Trinuclear tin complexes, methods of making, and use in euvl and e-beam lithography

Abstract

The application discloses a kind of trinuclear tin complex, its preparation method and application in extreme ultraviolet lithography and electron beam lithography.The trinuclear tin complex has the following general formula I structure;It is prepared by the reaction of tin core with R1 substituent group modification and isophthalic acid with R2 substituent group modification according to the molar ratio of 1:1-2 in solvent;The trinuclear tin complex disclosed in the application connects different ligands, enhances the thermal chemical stability of the whole trinuclear tin complex, improves the EUV absorption rate, the molecular size is small, the composition is single, the Sn-C bond is broken during exposure to initiate high efficient solubility transformation, the sensitivity is far more than similar products, especially in electron beam lithography, performance revolution is improved.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical materials, and in particular relates to a class of trinuclear tin complexes, their preparation methods, and their applications in extreme ultraviolet lithography and electron beam lithography. Background Technology

[0002] Photolithography, a core step in semiconductor chip manufacturing, has a crucial impact on the final chip performance due to its precision and complexity. The initial step in photolithography is exposure. In this stage, a specific light source (such as deep ultraviolet or extreme ultraviolet light) shines through a mask with a precise pattern onto a silicon wafer coated with photoresist. Subsequently, the solubility of the exposed and unexposed areas undergoes a sudden change. If the solubility of the exposed area decreases, it is a negative photoresist; conversely, if the solubility increases, it is a positive photoresist. After exposure, the silicon wafer undergoes a step called post-exposure baking (PEB). This step primarily uses heat to accelerate the chemical reactions in the photoresist, making it more stable and ensuring the precision of the pattern. Then comes the development step. In this stage, a specific developer is used to wash away the unwanted photoresist areas on the silicon wafer, leaving the photoresist pattern corresponding to the pattern on the mask. This step is crucial in the photolithography process because it directly affects the precision and quality of the circuitry on the final chip. Finally, through an etching step, using photoresist as a protective layer, the portions of the silicon wafer not covered by the photoresist are etched away, thereby transferring the pattern from the mask onto the silicon wafer. After etching, a series of cleaning and photoresist removal steps are performed to finally obtain a silicon wafer with a specific circuit pattern.

[0003] With the development of microelectronics technology, the demand for continuously miniaturized feature sizes has driven the continuous advancement of photolithography technology. The exposure wavelengths of photolithography machines have also evolved from the ultraviolet g-line (436nm) to the i-line (365nm) to 248nm to 193nm to extreme ultraviolet (EUV). EUV lithography, using extreme ultraviolet light with wavelengths of 10-14 nanometers as the light source, has become the mainstream trend in photoresist development. EUV lithography can directly pattern sub-20 nanometer half-pitch resolution, making it the most promising nanoscale manufacturing technology. However, the limited brightness of the EUV light source and the limited reflectivity of the multilayer mirrors place new demands on the sensitivity of the photoresist. Furthermore, the high-resolution patterning characteristics of EUV require photoresist materials with smaller component sizes as a support.

[0004] To meet the new requirements of EUV lithography, various novel advanced metal-containing photoresists have been developed in recent years, such as metal nanoparticle photoresists, metal complex photoresists, metal oxide cluster photoresists, and metal-modified polymer photoresists. Metal complex photoresists, such as zinc, antimony, chromium, and tin complexes, are particularly valuable due to their high EUV absorption, small molecular size, and high corrosion resistance. Among these, trinuclear tin complex photoresists show the most promising application prospects due to the high extreme ultraviolet absorption characteristics of tin.

[0005] Currently, only a few papers have been published on trinuclear tin complex photoresists, and only one paper has a structure similar to that of this study: *Induced Chemical Networking of Organometallic Tin in a Cyclic Framework for Sub-10nm Patterning and Interconnect Application*, ACS Applied NanoMaterials, 2023, Vol. 6, No. 6. This paper develops an organometallic tin-based photoresist, but only describes electron beam lithography (EBL) and helium ion beam lithography (HIBL), without applying extreme ultraviolet lithography (EUVL). Furthermore, the sensitivity (D...) of the trinuclear tin complex photoresist in this paper... 0.5 Approximately 1900 μC / cm 2 (28keV). Although Sn-CT photoresists have demonstrated superior performance in electron beam lithography (EBL) and helium ion beam lithography (HIBL), their potential in extreme ultraviolet lithography (EUVL) has not yet been fully realized. EUV lithography is highly valued for its high resolution and important role in integrated circuit manufacturing; however, limitations in light source brightness and reflectivity place higher demands on the sensitivity and chemical stability of photoresists. This indicates that the applicability and performance optimization of Sn-CT photoresists in EUV lithography still require in-depth research to meet the stringent requirements of this cutting-edge technology, highlighting the room for improvement in photoresist technology when adapting to emerging lithography technologies such as EUV. Summary of the Invention

[0006] To overcome the shortcomings of existing EUV photoresists, such as low sensitivity and insufficient patterning resolution, this invention provides a class of trinuclear tin complexes with high sensitivity and high patterning resolution, their preparation method, and their application in extreme ultraviolet lithography and electron beam lithography.

[0007] To achieve the above objectives, the technical solution of the present invention is: a class of trinuclear tin complexes, wherein the trinuclear tin complexes have the structure of general formula I.

[0008]

[0009] In general formula I,

[0010] R1 is selected from alkyl groups having 1-18 carbons;

[0011] R2 is selected from one of an alkyl group having 0-18 carbons, an alkenyl group having 2-18 carbons, or an aromatic group having 6-20 carbons.

[0012] In the case of further optimization:

[0013] R1 is selected from straight-chain or branched alkyl groups having 4-10 carbon atoms;

[0014] R2 is selected from one of a straight-chain or branched alkyl group having 1-6 carbons, an alkenyl group having 2-6 carbons, or an aromatic group having 6-10 carbons.

[0015] In a further preferred embodiment: R1 is selected from n-butyl or n-octyl; R2 is selected from methyl, vinyl or phenyl.

[0016] In a further preferred embodiment: R1 is selected from n-octyl; R2 is selected from vinyl.

[0017] Furthermore, this invention also provides a method for synthesizing a class of trinuclear tin complexes having the above-described general formula I structure:

[0018] Tin cores modified with R1 substituents were reacted with isophthalic acid modified with R2 substituents in a solvent mixture at a molar ratio of 1:1 to 2. After the reaction was completed, the mixture was cooled, filtered, washed, solvent removed, and vacuum dried to obtain a solid product.

[0019] The reaction includes: using anhydrous methanol as a solvent, reacting at 64.7–70°C for 20–24 h; or using a mixed solvent of toluene and ethanol in a volume ratio of 4–6:1 and a Dean-Starck apparatus, reacting at 105–110°C for 8–12 h.

[0020] In a further preferred embodiment of the above-described technical solution, the first synthesis method involves reacting dihydroxytin modified with R1 substituents and isophthalic acid modified with R2 substituents in anhydrous methanol at a molar ratio of 1:1 to 2, at a reaction temperature of 64.7 to 70°C, for a reaction time of 20 to 24 hours. After the reaction is completed, the mixture is cooled, filtered, washed, and vacuum dried to obtain a solid product.

[0021] For the technical solution described above, its reaction formula is as follows:

[0022]

[0023] In a further preferred embodiment of the above-described technical solution, the second synthesis method involves reacting tin oxide modified with R1 substituents and isophthalic acid modified with R2 substituents in a toluene:ethanol mixture with a volume ratio of 4 to 6 to 1 in a molar ratio of 1:1 to 2. The reaction vessel is a Dean-Starck apparatus with a condenser, the reaction temperature is 105 to 110°C, and the reaction time is 8 to 12 hours. After the reaction is complete, the insoluble matter is removed by hot filtration, the solvent mixture is removed by vacuum rotary evaporation, and the obtained solid product is washed, filtered, and vacuum dried to obtain a pure solid product.

[0024] For the technical solution described above, its reaction formula is as follows:

[0025]

[0026] Furthermore, the mass ratio of the mixture of tin dichloride or tin oxide modified with R1 substituent and isophthalic acid modified with R2 substituent to the organic solvent is 1g:15-25ml.

[0027] Application of a class of trinuclear tin complexes in extreme ultraviolet lithography and electron beam lithography, wherein the trinuclear tin complexes are used as photosensitizers and resins in photoresist formulations.

[0028] Furthermore, in the above-described application, the photoresist is prepared by the following method: chloroform is added to the trinuclear tin complex at a ratio of 10-20 mg: 1-2 ml, and the mixture is ultrasonically treated for 10-30 min and then filtered to obtain a photoresist solution.

[0029] Furthermore, in the above-described application, the tri-core tin complex serves as a photosensitizer and resin in the electron beam photoresist formulation, enabling the patterning of 19–30 nm linewidth lines with high sensitivity in electron beam lithography.

[0030] Furthermore, in the above-described application, the trinuclear tin complex, as a photosensitizer and resin in the extreme ultraviolet (EUV) photoresist formulation, can complete patterning with a linewidth of 20–30 nm at a period of 50–100 nm during EUV lithography exposure.

[0031] The present invention has the following beneficial effects:

[0032] 1. This invention utilizes aromatic carboxylic acids and their derivatives as ligands. These compounds generally have higher boiling and melting points than fatty acids and their derivatives, are less volatile, and have good thermal stability, chemical stability, solid stability, solution stability, and storage stability, making the photoresist more reliable in preparation and use.

[0033] 2. The trinuclear tin complex provided by this invention has a trinuclear tin macrocyclic structure. Tin metal has a high EUV absorption rate, which means that more photons can be used in the extreme ultraviolet lithography process to reduce the influence of photon emission noise, increase the yield of secondary electrons, and thus improve quantum utilization efficiency.

[0034] 3. The tin core and aromatic ligands of the trinuclear tin complex are tightly linked by chemical bonds to form a ring, which is structurally stable and has a small molecular size of only about 2 nm. The small molecular size is conducive to the rapid transition from the soluble region to the insoluble region, which is beneficial to the clear boundary between the soluble region and the insoluble region in the photolithography process.

[0035] 4. The tri-core tin complex photoresist provided by this invention has a well-defined structure and a single composition. It does not require additives such as photoacid generators, surfactants, thickeners, and quenchers. The single composition helps to alleviate the roughness problem caused by uneven distribution of components and insufficient reaction of photoresist in different areas.

[0036] 5. The trinuclear tin complex of the present invention, by introducing a preferred carboxylic acid ligand, provides more photochemical reaction pathways during exposure, thereby giving the photoresist higher reactivity: compared with ordinary metal-based photoresists, it has more Sn-C bond reaction sites. During exposure, the Sn-C bonds undergo homolytic cleavage under irradiation, generating alkyl radicals. The generated alkyl radicals will trigger a series of reactions, causing a change in solubility. Compared with other monocoordinate tin-oxygen cluster photoresists, it has more reaction sites, resulting in higher sensitivity and a smaller dose required during exposure.

[0037] 6. In addition to having higher sensitivity than most other metal-based photoresists, the trinuclear tin complex of this invention, compared with a structurally similar trinuclear tin complex already disclosed (mentioned in the background art), not only offers new exposure applications under extreme ultraviolet lithography, but also exhibits higher sensitivity under electron beam lithography. Photoresists containing preferred carboxylic acid ligands show higher sensitivity (D...). 0.5 Approximately 60 μC / cm 2 (30keV), compared to the sensitivity of publicly available tri-core tin complex photoresist (D 0.5 1900μC / cm 2 (28keV), the sensitivity is increased by more than 31 times, showing a revolutionary performance improvement.

[0038] 7. When the trinuclear tin photoresist provided by the present invention is applied to extreme ultraviolet lithography and electron beam lithography, such as trinuclear tin complexes containing carboxylic acid ligands preferably 5-vinyl isophthalic acid, in addition to the crosslinking reaction that occurs at the Sn core after the Sn-C bond breaks during the exposure process, an ethylene crosslinking reaction also occurs at the vinyl group. The dual crosslinking reaction together results in the trinuclear tin complex photoresist having extremely high sensitivity. Attached Figure Description

[0039] Figure 1 The crystal structure of the compound prepared in Example 1 of this invention;

[0040] Figure 2 The hydrogen nuclear magnetic resonance spectrum of the compound prepared in Example 1 of this invention;

[0041] Figure 3 The Fourier transform infrared spectrum of the compound prepared in Example 1 of this invention;

[0042] Figure 4 MALDI-TOF mass spectra of the compounds prepared in Example 1 of this invention;

[0043] Figure 5 The hydrogen nuclear magnetic resonance spectrum of the compound prepared in Example 2 of this invention;

[0044] Figure 6 The Fourier transform infrared spectrum of the compound prepared in Example 2 of this invention;

[0045] Figure 7 MALDI-TOF mass spectra of the compounds prepared in Example 2 of this invention;

[0046] Figure 8 The crystal structure of the compound prepared in Example 3 of this invention;

[0047] Figure 9 The hydrogen nuclear magnetic resonance spectrum of the compound prepared in Example 3 of this invention;

[0048] Figure 10 The Fourier transform infrared spectrum of the compound prepared in Example 3 of this invention;

[0049] Figure 11 MALDI-TOF mass spectra of the compounds prepared in Example 3 of this invention;

[0050] Figure 12 The hydrogen nuclear magnetic resonance spectrum of the compound prepared in Example 4 of this invention;

[0051] Figure 13 The Fourier transform infrared spectrum of the compound prepared in Example 4 of this invention;

[0052] Figure 14 MALDI-TOF mass spectra of the compounds prepared in Example 4 of this invention;

[0053] Figure 15 The images are SEM images of the compounds prepared in Examples 1, 2, 3, 4, 5, and 6 of this invention under EBL.

[0054] Figure 16 The contrast curves of the compounds prepared in Examples 1, 2, 3, 4, 5, and 6 of this invention under EBL are shown.

[0055] Figure 17 The images show SEM images of periodic lines formed by preparing thin films from solutions of the compounds prepared in Examples 1, 2, 3, 4, 5, and 6 of this invention under EBL.

[0056] Figure 18 The SEM images of periodic lines formed by preparing thin films from solutions of the compounds prepared in Examples 1, 2, 3, and 4 of this invention under EUVL conditions. Detailed Implementation

[0057] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0058] Example 1

[0059]

[0060] 1.6083 g of dihydroxydibutyltin and 1.2611 g of 5-methylisophthalic acid were added to a 100 mL round-bottom flask, followed by 60 mL of anhydrous methanol. The flask was fitted with a reflux condenser and reacted at 66 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, then filtered, washed three times with diethyl ether, and the resulting solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain a dried solid product, named Me-Sn-Bu.

[0061] The solid powder was dissolved in chloroform, and crystals were obtained by evaporation of diethyl ether at room temperature. The crystal structure is shown below. Figure 1 .

[0062] Crystal data: Space Group: P-1, Cell: a=13.9589(4)b=14.0757(5)c=15.3213(4), alpha=97.470(2)beta=109.093(2)gamma=95.510(3).

[0063] 1¹H NMR (400MHz, Chloroform-d): δ 8.86 (s, 3H), 8.16 (s, 6H), 2.48 (s, 9H), 1.82–1.71 (m, 24H), 1.43–1.38 (m, 12H), 0.88 (t, J = 7.3Hz, 18H). See details... Figure 2 .

[0064] FTIR(KBr, cm -1 ): v(=CH)3080, v(CH)2958, 2927, 2867; vas(C=O)1712;

[0065] v(C=C)1621,1573; γ(CH)1354; -(CH2)n-746; v(Sn-O)460. See details. Figure 3 .

[0066] MALDI-TOF mass spectrometry analysis (m / z): [C 51 H 72 O 12 Sn3+H] + Theoretical value: 1237.2162; Measured value: 1237.2211, [C 51 H 72 O 12 Sn3+Na] + Theoretical value: 1259.1982; Measured value: 1259.2010. [C] 51 H 72 O 12 Sn3+K] + Theoretical value: 1275.1721, measured value: 1275.1785. See details. Figure 4 .

[0067] Example 2

[0068]

[0069] 2.2804 g of dihydroxydioctyltin and 1.2611 g of 5-methylisophthalic acid were added to a 100 mL round-bottom flask, followed by 70 mL of anhydrous methanol. The flask was fitted with a reflux condenser and reacted at 66 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, then filtered and washed three times with diethyl ether. The resulting solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain a dried solid product, named Me-Sn-Oc.

[0070] 1¹H NMR (400MHz, Chloroform-d): δ 8.86 (s, 3H), 8.15 (s, 6H), 2.48 (s, 9H), 1.77 (t, J = 6.6Hz, 12H), 1.39–1.16 (m, 72H), 0.82 (t, J = 6.5Hz, 18H). See details... Figure 5 .

[0071] FTIR (KBr, cm-1): v(=CH)3086, v(CH)2956, 2923, 2852; vas(C=O)1715;

[0072] v(C=C)1612,1561; γ(CH)1351; -(CH2)n-771,755; v(Sn-O)477. See details. Figure 6 .

[0073] MALDI-TOF mass spectrometry analysis (m / z): [C 75 H 120 O 12 Sn3+Na] + Theoretical value: 1595.5738; Measured value: 1595.5722. [C] 75 H 120 O 12 Sn 3 +K] + Theoretical value: 1611.5477. Measured value: 1611.5492. See details. Figure 7 .

[0074] Example 3

[0075]

[0076] 0.2681 g of dihydroxydibutyltin and 0.1922 g of 5-vinylisophthalic acid were added to a 25 mL round-bottom flask, followed by 10 mL of anhydrous methanol. The flask was fitted with a reflux condenser and reacted at 66 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, then filtered, washed three times with diethyl ether, and the resulting solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain the dried solid product, named Vi-Sn-Bu.

[0077] Crystal data: Space Group: P-1, Cell: a=13.8392(4)b=14.2254(4)c=16.1851(5), alpha=108.474(3)beta=94.418(3)gamma=101.900(3).

[0078] The solid powder was dissolved in chloroform, and crystals were obtained by evaporation of diethyl ether at room temperature. The crystal structure is shown below. Figure 8 .

[0079] 1 H NMR (400MHz, Chloroform-d): δ8.93(s,3H),8.37(d,J=1.6Hz,6H),6.81(dd,J=17.6,10.9Hz,3H),5.97(d, J=17.6Hz,3H),5.42(d,J=10.9Hz,3H),1.91–1.70(m,24H),1.41(q,J=7.3Hz,12H),0.89(t,J=7.3Hz,18H). For details, see Figure 9 .

[0080] FTIR (KBr, cm-1): v(=CH)3089, v(CH)2957, 2927, 2871; vas(C=O)1700;

[0081] v(C=C)1614,1562; γ(CH)1347; -(CH2)n-777,755; v(Sn-O)478. See details. Figure 10 .

[0082] MALDI-TOF mass spectrometry analysis (m / z): [C 54 H 72 O 12 Sn3+Na] + Theoretical value: 1295.1982, measured value: 1295.1928. [C] 54 H 72 O 12 Sn3+K] + Theoretical value: 1311.1721, measured value: 1311.1772. See details. Figure 11 .

[0083] Example 4

[0084]

[0085] 0.3421 g of dihydroxydioctyltin and 0.1922 g of 5-vinylisophthalic acid were added to a 50 mL round-bottom flask, followed by 20 mL of anhydrous methanol. The flask was fitted with a reflux condenser and reacted at 66 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, then filtered, washed three times with diethyl ether, and the resulting solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain the dried solid product, named Vi-Sn-Oc.

[0086] 1 ¹H NMR (400MHz, Chloroform-d): δ 8.93 (s, 3H), 8.37 (d, J = 1.6 Hz, 6H), 6.81 (dd, J = 17.6, 10.9 Hz, 3H), 5.97 (d, J = 17.6 Hz, 3H), 5.42 (d, J = 10.9 Hz, 3H), 1.81–1.75 (m, 12H), 1.40–1.12 (m, 72H), 0.83–0.77 (m, 18H). See details... Figure 12 .

[0087] FTIR (KBr, cm-1): v(=CH)3090, v(CH)2956, 2925, 2853; vas(C=O)1704;

[0088] v(C=C)1605, 1561; γ(CH)1350; -(CH2)n-777, 755; v(Sn-O)476. See details. Figure 13 .

[0089] MALDI-TOF mass spectrometry analysis (m / z): [C 78 H 120 O 12 Sn3+Na] + Theoretical value: 1631.5738, measured value: 1631.5678. [C] 78 H 120 O 12 Sn3+K] + Theoretical value: 1647.5477, measured value: 1647.5530. See details. Figure 14 .

[0090] Example 5

[0091]

[0092] 2.5 g of dibutyltin oxide and 2.421 g of 5-phenylisophthalic acid were added to a 250 ml round-bottom flask. 120 ml of a toluene:ethanol mixture (5:1) was added, and a Dean-Starck apparatus and condenser were installed. The mixture was reacted at 108 °C for 12 h. After the reaction was complete, the insoluble matter was removed by hot filtration. The filtered liquid was then removed by vacuum rotary evaporation to remove the solvent mixture. The solid product obtained by rotary evaporation was washed with n-hexane and filtered. The filtered solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain the dried solid product, named Ph-Sn-Bu.

[0093] Example 6

[0094]

[0095] 3.622 g of dioctyltin oxide and 2.421 g of 5-phenylisophthalic acid were added to a 250 mL round-bottom flask. 120 mL of a toluene:ethanol mixture (5:1) was added, and a Dean-Starck apparatus with a condenser was installed. The mixture was reacted at 108 °C for 12 h. After the reaction was complete, the insoluble matter was removed by hot filtration. The filtered liquid was then removed by vacuum rotary evaporation to remove the solvent mixture. The solid product obtained by rotary evaporation was washed with n-hexane and filtered. The filtered solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain a dried solid product, named Ph-Sn-Oc.

[0096] Examples 1-6

[0097]

[0098] Comparative Example 1

[0099]

[0100] 1.84 g of dihydroxydimethyltin and 1.8 g of 5-methylisophthalic acid were added to a 100 mL round-bottom flask, followed by 70 mL of anhydrous methanol. The flask was fitted with a reflux condenser and reacted at 66 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, then filtered and washed three times with diethyl ether. The resulting solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain a dried solid product, named Me-Sn-Me.

[0101] Comparative Example 2

[0102]

[0103] 0.1656 g of dihydroxydimethyltin and 0.1922 g of 5-vinylisophthalic acid were added to a 25 mL round-bottom flask, followed by 10 mL of anhydrous methanol. The flask was fitted with a reflux condenser and reacted at 66 °C for 24 h. After the reaction was complete, the mixture was allowed to cool naturally, then filtered, washed three times with diethyl ether, and the resulting solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain the dried solid product, named Vi-Sn-Me.

[0104] Comparative Example 3

[0105]

[0106] 1.6590 g of dimethyltin oxide and 2.421 g of 5-phenylisophthalic acid were added to a 250 mL round-bottom flask. 120 mL of a toluene:ethanol mixture (5:1) was added, and a Dean-Starck apparatus with a condenser was installed. The mixture was reacted at 108 °C for 12 h. After the reaction was complete, the insoluble matter was removed by hot filtration. The filtered liquid was then removed by vacuum rotary evaporation to remove the solvent mixture. The solid product obtained by rotary evaporation was washed with n-hexane and filtered. The filtered solid was placed in a vacuum drying oven and dried under vacuum at 45 °C for 48 h to obtain a dried solid product, named Ph-Sn-Me.

[0107] Comparative Examples 1-3

[0108]

[0109] Application examples

[0110] Applications of a class of trinuclear tin complexes in extreme ultraviolet lithography and electron beam lithography:

[0111] 10 mg of the trinuclear tin complexes prepared in Examples 1, 2, 3, 4, 5, and 6 were accurately weighed using a 0.01 g / mL balance and added to 1 mL of chloroform solution. The solutions were ultrasonically vibrated for 30 min and then filtered twice through a 0.22 μm PTFE membrane to obtain photoresist solutions. For spin coating, 50 μL of the photoresist solution was dropped onto a 1 cm x 1 cm silicon wafer using a pipette. The wafer was rotated at 9000 rpm for 30 s and then baked at 66 °C for 1 min to obtain a smooth film with a thickness of approximately 20-30 nm.

[0112] Test Example 1

[0113] 10 mg of the trinuclear tin complexes prepared in Comparative Examples 1, 2, and 3 were accurately weighed using a 0.01 g / mL balance and added to dozens of common solvents, including methanol, ethanol, isopropanol, PGMEA, ethyl acetate, butyl acetate, chloroform, dichloromethane, cyclohexanone, 2-heptanone, acetone, diethyl ether, and toluene. After ultrasonic agitation for 60 min, none of the solutions dissolved. This indicates that Comparative Examples 1, 2, and 3 are virtually insoluble in all common solvents.

[0114] Test Example 2

[0115] Thin films prepared from the compounds provided in Examples 1, 2, 3, 4, 5, and 6 using the method described in the application examples were subjected to normalized electron beam exposure tests. The accelerating voltage was 30 kV, and each cube was 5 μm x 5 μm in size with a spacing of 3 μm, for a total of 8 x 8 = 64 cubes. After exposure, the films were baked at 100 °C for 1.5 min, and then developed in methanol, 2-heptanone, MIBK, DMF, IPA, and methanol for 60 s, respectively. After further development at 100 °C, the films were baked for 30 s. Electron micrographs of the six trinuclear tin complexes were obtained using SEM, as shown below. Figure 15 Then, the height of each small square was measured using AFM, normalized, and a contrast curve was plotted with the corresponding dose. See details below. Figure 16 The contrast ratio is calculated using the following formula:

[0116]

[0117] The contrast ratios of the compounds prepared in the above examples were calculated and are shown in Table 1. The electron beam exposure sensitivity (DL) of the compounds prepared in the above examples is also shown. 0.5 As shown in Table 2.

[0118] Table 1. Contrast of the compounds in the above embodiments

[0119] Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Contrast 0.858 1.2851 1.6264 1.0167 0.809 1.2044

[0120] Table 2. Sensitivity of the compounds in the above examples.

[0121] Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 <![CDATA[D 0.5 (μC / cm 2 )]]> 570 170 235 60 400 250

[0122] Combination Figure 16 As shown in Table 1, the contrast ratios of Examples 2, 3, and 4 are between 1 and 2, which is suitable for currently available commercial photoresists. They are also suitable for obtaining more vertical lines on the sidewalls during the periodic line patterning process.

[0123] Based on Table 2 and the molecular structures of the above embodiments, it can be seen that the exposure sensitivity of the trinuclear tin complex gradually increases with the growth of the alkane carbon chain connected to the Sn nucleus. From a bond energy perspective, it can be observed that as the alkane carbon chain connected to the Sn nucleus grows, the energy required to break the Sn-C bond gradually decreases, and it becomes easier to generate alkyl radicals, thereby initiating a series of other photochemical reactions, thus gradually increasing the sensitivity. Secondly, introducing other unstable ligands or ligands that can also undergo photochemical reactions during exposure onto isophthalic acid can further improve the exposure sensitivity. From a reaction mechanism perspective, the ligands introduced onto isophthalic acid can initiate a new photochemical reaction pathway. Compared with photochemical reactions occurring solely near the Sn nucleus, multiple photochemical reaction pathways occur simultaneously, which is beneficial for improving quantum utilization efficiency, increasing photochemical reactivity, and thus increasing exposure sensitivity.

[0124] Combination Figure 16 As shown in Table 2, the trinuclear tin complexes provided by this invention all have high sensitivity, which is higher than that of most publicly disclosed photoresists. This is beneficial to improving the efficiency of photon utilization. Moreover, high sensitivity means that less energy is required during exposure, which is beneficial to improving energy utilization efficiency and realizing industrialization.

[0125] Test Example 3

[0126] Thin films made from the trinuclear tin complexes provided in Examples 1, 2, 3, 4, 5, and 6 using the method described in the application examples were subjected to electron beam exposure. The accelerating voltage for electron beam exposure was 30 kV. After exposure, the films were baked at 100°C for 1.5 min, then developed in methanol, 2-heptanone, MIBK, DMF, IPA, and methanol for 60 s, respectively, followed by further development at 100°C and baking for 30 s. The periodically patterned SEM results of the above trinuclear tin complexes after development are shown below. Figure 17 .

[0127] Combination Figure 17 As can be seen, the compound (Me-Sn-Bu) shown in Example 1 formed a linewidth of approximately 19 nm under a 100 nm period; the compound (Me-Sn-Oc) shown in Example 2 formed a linewidth of approximately 21 nm under a 100 nm period; the compound (Vi-Sn-Bu) shown in Example 3 formed a linewidth of approximately 30 nm under a 100 nm period; the compound (Vi-Sn-Oc) shown in Example 4 formed a linewidth of approximately 20 nm under a 100 nm period; the compound (Ph-Sn-Bu) shown in Example 5 formed a linewidth of approximately 30 nm under a 100 nm period; and the compound (Ph-Sn-Oc) shown in Example 6 formed a linewidth of approximately 20 nm under a 100 nm period.

[0128] Test Example 4

[0129] Thin films prepared from the compounds provided in Examples 1, 2, 3, and 4 using the method described in the application examples were patterned at the Shanghai Synchrotron Radiation Facility (SSRF) using X-ray Interference Lithography (XIL) under EUV (13.5 nm) exposure. After EUV exposure, they were baked at 100°C for 1.5 min, developed in methanol, 2-heptanone, MIBK, and DMF for 60 s respectively, and then developed at 100°C and baked for 30 s.

[0130] During extreme ultraviolet (EUV) exposure, a mask capable of forming L / S periodic lines with a half-pitch of 37.5 nm was used. After development, SEM was used for observation, and the test results are as follows: Figure 18 .

[0131] like Figure 18As shown, the compound (Me-Sn-Bu) shown in Example 1 at 150 mJ / cm 2 The following lines were formed with a linewidth of approximately 22 nm; the compound (Me-Sn-Oc) shown in Example 2 was tested at 150 mJ / cm². 2 Lines with a linewidth of approximately 30 nm were formed; the compound (Vi-Sn-Bu) shown in Example 3 was tested at 180 mJ / cm². 2 Lines with a linewidth of approximately 20 nm were formed; the compound (Vi-Sn-Oc) shown in Example 4 was tested at 180 mJ / cm². 2 The resulting lines have a linewidth of approximately 25 nm. The test results show that as the alkane carbon chain connected to the Sn core grows, the energy required to break the Sn-C bond gradually decreases, leading to increased exposure sensitivity. However, this also results in a certain degree of reduced patterning resolution.

[0132] In summary, the tri-core tin complex photoresist provided by this invention has the beneficial effects of high resolution and extremely high sensitivity.

[0133] When evaluating the performance of the photoresist molecules of this invention, conventional photoresist molecules with similar structures were used as a benchmark (see the Background section). Through precise comparative analysis, the significant enhancement in sensitivity of the embodiments of this invention was quantified. This key performance indicator is directly related to the efficiency and resolution in the photolithography process.

[0134] Specifically, compared with the reference sample, different embodiments of the present invention exhibit varying degrees of sensitivity improvement, with values ​​of approximately 233%, 1018%, 709%, 3067%, 375%, and 660%, respectively. These data not only confirm the breakthrough progress of the present invention in the field of photoresist technology, but also intuitively demonstrate its substantial leap in improving photolithography performance.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A class of trinuclear tin complexes, characterized in that: The trinuclear tin complex has the following structure of general formula I: In general formula I, R1 is selected from straight-chain alkyl groups having 4-10 carbons; R2 is selected from an alkenyl group having 2-6 carbons.

2. A class of trinuclear tin complexes, characterized in that: The trinuclear tin complex has the following structure of general formula I: In general formula I, R1 is selected from n-butyl or n-octyl; R2 is selected from methyl, vinyl or phenyl.

3. The method for synthesizing a type of trinuclear tin complex according to claim 1 or 2, characterized in that: Includes the following steps: Tin cores modified with R1 substituents are reacted with isophthalic acid modified with R2 substituents in a solvent at a molar ratio of 1:1~2. After the reaction is completed, the mixture is cooled, filtered, washed, solvent removed, and vacuum dried to obtain a solid product. The mass-volume ratio of the mixture of dihydroxytin or tin oxide modified with R1 substituents and isophthalic acid modified with R2 substituents to the solvent is 1 g: 15~25 ml. The tin core modified with the R1 substituent is or ; The isophthalic acid modified with the R2 substituent is .

4. The method for synthesizing a type of trinuclear tin complex according to claim 3, characterized in that: The reaction includes: using anhydrous methanol as a solvent, reacting at 64.7~70℃ for 20~24h; or using a mixed solvent of toluene:ethanol at a volume ratio of 4~6:1 and a Dean-Starck apparatus, reacting at 105~110℃ for 8~12h.

5. The method for synthesizing a type of trinuclear tin complex according to claim 3, characterized in that: Dihydroxytin modified with R1 substituent and isophthalic acid modified with R2 substituent were reacted in anhydrous methanol at a molar ratio of 1:1~2. The reaction temperature was 64.7~70℃ and the reaction time was 20~24h. After the reaction was completed, the product was cooled, filtered, washed and dried under vacuum to obtain a solid product. The reaction formula is as follows: 。 6. The method for synthesizing a type of trinuclear tin complex according to claim 3, characterized in that: Tin oxide modified with R1 substituent and isophthalic acid modified with R2 substituent were reacted in a mixture of toluene and ethanol at a molar ratio of 1:1 to 2 and a volume ratio of 4 to 6:

1. The reaction vessel was a Dean-Starck apparatus with a condenser. The reaction temperature was 105 to 110 °C and the reaction time was 8 to 12 h. After the reaction was completed, the insoluble matter was removed by hot filtration and the solvent mixture was removed by vacuum rotary evaporation. The obtained solid product was washed, filtered, and vacuum dried to obtain a pure solid product. The reaction formula is as follows: 。 7. The application of a type of trinuclear tin complex as described in claim 1 or 2 in extreme ultraviolet lithography and electron beam lithography, wherein the trinuclear tin complex is used as a photosensitizer and resin in a photoresist formulation.

8. The application according to claim 7, characterized in that: The photoresist is prepared by the following method: chloroform is added to the trinuclear tin complex at a ratio of 10~20mg:1~2ml, and the mixture is ultrasonically treated for 10~30min and then filtered to obtain the photoresist solution.

9. The application according to claim 7, characterized in that: The trinuclear tin complex, as a photosensitizer and resin in an electron beam photoresist formulation, enables the patterning of 19-30 nm linewidth lines with high sensitivity in electron beam lithography; or, the trinuclear tin complex, as a photosensitizer and resin in an extreme ultraviolet (EUV) photoresist formulation, enables the patterning of 20-30 nm linewidths at a 50-100 nm period in EUV lithography exposure.

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