Ultraviolet photoresist, method for patterning ultraviolet photoresist and use

Abstract

This invention relates to the field of photoresist technology, specifically to an ultraviolet (UV) photoresist, a method for patterning UV photoresist, and its applications. The UV photoresist comprises an organic solvent, a photosensitizer, and zirconium oxide nanoclusters, wherein the general chemical formula of the zirconium oxide nanoclusters is Zr. x O y (OH) z L m Where 2≤x≤20, 2≤y≤40, 0≤z≤40, 4≤m≤40, and L is an organic ligand containing a carboxyl group; the photosensitizer has the following structure: where R 1 * indicates a connection site; R 2 and R 3 Each occurrence is independently selected from -F, -Cl, -Br, or -I. The selection of photosensitizers in this invention can significantly reduce exposure dose and increase lithography speed, and has important application value.

Description

Technical Field

[0001] This invention relates to the field of photoresist technology, and more specifically, to an ultraviolet photoresist, a method for patterning ultraviolet photoresist, and its applications. Background Technology

[0002] Currently, ultra-large-scale integrated circuits (ULSIs) in the semiconductor industry are all manufactured using photolithography technology. The resolution and linewidth of photolithography directly determine the integration density, yield, and cost of integrated circuits. Photolithography is a micro-nano fabrication technology that utilizes the change in solubility of photoresist under an exposure beam to transfer patterns from a photomask to an exposure substrate. Photoresist is a type of mixed material sensitive to light or radiation. Currently, ultraviolet photoresist mainly consists of film-forming resin, photosensitizer, solvent, and other additives, with the film-forming resin being the main component.

[0003] Currently commercially available ultraviolet photoresists are photosensitive materials that are mainly based on polymer compounds as film-forming resins. They require a large exposure dose and have low sensitivity during use. Summary of the Invention

[0004] Based on this, the present invention provides a UV photoresist with low exposure dose and high sensitivity, a method for UV photoresist patterning, and its applications.

[0005] In one aspect, this invention provides an ultraviolet photoresist comprising an organic solvent, a photosensitizer, and zirconium oxide nanoclusters, wherein the general chemical formula of the zirconium oxide nanoclusters is Zr. x O y (OH) z L m , where 2≤x≤20, 2≤y≤40, 0≤z≤40, 4≤m≤40, and L is an organic ligand containing a carboxyl group;

[0006] The photosensitizer has the following structure:

[0007]

[0008] Among them, the ultraviolet photoresist described above, R 1 for: * indicates a connection point.

[0009] R 2 and R 3 Each occurrence is independently selected from -F, -Cl, -Br, or -I.

[0010] Optionally, as described above, the ultraviolet photoresist, R 2 and R 3 All are -Cl.

[0011] Optionally, the ultraviolet photoresist described above may contain at least one of the following: an acrylic acid ligand, a methacrylic acid ligand, a 1-hydroxy-2-naphthoic acid ligand, and a salicylic acid ligand.

[0012] Optionally, in the ultraviolet photoresist described above, the mass percentage of zirconium oxide nanoclusters in the organic solvent is 0.5% to 15%, and the mass percentage of photosensitizer is 0.001% to 1%.

[0013] Optionally, the organic solvent in the ultraviolet photoresist described above includes at least one of ethyl lactate, anisole, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, and isopropanol.

[0014] In another aspect, the present invention also provides a method for ultraviolet photoresist patterning, comprising the following steps:

[0015] The ultraviolet photoresist described above is spin-coated onto the substrate and then dried to form an ultraviolet photoresist film;

[0016] The ultraviolet photoresist film is exposed to ultraviolet light under a photomask and then developed in a developer to form a photolithographic pattern.

[0017] Optionally, the developer includes at least one selected from toluene, xylene, 1,2-diacetoxypropane, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, isopropanol, isobutanol, isoamyl alcohol, 4-methyl-2-pentanol, isopropoxyethanol, 1-methoxy-2-propanol, 1-propoxy-2-propanol, 1-butoxy-2-propanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, propylene glycol ethyl ether, 2-heptanone, and 2-butanone.

[0018] Optionally, in the ultraviolet photoresist patterning method described above, the light source for ultraviolet lithography exposure is ultraviolet light with a wavelength of 365 nm, deep ultraviolet light with a wavelength of 254 nm, or extreme ultraviolet light with a wavelength of 13.5 nm. Further, when the light source for ultraviolet lithography exposure is deep ultraviolet light with a wavelength of 254 nm, the exposure dose is greater than or equal to 7 mJ / cm². -2 When the light source for ultraviolet lithography is 365nm wavelength ultraviolet light, the exposure dose is greater than or equal to 300mJ / cm². -2 .

[0019] Optionally, the ultraviolet photoresist described above can also be used as an electron beam photoresist.

[0020] The ultraviolet photoresist of this invention uses zirconia nanoclusters as the film-forming resin, with a single nanocluster size of only 1nm-5nm, far smaller than the size of polymer chains (generally greater than 20nm). Therefore, compared with traditional polymer resin-based photoresists, the ultraviolet photoresist of this invention has the potential to etch patterns with smaller linewidths. After effective matching of the zirconia nanocluster film-forming resin with the photosensitizer, the sensitivity of the ultraviolet photoresist is significantly improved, the exposure dose is significantly reduced, and the photolithography efficiency is greatly enhanced. Furthermore, the presence of metal oxides gives the photoresist excellent mechanical properties and etching resistance, and the exposed pattern hardly undergoes deformation or peeling in the subsequent development process, resulting in high pattern fidelity. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1A and Figure 1B The exposure pattern obtained with an exposure wavelength of 254nm in Embodiment 1 of the present invention;

[0023] Figure 2A and Figure 2B The exposure pattern obtained with an exposure wavelength of 365nm in Embodiment 1 of the present invention;

[0024] Figure 3 The exposure pattern obtained by electron beam lithography in Embodiment 2 of the present invention;

[0025] Figure 4A and Figure 4B This is the exposure pattern obtained with an exposure wavelength of 254nm in the comparative example of this invention;

[0026] Figure 5A and Figure 5B This is the exposure pattern obtained with an exposure wavelength of 365nm in the comparative example of this invention. Detailed Implementation

[0027] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0028] Therefore, this invention is intended to cover such modifications and variations falling within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the invention are disclosed in or will be apparent from the following detailed description. It will be understood by those skilled in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof as used herein are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises the listed elements is not necessarily limited to those elements but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0030] Unless otherwise shown or indicated in the operational embodiments, all figures used to represent the amounts, physicochemical properties, etc., of ingredients in the specification and claims are to be understood to be adjusted by the term "about" in all cases. For example, therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired characteristics by utilizing the teachings disclosed herein. The use of numerical ranges indicated by endpoints includes all numbers within that range and any range within that range; for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0031] Photoresist "sensitivity" refers to the minimum light energy or minimum charge (for electron beam photoresist) incident per unit area that causes the photoresist to react completely. In this invention, the unit for ultraviolet photoresist sensitivity is mJ / cm². -2 (The smaller the value, the higher the photoresist sensitivity); the unit for electron beam photoresist sensitivity is μC / cm. -2 This indicates (the smaller the value, the higher the photoresist sensitivity). Photoresist sensitivity can also be reflected by the minimum exposure dose, where exposure dose = light intensity × exposure time.

[0032] In one aspect, this invention provides an ultraviolet photoresist comprising an organic solvent, a photosensitizer, and zirconium oxide nanoclusters, wherein the general chemical formula of the zirconium oxide nanoclusters is Zr. x O y (OH)z L m , where 2≤x≤20, 2≤y≤40, 0≤z≤40, 4≤m≤40, and L is an organic ligand containing a carboxyl group;

[0033] The photosensitizer has the following structure:

[0034]

[0035] Among them, R 1 for: * indicates a connection point;

[0036] R 2 and R 3 Each can be independently selected from -F, -Cl, -Br, or -I;

[0037] The photosensitizer in the ultraviolet photoresist has a high photolysis acid production efficiency. The acid produced by photolysis can quickly trigger a chemical reaction in the zirconium oxide nanoclusters, making the ultraviolet photoresist highly sensitive and thus reducing the exposure dose.

[0038] The ultraviolet photoresist of this invention uses zirconia nanoclusters as the film-forming resin, with a single nanocluster size of only 1nm-5nm, far smaller than the size of polymer chains (generally greater than 20nm). Therefore, compared with traditional polymer resin-based photoresists, the ultraviolet photoresist of this invention has the potential to etch patterns with smaller linewidths. After effective matching of the zirconia nanocluster film-forming resin with the photosensitizer, the sensitivity of the ultraviolet photoresist is significantly improved, the exposure dose is significantly reduced, and the photolithography efficiency is greatly enhanced. Furthermore, the presence of metal oxides gives the photoresist excellent mechanical properties and etching resistance, and the exposed pattern hardly undergoes deformation or peeling in the subsequent development process, resulting in high pattern fidelity.

[0039] In some implementations, R 2 and R 3 All are -Cl.

[0040] In some embodiments, the organic ligands containing carboxyl groups include, but are not limited to, acrylic acid ligands, methacrylic acid ligands, 1-hydroxy-2-naphthoic acid ligands, salicylic acid ligands, etc.

[0041] In some embodiments, the mass percentage of zirconium oxide nanoclusters in the organic solvent can be 0.5% to 15%, and can also be 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 14.5%, etc.

[0042] In some embodiments, the photosensitizer in the organic solvent can be 0.001% to 1% by mass, or it can be 0.002%, 0.003%, 0.005%, 0.006%, 0.008%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.3%, 0.5%, 0.8%, etc.

[0043] In some embodiments, the organic solvent is selected from those with strong solubility for the photosensitizer and zirconia nanoclusters, so that the photosensitizer and zirconia nanoclusters can be well dissolved and uniformly dispersed in the organic solvent. After spin-coating the UV photoresist onto the substrate and drying it to form a UV photoresist film, it can be ensured that the photosensitizer and zirconia nanoclusters can be uniformly dispersed in the UV photoresist film. After photolithography exposure, the exposed areas of the UV photoresist are difficult to dissolve in the developer, while the non-exposed areas of the UV photoresist can dissolve accurately and quickly. Preferably, any organic solvent commonly used in the art is acceptable, including but not limited to ethyl lactate, anisole, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, and isopropanol.

[0044] In another aspect, the present invention also provides a method for ultraviolet photoresist patterning, comprising the following steps:

[0045] The ultraviolet photoresist described above is spin-coated onto the substrate and then dried to form an ultraviolet photoresist film;

[0046] The ultraviolet photoresist film is exposed to ultraviolet light under a photomask and then developed in a developer to form a photolithographic pattern.

[0047] In some embodiments, the developer includes, but is not limited to, at least one of toluene, xylene, 1,2-diacetoxypropane, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, isopropanol, isobutanol, isoamyl alcohol, 4-methyl-2-pentanol, isopropoxyethanol, 1-methoxy-2-propanol, 1-propoxy-2-propanol, 1-butoxy-2-propanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, propylene glycol ethyl ether, 2-heptanone, and 2-butanone.

[0048] In some embodiments, the light source for ultraviolet lithography exposure is deep ultraviolet light with a wavelength of 254 nm or ultraviolet light with a wavelength of 365 nm. When the light source for ultraviolet lithography exposure is deep ultraviolet light with a wavelength of 254 nm, the exposure dose can be greater than or equal to 7 mJ / cm². -2 When the light source for ultraviolet lithography is 365nm wavelength ultraviolet light, the exposure dose can be greater than or equal to 300mJ / cm². -2 .

[0049] In some embodiments, the aforementioned ultraviolet photoresist can also be used as an electron beam photoresist, where the exposure dose can be as low as 120 μC cm⁻¹ when using an electron beam as the light source for photolithography. -2 the following.

[0050] In some embodiments, the substrate can be any substrate material commonly used in the art, such as silicon wafers, quartz sheets, glass sheets, etc.

[0051] In some implementations, when forming a photolithography pattern, a mask needs to be applied to block the light in order to form an ultraviolet photolithography pattern with a preset shape.

[0052] The following detailed description, in conjunction with specific embodiments, further illustrates the ultraviolet photoresist, the method for patterning ultraviolet photoresist, and its applications of the present invention.

[0053] Example 1

[0054] Take 0.03 g of 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine and 0.75 g of zirconium oxide nanoclusters (Zr6O4(OH)4(CH2=CCH3COO)). 12 The UV photoresist solution was dissolved in 14.25 g of propylene glycol monomethyl ether acetate solvent and stirred until completely dissolved. The solution was then filtered twice through a 0.22 μm pore size filter membrane. After filtration, the UV photoresist solution was placed in a brown glass bottle and stored at room temperature away from light.

[0055] Take an appropriate amount of the prepared UV photoresist solution and drop it onto the surface of a clean silicon wafer. Place the substrate material into the wafer at a rotation speed of 2000 rpm and an acceleration of 500 rpm. -1 The substrate was then coated for 1 minute in a spin coater. Afterward, the substrate was removed and baked at 90°C for 1 minute. Subsequently, the substrate was placed in a UV contact lithography machine, a mask was applied, and photolithography exposure was performed using UV light at wavelengths of 254 nm and 365 nm, respectively. The exposure doses for the 254 nm and 365 nm UV light exposures were 7 mJ / cm², respectively. -2 and 300mJ cm -2 The development time was 15 seconds for both. After UV exposure, the substrate material was removed and placed in 1,2-diacetoxypropane for development. After development, the residual developer on the surface of the substrate material was dried with a nitrogen gun. The patterns obtained by photolithography exposure at wavelengths of 254 nm and 365 nm were observed using a metallurgical microscope, as shown below. Figure 1A , Figure 1B as well as Figure 2A , Figure 2B As shown.

[0056] Example 2

[0057] Take 0.01 g of 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine and 0.5 g of zirconium oxide nanoclusters (Zr6O4(OH)4(CH2=CCH3COO)). 12 The electron beam photoresist solution was dissolved in 9.5 g of propylene glycol monomethyl ether acetate solvent and stirred until completely dissolved. The solution was then filtered twice through a 0.22 μm pore size filter membrane. After filtration, the electron beam photoresist solution was placed in a brown glass bottle and stored at room temperature away from light.

[0058] Take an appropriate amount of the prepared electron beam photoresist solution and drop it onto the surface of a clean silicon wafer. Place the substrate material into the wafer at a rotation speed of 2000 rpm and an acceleration of 500 rpm. -1 The substrate was then coated in a spin coater for 1 minute. Afterward, the substrate was removed and placed in a drying oven at 90°C for 1 minute. Subsequently, the substrate was placed in an electron beam lithography machine for photolithography exposure using an electron beam as the light source. The exposure dose was 120 μC cm⁻¹ when using an electron beam as the light source. -2 The development time was 25 seconds. After electron beam exposure, the substrate material was removed and placed in 1,2-diacetoxypropane for development. After development, the residual developer on the surface of the substrate material was dried using a nitrogen gun. The pattern obtained by electron beam lithography was observed using a high-resolution scanning electron microscope, such as... Figure 3 As shown, the resolution of the pattern obtained by electron beam lithography is 60 nm.

[0059] As can be seen, the ultraviolet photoresist provided in Example 2 can be used for electron beam lithography to obtain a clear exposure pattern. When using an electron beam as a light source for lithography exposure, the exposure dose can be as low as 120 μC cm⁻¹. -2 the following.

[0060] Comparative Example

[0061] The preparation method in this embodiment is basically the same as that in Example 1, except that the photosensitizer is 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, and the exposure dosage is different. The specific steps are as follows:

[0062] Take 0.03 g of 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine and 0.75 g of zirconium oxide nanoclusters (Zr6O4(OH)4(CH2=CCH3COO)). 12The UV photoresist solution was dissolved in 14.25 g of propylene glycol monomethyl ether acetate solvent and stirred until completely dissolved. The solution was then filtered twice through a 0.22 μm pore size filter membrane. After filtration, the UV photoresist solution was placed in a brown glass bottle and stored at room temperature away from light.

[0063] Take an appropriate amount of the prepared UV photoresist solution and drop it onto the surface of a clean silicon wafer. Place the substrate material into the wafer at a rotation speed of 2000 rpm and an acceleration of 500 rpm. -1 The substrate was then coated for 1 minute in a spin coater. Afterward, the substrate was removed and baked at 90°C for 1 minute. Subsequently, the substrate was placed in a UV contact lithography machine, and a mask was applied. Photolithography exposure was performed using UV light at wavelengths of 254 nm and 365 nm, respectively. The exposure doses for the 254 nm and 365 nm UV light exposures were 18 mJ / cm², respectively. -2 and 400mJ cm -2 The development time was 15 seconds for both. After UV exposure, the substrate material was removed and placed in 1,2-diacetoxypropane for development. After development, the residual developer on the surface of the substrate material was dried with a nitrogen gun. The patterns obtained by photolithography exposure at wavelengths of 254 nm and 365 nm were observed using a metallurgical microscope, as shown below. Figure 4A , Figure 4B and Figure 5A , Figure 5B As shown.

[0064] As can be seen from Example 1 and the comparative example above, under the condition that the exposure light source is ultraviolet light with wavelengths of 254 nm and 365 nm, when 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine was used as a photosensitizer to react with zirconium oxide nanoclusters in Example 1, the exposure dose was 7 mJ / cm², respectively. -2 and 300mJ cm -2 In the comparative example, when 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine was used as a photosensitizer to react with zirconium oxide nanoclusters, the exposure dose was 18 mJ / cm². -2 and 400mJ cm -2 Therefore, compared with the comparative example, the photosensitizing effect of 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine as a photosensitizer interacting with zirconium oxide nanoclusters in Example 1 is better, with the exposure dose reduced by 61% and 25%, respectively. Example 1 can significantly reduce the ultraviolet exposure dose of the photoresist and improve the photolithography speed.

[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A type of ultraviolet photoresist, characterized in that, It is composed of an organic solvent, a photosensitizer, and zirconium oxide nanoclusters, wherein the general chemical formula of the zirconium oxide nanoclusters is Zr. x O y (OH) z L m , where 2≤x≤20, 2≤y≤40, 0≤z≤40, 4≤m≤40, and L is an organic ligand containing a carboxyl group; The photosensitizer has the following structure: Among them, R 1 for * indicates a connection site; R 2 and R 3 Each occurrence is independently selected from -F, -Cl, -Br, or -I.

2. The ultraviolet photoresist according to claim 1, characterized in that, The R 2 and R 3 All are -Cl.

3. The ultraviolet photoresist according to claim 1 or 2, characterized in that, The organic ligand containing a carboxyl group includes at least one of acrylic acid ligand, methacrylic acid ligand, 1-hydroxy-2-naphthoic acid ligand, and salicylic acid ligand.

4. The ultraviolet photoresist according to claim 1 or 2, characterized in that, The photosensitizer has a mass percentage content of 0.001% to 1%.

5. The ultraviolet photoresist according to claim 1 or 2, characterized in that, In the organic solvent, the zirconium oxide nanoclusters have a mass percentage content of 0.5% to 15%.

6. The ultraviolet photoresist according to claim 1 or 2, characterized in that, The organic solvent includes at least one of ethyl lactate, anisole, propylene glycol monomethyl ether acetate, methyl isobutyl ketone, and isopropanol.

7. A method for patterning ultraviolet photoresist, characterized in that, Includes the following steps: The ultraviolet photoresist according to any one of claims 1-6 is spin-coated onto a substrate and then dried to form an ultraviolet photoresist film; The ultraviolet photoresist film is exposed to ultraviolet light under a mask and then developed in a developer to form a photolithographic pattern.

8. The method according to claim 7, characterized in that, The developer comprises at least one of toluene, xylene, 1,2-diacetoxypropane, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, isopropanol, isobutanol, isoamyl alcohol, 4-methyl-2-pentanol, isopropoxyethanol, 1-methoxy-2-propanol, 1-propoxy-2-propanol, 1-butoxy-2-propanol, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, ethylene glycol butyl ether, propylene glycol ethyl ether, 2-heptanone, and 2-butanone.

9. The method according to claim 7, characterized in that, The light source for the ultraviolet lithography exposure is ultraviolet light with a wavelength of 365 nm, deep ultraviolet light with a wavelength of 254 nm, or extreme ultraviolet light with a wavelength of 13.5 nm.

10. The method for ultraviolet photoresist patterning according to claim 7, characterized in that, When the light source for ultraviolet lithography is deep ultraviolet light with a wavelength of 254 nm, the exposure dose is greater than or equal to 7 mJ / cm². -2 When the light source for ultraviolet lithography is 365nm wavelength ultraviolet light, the exposure dose is greater than or equal to 300 mJ / cm². -2 .

11. An electron beam photoresist, characterized in that, The ultraviolet photoresist according to any one of claims 1-6 is an electron beam photoresist.

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