This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2015-0182672, filed on Dec. 21, 2015, in the Korean Intellectual Property Office (KIPO), the content of which is incorporated by reference herein in its entirety.
The present invention generally relates to photoresist compositions, methods of forming patterns and methods of manufacturing semiconductor devices, and more particularly, to photoresist compositions including a photosensitive resin, and methods of forming patterns and methods of manufacturing semiconductor devices using the photoresist compositions.
A photolithography process may be utilized for forming various patterns included in a semiconductor device. For example, a photoresist layer may be exposed to an actinic radiation or particle beams to cause a chemical reaction in the exposed portion, and for a positive tone photoresist, the exposed portion may then be selectively removed by a developer solution to form a photoresist pattern. For a negative tone photoresist, the unexposed portion may be selectively removed by the developer solution to form a photoresist pattern. An underlying layer for manufacturing semiconductor devices may be patterned using the photoresist pattern as an etching mask to form a desired pattern.
Resolution of the photolithography process may be affected by properties of a light source used in the exposure process, chemical components in a photoresist composition, etc.
Example embodiments provide a photoresist composition having an enhanced resolution, a method of forming a pattern using a photoresist composition having an enhanced resolution, and a method of manufacturing a semiconductor device using a photoresist composition having an enhanced resolution.
According to an example embodiment of the present inventive concept, there is provided a photoresist composition that may include a photosensitive resin including a blend of a photoresist polymer and a dye resin, an amount of the dye resin being in a range from about 20 weight percent to about 80 weight percent based on a total weight of the photosensitive resin, a photo-acid generator, and a solvent.
According to an example embodiment of the present inventive concept, there is provided a photoresist composition that may include a photosensitive resin including a photoresist polymer integrally combined with a novolac unit, a photo-acid generator, and a solvent.
According to an example embodiment of the present inventive concept, there is provided a method of forming a pattern. In the method, a photoresist composition may be prepared. The photoresist composition may include a blend of a photoresist polymer and a dye resin, or a photoresist polymer integrally combined with a dye unit. The photoresist composition may be coated directly on a metal layer to form a photoresist layer. An exposure process may be performed on the photoresist layer to form a photoresist pattern. The metal layer may be patterned using the photoresist pattern as an etching mask.
According to an example embodiment of the present inventive concept, there is provided a method of manufacturing a semiconductor device. In the method, memory cells may be formed on a substrate. An insulation layer may be formed on the substrate to cover the memory cells. Contacts electrically connected to the memory cells may be formed through the insulation layer. A metal layer may be formed on the contacts and the insulation layer. A photoresist composition may be coated directly on the metal layer to form a photoresist layer. The photoresist composition may include a blend of a photoresist polymer and a dye resin, or a photoresist polymer integrally combined with a dye unit. An exposure process may be performed on the photoresist layer to form a photoresist pattern. The metal layer may be etched using the photoresist pattern as an etching mask to form a conductive line electrically connected to at least one of the contacts.
According to an example embodiment of the present inventive concept, there is provided a method of forming a pattern. In the method, a substrate may be provided and the substrate may have a metal layer on top. A photoresist layer may be deposited directly on the metal layer. The photoresist layer may include a photoresist polymer which is a polyhydroxystyrene (PHS)-based polymer, a dye resin which is a novolac-based resin, a photo-acid generator which is an onium salt, and an acid quencher which is an amine or an oxide, in which an amount of the dye resin may be in a range from about 25 weight percent to about 75 weight percent based on a total weight of the photoresist polymer and the dye resin combined. The photoresist layer may be patternwise exposed through a photomask with a KrF excimer laser light to form an exposed photoresist layer. The exposed photoresist layer may be developed with an aqueous TMAH developer or an alcohol-based solvent to form a photoresist pattern. The metal layer may be etched using the photoresist pattern as an etching mask.
Example embodiments of the present inventive concept will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, and in which:
Since the drawings in
Various example embodiments of the present inventive concept will be described more fully hereinafter with reference to the accompanying drawings, in which some example embodiments are shown. The present inventive concept may, however, be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this description will be thorough and complete, and will fully convey the scope of the present inventive concept to those skilled in the art.
It will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on”, “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numerals refer to like elements throughout the specification. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that, although the terms “first”, “second”, “third”, “fourth” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section, or vice versa, without departing from the teachings of the present inventive concept.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be oriented differently (for example, rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein would then be interpreted accordingly.
The terminology used herein is for the purpose of describing particular example embodiments and is not intended to be limiting of the present inventive concept. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
A photoresist composition in accordance with an example embodiment of the present inventive concept may be utilized in a photo-lithography process for patterning a metal layer. For example, the photoresist composition may be utilized for forming a gate electrode and/or various wiring structures included in a semiconductor device.
In an example embodiment of the present inventive concept, the photoresist composition may include a photosensitive resin, a photo-acid generator (PAG) and a solvent. The photosensitive resin may include a blend of a dye resin and a photoresist polymer, or a photoresist polymer incorporated with a dye unit.
The photoresist polymer may include a polymer used in a positive-type photoresist composition. For example, the photoresist polymer may include a backbone chain of polystyrene, polyhydroxystyrene (PHS), polyacrylate, polymethacrylate, polyvinyl ester, polyvinyl ether, polyolefin, polynorbornene, polyester, polyamide, polycarbonate or the like.
In an example embodiment of the present inventive concept, a PHS-based polymer may be used as the photoresist polymer. In this case, the photoresist polymer may include a repeating unit represented by the following Chemical Formula 1.
In the Chemical Formula 1, R1 may represent hydrogen or a C1˜C6 alkyl group. R2 may be, e.g., hydrogen, a C1˜C6 alkyl group, a C3˜C6 cycloalkyl group or a C1˜C6 alkoxy group.
In an example embodiment of the present inventive concept, the photoresist polymer may include an acid-labile repeating unit. For example, the acid-labile repeating unit may include an acid-labile protecting group that may be separated by an acid (H+). For example, the acid-labile protecting group may include, for example, an acetal group, a ketal group, an ortho ester group, an ether group, a thioether group, a tertiary alkoxycarbonyl group, or a tertiary ester group.
In an example embodiment of the present inventive concept, the dye resin may be blended with the photoresist polymer. In an example embodiment of the present inventive concept, the dye resin may include a novolac-based resin. Novolac resins are phenol-formaldehyde resins, and can be produced by reacting a molar excess of phenol (usually methyl substituted) with formaldehyde in the presence of an acid-catalyst, such as oxalic acid, hydrochloric acid or sulfuric acid. The phenol units are mainly linked by methylene and/or ether groups. For example, the novolac-based resin may include a repeating unit represented by the following Chemical Formula 2.
In the Chemical Formula 2, for example, R3 may be independently hydrogen or a C1˜C6 alkyl group.
Chemical Formula 2 exhibits a linear repeating unit with methylene linkages between phenol units at the ortho positions. However, the novolac-based resin may be produced with one or more types of cresols, such as meta-cresol, ortho-cresol, and para-cresol, and may contain methylene linkages at ortho and/or para positions of the phenolic units in the novolac polymer. The novolac polymer may be a linear or a branched polymer.
The novolac-based resin may have a light-absorbent property. For example, the novolac resin may absorb deep UV light. The novolac-based resin may be blended with the photoresist polymer to serve as a dye. Thus, the photoresist polymer blended with the novolac-based resin may serve as a base component of a photoresist having a light-absorbent property.
In an example embodiment of the present inventive concept, an amount of the dye resin may be in a range from about 20 weight percent (wt %) to about 80 wt % based on a total weight of the photosensitive resin. If the amount of the dye resin is less than about 20 wt %, a light reflected from a metal layer by a diffused reflection may not be sufficiently absorbed by the photosensitive resin. If the amount of the dye resin exceeds about 80 wt %, the light-absorbent property may be excessively high, so as to degrade the resolution of a photolithography process.
In an example embodiment of the present inventive concept, the amount of the dye resin may be in a range from about 25 wt % to about 75 wt % based on the total weight of the photosensitive resin. In an example embodiment of the present inventive concept, the amount of the dye resin may be in a range from about 50 wt % to about 75 wt % based on the total weight of the photosensitive resin.
In an example embodiment of the present inventive concept, the dye unit may be integrally combined with the photoresist polymer to be used as the photosensitive resin.
In an example embodiment of the present inventive concept, the photoresist polymer may include a PHS-based polymer, and a novolac unit having a structure represented by, e.g., the Chemical Formula 2 above may be combined with the PHS-based polymer as the dye unit.
In an example embodiment of the present inventive concept, the novolac unit may be combined to at least one aryl ring included in the PHS-based polymer. For example, the novolac unit may be combined to the aryl ring through an ether bond. In this case, the photosensitive resin may include a repeating unit represented by, e.g., the following Chemical Formula 3.
In the Chemical Formula 3, RI, R2 and R3 may be substantially the same as those defined in the Chemical Formulae 1 and 2 above.
As indicated in Chemical Formula 3, the novolac unit may be combined with an aryl ring of the PHS-based polymer via a linker group designated as “X”. For example, X may include a C1˜C10, alkyl group, a C3˜C10 cycloalkyl group, a C1˜C10 ether group, a C3˜C16 diether group or a combination thereof.
In an example embodiment of the present inventive concept, the novolac unit may be combined with at least two aryl rings of the PHS-based polymer. In this case, the novolac unit may include at least two connection points for being combined to different aryl rings included in the PHS-based polymer.
In an example embodiment of the present inventive concept, the novolac unit may be combined with the photoresist polymer, and may serve as a leaving group that may be removed by an acid generated from the PAG during an exposure process.
The PAG may include any compounds capable of generating acids by the exposure process. For example, the PAG may include, but is not limited to, an onium salt, an aromatic diazonium salt, a sulfonium salt, a triarylsulfonium salt, a diarylsulfonium salt, a monoarylsulfonium salt, an iodonium salt, a diaryliodonium salt, nitrobenzyl ester, disulfone, diazo-disulfone, sulfonate, trichloromethyl triazine, N-hydroxysuccinimide triflate, or the like. These may be used alone or in a combination thereof.
The solvent may include an organic solvent having a good solubility for a polymer material, and a good coatability (e.g., good coating characteristics) for a formation of a uniform photoresist layer. Examples of the solvent may include cyclohexanone, cyclopentanone, 2-heptanone, tetrahydrofuran (THF), dimethylformamide, propylene glycol monomethyl ether acetate (PGMEA), ethyl 3-ethoxypropionate, n-butyl acetate, ethyl lactate, methyl ethyl ketone, benzene or toluene. These may be used alone or in a combination thereof.
In an example embodiment of the present inventive concept, the photoresist composition may further include an acid quencher. The acid quencher may prevent the acid generated from the PAG at an exposed portion of a photoresist layer from being excessively diffused. For example, the acid quencher may include tetra-alkylammonium hydroxide, secondary and tertiary amines, pyridinium derivatives and the like.
In an example embodiment of the present inventive concept, the photoresist composition may include an additive such as a sensitizer, a surfactant, etc.
The sensitizer may be added in the photoresist composition to facilitate a formation of the exposed portion by amplifying an amount of photons. Example of the sensitizer may include, but are not limited to, benzophenone, benzoyl, thiophene, naphthalene, anthracene, phenanthrene, pyrene, coumarin, thioxanthone, acetophenone, naphthoquinone, anthraquinone, or the like. These may be used alone or in a combination thereof.
The surfactant may be added in the photoresist composition to facilitate a coating of the photoresist composition. For example, the surfactant may include an ethyleneglycol-based compound.
In an example embodiment of the present inventive concept, the photoresist composition may include the photosensitive resin in a range from about 5 wt % to about 20 wt %, the PAG in a range from about 0.1 wt % to about 1 wt %, the acid quencher in a range from about 0.01 wt % to about 0.5 wt %, the additive in a range from about 0.01 wt % to about 1 wt %, and the solvent in a range from about 78 wt % to about 94 wt %.
As described above, the photoresist composition according to an example embodiment of the present inventive concept may include the photosensitive resin that may include the dye resin or the dye unit. Accordingly, a light from a metal layer by a diffused reflection may be effectively absorbed, and a desired photosensitive property may be maintained to obtain a better resolution of a photo-lithography process.
As described above, the photoresist composition may include, e.g., the novolac resin or the novolac unit having the light-absorbent property. The novolac resin or the novolac unit may be employed in an exposure process using, e.g., radiation generated from an I-line source. I-line source is a mercury vapor lamp and provides 365 nm light for photoresist exposure. The novolac resin or the novolac unit may be blended or combined with the PHS-based polymer, so that the photoresist composition may be also utilized in an exposure process using, e.g., a light generated from a KrF light source. KrF light source is a krypton-fluoride excimer laser and provides a KrF excimer laser light with 248 nm wavelength for photoresist exposure. Thus, a pattering process of the metal layer may be implemented with more enhanced resolution.
Referring to
An image may be transferred from a photoresist pattern to the object layer 110, so that the object layer 110 may be converted to a desired (or predetermined) pattern. In an example embodiment of the present inventive concept, the object layer 110 may be formed substantially as a metal layer. For example, the object layer 110 may be formed of a metal such as copper, tungsten, aluminum, cobalt, titanium, tantalum, or the like, by a sputtering process, an atomic layer deposition (ALD) process, a physical vapor deposition (PVD) process, a chemical Vapor Deposition (CVD) or a plating process.
Referring to
The photoresist composition according to an example embodiment of the present inventive concept as described above may be coated on the object layer 110 by, e.g., a spin coating process, a dip coating process, a spray coating process, or the like. In an example embodiment of the present inventive concept, the photoresist composition may be coated to form a preliminary photoresist layer, and the preliminary photoresist layer may be baked to remove the solvent by a soft-baking process to form the photoresist layer 120.
In an example embodiment of the present inventive concept, the photoresist layer 120 may be formed directly on a top surface of the object layer 110.
As described above, the photoresist composition may include a photosensitive resin, a PAG and a solvent. The photosensitive resin may include a blend of a dye resin and a photoresist polymer, or a photoresist polymer incorporated with a dye unit.
In an example embodiment of the present inventive concept, a PHS-based polymer including a repeating unit as represented by the Chemical Formula 1 above may be utilized as the photoresist polymer. The PHS-based polymer may include a styrene repeating unit and an acid-labile repeating unit containing an acid-labile protecting group.
In an example embodiment of the present inventive concept, a novolac-based resin including a repeating unit represented by the Chemical Formula 2 above may be used as the dye resin. The dye unit may include a novolac unit.
If the photosensitive resin includes a blend of the photoresist polymer and the dye resin, an amount of the dye resin may be in a range from about 20 wt % to about 80 wt % based on a total weight of the photosensitive resin.
If the photosensitive resin includes the photoresist polymer integrally incorporated with the dye unit, the novolac unit may be combined to at least one aryl ring included in the PHS-based polymer as represented by the Chemical Formula 3 above.
The photoresist composition may further include an acid quencher, and may further include an additive such as a sensitizer and/or a surfactant.
In an example embodiment of the present inventive concept, the photoresist composition may include the photosensitive resin in a range from about 5 wt % to about 20 wt %, the PAG in a range from about 0.1 wt % to about 1 wt %, the acid quencher in a range from about 0.01 wt % to about 0.5 wt %, the additive in a range from about 0.01 wt % to about 1 wt %, and the solvent in a range from about 78 wt % to about 94 wt %.
Referring to
In an example embodiment of the present inventive concept, as illustrated in
A light may be generated from a light source 140 toward the exposure mask, and the light through a portion of the transparent substrate 130 between the light-shielding portions 135 may be irradiated on the photoresist layer 120. The light source 140 may include a source of, e.g., ArF, KrF, an electron beam, I-line, extreme ultraviolet (EUV), etc. In an example embodiment of the present inventive concept, a KrF light source may be utilized as the light source.
A portion of the photoresist layer on which the light through the exposure mask may be irradiated may be transformed into the exposed portion 123. A remaining portion of the photoresist layer 120 except for the exposed portion 123 may be defined as the non-exposed portion 125.
An acid may be generated from the PAG at the exposed portion 123 so that the protecting group included in the photoresist polymer may be deprotected. A polar group or a hydrophilic group such as a hydroxyl group or a carboxyl group may be created at a site from which the protecting group is removed at the exposed portion 123. Thus, a solubility of the exposed portion 123 with respect to a developer solution, e.g., a hydrophilic solution, used in a subsequent developing process may be increased.
In an example embodiment of the present inventive concept, if the dye unit is incorporated with the photoresist polymer, a reaction may be induced at the exposed portion 123 according to, e.g., the following reaction mechanism.
[Before Exposure Process]
Before the exposure process, the novolac unit as the dye unit may be connected to an aryl ring of a PHS-based polymer (designated as a dotted quadrangle) via a linker group (designated as a dotted ellipse). As represented in the structural formula above, the novolac unit may be connected to a plurality of the aryl rings via a plurality of the linker groups, and may include a plurality of connection points.
[After Exposure Process]
An acid (H+) may be generated from the PAG by the exposure process, so that the connection points between the linker groups and the PHS-based polymer, and between the linker groups and the novolac unit may be separated. Hydroxyl groups may be created at the connection points, and thus polar and/or hydrophilic properties of the exposed portion 123 may increase.
As described with reference to the reaction mechanism, the dye unit may be combined to the photoresist polymer as a leaving group capable of being separated by the acid.
As illustrated in
According to an example embodiment of the present inventive concept, the light scattered from the object layer 110 by the diffused reflection may be absorbed by the photoresist layer 120, or the dye resin or the dye unit included therein. Additionally, the dye unit may serve as the leaving group separated by an acid to facilitate a formation of the exposed portion 123.
In a comparative example, an anti-reflective layer may be formed between the object layer 110 and the photoresist layer 120 for preventing the diffused reflection. The anti-reflective layer may be formed of an organic-based or inorganic-based material. If the object layer 110 includes a metal, an inorganic-based anti-reflective layer may be formed of, e.g., titanium nitride (TiN) for reducing a damage of the metal. In the comparative example, an additional layer deposition may be added to form the anti-reflective layer, and an etching process with respect to the anti-reflective layer may be also added before patterning the object layer 110. Further, a process for removing the anti-reflective layer after completing a photo-lithography process may be also needed.
According to the example embodiments of the present inventive concept described above, the photoresist layer 120 may include the dye resin or the dye unit, so that the photoresist layer 120 may have a light-absorbent property, and the anti-reflective layer may not be formed. Thus, better efficiency and higher productivity of a patterning process or a photo-lithography process may be obtained.
In an example embodiment of the present inventive concept, a post exposure baking (PEB) process may be further performed after the exposure process. The acid generated during the exposure process may be uniformly distributed throughout the exposed portion 123 by the PEB process. Most chemically amplified photoresists depend on the PEB process to drive the acid catalyzed deprotection reaction. For the photoresist systems having extremely acid labile groups, PEB step may not be needed, but the PEB process will enhance the deprotection reaction.
Referring to
An alcohol-based solution, or a hydroxide-based aqueous solution including, e.g., aqueous tetra methyl ammonium hydroxide (TMAH) solution may be used as a developer solution in the developing process. As described above, the exposed portion 123 may become more polar or hydrophilic than the non-exposed portion 125 through a photochemical reaction, and may become soluble to the developer solution. The more polar or hydrophilic property of the exposed portion renders the exposed portion more soluble in hydrophilic solution. Thus, only the exposed portion 123 may be removed by the developer solution such as aqueous TMAH solution.
Referring to
The etching process may include a dry etching process and/or a wet etching process properly selected in consideration of an etching selectivity between the photoresist pattern and the metal. For example, the etching process may include the wet etching process using an etchant solution such as a peroxide-based solution.
Referring to
In an example embodiment of the present inventive concept, the photoresist pattern may be removed by an aching process and/or a strip process. The target pattern 115 may serve as a conductive pattern of a semiconductor device, e.g., a wiring, a contact, a plug, a pad, etc.
As described with reference to
Referring to
A first photoresist layer 120a and a second photoresist layer 120b may be sequentially formed on the object layer 110.
The first photoresist layer 120a may serve as an underlayer for improving an adhesion between the object layer 110 and the second photoresist layer 120b. In an example embodiment of the present inventive concept, the first photoresist layer 120a may include a polymer having a backbone structure substantially the same as or similar to that of the second photoresist layer 120b, and may further include an adhesion unit or a wetting unit. The adhesion unit or a wetting unit may include, e.g., an ester group, a ketone group and/or a lactone group. In an example embodiment of the present inventive concept, the first photoresist layer 120a may be formed directly on a top surface of the object layer 110. The first photoresist layer 120a may or may not include a PAG.
The second photoresist layer 120b may have a composition or a construction substantially the same as that of the photoresist layer 120 of
In an example embodiment of the present inventive concept, the dye resin or the dye unit may be also included in the first photoresist layer 120a.
Referring to
In an example embodiment of the present inventive concept, the second photoresist layer 120b may be divided into a second exposed portion and a second non-exposed portion 125b by an exposure process. In an example embodiment of the present inventive concept, an acid generated from a PAG at the second exposed portion may be diffused into a portion of the first photoresist layer 120a under the second exposed portion. Accordingly, the first photoresist layer 120a may be divided into a first exposed portion and a first non-exposed portion 125a.
The second and first exposed portions may be removed by a developing process. A photoresist pattern including the first non-exposed portion 125a and the second non-exposed portion 125b may be formed on the object layer 110.
Referring to
In
Referring to
In an example embodiment of the present inventive concept, a contact hole may be formed in the lower insulation layer 210, and an ion-implantation process may be performed through the contact hole to form an impurity region 203 at an upper portion of the substrate 200. The contact hole may be filled with a first conductive layer by a deposition process or a plating process to form the lower contact 215. The lower contact 215 may be electrically connected to the impurity region 203.
The lower insulation layer 210 may be formed of, e.g. silicon oxide or silicon oxynitride. For example, the lower insulation layer 210 may be formed of, e.g., plasma enhanced oxide (PEOX), tetraethyl orthosilicate (TEOS), phospho silicate glass (PSG), borosilicate glass (BSG), etc.
Referring to
The first and second etch-stop layers 220 and 230 may be formed of, e.g., silicon nitride or silicon oxynitride. The insulating interlayer 225 may be formed of silicon oxide, or a low dielectric (low-k) oxide such as, e.g., polysiloxane or silsesquioxane. The first etch-stop layer 220, the insulating interlayer 225 and a second etch-stop layer 230 may be formed by, e.g., a CVD process, an ion-beam sputtering process, a spin coating process, etc.
The hard mask 235 may be formed of a silicon-based or carbon-based spin-on hard mask (SOH) material. A top surface of the second etch-stop layer 230 may be partially exposed through the hard mask 235.
Referring to
In an example embodiment of the present inventive concept, a top surface of the lower contact 215 may be exposed through the opening 240. For example, the opening 240 may have a contact hole shape through which each lower contact 215 may be exposed. In an example embodiment of the present inventive concept, the opening 240 may have a linear shape extending in the second direction through which a plurality of the lower contacts 215 may be exposed. A plurality of the openings 240 may be formed along the first direction.
The hard mask 235 may be removed by, e.g., an ashing process after forming the openings 240.
Referring to
In an example embodiment of the present inventive concept, a second conductive layer filling the openings 240 may be formed on the second etch-stop layer 230. An upper portion of the second conductive layer may be planarized by a chemical mechanical polishing/planarization (CMP) process until a top surface of the insulating interlayer 225 is exposed to form the conductive patterns 245. The second conductive layer may be formed of a metal such as, e.g., copper, aluminum, tungsten, or the like, by a sputtering process or an ALD process.
In an example embodiment of the present inventive concept, a barrier conductive layer may be formed on an inner wall of the opening 240 before forming the second conductive layer. The barrier conductive layer may be formed of a metal nitride such as, e.g., titanium nitride or tantalum nitride.
In an example embodiment of the present inventive concept, the second conductive layer may be formed by a plating process. For example, a seed layer may be formed conformally on the barrier conductive layer by a sputtering process using a copper target. Subsequently, an electroplating process may be performed so that the second conductive layer including copper may be grown or precipitated on the seed layer to fill the openings 240.
Referring to
In an example embodiment of the present inventive concept, the third conductive layer 250 may be formed of a metal such as, e.g., copper, aluminum, tungsten, or the like, by a sputtering process or an ALD process.
The photoresist layer 260 may be formed from a process and a photoresist composition substantially the same as or similar to those described with reference to
As described above, the photoresist composition may include a photosensitive resin, a PAG and a solvent. The photosensitive resin may include a blend of a dye resin and a photoresist polymer, or a photoresist polymer incorporated with a dye unit.
In an example embodiment of the present inventive concept, a PHS-based polymer including a repeating unit as represented by the Chemical Formula 1 above may be utilized as the photoresist polymer. The PHS-based polymer may include a styrene repeating unit and an acid-labile repeating unit including an acid-labile protecting group.
In an example embodiment of the present inventive concept, a novolac-based resin including a repeating unit represented by the Chemical Formula 2 above may be used as the dye resin. The dye unit may include a novolac unit.
If the photosensitive resin includes a blend of the photoresist polymer and the dye resin, an amount of the dye resin may be in a range from about 20 wt % to about 80 wt % based on a total weight of the photosensitive resin.
If the photosensitive resin includes the photoresist polymer integrally incorporated with the dye unit, the novolac unit may be combined to at least one aryl ring included in the PHS-based polymer as represented by the Chemical Formula 3 above.
The photoresist composition may further include an acid quencher, and may further include an additive such as a sensitizer and/or a surfactant.
In an example embodiment of the present inventive concept, the photoresist composition may include the photosensitive resin in a range from about 5 wt % to about 20 wt %, the PAG in a range from about 0.1 wt % to about 1 wt %, the acid quencher in a range from about 0.01 wt % to about 0.5 wt %, the additive in a range from about 0.01 wt % to about 1 wt %, and the solvent in a range from about 78 wt % to about 94 wt %.
Referring to
While performing the exposure process, a diffusively reflected light may be absorbed by the dye resin or the dye unit included in the photosensitive resin so that the photoresist patterns 265 may achieve high resolution.
Referring to
The wiring 255 may extend in, e.g., the second direction, and may be electrically connected to a plurality of the conductive patterns 245.
As described above, the wiring of a fine pitch or a fine line width included in a semiconductor device may be formed using the photoresist composition according to an example embodiment of the present inventive concept with a high resolution.
Specifically,
Referring to
The substrate 300 may include, e.g., a silicon substrate, a germanium substrate, a silicon-germanium substrate, an SOI substrate, a GOI substrate, etc. The substrate 300 may include a group III-V compound, such as, e.g., InP, GaP, GaAs, GaSb, or the like.
The tunnel insulation layer 310 may be formed of, e.g., silicon oxide, silicon nitride and/or silicon oxynitride. In an example embodiment of the present inventive concept, the tunnel insulation layer 310 may be formed as a multi-layered structure, such as, e.g., an oxide-nitride-oxide (ONO)-layered structure or an oxide-silicon-oxide (OSO)-layered structure.
The charge storage layer 320 may be formed by a deposition process using a silicon precursor, and p-type or n-type impurities. The charge storage layer 320 may be formed of doped polysilicon. For example, the charge storage layer 320 may serve as a floating gate layer.
In an example embodiment of the present inventive concept, as illustrated in
Subsequently, the dielectric layer 330, the first control gate layer 340, the second control gate layer 345 and the gate mask layer 350 may be sequentially formed on the charge storage layer 320 and the isolation layer 305.
The dielectric layer 330 may be formed as a single-layered structure of an oxide layer or a nitride layer, or a multi-layered structure, such as an ONO-layered structure. In an example embodiment of the present inventive concept, the dielectric layer 330 may be formed of a high-k metal oxide. The dielectric layer 330 may have a substantially wavy profile along surfaces of the charge storage layer 320, the tunnel insulation layer 310 and the isolation layer 305.
The first control gate layer 340 may fill remaining portions of the isolation trench on the dielectric layer 330. In an example embodiment of the present inventive concept, the first control gate layer 340 may be formed of doped polysilicon. The second control gate layer 345 may be formed of a metal or a metal silicide. The gate mask layer 350 may be formed of silicon nitride or silicon oxynitride.
The tunnel insulation layer 310, the charge storage layer 320, the dielectric layer 330, the first control gate layer 340, the second control gate layer 345 and the gate mask layer 350 may be formed by, e.g., at least one of a CVD process, a plasma enhanced chemical vapor deposition (PECVD) process, a sputtering process, a physical vapor deposition (PVD) process and an ALD process.
Referring to
A portion of each gate structure, for example, the dielectric pattern 335, the first control gate 343, the second control gate 347 and the gate mask 355 may have linear shapes continuously extending substantially in the second direction. The charge storage pattern 325 and the tunnel insulation pattern 315 may have island shapes spaced apart from each other along the first and second directions. In an example embodiment of the present inventive concept, the tunnel insulation layer 310 may not be completely removed between the gate structures neighboring each other by the above etching process. In this case, the tunnel insulation pattern 315 may have a linear shape extending in the first direction.
A central portion of the substrate 300 may correspond to a cell region. The gate structures may be formed on the cell region by relatively narrow width and pitch, and may serve as memory cells.
Peripheral portions of the substrate 300 adjacent to the cell region may correspond to a selection region. The gate structures may be formed on the selection region by relatively large width and pitch.
In an example embodiment of the present inventive concept, the charge storage pattern 325 and the first control gate 343 of the gate structure formed on the selection region may be electrically connected to or in contact with each other. In this case, portions of the charge storage layer 320 and the first control gate layer 340 on the selection region may be connected to each other by a butting process during a process illustrated with reference to
Referring to
In an example embodiment of the present inventive concept, an upper portion of the substrate 300 may be exposed between the gate spacers 357 formed on the cell region and the selection region, because a distance between the gate structures on the cell region and the selection region may be relatively large. Impurities may be provided in the upper portion of the substrate 300 by an ion-implantation process to form first and second impurity regions 303 and 307. For example, the first and second impurity regions 303 and 307 may extend linearly in the second direction.
A first insulating interlayer 360 covering the gate structures and the gate spacers 357 may be formed. The first insulating interlayer 360 may be formed of silicon oxide, such as, e.g., PEOX-based, TEOS-based or silicate glass-based materials.
A first plug 365 may be formed through the first insulating interlayer 360 to be in contact with or electrically connected to the first impurity region 303. For example, the first insulating interlayer 360 may be partially etched to form a first contact hole exposing the first impurity region 303. A first conductive layer filling the first contact hole may be formed on the first insulating interlayer 360, and an upper portion of the first conductive layer may be planarized by, e.g., a CMP process to form the first plug 365. The first plug 365 may serve as a common source line (CSL) contact of the semiconductor device.
In an example embodiment of the present inventive concept, a CSL electrically connected to the first plug 365 may be further formed on the first insulating interlayer 360.
Referring to
Referring to
In an example embodiment of the present inventive concept, the third conductive layer 380 may be formed of a metal such as, e.g., copper, tungsten, aluminum by a sputtering process or an ALD process.
The photoresist layer 390 may be formed from a process and a photoresist composition substantially the same as or similar to those described with reference to
As described above, the photoresist composition may include a photosensitive resin, a PAG and a solvent. The photosensitive resin may include a blend of a dye resin and a photoresist polymer, or a photoresist polymer incorporated with a dye unit.
In an example embodiment of the present inventive concept, a PHS-based polymer including a repeating unit as represented by the Chemical Formula 1 above may be utilized as the photoresist polymer. The PHS-based polymer may include a styrene repeating unit and an acid-labile repeating unit containing an acid-labile protecting group.
In an example embodiment of the present inventive concept, a novolac-based resin including a repeating unit represented by the Chemical Formula 2 above may be used as the dye resin. The dye unit may include a novolac unit.
If the photosensitive resin includes a blend of the photoresist polymer and the dye resin, an amount of the dye resin may be in a range from about 20 wt % to about 80 wt % based on a total weight of the photosensitive resin.
If the photosensitive resin includes the photoresist polymer integrally incorporated with the dye unit, the novolac unit may be combined to at least one aryl ring included in the PHS-based polymer as represented by the Chemical Formula 3 above.
The photoresist composition may further include an acid quencher, and may further include an additive such as a sensitizer and/or a surfactant.
In an example embodiment of the present inventive concept, the photoresist composition may include the photosensitive resin in a range from about 5 wt % to about 20 wt %, the PAG in a range from about 0.1 wt % to about 1 wt %, the acid quencher in a range from about 0.01 wt % to about 0.5 wt %, the additive in a range from about 0.01 wt % to about 1 wt %, and the solvent in a range from about 78 wt % to about 94 wt %.
Referring to
While performing the exposure process, a diffusively reflected light may be absorbed by the dye resin or the dye unit included in the photosensitive resin so that the photoresist patterns 395 may achieve high resolution.
Referring to
The conductive line 385 may extend in, e.g., the first direction, and a plurality of the conductive lines 385 may be formed along the second direction. For example, the conductive line 385 may serve as a bit line of the semiconductor device.
In an example embodiment of the present inventive concept, wirings electrically connected to the second control gate 347 and/or the first control gate 343 of the gate structure may be further formed. The wirings may be also formed by a photo-lithography process using the photoresist composition according to an example embodiment of the present inventive concept, and using a metal layer as an object layer.
In
Referring to
The substrate 400 may include a cell region C, an extension region E and a peripheral region P. The gate lines 430 and the insulating interlayer patterns 415 may be stacked throughout the cell region C and the extension region E as a stepped shape or a pyramidal shape.
A vertical channel structure may be formed through the gate lines 430 and the insulating interlayer patterns 415 on the cell region C of the substrate 400. The vertical channel structure may include a semiconductor pattern 410 contacting the top surface of the substrate 400, and a dielectric layer structure 440, a channel 442 and a filling insulation pattern 444 formed on the semiconductor pattern 410. The vertical channel structure may further include a pad 448 at an upper portion thereof.
The gate line 430 may surround outer sidewalls of the dielectric layer structures 440 included in a plurality of vertical channel structures, and may extend in the second direction.
A gate structure 408 including a gate insulation pattern 402, a gate electrode 404 and a gate mask 406 may be formed on the peripheral region P of the substrate 400. An impurity region 403 may be formed at an upper portion of the substrate 400 adjacent to the gate structure 408. A peripheral circuit transistor may be defined by the gate structure 408 and the impurity region 403, and a peripheral circuit protection layer 409 covering the peripheral circuit transistor may be formed on the peripheral region P.
A mold protection layer 420 may be formed on the substrate 400 to cover the peripheral circuit protection layer 409, and a lateral portion of a stack structure including the insulating interlayer patterns 415 and the gate lines 430. A first upper insulation layer 450 covering an uppermost insulating interlayer pattern 415g and the pads 448 may be formed on the mold protection layer 420.
In an example embodiment of the present inventive concept, a cutting pattern may be formed through the first upper insulation layer 450, the stack structure and the mold protection layer 420 in the first direction.
A second upper insulation layer 460 may be formed on the first upper insulation layer 450 and the cutting pattern. Subsequently, contacts extending through the second upper insulation layer 460, the first upper insulation layer 450, the insulating interlayer pattern 415 and/or the mold protection layer 420 may be formed.
In an example embodiment of the present inventive concept, a first contact 474 electrically connected to the pad 448 may be formed through the second and first upper insulation layers 460 and 450. For example, the first contact 474 may serve as a bit line contact.
Second contacts 472 eclectically connected to the gate line 430 at each level may be formed through the second upper insulation layer 460, the first upper insulation layer 450, the insulating interlayer pattern 415 and the mold protection layer 420 on the extension region E. A third contact 476 electrically connected to the impurity region 403 may be formed through the second upper insulation layer 460, the first upper insulation layer 450, the mold protection layer 420 and the peripheral circuit protection layer 409 on the peripheral region P.
Wirings electrically connected to the contacts may be formed on the second upper insulation layer 460. For example, a metal layer may be formed on the second upper insulation layer 460, and a photoresist layer may be formed on the metal layer.
The photoresist layer may be formed from a process and a photoresist composition substantially the same as or similar to those described with reference to
While performing the exposure process, a diffusively reflected light may be absorbed by a dye resin or a dye unit included in a photosensitive resin of the photoresist layer so that the photoresist pattern may achieve high resolution.
The metal layer may be partially etched using the photoresist pattern as an etching mask to form the wirings.
In an example embodiment of the present inventive concept, a first wiring 482 electrically connected to the first contact 474 may be formed on the cell region C. The first wiring 482 may extend in, e.g., the third direction, and may serve as a bit line.
A second wiring 480 electrically connected to the gate line 430 at each level via the second contact 472 may be formed on the extension region E. The second wiring 480 may serve as a signal wiring supplying a predetermined voltage to the gate line 430 at each level. The second wiring 480 may also extend on the peripheral region P to be electrically connected to the third contact 476.
As described above, in fabricating the planar-type or the 3-dimensional type non-volatile memory device, a photo-lithography process may be implemented using the photoresist composition according to an example embodiment of the present invention. Thus, a wiring having a fine pitch and a fine dimension may be achieved while preventing a reduction of resolution due to a diffusively reflected light.
Hereinafter, properties of a photoresist composition according to an example embodiment of the present inventive concept will be described in more detail with reference to
A photoresist composition was coated on an aluminum substrate having a thickness of 5,500 Å, and was baked to form a photoresist layer having a thickness of 0.8 μm. The photoresist composition included a blend of a commercially available PHS resin and a novolac resin. A diazonium salt was used as a PAG
An exposure process was performed using the light generated from a KrF light source, and a PEB process was performed at 110° C. for 50 seconds. The exposed photoresist layer was immersed in a 0.261N TMAH aqueous developer solution (2.38%) to remove an exposed portion, and a photoresist pattern was obtained.
The above procedure was repeated with different contents (wt %) of the PHS resin and the novolac resin in the blend (as listed in Table 1 below), and a surface profile of each photoresist pattern was observed.
In Comparative Example devoid of a dye resin (novolac resin) in the photoresist composition, the photoresist pattern had irregular pitch and line width due to a reduced resolution by a diffused reflection.
Referring to
According to an example embodiment of the present inventive concept, the photoresist composition may include a photosensitive resin in which a dye agent may be incorporated or blended. The photoresist composition may be directly coated on a metal layer. A diffusively reflected light from the metal layer may be absorbed by the dye agent during an exposure process. Thus, a reduction of the resolution may be effectively avoided even though an anti-reflective layer may not be formed on the metal layer.
The foregoing is illustrative of example embodiments of the present inventive concept and is not to be construed as limiting thereof. Although a few example embodiments of the present inventive concept have been described, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the novel teachings of the present inventive concept. Accordingly, all such modifications are intended to be included within the scope of the present inventive concept as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of various example embodiments of the present inventive concept and is not to be construed as limited to the specific example embodiments disclosed, and that modifications to the disclosed example embodiments, as well as other example embodiments, are intended to be included within the scope of the appended claims.
Number | Date | Country | Kind |
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10-2015-0182672 | Dec 2015 | KR | national |