Method and apparatus for improved metal ion filtration

Abstract

The present invention provides embodiments of methods and apparatus for improved ion filtration. In some embodiments, a substrate processing chamber includes: a chamber body and a chamber lid, the chamber lid being disposed on the chamber body to define a processing region within the chamber body below the lid; a collimator disposed in the processing region; a power source coupled to the collimator; and a first set of magnets disposed around the chamber body above the collimator, and a second set of magnets disposed around the chamber body below the collimator, the two sets of magnets together generating a guiding magnetic field, the guiding magnetic field being substantially perpendicular to the collimator.

Description

[0001] This application is a divisional application of the invention patent application with application number 201580027248.X filed on May 14, 2015 and invention name “Method and apparatus for improved metal ion filtration”. Technical Field

[0002] Embodiments of the present disclosure generally relate to substrate processing chambers for use in semiconductor manufacturing systems. Background Art

[0003] Reliably producing submicron and smaller features is a key technology for the next generation of very large scale integration (VLSI) and ultra large scale integration (ULSI) for semiconductor devices. However, with the imminent miniaturization of circuit technology, the reduced size of interconnect devices in VLSI and ULSI technology has placed additional demands on processing capabilities. Multi-level interconnects, which are at the core of VLSI and ULSI technology, require precise processing of high aspect ratio features such as vias and other interconnect devices.

[0004] As the circuit density of next generation devices increases, the width of interconnects such as vias, trenches, contacts, gate structures and other features and the width of dielectric materials between the interconnects are reduced to 45 nanometers and 32 nanometers or smaller. However, the dielectric thickness remains substantially constant, resulting in an increase in the aspect ratio of the depth to the width of the features.

[0005] Sputtering, also known as physical vapor deposition (PVD), is a method of forming metal features in integrated circuits. Sputtering deposits layers of material on a substrate. A source material, such as a target, is bombarded by ions that are strongly accelerated by an electric field to eject material from the target, which is then deposited on the substrate.

[0006] In the physical vapor deposition process, fast-moving ions hit the target material, thereby driving particles away from the target surface. Particles can be charged by interacting with incident ions via a charge transfer mechanism. Alternatively, particles can be charged by interacting with any electric field present in space, or particles can remain uncharged. Deposition generally occurs faster on the field area and near the top of the groove sidewall. During deposition, the ejected particles can travel in all directions, rather than in a direction generally perpendicular to the substrate surface, resulting in the formation of overhangs on the corners of the grooves. Overhangs placed on the opposite sides of the grooves or other openings can grow together, resulting in premature closure, and thus preventing the grooves or openings from being completely filled and forming holes or voids. When depositing conductive materials to form the conductive path of the device, such holes or voids adversely severely weaken the conductivity of the formed features. In addition, grooves and through holes with higher aspect ratios in next-generation devices are even more difficult to fill without generating voids.

[0007] Controlling the proportion of ions or ion density reaching the substrate surface within a certain range can improve the bottom and sidewall coverage during the metal layer deposition process. In one example, the particles driven away from the target material can be ionized and accelerated under the electrical bias applied to the substrate. The resulting narrow angle flux distribution encourages the particles to move downward into the groove before the early closure of the groove. It is believed that by increasing the proportion of ions / ion density near the substrate surface, the ion trajectory can be made more perpendicular to the substrate. When the accelerated ions approach the substrate surface, the momentum carried by the self-accelerating ions can reach deeper into the groove downward, where the ions are deflected toward the groove sidewalls under the influence of the electrical bias. Nevertheless, penetrating deeper into the groove reduces the overhang effect near the top of the sidewall. However, as the aspect ratio of the groove becomes higher and the substrate size becomes larger, it is more difficult to reach the bottom of the groove downward, and it is also more difficult to deposit materials uniformly across the substrate surface. Therefore, PVD processing remains a challenge to overcome the problem of overhang management.

[0008] Thus, the inventors have provided improved methods and apparatus for forming metal-containing layers with good management of the bottom and sidewalls. Summary of the invention

[0009] The present invention provides embodiments of methods and apparatus for improved ion filtration. In some embodiments, a substrate processing chamber includes: a chamber body and a chamber lid, the chamber lid being disposed on the chamber body to define a processing region within the chamber body below the lid; a collimator disposed in the processing region; a power supply coupled to the collimator; and a first set of magnets disposed around the chamber body above the collimator, and a second set of magnets disposed around the chamber body below the collimator, the two sets of magnets together generating a guiding magnetic field, the guiding magnetic field being substantially perpendicular to the collimator.

[0010] In some embodiments, a substrate processing chamber includes: a chamber body and a chamber lid, wherein the chamber lid is disposed on the chamber body and defines a processing region within the chamber body below the lid; a target material, wherein the target material is disposed below the chamber lid; a collimator, wherein the collimator is disposed in the processing region below the lid; a DC power supply, wherein the DC power supply is coupled to the collimator; and a first set of magnets, wherein the first set of magnets is disposed around the chamber body above the collimator, and a second set of magnets, wherein the second set of magnets is disposed around the chamber body below the collimator, wherein the two sets of magnets together generate a guiding magnetic field, wherein the guiding magnetic field is substantially perpendicular to the collimator.

[0011] In some embodiments, a method of depositing a metal layer on a substrate includes: supplying a gas mixture into a processing chamber; applying radio frequency or direct current power to form a plasma from the gas mixture to sputter a source material from a target disposed in the processing chamber; applying a direct current bias power to a collimator disposed in the processing chamber; generating a guide magnetic field substantially perpendicular to the collimator; and depositing the source material on the substrate.

[0012] Other and further embodiments of the disclosure are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The embodiments of the present disclosure, briefly summarized above and discussed in more detail below, can be understood by referring to the exemplary embodiments of the present disclosure depicted in the accompanying drawings. However, the accompanying drawings only illustrate typical embodiments of the present disclosure and are therefore not to be considered as limiting the scope of the present disclosure, as the present disclosure may allow other equally effective embodiments.

[0014] Figure 1 A schematic cross-sectional view of a processing chamber according to some embodiments of the present disclosure is depicted.

[0015] Figure 2 A top view of a collimator according to some embodiments of the present disclosure is shown.

[0016] Figure 3 Some embodiments of the present disclosure are shown in FIG. Figure 2 The voltage of the collimator in FIG. 1 is plotted as a function of time.

[0017] Figure 4 Magnetic fields generated in a processing chamber according to some embodiments of the present disclosure are depicted.

[0018] Figure 5 Magnetic fields generated in a processing chamber according to some embodiments of the present disclosure are depicted.

[0019] Figure 6A-6BDepicted is a cross-sectional view of a substrate during fabrication of a metal layer deposition process according to some embodiments of the present disclosure.

[0020] Figure 7 A flow chart of a method of depositing a metal layer on a substrate according to some embodiments of the present disclosure is shown.

[0021] For ease of understanding, the same reference numerals have been used as much as possible to designate the same elements common to the drawings. The drawings are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be advantageously integrated in other embodiments without repetition. DETAILED DESCRIPTION

[0022] The present invention provides embodiments of methods and apparatus for improved metal ion filtration. In some embodiments, the apparatus of the present invention can advantageously control the ion / neutral particle filtration effect so as to effectively control the ion trajectory behavior and assist in filling capacity from the bottom up during the physical vapor deposition process. For example, embodiments of the present disclosure can facilitate the deposition of materials in features formed on a substrate with excellent management of the bottom and sidewalls by utilizing enhanced metal ionization of ion filtration and improved control of flux angle distribution of ions and neutral particles before they reach the substrate level. As described in more detail below, metal ion filtration can be advantageously achieved by geometric collimation and electrical collimation. Although geometric collimation is effective for neutral particles and ions, electrical collimation is only effective for metal ions (with the help of DC bias and strong magnetic field arrangement). Higher metal ionization (due to less loss of collimator) and / or narrow ion angle expansion advantageously produce better deposition coverage. In some embodiments, bias collimator can also be used to control plasma potential.

[0023] Figure 1 A physical vapor deposition (PVD) chamber 100 (e.g., a sputtering processing chamber) is shown having a bipolar collimator (collimator 118) suitable for sputtering deposited materials according to some embodiments of the present disclosure. Examples of PVD chambers that may be adapted to benefit from the present disclosure include Plus and SIP PVD processing chambers, both of which are available from Applied Materials, Inc. in Santa Clara, Calif. Processing chambers available from other manufacturers may also be adapted to perform the embodiments described herein.

[0024] The PVD chamber 100 has an upper sidewall 102, a lower sidewall 103, and a lid portion 104 that define a body 105 that encloses an interior volume 106 of the PVD chamber 100. An adapter plate 107 may be disposed between the upper sidewall 102 and the lower sidewall 103. A substrate support, such as a substrate support 108, is disposed in the interior volume 106 of the PVD chamber 100. A substrate transfer port 109 is formed in the lower sidewall 103 for transferring substrates into and out of the interior volume 106.

[0025] In some embodiments, the PVD chamber 100 includes a sputtering chamber, also referred to as a physical vapor deposition (PVD) chamber, capable of depositing, for example, titanium, aluminum oxide, aluminum, aluminum oxynitride, copper, tantalum, tantalum nitride, tantalum oxynitride, titanium oxynitride, tungsten, or tungsten nitride on a substrate such as substrate 101.

[0026] A gas source 110 is coupled to the PVD chamber 100 to supply process gases into the interior volume 106. In some embodiments, the process gases may include an inert gas, a non-reactive gas, and a reactive gas (if desired). Examples of process gases that may be provided by the gas source 110 include, but are not limited to, argon (Ar), helium (He), neon (Ne), nitrogen (N2), oxygen (O2), and water vapor H2O, among other process gases.

[0027] The pumping device 112 is coupled to the PVD chamber 100 to communicate with the internal volume 106 to control the pressure of the internal volume 106. In some embodiments, the pressure level of the PVD chamber 100 can be maintained at about 1 Torr or less. In another embodiment, the pressure level of the PVD chamber 100 can be maintained at about 500 mTorr or less. In yet another embodiment, the pressure level of the PVD chamber 100 can be maintained at about 1 mTorr and about 300 mTorr.

[0028] The cover portion 104 may support a sputtering source 114, such as a target. In some embodiments, the sputtering source 114 may be made of a material including, or in some embodiments, may be made of a material consisting essentially of, titanium (Ti), tantalum (Ta), tungsten (W), cobalt (Co), nickel (Ni), copper (Cu), aluminum (Al), alloys of the above metals, combinations of the above metals, or the like. For example, in some embodiments, the sputtering source 114 may be made of one or more materials selected from the group consisting of the following materials: aluminum (Al), cobalt (Co), chromium (Cr), nickel (Ni), tantalum (Ta), titanium (Ti), tungsten (W), alloys of the above metals, combinations of the above metals, and the like. In some embodiments, the sputtering source 114 may be made of titanium (Ti), tantalum (Ta), or aluminum (Al).

[0029] The sputtering source 114 can be coupled to a source assembly 116, which includes a power supply 117 (e.g., a power supply) for the sputtering source 114. The power supply 117 can provide RF source power or DC source power. In some embodiments, both RF and DC source power are provided. A magnetron assembly 119 including a magnet group can be coupled adjacent to the sputtering source 114, the magnetron assembly enhancing efficient sputtering of material from the sputtering source 114 during processing. Examples of magnetron assemblies include electromagnetic linear magnetrons, serpentine magnetrons, spiral magnetrons, double-toed magnetrons, rectangularized spiral magnetrons, and the like.

[0030] In some embodiments, a first set of magnets 194 can be disposed about the chamber body above the collimator, such as between the adapter plate 107 and the upper sidewall 102 to assist in generating an electron field for metal ions driven away from the sputtering source 114. Additionally, a second set of magnets 196 can be disposed about the chamber body below the collimator, such as adjacent the cover portion 104 to assist in generating an electric field to drive material away from the sputtering source 114. The number, size, and strength of the magnets disposed about the PVD chamber 100 can be selected to improve plasma dissociation and sputtering efficiency. For example, in some embodiments, the first set of magnets 194 can have a total strength of about 500 to about 3000 gauss at the target surface. In some embodiments, the second set of magnets 196 can have a total strength of about 0 to about 300 gauss, measured about 7 inches from (e.g., below) the target surface. In some embodiments, the guiding magnetic field generated by the first set of magnets 194 and the second set of magnets 196 may have a total strength of about 10 to about 300 gauss, measured at about 7 inches from (e.g., below) the target surface. The individual magnets of the first set of magnets 194 may be permanent magnets, electromagnets (e.g., electromagnetic coils), or a combination of the above. The individual magnets of the second set of magnets 196 may be permanent magnets, electromagnets (e.g., electromagnetic coils), or a combination of the above. The overall magnetic field strength of the guiding magnetic field and the imbalance ratio of the magnetron assembly (e.g., total surface area of ​​the outer poles / total surface area of ​​the inner poles) can be optimized to produce a desired plasma density and enhance plasma diffusion. For example, generally, increasing the imbalance ratio (e.g., to about 2-5 or more) increases the plasma power density, thereby enhancing the generation of metal ion flux.

[0031] In some embodiments, an additional RF power source 180 may also be coupled to the PVD chamber 100 via the substrate support 108 to provide bias power between the sputtering source 114 and the substrate support 108. In some embodiments, the RF power source 180 may have a frequency between about 400 Hz and about 60 MHz, such as about 13.56 MHz.

[0032] The collimator 118 can be positioned between the sputtering source 114 and the substrate support 108 in the interior volume 106. The collimator 118 can be in a bipolar mode to control the direction of ions passing through the collimator 118. A controllable direct current (DC) or alternating current collimator power supply 190 can be coupled to the collimator 118 to provide an alternating pulsed positive or negative voltage to the collimator 118 to control the collimator 118 in a bipolar mode (e.g., a bipolar power supply). Details regarding the bipolar collimator 118 will be described below with reference to Figure 2-3 Further Discussion. In some embodiments, the collimator power supply 190 is a DC power supply. In some embodiments, the collimator power supply 190 is a bipolar pulsed DC power supply.

[0033] The shielding tube 120 may be adjacent to the collimator 118 and the interior of the cover portion 104. The collimator 118 includes a plurality of holes to direct a gas and / or material flux within the interior volume 106. The collimator 118 may be mechanically coupled and electrically coupled to the shielding tube 120. In some embodiments, the collimator 118 is mechanically coupled to the shielding tube 120 by a process such as welding, such that the collimator 118 is integral with the shielding tube 120. In other embodiments, the collimator 118 may be electrically floating within the PVD chamber 100. In another embodiment, the collimator 118 may be coupled to a power source and / or electrically coupled to the cover portion 104 of the body 105 of the PVD chamber 100.

[0034] The shielding tube 120 may include a tubular body 121 having a groove 122 formed in an upper surface of the tubular body 121. The groove 122 provides an interface with a lower surface of the collimator 118. The tubular body 121 of the shielding tube 120 may include a shoulder region 123 having an inner diameter that is smaller than the inner diameter of the remainder of the tubular body 121. In some embodiments, the inner surface of the tubular body 121 transitions radially inwardly along a tapered surface 124 to the inner surface of the shoulder region 123. A shielding ring 126 may be disposed in the PVD chamber 100 adjacent to the shielding tube 120 and intermediate the shielding tube 120 and the adapter plate 107. The shielding ring 126 may be at least partially disposed in a groove 128 formed by opposing sides of the shoulder region 123 of the shielding tube 120 and an inner sidewall of the adapter plate 107.

[0035] In one aspect, the shield ring 126 includes an axially protruding annular sidewall 127 that includes an inner diameter that is greater than the outer diameter of the shoulder region 123 of the shield tube 120. A radial flange 130 extends from the annular sidewall 127. The radial flange 130 may be formed at an angle relative to the inner diameter surface of the annular sidewall 127 of the shield ring 126 that is greater than about ninety degrees (90°). The radial flange 130 includes a protrusion 132 formed on a lower surface of the radial flange 130. The protrusion 132 may be an annular ridge extending from the surface of the radial flange 130 in an orientation that is substantially parallel to the inner diameter surface of the annular sidewall 127 of the shield ring 126. The protrusion 132 is generally adapted to mate with a recessed flange 134 formed in an edge ring 136 that is disposed on the substrate support 108. The recessed flange 134 may be an annular groove formed in the edge ring 136. The engagement of the protrusions 132 with the recessed ledges 134 centers the shield ring 126 relative to the longitudinal axis of the substrate support 108. The substrate 101 (shown supported on lift pins 140) is centered relative to the longitudinal axis of the substrate support 108 by performing a coordinate positioning calibration between the substrate support 108 and a robot blade (not shown). Thus, the substrate 101 can be centered within the PVD chamber 100 and the shield ring 126 can be radially centered about the substrate 101 during processing.

[0036] In operation, a robot blade (not shown) carrying a substrate 101 extends through the substrate transfer port 109. The substrate support 108 may be lowered to allow the substrate 101 to be transferred to the lift pins 140 extending from the substrate support 108. The lifting and lowering of the substrate support 108 and / or the lift pins 140 may be controlled by a driver 142 coupled to the substrate support 108. The substrate 101 may be lowered onto a substrate receiving surface 144 of the substrate support 108. With the substrate 101 positioned on the substrate receiving surface 144 of the substrate support 108, sputter deposition may be performed on the substrate 101. During processing, the edge ring 136 may be electrically insulated from the substrate 101. Thus, the substrate receiving surface 144 may include a height that is greater than the height of a portion of the edge ring 136 adjacent to the substrate 101 so as to prevent the substrate 101 from contacting the edge ring 136. During sputter deposition, the temperature of the substrate 101 may be controlled using a thermal control channel 146 disposed in the substrate support 108.

[0037] After sputter deposition, the substrate 101 can be raised to a position spaced from the substrate support 108 by utilizing the lift pins 140. The raised position can be proximate to one or both of the shield ring 126 and the reflector ring 148 adjacent to the adapter plate 107. The adapter plate 107 includes one or more lamps 150 coupled to the adapter plate 107, the lamps being located intermediate the lower surface of the reflector ring 148 and the concave surface 152 of the adapter plate 107. The lamps 150 provide optical energy and / or radiant energy having visible or near visible wavelengths, such as wavelengths in the infrared (IR) and / or ultraviolet (UV) spectrum. The energy from the lamps 150 is focused radially inward toward the back side (i.e., the lower surface) of the substrate 101 to heat the substrate 101 and the material deposited on the substrate 101. Reflective surfaces on chamber components surrounding the substrate 101 serve to focus energy toward the back side of the substrate 101 and away from other chamber components where it would be lost and / or unused. During heating, the adapter plate 107 may be coupled to a coolant source 154 to control the temperature of the adapter plate 207.

[0038] After the substrate 101 is controlled to a predetermined temperature, the substrate 101 is lowered into position on the substrate receiving surface 144 of the substrate support 108. The substrate 101 may be rapidly cooled by conduction using the thermal control channels 146 in the substrate support 108. The temperature of the substrate 101 may be ramped down from the first temperature to the second temperature over a period of seconds to about 1 minute. The substrate 101 may be removed from the PVD chamber 100 via the substrate transfer port 109 for further processing. The substrate 101 may be maintained in a predetermined temperature range, such as less than about 250°C.

[0039] A controller 198 is coupled to the PVD chamber 100. The controller 198 includes a central processing unit (CPU) 160, a memory 158, and support circuits 162. The controller 198 is used to control the process sequence, thereby regulating the gas flow from the gas source 110 into the PVD chamber 100 and controlling the ion bombardment of the sputtering source 114. The CPU 160 may have any form of general purpose computer processor that can be used in an industrial environment. The software program may be stored in the memory 158, such as a random access memory, a read-only memory, a floppy disk or hard disk drive, or other form of digital storage. The support circuits 162 are coupled to the CPU 160 in a conventional manner and may include cache memory, clock circuits, input / output subsystems, power supplies, and the like. The software program, when executed by the CPU 160, transforms the CPU into a special purpose computer (controller) 198, which controls the PVD chamber 100 to perform processes in accordance with the present disclosure. The software program may also be stored and / or executed by a second controller (not shown) located remotely from the PVD chamber 100 .

[0040] During processing, material is sputtered from the sputtering source 114 and deposited on the surface of the substrate 101. The sputtering source 114 and the substrate support 108 are biased relative to each other by the power supply 117 or the RF power supply 180 to maintain a plasma formed using the process gas supplied by the gas source 110. The DC pulse bias power applied to the collimator 118 also helps control the ratio of ions to neutral particles passing through the collimator 118, thereby enhancing the filling capacity of the trench sidewalls and bottom. The ions from the plasma are accelerated toward the sputtering source 114 and strike the sputtering source 114, causing the target material to be driven away from the sputtering source 114. The driven target material and the process gas form a layer of a predetermined composition on the substrate 101.

[0041] Figure 2 A top view of the collimator 118 is shown coupled to a collimator power supply 190, which may be located at Figure 1 The collimator 118 is a generally honeycomb structure having hexagonal walls 226 that separate hexagonal holes 244 in a close-packed arrangement. Additional walls 242 may be provided to connect the honeycomb structure to the generally cylindrical body 206 of the collimator 118. The aspect ratio of the hexagonal holes 244 may be defined as the depth of the holes 244 (equal to the collimator length) divided by the width 246 of the holes 244. In some embodiments, the thickness of the wall 226 is between about 0.06 inches and about 0.18 inches. In some embodiments, the thickness of the wall 226 is between about 0.12 inches and about 0.15 inches. In some embodiments, the collimator 118 comprises a material selected from aluminum, copper, and stainless steel.

[0042] The honeycomb structure of the collimator 118 can be used as an integrated flux optimizer 210 to optimize the flow path, ion fraction, and ion trajectory behavior of ions as they pass through the collimator 118. In some embodiments, the hexagonal wall 226 adjacent to the shield portion 892 has a chamfer 250 and a radius. The shield portion 892 of the collimator 118 can assist in mounting the collimator 118 into the PVD chamber 100.

[0043] In some embodiments, the collimator 118 may be machined from a single piece of aluminum. The collimator 118 may be coated or anodized as appropriate. Alternatively, the collimator 118 may be made of other materials compatible with the processing environment and may also include one or more sections. Alternatively, the shield portion 892 and the integrated flux optimizer 210 are formed as separate pieces and coupled together using a suitable attachment means such as welding.

[0044] The collimator 118 acts as a filter to capture ions and neutral particles emitted from the material from the sputtering source 114 at angles exceeding a selected angle (approximately perpendicular to the substrate 101). The collimator 118 can have an aspect ratio variation across the width of the collimator 118 to allow, for example, different percentages of ions emitted from the center or peripheral regions of the material from the sputtering source 114 to pass through the collimator 118. Thus, the number of ions deposited on the peripheral and central regions of the substrate 101 and the angle of arrival of the ions are adjusted and controlled. As a result, the material can be more uniformly sputtered and deposited across the surface of the substrate 101. In addition, the material can also be more uniformly deposited on the bottom and sidewalls of features with a high aspect ratio, especially through holes and trenches with a high aspect ratio located near the periphery of the substrate 101.

[0045] In some embodiments, a collimator power supply 190 coupled to the collimator 118 can supply voltage power to the collimator 118 in a pulsed or alternating manner to assist in localized deposition on the substrate 101. The collimator power supply 190 is configured to provide negative and / or positive voltage pulses to the collimator 118 so as to control the collimator 118 in a unipolar or bipolar mode. In some embodiments, the collimator 118 controlled in a bipolar mode can control and trap ions so as to produce different ratios of ions and neutral particles passing through the collimator 118. Without wishing to be bound by theory, for the absence of a strong guiding magnetic field, the inventors believe that a positive voltage pulse applied to the collimator 118 can attract electrons in the plasma toward the substrate surface, while a negative voltage pulse applied to the collimator 118 can push electrons in the plasma toward the target. Therefore, by applying a pulsed alternating positive and negative voltage to the collimator 118, the orientation of ions and neutral particles passing through the collimator 118 can be more effectively controlled.

[0046] Figure 3 3 shows a voltage signal 302 detected by the collimator 118 when DC power is applied to the collimator 118. The voltage supplied to the collimator 118 from the collimator power supply 190 may be controlled in a pulse mode, such as Figure 3, to apply alternating positive voltage 310 and negative voltage 312 pulses to the collimator 118. The positive voltage pulses 310 and negative voltage pulses 312 may have predetermined pulse widths 304, 308 (e.g., pulse times) and pulse amplitudes 306, 314 (e.g., pulse voltage values), respectively. The pulse modulation (e.g., pulse width and pulse amplitude) is controlled to achieve a predetermined deposition profile. For example, in embodiments where more directional ions are accelerated toward the substrate surface to enhance bottom-up filling capabilities, a longer pulse width (e.g., longer pulse time) may be supplied to the positive voltage to assist deposition on the bottom of the trench. In contrast, in embodiments where non-directional ions are deposited on the sidewalls of the trench or to sputter-etch deposits at the corners of the trench, a longer pulse width (e.g., longer pulse time) may be supplied to the negative voltage to enhance sidewall deposition management. The voltage supplied to the collimator 118 may also be in a continuous mode.

[0047] In some embodiments, the DC bias power pulses from the collimator power supply 190 may have a duty cycle between about 5% (e.g., 5% on and 95% off) and about 70% (e.g., 70% on and 30% off) at a bias frequency between about 400 Hz and about 60 MHz, such as between about 5% and about 50%, such as between about 15% and about 45%. Alternatively, the cycle of the DC bias power pulsed to the collimator 118 may be controlled by a predetermined number of time periods performed. For example, the DC bias power may be pulsed at a frequency of from about every 1 millisecond to about every 100 milliseconds. In some embodiments, the DC bias power may be controlled between about 1 kW and about 10 kW.

[0048] Figure 4 The directions of travel produced by ions passing through the collimator 118 are shown. Figure 4 As can be seen in FIG. 1 , the traveling direction of the ions is not completely perpendicular to the substrate 101. To further correct the traveling direction and thereby improve deposition on the bottom of the trench, the second set of magnets 196 generates a guiding magnetic field that is substantially perpendicular to the collimator 118. The strong guiding magnetic field provides confinement of the electrons, and thus the traveling direction of the ions passing through the collimator 118 becomes more perpendicular to the substrate 101, as shown in FIG. Figure 5 As shown, this advantageously reduces metal ion loss from the walls of the collimator 118 .

[0049] In some embodiments, the material from the sputtering source 114 used in the PVD chamber 100 illustrated in the present invention is a metal (such as a copper alloy) configured to deposit a metal layer (such as a copper layer) into the opening 602 formed in the insulating material 604 disposed on the substrate 101, such as Fig. 6AAs shown. During deposition, a gas mixture is supplied to the PVD chamber 100 to form a metal layer 606 (such as a copper layer) in an opening 602 formed on the substrate 101 using a sputtering material having a high filling capacity from the bottom up. In some embodiments, the gas mixture may include reactive gases, non-reactive gases, inert gases, and the like. Examples of reactive and non-reactive gases include, but are not limited to, O2, N2, N2O, NO2, NH3, and H2O, and the like. Examples of inert gases include, but are not limited to, argon (Ar), neon (Ne), helium (He), xenon (Xe), and krypton (Kr), and the like. In a specific embodiment illustrated in the present invention, the gas mixture supplied to the processing chamber includes at least one nitrogen-containing gas and / or an inert gas. A metal alloy target made of a copper-containing alloy can be used as a source material of a sputtering source 114 for a sputtering process. The copper (Cu)-containing target as described in the present invention is for illustrative purposes only and should not be considered to limit the scope of the present disclosure. In addition, the metal or metal alloy target that can be used as the sputtering source 114 can be made of a material from the group consisting of the following materials: aluminum (Al), cobalt (Co), chromium (Cr), nickel (Ni), tantalum (Ta), titanium (Ti), tungsten (W), alloys of the above metals, combinations of the above metals, and the like.

[0050] After the gas mixture is supplied into the PVD chamber 100 for processing, high voltage power is supplied to the sputtering source 114 (eg, a Cu target) to sputter a metallic Cu source material, such as Cu, in the form of copper ions from the sputtering source 114. 2+ . A bias power applied between the sputtering source 114 and the substrate support 108 maintains a plasma formed from the gas mixture in the PVD chamber 100. The DC bias pulse power supplied to the collimator 118 can help control the ion fraction, ion ratio, and ion trajectory path extending toward the substrate surface. Ions primarily from the gas mixture bombard the material in the sputtering source 114 and sputter the material out of the sputtering source 114. The gas mixture and / or other process parameters can be varied during the sputtering deposition process, thereby producing a gradient of the deposited metal layer 606, the film properties of which are controlled for different film quality requirements.

[0051] In some embodiments, an RF source power between about 500 watts and about 25 kilowatts may be supplied at a frequency between about 400 kHz and about 60 MHz. An RF bias power of up to about 3000 watts may be supplied to the substrate support at a frequency of 13.56 MHz or 2 MHz. In some embodiments, an RF source power between about 100 watts and about 3000 watts may be supplied to the gas mixture at a frequency between about 400 kHz and about 60 MHz. In some cases, dual or triple frequencies may be used to modulate the ion energy. A DC bias power between about 1 kilowatt and about 10 kilowatts may be applied to the collimator in a pulsed mode. Alternatively, a DC bias power may be applied to the collimator in a continuous mode.

[0052] While supplying the gas mixture and the pulsed RF bias power pattern to perform the deposition process, a plurality of process parameters may also be controlled. The pressure of the processing chamber may be controlled between about 0.5 mTorr and about 500 mTorr, such as between about 1 mTorr and about 100 mTorr, for example about 20 mTorr. The substrate temperature may be controlled between about -40°C and about 450°C.

[0053] After the deposition process, a metal layer 606, such as a copper layer, may be conformally deposited in the opening 602 with good management of the sidewall and bottom deposition, such as Figure 6B The deposition process may be performed until the opening 602 defined in the insulating material 604 layer has been completely filled with a metal layer 606 , which is illustrated by phantom line 608 .

[0054] Figure 7 A flow chart of a method 700 for depositing material on a substrate according to some embodiments of the present disclosure is depicted. In step 705, a gas mixture is supplied to a processing chamber. In step 710, RF source power is applied to the gas mixture to form a plasma to sputter source material from a target disposed in the processing chamber. In step 715, to control the direction of travel of metal ions emitted from the source, a DC bias power is applied to a collimator disposed in the processing chamber. In step 720, a steering magnetic field substantially perpendicular to the collimator is generated to further control the direction of travel of the metal ions. In step 725, the sputtered source material is deposited on the substrate.

[0055] Thus, the present invention has provided an apparatus for placing a bipolar collimator in a physical vapor deposition chamber and a method for using the apparatus. By utilizing a bipolar collimator and a guide magnetic field in a physical vapor deposition chamber, effective control of the ion / neutral particle filtering effect can be obtained to effectively control ion trajectory behavior and assist bottom-up filling capability during a physical vapor deposition process.

[0056] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. A substrate processing chamber, comprising: a chamber body and a chamber lid disposed on the chamber body, the chamber lid defining a processing area within the chamber body and below the chamber lid; a substrate support disposed within the chamber body and opposite the chamber lid; a collimator disposed in the processing region between the chamber lid and the substrate support; a power source coupled to the collimator; a first set of magnets disposed about the chamber body above the collimator and configured to assist in generating an electric field to drive material away from the target when the target is mounted under the chamber lid; and a second set of magnets disposed about the chamber body below the collimator and configured to assist in generating an electric field to guide metal ions driven from the target, wherein the first set of magnets and the second set of magnets together generate a steering magnetic field that guides ions to travel through the collimator in a direction perpendicular to the substrate during processing. 2 . The substrate processing chamber of claim 1 , wherein the power source is one or more of a direct current power source and a radio frequency power source.

3. The substrate processing chamber of claim 1, wherein the power supply is a bipolar power supply.

4. The substrate processing chamber of claim 1, wherein the power supply is a bipolar pulsed DC power supply.

5. The substrate processing chamber of claim 1, wherein the collimator is configured in a bipolar mode.

6. The substrate processing chamber of any one of claims 1-5, further comprising the target material installed under the chamber cover, wherein the target material is made of aluminum, titanium, tantalum, tungsten, chromium, nickel, copper, cobalt, alloys of the above metals, or combinations of the above metals.

7. The substrate processing chamber of any one of claims 1 to 5, further comprising: A magnetron assembly is disposed above the chamber cover.

8. The substrate processing chamber of any one of claims 1 to 5, further comprising: A radio frequency bias power is coupled to the substrate support.

9. The substrate processing chamber of any one of claims 1-5, wherein the second set of magnets comprises a plurality of electromagnetic coils.

10. A method for depositing a material on a substrate, the method comprising the steps of: supplying a gas mixture into a processing chamber; applying radio frequency or direct current power to form a plasma from the gas mixture to sputter source material from a target disposed in the processing chamber; applying a DC bias power to a collimator disposed in the processing chamber; generating a guiding magnetic field to guide metal ions through the collimator, wherein the guiding magnetic field is generated by using a first set of magnets disposed above the collimator around the processing chamber and configured to assist in generating an electric field to drive material away from the target, and a second set of magnets disposed below the collimator around the processing chamber to assist in generating an electric field to guide the metal ions driven away from the target, such that the first set of magnets and the second set of magnets together generate the guiding magnetic field; and The source material is deposited onto the substrate.

11. The method of claim 10, wherein the step of applying the DC bias power to the collimator further comprises the following steps: Positive and negative voltages are alternately applied to the collimator pulses.

12. The method of claim 10, wherein at least one of the first set of magnets or the second set of magnets comprises a plurality of electromagnetic coils.

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