WO2010019264A2

WO2010019264A2 - Chemical mechanical polisher having movable slurry dispensers and method

Info

Publication number: WO2010019264A2
Application number: PCT/US2009/004667
Authority: WO
Inventors: Yulin Wang; Alpay Yilmaz
Original assignee: Applied Materials, Inc.
Priority date: 2008-08-14
Filing date: 2009-08-14
Publication date: 2010-02-18
Also published as: JP2011530422A; CN102124545A; JP5542818B2; WO2010019264A3; KR20110065464A; CN102124545B

Abstract

A chemical mechanical polisher comprises a polishing platen capable of supporting a polishing pad, first and second substrate carriers that are each capable of holding a substrate against the polishing pad and first and second movable slurry dispansers. The movable slurry dispenser comprises (i) an arm comprising a pivoting end and a distal end, (ii) at least one slurry dispensing nozzle on the distal end, and (iii) a dispenser drive capable of rotating the arm about the pivoting end to swing the slurry dispensing nozzle at the distal end to dispense slurry across the polishing platen. In another version, the movable slurry dispenser comprises a hinged arm having a plurality of sections that are joined at one or more hinge joints, a pivoting end and a distal end, and at least one slurry dispensing nozzle located at or near the distal end.

Description

CHEMICAL MECHANICAL POLISHER

HAVING MOVABLE SLURRY DISPENSERS AND METHOD

BACKGROUND

Embodiments of the present invention relate to a chemical mechanical polisher having movable slurry dispensers and related methods. In the fabrication of the integrated circuits (ICs) and displays, chemical-mechanical planarization (CMP) is used to smoothen the surface topography of a substrate for subsequent etching and deposition processes. A typical CMP polisher comprises a polishing head that oscillates and presses a substrate against a polishing pad while a slurry of abrasive particles is supplied to the polishing pad to polish the substrate. CMP can be used to planarize dielectric layers, deep or shallow trenches filled with polysilicon or silicon oxide, and metal films. It is believed that CMP polishing is a result of both chemical and mechanical effects, for example, a chemically altered layer is repeatedly formed at the surface of the material being polished and then polished away. For example, in metal polishing, a metal oxide layer can be formed and removed repeatedly from the surface of the metal layer during CMP polishing. In oxide polishing, the oxide layer is both chemically and physically eroded by the polishing slurry.

One type of conventional slurry dispenser comprises a fixed arm having a single slurry dispensing nozzle which releases slurry from a fixed point above the polishing pad. The slurry spreads across the polishing pad from the rotary or oscillating motion of the polishing pad and/or substrate carrier. However, because the slurry is dispensed from a single position above the platen, which is often at a mid-point of the radius of the platen, the resultant distribution of slurry across the surface of the platen is not always very uniform. Rotation of the underlying polishing platen and the resultant centrifugal forces causes the slurry to spread radially outward from the median point. However, a preferentially higher concentration of slurry forms in a circular strip that radiates outward from the median dispensing point due to these centrifugal forces, and a lower slurry concentration region forms between the point of dispensation and the radially inner region. This can result in uneven polishing rates across the diameter of the substrate being polished.

Multipoint slurry dispensers have also been developed to provide a more uniform distribution of slurry for polishing single substrates, as for example, described in US patent number 6,284,092, entitled "CMP Slurry Atomization Slurry Dispense System". A sweeping multipoint slurry dispenser has also been used to spread the slurry across the pad, as for example, described in US patent number 7,052,374, entitled "Multipurpose Slurry Delivery Arm for Chemical Mechanical Polishing". However, while these slurry dispensing systems provide a better slurry distribution for single substrate polishers, they do not provide effective slurry distribution for newer generations of CMP polishers which use multiple carrier heads to polish several substrates at the same time or which are used for polishing large substrates. Thus it is desirable to have a chemical mechanical polisher with a slurry dispensing system that provides a more uniform distribution of slurry across the surface of the polishing pad for simultaneously polishing multiple substrates or for polishing large substrates.

SUMMARY

A chemical mechanical polisher comprises a polishing platen capable of supporting a polishing pad, first and second substrate carriers that are each capable of holding a substrate against the polishing pad, and first and second slurry dispensers. First and second slurry dispensers each comprise (i) an arm comprising a pivoting end and a distal end, (ii) at least one slurry dispensing nozzle on the distal end, and (iii) a dispenser drive capable of rotating the arm about the pivoting end to swing the slurry dispensing nozzle at the distal end to dispense slurry across the polishing platen.

A chemical mechanical polishing method comprises rubbing first and second substrates against a polishing pad, and dispensing polishing slurry before each of the first and second substrates.

A chemical mechanical polisher for polishing a substrate with a slurry, comprises a polishing platen for supporting a polishing pad, a substrate carrier capable of holding a substrate against the polishing platen, and a slurry dispenser comprising a hinged arm having a plurality of sections that are joined at one or more hinge joints, a pivoting end and a distal end, and at least one slurry dispensing nozzle located at or near the distal end.

A chemical mechanical polishing method comprising rubbing a substrate against a polishing pad mounted on a polishing platen; providing a hinged slurry dispenser arm comprising a first section and a second section that are joined to one another at hinge joints, a pivoting end, a distal end, and at least one slurry dispensing nozzle located at or near the distal end; and moving the first section relative to the second section to dispense polishing slurry in a distribution pattern across the polishing pad.

DRAWINGS

These features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, which illustrate examples of the invention. However, it is to be understood that each of the features can be used in the invention in general, not merely in the context of the particular drawings, and the invention includes any combination of these features, where: FIG. 1 is a perspective view of a polishing platen assembly comprising a polishing platen, moveable slurry dispenser, and polishing pad conditioner, in the standby position;

FIG. 2 is a perspective view of the polishing platen assembly of FIG. 1 showing the movable slurry dispenser dispensing polishing slurry onto the polishing pad; FIG. 3 is a cross sectional side view of an embodiment of a slurry dispenser arm of FIG. 2;

FIG. 4A is a perspective view of an embodiment of a chemical mechanical polisher;

FIG. 4B is a partially exploded perspective view of the polisher of FIG. 4A; FIG. 4C is a diagrammatic top view of the tabletop of the polisher of FIG. 4A;

FIG. 5A is a top view of a polishing platen assembly showing another embodiment of a movable slurry dispenser;

FIG. 5B and FIG. 5C are sectional side and sectional top views of the movable slurry dispenser of FIG. 5A; FIG. 6A is a perspective view of an another embodiment of a slurry dispenser mounted on a tabletop of a polishing station of a chemical mechanical polisher;

FIG. 6B is a cross-sectional view of the slurry dispenser of FIG. 6A showing a tubular section having feed tubes running therethrough; and

FIG. 7 is a perspective view of the slurry dispenser of FIG. 6A that shows two different arm positions.

DESCRIPTION

A chemical mechanical polisher 100 is useful for polishing a surface of a substrate. For example, the polisher 100 can be used to polish a surface of a substrate that comprises copper interconnect lines or vias. In another application, the polisher can be used to polish a surface of a silicon dioxide layer on a substrate. Many other polishing applications and uses, as would be apparent to those of ordinary skill in the art, are also within the scope of the present invention. An embodiment of a polisher 100 suitable for polishing a surface of a substrate comprising a semiconductor wafer, display, or panel, is shown in FIG. 1. The polisher 100 comprises a tabletop 106 that holds one or more polishing stations 108 that can operate simultaneously and independently. Each polishing station 108 comprises a polishing platen 110 that supports a polishing pad 112. First and second substrate carriers 120a, b each press a substrate 140a,b, respectively, against the polishing pad 112 while the platen 110 rotates, oscillates or vibrates. In one version, the platen 110 is rotated by a platen motor 117 which is coupled to the underside of the platen 110 with a drive shaft. In one version, the platen motor 117 is a variable speed direct current motor, such as a servo-motor, which can selectively provide variable substrate rotation speeds during polishing. The platen 110 can be an aluminum or stainless steel plate.

The polishing pad 112 mounted on the platen 110 typically comprises a planar disc having a radius that is sized sufficiently large to provide coverage for at least two substrates 140a, b. The polishing pad 112 contacts and rotates against the substrates 140a, b (which can also be rotated, oscillated or vibrated themselves) to polish each substrate 140a,b. The polishing pad 112 comprises a polishing surface 113 made of a material that is sufficiently abrasive to polish and remove undesired material from the substrates 140a,b without excessively scratching or otherwise damaging the substrate surface. For example, the polishing surface 113 may be made of a polymer, felt, paper, cloth, ceramic, or other such materials. The polishing surface 113 can also include more grooves (not shown) to enhance the flow of the polishing slurry over the polishing surface 113. For example, a suitable polishing pad 112 comprises a fixed abrasive polishing pad, manufactured by 3M Superabrasives and Microfinishing Systems Division, St. Paul, Minnesota, which contains abrasive particles, such as silica, embedded in a resin. In one version, the polishing pad 112 is adhered to the platen 110, which is about the same diameter as the polishing pad 112, using a pressure sensitive adhesive.

First and second substrate carriers 120a,b are each adapted to hold a substrate 140a, b, respectively, against the polishing pad 112. The substrates 140a,b are held onto each substrate carrier 120a,b with a vacuum or surface tension. Each of the substrate carriers 120a,b apply a pressure while independently rotating and oscillating back-and-forth across the polishing pad 112 to achieve a uniformly polished surface on the substrates 140a, b. During polishing, a pneumatic system (not shown) lowers the substrate carriers 120a,b onto the polishing pad 112 to press the substrates 140a,b against the polishing pad 112 with a predetermined loading force. The platen motor 117 rotates the platen 110 and polishing pad 112. At the same time, each substrate carrier 120a,b rotates a substrate 140a,b, while sliders (not shown) linearly drive the substrate carriers 120a,b back and forth to oscillate the substrates 140a,b laterally on the surface of the polishing pad 112. The substrate carriers 120a,b are driven by one or more carrier motors (not shown), which can also be a variable speed direct current motor, such as a servo-motor, that can provide variable substrate rotational speeds and can also move the substrate in a back and forth linear motion. The substrate carriers 120a,b abrade the surface of the substrates 140a,b by rubbing the substrates against two different regions of the polishing pad 112.

During, before or after polishing, first and second slurry dispensers 122a,b provide polishing slurry, neutralizing solution, and/or water to the surface of the polishing pad 112. In one version, the first and second slurry dispensers 122a,b are positioned abutting the polishing platen 110. The dispensers 122a,b can also be located across the platen 110 and diametrically opposing one another. The opposing pair of slurry dispensers 122a,b are each located so that they can rotate and be positioned between the first and second substrate carriers 120a,b. In one version, the dispensers 122a,b sweep in an arc across the polishing platen 110 while dispensing slurry. Each slurry dispenser 122a,b feeds fresh polishing slurry to a different region of the polishing pad 112 that is located immediately before one of the substrates 140a, b mounted on the substrate carriers 120a, b. In this manner, the first slurry dispenser 122a provides fresh slurry to the substrate 120b on the second substrate carrier 120b and the second slurry dispenser 122b provides fresh slurry to the substrate 120a on the first substrate carrier 120a, or vice versa, depending on the direction of rotation of the polishing platen 110. Advantageously, this allows the polisher 100 to polish both substrates 140a, b at approximately the same polishing rates because fresh polishing slurry is dispensed at different circumferential regions across the polishing pad 112 that each lie between the first and second substrate carriers 120a,b.

The first and second slurry dispensers 122a,b each comprise a dispenser arm 123a,b which has a pivoting end 126a,a' and a distal end 126b,b', respectively. Each pivoting end 126a,a' of the slurry dispenser arms 123a,b is mounted on a rotatable axle 127a,b. A dispenser drive 128a, b powers the rotatable axle 127a, b to rotate each dispenser arm 123a, b about their pivoting ends 126a, a' to swing the respective slurry dispensing nozzles at the distal ends of the arms 123a,b to dispense slurry across the polishing platen 110. The dispenser drives 128a,b can be operated to rotate the dispenser arms 123a,b so that the pivoting ends 126a,a' rotates along a fixed arc across different regions of the polishing platen 110. The dispenser drives 128a,b are capable of rotating each arm 123a,b to sweep each arm in an arc across the polishing platen 110 while dispensing slurry. In one embodiment, each arc covers an arcuate distance that spans from about 0° to about 45°. The first and second fixed arcs can oppose one another across a diameter of the polishing pad 112.

At least one slurry dispensing nozzle 124a,b is provided between the pivoting end 126a, a' and the distal end 126b,b' of each of the dispenser arms 123a,b, respectively, as shown in FIG. 2. When a dispenser drive 128a rotates a particular dispenser arm 123a along an arc, the slurry dispensing nozzle 124a is also swung along a fixed arc 129 to distribute the slurry on the polishing pad 112 within the arcuate region 133a. The dispenser drives 128a,b are each capable of rotating one of the dispenser arms 123a,b about the pivoting end 126a, a' so that the nozzles 124a,b are each swung along a fixed arc 129a,b. The fixed arc 129a,b can intersect a diameter of the platen 110. In one embodiment each fixed arc 129a,b bisects a fixed radial axis 134 of the platen 110 at least twice when starting from a first position, moving to a second position across the arc, and returning to the same first position. In this manner, the polishing slurry is dispensed by rotating the dispenser arms 123a,b about two different pivot points that oppose one another across the polishing pad 112. Thus slurry is dispensed simultaneously from different points that are spaced apart from one another across the polishing pad 112 and that even can be aligned along a common axis which is a particular diameter of the platen. A suitable dispenser drive 128a,b can be a motor such as a servomotor with gear reduction or a direct drive motor, or a hydraulic system that can extend and retract to move the dispenser arms 123a,b. The first and second arcs can be fixed arcs, and they can also diametrically oppose one another across the polishing platen 110. The arcs lie between the first and second substrate carriers 120a,b, and provide fresh polishing slurry to each of the first and second substrate carriers 120a,b.

The slurry dispensers 122a,b can also comprise at least a first nozzle 124a, a' and a second nozzle 124b', b', respectively. Each of the first and second nozzles 124a,a' and 124b,b' are spaced apart from one another, and can also be aligned along a common axis that is along the longitudinal direction of the arms 123a,b. The dispensing nozzles 124a,a' and 124b,b' direct fluid, such as polishing slurry, onto the polishing pad 112 to distribute polishing slurry across a larger surface of the polishing pad 112 in the desired spray coverage area 133a,b. Referring to FIG. 3, the dispenser arm 123 includes a hollow casing 135 that surrounds and protects a plurality of supply tubes 125a-c which each provide a passage for polishing slurry, neutralizing fluid, or water, across the length of the dispenser arm 123. For example, the supply tube 125a can be used to supply polishing slurry to a barrel reservoir 137 which feeds the nozzles 124a-e. Each nozzle 124a-e is attached to a supply tube 125a by a convenient method. For example, preformed nozzles 124a-e can be attached to a fluid supply tube 125a using male and female screw threads or with rubber gasket seal. The fluid supply tubes 125a-c are made of a material that is resistant to corrosion or chemical reaction by the desired supply fluid, or even comprise a material that is capable of reduced buildup of deposits on the fluid-contacting surfaces. It is further desirable for the fluid supply tube to be flexible, such that it can withstand bending and flexing when the slurry arm is rotated. An exemplary embodiment of a fluid supply tube can be, for example, THV tubing such as THV x50 UHP available from Dyneon of Oakdale, Minnesota. Each fluid supply tube 125a-c is provided with fluid by a fluid supply source (not shown) located externally to the polisher 100. The fluid supply source can comprise a pressurized tank, chemical delivery unit or drum with pump and can supply slurry, chemical or water. One or more valves, pressure sensors and volumetric flow meters can also be used in between the fluid supply source and the supply arm to control the supply of fluid.

The embodiment of the slurry dispenser 122 shown in FIG. 3, comprises a plurality of nozzles 124a-e. Each nozzle 124a-e has a terminus opening of from about 0.03" to about 0.05". The nozzles 124a-e can also have a cross-section with a conical profile to output pressurized fluid in a conical spray pattern. A suitable conical profile comprises an angular width of from about 40° to about 120°. The nozzles 124a-e can be made by drilling holes in a tube made from a material that is resistant to erosion by, and reaction with, the desired polishing slurry composition. The nozzles 124a-e can also be formed from material that withstands buildup of deposits on the fluid-contacting surfaces of the nozzles. In one embodiment, the nozzles 124a-e are made from PVDF. In an alternative embodiment, the nozzles 124a-e are separately made and are attached to the dispenser arm 123 by screw threads or adhesive sealants. An exemplary preformed nozzle 124a-e is the VeeJet Spray Nozzle, available from: Spraying Systems Co. of Carol Stream, Illinois. The plurality of nozzles 124a-e can also be located in a slurry dispenser channel 137 that is affixed along the length of the dispenser arm 123 to disperse slurry across the polishing pad 112. The dispenser channel 137 comprises a hollow rectangular body that is disposed along the underside of the dispenser arm 123 such that the longitudinal axis of the channel is substantially parallel to the longitudinal axis of the hollow body. The dispenser channel 137 comprises one or more integral slurry dispensing nozzles 124a-e that can be formed, for example, by machining or drilling a nozzle shaped opening into the dispenser channel 137. Each shaped opening of the nozzles 124a-e can have, for example, a conical profile that tapers outward with a smaller first opening facing the internal volume of the channel 137 and a larger second opening at the exterior surface of the channel 137 (not shown). For example, the shaped opening can have a first opening diameter of less than 1 mm, and a second opening diameter of greater than about 1.1 mm. The shaped openning opens toward the platen surface and comprises a diameter of from about 1 mm to about 2 mm. The first opening of the dispenser channel can also be sufficiently large to fit over the diameter of a corresponding opening of the fluid supply tube 125a which supplies polishing slurry to the dispenser channel.

As a substrate 140 and polishing pad 112 are rotated against each other, measured amounts of polishing slurry supplied according to a selected slurry recipe are sprayed onto the polishing pad through the nozzles 124a-e. The polishing slurry contains a reactive agent and a chemically reactive catalyst. For example, an oxide substrate can be polished with polishing slurry comprising deionized water - which is used as the reactive agent, and potassium hydroxide - which serves as the catalyst. Suitable polishing slurries may also comprise, for example, abrasive particles comprising at least one of aluminum oxide, silicon oxide, silicon carbide, or other ceramic powders; and which are suspended in a solution comprising for example, one or more of water, alcohol, buffering agents and suspension chemicals. The dispenser arm 123 of the slurry dispenser 122 also includes a separate set of rinsing nozzles 138a-g which provide a rinsing fluid for rinsing a substrate 140 after a polishing process. The rinsing nozzles 138a-g are spaced apart from one another and can provide a high-pressure fluid rinse of the polishing pad 112 at the end of each polishing and/or conditioning cycle. The rinsing fluid is supplied to the rinsing nozzles 138a-g through the supply tube 125c. A rinsing fluid such as deionized water can be used to clean a substrate 140 as it passes from one polishing station to another. The rinsing nozzles 138a-g can also direct streams of water toward the slowly rotating polishing pad 112 to rinse slurry from the polishing pad surface while a substrate 140 is being transferred back to a holding station. Water can also be supplied to the surface of the polishing pad 112 to rinse particles and chemicals from the pad surface between processing of substrates 140. The rinsing step can be performed after polishing a predetermined number of substrates 140 or at the beginning of the polisher operation as a pretreatment step, at the end of operation to remove reactants from the pad surface or on an as-needed basis to rinse particles and chemicals from the pad surface. The rinsing nozzles 138a-g can also comprise conical cross-sections to supply a conical spray section of water or other cleaning fluid to the polishing pad 112. A rinsing fluid shield (not shown) can be used to cover the sides of the rinsing nozzles 138a-g to contain the spray of the rinsing fluid over the substrate. The rinsing fluid shield can be made from Teflon®, DuPont de Nemours Co., Delaware. The dispenser arm 123 of the slurry dispenser 122 can also include a chemical rinse nozzle 139 which disperses a chemical agent across the polishing pad 112 to neutralize the active agent of the polishing slurry after the polishing of one or more substrates 140 is completed. While the chemical rinse nozzle 139 is described as a separate nozzle from the slurry dispensing nozzle 124, it can also be the same nozzle structure. In one embodiment, the chemical rinse nozzle 139 is located at the distal end 126b of the dispenser arm 123. The composition of the chemical rinse is selected to stop the reaction of the chemically active components of the polishing slurry with the substrate 140 being polished, and can serve to neutralize the etchant or corrosive properties of the active slurry components. For example, in one embodiment, the chemical rinse comprises an acid or ammonia based neutralizing agent.

A controller 188 comprises suitable programming code 190 to control the CMP apparatus 100 and its various components, including the slurry dispenser 122, as shown in FIG. 4A. The controller 188 is a programmable computer comprising a CPU, an input device 192 such as a mouse, keyboard, and light pen, and an output device 194 such as a display. The controller 188 is used to calculate and measure polishing parameters and hold recipes for any of the polisher stations 108. In one embodiment, the program code 190 comprises code to control motors of the dispenser arm 123. For example, the code can control a dispenser drive 128 that powers a rotatable axle 127 to rotate each dispenser arm 123 about their pivoting ends 126 to swing the respective slurry dispensing nozzles at the distal ends of the arms 123 to dispense slurry across the polishing pad 112. The controller 188 can operate the motors of the dispenser arm 123 to obtain the desired movement of the arm 123. This movement is controlled to control the motion of the slurry dispensing nozzles 124a-c located at the distal end 126 of the arm 123 to dispense slurry onto the polishing pad 112 in a desired pattern or region. For example, the controller 188 can comprise program code to control the motors to move the dispenser arm 123 across the polishing pad 112 to obtain a desired shape of a slurry distribution region across the pad 112.

In an alternate embodiment of a slurry dispenser 122, features of which can occur on its own or in combination with any other features described herein, the dispenser arm 123 comprises a distal end 131 that is movable in a linear motion with respect to a proximal end 141 , as shown in FIGS. 5A to 5C. The distal end 131 moves linearly with respect to the proximal end 141 , for example, in a back and forth sweeping motion. In this manner, the dispensing nozzles 124a-c located on the movable segment of the dispenser arm 122 can supply a polishing slurry across a radial length of to the polishing pad 112 to cover a greater surface area of pad. In this version, the segment of the dispenser arm 123 that includes the distal end 131 is connected to a dispenser drive 143 which can move the distal end 131 towards and away from the proximal end 141 of the dispenser arm 123 along a linear path. The dispenser drive 143 moves the distal end of the arm along a linear path to dispense slurry in a line across the polishing platen. The linear motion can match the line corresponding to the longitudinal axis of the dispenser arm 123. The dispenser drive 143 is controlled by the controller 188, which comprises program code to control the linear motion of the dispenser arm 123. The distal end 131 can travel a linear distance of from about 20% to about 90% of the length of the un- extended dispenser arm 123. Coiled supply tubes 145a,b extend through the length of the dispenser arm 123 to supply polishing slurry, suspension or other fluids to the nozzles 124a-c, as shown in FIGS. 5B and 5C. The coiled supply tubes 145a,b allow the length of the arm 123 to be altered without altering the supply of fluids to the nozzles 124a-c. The coiled supply tubes 145a,b can be made of a material that is resistant to corrosion or chemical reaction by the desired supply fluid, or can even comprise a material that is capable of reduced buildup of deposits on the fluid- contacting surfaces. It is further desirable for the fluid supply tube to be flexible, such that it can withstand bending and flexing. The supply tube can be, for example, THV tubing such as THV x50 UHP available from Dyneon. Each coiled supply tube 145a, b is provided with fluid by a fluid supply source (not shown) located externally to the polisher 100. In a prospective embodiment, the controller 188 comprises program code 190 to control the movement of the distal end 131 of the dispenser arm 123 in relation to the movement of a substrate carrier 120. For example, the distal end 131 of the dispenser arm 123 can be moved into position and slurry dispensed to a substrate contact region 147 of the polishing pad 112 immediately prior to contact of this region of the pad, with a substrate 140 held by a substrate carrier 120 (not shown). The distal end 131 of the dispenser arm 123 can be positioned out of the path of the substrate carrier 120 to avoid collision with the carrier assembly. The dispenser arm 123 can supply polishing slurry to a larger area of the polishing pad 112 using a linear sweep that traverses the entire length, or a substantial portion of the radial length, of the platen or pad, as compared to a non-mobile arm. The linear sweep arm can be configured to supply a polishing slurry along a liner path that traverses from the central region of the polishing pad 112 to the perimeter of the pad. Further, since the nozzles 124a-c located about the distal end 131 of the polishing arm 123 can be moved into a radial feeding position above the polishing pad 120, the flow requirements on the polishing slurry are not as stringent. For example, partial clogging of the nozzles 124a-c and sputtering of slurry from the dispenser nozzles, which would result in uneven distribution of polishing slurry, does not have as much of an effect because the nozzles 124a-c are located closer to the target area and slurry dispensed by the nozzle, however uneven, will still land on the polishing pad 112 in the substrate contact region 147.

The polishing system can comprise first and dispenser arms 123a, 123b as shown for example in FIG. 5A. First and second dispenser arms 123a,b can be configured to oppose one another, for example the proximal end 141a of a first dispenser arm 123a can be located on the opposite side of the platen from a proximal end 141 b of a second dispenser arm 123b. First and second dispenser arms 123a,b can be configured to provide polishing slurry or other fluids to the polishing pad 112 over a larger area than a single dispenser arm 123. Further, opposing first and second dispenser arms can be configured to selectively dispense polishing medium, rinsing fluid, neutralizing chemical fluids or other fluid compositions. In one prospective embodiment, a first dispenser arm 123a is configured to dispense a polishing slurry and a second dispenser arm 123b is configured to dispense a rinsing fluid and a neutralizing chemical fluid. In this prospective embodiment the first dispenser arm 123a can be removed from the chamber for cleaning of dispenser valves that are clogged with polishing slurry without necessitating removal of the remaining dispenser arm 123b or disconnection of the other fluid supply lines.

A first slurry dispenser and dispenser arm 123a can be provided to supply polishing slurry or other fluids to a first substrate contact region and a second slurry dispenser and dispenser arm 123b is provided to supply polishing slurry or other fluids to a second substrate contact region, the first and second contact regions being different from each other. A first substrate carrier contacts a substrate to the first substrate contact region and a second substrate carrier contacts a substrate to the second substrate contact region. In this manner the first and second slurry dispenser arms 123a,b supply slurry to first and second substrate carriers.

In another prospective embodiment, the slurry dispenser 180 comprises a hinged arm 182 comprising a plurality of sections 184a-c that are joined by one or more hinged joints 186a- c, as shown in FIG. 6A. Any of sections can be moved relative to each other, for example, the first section 184a can be moved relative to the second section 184b, or both sections can be simultaneously moved. Each section 184a-c can have two, or even three, degrees of freedom of movement. The sections 184a-c can include first and second sections 184a,b which are connected at a second hinged joint 186b, and optionally, a third section 184c connected at a third hinged joint 186c. Any of the first, second and third hinged joints 186a-c can be planar joints having two degrees of freedom, pivoting ball joints having three degrees of freedom, combinations of these joints, or other types of joints. The hinged arm 182 can also have additional or fewer sections. The number of sections 184a-c and the type of hinged joints 186a-c are selected to obtain desired degrees of freedom of movement of the hinged arm 182. Further, by selecting particular combinations of the number of sections 184a-c and hinged joints 186a-c that provide different degrees of freedom, the hinged arm 182 can be tailored to provide a desired slurry distribution pattern or shaped region.

In addition, one or more of the hinged joints 186a-c can contain motors (not shown) which allow a preprogrammed range of motion of any of the sections 184a-c that are joined to a particular hinged joint 186a-c. The motors driving the sections 184a-c, and the hinged arm 182, can be micro motors located inside the hinged joints 186a-c, hydraulic motors, and other motors.

In one version, the hinged arm 182 comprises a pivoting end 190 attached to the tabletop at a first joint, and a distal end 192 with one or more slurry dispensing nozzles 202a-c at or near the distal end 192 that can be used to dispense slurry onto the polishing platen or polishing pad 112. A controller 188 comprises suitable programming code to control the motion of the slurry dispenser 122. The controller 188 is a programmable computer comprising one device or multiple devices that can be used to calculate and measure polishing parameters and hold recipes for any of the polisher stations 108. In one embodiment, the controller 188 comprises program code to control one or more the various motors of the hinged arm 182 to obtain the desired linear or arcuate movement of the plurality of sections 184a-c that are joined by one or more hinged joints 186a-c. This movement is controlled to control the motion of the slurry dispensing nozzles 202a-c located at the distal end 192 of the hinged arm 182 to dispense slurry onto the polishing pad 112 in a desired pattern or region. For example, the controller 188 can comprise program code to control the motors to move the hinged arm 182 across the polishing pad 112 to obtain a desired shape of a slurry distribution region across the pad 112.

In addition to horizontal sweep, the hinged arm 182 can also change the height of the dispensing nozzles 202a-c above the polishing pad 112, as shown for example in FIG. 7, which shows the hinged arm 182, sections 184a-c, joints 186b,c and nozzles 202a-c in a first position and in a second position as hinged arm 182', sections 184a'-c', joints 186b',c' and nozzles 202a'-c'. In this version joint 186a is located at the pivoting end 190 of the arm, such that the body of the joint 186a does not change location when the joints of the hinged arm 182 are operated. In a first position, each nozzle 202a-c of the hinged arm 182 has a conical spray area 204a-c that a pressurized fluid will be dispensed to the polishing pad 112. In a second position each nozzle 202a'-c' has a different conical spray area 204a'-c'. In the example shown, the first spray areas 204a-c are several times larger than the second spray areas 204a'- c'. This allows for the spray area of a nozzle to be altered without changing the pressure of the fluid supply. Further, coverage of the polishing pad 112 with dispensed fluid can be tailored to match contact areas of the polishing pad 112 and the substrate 140. This can be beneficial, for example, if the polishing pad 112 is sufficiently large compared to the substrate 140 such that each substrate 140 contacts only a small portion of the polishing pad surface during processing.

In one version, first and second slurry dispensers 122a,b are positioned abutting and across the polishing platen 110 to dispense slurry simultaneously from two different points that are spaced apart from one another and across the polishing platen. For example, the first and second slurry dispensers 122a,b can be positioned diametrically opposing one another as shown. In one version, the opposing pair of slurry dispensers 122a,b are positioned between the first and second substrate carriers 120a,b that are used to polish two substrates 140a, b at the same time, so that each slurry dispenser 122a,b can provide polishing slurry to a different region of the polishing pad 112 that is located in the immediate path of substrate carrier 120a,b. For example, the first and second substrate carriers 120a,b, can be moved to dispense slurry at a first point that lies before the first substrate carrier 102a and at a second point that lies before the second substrate carrier 120b. In this manner, the first slurry dispenser 122a provides fresh slurry to the second substrate carrier 120b and the second slurry dispenser provides fresh slurry to the first substrate carrier 120a, or vice versa, depending on the direction of rotation of the polishing platen 110. Advantageously, this allows the polisher 100 to polish both substrates 140a,b at approximately the same polishing rates because fresh polishing slurry is dispensed at different circumferential regions across the polishing pad 112 that each lie between the first and second substrate carriers 120a,b.

In one embodiment, the hinged arm 182 comprises first, second and third sections 184a-c which are joined together by the first and second intermediary joints 186b,c. The first section 184a is attached to the tabletop 106 at a first joint 186a which is a pivoting joint, such as a ball joint, to provide a pivoting end 190 that allows the hinged arm 182 to rotate about the pivoting joint. A second section 184b lies in-between the first section 184a and a third section 184c. One or more slurry dispensing nozzles 200a, b are positioned at a distal end 192 of the hinged arm 182 on the third section 184c.

The flexibility of the hinged arm 182 and the distal location of the slurry dispensing nozzles 200a, b allow dispersion of polishing slurry in an optimal dispersion or sweep pattern which is not dependant upon or tied to the shape or size of the polishing pad 112. For example, the hinged arm 182 can be readily adapted to dispense polishing slurry across a rectangular or even square polishing pad 112. Further, the hinged arm 182 can also be can be controlled by the controller 188 to achieve the desired linear or arcuate pattern to provide an elongated slurry distribution region. For example, the hinged arm 182 can be readily adapted to move the dispensing nozzles 202a-c along a linear path across the polishing platen. In one version, the motors of the hinged arm 182 so that the slurry dispensing nozzles 202a-b move along a straight line across the platen or polishing pad. In another version, the motors of the hinged arm 182 move the slurry dispensing nozzles 202a-b along an arcuate path across the platen or polishing pad. For example, the arcuate path can comprise a fixed arc that bisects a fixed radial axis of the polishing platen 110 at least twice. The arcuate path can be also set to cover, for example, an arcuate distance that spans from about 0° to about 45° across the polishing platen 110.

The embodiment of the slurry dispenser 122 shown in FIG. 6A, comprises a plurality of nozzles 202a-c. Each nozzle 202a-c has a terminus opening of from about 0.03" to about 0.05". The nozzles 202a-c can also have a cross-section with a conical profile to output pressurized fluid in a conical spray pattern. A suitable conical profile comprises an angular width of from about 40° to about 120°. The nozzles 202a-c can be made by drilling holes in a tube made from a material that is resistant to erosion by, and reaction with, the desired polishing slurry composition. The nozzles 202a-c can also be formed from material that withstands buildup of deposits on the fluid-contacting surfaces of the nozzles. In one embodiment, the nozzles 202a-c are made from PVDF. In an alternative embodiment, the nozzles 202a-c are separately made and are attached to the dispenser arm 182 by screw threads or adhesive sealants. An exemplary preformed nozzle 202a-c is the VeeJet Spray Nozzle, available from: Spraying Systems Co. (Spraying Systems Co., North Avenue at Schmale Road, Carol Stream, Illinois).

In one version, the sections 184a-c of the hinged arm 182 each comprise a tubular section 208 comprising a hollow casing, as shown in FIG. 6B. The tubular section 208 surrounds and protects a plurality of supply tubes 206a-c which each provide a passage for polishing slurry, neutralizing fluid, or water, across the length of the hinged arm 182. For example, the supply tube 206a can be used to supply polishing slurry to a slurry dispensing nozzle 202a. Each nozzle 202a-c is attached to a supply tube 206a-c by a convenient method. For example, preformed nozzles can be attached to a fluid supply tube 206a-c using male and female screw threads or with rubber gasket seal. The fluid supply tubes 206a-c are made of a material that is resistant to corrosion or chemical reaction by the desired supply fluid, or even comprise a material that is capable of reduced buildup of deposits on the fluid-contacting surfaces. It is further desirable for the fluid supply tube to be flexible, such that it can withstand bending and flexing when the hinged arm is operated. An exemplary embodiment of a fluid supply tube can be, for example, THV tubing such as THV x50 UHP available from Dyneon, (city, state).

Each fluid supply tube 200a-c is provided with fluid by a fluid supply source (not shown) located externally to the polisher 100. The fluid supply source can comprise a pressurized tank, chemical delivery unit or drum with pump and can supply slurry, chemical or water. One or more valves, pressure sensors and volumetric flow meters can also be used in between the fluid supply source and the supply arm to control the supply of fluid.

Nozzles of the hinged arm 182 can be operated to dispense fluids in relation to a polishing process. The nozzles 202a, b can be used to dispense measured amounts of slurry to the polishing pad according to a selected recipe. The hinged arm 182 can also include one or more separate rinsing nozzles 202c which provide a rinsing fluid for rinsing the polishing pad 112 after a polishing process. A high-pressure fluid rinse of the polishing pad 112 can even be performed at the end of each polishing and/or conditioning cycle. The rinsing fluid is supplied to the rinsing nozzles through the supply tube 200c. The hinged arm 182 of the slurry dispenser 122 can include a chemical rinse nozzle (not shown) which disperses a chemical agent across the polishing pad 112 to neutralize the active agent of the polishing slurry after the polishing of one or more substrates 140 is completed. While the chemical rinse nozzle is described as a separate nozzle from the slurry dispensing nozzle, it can also be the same nozzle structure. In one embodiment, the chemical rinse nozzle is located at the distal end 192 of the hinged arm 182. The nozzles disclosed in reference to hinged slurry dispenser 180 can be made of the same materials as the corresponding slurry dispenser, rinsing and chemical rinse nozzles disclosed in reference to rotating slurry dispenser 122. Further, the fluids dispensed by and pressures supplied to corresponding nozzles of the different versions of the slurry dispenser 122, 180 can also be the same. The different versions of the slurry dispensers described herein can be used in any type of CMP polisher. For example, an embodiment of a chemical mechanical polisher 100 that can be used to planahze a surface of a semiconductor wafer substrate, is shown in FIGS. 4A to 4C. The polisher 100 is provided to illustrate use of any of the different embodiments of the slurry dispensers; however, the polisher 100 should not be used to limit the scope of the present invention. The polisher 100 may be, for example, a Mirra® or Sycamore® type CMP system from Applied Materials, Inc., Santa Clara, California. Generally, the polisher 100 includes a housing 104 containing a tabletop 106 one or more polishing stations 108a,b, a substrate transfer station 111 , and a rotatable multi-head carousel 116 that operates independently rotatable substrate carriers 120, as shown in FIG. 4A. Each polishing station 108a,b includes a rotatable polishing platen 110a,b having a polishing pad 112a,b disposed thereon. The platens 110a,b can be a rotatable aluminum or stainless steel plate connected to a platen motor (not shown). The polishing pads 110a,b can include fixed-abrasive or non-abrasive pads. The polishing slurry is dispensed onto a pads 112a,b by the slurry dispenser 122a,b. Each polishing station 108 can also have one or more pad conditioners 114 which has a rotatable arm 118 that holds an independently rotating conditioner head 119 as shown, for example, in FIG. 6A. The pad conditioner 114 maintains the condition of the polishing pad 112 to allow the pad to effectively polish the substrates 40. Each pad conditioner head 119 comprises a platen that holds an abrasive disc (not shown). The platen is a support structure, such a carbon steel plate, which provides structural rigidity to the abrasive pad. The abrasive disc comprises an exposed abrasive face of a metal alloy, such as a nickel or cobalt alloy, having abrasive particles embedded in the metal alloy. The polishing stations 108 having fixed- abrasive pads do not require a pad conditioner since fixed-abrasive pads generally do not require conditioning. The conditioner head 119 sweeps the abrasive disc across the polishing pad 112 with a reciprocal motion that is synchronized with the motion of the substrate carrier 120 across the polishing pad. The pad conditioner shown in FIG. 4C is mounted at a first height from the tabletop 106 that is higher than a second height of the first and second slurry dispensers. The first height can be higher than a second height by at least about 15mm. This version allows the pad conditioner to sweep over the slurry arm, reducing polisher footprint. Referring back to FIG. 4A, a substrate loading apparatus 130 includes a cassette 136 containing a batch of substrates 140. An arm 144 rides along a linear track 148 and supports a wrist assembly 152, which includes a cassette claw 154 for moving cassettes 136 from a holding station 155 and a substrate blade 156 for transferring substrates 140 from the cassette 136 to the transfer station 111. In operation, a substrate 140 is loaded from the cassette 136 to the transfer station 111 , from which the substrate is transferred to a substrate carrier 120 where it is initially held by vacuum. The carousel 116 then transfers the substrate 140 through a series of one or more polishing stations 108a,b and finally returns the polished substrate to the transfer station 111. The carousel 116 has a support plate 160 with slots 162 through which the shafts 172 of the substrate carriers 120 extend, as shown in FIG. 4B. The substrate carriers 120 can independently rotate and oscillate back-and-forth in the slots 162 to achieve a uniformly polished substrate surface. The substrate carriers 120 are rotated by respective motors 176, which are normally hidden behind removable sidewalls 178 of the carousel 116.

As shown in FIGS. 4B and 4C, each polishing station 108a-c includes a rotatable platen 110a-c that each support a polishing pad 112a-c having an overhead pair of opposing slurry dispensers 122a-c, 122a'-c', respectively. While the slurry dispensers 122a-c, 122a'-c", are shown, it should be understood that the hinged slurry dispenser 180 can be used instead, or in combination. During polishing, each substrate carrier 120 holds, rotates, and presses a substrate 140 against a polishing pad 112a-c affixed to the rotating polishing platen 110a-c. As a substrate 140 and polishing pad 112a-c are rotated against each other, measured amounts of a polishing slurry of, for example, deionized water with colloidal silica or alumina, are supplied according to a selected slurry recipe, by the polishing slurry dispensers 122a-c, 122a'-c'. Both the platen 110 and the substrate carriers 120 can be programmed to rotate at different rotational speeds and directions according to a process recipe. For visual clarity, the pad conditioners are not shown in FIG. 4B, whereas three pad conditioners 114a-c are shown in FIG. 4C. There can also be six pad conditioners 114 (not shown) each of which is mounted in relation to a slurry dispenser 122a-c, 122a'-c'.

The present invention has been described with reference to certain preferred versions thereof; however, other versions are possible. For example, the pad conditioner can be used in other types of applications, as would be apparent to one of ordinary skill, for example, as a sanding surface. Other configurations of the CMP polisher can also be used. Furthermore, alternative channel configurations equivalent to those described can also be used in accordance with the parameters of the described implementation, as would be apparent to one of ordinary skill. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.

Claims

What is claimed is:

1. A chemical mechanical polisher comprising:

(a) a polishing platen capable of supporting a polishing pad;

(b) first and second substrate carriers that are each capable of holding a substrate against the polishing pad; and

(c) first and second slurry dispensers, each slurry dispenser comprising: (i) an arm comprising a pivoting end and a distal end;

(ii) at least one slurry dispensing nozzle on the distal end; and (iii) a dispenser drive capable of rotating the arm about the pivoting end to swing the slurry dispensing nozzle at the distal end to dispense slurry across the polishing platen.

2. A polisher according to claim 1 wherein the dispenser drive is capable of at least one of the following:

(a) rotating the arm to sweep the arm in an arc across the polishing platen while dispensing slurry;

(b) rotating the arm so that the slurry dispensing nozzle is swept along a fixed arc that lies between the first and second substrate carriers and does not contact either of the substrate carriers;

(c) rotating the arm so that the slurry dispensing nozzle is swept along a fixed arc that lies between the first and second substrate carriers and does not contact either of the substrate carriers wherein the fixed arc bisects a radial axis of the polishing pad at least twice;

(d) rotating the arm along a fixed arc of from about 0° to about 45° according to a program.

3. A polisher according to claim 1 wherein the first and second slurry dispensers diametrically oppose one another across the polishing platen.

4. A polisher according to claim 1 wherein the first and second slurry dispenser can rotate such that each dispenser can be positioned between a first and a second substrate carrier to provide fresh slurry to one of the first or second substrate carriers.

5. A polisher according to claim 1 wherein the first and second slurry dispensers each comprise a plurality of slurry dispensing nozzles that are spaced apart from one other and aligned along a common axis.

6. A polisher according to claim 1 further comprising first and second pad conditioners that are mounted at a first height from the tabletop that is higher than a second height of the first and second slurry dispensers.

7. A chemical mechanical polishing method comprising:

(a) rubbing first and second substrates against a polishing pad; and

(b) dispensing polishing slurry before each of the first and second substrates.

8. A method according to claim 7 comprising dispensing slurry along first and second fixed arcs having at least one of the following characteristics:

(i) the first and second arcs each provides fresh polishing slurry to one of the first and second substrates;

(ii) the first and second fixed arcs diametrically oppose one another;

(iii) the first and second fixed arcs are spaced apart and each arc lies between the first and the second substrate;

(iv) the first and second fixed arcs are at different positions and between the first and second substrates;

(v) the first and second fixed arcs bisect a radial axis of the polishing pad at least twice; and

(vi) the first and second fixed arcs are each from about 0° to about 45°.

9. A method according to claim 7 comprising dispensing slurry simultaneously from different points that are spaced apart from one other and aligned along a common axis.

10. A chemical mechanical polisher comprising:

(a) a polishing platen capable of supporting a polishing pad;

(c) first and second slurry dispensers, each slurry dispenser comprising: (i) an arm comprising a proximal end and a distal end;

(ii) at least one slurry dispensing nozzle on the distal end; and (iii) a dispenser drive capable of moving the distal end of the arm along a linear path to dispense slurry in a line across the polishing platen.

11. A polisher according to claim 10 comprising at least one of the following:

(i) the first and second slurry dispensers are across the polishing platen;

(ii) the dispenser drive is capable of moving the distal end toward or away from the proximal end;

(iii) the dispenser drive is capable of moving the distal end along a line that corresponds to the longitudinal axis of the arm;

(iv) the distal end of the arm moves across a distance of from about 20% to about 90% of the length of the un-extended arm; and

(v) coiled supply tubes that extend through the length of the arm to supply polishing slurry, suspension or other fluids to the dispensing nozzles.

12. A chemical mechanical polisher for polishing a substrate with a slurry, the polisher comprising:

(a) a polishing platen for supporting a polishing pad;

(b) a substrate carrier capable of holding a substrate against the polishing platen; and

(c) a first slurry dispenser comprising a hinged arm comprising:

(i) a plurality of sections that are joined at one or more hinge joints;

(ii) a pivoting end and a distal end; and

(iii) at least one slurry dispensing nozzle located at or near the distal end.

13. A polisher according to claim 12 wherein the plurality of sections include at least first and second tubular sections which are connected at first and second hinged joints, the hinged joints each providing at least two degrees of freedom of movement.

14. A polisher according to claim 12 comprising first and second substrate carriers, and wherein the slurry dispensing nozzle can be moved to dispense slurry at a first point that lies before the first substrate carrier and at a second point that lies before the second substrate carrier.

15. A polisher according to claim 12 comprising a motor capable of at least one of the following:

(a) moving the hinged arm so that the slurry dispensing nozzle travels along a linear or arcuate path across the polishing platen; or

(b) moving the hinged arm so that the slurry dispensing nozzle travels across an arcuate path of from about 0° to about 45°

16. A polisher according to claim 12 further comprising a controller comprising programming code to control the motor to drive the hinged arm across the polishing platen to obtain a predetermined slurry distribution across the polishing pad.

17. A chemical mechanical polishing method comprising:

(a) rubbing a substrate against a polishing pad mounted on a polishing platen; and

(b) providing a hinged slurry dispenser arm comprising a first section and a second section that are joined to one another at hinge joints, a pivoting end, a distal end, and at least one slurry dispensing nozzle located at or near the distal end; and

(c) moving the first section relative to the second section to dispense polishing slurry in a distribution pattern across the polishing pad.

18. A method according to claim 17 comprising at least one of the following:

(a) moving both the first section and the second section;

(b) moving the slurry dispensing nozzle along a linear path across the polishing platen;

(c) moving the slurry dispensing nozzle along an arcuate path across the polishing platen;

(d) moving the slurry dispensing nozzle along an arcuate path of from about 0° to about 45° across the polishing pad;

(e) moving the slurry dispensing hinged arm across the polishing platen to obtain a slurry distribution across the polishing pad;

(f) moving the first or second section with at least two degrees of freedom of movement;

(g) dispensing polishing slurry at two locations across the polishing platen; or (h) dispensing slurry simultaneously from two different points that are spaced apart from one another and across the polishing platen.