Methods for post-processing dielectric membranes with microwave radiation

Abstract

A method for post-processing a dielectric film formed on the surface of a substrate includes the step of positioning the substrate on which the dielectric film is formed in a processing chamber, and the step of exposing the dielectric film in the processing chamber to microwave radiation of a frequency of 5 GHz to 7 GHz.

Description

Technology Field

[0001] The embodiments of the present disclosure generally relate to dielectric films and processes for fabricating dielectric films, and more specifically, to post-processing dielectric films with microwave radiation. Background Technology

[0002] In the fabrication of miniaturized semiconductor devices including STI (shallow trench isolation), IMD (inter-metal dielectric) layers, ILD (inter-layer dielectric) layers, PMD (pre-metal dielectric) layers, passivation layers, etc., it is necessary to fill gaps with high aspect ratios with insulating materials. As the feature sizes of transistors and the spaces between them are reduced to 20 nm or less and thermal budgets decrease, void-free filling of such fine, high aspect ratio features is becoming increasingly difficult. In fluidized chemical vapor deposition (CVD), a liquid phase dielectric precursor is delivered into gaps and trenches on a substrate and then cured into a solid phase dielectric film (referred to as a fluidized film, fluidized CVD dielectric film, or gap-filled film) by steam annealing, UV (ultraviolet) irradiation, high-temperature pressing, and sintering at high temperatures. In many cases, such solidification processes provide thermal energy to the dielectric precursor, causing the dielectric film to solidify prematurely (consequently causing shrinkage of the dielectric film and / or forming seams and voids in the dielectric film), and / or oxidizing the underlying metals of the substrate by heated steam. Furthermore, solidification processes caused by thermal energy cause non-uniformity in the thickness direction of the dielectric film and can only process near the surface of the dielectric film. Therefore, to ensure void-free filling of gaps and trenches under low thermal budget requirements, a new solidification process is required to form soft gap-filling dielectric films with low modulus and viscosity.

[0003] Furthermore, dielectric films are needed that have improved mechanical properties compared to thermal oxide films, such as an improved WERR (wet etch rate) (less than 2:1), a dielectric constant lower than that of thermal oxide films, and low internal stress.

[0004] The embodiments described herein generally relate to a method for post-processing a dielectric film formed on the surface of a substrate, the method comprising the steps of positioning the substrate on which the dielectric film is formed in a processing chamber, and exposing the dielectric film in the processing chamber to microwave radiation of a frequency of 5 GHz to 7 GHz.

[0005] Embodiments of the present disclosure further provide a method for forming and post-processing a dielectric film on the surface of a substrate, the method comprising the steps of delivering a dielectric precursor onto a substrate disposed in a processing zone of a first chamber, delivering a radical flux to the processing zone of the first chamber, and exposing the delivered dielectric precursor to microwave radiation of a frequency of 5 GHz to 7 GHz. Brief explanation of the drawing

[0006] In a manner that the features listed above of the present disclosure can be understood in detail, a more specific description of the present disclosure, which has been briefly summarized above, may be made with reference to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of the present disclosure and should not be construed as limiting the scope of the present disclosure, as the present disclosure may allow for other equally valid embodiments.

[0007] FIG. 1 is a flowchart illustrating a method for forming a dielectric film according to one embodiment.

[0008] FIG. 2 is a schematic diagram of a system of processing chambers according to one embodiment.

[0009] FIG. 3a is a schematic side cross-sectional view of a deposition chamber according to one embodiment.

[0010] FIG. 3b is a schematic bottom view of a shower head according to one embodiment.

[0011] FIG. 4 is a schematic diagram of a microwave exposure chamber according to one embodiment.

[0012] FIGS. 5A, 5B, and 5C illustrate Fourier-Transform infrared (FTIR) spectra, leakage current, and reflective index / shrinkage of a fluid membrane according to one embodiment.

[0013] FIGS. 6c, FIGS. 6d, FIGS. 6e, FIGS. 6f, FIGS. 6g, FIGS. 6h, FIGS. 6i, and FIGS. 6j illustrate FTIR spectra and leakage current of a fluid film according to one embodiment.

[0014] FIGS. 7a, 7b, and 7c illustrate FTIR spectra, WERR (wet etch rate), and reflectance / shrinkage rate of a fluid film according to one embodiment.

[0015] For clarity, the same reference numerals have been used where applicable to designate identical elements common to the drawings. Additionally, the elements of one embodiment may be advantageously configured for use in other embodiments described herein. Specific details for implementing the invention

[0016] The embodiments described herein provide methods for post-processing a dielectric film formed on a substrate, for example by fluid CVD. The dielectric film may be a low-k SiCOH-based film containing silicon-carbon-oxygen (Si-CO) bonds, a SiCON-based film containing silicon-carbon-and-hydrogen (Si-CH) bonds, or a SiO-based film. The dielectric film as deposited on the substrate contains a large amount of hydroxyl groups (-OH) that can cause aging (i.e., moisture absorption) and reduce the densities and strength of the film. The methods described herein include the step of post-processing a dielectric film formed on the surface of a substrate, the step of positioning the substrate on which the dielectric film is formed in a processing chamber, and the step of exposing the dielectric film in the processing chamber to microwave radiation at a frequency of 5 GHz to 7 GHz. The methods described herein can be used to reduce or remove the amount of hydroxyl groups (-OH) in dielectric films formed by exposure to microwave radiation, while preventing shrinkage of dielectric films due to thermal convection.

[0017] The embodiments described herein also include dielectric films (e.g., SiCOH, SiO₂) by fluid CVD to fill gaps having a high aspect ratio (AR) and small dimensions (e.g., AR ≥ 8). x , SiC, SiCO, SiCON, SiCN, SiN xMethods for forming ) are provided. In some embodiments, dielectric films formed by fluid CVD are seam-free and can fill high AR trenches. In some embodiments, dielectric films containing a high carbon content can be used in hard mask and low-k fluid applications. In some embodiments, dielectric films are deposited using a liquid dielectric precursor and co-reactants of radical forms (reactive gases), such as oxygen (O2) or ammonia (NH3).

[0018] FIG. 1 is a flowchart illustrating a method (100) used to form a dielectric film on the surface of a substrate according to one embodiment.

[0019] In block (102), a substrate is provided in a deposition chamber. The substrate may be, for example, a metal substrate, such as aluminum or stainless steel; a semiconductor substrate, such as silicon, SOI (silicon-on-insulator), or gallium arsenide; a glass substrate; or a plastic substrate. The semiconductor substrate may be a substrate patterned at any manufacturing / fabrication stage in the formation of integrated circuits. The patterned substrate may include gaps, trenches, holes, vias, etc., to be filled with a dielectric material.

[0020] In block (104), one or more liquid dielectric precursors and a carrier gas, such as argon (Ar) or helium (He), are flowed into the deposition chamber through a gas delivery device such as a DCSH (dual channel showerhead) so that the dielectric precursor is delivered onto the surface of a substrate placed in the deposition chamber at a flow rate of about 250 sccm to about 5000 sccm per channel of the DCSH. The surface of the substrate may be held at a reduced temperature of about 40°C to about 150°C, for example, about 80°C. The pressure in the deposition chamber may be maintained at about 0.5 Torr to about 3.0 Torr.

[0021] In some embodiments, the dielectric precursor is an organosilicon compound comprising silicon, carbon, and hydrogen, such as silane, disilane, methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, tetraethoxysilane (TEOS), triethoxysilane (TES), octamethylcyclotetrasiloxane (OMCTS), tetramethyl-disiloxane (TMDSO), tetramethylcyclotetrasiloxane (TMCTS), tetramethyl-diethoxy-disiloxane (TMDDSO), dimethyl-dimethoxy-silane (DMDMS), or a combination thereof. In some embodiments, the dielectric precursor is an organosilicon compound comprising silicon, nitrogen, hydrogen, and chlorine, such as silylamines and their derivatives—including trisilylamine (TSA) and disilylamine (DSA)—an organosilicon compound comprising silicon, nitrogen, hydrogen, and oxygen, or a combination thereof.

[0022] In block (106), plasma may be generated outside the deposition chamber and flow into the processing zone of the deposition chamber along with a carrier gas (e.g., Ar, He) (remote plasma) or may be generated inside the deposition chamber (direct plasma). Plasma may be generated by the dissociation of a processing precursor gas comprising molecular oxygen (O2), ozone (O3), molecular hydrogen (H2), nitrogen-hydrogen compounds (e.g., NH3, N2H4), nitrogen-oxygen compounds (e.g., NO, NO2, N2O), hydrogen-oxygen compounds (e.g., H2O, H2O2), nitrogen-hydrogen-oxygen compounds (e.g., NH4OH), carbon-oxygen compounds (CO, CO2), or a combination thereof. In the chamber plasma zone, O * , H * , and / or N * - Containing radicals, such as O * , H * , N * , NH3 * , N2H4 * , NH2 * , NH * , N * O *, C3H6 * , C2H2 * , or a combination of these can be activated.

[0023] In some embodiments, activated radicals (referred to as "radical flux") from a plasma generated from a remote plasma source (RPS) outside the deposition chamber flow into the deposition chamber at a flow rate of about 1 sccm to about 10,000 sccm.

[0024] In some embodiments, plasma may be generated within a deposition chamber from a capacitively coupled plasma (CCP) source driven by a radio-frequency (RF) power supply. One of the two electrodes is connected to the power supply and the other is grounded. In some embodiments, a mesh is placed between the CCP source and the substrate within the deposition chamber to prevent the delivered dielectric precursor from being struck by the plasma.

[0025] In block (108), one or more radicals (also referred to as reactive gases) within the processing zone react with the delivered dielectric precursor to form a dielectric film. The composition of the formed dielectric film can be adjusted by changing the composition of the reactive gas within the radical flux. To form oxygen-containing films, such as SiO, SiC, SiOC, SiON, and SiCON, the reactive gas may be, for example, oxygen (O2), ozone (O3), or water (H2O). To form nitrogen-containing films, such as SiON, SiCON, and SiN films, the reactive gas may be, for example, ammonia (NH3), hydrazine (N2H4), nitrogen dioxide (NO2), or nitrogen (N2). To form carbon-containing films, the reactive gas may be, for example, propylene (C3H6) or acetylene (C2H2).

[0026] When oxygen (O2) radicals in the processing zone react with the transferred dielectric precursor, the transferred dielectric precursor becomes hydrophilized (i.e., hydroxyl groups (-OH) are attached to the organosilicon compounds). That is, the oxygen (O2) radicals in the deposition chamber cause the methyl groups (R(-CH3)) in the organosilicon compounds within the transferred dielectric precursor to be replaced by hydroxyl groups (-OH), thereby forming silanol groups (Si-OH).

[0027] In block (110), the formed dielectric film is cured by exposure to microwave radiation in a microwave exposure chamber, causing cross-linking between compounds having hydroxyl groups (-OH) in the dielectric precursor to form a cured film. That is, when the silanol groups (Si-OH) of adjacent compounds in the formed dielectric film react, the adjacent compounds are cross-linked by removing the hydroxyl groups (-OH), forming siloxane functional groups (Si-O-Si), and producing water (H2O).

[0028] The removal of these hydroxyl groups (-OH) can reduce the effects of aging and increase the densities and strengths of the cured film by reducing or eliminating seams and voids that lead to leakage currents. Furthermore, the removal of hydroxyl groups (-OH) can lower the dielectric constant of the film, as required by many device applications.

[0029] Without being bound by theory, microwave radiation is believed to non-thermally activate the vibrational motions of hydroxyl groups (-OH) within dielectric films, thereby breaking OH bonds and reducing or removing silanol groups (Si-OH). Unlike UV irradiation or thermal annealing, which inevitably provide thermal energy to the dielectric film causing it to solidify prematurely (and consequently shrink the cured film) and / or oxidize the underlying metals within the substrate by heated steam, this treatment is non-thermal. In microwave radiation treatment, low substrate temperatures can be maintained throughout the microwave radiation process to meet the low thermal budget requirements of many applications, and consequently, dielectric precursors maintain fluidity, ductility, and malleability.

[0030] In treatment by microwave radiation, microwave frequencies vary from about 5 GHz to 7 GHz, e.g., 5.8 GHz. The density and thickness of the cured film after exposure to microwave radiation change as the microwave frequencies change.

[0031] The microwave power and exposure time required to remove hydroxyl groups (-OH) are correlated (i.e., higher power requires shorter exposure times). The microwave power density is approximately 0.7 W / cm². 2 Up to 7.0 W / cm 2The microwave exposure times may be in the range of less than about 1 minute to about 120 minutes, e.g., about 1 minute to about 20 minutes, or about 5 minutes to about 10 minutes. As desired, to remove hydroxyl groups (-OH) from the cured film, increase density, and lower the dielectric constant, the microwave power must be sufficiently high and the exposure time sufficiently long. However, reduced exposure time due to higher microwave power may reduce process time in commercial applications.

[0032] During exposure to microwave radiation, the substrate may be placed on a substrate pedestal (shown in FIG. 4) maintained at room temperature, and the substrate temperature may be in the range of room temperature to about 450°C. The use of microwave radiation enables lower thermal budgets than thermal annealing because heat is not transferred by thermal convection. In some embodiments, the substrate pedestal is connected to a heater to adjust the temperature of the substrate.

[0033] The pressure during microwave radiation is in the range of 0.01 to 760 Torr (atmospheric pressure), e.g., atmospheric pressure. Microwave radiation is generated in an inert environment containing an inert gas, e.g., helium or argon, within a microwave exposure chamber. In some embodiments, microwave exposure is performed in an ambient gas containing oxygen, air, or water vapor. In other embodiments, a reactive gas environment such as H2, N2, NH3, CO2, or CO is used.

[0034] Microwave radiation can be applied continuously or in a pulsed form. In some embodiments, microwave radiation is applied in a TE (transverse electric) and / or TM (transverse magnetic) mode.

[0035] Examples of deposition systems can be integrated into larger fabrication systems for producing integrated circuit chips. FIG. 2 illustrates one such system (1001) comprising processing chambers (1008a-1008f) according to one embodiment. In FIG. 2, a pair of front opening unified pods (FOUPs) (1002) supply substrates (e.g., wafers with a diameter of 300 mm) that are received by robot arms (1004) and placed in a low-pressure holding area (1006). A second robot arm (1010) may be used to transfer the substrate between the low-pressure holding area (1006) and the processing chambers (1008a-1008f).

[0036] Processing chambers (1008a-1008f) may include one or more system components for depositing a dielectric film on a substrate. In some embodiments, a pair of processing chambers (e.g., 1008a-1008b) may be used as deposition chambers for delivering a dielectric precursor onto a substrate. Accordingly, in some embodiments, the system (1001) is configured to perform the method (100) by performing blocks (102-108) of the method (100) on a substrate positioned in a pair of processing chambers (e.g., 1008a-1008b) and delivering the substrate to a microwave exposure chamber located outside the system (1001), wherein block (110) is performed on the substrate.

[0037] The system (1001) further comprises a system controller (302) used to control the operation of the system (1001) and to implement the methods presented herein. The system controller (302) comprises a programmable central processing unit (in the present invention, a CPU (central processing unit) (304)) capable of operating with memory (306) (e.g., non-volatile memory) and support circuits (308). The support circuits (308) enable control of various components of the system (1001) by including caches, clock circuits, input / output subsystems, power supplies, and combinations thereof, which are coupled to the CPU (304) and coupled to various components of the system (1001). The CPU (304) is one of any type of general-purpose computer processor, such as a PLC (programmable logic controller), for controlling various components and sub-processors of the system (1001). The memory (306) coupled to the CPU (304) is a non-transient memory and is typically one or more of readily available memories, such as RAM (random access memory), ROM (read only memory), a floppy disk drive, a hard disk, or any other form of local or remote digital storage.

[0038] FIG. 3a is a schematic diagram of a processing chamber (1101) having a chamber body (1164) and a cover assembly (1165) according to one embodiment. The cover assembly (1165) generally includes a remote plasma source (RPS) (1110), a cover (1121), and a dual channel showerhead (DCSH) (1153). The remote plasma source (RPS) (1110) can process a processing precursor gas provided from a processing precursor gas source (1181). Then, the plasma formed in the RPS (1110) can be delivered into a chamber plasma zone (1120) through a gas inlet assembly (1111) and a baffle (1123) coupled to the cover (1121). A carrier gas (e.g., Ar, He) can be delivered into the chamber plasma zone (1120). The cover (1121), which is the uppermost conductive part, and the DCSH (dual channel showerhead) (1153) are positioned with an insulating ring (1124) in between, which allows AC potential to be applied to the cover (1121) relative to the DCSH (1153).

[0039] The DCSH (1153) is positioned between the chamber plasma zone (1120) and the substrate processing zone (1170), allowing radicals activated in the plasma present in the chamber plasma zone (1120) to pass into the substrate processing zone (1170) through a plurality of through-holes (1156). The flow of radicals (radical flux) is indicated by the solid arrow "A" in FIG. 3a. The substrate (1172) is placed on a substrate support (1173) positioned within the substrate processing zone (1170). The DCSH (1153) also has one or more hollow volumes (1151) that can be filled with a dielectric precursor provided from a precursor source (1182). The dielectric precursor is transferred from one or more hollow volumes (1151) to the substrate processing zone (1170) through small holes (1155), bypassing the chamber plasma zone (1120). The flow of the dielectric precursor is indicated by dashed arrows in FIG. 3a. An exhaust ring (1161) is used to uniformly evacuate the substrate processing zone (1170) by using an exhaust pump (1183). The DCSH (1153) may be thicker than the length of the minimum diameter of the through-holes (1156). The length of the minimum diameter (1150) of the through-holes may be limited by forming larger diameter portions of the through-holes (1156) that partially penetrate the DCSH (1153) to maintain the flow of radical flux from the chamber plasma zone (1120) into the substrate processing zone (1170). In some embodiments, the length of the minimum diameter of the through-holes (1156) may be equal to or less than the minimum diameter of the through-holes (1156).

[0040] In some embodiments, to deposit a dielectric precursor on a substrate, a pair of processing chambers of FIG. 2 (e.g., 1008c-1008d) (referred to as twin chambers) may be used. Each of the processing chambers (e.g., 1008c-1008d) may have the cross-sectional structure of the processing chamber (1101) depicted in FIG. 3a. The flow rates per channel of the DCSH described above correspond to the flow rates into each of the chambers (e.g., 1008c-1008d) through the corresponding DCSH (1153).

[0041] FIG. 3b is a schematic bottom view of a DCSH (1153) according to one embodiment. The DCSH (1153) can deliver radical flux and carrier gas present in the chamber plasma zone (1120) through through-holes (1156).

[0042] In some embodiments, the number of through-holes (1156) may be about 60 to about 2000. The through-holes (1156) may have round shapes or various shapes. In some embodiments, the minimum diameter of the through-holes (1156) may be about 0.5 mm to about 20 mm or about 1 mm to about 6 mm. The cross-sectional shape of the through-holes may be conical, cylindrical, or a combination of both shapes. In some embodiments, a plurality of small holes (1155) may be used to introduce a dielectric precursor into the substrate processing area (1170), the number of which may be about 100 to about 5000 or about 500 to about 2000. The diameter of the small holes (1155) may be about 0.1 mm to about 2 mm.

[0043] FIG. 4 is a schematic diagram of a microwave exposure chamber (401) according to one embodiment. The microwave exposure chamber (401) may be maintained under vacuum and / or may contain gases at pressures exceeding atmospheric pressure. A microwave source (403) is positioned outside the microwave exposure chamber (401).

[0044] The microwave exposure chamber (401) includes a substrate pedestal (405) that supports the substrate (407) in a position such that the substrate (407) can be irradiated by radiation from a microwave source (403). The substrate pedestal (405) may be rotatable and made of quartz. The microwave exposure chamber (401) may have a heater (not shown) for adjusting the temperature of the substrate (407). The microwave exposure chamber (401) includes a gas inlet (409) connected to a gas source (not shown) and a vacuum outlet (411) connected to a vacuum pump (not shown). The microwave exposure chamber (401) further includes valves and a mass flow controller (not shown) for adjusting the gas flow from the gas source into the microwave exposure chamber (401), and a pressure gauge (not shown) for measuring the pressure inside the microwave exposure chamber (401).

[0045] In the example illustrated in FIG. 4, the microwave source (403) is positioned outside the microwave exposure chamber (401). In some embodiments, the microwave source (403) is housed inside the microwave exposure chamber (401).

[0046] In block (110) of the method (100) described above, the microwave exposure chamber (401) is first vacuumed through the vacuum outlet (411), and then ambient gas, such as nitrogen, helium, argon, hydrogen, oxygen, air, or water vapor, is introduced through the gas inlet (409) to a specific chamber pressure or maintained under vacuum. Subsequently, the microwave source (403) is turned on to irradiate the substrate (407) with microwave radiation to cure the dielectric films. The microwave exposure chamber (401) may be at atmospheric pressure to remove any volatile residues or may be under continuous purging to remove any of the residual gases from the microwave exposure. Ambient gas is introduced again through the gas inlet (409), or the microwave exposure chamber (401) is maintained under vacuum. The microwave source (403) is turned on or kept on to further process the cured film for a desired duration to remove hydroxyl groups (-OH), and then the substrate (407) is removed from the microwave exposure chamber (401).

[0047] In the following, experimental measurements of exemplary dielectric membranes are provided to illustrate aspects of the embodiments of the present disclosure described herein. These examples are not intended to limit the scope of the present disclosure.

[0048] Example 1

[0049] A carbon-doped low-k SiCOH-based fluid dielectric film was formed on a substrate using an oxygen-containing plasma generated from a CCP source by the method (100) described above and an organic silicon compound containing silicon, carbon, hydrogen, and oxygen as a dielectric precursor.

[0050] The formed fluid film was then exposed to microwave radiation at 5.8 GHz in a nitrogen atmosphere at room temperature and atmospheric pressure. In Fig. 5a, the Fourier-Transform Infrared (FTIR) spectra of the fluid film are plotted for (i) immediately after delivery, (ii) after 10 minutes of exposure to microwave radiation at 30% of maximum power (1.6 kW), (iii) after 5 minutes of exposure to microwave radiation at 90% of maximum power, (iv) after 10 minutes of exposure to microwave radiation at 90% of maximum power, and (v) after 5 minutes of exposure to UV radiation at 385°C. 3400–3200 cm⁻¹ -1 The peaks in the range correspond to the vibrational frequencies of hydrogen-bonded silanol groups (Si-OH). Silanol groups (Si-OH) are at 950–810 cm⁻¹. -1 It shows absorption in the range of. As can be seen from Fig. 5a, the hydroxyl groups are completely removed after (iv) 10 minutes of exposure to microwave radiation at 90% of maximum power and (v) 5 minutes of exposure to UV radiation at 385°C.

[0051] As can be seen in Fig. 5b, exposure to microwave radiation is (i) 2.7 × 10 of the fluid membrane immediately after delivery -5 mA / cm 2 1.7 × 10 of the intermediate zone of the fluid membrane from -8 mA / cm 2As shown in Fig. 5c, not only does it reduce leakage current at an applied electric field of 2.0 mV / cm, but exposure to (v) UV radiation at 385°C for 5 minutes also reduces leakage current. As shown in Fig. 5c, removing hydroxyl groups also increases the density of the film, and thus the film shrinkage rate is about 3.4% after (iii) 5 minutes of exposure to microwave radiation at 90% of total power, and (iv) 10 minutes of exposure to microwave radiation at 90% of total power. However, this shrinkage rate is lower than the shrinkage rate of the dielectric fluid film cured by (v) UV radiation at 385°C for 5 minutes (about 6.4%). The decrease in reflectance was from 1.4221 to (iii) 1.3885 after 5 minutes, and (v) 1.3765 after 5 minutes of exposure to UV radiation at 385°C.

[0052] Example 2

[0053] A SiCON-based fluid film was formed on a substrate using an oxygen- and ammonia-containing plasma generated from an RPS source by the method (100) described above and a silicon-carbon- and hydrogen-containing organosilicon compound containing silicon, carbon, and hydrogen as dielectric precursors, wherein each carbon (C) is bonded to a pair of other carbon (C) atoms and hydrogen (H) atoms or two silicon (Si) atoms. The fluid film was further treated with O3 gas for oxidation. Then, the formed fluid film was exposed to microwave radiation of 5.8 GHz in a nitrogen atmosphere at atmospheric pressure at room temperature. In FIG. 6a, FTIR spectra of the fluid membrane are plotted at (i) immediately after delivery, (ii) after 10 minutes of exposure to microwave radiation at 30% of the maximum power (1.6 kW), (iii) after 5 minutes of exposure to microwave radiation at 90% of the maximum power, and (iv) after 10 minutes of exposure to microwave radiation at 90% of the maximum power. As can be confirmed from FIG. 6a, the 3400-3200 cm⁻¹ range corresponding to the vibration frequencies of the hydroxyl groups. -1 The peaks in the range of (iv) are completely eliminated after 10 minutes of exposure to microwave radiation at 90% of maximum power. After exposure to microwave radiation, 2280–2080 cm⁻¹, corresponding to the vibrational frequency of the Si-H groups, -1 The peaks in the range are also reduced.

[0054] As can be seen in Fig. 6b, exposure to microwave radiation is (i) 1.3 × 10 of the fluid membrane immediately after delivery -7 mA / cm 2 6.9 × 10 of the intermediate zone of the fluid membrane from -9 mA / cm 2 By, it reduces leakage current at an applied electric field of 2.0 mV / cm.

[0055] It is known that SiCON-based fluid films immediately after deposition absorb moisture, broadening peaks in FTIR spectra and degrading the electrical properties of the fluid film (referred to as aging). FIGS. 6c, FIGS. 6d, FIGS. 6e, FIGS. 6f, FIGS. 6g, FIGS. 6h, FIGS. 6i, and FIGS. 6j illustrate the FTIR spectra and leakage currents of the SiCON-based fluid films described above, before and after aging for 2 to 3 days. In the fluid films (i) immediately after delivery, (ii) after 10 minutes of exposure to microwave radiation at 30% of maximum power, and (iii) after 5 minutes of exposure to microwave radiation at 90% of maximum power, aging effects are observed (i.e., the fluid film absorbs moisture), and accordingly, peaks corresponding to the vibration frequencies of the hydroxyl groups and increased leakage currents are observed. However, (iv) no changes in FTIR spectra and leakage current were observed in the fluid film after 10 minutes of exposure to microwave radiation at 90% of maximum power, and thus, this fluid film is robust against aging.

[0056] Example 3

[0057] An SiO-based fluid film was formed on a substrate using an oxygen-containing plasma generated from an RPS source by the method (100) described above and an organosilicon compound containing silicon, nitrogen, hydrogen, and chlorine as a dielectric precursor. The formed fluid film was then exposed to microwave radiation at 5.8 GHz in a nitrogen atmosphere at atmospheric pressure at room temperature. In FIG. 7a, FTIR spectra of the fluid film are shown: (i) immediately after delivery, and (iv) after 10 minutes of exposure to microwave radiation at 90% of the maximum power (1.6 kW). As can be seen in FIG. 7a, the 1130–1000 cm⁻¹ corresponds to the vibration frequency of the siloxane functional group (Si-O-Si). -1The peak in the range of (iv) increased after 10 minutes of exposure to microwave radiation at 90% of maximum power, which indicates that the cross-linking of polymers in the fluid membrane is improved (i.e., by removing hydroxyl groups (-OH) and forming siloxane functional groups (Si-O-Si). This improvement in cross-linking can be confirmed by a decrease in the ratio of the wet etch rate (WERR) of the fluid membrane to the thermal oxide membrane using diluted hydrofluoric acid (DHF, 100:1), as shown in Figures 7b and 7c, and a decrease in reflectance. In the fluid film, the wet etching rate changes from 11.74 Å / min (angstrom per minute) to 9.42 (Å / min) after (i) immediately after delivery, (ii) after 10 minutes of exposure to microwave radiation at 30% of maximum power, and (iii) after 5 minutes of exposure to microwave radiation at 90% of maximum power. The reflectance at wavelength (663 nm) is reduced to less than 1.50 by microwave treatment.

[0058] As discussed above, dielectric films can be cured, and hydroxyl groups (-OH) can be removed by exposure to microwave radiation, and the shrinkage rate of dielectric films is reduced compared to thermal annealing or UV irradiation. The removal of hydroxyl groups (-OH) leads to a reduction in the effects of aging, resulting in increases in the density and strength of the dielectric films. It should be noted that the specific exemplary embodiments described above are merely some possible examples of dielectric films that can be post-treated by microwave radiation according to the present disclosure and do not limit the possible configurations, specifications, deposition methods, etc. of the dielectric films. For example, post-treatment by microwave radiation may be applied to any doped or undoped SiCOH, SiCON, SiO, and SiN films or silicon-containing dielectric films deposited by other methods, such as chemical vapor deposition (CVD) or atomic layer deposition (ALD).

[0059] Although the foregoing relates to specific embodiments, other and additional embodiments may be devised without departing from the basic scope of the invention, and the scope of the invention is determined by the following claims.

Claims

Claim 1 A method for post-processing a dielectric film formed on the surface of a substrate, comprising the steps of: positioning the substrate, on which a liquid phase fluid dielectric film is formed, in a processing chamber ― said liquid phase fluid dielectric film comprises hydroxyl groups (-OH) ―; and exposing said liquid phase fluid dielectric film in the processing chamber to microwave radiation of a frequency of 5 GHz to 7 GHz at atmospheric pressure to remove said hydroxyl groups (-OH), wherein said liquid phase fluid dielectric film is non-thermally cured by said microwave radiation. Claim 2 A method for post-processing a dielectric film formed on the surface of a substrate, wherein the liquid-phase fluid dielectric film comprises silicon, in accordance with claim 1. Claim 3 delete Claim 4 A method for post-processing a dielectric film formed on the surface of a substrate, wherein, in claim 1, the microwave radiation is 5.8 GHz and the substrate is at a temperature of room temperature to 450°C during exposure of the liquid-phase fluid dielectric film to microwave radiation. Claim 5 In claim 1, the liquid-phase fluid dielectric membrane is 0.7 W / cm² for a time duration of 1 to 20 minutes. 2 Up to 7.0 W / cm 2 A method for post-processing a dielectric film formed on the surface of a substrate, which is exposed to microwave radiation from an ambient gas selected from nitrogen, helium, argon, hydrogen, oxygen, air, and water vapor at atmospheric pressure at a power density of . Claim 6 A method for post-processing a dielectric film formed on the surface of a substrate, wherein the substrate is made of a material selected from the group consisting of metal, semiconductor, and plastic. Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete

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