Method of deposition

Abstract

Embodiments of the present application relate to a deposition method. According to the present application, a method of depositing a hydrogenated silicon carbon nitride (SiCN:H) film on a substrate by plasma enhanced chemical vapor deposition (PECVD) is provided, comprising: providing the substrate in a chamber; introducing silane (SiH4), a carbon-providing precursor, and nitrogen (N2) into the chamber; and maintaining a plasma in the chamber so as to deposit SiCN:H on the substrate by PECVD, wherein the substrate is maintained at a temperature of less than about 250 °C.

Description

Technical Field

[0001] This invention relates to a method for depositing silicon-carbon nitride films by plasma-enhanced chemical vapor deposition (PECVD). In particular, this invention relates to a method for depositing hydrogenated silicon-carbon nitride (SiCN:H) films by PECVD. The invention also relates to a substrate having the associated SiCN:H film. Furthermore, the invention relates to a method for bonding two substrates, and related apparatus comprising the two bonded substrates. Background Technology

[0002] In the foreseeable future, two-dimensional (2D) scaling of electronic devices based on Moore's Law will continue. However, three-dimensional (3D) integration of devices, whether homogeneous or heterogeneous, offers enormous potential for the development of advanced systems. It is believed that “stacked” devices in 3D can achieve greater integration compared to 2D scaling methods, which in turn will provide improved device performance, enhanced functionality, and ultimately, reduced costs.

[0003] To achieve efficient 3D integration of devices, it is desirable to bond two substrates (such as device wafers) together, enabling the simultaneous stacking of a large number of dies. Surface-activated bonding techniques are promising candidates for achieving suitable 3D stacking of devices. Typically, surface-activated bonding processes involve treating the surfaces of two substrates, for example, with a dielectric bonding / adhesion layer, such as a silicon-carbon nitride (SiCN) layer (containing a hydrogenated silicon-carbon nitride (SiCN:H) layer). The two treated surfaces can then be smoothed and precisely aligned using chemical mechanical planarization (CMP), pressed together at elevated temperatures, and annealed to bond the substrates together.

[0004] Known surface-activated bonding techniques utilize dielectric bonding layers and adhesion layers, such as SiCN and SiCN:H, which are deposited at high temperatures (approximately 340–370 °C) and may require further densification steps at approximately 420 °C prior to bonding. Due to the high temperatures required, these known processes are unsuitable for bonding substrates with low thermal budget constraints (i.e., temperature-sensitive substrates). For example, it is crucial for substrates comprising device layers and / or interconnects (which may contain copper layers embedded in the dielectric) to maintain a low thermal budget to avoid damaging the device.

[0005] However, simply lowering the deposition temperature of the bonding and adhesion layers results in poor adhesion strength, poor copper barrier properties, and high sensitivity to moisture. Therefore, simply lowering the temperature of known deposition processes provides unacceptable results.

[0006] Therefore, a method is needed in which dielectric barrier layers and adhesion layers for wafer-to-wafer bonding can be deposited at significantly lower temperatures while maintaining excellent device performance. This is desirable because it allows for the use of surface-activated bonding techniques to bond a wider variety of substrates, particularly those with low thermal budget constraints. By providing this method, improved 3D integration of devices can be achieved, which is expected to enhance device performance. Summary of the Invention

[0007] The present invention seeks to address at least some of the aforementioned problems, expectations, and needs in at least some of its embodiments. Specifically, embodiments of the present invention seek to provide a method for depositing hydrogenated silicon-carbon nitride (SiCN:H) films that maintains a low thermal budget for the substrate. The SiCN:H films deposited by the method of the present invention are suitable for use as adhesion layers in surface-activated bonding techniques while remaining within low thermal budget constraints. The films also exhibit good copper barrier properties and are stable in the presence of moisture.

[0008] According to a first aspect of the present invention, a method for depositing a hydrogenated silicon-carbon nitride (SiCN:H) film on a substrate by plasma-enhanced chemical vapor deposition (PECVD) is provided, comprising:

[0009] The substrate is provided in the chamber;

[0010] Silane (SiH4), a carbon-donating precursor, and nitrogen (N2) are introduced into the chamber; and

[0011] Plasma is maintained in the chamber to deposit SiCN:H on the substrate by PECVD, wherein the substrate is maintained at a temperature below about 250°C.

[0012] It has been found that using a deposition formulation comprising a combination of silane (SiH4), a separate carbon-donating precursor, and nitrogen (N2) as the reactive precursor to produce stable SiCN:H films with good barrier and bonding layer properties while remaining within low thermal budget constraints. SiCN:H films are suitable as adhesion layers in surface-activated bonding processes. Therefore, this method is suitable for 3D integration of various substrates, including device wafers containing temperature-sensitive device layers and interconnects that can be embedded in the substrate. The reactive precursor used can consist essentially of a combination of silane (SiH4), a separate carbon-donating precursor, and nitrogen (N2). Preferably, the reactive precursor used consists of a combination of silane (SiH4), a separate carbon-donating precursor, and nitrogen (N2). Optionally, one or more non-reactive carrier gases can also be introduced into the chamber.

[0013] The carbon-donating precursor can be an organosilane, a gaseous hydrocarbon, or a combination thereof. Preferably, the carbon-donating precursor is an organosilane. The organosilane can be an alkylsilane. The organosilane can be selected from methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, or a combination thereof. Preferably, the organosilane is trimethylsilane or tetramethylsilane. Most preferably, the organosilane is trimethylsilane. It has been found that deposition formulations comprising a combination of silane (SiH4), organosilane, and nitrogen (N2) can be used to produce SiCN:H films with particularly desirable properties, for example, as a good copper barrier layer. Optionally, the carbon-donating precursor can be a gaseous hydrocarbon. The gaseous hydrocarbon can be methane (CH4) or acetylene (C2H2).

[0014] Silane (SiH4) is a silicon precursor. Silane (SiH4) can be introduced into the chamber at a flow rate in the range of 100-500 sccm, optionally 200-400 sccm, optionally 250-300 sccm, or optionally about 275 sccm.

[0015] The carbon precursor can be introduced into the chamber at a flow rate in the range of 10-90 sccm, optionally 20-70 sccm, or optionally 25-55 sccm.

[0016] The carbon precursor can be introduced into the chamber at a flow rate less than that of silane (SiH4). The flow rate of the carbon precursor can be about 2-50%, optionally about 5-25%, optionally about 7-20%, optionally about 8-15%, or optionally about 10-11% of the flow rate of silane (SiH4).

[0017] Silane (SiH4) and a carbon-donating precursor, such as trimethylsilane, can be introduced into the chamber at a ratio (in sccm) ranging from 3:1 to 30:1, optionally 4:1 to 25:1, optionally 5:1 to 20:1, optionally about 7:1 to 15:1, optionally about 10:1 to 12:1, or optionally about 11:1. Introducing silane (SiH4) and the carbon-donating precursor into the chamber at these ratios can improve the adhesion properties of the deposited SiCN:H film while maintaining high resistance to moisture absorption. Without wishing to be bound by any theory or speculation, it is believed that the improved adhesion properties are a result of increased carbon content in the deposited SiCN:H film. For example only, when the carbon-donating precursor is trimethylsilane, a silane (SiH4) to trimethylsilane ratio of about 10:1 to 12:1, or most preferably 11:1, is preferred.

[0018] Nitrogen (N2) is a nitrogen-donating precursor. Nitrogen (N2) can be introduced into the chamber at a flow rate in the range of 1000-10,000 sccm, optionally 2,500-9,000 sccm, optionally 4,000-8,000 sccm, or optionally 6,000-7,000 sccm. Optionally, ammonia (NH3) is not present as a nitrogen-donating precursor. Advantageously, N2 is the only nitrogen-donating precursor used.

[0019] During the PECVD step, the substrate can be maintained at a temperature below 225°C, optionally below 200°C, or optionally about 175°C or lower. The substrate can also be maintained at temperatures above 100°C, optionally above 125°C, or optionally above 150°C. Maintaining the substrate at these temperatures keeps it within low thermal budget constraints, making this method suitable for depositing SiCN:H films on temperature-sensitive substrates. For example, the method can be used to deposit a SiCN:H (adhesive) layer on a temperature-sensitive substrate including device layers and / or interconnects, which may comprise copper layers embedded in a dielectric.

[0020] When the plasma is sustained in the chamber, the chamber may have a pressure in the range of 1,000-5,000 mTorr, optionally 1,400-3,000 mTorr, optionally about 1,600 mTorr.

[0021] High-frequency RF power can be used to sustain the plasma. Alternatively, both high-frequency and low-frequency RF power can be used to sustain the plasma.

[0022] The high-frequency RF power can have a frequency in the range of 10-15MHz, preferably 13.56MHz. The high-frequency RF power can have a power in the range of 250-1,250W, optionally 500-1,000W, optionally 700-900W, or optionally about 800W.

[0023] The low-frequency RF power can have a frequency range of 100-500 kHz, optionally about 200-450 kHz, optionally about 300-400 kHz, or optionally about 380 kHz. The low-frequency RF power can have a power range of 0-400 W, optionally 50-300 W, or optionally 100-200 W.

[0024] This method may further include a subsequent step of performing hydrogen plasma treatment, which involves exposing the SiCN:H film to hydrogen plasma. Hydrogen plasma treatment can further improve the stability of the SiCN:H film. Without being bound by any theory or speculation, it is believed that hydrogen plasma treatment acts to passivate the surface of the SiCN:H film, thereby preventing surface moisture absorption and SiO formation. Hydrogen plasma treatment can be performed without vacuum interruption. Hydrogen plasma treatment can be performed without exposing the SiCN:H film to water vapor.

[0025] During hydrogen plasma processing, the substrate can be maintained at a temperature below about 200°C, optionally below about 175°C, optionally below about 150°C, or optionally about 125°C.

[0026] Hydrogenated silicon-carbon nitride (SiCN:H) films can be amorphous films (e.g., a-SiCN:H).

[0027] The substrate can be a semiconductor substrate.

[0028] According to a second aspect of the invention, a substrate on which a SiCN:H film is deposited using the method according to the first aspect is provided.

[0029] The substrate may be a semiconductor substrate. The substrate may be a silicon substrate or a silicon wafer. The substrate may include multiple dies. The substrate may include features such as one or more device layers and / or interconnects. Features may be temperature-sensitive. Features may include copper layers, such as copper layers embedded in a dielectric material.

[0030] SiCN:H films can have a refractive index in the range of about 2.0. SiCN:H films can have a refractive index of about 1.85-2.2, optionally 1.95-2.10, optionally 1.97-2.03 or optionally 1.99-2.00.

[0031] SiCN:H films can have a SiC:SiN ratio (based on FTIR peak area) of less than about 0.01, optionally less than about 0.005, optionally about 0.004.

[0032] SiCN:H films can have a SiCH content of less than about 0.01, optionally about 0.008. x SiN ratio (based on FTIR peak area).

[0033] SiCN:H films can have an NH:SiN ratio of less than about 0.02, optionally about 0.018 (based on FTIR peak area).

[0034] Compared to known deposition formulations performed at low temperatures (e.g., less than about 250°C), SiCN:H films deposited using the method of the present invention typically exhibit a lower SiC:SiN ratio and a lower SiCH content. x The SiN:H ratio and the lower NH:SiN ratio (based on FTIR peak area) indicate a high-density SiCN (or SiCN:H) film.

[0035] SiCN:H films can have a SiH:SiN ratio (based on FTIR peak area) greater than about 0.8, optionally greater than about 0.10, and optionally about 0.12. SiCN:H films deposited using the method according to the invention typically exhibit a characteristically high SiH:SiN ratio (based on FTIR peak area). SiCN:H films can have a hydrogen content greater than about 2 at%, optionally greater than about 5 at%, or optionally greater than about 10 at%.

[0036] According to a third aspect of the present invention, a method for bonding two substrates is provided, comprising the following steps:

[0037] A first substrate having a SiCN:H film according to the second aspect is provided;

[0038] A second substrate having a SiCN:H film according to the second aspect is provided; and

[0039] The SiCN:H film of the first substrate is brought into contact with the SiCN:H film of the second substrate at a temperature below about 250°C, so as to bond the SiCN:H film of the first substrate to the SiCN:H film of the second substrate.

[0040] The SiCN:H film of the first substrate can be brought into contact with the SiCN:H film of the second substrate at a temperature within the range of 100-250°C, optionally 125-225°C, optionally 150-200°C, or optionally about 175°C.

[0041] The method of combining two substrates may further include a smoothing step, such as a chemical mechanical planarization (CMP) step, to smooth the SiCN:H film on the first substrate and / or the second substrate. The method of combining two substrates may further include a step of aligning the first substrate and the second substrate before bringing the SiCN:H films of the first substrate and the second substrate into contact.

[0042] According to a fourth aspect of the invention, an apparatus is provided comprising a stack of two or more substrates produced using the method of the third aspect.

[0043] Although the invention has been described above, it extends to any inventive combination of features described above or below, in the drawings, or in the claims. For example, any feature disclosed with respect to one aspect of the invention may be combined with any feature disclosed with respect to any other aspect of the invention. Attached Figure Description

[0044] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0045] Figure 1 This is a schematic side view of two substrates for a substrate-substrate bonding process to be prepared for surface activation;

[0046] Figure 2 The FTIR spectra of the SiCN:H films deposited using comparative examples are shown.

[0047] Figure 3 The FTIR spectra of the SiCN:H films deposited using comparative examples are shown.

[0048] Figure 4 The FTIR spectra of SiCN:H films deposited using the method of the present invention and comparative examples are shown.

[0049] Figure 5 This is a graph showing the carbon content in the deposited SiCN:H layer as a function of the ratio of carbon precursor to silane.

[0050] Figure 6 It is a graph showing the change in refractive index (RI) as a function of the ratio of carbon precursor to silane over a six-day period;

[0051] Figure 7 The FTIR spectra of the SiCN:H film before and after exposure to air for six days are shown.

[0052] Figure 8 This is a graph showing the refractive index (RI) variation of a SiCN:H film deposited using the exemplary method of the present invention;

[0053] Figure 9 The FTIR spectrum of SiCN:H deposited using the exemplary method of the present invention is shown; and

[0054] Figure 10 This is a graph showing the refractive index variation of a SiCN:H film deposited using an exemplary method of the present invention. Detailed Implementation

[0055] Figure 1A schematic diagram of a surface-activated bonding process for joining two substrates together is shown. Substrates 10a and 10b may include temperature-sensitive features, such as device layers 12a and 12b. Adhesion layers 14a and 14b, such as silicon-carbon nitride (SiCN) layers or hydrogenated silicon-carbon nitride (SiCN:H) layers, are deposited on the surface of each substrate 10a and 10b. The two adhesion layers 14a and 14b may be smoothed, precisely aligned, pressed together at elevated temperatures, and annealed, for example, by chemical mechanical planarization (CMP), to bond the two substrates together via adhesion layers 14a and 14b.

[0056] According to the exemplary method (and comparative example) of the present invention, the apparatus suitable for depositing silicon carbon nitride (SiCN) films (such as SiCN:H films) includes SPTS Delta. TM A parallel plate PECVD apparatus, available from SPTS Technologies Limited, located in Newport, South Wales, UK. All exemplary and comparative examples described below were performed using this apparatus.

[0057] Comparison of Examples 1 and 2

[0058] It is known to use organosilanes and ammonia (NH3) as reactive precursors to deposit SiCN:H adherent layers using high-temperature (e.g., about 340-370 °C) plasma-enhanced chemical vapor deposition (PECVD). The organosilanes act as silicon and carbon donor precursors, while ammonia acts as a nitrogen donor precursor.

[0059] As a comparative example (and reference) Figure 2 Using organosilanes and ammonia (NH3) as reactive precursors, SiCN:H films were deposited onto a 300 mm silicon wafer via PECVD at 350 °C. The chamber pressure was maintained in the range of 1-5 Torr. In Comparative Example 1 (… Figure 2 In line 21), trimethylsilane (3MS) was used as an organosilane precursor. In Comparative Example 2 ( Figure 2 In line 22), tetramethylsilane (4MS) is used as an organosilane precursor.

[0060] In Comparative Examples 1 and 2, at approximately 1257 cm -1 Characteristic Si-CH3 stretching peaks are visible, but they are more pronounced when 3MS is used as the organosilane precursor (i.e., Comparative Example 1, line 21). Spectra 21 and 22 correspond to Si-H... n (n = 1 - 3) and CH m (m=1-3) The stretching peak is approximately 2133 cm⁻¹ -1 Approximately 2900cm-1 Similar intensity peaks were observed at all locations.

[0061] Compare Examples 3 and 4

[0062] As a further comparative example (and see also...) Figure 3 Using trimethylsilane (3MS) and ammonia (NH3) as reactive precursors, SiCN:H films were deposited onto a 300 mm silicon wafer via PECVD. A mixed-frequency RF power was used to maintain the plasma. That is, high-frequency (HF) RF (operating at 13.56 Hz) and low-frequency (LF) RF (operating at 380 kHz) were used to maintain the plasma. Comparative Example 3 ( Figure 3 Line 33) and Comparative Example 4 ( Figure 3 Line 34) uses the same deposition parameters, except that Comparative Example 3 uses a high deposition temperature of 370°C, while Comparative Example 4 uses a low deposition temperature of 175°C.

[0063] The SiCN:H film deposited in Comparative Example 3 (line 33) exhibits acceptable performance as an adhesion layer and / or copper barrier layer. However, the high temperatures required to deposit this film cannot be used on temperature-sensitive substrates (i.e., substrates with low thermal budget constraints).

[0064] Compared to the film deposited at 370°C (Comparative Example 3, line 30), the SiCN:H film deposited in Comparative Example 4 (i.e., at a lower temperature of 175°C, line 34) shows a Si-CH3 stretching peak (approximately 1257 cm⁻¹). -1 ), Si-H n (n=1-3) Stretching peak (approximately 2133cm) -1 ) and CH m (m=1-3) Tensile peak (approximately 2900 cm⁻¹) -1 A significant increase in ( ). Furthermore, in the 600-1200cm range... -1 The peaks at these locations are more prominent for SiCN:H films deposited at 175 °C. These FTIR spectra indicate that the SiCN:H films deposited at 175 °C contain more CH4 compared to those deposited at 370 °C. n Si-CH n Si-H n (n = 1 - 3) end bases.

[0065] The SiCN:H film deposited in Comparative Example 4 (i.e., at 175°C using 3MS and NH3 as reaction precursors) has a low density and a low refractive index of approximately 1.57. Due to the low density and porosity of the film, the SiCN:H film deposited in Comparative Example 4 absorbs moisture. The film of Comparative Example 4 is not feasible as an adhesion layer. Furthermore, due to the low density, the film will be a poor copper barrier layer and may degas during the bonding process, which will adversely affect the substrate-substrate bonding strength. The unacceptable film formed in Comparative Example 4 demonstrates that depositing an acceptable SiCN:H film at low temperatures (e.g., <250°C) is not a trivial change.

[0066] Exemplary embodiments

[0067] This invention provides a method for depositing a hydrogenated silicon-carbon nitride (SiCN:H) film, which can be used as an adhesion layer in a surface-activated bonding process. Specifically, an acceptable SiCN:H film can be deposited on a substrate at a temperature below about 250°C, optionally below 200°C, optionally about 175°C. The substrate can be a semiconductor substrate, such as a silicon substrate or a silicon wafer. The substrate can include multiple dies. The substrate can include temperature-sensitive features, such as device layers and interconnects, and may contain a copper layer embedded in a dielectric.

[0068] Exemplary embodiments of the present invention include introducing a silicon-donating precursor, a carbon-donating precursor, and a nitrogen-donating precursor into a PECVD chamber. Optionally, one or more non-reactive carrier gases may also be introduced into the chamber. A plasma is maintained within the chamber to allow for the PECVD process, which deposits SiCN:H onto a substrate. The silicon-donating precursor is silane (SiH4). The nitrogen-donating precursor is nitrogen (N2). The carbon-donating precursor may be an organosilane, methane (CH4), acetylene (C2H2), or a combination thereof. The organosilane may be methylsilane, dimethylsilane, trimethylsilane (3MS), tetramethylsilane (4MS), or a combination thereof.

[0069] Table 1 shows exemplary PECVD process parameters suitable for obtaining stable SiCN:H films at deposition temperatures in the range of 100-250°C.

[0070] Table 1

[0071]

[0072] Example 5

[0073] In one exemplary embodiment (Example 5), a SiCN:H film is deposited onto a 300 mm silicon wafer by PECVD at 175 °C. The reactive precursors are silane (SiH4), trimethylsilane (3MS) as a carbon donor precursor, and nitrogen (N2).

[0074] The use of a combination of (carbon-free) silanes and discrete carbon-containing precursors allows for fine-tuning and controlled variation of the carbon content in SiCN:H films. This is also more cost-effective than using a single organosilane precursor. Chamber pressure is in the range of 1–5 Torr. A mixed-frequency RF power is used to sustain the plasma. The mixed-frequency RF power includes a high-frequency RF (operating at 13.56 Hz) and a low-frequency RF (operating at 380 kHz).

[0075] Figure 4 The FTIR spectrum (line 45) of the SiCN:H film deposited using the method in Example 5 is shown. Line 43 ( Figure 4 This corresponds to the SiCN:H film deposited at 370°C under the same conditions as those used in Comparative Example 3. Comparative Example 3 is used here as an exemplary spectrum of a SiCN:H film suitable for use as an adhesion layer.

[0076] Table 2 shows the FTIR peak areas after normalizing the results using the SiN peak.

[0077] Table 2

[0078]

[0079] The FTIR spectrum (line 45) of the SiCN:H film deposited using the low-temperature (LT) method in Example 5 is similar to the FTIR spectrum (lines 33, 43) of the film deposited in Comparative Example 3. However, the SiCN:H film of Example 5 exhibits a stronger Si-H peak (approximately 2120 cm⁻¹) than that of the film deposited using the high-temperature (HT) method in Comparative Example 3. -1 These are characteristic properties of SiCN:H films deposited using the method of the present invention.

[0080] Furthermore, based on Table 2, it is evident that the SiC / SiN and SiCH in Example 5... x The / SiN and NH / SiN ratios are a better match for Comparative Example 3 than those for Comparative Example 4. Furthermore, the refractive indices of Comparative Example 3 and Example 5 are closely matched. The low refractive index of Comparative Example 4 indicates that the film has a very low density and is unsuitable for use as an adhesion layer. Example 5 yielded a significantly superior film compared to Comparative Example 4 (also deposited at low temperature, but using a known deposition formulation). The use of a mixture of reactive precursors comprising silane (SiH4), a carbon-donating precursor, and nitrogen (N2) provided suitable conditions for depositing the SiCN:H film, which exhibited improved quality while maintaining a low thermal budget. The SiCN:H film deposited using this method can be used as an adhesion layer in surface-activated bonding processes and can provide acceptable copper barrier properties.

[0081] Although Example 5 uses the 3MS carbon-donating precursor, acceptable results are expected if the 3MS precursor is replaced by other carbon-donating precursors (such as alternative organosilanes, such as tetramethylsilane (4MS)).

[0082] The ratio of carbon-donating precursor to silane can be altered by changing the flow rate of the reactive precursor. Figure 5 This illustrates how the ratio (in percentage) of the carbon precursor (i.e., 3MS in this example) to silane (SiH4) affects the SiC / SiN ratio (approximately 1250 cm⁻¹). -1 ) and SiCH x / SiN (approximately 2900cm) -1 FTIR peak area ratio (50 and 52 respectively). Peak area compared to the main SiN peak area (approximately 840 cm⁻¹). -1 The ratio is proportional to the change in film thickness to normalize the result. Controlling the ratio of carbon precursor to silane (SiH4) allows the carbon content of the film to vary in a controllable manner.

[0083] Figure 6 This illustrates how the ratio (in percentage) of the carbon-donating precursor (i.e., 3MS in this example) to silane (SiH4) affects the stability of the refractive index measured over a six-day period. A lower 3MS / SiH4 flow ratio yields less change (reduction) in RI over time, indicating a more stable membrane that is less sensitive to moisture. A 3MS / SiH4 ratio of approximately 20% provides an acceptable change in RI of less than 0.14. However, a 3MS / SiH4 flow ratio of approximately 10% provides a significant improvement in the stability of the measured RI. Changing the flow ratio of the carbon-donating precursor to silane allows for fine-tuning of the carbon content in the SiCN:H membrane. Without wishing to be bound by any theory or speculation, it is believed that a higher carbon content in the membrane can provide improved binding strength. However, SiCN:H membranes with higher carbon content are also more hygroscopic and therefore less stable.

[0084] Figure 7 The results show that the FTIR spectra of the SiCN:H films deposited using these methods did not exhibit significant changes over a six-day period, indicating that the films are stable. In particular, no Si-O peak (approximately 1050 cm⁻¹) was observed after six days of atmospheric exposure. -1 The increase in ) was observed, and only the -OH peak (approximately 3350 cm⁻¹) was observed. -1 The minimum increase in ) indicates that the membrane is stable and that only minimal water vapor absorption occurs after exposure to the atmosphere at room temperature.

[0085] Figure 8 This shows how the refractive index changes over a six-day period when exposed to the atmosphere. An initial decrease in RI was observed in the first 24 hours. However, thereafter, the RI remained stable at approximately 2.00.

[0086] Post-deposition treatment

[0087] Optional post-deposition treatments can be performed on the SiCN:H films deposited using the method of the present invention. Post-deposition treatments can improve the stability of the film and further increase (decrease) the film's sensitivity to moisture. Post-deposition treatments can be thermal annealing, plasma treatment (such as hydrogen plasma treatment), electron beam treatment, ultraviolet curing technology, or a combination thereof. Preferably, the post-deposition treatment is hydrogen plasma treatment.

[0088] Hydrogen plasma treatment may include exposing the deposited SiCN:H film to hydrogen plasma, preferably in a vacuum without interruption and / or without exposure to water vapor / moisture. Hydrogen plasma treatment may include introducing a hydrogen precursor into a chamber and sustaining the plasma. The pressure in the chamber may be approximately 2 Torr. A high-frequency RF power of approximately 1 kW (e.g., operating at 13.56 MHz) may be used to sustain the plasma. The hydrogen plasma treatment may be performed for a duration of approximately 30-300 seconds, optionally approximately 60 seconds. During hydrogen plasma treatment, the substrate may be maintained at a temperature lower than the temperature used for the SiCN:H deposition step. For example, during hydrogen plasma treatment, the substrate may be maintained at a temperature of approximately 200°C or lower, optionally approximately 175°C or lower, optionally approximately 150°C or lower, or optionally approximately 125°C. Performing hydrogen plasma treatment at a low temperature (e.g., below the SiCN:H deposition step) keeps the substrate within low thermal budget constraints. This helps to avoid damaging any temperature-sensitive properties of the substrate.

[0089] Figure 9 The results show how the FTIR spectra changed over six days with and without post-deposition hydrogen plasma treatment (lines 90 and 92, respectively).

[0090] Figure 10 The effects of post-deposition hydrogen plasma treatment on the RI stability of the deposited SiCN:H film over a six-day period are illustrated. Without post-deposition hydrogen plasma treatment (line 100), an initial decrease in RI was observed in the first 24 hours. However, thereafter, RI remained stable at approximately 2.00. However, the use of post-deposition hydrogen plasma treatment further improved the stability of RI (line 102). Negligible changes in RI were observed over the six-day period, with RI maintaining values ​​of approximately 2.02–2.03. Without being bound by any theory or speculation, it is believed that hydrogen plasma treatment passivates the SiCN:H surface, thereby preventing moisture absorption. Post-deposition hydrogen plasma treatment can be used to improve the stability of SiCN:H films.

Claims

1. A method for depositing a hydrogenated silicon-carbon nitride (SiCN:H) film on a substrate by plasma-enhanced chemical vapor deposition (PECVD), comprising: The substrate is provided in the chamber of a parallel-plate PECVD apparatus; Silane (SiH4), a carbon-donating precursor, and nitrogen (N2) are introduced into the chamber, wherein the silane (SiH4) and the carbon-donating precursor are introduced into the chamber at a flow rate in the range of 5:1 to 20:1 in sccm, wherein the flow rate of the silane (SiH4) and the flow rate of the carbon-donating precursor are independently controlled during the introduction, and wherein the carbon-donating precursor is an organosilane; as well as Plasma is maintained in the chamber to deposit SiCN:H on the substrate by PECVD, wherein the substrate is maintained at a temperature below 225°C, and the chamber has a pressure in the range of 1-5 Torr while the plasma is maintained in the chamber.

2. The method according to claim 1, wherein the organosilane is selected from methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, or combinations thereof.

3. The method according to any of the preceding claims, wherein silane (SiH4) is introduced into the chamber at a flow rate in the range of 100-500 sccm.

4. The method according to claim 1 or 2, wherein the carbon precursor is introduced into the chamber at a flow rate in the range of 10-90 sccm.

5. The method according to claim 1 or 2, wherein nitrogen (N2) is introduced into the chamber at a flow rate in the range of 1000-10,000 sccm.

6. The method according to claim 1 or 2, wherein when the plasma is maintained in the chamber, the chamber has a pressure in the range of 1.4-3 Torr.

7. The method according to claim 1 or 2, further comprising the subsequent step of performing hydrogen plasma treatment, said hydrogen plasma treatment comprising exposing the SiCN:H film to hydrogen plasma.

8. The method of claim 7, wherein during the hydrogen plasma treatment, the substrate is maintained at a temperature below 200°C.

9. The method according to claim 1 or 2, wherein the hydrogenated silicon carbon nitride film is an amorphous hydrogenated silicon carbon nitride film (a-SiCN:H).

10. The method according to claim 1 or 2, wherein the substrate is a semiconductor substrate.

11. The method of claim 3, wherein silane (SiH4) is introduced into the chamber at a flow rate in the range of 200-400 sccm.

12. The method of claim 3, wherein silane (SiH4) is introduced into the chamber at a flow rate in the range of 250-300 sccm.

13. The method of claim 3, wherein silane (SiH4) is introduced into the chamber at a flow rate of 275 sccm.

14. The method of claim 4, wherein the carbon precursor is introduced into the chamber at a flow rate in the range of 20-70 sccm.

15. The method of claim 4, wherein the carbon precursor is introduced into the chamber at a flow rate in the range of 25-55 sccm.

16. The method of claim 1, wherein silane (SiH4) and the carbon-donating precursor are introduced into the chamber at a flow rate in the range of 7:1 to 15:1 in sccm.

17. The method of claim 1, wherein the silane (SiH4) and the carbon-supplying precursor are introduced into the chamber at a flow rate in the range of 10:1 to 12:1 in sccm.

18. The method of claim 1, wherein silane (SiH4) and the carbon-donating precursor are introduced into the chamber at a flow rate of 11:1 per sccm.

19. The method of claim 5, wherein nitrogen (N2) is introduced into the chamber at a flow rate in the range of 2,500-9,000 sccm.

20. The method of claim 5, wherein nitrogen (N2) is introduced into the chamber at a flow rate in the range of 4,000-8,000 sccm.

21. The method of claim 5, wherein nitrogen (N2) is introduced into the chamber at a flow rate in the range of 6,000-7,000 sccm.

22. The method of claim 1, wherein the substrate is maintained at a temperature below 200°C.

23. The method of claim 1, wherein the substrate is maintained at a temperature of 175°C or lower.

24. The method of claim 6, wherein the chamber has a pressure of 1.6 Torr when the plasma is maintained in the chamber.

25. The method of claim 8, wherein during the hydrogen plasma treatment, the substrate is maintained at a temperature below 175°C.

26. The method of claim 8, wherein during the hydrogen plasma treatment, the substrate is maintained at a temperature below 150°C.

27. The method of claim 8, wherein during the hydrogen plasma treatment, the substrate is maintained at a temperature below 125°C.

28. A substrate having a SiCN:H film deposited using the method according to any of the preceding claims.

29. The substrate according to claim 28, wherein the SiCN:H film has a hydrogen content greater than 2 at%.

30. The substrate according to claim 29, wherein the SiCN:H film has a hydrogen content greater than 5 at%.

31. The substrate according to claim 29, wherein the SiCN:H film has a hydrogen content of greater than 10 at%.

32. A method for bonding two substrates, comprising the following steps: A first substrate is provided, the first substrate being the substrate according to claim 28, having a SiCN:H film; A second substrate is provided, the second substrate being the substrate according to claim 28, having a SiCN:H film; and The SiCN:H film of the first substrate is bonded to the SiCN:H film of the second substrate at a temperature below 250°C.

33. A stack comprising two substrates combined using the method of claim 32.

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