of ordinary skill in the art, the above-listed and described materials that are exemplary of solvents that can be used to form the spin-on carbon composition are merely illustrative and are not intended to limit the embodiments. Rather, any suitable material that dissolves the carbon backbone polymer and the crosslinking agent can be used to facilitate mixing and application of the spin-on carbon layer. All such materials are expressly intended to be within the scope of the embodiments.

[0062] In some embodiments, the spin-on carbon layer 15 is formed to a thickness ranging from about 200 nm to about 2000 nm. In some embodiments, the thickness of the spin-on carbon layer 15 ranges from about 400 nm to about 1500 nm, and in other embodiments, the thickness of the spin-on carbon layer 15 ranges from about 500 nm to about 1200 nm, depending on the underlying structure (topology), design requirements, and / or process requirements.

[0063] In some embodiments, the spin-on carbon layer 15 is subjected to a first heat at a temperature ranging from about 100 °C to about 170 °C to form a partially crosslinked spin-on carbon layer 15a, as shown in Figure 2 In some embodiments, the first heat is at a temperature ranging from 100 °C to about 150 °C.

[0064] The viscosity of the spin-on carbon composition is selected to provide a target thickness when it is spun on a substrate. In some embodiments, the spin-on carbon composition has a viscosity of about 0.1 to about 1 x 106Pa-s at about 20 °C and is spun on a substrate at a spin rate of about 1500 rpm. In some embodiments, a first heating at about 100 °C to about 170 °C causes partial polymer crosslinking and increases the viscosity from about 0.1 1 x 106Pa-s to about 100 Pa-s to about 1 x 108Pa-s. A second heating at about 170 °C to about 300 °C causes further polymer crosslinking and increases the viscosity from about 100 Pa-s to about 1 x 108Pa-s to a solid layer. A first heating temperature below about 100 °C can result in insufficient partial crosslinking. A first heating temperature above about 170 °C can result in negligible increase in partial crosslinking or can prematurely trigger the second crosslinking. In some embodiments, the spin-on carbon layer 15 is heated at the first temperature for about 10 seconds to about 5 minutes to partially crosslink the spin-on carbon layer 15. In some embodiments, the first heating is performed for about 30 seconds to about 3 minutes. In some embodiments, the second heating is performed for about 30 seconds to 3 minutes.

[0065] After the first heating, the spin-on carbon layer 15 is allowed to cool at about 20 °C to about 25 °C for about 10 seconds to about 1 minute. The spin-on carbon layer 15a is then successively subjected to a second heating at a second temperature higher than the first temperature to form a further or fully crosslinked spin-on carbon layer 15b, as shown in Figure 3 some embodiments, the second temperature ranges from about 170 °C to about 300 °C. In some embodiments, the second temperature ranges from about 180 °C to about 300 °C. In some embodiments, the second temperature ranges from about 200 °C to about 280 °C. A second heating below about 170 °C can result in insufficient crosslinking. A second heating above about 300 °C can result in the spin-on carbon layer reflowing or an unacceptable increase in decomposition or cracking of the organic material forming the spin-on carbon layer 15b. In some embodiments, the spin-on carbon layer 15a is heated at the second temperature for about 30 seconds to about 3 minutes. In some embodiments, the second heating is performed for about 30 seconds to about 2 minutes. After the second heating, the spin-on carbon layer 15 is allowed to cool at about 20 °C to about 25 °C for about 10 seconds to about 1 minute before a subsequent process is performed on the substrate having the spin-on carbon layer 15b coated thereon.

[0066] The upper layer 20 is then formed over the crosslinked spin-on carbon layer 15b, as shown in Figure 4 some embodiments, the upper layer 20 is a photoresist layer, a hard mask layer, a polymer layer, or any other suitable layer. In some embodiments, the upper layer 20 is a photoresist layer made from a photoresist composition. In some embodiments, the substrate 10 is rotated (spun) during or after the deposition of the photoresist layer 10 to uniformly distribute the photoresist composition across the surface of the crosslinked spin-on carbon layer 15b.

[0067] The photoresist layer 20 is a photosensitive layer that is patterned by exposure to actinic radiation and development. Generally, the way in which the chemical properties of the photoresist region impacted by the incident radiation change depends on the type of photoresist used. The photoresist is positive tone or negative tone depending on the type of developer used to develop the photoresist. For example, some positive tone photoresists provide a positive pattern (i.e., the exposed regions are removed by the developer) when the developer is an aqueous developer such as tetramethylammonium hydroxide (TMAH). On the other hand, the same photoresist provides a negative pattern (i.e., the unexposed regions are removed by the developer) when the developer is an organic solvent. Additionally, in some negative tone photoresists developed with TMAH solvent, the unexposed regions of the photoresist are removed by the TMAH, while the exposed regions of the photoresist undergo crosslinking upon exposure to actinic radiation, remaining on the substrate after development.

[0068] According to the present disclosure, in some embodiments, the developer includes a polymer along with one or more photoactive compounds (PACs) in a solvent. In some embodiments, the polymer includes one or more groups (e.g., acid-labile groups) that will decompose or otherwise react when mixed with an acid, base, or radical generated by the PACs (as described further below) within a hydrocarbon structure (e.g., an alicyclic hydrocarbon structure). In some embodiments, the hydrocarbon structure includes repeating units that form the backbone of the polymer. The repeating units can include acrylate, methacrylate, crotonate, vinyl ester, maleate diester, fumarate diester, itaconate diester, (meth)acrylonitrile, (meth)acrylamide, styrene, vinyl ether, combinations of these, and the like.

[0069] The decomposing group, also referred to as a leaving group, or in embodiments where the PACs are photoacid generators, an acid-labile group, is attached to the hydrocarbon structure such that it will react with the acid / base / radical generated by the PACs during exposure.

[0070] In some embodiments, the polymer is a polyhydroxystyrene, a polyacrylate, or a polymethyl methacrylate-based polymer.

[0071] Additionally, some embodiments of the photoresist include one or more photoactive compounds (PACs). The PACs are photoactive ingredients such as photoacid generators, photobase generators, radical generators, and the like. The PACs can be positive- or negative-acting.

[0072] In some embodiments, a crosslinker is added to the photoresist composition. The crosslinker reacts with one group of a hydrocarbon structure in the polymer resin and also with a second group of a separate hydrocarbon structure to crosslink and link the two hydrocarbon structures together. This linking and crosslinking increases the molecular weight of the crosslinked polymer product of the crosslinking reaction and increases the overall link density of the photoresist. This increase in density and link density helps improve the photoresist pattern.

[0073] Alternatively, in addition to adding a crosslinking agent to the photoresist composition, in some embodiments, a coupling agent is added instead of or in addition to the crosslinking agent, where the coupling agent is added in addition to the crosslinking agent. The coupling agent aids the crosslinking reaction by reacting with the group on the hydrocarbon structure in the polymer resin prior to the crosslinking agent, allowing the reaction energy of the crosslinking reaction to decrease and the reaction rate to increase. The bound coupling agent then reacts with the crosslinking agent, thus coupling the crosslinking agent to the polymer resin.

[0074] Alternatively, in some embodiments where a coupling agent is added to the photoresist without a crosslinking agent, the coupling agent is used to couple a group of one hydrocarbon structure to a second group of a separate hydrocarbon structure to crosslink and link two polymers together. However, in such embodiments, the coupling agent does not remain as part of the polymer as the crosslinking agent, but merely assists in linking one hydrocarbon structure directly to another hydrocarbon structure.

[0075] Some embodiments of the photoresist are metal-containing photoresists. In some embodiments, the metal-containing photoresist forms a metal-containing photoresist layer. In some embodiments, the metal in the metal-containing photoresist includes one or more of Cs, Ba, La, Ce, In, Sn, or Ag.

[0076] In some embodiments, the metal-containing photoresist includes metal oxide nanoparticles. In some embodiments, the metal oxide nanoparticles are selected from the group consisting of titanium dioxide, zinc oxide, zirconium dioxide, nickel oxide, cobalt oxide, manganese oxide, copper oxide, iron oxide, strontium titanate, tungsten oxide, vanadium oxide, chromium oxide, tin oxide, ha oxide, indium oxide, cadmium oxide, molybdenum oxide, tantalum oxide, niobium oxide, aluminum oxide, and combinations thereof. Herein, nanoparticles are particles having an average particle size between 1 and 10 nm. In some embodiments, the metal oxide nanoparticles have an average particle size between 2 and 5 nm. In some embodiments, the amount of metal oxide nanoparticles in the photoresist composition ranges from about 1 wt.% to about 10 wt.% of the total weight of the photoresist composition. In some embodiments, less than 1 wt.% of metal oxide nanoparticles provides a photoresist layer that is too thin, and more than 10 wt.% of metal oxide nanoparticles provides a photoresist composition that is too viscous and will be difficult to provide a uniform thickness of photoresist coating on a substrate.

[0077] In some embodiments, metal oxide nanoparticles are liganded with carboxylic acid or sulfonic acid ligands. For example, in some embodiments, zirconium oxide or hafnium oxide nanoparticles are liganded with methacrylic acid to form methacrylic acid (HfMAA) or zirconium methacrylate (ZrMAA). In some embodiments, HfMAA and ZrMAA are dissolved in a coating solvent (e.g., propylene glycol methyl ether acetate (PGMEA)) at a weight range of about 5 wt.% to about 10 wt.%. In some embodiments, a photosensitive compound (PAC) comprising about 1 wt.% to about 10 wt.% of the total weight of the photoresist composition forms the metal oxide photoresist.

[0078] The various components of the photoresist composition are placed in a solvent to aid in the mixing and distribution of the photoresist. To facilitate the mixing and distribution of the photoresist, the solvent is selected based at least in part on the materials chosen for the polymer and the PAC. In some embodiments, the solvent is selected such that the polymer resin and the PAC can be uniformly dissolved in the solvent and distributed onto the layer to be patterned. In some embodiments, the solvent is an organic solvent and includes one or more solvents disclosed herein as suitable solvents for the SOC composition.

[0079] In some embodiments, the method includes, after the photoresist layer 20 is placed on the SOC layer 15b, subjecting the photoresist layer 20 and the SOC layer 15b to a third heating at a temperature of about 40°C to about 140°C for 10 seconds to 5 minutes. The third heating removes solvent from the photoresist layer. In some embodiments, the photoresist layer 20 and the SOC layer 15b are heated at a temperature of about 60°C to about 120°C for 20 seconds to 3 minutes.

[0080] Next, as Figure 5 As shown, a portion of the photoresist layer 20b is selectively exposed to photochemical radiation 30. In some embodiments, the mask 25 is used to form the exposed portion 20b and the unexposed portion 20a of the photoresist layer.

[0081] Figure 6A and 6B This is a detailed view illustrating the selective exposure of the photoresist layer 20 to form exposed regions 20b and unexposed regions 20a. In some embodiments, exposure to radiation is achieved by placing the photoresist-coated substrate in a photolithography tool. The photolithography tool includes masks 25a and 25b, optical elements, an exposure radiation source providing radiation 30 / 90 for exposure, and a movable platform for supporting and moving the substrate under the exposure radiation.

[0082] In some embodiments, a radiation source (not shown) supplies radiation 30 / 90 (such as ultraviolet light) to the photoresist layer 20 to initiate a reaction of the photosensitive composite in the photoresist, which in turn reacts with the polymer in the photoresist to chemically alter the region of the photoresist layer 20b impacted by the radiation 30 / 90. In some embodiments, the radiation is electromagnetic radiation, such as gamma rays (wavelength about 436 nm), i rays (wavelength about 365 nm), ultraviolet radiation, far ultraviolet radiation, extreme ultraviolet radiation, electron beams, etc. In some embodiments, the radiation source is selected from the group consisting of mercury vapor lamps, xenon lamps, carbon arc lamps, KrF excimer lasers (wavelength 248 nm), ArF excimer lasers (wavelength 193 nm), F2 excimer lasers (wavelength 157 nm), or Sn plasma excited by a CO2 laser (extreme ultraviolet, wavelength 13.5 nm).

[0083] In some embodiments, optical elements (not shown) are used in a photolithography tool to amplify, reflect, or control radiation 30 / 90 before and after it is patterned by masks 25a / 25b. In some embodiments, the optical elements include one or more lenses, mirrors, filters, and combinations thereof to control radiation 30 / 90 along its path.

[0084] In some embodiments, the patterned radiation 30 / 90 is extreme ultraviolet light with a wavelength of 13.5 nm, the photosensitive compound (PAC) is a photoacid generator, and the groups to be decomposed are acid-indestructible (ALG) side chains of the polymer's hydrocarbon backbone structure. In some embodiments, a crosslinking agent is used. The patterned radiation 30 / 90 impacts the photoacid generator, which absorbs the impacting patterned laser radiation 30 / 90. This absorption initiates the photoacid generator to generate protons (e.g., H+ atoms) in the photoresist layer 20b. When the protons affect the ALG on the hydrocarbon structure, the protons react with the ALG, chemically altering the ALG and substantially changing the polymer properties. The acid generated by the photoacid generator in the photoresist 20 cleaves the ALG on the polymer through the side-chain ALG, thereby increasing the polymer's solubility in the developer.

[0085] like Figure 6A As shown, in some embodiments, exposure radiation 30 passes through mask 25a in front of the illuminating photoresist layer 20. In some embodiments, the mask has a pattern to be reproduced in the photoresist layer 20. In some embodiments, the pattern is formed by an opaque pattern 45 on the mask substrate 40. In some embodiments, the opaque pattern 45 may be formed of a material transparent to ultraviolet radiation, such as chromium, while the mask substrate 40 may be formed of a material transparent to ultraviolet radiation, such as fused silica.

[0086] In some embodiments, the selective exposure of the photoresist layer 20 to form exposed regions 20b and unexposed regions 20a is performed using extreme ultraviolet lithography. In an extreme ultraviolet lithography operation, a reflective mask 25b is used to form a patterned exposure beam as shown in Figure 6B The reflective mask 25b includes a low thermal expansion glass substrate 55 on which a reflective multilayer 60 of Si and Mo is formed. A capping layer 70 and an absorbing layer 75 are formed on the reflective multilayer 60. A backside reflective layer 80 is formed on the backside of the low thermal expansion substrate 55. In extreme ultraviolet lithography, extreme ultraviolet radiation 85 is directed at the reflective mask 25b at an angle of incidence of about 6°. A portion 90 of the extreme ultraviolet radiation is reflected by the Si / Mo reflective multilayer 60 toward the photoresist coated substrate 10, while a portion of the extreme ultraviolet radiation is absorbed by the mask, such as provided on the absorbing layer 75. In some embodiments, additional optical elements, including mirrors, are included between the reflective mask 25b and the photoresist coated substrate.

[0087] In some embodiments, the exposure of the resist layer 20 uses an immersion lithography technique. In this technique, an immersion medium (not shown) is placed between the terminal optical element and the photoresist layer 20, and the exposure radiation 30 passes through the immersion medium.

[0088] As a result of the exposure operation, a latent pattern is formed in the photoresist layer 20. The latent pattern of the photoresist layer 20, with reference to the exposed pattern in the photoresist layer 20, becomes a physical photoresist pattern through a development operation, for example. The latent pattern of the photoresist layer 20 includes unexposed portions 20a and exposed portions 20b. In embodiments using a chemically amplified (CA) resist material with a photoacid generator (PAG), acid is generated in the exposed portions 20b during the exposure process. In the latent pattern, the exposed portions 20b of the photoresist layer 20 are physically or chemically changed. In some examples, the exposed portions 20b are deprotected, thereby causing a polarity change for bi-tonal imaging (development).

[0089] In some embodiments, the selectively exposed photoresist layer 20 is then subjected to a fourth heating. The fourth heating of the selectively exposed photoresist layer, also referred to as a post-exposure bake (PEB) operation, is performed at a temperature of about 80 °C to about 300 °C for about 10 seconds to about 10 minutes. In some embodiments, the PEB is performed at a temperature of about 100 °C to about 200 °C for about 10 seconds to about 10 minutes. During the PEB operation, more acid is generated in the exposed portions 20b of the photoresist layer. The generated acid promotes chemical changes in the photoresist layer and the photoresist underlayer. In some embodiments, crosslinking occurs during the PEB. In some embodiments, the PEB heating temperature is in the range of about 130 °C to about 170 °C for about 30 seconds to about 5 minutes.

[0090] In some embodiments, development is then performed, as shown in Figure 7As shown in FIG. 3, a solvent is used to form the pattern 35 in the photoresist overlying the SOC layer. In some embodiments, the SOC layer 15b is soluble in the photoresist developer. In other embodiments, a different solvent than the photoresist developer is used or the exposed portions of the SOC layer 15 are removed by etching after the photoresist layer is developed.

[0091] In some embodiments where positive development is used, a positive developer such as an aqueous alkaline solution is used to remove the radiation exposed portions 20b of the photoresist layer.

[0092] In some embodiments, the developer is applied to the photoresist layer using a spin coating process. In a spin coating process, the developer is applied to the photoresist layer from above by a dispenser while the coated substrate is rotated. In some embodiments, the developer is supplied at a rate of about 5 ml / min to about 800 ml / min while the coated substrate is rotated at a speed of about 100 rpm to about 2000 rpm. In some embodiments, the developer is at a temperature of about 10 °C to about 80 °C. In some embodiments, the development operation lasts for about 30 seconds to about 10 minutes.

[0093] Although a spin coating operation is one suitable method for developing the photoresist layer after exposure, it is intended to be exemplary and not intended to limit the embodiments. Rather, any suitable development operation can be used alternatively, including dip coating processes, mix and bake processes, and spray methods. All of these development operations are included within the scope of the embodiments.

[0094] In some embodiments, additional processes are performed after the patterned photoresist layer 20a and the SOC layer 15b are in place. For example, in some embodiments, an etching operation using dry etching or wet etching is performed to transfer the pattern 35 of the photoresist layer to the substrate 10, thereby forming a pattern 35' in the substrate. The remaining photoresist layer and the SOC layer are then removed by a suitable stripping, ashing, or etching operation, as shown in Figure 8 FIG. 4.

[0095] Figure 9 An example of a crosslinking operation according to embodiments of the disclosure is shown. In one embodiment, the SOC layer includes a host polymer, such as polyhydroxystyrene, a low activation energy (Ea) crosslinking agent having four alkoxy crosslinking groups, and a high activation energy (Ea) crosslinking agent having four hydroxyl groups. The SOC layer is subjected to a low temperature bake operation, such as heating at a temperature of about 130 °C, which triggers the low Ea crosslinking agent to partially crosslink the host polymer. Then, a high temperature bake operation, such as heating at a temperature of about 250 °C, is performed, which triggers the high Ea crosslinking agent to more completely crosslink the host polymer.

[0096] Figures 10-12 Cross-sectional views of alternative embodiments of manufacturing semiconductor devices according to the disclosure. Figure 10A semiconductor substrate 10 is shown having a layer 50 to be patterned disposed thereon, and a SOC layer 15 disposed over the layer 50 to be patterned. In some embodiments, the layer 50 to be patterned is a hard mask layer; a metallization layer; or a dielectric layer disposed over a metal layer, such as a passivation layer. In embodiments where the layer 50 to be patterned is a metallization layer, the layer 50 to be patterned is formed of a conductive material using metallization processes and metal deposition techniques including chemical vapor deposition, atomic layer deposition, and physical vapor deposition (sputtering). Likewise, if the layer 50 to be patterned is a dielectric layer, the layer 50 to be patterned can be formed by dielectric layer formation techniques including thermal oxidation, chemical vapor deposition, atomic layer deposition, and physical vapor deposition.

[0097] Subsequently, the substrate 10 having the layer 50 to be patterned and the SOC layer 15 thereon is processed in a manner similar to that discussed herein with reference to Figure 2 and Figure 3 to form a fully cross-linked SOC layer 15b, as shown. Figure 11 The structure of Figures 4-7 is then processed in a manner similar to that discussed herein with reference to Figure 11 and the substrate 10 having the layer 50 to be patterned is etched using the photoresist layer / SOC layer pattern 35 as an etch mask. Figure 12 As shown, a pattern 35" is formed in the layer 50 to be patterned. The layer 50 to be patterned can be etched by wet etching or dry etching, depending on the material to be etched and the desired configuration of the pattern 35".

[0098] Figures 13-18 is a cross-sectional view of an alternative embodiment of fabricating a semiconductor device according to the present disclosure. In some embodiments, a SOC layer 15 is disposed over a selective layer 50 to be patterned, which is disposed over a substrate 10. The SOC layer-coated substrate is then processed in a manner similar to that discussed herein with reference to Figure 2 and Figure 3 or Figure 10 and Figure 11 to form a fully cross-linked SOC layer 15b, as shown. Figure 14

[0099] In some embodiments, the fully cross-linked SOC layer 15b is a bottom layer of a three-layer resist. As shown, a middle layer 95 of the three-layer resist and a photoresist layer 100 are then disposed over the bottom layer 15b. Figure 15

[0100] ​​The middle layer 95 of the three-layer resist structure can have a composition that provides antireflective properties and / or hardmask properties for the lithographic operation. In some embodiments, the middle layer 95 includes a silicon-containing layer (e.g., a silicon hardmask material). The middle layer 95 can include a silicon-containing inorganic polymer. In other embodiments, the middle layer 95 includes a siloxane polymer. In other embodiments, the middle layer 95 includes silicon oxide (e.g., spin-on glass (SOG)), silicon nitride, silicon oxynitride, polysilicon, a metal-containing organic polymer material including a metal (e.g., titanium, titanium nitride), aluminum, and / or tantalum; and / or other suitable materials. The middle layer 95 can be bonded to adjacent layers, e.g., by covalent bonds, hydrogen bonds, or hydrophilic-hydrophilic forces.

[0101] The photoresist layer 100 can include any of the photoresist compositions described above with reference to Figure 4 the disclosed photoresist compositions.

[0102] Figure 15 The structure is then processed in a similar manner as the methods disclosed above with reference to Figure 5 and Figure 7 to develop the photoresist layer 100. The selectively patterned layer 50 and the middle layer 95 and the bottom layer 15b are then etched using the patterned photoresist as an etch mask to form a pattern 35"' as shown in Figure 16 The middle layer 95 and the bottom layer 15b can be etched by wet etching or dry etching, depending on the material to be etched and the structure desired for the pattern 35"'. In some embodiments, the pattern 35"' in the middle layer 95 and the bottom layer 15b extends into the substrate 10 or the selectively patterned layer 50, and a suitable wet etching or dry etching operation is used to form a pattern 35"" in the selectively patterned layer 50 or the substrate 10 as shown in Figure 17 The remaining portions of the three-layer resist are then removed by one or more stripping or etching operations as shown in Figure 18 .

[0103] In some embodiments, a SOC layer 15 is formed over the patterned substrate 105 as shown in Figure 19A The patterned substrate 105 includes a main pattern region 105a in which the pattern features have a fine pitch and are spaced apart by a distance Wl, and a coarse pattern region 105b in which the pattern features are more widely spaced apart by a distance W2. In some embodiments, Wl is less than about 20 nm. In some embodiments, Wl ranges from about 5 nm to about 20 nm. In some embodiments, Wl ranges from about 10 nm to about 15 nm. In some embodiments, W2 is greater than about 80 nm. In some embodiments, W2 ranges from about 80 nm to about 200 nm. In some embodiments, W2 ranges from about 100 nm to about 150 nm.

[0104] Subsequently, Figure 19AThe structure is heated at a first heating temperature to form a partially cross-linked SOC layer 15a, such as Figure 19B As shown. Due to the sufficiently low initial heating temperature, reflow of the SOC layer 15a is minimal or nonexistent. Next, Figure 19B The structure is heated at a higher second temperature to form a further or fully cross-linked SOC layer 15b, such as Figure 19C As shown. The partially cross-linked SOC layer 15a resists reflow during the second heating at a higher temperature. Therefore, the SOC layer 15b maintains a sufficient height on the main patterned region 105a to protect the main patterned feature 105a during subsequent processes. Figure 19D As shown, after subsequent processes (such as etching), a portion of the SOC layer 15b remains on the main pattern. Therefore, because the reflow of the SOC layer is suppressed, the main pattern area 105a is protected from damage during subsequent process operations.

[0105] Figure 20 A flowchart illustrating method 200 according to an embodiment of the present disclosure is provided. In operation S210, a spin-coated carbon layer 15 is formed on a substrate 20. In operation S220, the spin-coated carbon layer 15 is first heated at a first temperature to partially crosslink the spin-coated carbon layer. Next, in operation S230, the spin-coated carbon layer 15a is second heated at a second temperature to further crosslink the spin-coated carbon layer 15b. The second temperature is higher than the first temperature. In operation S240, an upper layer 20 is formed over the spin-coated carbon layer. In some embodiments, the upper layer 20 is a photoresist layer, a hard mask layer, a polymer layer, or any other suitable layer.

[0106] Figure 21 A flowchart illustrating method 300 according to an embodiment of the present disclosure is provided. In operation S305, a substrate 15 is formed over semiconductor substrates 10 and 50. In some embodiments, substrate 15 includes a carbon backbone polymer, a first crosslinking agent, and a second crosslinking agent. In operation S310, substrate 15 is first heated at a first temperature to partially crosslink the substrate by the first crosslinking agent. In operation S315, substrate 15a is then second heated at a second temperature above the first temperature to further crosslink the substrate by the second crosslinking agent. In operation S320, an intermediate layer 95 is formed over substrate 15b, and in operation S325, a photoresist layer 100 is formed over intermediate layer 95. The intermediate layer has a different composition from the substrate and the photoresist layer. In some embodiments, photoresist layer 100 is selectively exposed to photochemical radiation in operation S320 and then developed in operation S325 to form a photoresist pattern. In operation S330, the pattern extends into intermediate layer 95 and substrate 15b to expose substrate 10. In some embodiments, substrates 10 and 50 are successively etched in operation S345, while the photoresist layer, intermediate layer and bottom layer are removed in operation S350.

[0107] In some embodiments, additional processing operations are performed to fabricate a semiconductor device. In some embodiments, the fabrication process includes applying an ion implantation process to the wafer using the patterned resist layer as an implant mask to form various doped features in the wafer.

[0108] Other embodiments include other operations before, during, or after the operations described above. In one embodiment, the method includes forming a fin field effect transistor (FinFET) structure. In some embodiments, a plurality of active fins are formed on a semiconductor substrate. Such embodiments further include etching the substrate through openings of the patterned hard mask to form trenches in the substrate; filling the trenches with a dielectric material; performing chemical mechanical polishing (CMP) to form shallow trench isolation (STI) features; and epitaxially growing or digging into the STI features to form fin-shaped active regions. In further embodiments, the method includes other operations to form a plurality of gate electrodes on the semiconductor substrate. The method can further include forming gate spacers, doped source / drain regions, gate / source / drain contacts, and the like. In still further embodiments, the target pattern is to be formed as metal lines in a multilayer interconnect structure. For example, the metal lines can be formed in an interlayer dielectric (ILD) layer of the substrate that has been etched to form a plurality of trenches. The trenches can be filled with a conductive material, such as a metal; and the conductive material can be polished, such as by chemical mechanical planarization, to expose the patterned ILD layer, thereby forming the metal lines in the ILD layer. The above are non-limiting examples of devices / structures that can be fabricated and / or improved using the methods described herein.

[0109] In some embodiments, the semiconductor substrate 10 is an intermediate structure fabricated during the fabrication of an IC or a portion of an IC, which can include logic circuits, memory structures, passive elements (such as resistors, capacitors, and inductors), and active elements (such as diodes, field effect transistors (FETs), metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar transistors, high voltage transistors, high frequency transistors, fin field effect transistors (FinFETs), other three-dimensional FETs, metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar transistors, high voltage transistors, high frequency transistors, other memory cells, and combinations thereof.

[0110] Embodiments of the present disclosure provide improved coverage and planarity by spin-on carbon layers. Spin-on carbon compositions and methods according to the present disclosure inhibit spin-on carbon layer reflow. By reducing spin-on carbon layer reflow, over-thin SOC layers on the substrate can be avoided. Thus, substrate damage or features formed on the substrate during subsequent processing of the photoresist device can be avoided.

[0111] One embodiment of the present disclosure is a method of fabricating a semiconductor device including forming a spin-on carbon layer including a spin-on carbon composition on a semiconductor substrate; first heating the spin-on carbon layer at a first temperature to partially crosslink the spin-on carbon layer; second heating the spin-on carbon layer at a second temperature to further crosslink the spin-on carbon layer; and forming a capping layer on the spin-on carbon layer, wherein the second temperature is higher than the first temperature. In one embodiment, the spin-on carbon composition includes a carbon backbone polymer, a first crosslinking agent, and a second crosslinking agent, wherein the first and second crosslinking agents are different from each other. In one embodiment, the first crosslinking agent is selected from one or more of the group including A-(OR) x , A-(NR) x , , wherein A is a monomer, multimer, or polymer having a molecular weight ranging from 100 to 20,000; R is a hydrocarbyl group, a cycloalkyl group, a cycloalkyl epoxy group, or a C3-C15 heterocyclic group; OR is an alkoxy group, a cycloalkoxy group, a carbonate group, an alkyl carbonate group, an alkyl carboxylate group, a tosylate group, or a mesylate group; NR is an alkyl amide group or an alkyl amino group; and x ranges from 2 to 1,000. In one embodiment, R, OR, and NR each include a chain structure, a ring structure, or a three-dimensional structure. In one embodiment, the second crosslinking agent is selected from one or more of the group including A-(OH) x , A-(OR') x , A-(C=C) x , and A-(C≡C) x , wherein A is a monomer, multimer, or polymer having a molecular weight ranging from 100 to 20,000; R' is an alkoxy group, an alkenyl group, or an alkynyl group; and x ranges from 2 to 1,000. In one embodiment, the concentrations of the first and second crosslinking agents in the spin-on carbon composition range from 20 wt.% to 50 wt.% of the total weight of the first and second crosslinking agents and the carbon backbone polymer. In one embodiment, during the first heating, the first crosslinking agent reacts with the carbon backbone polymer to partially crosslink the carbon backbone polymer. In one embodiment, during the second heating, the second crosslinking agent reacts with the first polymer to further crosslink the carbon backbone polymer. In one embodiment, the first temperature ranges from 100 °C to 170 °C. In one embodiment, the second temperature ranges from 180 °C to 300 °C. In one embodiment, the first temperature ranges from 100 °C to 150 °C. In one embodiment, the second temperature ranges from 200 °C to 280 °C. In one embodiment, the carbon backbone polymer is polyhydroxystyrene.

[0112] Another embodiment of the present disclosure is a method of fabricating a semiconductor device comprising forming a primer layer on a semiconductor substrate, wherein the primer layer comprises a carbon backbone polymer; a first crosslinking agent; and a second crosslinking agent; first heating the primer layer at a first temperature to partially crosslink the primer layer via the first crosslinking agent; second heating the primer layer at a second temperature higher than the first temperature to further crosslink the primer layer via the second crosslinking agent. Forming an intermediate layer on the primer layer; and forming a photoresist layer on the intermediate layer, wherein the intermediate layer has a different composition than the primer layer and the photoresist layer. In one embodiment, the first crosslinking agent is selected from one or more of the group comprising A-(OR) x , A-(NR) x , wherein A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R is a hydrocarbyl, a cycloalkyl, a cycloalkyl epoxy, or a C3-C15 heterocyclyl; OR is an alkoxy, a cycloalkoxy, a carbonate, an alkylcarbonate, an alkylcarboxylate, a tosylate, or a mesylate; NR is an alkylamide or an alkylamino; and x ranges from 2 to 1,000. In one embodiment, the second crosslinking agent is selected from one or more of the group comprising A-(OH) x , A-(OR') x , A-(C=C) x , and A-(C≡C) x wherein A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R' is an alkoxy, an alkenyl, or an alkynyl; and x ranges from 2 to 1,000. In one embodiment, the intermediate layer comprises at least one selected from the group comprising an inorganic polymer containing material, a siloxane polymer, a silicon oxide, a silicon nitride, a silicon oxynitride, a polysilicon, and a metal-containing organic polymer material. In one embodiment, the method further comprises selectively exposing the photoresist layer to actinic radiation; developing the selectively exposed photoresist layer to form a photoresist pattern; extending the pattern into the intermediate layer and the primer layer to expose the substrate; etching the substrate; and removing the photoresist layer, the intermediate layer, and the primer layer. In one embodiment, the first temperature ranges from 100°C to 170°C. In one embodiment, the first temperature ranges from 100°C to 150°C. In one embodiment, the second temperature ranges from 180°C to 300°C. In one embodiment, the second temperature ranges from 200°C to 280°C. In one embodiment, R, OR, and NR comprise a linear structure, a cyclic structure, or a three-dimensional structure. In one embodiment, the intermediate layer is a silicon-containing hardmask.

[0113] Another embodiment of this disclosure is a spin-coated carbon composite comprising a carbon backbone polymer; a first crosslinking agent; and a second crosslinking agent, wherein the first crosslinking agent reacts with the carbon backbone polymer at a first temperature to partially crosslink into a first polymer, and the second crosslinking agent reacts with the first polymer at a second temperature above the first temperature to further crosslink the carbon backbone polymer. In one embodiment, the first crosslinking agent is selected from A-(OR). x A-(NR) x , One or more of the group consisting of, wherein A is a monomer, polymer, or aggregate having a molecular weight ranging from 100 to 20,000; R is a hydrocarbon group, cycloalkyl group, cycloalkylepoxy group, or C3-C15 heterocyclic group; OR is an alkoxy group, cycloalkoxy group, carbonate group, alkyl carbonate group, alkyl carboxylate group, toluenesulfonate group, or methanesulfonate group; NR is an alkylamide group or alkylamino group; and x ranges from 2 to 1000. In one embodiment, the second crosslinking agent is selected from the group including A-(OH). x A-(OR') x A-(C=C) x and A-(C≡C) x One or more of the group consisting of, wherein A is a monomer, polymer, or polymer having a molecular weight ranging from 100 to 20,000; R' is alkoxy, alkenyl, or alkynyl; and x ranges from 2 to 1,000. In one embodiment, the concentration of the first and second crosslinking agents in the spin-coated carbon composite ranges from 20 wt.% to 50 wt.% of the total weight of the first and second crosslinking agents and the first polymer. In one embodiment, the spin-coated carbon composite further includes a solvent. In one embodiment, the carbon backbone polymer is polyhydroxystyrene. In one embodiment, R is (CH2). y CH3, where 0 ≤ y ≤ 14. In one embodiment, OR is (-O(CH2CH2O)a-CH2CH3), where 1 ≤ a ≤ 6. In one embodiment, R, OR, and NR comprise chain, cyclic, or three-dimensional structures. In one embodiment, the concentration of the first crosslinking agent is the same as the concentration of the second crosslinking agent. In one embodiment, the three-dimensional structure is selected from the group comprising norcamphenyl, adamantyl, basalyl, isotricyclodecyl, cubic, and dodecahedral groups.

[0114] Another embodiment of the present disclosure is a method of fabricating a semiconductor device comprising forming a primer layer on a semiconductor substrate, wherein the primer layer comprises a carbon backbone polymer; a first crosslinking agent; and a second crosslinking agent; first heating the primer layer at a first temperature to partially crosslink the primer layer via the first crosslinking agent; second heating the primer layer at a second temperature higher than the first temperature to further crosslink the primer layer via the second crosslinking agent. Forming an intermediate layer on the primer layer; and forming a photoresist layer on the intermediate layer, wherein the intermediate layer has a different composition than the primer layer and the photoresist layer. In one embodiment, the first crosslinking agent is selected from one or more of the group comprising A-(OR) x , A-(NR) x , wherein A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R is a hydrocarbyl group, a cycloalkyl group, a cycloalkyl epoxy group, or a C3-C15 heterocyclic group; OR is an alkoxy group, a cycloalkoxy group, a carbonate group, an alkyl carbonate group, an alkyl carboxylate group, a tosylate group, or a mesylate group; NR is an alkyl amide group or an alkyl amino group; and x ranges from 2 to 1,000. In one embodiment, the second crosslinking agent is selected from one or more of the group comprising A-(OH) x , A-(OR') x , A-(C=C) x , and A-(C≡C) x wherein A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R' is an alkoxy group, an alkenyl group, or an alkynyl group; and x ranges from 2 to 1,000. The primer layer is heated at a first temperature to partially crosslink the spin-on carbon layer via the first crosslinking agent. The spin-on carbon layer is heated at a second temperature higher than the first temperature to further crosslink the spin-on carbon layer via the second crosslinking agent, and the photoresist layer is formed on the spin-on carbon layer. In one embodiment, the method comprises selectively exposing the photoresist layer to actinic radiation; developing the selectively exposed photoresist layer to form a photoresist pattern exposing the substrate; and extending the pattern into the substrate. In one embodiment, the method comprises removing the photoresist pattern after extending the pattern into the substrate. In one embodiment, the carbon backbone polymer is polyhydroxystyrene. In one embodiment, the first temperature ranges from 100 °C to 170 °C. In one embodiment, the first temperature ranges from 100 °C to 150 °C. In one embodiment, the second temperature ranges from 180 °C to 300 °C. In one embodiment, the second temperature ranges from 200 °C to 280 °C. In one embodiment, R, OR, and NR comprise a linear structure, a cyclic structure, or a three-dimensional structure. In one embodiment, the three-dimensional structure is selected from the group comprising norbornyl, adamantyl, basket-handle, isotricyclodecyl, cubanyl, and dodecahedral.

[0115] The foregoing has outlined rather broadly the features of several embodiments in order that the detailed description that follows can be better understood. Those skilled in the art will appreciate that they can readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and / or achieving the same advantages of the embodiments introduced herein. Those skilled in the art will also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure and that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the disclosure.

Claims

1. A method of manufacturing a semiconductor element, characterized by, comprising: forming a spin-on carbon layer comprising a spin-on carbon composition on a semiconductor substrate; first heating the spin-on carbon layer at a first temperature to partially crosslink the spin-on carbon layer; second heating the spin-on carbon layer at a second temperature to further crosslink the spin-on carbon layer; and forming a cap layer over the spin-on carbon layer, wherein the second temperature is higher than the first temperature, wherein the spin-on carbon composition comprises a carbon backbone polymer, a first crosslinking agent, and a second crosslinking agent, wherein the first and second crosslinking agents are different from each other.

2. The method of claim 1, further comprising: forming an intermediate layer over the spin-on carbon layer, the cap layer being a photoresist layer formed on the intermediate layer, wherein the intermediate layer has a composition different from the spin-on carbon layer and the photoresist layer.

3. The method of claim 1, wherein the first crosslinking agent is selected from one or more of the group comprising A-(OR) x , A-(NR) x , and wherein A is a monomer, multimer, or polymer having a molecular weight ranging from 100 to 20,000; R is a hydrocarbyl, cycloalkyl, cycloalkyl epoxy, or C3-C15 heterocyclyl; OR is an alkoxy, cycloalkoxy, carbonate, alkyl carbonate, alkyl carboxylate, tosylate, or mesylate; NR is an alkyl amide or alkyl amino; and x ranges from 2 to 1,000.

4. The method of claim 3, wherein R, OR, and NR each comprises a chain structure, a ring structure, or a three-dimensional structure.

5. The method of claim 1, wherein the second crosslinking agent is selected from one or more of the group comprising A-(OH) x , A-(OR’) x , A-(C=C) x , and A-(C≡C) x , wherein A is a monomer, multimer, or polymer having a molecular weight ranging from 100 to 20,000; R’ is an alkoxy, alkenyl, or alkynyl group; and x ranges from 2 to 1,000.​​​​​​​​ 6. The method of claim 1, wherein the concentration of the first crosslinking agent and the second crosslinking agent in the spin-on carbon composition ranges from 20 wt.% to 50 wt.% of the total weight of the first crosslinking agent and the second crosslinking agent and the carbon backbone polymer.

7. The method of claim 1, wherein during the first heating, the first crosslinking agent reacts with the carbon backbone polymer to partially crosslink the carbon backbone polymer.

8. The method of claim 7, wherein during the second heating, the second crosslinking agent reacts with the first polymer to further crosslink the carbon backbone polymer.

9. The method of claim 1, wherein the first temperature ranges from 100 °C to 170 °C.

10. The method of claim 1, wherein the second temperature ranges from 180 °C to 300 °C.

11. A method of manufacturing a semiconductor element, characterized by, comprising: forming a bottom layer on a semiconductor substrate, wherein the bottom layer comprises: a carbon backbone polymer; a first crosslinking agent; and a second crosslinking agent; first heating the bottom layer at a first temperature to partially crosslink the bottom layer by the first crosslinking agent; second heating the bottom layer at a second temperature higher than the first temperature to further crosslink the bottom layer by the second crosslinking agent; forming an intermediate layer over the bottom layer; and forming a photoresist layer over the intermediate layer, wherein the intermediate layer has a composition different from the bottom layer and the photoresist layer.

12. The method of claim 11, wherein the first crosslinking agent is selected from one or more of the group comprising A-(OR) x , A-(NR) x , and ​ wherein A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R is a hydrocarbyl group, a cycloalkyl group, a cycloalkyl epoxy group, or a C3-C15 heterocyclyl group; OR is an alkoxy group, a cycloalkoxy group, a carbonate group, an alkyl carbonate group, an alkyl carboxylate group, a tosylate group, or a mesylate group; NR is an alkyl amide group or an alkyl amino group; and x ranges from 2 to 1,000.

13. The method of claim 11, wherein the second crosslinking agent is selected from one or more of the group comprising A-(OH) x , A-(OR’) x , A-(C=C) x , and A-(C≡C) x .​​​​ wherein A is a monomer, a multimer, or a second polymer having a molecular weight ranging from 100 to 20,000; R’ is an alkoxy group, an alkenyl group, or an alkynyl group; and x ranges from 2 to 1,000.

14. The method of claim 11, wherein the intermediate layer comprises at least one material selected from the group consisting of silicon-containing materials including inorganic polymers, siloxane polymers, silicon oxide, silicon nitride, silicon oxynitride, polysilicon, and metal-containing organic polymeric materials.

15. The method of claim 11, further comprising: selectively exposing the photoresist layer to actinic radiation; developing the selectively exposed photoresist layer to form a photoresist pattern; extending the photoresist pattern into the intermediate layer and the bottom layer to expose the substrate; etching the substrate; and removing the photoresist layer, the intermediate layer, and the bottom layer.

16. A spin-on carbon composition, characterized by, comprises: a carbon backbone polymer; a first crosslinking agent; and a second crosslinking agent, wherein the first crosslinking agent reacts with the carbon backbone polymer at a first temperature to partially crosslink into a first polymer, and the second crosslinking agent reacts with the first polymer at a second temperature higher than the first temperature to further crosslink the carbon backbone polymer.

17. The spin-on carbon composition of claim 16, wherein the first crosslinker is selected from one or more of the group comprising A-(OR) x , A-(NR) x , and . wherein A is a monomer, multimer, or polymer having a molecular weight ranging from 100 to 20,000; R is a hydrocarbyl, cycloalkyl, cycloalkyl epoxy, or C3-C15 heterocyclyl; OR is an alkoxy, cycloalkoxy, carbonate, alkyl carbonate, alkyl carboxylate, tosylate, or mesylate; NR is an alkyl amide or alkyl amino; and x ranges from 2 to 1,000.

18. The spin-coated carbon composite of claim 16, wherein the second crosslinking agent is selected from A-(OH)₂. x A-(OR') x A-(C=C) x and A-(C≡C) x One or more groups, wherein A is a monomer, multimer, or polymer having a molecular weight ranging from 100 to 20,000; R' is an alkoxy, alkenyl, or alkynyl; and x ranges from 2 to 1,000.

19. The spin-on carbon composition of claim 16, wherein the concentration of the first crosslinking agent and the second crosslinking agent in the spin-on carbon composition ranges from 20 wt.% to 50 wt.% of the total weight of the first crosslinking agent and the second crosslinking agent and the first polymer.

20. The spin-on carbon composition of claim 16, wherein the spin-on carbon composition further comprises a solvent.

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