Patent Application
20250197429
The present disclosure relates to organometallic compounds useful for the deposition of high purity tin oxide and highly purified forms of the organometallic compounds. More specifically, the present disclosure describes specific compounds useful in deposition of high purity tin oxide as well as compositions that result in improved reactivity and better stability.
Extreme ultraviolet (EUV) lithography enables a superb resolution of patterns that have been transferred onto a wafer substrate to form microchips. Unfortunately, traditional chemical amplified resists are highly transparent at an EUV wavelength of 13.5 nm (92 eV). Thus, there is a need in the industry to develop a new generation of photosensitive materials to enable production of smaller microchips for an array of technical applications.
One strategy to increase the sensitivity of photosensitive materials is an incorporation of atoms with enhanced absorptivity in the EUV regime, such as Sn, into the resist composition. Thus, there is a desire for Sn organometallics having high reactivity and stability for use as photo-sensitive materials in EUV processes and deposition processes.
Applicant determined that decreasing the bond energy of the Sn-C bond could improve performance of the Sn photosensitive materials in certain uses (photolytic cleavage of Sn-C bonds during exposure to EUV would promote cross-linking hence making these materials superior negative photoresist). Ligands containing unsaturated hydrocarbons, such as allyl, may provide decreased bond energy of the Sn-C bond.
Despite the foregoing advantages of decreasing the bond energy of the Sn-C bond in photosensitive materials, it is also contemplated that strengthening the Sn-C bond in photosensitive materials may also be advantageous in photosensitive materials in other uses. Ligands containing unsaturated hydrocarbons, such as vinyl, may provide increased bond energy of the Sn-C bond. By strengthening the Sn-C bond, some ligands bonded to Sn may be retained in the deposited film for further EUV treatment, which may be advantageous in particular uses.
In addition, amino, alkoxy, or halide ligands enable reactivity with OH groups of wafers/substrate layers for effective ALD deposition. Thus, Applicant discovered that organometallics of tin having a combination of ligands containing unsaturated hydrocarbons and ligands containing amino, alkoxy, or halide ligands have improved properties for deposition, especially atomic layer deposition, and for use as a photosensitive material in patterning applications.
In one aspect, disclosed are organometallic compounds of Formula I, below:
In embodiments, R is an allyl or vinyl group. In some embodiments, the allyl or vinyl group can be straight chain. Alternatively, the allyl group can be a substituted allyl group having the general formula: CR4R5CR6═CR7R8, wherein R4, R5, R6, R7, and R8 are each independently selected from the group consisting of H and alkyl groups having from 1 to 4 carbon atoms. Similarly, the vinyl group can be a substituted vinyl group having the general formula: CR9═CR10R11, wherein R9, R10, and R11 are each independently selected from the group consisting of H and alkyl groups having from 1 to 4 carbon atoms.
In other embodiments, R is Cp, which is a cyclopentadienyl group having R12, R13, R14, R15, and R16 constituents. Depending on A, Cp can be substituted or unsubstituted. R12, R13, R14, R15, and R16 each independently selected from H and an alkyl group having from 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. R12, R13, R14, R15, and R16 can be the same or different. However, when A is NR1R2, pyrrolidinyl, pyrrolyl, or halide, at least one of R12, R13, R14, R15, and R16 is an alkyl group having from 1 to 10 carbon atoms.
In any of the above-mentioned embodiments, A is NR1R2. In such embodiments, R1 and R2 are independently selected from an alkyl group having from 1 to 4 carbon atoms. In embodiments R1 and R2 are methyl or ethyl. In embodiments R1 and R2 are different.
Alternatively, A can be OR3. In such embodiments R3 is an alkyl group having from 1 to 4 carbon atoms. In embodiments R3 is methyl, ethyl, or tert-butyl. In other embodiments, A is one of pyrrolyl, pyrrolidinyl, or halide.
In embodiments, the organometallic compound is selected from the group consisting of (CH2═CHCH2)Sn(NMe2)3, (CH2═CHCH2)Sn(NEt2)3, (CH2═CHCH2)Sn(NEtMe)3, (CH2═CHCH2)Sn(Pyrrolidinyl)3, (CH2═CH)Sn(NMe2)3, (CH2═CH)Sn(NEt2)3, (CH2═CH)Sn(NEtMe)3, (CH2═CH)Sn(Pyrrolidinyl)3, (Cp)Sn(NMe2)3, (Cp)Sn(NEt2)3, (Cp)Sn(NEtMe)3, (Cp)Sn(Pyrrolidine)3, (CH2═CHCH2)2Sn(NMe2)2, (CH2═CHCH2)2Sn(NEt2)2, (CH2═CHCH2)2Sn(NEtMe)2, (CH2═CHCH2)2Sn(Pyrrolidine)2, (CH2═CH)2Sn(NMe2)2, (CH2═CH)2Sn(NEt2)2, (CH2═CH)2Sn(NEtMe)2, (CH2═CH)2Sn(Pyrrolidine)2, (Cp)2Sn(NMe2)2, (Cp)2Sn(NEt2)2, (Cp)2Sn(NEtMe)2, (Cp)2Sn(Pyrrolidine)2, (CH2═CHCH2)3Sn(NMe2), (CH2═CHCH2)3Sn(NEt2), (CH2═CHCH2)3Sn(NEtMe), (CH2═CHCH2)3Sn(Pyrrolidine), (CH2═CH)3Sn(NMe2), (CH2═CH)3Sn(NEt2), (CH2═CH)3Sn(NEtMe), (CH2═CH)3Sn(Pyrrolidine), (Cp)3Sn(NMe2), (Cp)3Sn(NEt2), (Cp)3Sn(NEtMe), (Cp)3Sn(Pyrrolidine).
Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, of which:
Before describing several exemplary embodiments, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.
Reference throughout this specification to “one embodiment,” “certain embodiments,” “one or more embodiments” or “an embodiment” means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases such as “in one or more embodiments,” “in certain embodiments,” “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.
Although reference herein is to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention include modifications and variations that are within the scope of the appended claims and their equivalents.
Reference throughout this specification to “a” or “an” represents one or more and is not limited to singular form, unless explicitly stated.
The following detailed description can be read in connection with the accompanying drawings in which like numerals designate like elements.
Disclosed are organometallic compounds of Formula I, below:
Also disclosed are high-purity organometallic compounds and methods of purifying the organometallic compounds.
Applicant discovered that during synthesis of compounds of Formula I, dissociation occurred. For example, molecules of (CH2═CHCH2)2Sn(NMe2)2, a product, underwent significant ligand exchange, resulting in the formation of side products, such as (CH2═CHCH2)Sn(NMe2)3 and (CH2═CHCH2)3Sn(NMe2). It is contemplated that bulkier ligands, such as substituted allyl, substituted vinyl, substituted or unsubstituted Cp, which is cyclopentadienyl, heavier amines, or heavier alkoxies in the compound of Formula I may be able to prevent side product creation and improve stability by reducing ligand exchange.
In embodiments, R is an allyl group having the general formula: CR4R5CR6═CR7R8, wherein R4, R5, R6, R7, and R8 are each independently selected from the group consisting of H and alkyl groups having from 1 to 4 carbon atoms, such as methyl, ethyl, propyl, iso-propyl, tert-butyl, iso-butyl, or n-butyl. R4, R5, R6, R7, and R8 can be the same or different. In embodiments, at least one of R4 and R5 is not H, such as 1,1-dimethylallyl, wherein R4 and R5 are both methyl. In embodiments R6 is not H, such as 2-methylallyl. In embodiments at least one of R7 and R8 is not H, such as 3,3-dimethylallyl. In some embodiments, x is 2 and compounds of Formula I are represented by the following formula: (CR4R5CR6═CR7R8)2Sn(A)2, wherein A is NR1R2, OR3, pyrrolidinyl, pyrrolyl, or halide.
In other embodiments, R is a vinyl group having the general formula: CR9═CR100R11, wherein R9, R10, and R11are each independently selected from the group consisting of H and alkyl groups having from 1 to 4 carbon atoms, such as methyl, ethyl, propyl, iso-propyl, tert-butyl, iso-butyl, or n-butyl. R9, R10, and R11 can be the same or different. In embodiments, R9 is not H, such as 1-ethylvinyl. In embodiments at least one of R10 and R11 is not H, such as 2,2-dimethylvinyl. In some embodiments, x is 2 and compounds of Formula I are represented by the following formula: (CR9═CR10R11)2Sn(A)2, wherein A is NR1R2, OR3, pyrrolidinyl, pyrrolyl, or halide.
Any of the above-mentioned compounds of Formula I include those in which x is 1. In such embodiments, Compounds of Formula I are represented by the following formula: (R)Sn(A)3, wherein R is a non-cyclic unsaturated hydrocarbon having 2 to 10 carbon atoms.
Compounds of Formula I also include those in which x is 3. In such alternative embodiments, compounds of Formula I are represented by the following formula: (R)3Sn(A), wherein R is a non-cyclic unsaturated hydrocarbon having 2 to 10 carbon atoms.
Any of the above-mentioned compounds of Formula I represented by the formula: (R)xSn(A)4−x include those in which R is a non-cyclic unsaturated hydrocarbon having 2 to 8 carbon atoms. Further, Compounds of Formula I include those in which R is a non-cyclic unsaturated hydrocarbon having 2 to 4 carbon atoms.
Any of the above-mentioned compounds of Formula I include those in which A is NR1R2. R1 and R2 are independently selected from H, alkyl groups having from 1 to 10 carbon atoms, aryl groups, or acyl groups. R1 and R2 can be the same or different. In a particular embodiment, R1 and R2 are each alkyl groups having 1 to 10 carbons atoms. In a more particular embodiment, R1 and R2 are each alkyl groups having from 2 to 4 carbon atoms. More particularly, R1 and R2 can each be selected from the group consisting of methyl, ethyl, propyl, iso-propyl, tert-butyl, iso-butyl, and n-butyl.
For any of the above-mentioned compounds, it is contemplated that R can be either a straight-chain unsaturated hydrocarbon or a branched unsaturated hydrocarbon.
Any of the above-mentioned compounds of Formula I also include those in which A is OR3. In such embodiments, compounds of Formula I are represented by the formula: (R)xSn(OR3)4−x, wherein R3 is an alkyl group having 2 to 8 carbon atoms. In other embodiments, R3 is selected from the group consisting of an alkyl group having from 1 to 4 carbon atoms. More particularly, R3 can be selected from the group consisting of methyl, ethyl, propyl, iso-propyl, tert-butyl, iso-butyl, and n-butyl.
When A is an alkoxy group, such as OR3, R can be Cp. In such embodiments, compounds of Formula I are represented by the formula: (Cp)xSn(OR3)4−x, wherein Cp is a cyclopentadienyl group having R12, R13, R14, R15, and R16 constituents. Cp can be unsubstituted, wherein R12, R13, R14, R15, and R16 are H, or substituted, wherein at least one of R12, R13, R14, R15, and R16 is independently selected from an alkyl group having from 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. R12, R13, R14, R15, and R16 can be the same or different.
When A is an amine group, such as NR1R2, or pyrrolidinyl, pyrrolyl, or halide, R can be substituted Cp, wherein at least one of R12, R13, R14, R15, and R16 is independently selected from an alkyl group having from 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl. R12, R13, R14, R15, and R16 can be the same or different.
Compounds of Formula I include those in which A is pyrrolidinyl or pyrrolyl. Such embodiments are respectively represented by the general formula: (R)xSn(Pyrrolidinyl)4−x or (R)xSn(Pyrrolyl)4−x. It is contemplated that A could also be a halide, such as chloro, bromo, or iodo.
When R is Cp, compounds of Formula I, (Cp)xSn(A)4−x may be synthesized as follows. In a glovebox, load a 1 L round bottom flask with SnCl4 and anhydrous hexanes. Add 1 equiv. of NaCp* (NaC5Me5) drop-wise while cooling. Leave the reaction mixture stirring at room temperature for 1 hour. Return the reaction flask into a cooling bath and add 3 equiv. of NaOMe in anhydrous THF to the flask. Remove solvents via reduced pressure distillation. Isolate the product via sublimation.
Particular organometallic compounds of Formula I include the following: (CH2═CHCH2)Sn(NMe2)3, (CH2═CHCH2)Sn(NEt2)3, (CH2═CHCH2)Sn(NEtMe)3, (CH2═CHCH2)Sn(Pyrrolidinyl)3, (CH2═CH)Sn(NMe2)3, (CH2═CH)Sn(NEt2)3, (CH2═CH)Sn(NEtMe)3, (CH2═CH)Sn(Pyrrolidinyl)3, (Cp)Sn(NMe2)3, (Cp)Sn(NEt2)3, (Cp)Sn(NEtMe)3, (Cp)Sn(Pyrrolidine)3, (CH2═CHCH2)2Sn(NMe2)2, (CH2═CHCH2)2Sn(NEt2)2, (CH2═CHCH2)2Sn(NEtMe)2, (CH2═CHCH2)2Sn(Pyrrolidine)2, (CH2═CH)2Sn(NMe2)2, (CH2═CH)2Sn(NEt2)2, (CH2═CH)2Sn(NEtMe)2, (CH2═CH)2Sn(Pyrrolidine)2, (Cp)2Sn(NMe2)2, (Cp)2Sn(NEt2)2, (Cp)2Sn(NEtMe)2, (Cp)2Sn(Pyrrolidine)2, (CH2═CHCH2)3Sn(NMe2), (CH2═CHCH2)3Sn(NEt2), (CH2═CHCH2)3Sn(NEtMe), (CH2═CHCH2)3Sn(Pyrrolidine), (CH2═CH)3Sn(NMe2), (CH2═CH)3Sn(NEt2), (CH2═CH)3Sn(NEtMe), (CH2═CH)3Sn(Pyrrolidine), (Cp)3Sn(NMe2), (Cp)3Sn(NEt2), (Cp)3Sn(NEtMe), (Cp)3Sn(Pyrrolidine).
Decreasing the bond strength of the Sn-C bond could improve performance of the Sn photosensitive materials during photolytic cleavage of Sn-C bonds upon exposure to EUV. It would promote cross-linking hence making these materials superior negative photoresist. Unsaturated hydrocarbons, such as allyl ligands, are great compounds for this application. Additionally, the presence of a Sn-allyl bond would improve the reactivity of this molecule during SnO2 film formation.
Increasing the bond strength of the Sn-C bond may also be advantageous in photosensitive materials. Ligands containing unsaturated hydrocarbons, such as vinyl, may provide increased bond energy of the Sn-C bond. By strengthening the Sn-C bond, some ligands bonded to Sn may be retained in the deposited film for further EUV treatment, which may be advantageous.
Compounds of Formula I may be prepared by processes known in the art. The examples below are illustrative of such processes but are not intended to be limiting.
On a double manifold, a small Schlenk flask was loaded with 6.0 mL of SnCl4 (51 mmol), ca. 60 mL of anhydrous toluene, and a magnetic stir bar. While stirring at room temperature, 4.1 mL of Sn(allyl)4 (17mmol) was added drop-wise. The reaction mixture was stirred at 22° C. for 90 minutes. A small aliquot was collected for 1H NMR and 119Sn NMR analysis and confirmed the formation of (CH2═CHCH2)Sn(Cl)3 as shown in
On a double manifold, a small Schlenk flask was loaded with 2.0 mL of SnCl4 (17mmol), ca. 30mL of anhydrous toluene, and a magnetic stir bar. While stirring at room temperature, 4.1 mL of Sn(allyl)4 (17mmol) was added drop-wise. The reaction mixture was stirred at 22° C. for 90 minutes. A small aliquot was collected for 1H NMR and 119Sn NMR analysis and confirmed the formation of (CH2═CHCH2)2Sn(Cl)2 as shown in
On a double manifold, a 1 L round bottom flask was loaded with 82 mL of BuLi (2.5M in hexanes, 0.205 mol), ca. 500 mL of anhydrous toluene and a magnetic stir bar. The flask was placed in an ice-water bath and HNMez was bubbled through the reaction mixture for 20 minutes at a rate of 284 mL per minute (0.251 mol). The reaction flask was removed from the cooling bath and left to stir at 22° C. for 90 minutes.
Meanwhile, (CH2═CHCH2)2Sn(Cl)2 was prepared by reacting 6.0 mL of SnCl4 (0.051 mol) in ca. 100 mL of anhydrous toluene and 12.3 mL of Sn(allyl)4 (0.051 mol). This reaction was stirred at 22° C. for 60 minutes. The flask containing (CH2═CHCH2)2Sn(Cl)2 was returned to an ice-water bath where an LiNMe2 mixture was slowly added drop-wise via cannulation to the flask. The final reaction mixture was removed from the cooling bath and stirred at 22° C. for 50 minutes.
Stirring was stopped to allow the LiCl salts to settle down overnight. The next day, the liquid layer was transferred into a new round bottom flask. The solvent was removed via reduced pressure distillation. The final product was isolated via reduced pressure distillation (40° C. at 2.0-4.5×10−2 Torr). A significant ligand exchange of (CH2═CHCH2)2Sn(NMe2)2 has been detected resulting in the formation of (CH2═CHCH2)SN(NMe2)3 and (CH2═CHCH2)3Sn(NMe2) Eventually, the product distribution reaches 50:25:25 mol %.
(CH2═CHCH2)3Sn(NMe2): 1H NMR (300 MHz, C6D6) (
(CH2═CHCH2)2Sn(NMe2)2: 1H NMR (300 MHz, C6D6) (
(CH2═CHCH2)Sn(NMe2)3: 1H NMR (300 MHz, C6D6) (
Example 4: Synthesis of (CH2═CHCH2)2Sn(NEt2)2
On a double manifold, a Schlenk flask was loaded with 27.5 mL of nBuLi (2.5M in hexanes, 0.069 mol), ca. 125 mL of anhydrous toluene and a magnetic stir bar. The flask was placed in an ice-water bath and HNEt2 (7.4 mL, 0.072 mol) in ca. 20 mL of anhydrous toluene was added to the reaction flask drop-wise. The reaction flask was removed from the cooling bath and left to stir at 22° C. for 40 minutes.
Meanwhile, (CH2═CHCH2)2Sn(Cl)2 was prepared by reacting 2.0 mL of SnCl4 (0.017 mol) in ca. 80 mL of anhydrous toluene and 4.1 mL of Sn(allyl)4 (0.017 mol). This reaction was stirred at 22° C. for 60 minutes. The flask containing (CH2 ═CHCH2)2Sn(Cl)2 was returned to an ice-water bath and the LiNMe2 mixture was slowly added drop-wise via cannulation to the flask. The final reaction mixture was removed from the cooling bath and stirred at 22° C. for 30 minutes before proceeding with distillation under reduced pressure to removed solvent and collect the product (80° C. at 0.05 Torr).
Characterization: 1H NMR (300 MHz, C6D6): 1.08 ppm (t, 3JHH=6.9 Hz, 12H, N(CH2CH3)), 1.95 ppm (dd, 2JHH=1.5 Hz; 3JHH=1.0 Hz, 2H, allyl CH2), 1.98 ppm (dd, 2JHH=1.5Hz; 3JHH=1.0 Hz, 2H, allyl CH2), 3.04 ppm (q, 3JHH=6.9 Hz, 8H, N(CH2CH3)), 4.86 ppm (m, 2H, allyl CH2), 4.98 ppm (m, 2H, allyl CH2), 5.9 ppm (m, 2H, allyl CH). 119Sn NMR (134.35 MHz, C6D6): −24.8 ppm.
Example 5: Synthesis of (CH2═CHCH2)2Sn(NiPr2)2
On a double manifold, a 1 L round bottom flask was loaded with 29.9 mL of nBuLi (2.5M in hexanes, 0.075 mol), ca. 500 mL of anhydrous toluene and a magnetic stir bar. The flask was placed in an ice-water bath and HNiPr2 (11 mL, 0.079 mol) in ca. 20 mL of anhydrous toluene was added to the reaction flask drop-wise. The reaction flask was removed from the cooling bath and left to stir at 22° C. overnight. The reaction flask was then transferred into the ice-water bath.
Meanwhile, (CH2═CHCH2)2Sn(Cl)2 was prepared by reacting 2.19 mL of SnCl4 (0.019 mol) in ca. 100 mL of anhydrous toluene and 4.49 mL of Sn(allyl)4 (0.019 mol). This reaction was stirred at 22° C. for 3h. The (CH2═CHCH2)2Sn(Cl)2 mixture was slowly added drop-wise to the round bottom flask via cannulation. The final reaction mixture was removed from the cooling bath and stirred at 22°° C. overnight. After removing solvents from the final product mixture, the product and some free amine in the residue have been characterized. This product is a solid and shows no signs of ligand exchange.
Characterization: 1H NMR (300 MHz, C6D6) (
Example 6: Synthesis of (CH2═CH)3SnCl
Synthesis of this complex was based on Sanders D. Rosenberg & Ambrose J. Gibbons Jr., The Disproportionation of Tetravinyltin with Tin Tetrachloride and the Cleavage of Some Vinyltin Compounds with Bromine, 79 J. AM. CHEM. SOC'Y. 2138 (1957), https://doi.org/10.1021/ja01566a029 [hereinafter Rosenberg & Gibbons]. This complex was not isolated and was used in the following salt metathesis reaction steps. Characterization: 1H (300 MHz, C6D6): dd 5.77 ppm (3JHH=2.7 Hz, 3JHH=19.9 Hz, 3H, vinyl-CH), dd 5.98 ppm (3JHH=2.7 Hz, 3JHH=13.4 Hz, 3H, vinyl-CH), dd 6.14 ppm (3JHH=13.4 Hz, 3JHH=19.9 Hz, 3H, vinyl-CH). 119Sn (186 MHz, C6D6): s−53.8 ppm.
Example 7: Synthesis of (CH2═CH)3Sn(NEt2)
On a double manifold, a 500 mL round bottom flask was loaded with 10.5 mL of nBuLi (2.5M in hexanes, 0.0263 mol), ca. 250 mL of anhydrous hexane and a magnetic stir bar. HNEt2 (2.8 mL, 0.027 mol) was added to the reaction flask drop-wise. The reaction mixture was left to stir at 22° C. for 60 minutes.
Meanwhile, (CH2═CH)3SnCl was prepared by reacting 3.5 mL of Sn(vinyl)4 (0.019 mol) and 0.8 mL of SnCl4 (0.0068mol). This reaction was stirred at 40° C. for 90 minutes. See Rosenberg & Gibbons.
Proceed with a slow addition of (CH2═CH)3SnCl mixture into LiNEt2 mixture via cannulation. The final reaction mixture was stirred at 22° C. overnight. Next day proceed with solvent removal via reduced pressure distillation followed by product collection in a separate receiving flask (0.08 Torr at 35° C.) to collect 5.2 g of the product (75% yield).
Characterization: 1H (500 MHz, C6D6) (
In the glovebox, a small Schlenk flask was loaded with 1.2 mL of Sn (NMe2)4 (4.7 mmol) and ca. 13 mL of anhydrous THF. Add 0.679 g of NaCpiPr (5.2 mmol). Transfer this Schlenk flask onto the double manifold and proceed with reflux at 76° C. for 4 hours. NMR analysis of the reaction mixture confirms formation of CpiPrSn (NMe2)3. When isolated, this product is a solid.
Characterization: 1H (500 MHz, C6D6): d 1.36 ppm (3JHH=6.7 Hz, 6H, iPr-CH3), s 3.06 ppm (3JH119Sn=42.1 Hz, 3JH117Sn=40.4 Hz, 18H, NMe2), sept 3.18 (3JHH=6.7 Hz, 1H, iPr-CH), m 6.21 (2H, Cp-H), m 6.32 (2H, Cp-H). 119Sn (186 MHz, C6D6) (
Compounds of Formula I could have improved thermal stability and surface reactivity compared to those known in the art, which may result in improved ALD films. Poor thermal stability can hinder reactivity of the precursor with the substrate surface during ALD deposition, that is, the precursor should not decompose prior to ALD deposition. In contrast to ALD, in CVD processes, high energy and temperature are used to react the precursors at process temperature. Then, the already-reacted precursors react on the substrate. Because the CVD process uses substantially larger energy and breaks apart the precursors prior to the reaction, the reactivity of the precursors is not as important in CVD processes as in ALD processes.
The deposited intermediate part 1a is then illuminated with extreme ultraviolet (EUV) light through the mask(s) 40 resulting in a photolytic cleavage of Sn-C bonds that promotes cross-linking. After illumination, the deposited intermediate part 1a is baked to densify the SnO2 layers. Then, the glass mask 50 is removed.
A development step is illustrated in
During the etching step, shown in
Lastly, the exposed portion 30B of the layer of photosensitive material 30 is removed, leaving behind the desired pattern.
Compounds of Formula I are particularly advantageous for negative resist deposition methods because tuning the bond energy of Sn-C by using allyl or vinyl ligands improves performance of the Sn photosensitive materials. It is contemplated that photolytic cleavage of Sn-C bonds during exposure to EUV light will promote cross-linking, thus making these materials superior over those known in the art.
From theoretical modeling of the activation energy required to strip off ligands from molecules via hydrolysis reaction, a wide range in activation energies between molecules is observed. Hence differences in reactivity are observed. This shows the likelihood that the molecule would be a highly reactive molecule for the formation of SnO2 when the activation energy is low, but this value also shows that the molecule might be more prone to decomposition and reaction during the synthesis and purification processes. Accordingly, obtaining purity of compounds within the scope of Formula I will be difficult to obtain, especially assay purity of greater than 95% or even greater than 99%.
However, using multistage vacuum distillation can obtain greater than 95% or even greater than 99% assay purity for compounds in the scope of Formula I. Various forms of multistage distillation are known in the chemical manufacturing industry, but have not been employed for the purification of organometallic materials that include compounds of Formula I.
As illustrated by the schematic shown in
The apparatus can be seen as a sequence of closed spaces separated by tube walls, with a heat source at one end and a heat sink at the other. Each space is at pressure below atmospheric conditions via vacuum. Each space consists of two communicating subspaces, the exterior of the tubes of stage n and the interior of the tubes in stage n+1. Each space has a lower temperature and pressure than the previous space, and the tube walls have intermediate temperatures between the temperatures of the fluids on each side. The pressure in a space cannot be in equilibrium with the temperatures of the walls of both subspaces; it has an intermediate pressure. As a result, the pressure is too low or the temperature too high in the first subspace, and the feed material evaporates. In the second subspace, the pressure is too high or the temperature too low, and the vapor condenses. This carries evaporation energy from the warmer first subspace to the colder second subspace. At the second subspace the energy flows by conduction through the tube walls to the colder next space.
This application claims priority to U.S. Provisional Application No. 63,334,430 filed Apr. 25, 2022, which is incorporated herein in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2023/054018 | 4/20/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63334430 | Apr 2022 | US |
