Processing silicon nitride-based dielectric films

Abstract

This disclosure provides a method for gap-filling deposition. This method includes forming a silicon nitride-based dielectric film by providing a substrate to a processing chamber. An amorphous silicon dioxide layer is formed on the surface of the substrate by flowing a dielectric precursor on the substrate. A modified amorphous silicon dioxide layer is formed by flowing a reactive gas into the processing chamber. The modified amorphous silicon dioxide layer is subjected to a thermal etching process by flowing a fluorine-containing compound at a temperature of about 400°C to about 600°C. The modified amorphous silicon dioxide layer is formed by reacting it with one or more free radicals generated by a remote plasma source. An etched silicon nitride-based dielectric film is formed by flowing a fluorine-containing compound into the processing chamber containing plasma. This etched silicon nitride-based dielectric film is then exposed to a hydrogen recovery process.

Description

Background Technology

[0001] field

[0002] The embodiments of this disclosure generally relate to the fabrication of microelectronic components, and more specifically, to gap-filling deposition and film densification during the fabrication of microelectronic components.

[0003] Related technical descriptions

[0004] Since the introduction of semiconductor device geometries decades ago, the size of these geometries has drastically decreased. Modern semiconductor manufacturing equipment typically produces devices with feature sizes of 10 nm and below, and new equipment is being developed and implemented to manufacture devices with even smaller geometries. This reduction in feature size results in smaller spatial dimensions for structural features on the device. The width of gaps and trenches on the device has narrowed to the point that the aspect ratio of the gap depth to its width has become high enough to make filling the gaps with dielectric material challenging. As a result, dielectric material deposition is prone to blockage at the top before the gap is fully filled, creating voids or seams in the middle of the gap.

[0005] Over the years, numerous techniques have been developed to avoid dielectric material clogging the top of gaps, or to "heal" existing voids or seams. One approach is to etch the dielectric material to remove material blockage at the top of the gap. Unfortunately, during the etching process, the bottom of the gap is etched faster than the top, reducing the thickness of the dielectric material at the bottom and preventing uniform deposition. Conventionally, selective etching is implemented to limit the bottom of the gap to being etched at the same rate as the top. However, methods for controlling the etch selectivity of the dielectric material typically require adjusting one or more process conditions during dielectric material deposition, which can lead to the formation of bubbles within the dielectric material.

[0006] Therefore, an improved method for gap-filling deposition is needed. Summary of the Invention

[0007] This disclosure provides a method for gap-filling deposition. This method includes forming a silicon nitride-based dielectric film. The method includes providing a substrate into a processing chamber. An amorphous silicon dioxide layer is formed on the surface of the substrate by flowing a dielectric precursor and a carrier gas over the substrate. A modified amorphous silicon dioxide layer is formed by flowing a reactive gas into the processing chamber. The modified amorphous silicon dioxide layer is subjected to a thermal etching process by flowing a fluorine-containing compound at a temperature of about 400°C to about 600°C. The modified amorphous silicon dioxide layer is formed by reacting it with one or more free radicals generated by a remote plasma source.

[0008] This disclosure also provides a method for gap-filling deposition. These methods include forming a silicon nitride-based dielectric film. The method includes providing a substrate into a processing chamber. An amorphous silicon dioxide layer is formed on the surface of the substrate by flowing a dielectric precursor and a carrier gas over the substrate. A modified amorphous silicon dioxide layer is formed by flowing a reactive gas into the processing chamber. A silicon nitride-based dielectric film is formed by reacting the modified amorphous silicon dioxide layer with one or more free radicals generated by a remote plasma source. An etched silicon nitride-based dielectric film is formed by flowing a fluorine-containing compound into the processing chamber in the presence of plasma.

[0009] This disclosure also provides a method for gap-filling deposition. These methods include forming a silicon nitride-based dielectric film. The method includes providing a substrate into a processing chamber. An amorphous silicon dioxide layer is formed on the surface of the substrate by flowing a dielectric precursor and a carrier gas over the substrate. A modified amorphous silicon dioxide layer is formed by flowing a reactive gas into the processing chamber. A silicon nitride-based dielectric film is formed by reacting the modified amorphous silicon dioxide layer with one or more free radicals generated by a remote plasma source. An etched silicon nitride-based dielectric film is formed by flowing a fluorine-containing compound into the processing chamber in the presence of plasma. This etched silicon nitride-based dielectric film is exposed to a hydrogen recovery process in the processing chamber. Attached Figure Description

[0010] To gain a more detailed understanding of the features described above, the present disclosure, which has been briefly summarized above, can be described in more detail with reference to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be considered as limiting its scope, and other equally effective embodiments are permissible.

[0011] Figure 1 This is a flowchart illustrating a gap-filling deposition method according to an embodiment of the present disclosure.

[0012] Figure 2 This is a schematic diagram of a clustering tool according to an embodiment of this disclosure.

[0013] Figure 3A This is a schematic diagram of a processing chamber according to an embodiment of the present disclosure.

[0014] Figure 3B This is a schematic bottom view of a nozzle according to an embodiment of the present disclosure.

[0015] Figure 4 This is a schematic diagram of a plasma chamber according to an embodiment of the present disclosure.

[0016] Figure 5This is a table showing a comparison between a reference SiN-based dielectric film having a base film thicker than the sidewall and trench top film thickness according to an embodiment of the present disclosure and a SiN-based dielectric film produced using a thermal NF3 etching process.

[0017] Figure 6 This is a table showing a comparison between a reference SiN-based dielectric film according to an embodiment of the present disclosure and a SiN-based dielectric film produced using a plasma NF3 etching process.

[0018] Figure 7 This is a graph showing the wet etching rates of a reference SiN-based dielectric film according to an embodiment of the present disclosure, a SiN-based dielectric film produced using a plasma NF3 etching process, and a SiN-based dielectric film produced using a plasma NF3 etching process and a recycling process.

[0019] For ease of understanding, the same reference numerals are used where possible to designate common elements in the figures. It is considered that elements and features of one embodiment may be advantageously incorporated into other embodiments without further description. Detailed Implementation

[0020] The embodiments described herein provide a method for depositing a silicon nitride (SiN)-based dielectric film on a substrate. The SiN-based dielectric film can be treated using plasma processing. Additionally, a hydrogen recovery process can be performed to remove one or more defects from the treated SiN-based dielectric film. The SiN-based dielectric film contains silicon-nitrogen (Si-N-Si) bonds. The SiN-based dielectric film deposited on the substrate may contain a large number of silicon-hydrogen (Si-H) and nitrogen-hydrogen (NH) bonds due to Si-H crosslinking near the surface of the deposited SiN-based dielectric film, resulting in insufficient filling of gaps and trenches. The method described herein includes depositing a SiN-based dielectric film on the substrate (e.g., one layer at a time) to prevent precursor buildup in the gaps of the substrate. Furthermore, the SiN-based dielectric film can be etched with NF3, where NF3 becomes a strong oxidant when using high temperatures (e.g., greater than 450°C) and argon-based plasma, allowing selective etching of the top of the gaps while limiting etching of the bottom of the gaps. The SiN-based dielectric film can then be exposed to a hydrogen recovery process to remove defects in the SiN-based dielectric film caused by NF3.

[0021] Figure 1 This is a flowchart of a method 100 for processing a substrate with features during the manufacture of a microelectronic device, according to one or more embodiments described and discussed herein. Method 100 includes gap-filling deposition, etching, and recovery processes.

[0022] At operation 102, a substrate is provided into the processing chamber. For example, the substrate may be a metal substrate (such as aluminum or stainless steel), a semiconductor substrate (such as silicon, silicon-on-insulator (SOI), or gallium arsenide), a glass substrate, or a plastic substrate. The semiconductor substrate may be a patterned substrate at any manufacturing / fabrication stage in the formation of the integrated circuit. The patterned substrate may include one or more features, such as gaps, trenches, holes, vias, fins, pillars, film stacks, layers, films, or other structures disposed on the substrate, which will be filled with a dielectric material. For example, the feature may be or include multiple fins, each fin containing a film stack. The film stack may include alternating pairs of layers disposed on each other. In one or more instances, each of the layer pairs contains a silicon-germanium layer and a silicon dioxide layer. Each of the silicon-germanium layer and the silicon dioxide layer may be deposited or formed independently by an epitaxial growth process or an atomic layer deposition (ALD) process.

[0023] In one or more embodiments, the features may be or include multiple silicon-germanium / silicon (SiGe / Si) fin structures or multiple germanium / silicon (Ge / Si) fin structures. In some examples, each of the SiGe layer, Si layer, or Ge layer has a thickness of about 5 nm to about 30 nm, such as about 5 nm, about 8 nm, or about 10 nm to about 12 nm, about 15 nm, about 20 nm, about 25 nm, or about 30 nm.

[0024] At operation 104, one or more dielectric precursors may flow into the processing chamber via a delivery device, such as a dual-channel showerhead (DCSH). The dielectric precursors may be delivered to the surface of the substrate at a flow rate of approximately 5 sccm to approximately 5000 sccm per DSCH channel, for example, approximately 5 sccm to approximately 250 sccm, approximately 250 sccm to approximately 1000 sccm, approximately 1000 sccm to approximately 2000 sccm, approximately 2000 sccm to approximately 3000 sccm, approximately 3000 sccm to approximately 4000 sccm, or approximately 4000 sccm to approximately 5000 sccm. The surface of the substrate can be from about 40°C to about 150°C, for example, from about 40°C to about 60°C, from about 60°C to about 80°C, from about 80°C to about 100°C, from about 100°C to about 120°C, from about 120°C to about 140°C, or from about 140°C to about 150°C. The pressure in the processing chamber can be from about 0.5 Torr to about 3 Torr, for example, from about 0.5 Torr to about 1 Torr, from about 1 Torr to about 2 Torr, or from about 2 Torr to about 3 Torr.

[0025] In some embodiments, the dielectric precursor is an organosilicon compound. For example, the organosilicon compound may include compounds having silicon, hydrogen, and / or combinations thereof. In one embodiment, the organosilicon compound may include silanes. In some embodiments, a carrier gas (e.g., argon, hydrogen, helium, or combinations thereof) may be used to deliver the dielectric precursor to the surface of the substrate. In one embodiment, the carrier gas may be delivered at a flow rate of about 250 sccm to about 5000 sccm per DSCH channel, for example, about 250 sccm to about 1000 sccm, about 1000 sccm to about 2000 sccm, about 2000 sccm to about 3000 sccm, about 3000 sccm to about 4000 sccm, or about 4000 sccm to about 5000 sccm.

[0026] In one embodiment, the flow ratio of dielectric precursor to carrier gas is from about 1:100 to about 1:500, for example, from about 1:100 to about 1:125, from about 1:125 to about 1:166, or from about 1:166 to about 1:500. Without being bound by theory, a higher carrier gas to dielectric precursor ratio can increase the selective deposition of the dielectric precursor at the bottom of the gap. In one embodiment, the dielectric precursor can be delivered to produce an amorphous silicon dioxide layer formed on and / or on the feature.

[0027] The amorphous silicon dioxide layer may have a thickness of about 20 nm to about 1,000 nm, for example, about 50 nm to about 1,000 nm, about 50 nm to about 800 nm, about 50 nm to about 600 nm, about 50 nm to about 500 nm, about 50 nm to about 400 nm, about 50 nm to about 300 nm, about 50 nm to about 200 nm, about 50 nm to about 100 nm, about 80 nm to about 1,000 nm, about 80 nm to about 800 nm, about 80 nm to about 600 nm, about 80 nm to about 500 nm, about 80 nm to about 400 nm, about 80 nm to about 300 nm, about 80 nm to about 200 nm, about 80 nm to about 100 nm, about 100 nm to about 1,000 nm, about 100 nm to about 800 nm, about 100 nm to about 600 nm, about 100 nm to about 500 nm, about 100 nm to about 400 nm. A thickness of approximately 100 nm to approximately 300 nm, approximately 100 nm to approximately 250 nm, or approximately 100 nm to approximately 200 nm.

[0028] At operation 106, one or more reactive gases (e.g., hydrogen) may flow into the processing chamber via a delivery device to form a modified amorphous silicon dioxide layer. The one or more reactive gases may interact with the amorphous silicon dioxide layer to form an etchant gas, such as SiH4. The etchant gas may react with the amorphous silicon dioxide to form Si-H, Si-Si, and Si-H2 on the surface of the amorphous silicon dioxide layer to form the modified amorphous silicon dioxide layer.

[0029] In some embodiments, at operation 107, a thermal etching process may be performed on the modified amorphous silicon dioxide layer. The thermal etching process may include flowing a fluorinated compound (such as HF, NF3, or a combination thereof) through the modified amorphous silicon dioxide layer at a temperature of about 400°C to about 600°C, for example, about 400°C to about 450°C, about 450°C to about 500°C, about 500°C to about 550°C, or about 550°C to about 600°C. For example, the thermal etching process may include flowing NF3 through the modified amorphous silicon dioxide layer at a temperature of about 450°C. In one embodiment, the temperature of about 400°C to about 600°C allows NF3 to act as a strong oxidizing agent, reacting with Si-Si and Si-H2 bonds at the surface of the modified amorphous silicon dioxide layer to form a uniform Si-H bond layer. Unbound by theory, a uniform Si-H bond layer can allow monolayer Si-H to be nitrated into Si-NH, Si-N2, or Si-N, as described below, to promote uniform deposition of the dielectric film on the substrate.

[0030] The fluorinated compound can be delivered to the substrate at a flow rate of about 500 sccm to about 3000 sccm, for example, about 500 sccm to about 1000 sccm, about 1000 sccm to about 2000 sccm, or about 2000 sccm to about 3000 sccm. The fluorinated compound can be delivered for a time period of about 5 seconds to about 60 seconds, for example, about 5 seconds to about 10 seconds, about 10 seconds to about 20 seconds, about 20 seconds to about 40 seconds, or about 40 seconds to about 60 seconds. Alternatively, the fluorinated compound can be delivered for a time period of more than 60 seconds. During the thermal etching process, the pressure in the processing chamber can be about 4 Torr to about 6 Torr, for example, about 4 Torr to about 4.5 Torr, about 4.5 Torr to about 5 Torr, or about 5 Torr to about 6 Torr.

[0031] Unbound by theoretical constraints, thermal etching can prevent and / or reduce the formation of defects on the surface of modified amorphous silicon dioxide layers, thereby increasing the uniformity of substrate features. Furthermore, thermal etching can form a uniform Si-H bond layer, reducing and / or eliminating the need for argon plasma etching steps while maintaining the quality of the SiN dielectric film.

[0032] At operation 108, one or more free radicals (also referred to as reactive gases) in the substrate processing region react with a modified amorphous silicon dioxide layer to form a silicon nitride (SiN)-based dielectric film. The free radicals can be generated by plasma produced in a remote plasma source (RPS) outside the processing chamber. The free radicals can flow into the substrate processing region of the processing chamber along with a carrier gas (e.g., Ar, He). The plasma can be generated by the dissociation of a processing precursor gas including 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 (e.g., CO, CO2), fluorine-containing compounds (e.g., NF3), or combinations thereof. In the plasma, O-containing compounds can be activated. H F and / or N Free radicals, such as O H F N NH3 N2H4 NH2 NH N O C3H6 C2H2 , or a combination thereof.

[0033] In one embodiment, the ionic energy of the free radical can be from about 25 eV to about 70 eV, for example, from about 25 eV to about 40 eV, from about 40 eV to about 60 eV, or from about 60 eV to about 70 eV. Without being bound by theory, the ionic energy of the free radical at about 25 eV to about 70 eV can reduce defect formation, such as bubbles, in SiN-based dielectric films. In one embodiment, the dose value of the free radical during plasma treatment can be about 1 × 10⁻⁶. 20 ions / cm 2 From approximately 6 × 10 20 ions / cm 2 For example, about 1 × 10 20 ions / cm 2 To approximately 2 × 10 20 ions / cm 2 Approximately 2 × 10 20 ions / cm 2 To approximately 3 × 10 20 ions / cm 2Approximately 3 × 10 20 ions / cm 2 From approximately 4 × 10 20 ions / cm 2 Approximately 4 × 10 20 ions / cm 2 To approximately 5 × 10 20 ions / cm 2 or approximately 5 × 10 20 ions / cm 2 From approximately 6 × 10 20 ions / cm 2 Unbound by theory, approximately 1 × 10 20 ions / cm 2 To approximately 6 × 10 20 ions / cm 2 The dosage of free radicals can reduce the formation of defects, such as bubbles, in SiN-based dielectric films.

[0034] In some embodiments, free radicals activated in the RPS flow into the processing chamber at a flow rate between about 1 sccm and about 10,000 sccm (referred to as the "radical flux"). The composition of the formed SiN-based dielectric film can be adjusted by changing the composition of the reactive gas in the radical flux. To form nitrogen-containing films, such as SiON, SiCON, and SiN films, the reactive gas can be, for example, ammonia (NH3), hydrogen (H2), hydrazine (N2H4), nitrogen dioxide (NO2), or nitrogen (N2). Unbound from theory, when the reactive gas in the substrate processing region reacts with the transported dielectric precursor, Si-H and NH bonds (weaker bonds) partially break and are replaced by Si-N, Si-NH, and / or Si-NH2 bonds (stronger bonds) to form a SiN dielectric film.

[0035] The resulting silicon nitride (SiN)-based dielectric film can be exposed in a plasma chamber to a plasma containing light ions (e.g., ionized species with small atomic numbers in the periodic table), such as argon (e.g., Ar), nitrogen (e.g., N2), or fluorine-containing compounds (e.g., NF3), to facilitate selective etching at the top of the gaps. The plasma chamber is coupled to two power sources: an RF power source that controls the density of the ion flux (also known as the ion dose) via an induction coil, and a DC bias that controls the ion energy.

[0036] When operating at very high frequencies of about 20 MHz to about 30 MHz during plasma processing (e.g., about 20 MHz to about 22 MHz, about 22 MHz to about 24 MHz, about 24 MHz to about 26 MHz, about 26 MHz to about 28 MHz, or about 28 MHz to about 30 MHz), the RF source may have a power of about 40 watts (W) to about 60 W, for example, about 40 W to about 45 W, about 45 W to about 50 W, about 50 W to about 55 W, or about 55 W to about 60 W. In one embodiment, when operating at a frequency of about 27 MHz, the plasma may have a power of about 50 Hz.

[0037] During plasma processing, the DC bias voltage may have a voltage of about 0.1 kV to about 10 kV, about 0.1 kV to about 8 kV, about 0.1 kV to about 7 kV, about 0.1 kV to about 6 kV, about 0.1 kV to about 5 kV, about 0.1 kV to about 4 kV, about 0.1 kV to about 2 kV, about 0.1 kV to about 1 kV, about 0.1 kV to about 0.5 kV, about 1 kV to about 10 kV, about 1 kV to about 8 kV, about 1 kV to about 7 kV, about 1 kV to about 6 kV, about 1 kV to about 5 kV, about 1 kV to about 4 kV, about 3 kV to about 10 kV, about 3 kV to about 8 kV, about 3 kV to about 7 kV, about 3 kV to about 6 kV, or about 3 kV to about 5 kV.

[0038] In some embodiments, and at operation 109, a fluorinated compound (such as HF, NF3, or a combination thereof) may be introduced into the chamber to facilitate selective etching at the top of the gap. The fluorinated compound may be introduced at a flow rate of about 5 sccm to about 500 sccm, for example, about 5 sccm to about 50 sccm, about 50 sccm to about 100 sccm, about 100 sccm to about 300 sccm, or about 300 sccm to about 500 sccm. The fluorinated compound may be introduced at a pressure of about 0.1 tor to about 3 tor, for example, about 0.1 tor to about 1 tor, about 1 tor to about 2 tor, or about 2 tor to about 3 tor. The fluorinated compound may be introduced over a time period of about 1 s to about 60 s, for example, about 1 s to about 20 s, about 20 s to about 40 s, or about 40 s to about 60 s. Fluorine-containing compounds can be introduced at temperatures of about 400°C to about 600°C, for example, about 400°C to about 450°C, about 450°C to about 500°C, about 500°C to about 550°C, or about 550°C to about 600°C. In one embodiment, the temperature of about 400°C to about 600°C allows NF3 to selectively etch the SiN-based dielectric film at the top of the gap, while the SiN-based dielectric film at the bottom of the gap is minimally etched and / or not etched.

[0039] The formed silicon nitride (SiN)-based dielectric film can be exposed to a recycling process. The recycling process may include a hydrogen (e.g., H2) recycling process. In one embodiment, hydrogen may react with the plasma-treated SiN dielectric film to remove one or more defects and / or bubbles on the SiN dielectric film. In one embodiment, the recycling process may include exposing the plasma-treated SiN-based dielectric film to a recycling plasma. In the plasma chamber, the recycling plasma includes plasma containing one or more hydrogen ions (e.g., H2). The plasma contains hydrogen ions. Hydrogen ions can be introduced at a flow rate of about 500 sccm to about 2500 sccm, for example, about 500 sccm to about 1000 sccm, about 1000 sccm to about 1500 sccm, about 1500 sccm to about 2000 sccm, or about 2000 sccm to about 2500 sccm. Hydrogen ions can be introduced at a pressure of about 0.1 Torr to about 3 Torr, for example, about 0.1 Torr to about 1 Torr, about 1 Torr to about 2 Torr, or about 2 Torr to about 3 Torr. Hydrogen ions can be introduced over a time period of about 1 s to about 60 s, for example, about 1 s to about 20 s, about 20 s to about 40 s, or about 40 s to about 60 s. Hydrogen ions can be introduced at temperatures of about 400°C to about 600°C, for example, about 400°C to about 450°C, about 450°C to about 500°C, about 500°C to about 550°C, or about 550°C to about 600°C. In one embodiment, the hydrogen ions can react with SiF4 bonds formed as a result of NF3 plasma treatment, thereby forming Si-H bonds.

[0040] In one embodiment, exposure to recycled plasma bound to hydrogen ions can lead to further crosslinking between the formed Si-H bonds and the NH bonds in the formed SiN-based dielectric film. Unbound by theory, it is believed that the radicals of hydrogen ions activated in the plasma can substantially bombard the Si-H bonds within the SiN-based dielectric film, thereby disrupting the Si-H bonds and resulting in the formation of Si-N, Si-NH, and / or Si-NH2 bonds. The hydrogen ions travel through the formed SiN-based dielectric film to a selected depth without substantially damaging the formed SiN-based dielectric film. This treatment by the radicals of hydrogen ions makes it possible to remove one or more defects and / or bubbles formed by the NF3 plasma etching process, increasing homogeneity to a depth of 1 nm to 5 nm, such as 3 nm to 4 nm, without damaging the formed SiN-based dielectric film.

[0041] The plasma chamber is coupled to two power sources: an RF power source, which controls the density of ion flux (also known as ion dose) through an induction coil, and a DC bias voltage, which controls the ion energy.

[0042] When operating at very high frequencies of about 20 MHz to about 30 MHz during plasma processing (e.g., about 20 MHz to about 22 MHz, about 22 MHz to about 24 MHz, about 24 MHz to about 26 MHz, about 26 MHz to about 28 MHz, or about 28 MHz to about 30 MHz), the RF source may have a power of about 200 watts (W) to about 300 W, for example, about 200 W to about 220 W, about 220 W to about 240 W, about 240 W to about 260 W, about 260 W to about 280 W, or about 280 W to about 300 W. In one embodiment, when operating at a frequency of about 27 MHz, the plasma may have a power of about 240 Hz.

[0043] During plasma processing, the DC bias voltage may have a voltage of about 0.1 kV to about 10 kV, about 0.1 kV to about 8 kV, about 0.1 kV to about 7 kV, about 0.1 kV to about 6 kV, about 0.1 kV to about 5 kV, about 0.1 kV to about 4 kV, about 0.1 kV to about 2 kV, about 0.1 kV to about 1 kV, about 0.1 kV to about 0.5 kV, about 1 kV to about 10 kV, about 1 kV to about 8 kV, about 1 kV to about 7 kV, about 1 kV to about 6 kV, about 1 kV to about 5 kV, about 1 kV to about 4 kV, about 3 kV to about 10 kV, about 3 kV to about 8 kV, about 3 kV to about 7 kV, about 3 kV to about 6 kV, or about 3 kV to about 5 kV.

[0044] Typically, this set of operations (e.g., boxes 104-109) can be repeated multiple times to form a generally thicker membrane.

[0045] The implementation of deposition systems and technologies can be incorporated into larger manufacturing systems used to produce integrated circuit chips. Figure 2 A cluster tool 201 comprising processing chambers 208a-f is shown according to one embodiment. Figure 2 In this configuration, a pair of front-opening unified pods (FOUPs) 202 supply substrates (e.g., wafers with a diameter of 300 mm) received by robotic arm 104 and placed into low-voltage holding region 206. A second robotic arm 210 is used to transfer the substrates between low-voltage holding region 206 and processing chambers 208a-f.

[0046] Figure 3AThis is a schematic diagram of a processing chamber 300 having a chamber body 302 and a cover assembly 304 according to one embodiment. The cover assembly 304 typically includes a remote plasma source (RPS) 306, a cover 308, and a dual-channel nozzle (DCSH) 310. The RPS 306 processes a process precursor gas supplied from a process precursor gas source 312. The plasma formed in the RPS 306 is then delivered to a chamber plasma region 318 via a gas inlet assembly 314 and a baffle 316 coupled to the cover 308. A carrier gas (e.g., Ar, He) is delivered to the chamber plasma region 318. An insulating ring 320 is provided between the cover (i.e., the conductive top) 308 and the dual-channel nozzle (DCSH) 310, which allows an AC potential to be applied to the cover 308 relative to the DCSH 310.

[0047] The DCSH 310 is disposed between the chamber plasma region 318 and the substrate processing region 324, and allows free radicals activated in the plasma present in the chamber plasma region 318 to enter the substrate processing region 324 through multiple through-holes 326. The flow of free radicals (free radical flux) is controlled by... Figure 3A The solid arrow "A" in the diagram indicates this. The substrate 328 is disposed on the substrate support 330 within the substrate processing region 324. The DCSH 310 also has one or more hollow volumes 332 that can be filled with a dielectric precursor supplied from the precursor source 334. The dielectric precursor passes through the one or more hollow volumes 332 through the aperture 336 and enters the substrate processing region 324, bypassing the chamber plasma region 318. The flow of the dielectric precursor is... Figure 3A The dashed arrows indicate this. The exhaust ring 338 is used to uniformly evacuate the substrate processing region 324 using an exhaust pump 340. The DCSH 310 may be thicker than the minimum diameter of the through-hole 326. The minimum diameter of the through-hole 326 can be limited by forming a larger diameter portion of the through-hole 326 that partially passes through the DCSH 310 to maintain free radical flux flowing from the chamber plasma region 318 into the substrate processing region 324. In some embodiments, the minimum diameter of the through-hole 326 may be on the same order of magnitude as or smaller than the minimum diameter of the through-hole 326.

[0048] In some implementations... Figure 2 A pair of processing chambers (e.g., 208c-d) (referred to as a dual chamber) can be used to deposit dielectric precursors on a substrate. Each of the processing chambers (e.g., 208c-d) may have Figure 3A The cross-sectional structure of the processing chamber 300 is depicted. The flow rate of each channel of the aforementioned DCSH corresponds to the flow rate of each entering the chamber (e.g., 208c-d) through the corresponding DCSH 310.

[0049] Figure 3BThis is a schematic bottom view of a DCSH 310 according to one embodiment. The DCSH 310 can deliver free radical flux and carrier gas present in the chamber plasma region 318 through the through-hole 326.

[0050] In some embodiments, the number of through holes 326 can be from about 60 to about 2000. The through holes 326 can be circular or of various shapes. In some embodiments, the minimum diameter of the through holes 326 can be from about 0.5 mm to about 20 mm, such as from about 1 mm to about 6 mm. The cross-sectional shape of the through holes 326 can be conical, cylindrical, or a combination of both. In some embodiments, several vias 336 can be used to introduce dielectric precursors into the substrate processing area 324, and can be from about 100 to about 5000 vias or from about 500 to about 2000 vias. The diameter of the vias 336 can be from about 0.1 mm to about 2 mm.

[0051] Figure 4 This is a schematic diagram of a plasma chamber 400 having a chamber body 402 and a cover assembly 404 according to one embodiment. The cover assembly 404 includes a gas delivery assembly 406 and a cover 408. The cover 408 has an opening 410 to allow one or more process precursor gases to enter. The gas delivery assembly 406 is disposed above the cover 408 through the opening 410. The gas delivery assembly 406 is connected to a gas source 412 through a gas inlet 414 to supply one or more process precursor gases to a substrate processing region 424. A substrate 428 is disposed on a substrate support 430 within the substrate processing region 424 and coupled to a bias power supply (not shown). One or more process precursor gases can exit the substrate processing region 424 using an exhaust ring 438 and an exhaust pump 440.

[0052] In the cover assembly 404, an inner coil 442, an intermediate coil 444, and an outer coil 446 are disposed on the cover 408. The inner coil 442 and the outer coil 446 are coupled to an RF power supply 448 via a matching circuit 450. The power applied from the RF power supply 448 to the outer coil 446 is inductively coupled through the cover 408 to generate plasma within the substrate processing region 424 from the processing precursor gas supplied from the gas source 412. The RF power supply 448 can provide currents of different frequencies to control the plasma density (i.e., the number of ions per cc) in the plasma, and thus control the ion flux density (ions / cm³). 2 (seconds). The bias power supply controls the voltage between the substrate 428 and the plasma, and thus controls the energy and directionality of the ions. Therefore, both the ion flux and the ion energy can be controlled independently.

[0053] The heater assembly 452 may be disposed above the cover 408. The heater assembly 452 may be secured to the cover 408 by clamping members 454 and 456.

[0054] The surface of the substrate can be maintained at a temperature of approximately 100°C to approximately 500°C, for example, approximately 450°C. The pressure in the plasma chamber can be maintained at approximately 5 mTorr to approximately 500 mTorr.

[0055] In general, various embodiments of this disclosure allow for selective etching of the top of the gap without etching the bottom, or limited etching of the bottom of the gap, thereby increasing the uniformity of the dielectric material in the gap. Furthermore, a recycling process can be used to remove defects (e.g., blistering) to provide a uniform dielectric material layer in the gap. Additionally, a reduction in dielectric material buildup can be achieved by nitriding a monolayer of silicon oxide to form silicon nitride without creating defects and / or altering the quality of the silicon nitride film.

[0056] Example 1

[0057] A reference SiN-based dielectric film was compared with a SiN-based dielectric film produced using the NF3 thermal etching process. Samples were analyzed at critical dimensions of 25 nm, 35 nm, and 50 nm. The film was prepared by depositing an amorphous silicon dioxide layer by flowing 10 sccm of SiH4 and 2900 sccm of H2 at a pressure of 0.8 Torr for 39 seconds. The spacing was 1600 mil. The power was 60 W at 27 MHz. 4500 sccm of Ar and 600 sccm of H2 were introduced into the amorphous silicon dioxide layer at a pressure of 2.1 Torr for 10 seconds. The spacing was 555 mil, and the power was 60 W. The example film was thermally etched using the NF3 process by flowing 2000 sccm of NF3, 4000 sccm of clean Ar (argon gas flowing from a remote plasma source), and 1000 sccm of process Ar (argon gas flowing from a process gas panel) at a pressure of 5 Torr for 8 seconds. The power was 0 W and the spacing was 300 mil. The film was then exposed to 2500 sccm N2 for 60 seconds at a pressure of 5.5 Torr. The power was 1000 W and the spacing was 555 mil. The use of NF3 thermal etching allowed for the production of uniform Si-NH dielectric films with finite defects, such as... Figure 5 As shown. Furthermore, compared to conventional SiN films, SiN films offer similar quality, reducing and / or eliminating the need for plasma etching processes after nitriding.

[0058] Example 2

[0059] A reference SiN-based dielectric film was compared with a SiN-based dielectric film produced using a plasma NF3 etching process. Samples were analyzed at critical dimensions of 25 nm, 35 nm, and 50 nm. The film was prepared by depositing an amorphous silicon dioxide layer by flowing 10 sccm of SiH4 and 2900 sccm of H2 at a pressure of 0.8 Torr for 39 seconds. The spacing was 1600 mil. The power was 60 W at 27 MHz. 4500 sccm of Ar and 600 sccm of H2 were introduced into the amorphous silicon dioxide layer at a pressure of 2.1 Torr for 10 seconds. The spacing was 555 mil, and the power was 60 W. The film was then exposed to 2500 sccm of N2 at a pressure of 5.5 Torr for 60 seconds. The power was 1000 W, and the spacing was 555 mil.

[0060] The Si-N based dielectric film was then etched using plasma in the presence of NF3. NF3 was introduced into the plasma operating at 50 W and 27 MHz at a flow rate of 15 sccm for 15 seconds. The pressure was 1 Torr and the spacing was 300 mil. Argon carrier gas was introduced at 300 sccm. The temperature was 450°C. The Si-N based dielectric film was then processed according to a recycling process. Hydrogen was introduced into the plasma operating at 250 W and 27 MHz at a flow rate of 2500 sccm for 20 seconds. The pressure was 2.5 Torr and the spacing was 555 mil. Compared to bottom etching, the use of plasma NF3 etching allowed for selective top etching because the bottom-to-top ratio increased from 0.9 to 3.5, promoting a uniform Si-N based dielectric film on the substrate features, such as... Figure 6 As shown.

[0061] Example 3

[0062] Several defects present in SiN-based dielectric films were analyzed. First and second SiN-based dielectric films were produced using a plasma NF3 etching process. The first film served as a reference, while the second film was processed using a recovery process that introduced H2 at a flow rate of 2500 sccm, while operating the plasma at 250 W and 27 MHz. The pressure was 2.5 Torr, the dose time was 20 seconds, and the spacing was 555 mil. The first film had a defect overload, for example, greater than 100,000 defects. Alternatively, the second film contained only 11 defects present in the SiN-based dielectric film. Unbound from theoretical constraints, the recovery process, including hydrogen ion removal, reduced the number of defects present in the SiN-based dielectric film, improving film quality.

[0063] Example 4

[0064] A first wet etch rate and a second wet etch rate were determined for a conventional SiN-based dielectric film, a SiN-based dielectric film produced by plasma NF3 etching, and a SiN-based dielectric film produced by plasma NF3 etching after a recycling process. The first wet etch rate was determined on the surface of the SiN-based dielectric film, and the second wet etch rate was determined at the location of the SiN-based dielectric film below the surface after the first wet etch rate. Due to the change in film surface quality after exposure to NF3, the SiN-based dielectric film produced by plasma NF3 etching exhibited the highest wet etch rate. However, after a recycling process of the dielectric film, the wet etch rate returned to the wet etch rate of a conventional SiN-based dielectric film, such as... Figure 7 As shown.

[0065] While the foregoing describes embodiments of this disclosure, other and further embodiments may be designed without departing from the basic scope of this disclosure, the scope of which is determined by the following claims. All documents described herein are incorporated by reference, including any priority documents and / or test procedures, provided they do not contradict this document. As will be apparent from the foregoing general description and detailed description, various modifications may be made to this disclosure without departing from its spirit and scope, although the form of this disclosure has been shown and described. Therefore, this disclosure is not intended to be limited thereto. Similarly, for purposes of U.S. law, the term “comprising” is considered synonymous with the term “including.” Likewise, whenever a component, element, or group of elements is preceded by the transitional phrase “comprising,” it should be understood that the same component or group of elements having the transitional phrases “substantially constitutes,” “consisting of,” “selected from a group of,” or “is” are considered before the description of the component, element, or such elements, and vice versa. As used herein, the term “about” means a difference of + / - 10% from the nominal value. It should be understood that such differences may be included in any of the values ​​provided in this article.

[0066] Certain embodiments and features have been described using a set of upper and lower numerical limits. It should be understood that, unless otherwise stated, a range is considered that includes any combination of two values ​​(e.g., any lower value combined with any higher value, any two lower values ​​combined, and / or any two higher values ​​combined). Certain lower, upper, and range limits appear in one or more of the preceding claims.

Claims

1. A method for forming a silicon nitride-based dielectric film, the method comprising: The substrate is supplied to the processing chamber; An amorphous silicon dioxide layer is formed on the surface of the substrate by flowing dielectric precursor and carrier gas on the substrate. A modified amorphous silicon dioxide layer is formed by allowing the reactive gas to flow into the processing chamber. The modified amorphous silicon dioxide layer is subjected to a thermal etching process by allowing a fluorine-containing compound to flow at a temperature of about 400°C to about 600°C; and A silicon nitride-based dielectric film is formed by reacting the modified amorphous silicon dioxide layer with one or more free radicals generated by a remote plasma source.

2. The method of claim 1, wherein the flow rate ratio of the dielectric precursor to the carrier gas is about 1:100 to about 1:

500.

3. The method of claim 1, wherein the reactant gas comprises H2.

4. The method of claim 1, wherein the fluorinated compound comprises NF3.

5. The method of claim 1, wherein the fluorinated compound is flowed at a flow rate of about 500 sccm to about 3000 sccm.

6. The method of claim 1, wherein the one or more free radicals comprise hydrogen free radicals.

7. The method of claim 6, wherein the energy of the hydrogen radical is from about 25 eV to about 70 eV.

8. The method of claim 6, wherein the dose of the hydrogen radical is about 1 × 10⁻⁶. 20 ions / cm 2 To approximately 6 × 10 20 ions / cm 2 .

9. A method for forming a silicon nitride-based dielectric film, the method comprising: The substrate is supplied to the processing chamber; An amorphous silicon dioxide layer is formed on the surface of the substrate by flowing dielectric precursor and carrier gas on the substrate. A modified amorphous silicon dioxide layer is formed by allowing the reactive gas to flow into the processing chamber. A silicon nitride-based dielectric film is formed by reacting the modified amorphous silicon dioxide layer with one or more free radicals generated by a remote plasma source; and A silicon nitride-based dielectric film is formed by introducing a fluorine-containing compound into the processing chamber in the presence of plasma.

10. The method of claim 9, wherein the flow rate ratio of the dielectric precursor to the carrier gas is about 1:100 to about 1:

500.

11. The method of claim 9, wherein the reactant gas comprises H2.

12. The method of claim 9, wherein the fluorinated compound comprises NF3.

13. The method of claim 9, wherein the fluorinated compound is flowed at a flow rate of about 5 sccm to about 500 sccm.

14. The method of claim 9, wherein the plasma comprises argon plasma.

15. The method of claim 14, wherein when operating at a frequency of about 20 MHz to about 30 MHz, the plasma is generated at a power of about 40 watts to about 60 watts.

16. A method for forming a silicon nitride-based dielectric film, the method comprising: An amorphous silicon dioxide layer is formed on the surface of the substrate by allowing the dielectric precursor and carrier gas to flow on the substrate. A modified amorphous silicon dioxide layer is formed by allowing the reactive gas to flow into the processing chamber. A silicon nitride-based dielectric film is formed by reacting the modified amorphous silicon dioxide layer with one or more free radicals. By allowing a fluorine-containing compound to flow into the processing chamber in the presence of plasma, an etched silicon nitride-based dielectric film is formed; and The hydrogen recovery process involves exposing the etched silicon nitride-based dielectric film to the processing chamber.

17. The method of claim 16, wherein the flow rate ratio of the dielectric precursor to the carrier gas is about 1:100 to about 1:

500.

18. The method of claim 16, wherein the hydrogen recovery process comprises a recovery plasma configured to generate one or more hydrogen ions.

19. The method of claim 18, wherein the one or more hydrogen ions are introduced into the processing chamber at a flow rate of about 500 sccm to about 2500 sccm.

20. The method of claim 18, wherein when operating at a frequency of about 20 MHz to about 30 MHz, the plasma is generated at a power of about 40 watts to about 60 watts.

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