Flowable Film Formation and Processing

Abstract

An exemplary processing method may include forming a plasma of a silicon-containing precursor. The method may include depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor. The semiconductor substrate may define a feature in the semiconductor substrate. The method may include forming a plasma of a hydrogen-containing precursor in a processing region of a semiconductor processing chamber. A bias power may be applied to the substrate support from a bias power supply. The method may include etching the flowable film from sidewalls of the feature in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor. The method may include densifying the flowable film remaining in the feature defined in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. patent application Ser. No. 16 / 932,801, filed July 19, 2020, entitled "FLOWABLE FILM FORMATION AND TREATMENTS," which is incorporated by reference in its entirety.

[0002]

[0002] The present technology relates to semiconductor processing. More particularly, the present technology relates to methods of depositing, etching, and transforming materials, including flowable films. [Background technology]

[0003]

[0003] Integrated circuits are made possible by processes that create intricately patterned layers of material on substrate surfaces. Creating patterned materials on substrates requires controlled methods for forming and removing exposed material. As devices become increasingly miniaturized, material formation can impact subsequent operations. For example, in gap-fill operations, material may be formed or deposited to fill trenches or other features formed on semiconductor substrates. These fill operations can be challenging because the features may be characterized by high aspect ratios and reduced critical dimensions. For example, because deposition may occur on top of the feature and along the sidewalls of the feature, continued deposition can pinch off the feature, including between the sidewalls within the feature, creating voids within the feature. This can impact device performance and subsequent processing operations.

[0004]

[0004] Therefore, there is a need for improved systems and methods that can be used to manufacture high quality devices and structures. These and other needs are addressed by the present technology. Summary of the Invention

[0005] An exemplary processing method may include forming a plasma of a silicon-containing precursor. The method may include depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor. The semiconductor substrate may be contained in a processing region of a semiconductor processing chamber. The semiconductor substrate may define a feature in the semiconductor substrate. The processing region may be at least partially defined between a faceplate and a substrate support on which the semiconductor substrate rests. The method may include forming a plasma of a hydrogen-containing precursor in the processing region of the semiconductor processing chamber. The plasma of the hydrogen-containing precursor may be formed at a first power level from a plasma power source. A bias power may be applied to the substrate support from the bias power source at a second power level lower than the first power level. The method may include etching the flowable film from sidewalls of features in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor. The method may include densifying the flowable film remaining in the features defined in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor.

[0006] In some embodiments, the features in the semiconductor substrate may be characterized by an aspect ratio of about 5:1 or greater. The features may be characterized by a width across the feature of about 10 nm or less. The bias power supply may be operated in a pulsed mode at a pulse frequency of about 1 kHz or less. The plasma power supply may be operated in a continuous wave mode while the bias power supply is operated in a pulsed mode. The bias power supply may be operated at a duty cycle of about 75% or less. The bias power supply may be engaged following engagement of the plasma power supply. Densifying may include reducing the hydrogen content of the flowable film to about 30 atomic % or less. The method may also include forming a plasma of a conversion precursor following densifying. The method may include converting the flowable film to a modified film. The conversion precursor may be or may include a nitrogen-containing precursor, an oxygen-containing precursor, or a carbon-containing precursor. The method may be repeated for a second cycle. The temperature of the semiconductor substrate may be maintained at a temperature of about 0° C. or less during the method.

[0007] Some embodiments of the present technology may include a processing method. The method may include forming a plasma of a silicon-containing precursor. The method may include depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor. The semiconductor substrate may be contained in a processing region of a semiconductor processing chamber. The semiconductor substrate may define a feature in the semiconductor substrate. The method may include forming a plasma of a hydrogen-containing precursor in the processing region of the semiconductor processing chamber. The plasma of the hydrogen-containing precursor may be formed at a first power level of a plasma power source. A bias power may be applied to the plasma of the hydrogen-containing precursor from the bias power source at a second power level. The method may include etching the flowable film from sidewalls of the feature defined in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor. The method may include densifying the flowable film remaining in the feature defined in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor.

[0008] In some embodiments, the plasma power supply providing the first power level can operate continuously while the bias power supply can operate in a pulsed mode at a frequency of about 1 kHz or less. The bias power supply can operate at a duty cycle of about 50% or less. The etching can completely remove the flowable film from the sidewalls of the feature above a base fill of the feature. The method can include forming a plasma of a conversion precursor following densification. The method can include converting the flowable film to a modified film. The conversion precursor can be or include a nitrogen-containing precursor, an oxygen-containing precursor, or a carbon-containing precursor. The modified film can be or include silicon nitride, silicon oxide, or silicon carbide.

[0009] Some embodiments of the present technology include a processing method. The method may include forming a plasma of a silicon-containing precursor. The method may include depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor. The semiconductor substrate may be contained in a processing region of a semiconductor processing chamber. The semiconductor substrate may define a feature in the semiconductor substrate. The method may include forming a plasma of a hydrogen-containing precursor in the processing region of the semiconductor processing chamber. The method may include etching the flowable film from sidewalls of the feature defined in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor. The method may include densifying the flowable film remaining in the feature defined in the semiconductor substrate using plasma effluents of the hydrogen-containing precursor. The method may include forming a plasma of a converting precursor. The method may include converting the flowable film to a modified film. In some embodiments, the modified film may be or include silicon and one or more of nitrogen, oxygen, or carbon.

[0010]

[0010] Such techniques may offer numerous advantages over conventional systems and techniques. For example, by performing a curing or processing operation according to embodiments of the present technology, sidewall coverage may be limited or controlled, thereby limiting the formation of voids in small features. Additionally, performing a converting operation following the curing process may further prevent the formation of voids by limiting the effects of film expansion. These and other embodiments, along with their many advantages and features, are described in more detail below in conjunction with the description and accompanying drawings.

[0011]

[0011] A further understanding of the nature and advantages of the disclosed technology may be realized by reference to the remaining portions of the specification and the drawings. [Brief explanation of the drawings]

[0012] [Figure 1] 1 shows a schematic cross-sectional view of an exemplary processing chamber in accordance with some embodiments of the present technique; [Figure 2] 1 illustrates exemplary steps in a processing method according to some embodiments of the present technique. [Figure 3] 1A-C show schematic cross-sectional views of a substrate during processing, according to some embodiments of the present technique. DETAILED DESCRIPTION OF THE INVENTION

[0013]

[0015] Some drawings are included as schematic diagrams. It should be understood that the drawings are for illustrative purposes and should not be considered to scale unless expressly stated to be to scale. Furthermore, as schematic diagrams, the drawings are provided to aid in understanding and may not include all aspects or information compared to realistic depictions and may include exaggerated material for illustrative purposes.

[0014]

[0016] In the accompanying drawings, similar components and / or features may have the same reference numerals. Furthermore, various components of the same type may be distinguished according to the reference numeral, with a letter distinguishing between the similar components. When only a first reference numeral is used herein, the description is applicable to any one of the similar components having the same first reference numeral, regardless of the letter.

[0015]

[0017] Amorphous silicon can be used in semiconductor device fabrication for many structures and processes, including as a sacrificial material, e.g., as a dummy gate material, or as a trench fill material. In gap-fill processes, some processes utilize a flowable film formed under process conditions to limit deposition conformality, allowing the deposited material to better fill features on the substrate. Flowable silicon materials can be characterized by a relatively high amount of hydrogen and have a lower density than other formed films. As a result, subsequent processing steps can be performed to harden the resulting film. Conventional techniques utilize UV ​​curing processes to remove hydrogen and treat the film. However, UV curing can cause significant film shrinkage, which can create voids in the structure as well as stress the feature.

[0016]

[0018] As feature sizes continue to shrink, flowable films can become a challenge for narrow features, which may be further characterized by higher aspect ratios. For example, deposition on the sidewalls of a feature can more easily result in pinching of the feature, and smaller feature sizes can further restrict further flow into the feature and create voids. Furthermore, for processes in which conversion of amorphous silicon may be performed, expansion of the sidewall material during conversion can further restrict access within the feature. The present technique can overcome these limitations by performing an etch of the formed film during a curing step. This can limit or prevent sidewall coverage during trench fill, enabling an improved fill process. Additionally, a conversion step can be performed after curing, further reducing flow restrictions within the feature. After describing general aspects of a chamber according to some embodiments of the present technique in which the plasma processing steps described below may be performed, specific methodologies can be described. It is understood that the described technique is not intended to be limited to the specific films, chambers, or processes described, as the described technique can be used to improve numerous film formation processes and may be applicable to a variety of processing chambers and processes.

[0017]

[0019] FIG. 1 illustrates a cross-sectional view of an exemplary processing chamber 100 in accordance with some embodiments of the present technique. This diagram may provide an overview of a system incorporating one or more aspects of the present technique and / or capable of performing one or more deposition or other processing steps in accordance with embodiments of the present technique. Additional details of the chamber 100 or the method performed therein may be further described below. While the chamber 100 may be utilized to form a film layer in accordance with some embodiments of the present technique, it should be understood that the method may similarly be performed in any chamber in which film formation may occur. The processing chamber 100 may include a chamber body 102, a substrate support 104 disposed within the chamber body 102, and a lid assembly 106 coupled to the chamber body 102 and enclosing the substrate support 104 within a processing space 120. A substrate 103 may be provided to the processing space 120 through an opening 126, which may conventionally be sealed for processing using a slit valve or door. The substrate 103 may be positioned on a surface 105 of the substrate support during processing. The substrate support 104 may be rotatable, as indicated by arrow 145, along an axis 147 about which the shaft 144 of the substrate support 104 may lie. Alternatively, the substrate support 104 may be elevated for rotation as needed during the deposition process.

[0018]

[0020] A plasma profile modulator 111 may be disposed within the processing chamber 100 to control plasma distribution across a substrate 103 disposed on a substrate support 104. The plasma profile modulator 111 may include a first electrode 108 that may be disposed adjacent to the chamber body 102 and may separate the chamber body 102 from other components of the lid assembly 106. The first electrode 108 may be part of the lid assembly 106 or may be a separate sidewall electrode. The first electrode 108 may be an annular or ring-shaped member and may be a ring electrode. The first electrode 108 may be a continuous loop along the periphery of the processing chamber 100 surrounding the processing space 120, or may be discontinuous at selected locations as desired. The first electrode 108 may also be a perforated electrode, such as a perforated ring or mesh electrode, or a plate electrode, such as a secondary gas distributor.

[0019]

[0021] The one or more isolators 110 a, 110 b may be a dielectric material such as a ceramic or a metal oxide, e.g., aluminum oxide and / or aluminum nitride, and may contact the first electrode 108 and electrically and thermally isolate the first electrode 108 from the gas distributor 112 and the chamber body 102. The gas distributor 112 may define an aperture 118 for distributing process precursors into the processing space 120. The gas distributor 112 may be connected to a first power source 142, such as an RF generator, an RF power supply, a DC power supply, a pulsed DC power supply, a pulsed RF power supply, or any other power source that may be connected to a processing chamber. In some embodiments, the first power source 142 may be an RF power supply.

[0020]

[0022] The gas distributor 112 may be a conductive gas distributor or a non-conductive gas distributor. The gas distributor 112 may also be formed from conductive and non-conductive components. For example, the body of the gas distributor 112 may be conductive, but the face plate of the gas distributor 112 may be non-conductive. The gas distributor 112 may be powered, such as by a first power source 142 as shown in FIG. 1, or the gas distributor 112 may be connected to ground in some embodiments.

[0021]

[0023] The first electrode 108 may be connected to a first tuned circuit 128 that may control the ground path of the processing chamber 100. The first tuned circuit 128 may include a first electronic sensor 130 and a first electronic controller 134. The first electronic controller 134 may be or include a variable capacitor or other circuit element. The first tuned circuit 128 may be or include one or more inductors 132. The first tuned circuit 128 may be any circuit that allows for a variable or controllable impedance under plasma conditions present in the processing space 120 during processing. In some illustrated embodiments, the first tuned circuit 128 may include a first circuit leg and a second circuit leg connected in parallel between ground and the first electronic sensor 130. The first circuit leg may include a first inductor 132A. The second circuit leg may include a second inductor 132B connected in series with the first electronic controller 134. The second inductor 132B can be disposed between the first electronic controller 134 and a node coupling both the first and second circuit legs to the first electronic sensor 130. The first electronic sensor 130 can be a voltage or current sensor and can be connected to the first electronic controller 134 to allow some degree of closed-loop control of the plasma conditions within the process space 120.

[0022]

[0024] The second electrode 122 may be connected to the substrate support 104. The second electrode 122 may be integrated into the substrate support 104 or connected to a surface of the substrate support 104. The second electrode 122 may be a plate, a perforated plate, a mesh, a wire screen, or any other distributed configuration of conductive elements. The second electrode 122 may be a tuning electrode and may be connected to a second tuning circuit 136, for example, by a conduit 146 (e.g., a cable having a selected resistance, such as 50 ohms) disposed within a shaft 144 of the substrate support 104. The second tuning circuit 136 may include a second electronic sensor 138 and a second electronic controller 140, which may be a second variable capacitor. The second electronic sensor 138 may be a voltage sensor or a current sensor and may be connected to the second electronic controller 140 to provide further control over the plasma conditions in the process space 120.

[0023]

[0025] A third electrode 124, which may be a bias electrode and / or an electrostatic chucking electrode, may be coupled to the substrate support 104. The third electrode is connected to a second power source 150 through a filter 148, which may be an impedance matching circuit. The second power source 150 may be DC power, pulsed DC power, RF bias power, a pulsed RF source or bias power, or a combination of these or other power sources. In some embodiments, the second power source 150 may be RF bias power.

[0024]

[0026] The lid assembly 106 and substrate support 104 of FIG. 1 can be used with any processing chamber for plasma or thermal processing. During operation, the processing chamber 100 can perform real-time control of plasma conditions within the processing space 120. The substrate 103 is placed on the substrate support 104, and process gases can flow through the lid assembly 106 using the inlet 114 according to any desired flow scheme. The gases can be exhausted from the processing chamber 100 through the outlet 152. Power can be connected to the gas distributor 112 to establish a plasma within the processing space 120. In some embodiments, the substrate can be electrically biased using the third electrode 124.

[0025]

[0027] Upon exciting a plasma in the process space 120, a potential difference may be established between the plasma and the first electrode 108. A potential difference may also be established between the plasma and the second electrode 122. The electronic controllers 134 and 140 may then be used to adjust the flow characteristics of the ground paths represented by the two tuned circuits 128 and 136. Set points may be provided to the first tuned circuit 128 and the second tuned circuit 136 to provide independent control of the deposition rate and the center-to-edge plasma density uniformity. In embodiments in which both electronic controllers may be variable capacitors, electronic sensors may independently adjust the variable capacitors to maximize the deposition rate and minimize thickness non-uniformity.

[0026]

[0028] Each of the tuning circuits 128 and 136 may have a variable impedance that can be adjusted using the respective electronic controllers 134 and 140. If the electronic controllers 134 and 140 are variable capacitors, the capacitance range of each of the variable capacitors and the inductance of the first inductor 132A and the second inductor 132B may be selected to provide an impedance range. This range depends on the frequency and voltage characteristics of the plasma and may have a minimum value for the capacitance range of each variable capacitor. Thus, when the capacitance of the first electronic controller 134 is at its minimum or maximum, the impedance of the first tuning circuit 128 may be high. This results in a plasma shape with minimum aerial or lateral coverage above the substrate support. When the capacitance of the first electronic controller 134 reaches a value that minimizes the impedance of the first tuning circuit 128, the aerial coverage of the plasma may grow to its maximum, thereby effectively covering the entire working area of ​​the substrate support 104. If the capacitance of the first electronic controller 134 deviates from the minimum impedance setting, the plasma shape may contract from the chamber walls, reducing the air coverage of the substrate support. The second electronic controller 140 may have a similar effect, increasing or decreasing the air coverage of the plasma above the substrate support as the capacitance of the second electronic controller 140 changes.

[0027]

[0029] Electronic sensors 130 and 138 may be used to tune the respective circuits 128, 136 in a closed loop. Depending on the type of sensor used, a set point for current or voltage may be attached to each sensor. The sensors may be provided with control software that determines adjustments to the respective electronic controllers 134, 140 to minimize deviations from the set point. As a result, the shape of the plasma may be selected and dynamically controlled during processing. While the above description is based on the electronic controllers 134, 140 being variable capacitors, it should be understood that any electronic component having an adjustable characteristic may be used to provide the tuning circuits 128 and 136 with an adjustable impedance.

[0028]

[0030] In some embodiments of the present technology, the processing chamber 100 may be utilized for processing methods that may include forming, etching, or transforming materials for semiconductor structures. The described chamber should not be considered limiting, and it should be understood that any chamber that can be configured to perform the operations as described may similarly be used. FIG. 2 illustrates exemplary steps in a processing method 200 in accordance with some embodiments of the present technology. The method may be performed in a variety of processing chambers, including the processing chamber 100 described above, and on one or more mainframes or tools. Method 200 may include several optional steps that may or may not be specifically associated with some embodiments of the method in accordance with the present technology. For example, many of the steps are described to provide a broader range of structure formation, but may be performed by alternative methodologies that are not critical to the present technology or will be readily understood. Method 200 may describe the steps shown generally in FIGS. 3A-3C, examples of which will be described in conjunction with the steps of method 200. It should be understood that only partial schematic views are shown, and that the substrate may include any number of additional materials and features having various properties and aspects as illustrated in the figures.

[0029]

[0031] Method 200 may include additional steps prior to the initiation of the listed steps. For example, the additional processing steps may include forming structures on a semiconductor substrate, which may include both the formation and removal of materials. For example, a transistor structure, a memory structure, or any other structure may be formed. The prior processing steps may be performed in the chamber in which method 200 is performed, or processing may be performed in one or more other processing chambers before providing a substrate to one or more semiconductor processing chambers in which method 200 is performed. Nevertheless, method 200 may optionally include providing a semiconductor substrate to a processing region of a semiconductor processing chamber, such as processing chamber 100 described above, or to another chamber that may include components such as those described above. The substrate may be deposited on a substrate support, which may be a pedestal, such as substrate support 104, and which may be present in the processing region of a chamber, such as processing space 120 described above.

[0030]

[0032] The substrate on which some steps have been performed is substrate 305 of structure 300, which may represent a partial view of a substrate on which semiconductor processing may be performed. It should be understood that structure 300 may show only some of the top layers of processing to illustrate aspects of the present technology. Substrate 305 may include a material on which one or more features 310 may be formed. Substrate 305 may be any number of materials used in semiconductor processing. The substrate material may be or include silicon, germanium, a dielectric material including silicon oxide or silicon nitride, a metallic material, or any combination of these materials, and may be a material formed in substrate 305 or structure 300. Feature 310 may be characterized by any shape or configuration according to the present technology. In some embodiments, feature may be or include a trench structure or an opening formed in substrate 305.

[0031]

[0033] While the feature 310 can be characterized by any shape or size, in some embodiments, the feature 310 can be characterized by a higher aspect ratio, or ratio of the depth of the feature to the width across the feature. For example, in some embodiments, the feature 310 can be characterized by an aspect ratio of about 5:1 or greater, and can be characterized by aspect ratios of about 10:1 or greater, about 15:1 or greater, about 20:1 or greater, about 25:1 or greater, about 30:1 or greater, about 40:1 or greater, about 50:1 or greater, or greater. Additionally, the feature can be characterized by a narrow width or diameter across the feature, including between two sidewalls, such as a dimension of about 20 nm or less, and can be characterized by a width across the feature of about 15 nm or less, about 12 nm or less, about 10 nm or less, about 9 nm or less, about 8 nm or less, about 7 nm or less, about 6 nm or less, less than about 5 nm or less, or less.

[0032]

[0034] In some embodiments, method 200 may include optional processing steps, such as pre-treatment, that may be performed to prepare the surface of substrate 305 for deposition. Once prepared, method 200 may include supplying one or more precursors to a processing region of a semiconductor processing chamber containing structure 300. The precursors may include one or more silicon-containing precursors and one or more diluent or carrier gases, such as an inert gas or other gases, supplied with the silicon-containing precursors. In step 205, a plasma may be formed from the deposition precursors, including the silicon-containing precursors. The plasma may be formed in the processing region, which may allow a deposited material to be deposited on the substrate. For example, in some embodiments, a capacitively coupled plasma may be formed in the processing region by applying plasma power to a faceplate as described above.

[0033]

[0035] In step 210, a silicon-containing material may be deposited on a substrate from plasma effluents of a silicon-containing precursor. The material, in some embodiments, is a flowable silicon-containing material and may be or include amorphous silicon. The deposited material may at least partially flow into a feature on the substrate to provide bottom-up gap filling. As shown in FIG. 3A, material 315 may be deposited on a substrate 305 and flow into a trench or feature 310. As shown, the deposited material 315 may flow to the bottom of the feature, but some material may remain on the sidewalls of the substrate as shown. While the amount deposited may be relatively small, the material remaining on the sidewalls may restrict subsequent flow. Additionally, if a conventional conversion, such as conversion to silicon nitride, is performed on the deposited material, the conversion will involve film expansion. In the case of features with reduced dimensions, the residual material formed on the sidewall may convert and expand outward toward the opposite sidewall. This can cause pinching of the feature and the formation of voids within the feature.

[0034]

[0036] The power applied during deposition may be a low-power plasma to limit dissociation and maintain hydrogen incorporation into the deposited material. This incorporation may contribute to the flowability of the deposited material. Thus, in some embodiments, the plasma power source may provide a plasma power of about 300 W or less to the faceplate, and may provide a power of about 250 W or less, about 200 W or less, about 150 W or less, about 100 W or less, about 50 W or less, or less.

[0035]

[0037] Following a certain amount of deposition, in some embodiments of the present technique, a treatment or cure process configured to etch back the formed material may be formed. This process may be performed in the same chamber as the deposition and may be performed in a cyclical process to fill the feature. In some embodiments, the flow of the silicon-containing precursor may be stopped and the processing region may be purged. Following the purge, a hydrogen-containing precursor may be flowed into the processing region of the processing chamber. In step 215, a processing plasma is formed, which may be a capacitively coupled plasma formed in the processing region, although in some embodiments, an inductively coupled plasma may be applied as well. The deposition plasma formed is formed by applying plasma power to a faceplate or showerhead; in some embodiments, no other power source may be engaged.

[0036]

[0038] During the processing step, an additional power supply may be engaged and coupled to the substrate support, as described above, to provide a bias to the plasma generated above the substrate. This may attract plasma effluents to the substrate, which may bombard the film and cause densification of the deposited material. While any hydrogen-containing material may be used, in some embodiments, diatomic hydrogen may be used as the hydrogen-containing precursor, along with one or more additional precursors, to generate the processing plasma. Hydrogen radicals and ions may easily penetrate the material formed within the trench, releasing incorporated hydrogen from the film and causing densification. The applied bias power may be relatively low to limit sputtering of the generated film as well as any potential damage to the structure. To limit sputtering of the deposited film, the amount of heavier material supplied to form the plasma may be reduced as well. Additionally, by adjusting the applied source power and bias power, an etching step may be performed to reduce the sidewall coverage of the deposited material.

[0037]

[0039] Hydrogen, or any other hydrogen-containing material, may be used to generate a plasma in the processing region by supplying power from a plasma power source to a faceplate. In some embodiments, the plasma power may be greater than the plasma power used during deposition. For example, the supplied plasma power may be about 100 W or greater, about 200 W or greater, about 300 W or greater, about 400 W or greater, about 500 W or greater, about 600 W or greater, or greater. By increasing the plasma power during processing plasma formation, a greater amount of plasma effluents may be generated. Additionally, the bias power may be adjusted. For example, in some processing steps, the bias power may be higher than the plasma source power, but in some embodiments of the present technology, the bias power may be maintained lower than the plasma power, e.g., about 500 W or less, and may be about 400 W or less, about 300 W or less, about 200 W or less, about 100 W or less, or less.

[0038]

[0040] Applying a larger bias can increase the directionality of the delivery perpendicular to the plane across the substrate. Therefore, decreasing the delivered bias power reduces the amount of directionality, which can increase plasma effluent interaction within the feature. The plasma effluents can then etch the flowable film and remove it from the sidewalls of the trench in step 220. Simultaneously, or in addition, the more directionally delivered plasma effluents can penetrate the remaining film formed at the bottom of the feature and reduce hydrogen uptake to densify the film in optional step 225. As shown in FIG. 3B, material 315 may be removed from the sidewalls and overhang regions of substrate 305, thereby preserving the material deposited in the bottom region of the feature. This process may also reduce the hydrogen incorporation in the remaining material (e.g., hydrogen incorporation of about 40 atomic % or less), and may reduce the hydrogen incorporation to about 35 atomic % or less, about 30 atomic % or less, about 25 atomic % or less, about 20 atomic % or less, about 15 atomic % or less, about 10 atomic % or less, or about 5 atomic % or less hydrogen incorporation.

[0039]

[0041] Additional adjustments can be made to further increase etching of material deposited along the sidewalls of the feature by adjusting one or more characteristics of the supplied plasma power or bias power. For example, in some embodiments, both the plasma power source and the bias power source can be operated in a continuous wave mode. In addition, one or both of the power sources can be operated in a pulsed mode. In some embodiments, the source power can be operated in a continuous wave mode or a pulsed mode, while the bias power is operated in a pulsed mode. The pulse frequency of the bias power is about 100 Hz or greater, and can be about 200 Hz or greater, about 300 Hz or greater, about 500 Hz or greater, about 750 Hz or greater, about 1,000 Hz or greater, about 1,500 Hz or greater, about 2,000 Hz or greater, or greater. The bias power has a duty cycle of about 75% or less, and the bias power may be operated at a duty cycle of about 70% or less, about 60% or less, about 50% or less, about 40% or less, about 30% or less, about 20% or less, about 10% or less, about 5% or less, or less. By operating the bias power at a reduced duty cycle, such as an on-time duty of about 50% or less, a more isotropic etch may be performed within the feature, resulting in better material removal from the sidewalls, due to the larger amount of time per cycle.

[0040]

[0042] Additional power configurations may also include synchronization of the source power and bias power in a master / slave relationship. For example, both power sources may be operated in a pulse orientation, with the bias power synchronized to operate after the source power operates with each pulse. Inter-level pulsing may also be applied. For example, during the bias power on-duty, the source power may operate at a first plasma power. During the remainder of the cycle when the bias power is off, the source power may operate at a second plasma power greater than the first plasma power. This may increase isotropic etching by eliminating bias-induced directionality and may also increase the etching characteristics of the isotropic etch. In embodiments of the present technology, the deposition and etching process may be repeated any number of times within a cycle to fill the feature, filling the feature with amorphous silicon.

[0041]

[0043] Additionally, in some embodiments where silicon may be required to be converted within the feature, cycling may also include a conversion operation. By converting during each cycle, feature penetration issues may be completely resolved. Also, by performing a conversion step followed by curing and etching, deposited material is removed from the sidewalls before conversion, which may limit lateral film expansion within the trench or feature between the sidewalls, as previously described. Conversion may be performed in a different chamber from deposition and processing, although in some embodiments, two or more steps, including all steps, may be performed in a single processing chamber. This may reduce wait times compared to conventional processes.

[0042]

[0044] Method 200 may also optionally include converting the amorphous silicon to another material. For example, following etching and densification, one or more conversion precursors may be delivered to the processing region of the chamber. For example, a nitrogen-containing precursor, an oxygen-containing precursor, and / or a carbon-containing precursor may be delivered to the processing region of the chamber, along with any carrier or diluent gases. A plasma may be formed from the conversion precursor and then contact the amorphous silicon material in the feature. In optional step 230, plasma effluents of the conversion precursor may interact with the amorphous silicon material in the trench and convert the material to silicon nitride, silicon oxide, silicon carbide, silicon oxynitride, silicon oxycarbide, silicon carbonitride, or silicon oxycarbonitride, along with any other materials that may be used to convert an amorphous silicon film. The plasma power can be similar to the power discussed above, for example, from about 100 W up to about 1,000 W or more for capacitively coupled systems and up to 10 kW or more for inductively coupled plasma systems, although any type of conversion may also be implemented.

[0043]

[0045] Although the deposit can be formed to a few nanometers or more, by performing the etching process as described above, the thickness of the densified material can be controlled to a thickness of about 100 Å or less, and can be about 90 Å or less, about 80 Å or less, about 70 Å or less, about 60 Å or less, about 50 Å or less, about 40 Å or less, about 30 Å or less, about 20 Å or less, about 10 Å or less, or less. By controlling the thickness of the deposited material, conversion through the entire thickness can be more easily achieved, eliminating penetration issues common to conventional processes. As shown in FIG. 3C, material 315 remaining in the feature after the etching process can be completely converted to material 320 through the full depth of the film. This process can then be fully repeated to continue generating converted material down the feature.

[0044]

[0046] Regarding the deposition precursors used during any of the formation steps, any number of precursors can be used in the present technique. Silicon-containing precursors that can be used during any of the silicon oxide, silicon, or silicon nitride formation can include, but are not limited to, silane (SiH), disilane (SiH), or other organosilanes, including cyclohexasilane, silicon tetrafluoride (SiF), silicon tetrachloride (SiCl), dichlorosilane (SiHCl), tetraethyl orthosilicate (TEOS), and any other silicon-containing precursors that can be used to form silicon-containing films. In some embodiments, silicon-containing materials can be nitrogen-free, oxygen-free, and / or carbon-free. Oxygen-containing precursors used in any of the steps described throughout the present technique can include O, NO, NO, O, HO, and any other oxygen-containing precursors that can be used to form silicon oxide films or other films. Nitrogen-containing precursors used in any step can include N2, NO, NO2, NH3, N2H2, and any other nitrogen-containing precursor that can be used in forming silicon nitride films. Carbon-containing precursors can be or include any carbon-containing material, such as any hydrocarbon or any other precursor containing carbon. Any of the steps can include one or more additional precursors, such as Ar, He, Xe, Kr, or an inert precursor that can include other materials such as nitrogen, ammonia, hydrogen, or other precursors.

[0045]

[0047] Temperature and pressure can also affect the operation of the present technique. For example, in some embodiments, to facilitate film flow, the process is performed at a temperature of about 20°C or less, and may be performed at a temperature of about 0°C or less, about -20°C or less, about -50°C or less, about -75°C or less, about -100°C or less, or even lower. The temperature may be maintained within any of these ranges throughout the method, including during conversion as well as treatment and etching. The pressure within the chamber is kept relatively low, such as a chamber pressure of about 20 Torr or less, for any of the processes, and the pressure may be maintained at about 15 Torr or less, about 10 Torr or less, about 5 Torr or less, about 3 Torr or less, about 2 Torr or less, about 1 Torr or less, about 0.1 Torr or less, or even lower. By performing processes according to some embodiments of the present technique, improved filling of narrow features utilizing silicon-containing materials may be produced.

[0046]

[0048] In the foregoing description, for purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that particular embodiments may be practiced without some of these details, or with additional details.

[0047]

[0049] While several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative structures, and equivalents may be used without departing from the spirit of the embodiments. Additionally, some well-known processes and elements have not been described to avoid unnecessarily obscuring the present technology. Therefore, the above description should not be construed as limiting the scope of the present technology. Furthermore, while a method or process may be described sequentially or in steps, it should be understood that steps may be performed simultaneously or in a different order than listed.

[0048]

[0050] Where a range of values ​​is given, unless the context clearly indicates otherwise, each intervening value between the upper and lower limit of that range is specifically disclosed to the smallest unit of the lower limit. Any smaller ranges between any stated or unstated intervening value in a stated range, as well as any other stated or intervening value in that stated range, are also included. The upper and lower limits of such narrower ranges may individually be included or excluded from that range. Each range in which either or both limits are included in the narrower range, or neither limit is included in the narrower range, is also encompassed within the technology and covers any specifically excluded limit in the stated range. When a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0049]

[0051] As used in this specification and claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a precursor" includes a plurality of such precursors, reference to "the layer" includes a reference to one or more layers and equivalents known to those skilled in the art, and so forth.

[0050]

[0052] Additionally, the terms "comprise(s)", "comprising", "contain(s)", "containing", "include(s)", and "including", when used in this specification and claims, are intended to specify the presence of stated features, integers, components, or steps, but do not exclude the presence or addition of one or more other features, integers, components, steps, operations, or groups.

Claims

1. A processing method comprising: forming a plasma of a silicon-containing precursor; depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor, the semiconductor substrate contained within a processing region of a semiconductor processing chamber, the semiconductor substrate defining features therein, the processing region being defined at least in part between a faceplate and a substrate support upon which the semiconductor substrate rests; forming a plasma of a hydrogen-containing precursor in the processing region of the semiconductor processing chamber, the plasma of the hydrogen-containing precursor being formed at a first power level from a plasma power source and a bias power being applied to the substrate support from a bias power source at a second power level lower than the first power level; etching the flowable film from the sidewalls of the feature in the semiconductor substrate with plasma effluents of the hydrogen-containing precursor; densifying the remaining flowable film in the feature defined in the semiconductor substrate with plasma effluents of the hydrogen-containing precursor; A processing method comprising:

2. 10. The method of claim 1, wherein the feature in the semiconductor substrate is characterized by an aspect ratio of about 5:1 or greater, and the feature is characterized by a width across the feature of about 10 nm or less.

3. 10. The method of claim 1, wherein the bias power supply operates in a pulsed mode at a pulse frequency of about 1 kHz or less.

4. 4. The method of claim 3, wherein the plasma power supply operates in a continuous wave mode while the bias power supply operates in a pulsed mode.

5. 4. The method of claim 3, wherein the bias power supply operates at a duty cycle of about 75% or less.

6. The method of claim 1 , wherein the bias power supply is engaged subsequent to engagement of the plasma power supply.

7. 10. The method of claim 1, wherein said densifying comprises reducing the hydrogen content of said flowable film to about 30 atomic percent or less.

8. forming a plasma of the conversion precursor following said densifying; converting the flowable film into a modified film; The method of claim 1 further comprising:

9. 9. The method of claim 8, wherein the conversion precursor comprises a nitrogen-containing precursor, an oxygen-containing precursor, or a carbon-containing precursor.

10. The method of claim 8 , wherein the method is repeated in a predetermined cycle.

11. 9. The method of claim 8, wherein the temperature of the semiconductor substrate is maintained at a temperature of about 0[deg.] C. or less during the method.

12. A processing method comprising: forming a plasma of a silicon-containing precursor; depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor, the semiconductor substrate being contained within a processing region of a semiconductor processing chamber, the semiconductor substrate defining features within the semiconductor substrate; forming a plasma of a hydrogen-containing precursor in the processing region of the semiconductor processing chamber, the plasma of the hydrogen-containing precursor being formed at a first power level from a plasma power source and a bias power being applied to the plasma of the hydrogen-containing precursor from a bias power source at a second power level; etching the flowable film from sidewalls of the feature defined in the semiconductor substrate with plasma effluents of the hydrogen-containing precursor; densifying the remaining flowable film in the feature defined in the semiconductor substrate with plasma effluents of the hydrogen-containing precursor; A processing method comprising:

13. 13. The processing method of claim 12, wherein the plasma power supply providing the first power level operates continuously while the bias power supply operates in a pulsed mode at a frequency of about 1 kHz or less.

14. 14. The method of claim 13, wherein the bias power supply operates at a duty cycle of about 50% or less.

15. 13. The processing method of claim 12, wherein said etching completely removes said flowable film from said sidewalls of said feature above a base fill of said feature.

16. forming a plasma of the conversion precursor following said densifying; converting the flowable film into a modified film; The method of claim 12 further comprising:

17. 17. The method of claim 16, wherein the conversion precursor comprises a nitrogen-containing precursor, an oxygen-containing precursor, or a carbon-containing precursor.

18. 20. The process of claim 17, wherein the modified film comprises silicon nitride, silicon oxide, or silicon carbide.

19. forming a plasma of a silicon-containing precursor; depositing a flowable film on a semiconductor substrate using plasma effluents of the silicon-containing precursor, the semiconductor substrate being contained within a processing region of a semiconductor processing chamber, the semiconductor substrate defining features within the semiconductor substrate; forming a plasma of a hydrogen-containing precursor in the processing region of the semiconductor processing chamber; etching the flowable film from sidewalls of the feature defined in the semiconductor substrate with plasma effluents of the hydrogen-containing precursor; densifying the remaining flowable film in the feature defined in the semiconductor substrate with plasma effluents of the hydrogen-containing precursor; forming a plasma of the conversion precursor; converting the flowable film into a modified film; A processing method comprising:

20. 20. The process of claim 19, wherein the modified film comprises silicon and one or more of nitrogen, oxygen, or carbon.

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