CMP POLISHER HEAD OVER-ROTATION RESTRICTOR

Abstract

A CMP tool including a polisher head with an over-rotation restrictor mechanism is operative to counteract a rotational difference between an inner body of the polisher head and an outer body of the polisher head that are coupled by a rolling seal. In one arrangement, the over-rotation restrictor mechanism comprises a plurality of rotation lock pins provided with a rotational component of the polisher head, e.g., the outer body, and a corresponding plurality of restrictor receptacles provided with another rotational component of the polisher head, e.g., the inner body, wherein the rotation lock pins may be engaged with respective restrictor receptacles for arresting the rotational difference between the two rotational components.

Claims

1. A chemical-mechanical planarization (CMP) polisher head, comprising: an inner body configured to be driven around a rotational axis, the inner body including an annular rolling seal affixed proximate to a bottom terminus of the inner body; and an outer body disposed in a rotational union with the inner body along the rotational axis by engaging in a compressive arrangement with the annular rolling seal, wherein a plurality of rotation lock pins are fastened to an inner wall of the outer body, the plurality of rotation lock pins configured to engage with a corresponding plurality of slots disposed on an outer wall of the inner body, the plurality of rotation pins operating to arrest a rotational difference between the inner body and the outer body during a polishing operation of a top surface of a semiconductor process wafer.

2. The CMP polisher head as recited in claim 1, wherein the plurality of rotation lock pins are symmetrically positioned along a circular perimeter of the inner wall of the outer body.

3. The CMP polisher head as recited in claim 1, wherein the plurality of rotation lock pins each comprise a threaded portion and a non-threaded portion, the threaded portion configured to fasten into the inner wall of the outer body and the non-threaded portion having a form factor configured to engage with a corresponding slot in the inner body.

4. The CMP polisher head as recited in claim 1, wherein the plurality of slots each comprise a recess having a cross-sectional area with two opposing sidewalls, the cross-sectional area dimensioned to accept a corresponding rotation lock pin of the outer body.

5. The CMP polisher head as recited in claim 4, wherein at least one of the two opposing sidewalls of a slot comprises a sloped wall.

6. The CMP polisher head as recited in claim 4, wherein at least one of the two opposing sidewalls of a slot comprises a vertical wall.

7. The CMP polisher head as recited in claim 4, wherein at least one of the two opposing sidewalls of a slot comprises a curvilinear wall.

8. The CMP polisher head as recited in claim 1, wherein the inner body includes a plurality of apertures configured to support tubing for facilitating multi-zonal control of a membrane affixed to a retainer ring coupled to the outer body, the membrane operative to pneumatically attach to a backside of the semiconductor process wafer.

9. A chemical-mechanical planarization (CMP) tool, comprising: a CMP polisher head configured to rotate around a first rotational axis; a platen having a polishing pad disposed thereon, the platen configured to rotate around a second rotational axis; and a slurry dispenser positioned proximate to the platen, the slurry dispenser operative to controllably deliver a slurry material on the polishing pad, wherein the CMP polisher head comprises: a first rotational component having a flange for mounting to a spindle driven by a motor around the first rotational axis, the first rotational component having a rolling seal affixed proximate to a bottom terminus thereof; and a second rotational component axially aligned with the first rotational component along the first rotational axis, the second rotational component attached to the first rotational component by engaging in a compressive arrangement with the rolling seal, wherein a plurality of rotation lock pins and a corresponding plurality of restrictor receptacles are provided with the first and second rotational components such that the plurality of rotation pins and the plurality of restrictor receptacles operate, when respectively engaged, to arrest a rotational difference between the first and second rotational components during a polishing operation of a top surface of a semiconductor process wafer by the polishing pad disposed on the platen.

10. The CMP tool as recited in claim 9, wherein the plurality of rotation lock pins are positioned along a circular perimeter of an inner wall of the second rotational component and the corresponding plurality of receptacles are positioned in an outer wall of the first rotational component.

11. The CMP tool as recited in claim 9, wherein the plurality of rotation lock pins are positioned along a circular perimeter of an outer wall of the first rotational component and the corresponding plurality of restrictor receptacles are positioned in an inner wall of the second rotational component.

12. The CMP tool as recited in claim 9, wherein the plurality of rotation lock pins each comprise a threaded portion and a non-threaded portion, the threaded portion configured to fasten into a wall portion of the first rotational component or the second rotational component and the non-threaded portion having a form factor configured to engage with a corresponding one of the plurality of restrictor receptacles.

13. The CMP tool as recited in claim 8, wherein the plurality of restrictor receptacles each comprise a recess having a cross-sectional area with two opposing sidewalls, the cross-sectional area dimensioned to accept a corresponding rotation lock pin.

14. The CMP tool as recited in claim 13, wherein at least one of the two opposing sidewalls of a restrictor receptacle comprises a sloped wall.

15. The CMP tool as recited in claim 13, wherein at least one of the two opposing sidewalls of a restrictor receptacle comprises a vertical wall.

16. The CMP tool as recited in claim 13, wherein at least one of the two opposing sidewalls of a restrictor receptacle comprises a curvilinear wall.

17. The CMP tool as recited in claim 9, wherein the first rotational component includes a plurality of apertures configured to support tubing for facilitating multi-zonal control of a membrane affixed to a retainer ring coupled to the second rotational component, the membrane operative to pneumatically attach to a backside of the semiconductor process wafer.

18. A chemical-mechanical planarization (CMP) polisher head, comprising: an inner body configured to be driven around a rotational axis, the inner body including an annular rolling seal affixed proximate to a bottom terminus of the inner body; an outer body disposed in a rotational union with the inner body along the rotational axis; and a plurality of rotation lock pins engaged with a corresponding plurality of restrictor receptacles to arrest a rotational difference between the inner body and the outer body, the plurality of rotation lock pins and the corresponding plurality of restrictor receptacles disposed between the inner body and the outer body.

19. The CMP polisher head as recited in claim 18, wherein the plurality of rotation lock pins are symmetrically positioned along a circular perimeter of an inner wall of the outer body and the corresponding plurality of restrictor receptacles are disposed on an outer wall of the inner body.

20. The CMP polisher head as recited in claim 18, wherein the plurality of rotation lock pins are symmetrically positioned along a circular perimeter of an outer wall of the inner body and the corresponding plurality of restrictor receptacles are disposed on an inner wall of the outer body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Implementations of the present disclosure are illustrated by way of example, and not by way of limitation, in the Figures of the accompanying drawings. It should be noted that different references to “an” or “one” implementation in this disclosure are not necessarily to the same implementation, and such references may mean at least one. Further, when a particular feature, structure, or characteristic is described in connection with an implementation, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other implementations whether or not explicitly described.

[0010] The accompanying drawings are incorporated into and form a part of the specification to illustrate one or more example implementations of the present disclosure. Various advantages and features of the disclosure will be understood from the following Detailed Description taken in connection with the appended claims and with reference to the attached drawing Figures in which:

[0011] FIG. 1 depicts a representative CMP tool system having a polisher head according to some examples of the present disclosure;

[0012] FIG. 2 depicts a top-down view of an example polisher head illustrating rotational forces that may be encountered in a polishing operation;

[0013] FIG. 3 depicts an example CMP tool system illustrating a partial cutaway side view of a polisher head having an over-rotation restrictor mechanism according to some examples of the present disclosure;

[0014] FIGS. 4A and 4B depict example polisher head over-rotation restrictor configurations according to some examples of the present disclosure;

[0015] FIG. 5 depicts example rotator lock pins for purposes of some examples of the present disclosure; and

[0016] FIG. 6 depicts cross-sectional views of example restrictor receptacles operative to receive rotator lock pins of suitable form factors for purposes of some examples of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

[0017] Examples of the disclosure are described with reference to the attached Figures wherein like reference numerals are generally utilized to refer to like elements. The Figures are not drawn to scale and they are provided merely to illustrate representative examples. Numerous specific details, relationships, and methods are set forth below to provide an understanding of one or more examples. However, it should be understood that some examples may be practiced without such specific details. In other instances, well-known subsystems, components, structures and techniques have not been shown in detail in order not to obscure the understanding of the examples. Accordingly, it will be appreciated by one skilled in the art that the examples of the present disclosure may be practiced without such specific components.

[0018] In the following description, reference may be made to the accompanying drawings wherein certain directional terminology, such as, e.g., “upper”, “lower”, “top”, “bottom”, “left-hand”, “right-hand”, “front side”, “backside”, “vertical”, “horizontal”, etc., may be used with reference to the orientation of the Figures or illustrative elements thereof being described. Because components of some examples can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. Likewise, references to features referred to as “first”, “second”, etc., are not indicative of any specific order, importance, and the like, and such references may be interchanged mutatis mutandis, depending on the context, implementation, etc. Further, the features of examples described herein may be combined with each other unless specifically noted otherwise.

[0019] As used herein, the term “couple” or “couples” is intended to mean either an indirect or direct mechanical connection or attachment between two components or structures unless otherwise qualified.

[0020] Referring now to the drawings, FIG. 1 depicts a representative CMP tool or system including a polisher head with an over-rotation restrictor mechanism according to some examples of the present disclosure. CMP tool, generally denoted by reference numeral 100, may include a polishing platen 120 rotatable about a rotational axis 128 by a platen driver (not shown) coupled to a chuck 122. Platen 120 may have an upper surface on which a polishing pad 124 is mounted. In some arrangements, a polishing layer 130 may be provided with polishing pad 124 that is arranged and configured for uniformly applying a polishing medium 132 dispensed by a dispenser 140 onto polishing pad 124 during the polishing of a semiconductor process wafer (not specifically shown in this FIG.) or other work pieces, such as, e.g., magnetic information storage disks, glass works, among others, held in a polisher head 102. In some arrangements, polishing pad 124 may optionally include a plurality of grooves 126 configured for improving the utilization of polishing medium 132 as well as for enhancing the usable lifetime of polishing pad 124. Although the terms “wafer”, “semiconductor process wafer”, or “semiconductor wafer” are synonymously used in the description herein for convenience, those skilled in the art will appreciate that work pieces other than wafers are within the scope of some examples of the present disclosure.

[0021] Polisher head 102, also referred to as a wafer carrier in some arrangements, is rotatable about an axis 110 by a motor (not shown) via a suitable drive mechanism, e.g., a shaft or spindle, to which polisher head 102 may be coupled as is known in the art. Polisher head 102 may be supported above polishing layer 130, wherein a carrier support assembly (not shown in this FIG.) may be adapted to transfer the rotational drive provided by the motor to polisher head 102 along with a downward force (F) to press a top surface of the work piece against polishing layer 130 such that a desired pressure exists between the work piece that is mounted in polisher head 102 in a face-down configuration and polishing layer 130 during a polishing operation.

[0022] As noted above, dispenser 140 of CMP system 100 may be operative to supply polishing medium 132, also sometimes referred to as a “slurry”, from a reservoir (not shown) to a location adjacent polishing pad 124 where the polishing medium is dispensed onto polishing layer 130. A flow control valve (not shown) may be used to control the dispensing of polishing medium 116 onto pad 124. In general, polishing medium 132 may comprise a slurry material having a suitable composition (e.g., a colloidal composition) depending on types of material to be polished or removed. In some arrangements, slurry material may comprise a reactant, an abrasive, a surfactant, and/or a solvent, or a combination or sub-combination thereof, as well as oxidizers, organic compounds such as dispersants, passivation agents and deionized (DI) water, and the like. In some arrangements, the slurry materials may comprise a nano-sized abrasive power dispersed in a chemically reactive solution, wherein a chemical etching process is operative to soften the work piece material while a mechanical abrasion action removes the material, thus flattening the topographic features (e.g., asperities) and making the surface planar.

[0023] During the polishing operation, platen driver rotates platen 120 and polishing pad 124 and the slurry dispenser system is activated to dispense polishing medium 132 onto the rotating polishing pad. Polishing medium 132 spreads out over polishing layer 130 due to centrifugal force caused by the rotation of polishing pad 124. Polisher head 102 may be rotated at a selected speed, e.g., 0 rpm to about 300 rpm, so that work piece surface confronting polishing layer 130 moves relative thereto. In general, polisher head 102 may be controlled to provide a downward force so as to induce a desired pressure, e.g., 0 psi to 15 psi, between the work piece and polishing pad 124. In some arrangements, polishing platen 120 may also be rotated at speeds of up to 300 rpm or thereabouts. As polishing pad 124 is rotated beneath polisher head 102 containing the work piece, polisher head 102 may be configured to sweep out in a radial arc or some other polishing track, e.g., track 152, on polishing layer 130. Depending on implementation, polisher head 102 and platen 120 may be rotated in the same direction, e.g., clockwise or counterclockwise, or in opposite directions.

[0024] Although not shown in FIG. 1, some examples the CMP tool system 100 may also include a pad conditioner attached to a pad conditioner head, which may driven by a pad conditioner arm in a sweeping motion across a region of polishing pad/layer arrangement 124/130. In some examples, the pad conditioner may comprise a substrate over which an abrasive material may be provided for removing any built-up debris and excess slurry from polishing pad/layer arrangement 124/130 of CMP tool system 100. In some examples, the pad conditioner may also be configured to operate as an abrasive for polishing pad/layer 124/130 to achieve a desired texture and/or thickness against which the work piece may be polished.

[0025] In one implementation, polisher head 102 may comprise a two-component arrangement wherein a first component and a second component may be disposed in a rotational union such that they rotate around a common rotational axis, e.g., axis 110. In such an arrangement, an inner body 104 may be provided as one of the components (e.g., a first or second component) whereas an outer body 106 may be provided as the other component (e.g., a second or first component, depending on how inner body 104 is designated), wherein a rolling seal (not shown in this FIG.) affixed to or otherwise provided with inner body 104 may be configured to operate as an attachment mechanism between inner body 104 and outer body 106 suitable for transferring rotational force(s) therebetween. In some arrangements, outer body 106 may include or otherwise be provided with a membrane 108 that may be configured to provide a pneumatic-based attachment (e.g., a vacuum attachment) to a backside of the work piece, e.g., a backside surface of the substrate of a semiconductor process wafer. In some arrangements, a retainer ring (not shown in this FIG.) may be provided as part of or otherwise coupled to outer body 106 to provide a housing for holding membrane 108 as is known in the art. In still further arrangements, inner body 104 may be provided with a plurality of apertures 105 configured to support tubing for facilitating multi-zonal control of membrane 108 (e.g., pneumatic control) such that the work piece may be oriented in multiple ways (e.g., tilted or swiveled) in order to achieve differential planarization or material removal across the surface area(s) of the work piece.

[0026] Depending on implementation, an example of CMP tool system 100 may be adapted to process dielectric layers including inter-layer and inter-metal dielectrics (ILDs/IMDs) (e.g., silicon dioxide, silicon nitride, etc.), metal and metal interconnect layers such as tungsten, aluminum, copper, etc., as well as for forming shallow trench isolation (STI) structures, polysilicon via plugs, and carbon nanotubes, etc.

[0027] As illustrated in FIG. 1, CMP tool system 100 is exemplified with an arrangement including a single polisher head (e.g., polisher head 102) and a single polishing pad (e.g., polishing pad 124). However, the teachings of the present disclosure are not limited to such an arrangement and, in other examples, a CMP tool system may be configured as an apparatus having multiple polisher heads (e.g., head assemblies) and/or multiple polishing pads. Regardless of how many polisher heads are configured in a CMP tool, one or more polisher heads may be provided with an over-rotation restrictor mechanism according to examples herein as will be set forth in further detail below.

[0028] FIG. 2 depicts a top-down view of an example polisher head illustrating rotational forces that may be encountered during polishing operations. Polisher head 200 is exemplified with an inner body or component 202 having an annular rolling seal 208 and an outer body or component with a retainer ring, collectively referred to as outer body/retainer ring (OBRR) subassembly 206 for convenience, wherein inner body 202 and subassembly 206 may be attached together mechanically by way of a compressive fit arrangement facilitated by rolling seal 208. Polisher head 200 is rotatable around a vertical axis 204 in a clockwise and/or counterclockwise direction as noted previously. Rolling seal 208 may be configured to seal between two moving components, i.e., inner body 202 and OBRR subassembly 206, as well as facilitate the transfer of rotational motion and torsional loads therebetween. Depending on implementation, rolling seal 208 may be formed from a variety of polymer materials having a range of hardness specifications (e.g., in durometer numbers), thermo-mechanical properties, and thicknesses (e.g., in the range of one or several millimeters). By way of illustration, rolling seal 208 may comprise polymer materials including, without limitation, acrylonitrile, butadiene nitrile, polychloroprene rubber, flurosilicone rubber, hydrogenated nitrile, polysilicone, etc., having a durometer hardness in the range of 45-90.

[0029] During polishing operations, the retainer ring of OBRR subassembly 206 may experience or generate a frictional force in one direction, e.g., circular friction 212, whereas inner body 202 is under a rotational torque 210 in an opposite direction, as illustrated in FIG. 2. Accordingly, rolling seal 208 may experience two opposing forces simultaneously that can cause opposing deformations in the polymer material of rolling seal 208, thereby increasing the risk of structural damage (e.g., fraying, tearing, perforations, etc.) to the material. Further, such forces may be particularly caused or exacerbated during certain CMP processes that may generate excessive torque on the polisher head, e.g., dechucking of a wafer. For example, the retainer ring of polisher head 200 may continue to be pressured during dechucking in order to keep the wafer captured in the polisher head while a vacuum is created inside the polisher head to pull the membrane attached to the wafer's backside surface so that the upside down top surface of the wafer comes off the polishing pad disposed underneath the polisher head. Due to the texture of the polishing pad and/or because of consumption and deterioration of the pad material over time, the surface of the polishing pad may contain small depressions, grooves or channels, etc., that do not allow the slurry material to penetrate properly, thereby causing small pockets of vacuum to be formed on the polishing pad surface. Such vacuum pockets on the polishing pad surface operate to create a downward force opposing the pulling force applied in the polisher head to remove the wafer from the polishing pad. To compensate for the opposing downward force, an excessive drive current may be utilized by the motor driving the polisher head, which can create an excessive torque or “over-rotation” that is transmitted to the inner body, thereby causing a rotational difference between the inner body and the OBRR assembly. As the rotational difference between the inner body and OBRR components of the polisher head generates the countervailing rotational torque experienced by the rolling seal, the risk of functional failure of the rolling seal is increased in such conditions, thereby requiring the polishing head to be replaced and/or possibly resulting in wafer scrap or reworking due to less than desired polishing performance.

[0030] Further, different over-rotation conditions may be generated in CMP processes depending on a number of factors such as, consumables used, e.g., slurries, pad materials, etc., rotational speeds of the polish heads and/or platens, polishing recipes (e.g., polishing time durations including the durations of wafer dechuck operations, etc.), materials to be removed or polished, and the like, resulting in a host of potentially low efficiency processing stages in a semiconductor fabrication flow.

[0031] Examples of the disclosure are directed to a CMP tool and polisher head system having a mechanical over-rotation restrictor mechanism that is configured to eliminate, limit or reduce the amount of rotational difference between the inner and outer bodies of the polisher head, whereby the foregoing deficiencies are advantageously mitigated. Broadly, an example of the over-rotation restrictor mechanism may be implemented as a combination of a plurality of rotation lock pins and a corresponding plurality of restrictor receptacles that may be provided with a first and second rotational bodies (i.e., an inner body and an outer body) of the CMP polisher head, such that the plurality of rotation pins and the plurality of restrictor receptacles operate, when respectively engaged, to arrest a rotational difference between the first and second rotational components during a polishing operation of a top surface of a semiconductor process wafer by the polishing pad disposed on the platen. In one arrangement, the plurality of rotation lock pins may be positioned along a circular perimeter of an inner wall of the outer body (e.g., the second rotational component) and the corresponding plurality of receptacles are positioned in an outer wall of the inner body (e.g., the first rotational component). In another arrangement, the plurality of rotation lock pins may be positioned along a circular perimeter of an outer wall of the first rotational component (e.g., the inner body) and the corresponding plurality of restrictor receptacles are positioned in an inner wall of the second rotational component (e.g., the outer body). In another arrangement, the rotation lock pins and corresponding receptacles may be distributed between the inner and outer bodies in any combination for effectuating respective mating engagements therebetween, e.g., a first set of rotation lock pins provided with the outer body and a second set of rotation lock pins provided with the inner body, and a corresponding first set of receptacles provided with the inner body as well as a corresponding second set of receptacles provided with the outer body.

[0032] Regardless of where the rotator lock pins and corresponding restrictor receptacles are provided with respect to the first and second components of a CMP polisher head, the rotation lock pins may each comprise a threaded portion and a non-threaded portion in some arrangements. In one implementation, the threaded portion may be configured to fasten into a wall portion of one of the rotational components of the polisher head (e.g., the first rotational component or the second rotational component) and the non-threaded portion of the rotation lock pin may have a form factor configured to engage with a corresponding one of the restrictor receptacles provided with the other rotational component (e.g., the second rotational component or the first rotational component) of the polisher head.

[0033] Additional details with respect to the foregoing examples will be set forth immediately below with particular reference to representative examples depicted in FIGS. 3-6.

[0034] FIG. 3 depicts a CMP tool 300 illustrating a partial cutaway side view of an example polisher head 301 according to some examples of the present disclosure. Example polisher head 301 includes an inner body 302 having a rolling seal 310 affixed proximate to a bottom terminus 322 of inner body 302, and an outer body 304 attached to inner body 302 in a rotational union facilitated by rolling seal 310. A circular flange 305 may be provided proximate to a top terminus 321 of inner body 302 for facilitating mechanical coupling with a shaft or spindle driven by a motor (e.g., a servo motor, not shown in this FIG.) around a first rotational axis, e.g., axis 306, in clockwise and/or counterclockwise directions as illustrated by a first rotational direction 308. Inner body 302 may have an outer wall 303 that may be contoured to have a variety of structural features (e.g., concentric annular steps, platforms, lips, grooves, etc.) generally conformal to an inner wall 323 of outer body 304 of polisher head 301 for engaging therewith as will be set forth further below. In some arrangements, a retainer ring 340 having an annular form factor may be mechanically coupled to a bottom portion 320 of outer body 304 using any type of fasteners, e.g., without limitation, nuts and bolts, screws, nails, rivets, anchors, pins, etc. A membrane 342 (e.g., porous or semi-porous membrane) may be disposed across retainer ring 340, wherein membrane 342 is configured to interface with a semiconductor process wafer 350 during a CMP operation. In some examples, CMP tool 300 may include a vacuum system (not shown) coupled to polisher head 301 for effectuating zonal control of membrane 342 by way of tubing facilitated by one or more apertures 309 formed in inner body 302. For example, membrane 342 may be configured to pick up and hold wafer 350 using vacuum suction applied onto a backside surface of wafer 350. In some examples, semiconductor process wafer 350 may be a semiconductor wafer comprising, for example, a semiconductor substrate (e.g., comprising silicon, a III-V semiconductor material, or the like), active devices (e.g., transistors, or the like) on the semiconductor substrate, and/or various interconnect structures. Representative interconnect structures may include conductive features, which electrically connect active devices in order to form functional circuits. In examples, CMP processing may be applied to semiconductor process wafer 350 during any stage of fabrication in order to planarize or otherwise remove features (e.g., dielectric material, semiconductor material, conductive material, or the like) from a top surface 354 of semiconductor process wafer 350, which is disposed in a face-down orientation for polishing.

[0035] CMP tool 300 includes a platen 360 having a polishing pad 362 disposed thereon may be coupled to a chuck 364 that is driven by a motor (e.g., an induction motor, not shown in this FIG.) around a second rotational axis, e.g., axis 366, in clockwise and/or counterclockwise directions as illustrated by a second rotational direction 368. Although not explicitly shown in FIG. 3, platen/pad arrangement 360/362 is generally larger than polisher head 301 containing semiconductor process wafer 350 (e.g., larger than the diameter of OBRR subassembly 304/340) regardless of whether a rotational CMP configuration (e.g., the polishing pad is rotated around an axis on a platen) or a linear CMP configuration (e.g., the polishing pad is moved linearly on a track) is implemented.

[0036] In some arrangements, inner wall 323 of outer body 304 may structural features such as, e.g., grooves, lips, steps, recesses, etc., exemplified by structural features 324 that may be dimensioned to facilitate a compressive fit arrangement with rolling seal 310 of inner body 302. For example, an interference fit, also known as press fit or friction fit, may be facilitated between structural features 324 and rolling seal 310 as a form of fastening the two components (e.g., inner and outer bodies 302, 304) in a mechanical joint that may be held together by friction, pressure, compression, and/or other tribological conditions that may be generated after the components are pushed or otherwise brought together. As previously noted, such an attachment may be implemented in polisher head 301 to effectuate a rotational union of inner and outer bodies 302, 304, thereby facilitating the transfer of rotational forces therebetween.

[0037] In the example arrangement of FIG. 3, a plurality of rotation lock pins 329 are attached to inner wall 323 of outer body 304, each of which is configured to engage with a corresponding restrictor receptacle provided as a slot, groove, channel, recess or similar structure disposed on outer wall 303 of inner body 302. By way of illustration, reference numeral 312 exemplifies such receptacles in the example shown in FIG. 3. In one arrangement, the plurality of rotation lock pins 329 may each comprise a coupling portion and an arresting portion, the coupling portion configured to fasten into or otherwise attached to inner wall 323 of outer body 304 and the arresting portion having a form factor configured to engage with a corresponding receptacle structure of inner body 302. For example, the coupling portion of a rotation lock pin may comprise a threaded portion whereas the arresting portion of a rotation lock pin may comprise a non-threaded portion in some examples. In some examples, the rotation lock pins may be attached to the inner wall of the outer body using a press-fit or interference fit type coupling mechanism. In some examples, the rotation lock pins may be integrally formed with the outer body in a unitary construction process as a single structure wherein the arresting portions are disposed as projections extending away from the inner wall of the outer body.

[0038] In one arrangement, the plurality of rotation lock pins 329 each comprise a coupling portion 332 and an arresting portion 334, exemplified as a threaded portion and a non-threaded portion, respectively, in FIG. 3, without limitation. As illustrated, the threaded coupling portion 332 may be configured to provide a fastening attachment into inner wall 323 and the non-threaded arresting portion 334 is provided with a form factor configured to engage with a corresponding receptacle 312 disposed in inner body 302.

[0039] Accordingly, after assembly of polisher head 301, rotation lock pins 329 are in a mechanical engagement with respective restrictor receptacles 312, regardless of how they are provided with respect to outer body 304, such that the arresting portions of rotation lock pins 329 operate to limit, arrest or otherwise restrict any rotational difference encountered between two rotational components, e.g., inner body 302 and outer body 304, thereby counteracting and/or preventing any over-rotation that may be experienced during a polishing operation of wafer 350 including, e.g., any wafer dechuck operations.

[0040] In one example implementation, polisher head 301 may be driven by a servo motor configured to provide a continuous torque of about 30-65 Newton-meters (Nm), with rotational speeds of up to 300 rpm and a peak torque rating of about 130 Nm. Whereas a baseline CMP operation may have an operating range of 35 Nm to 55 Nm, over-rotation-caused spikes in the range of peak torque ratings can occur during some wafer dechuck sequences depending on the process flows and consumable conditions as discussed.

[0041] Skilled artisans will recognize that the number of rotation lock pins and corresponding receptacles, respective form factors, as well as their placement/positioning on inner and/or outer bodies of a polisher head may vary depending on the implementation and application of a CMP tool according to the teachings herein. In an example arrangement, rotation lock pins 329 may be symmetrically positioned along a circular perimeter of inner wall 323 of outer body 304 or a portion thereof, with corresponding receptacles 312 likewise symmetrically positioned along a circular perimeter disposed or defined at a corresponding location on outer wall 303 of inner body 302 or a portion thereof. In an example arrangement, the plurality of slots or receptacles 312 may each comprise a recess having a cross-sectional area with two opposing sidewalls, wherein the cross-sectional area is dimensioned to accept arresting portion 334 of a corresponding rotation lock pin 329. In one arrangement, one or both of the two opposing sidewalls of a slot may comprise a vertical wall. In such an arrangement, when a rotator pin is forced against a vertical sidewall of the receptacle (depending on the directionality of a rotational torque due to over-rotation), it comes to a “hard” stop, thereby abruptly arresting the over-rotation. In another arrangement, at least one of the two opposing sidewalls of a slot receptacle may comprise a sloped wall (e.g., with an angle φ relative to a vertical plane), whereby when the rotator pin is urged against the sloped side, a vertical component of the arresting force is operative to provide a “lift”, which may assist in dechucking the wafer off the polishing pad. Depending on implementation, the receptacle sidewalls may also comprise curved or curvilinear walls having variable slopes along the respective curvatures in some examples.

[0042] FIGS. 4A and 4B depict example polisher head over-rotation restrictor configurations in a top down view of a polisher head according to some examples of the present disclosure. Polisher head 400A shown in FIG. 4A illustrates a 4-pin configuration wherein pins 408-1 to 408-4 are screwed into an outer body 404 of polisher head 400A, as illustrated by portions 410-1 to 410-4. Exposed portions of pins 408-1 to 408-4 are engaged in corresponding receptacles provided in an inner body 402 of polisher head 400A that is attached to outer body 404 via a rolling seal 403 for effectuating a rotational union around a common rotational axis 406. Directions of a polishing torque 420 and counterbalancing pin torque 422 are illustrated in FIG. 4A to indicate that a force from the pad to the polishing head (i.e., the polishing torque) is going in one direction whereas a force from the pins to the inner body (i.e., the pin torque) is going in the opposite direction.

[0043] Example polisher head 400B shown in FIG. 4B illustrates a 2-pin configuration wherein pins 458-1 and 458-2 are provided with an inner body 452 having a rotational axis 450 whereas corresponding restrictor receptacles 456-1 and 456-2 are disposed in an outer body 454 coupled therewith via a rolling seal 453. Polishing torque 462 and counter-balancing pin torque 464 are illustrative of forces caused in the over-rotation restriction process of the example configuration. Skilled artisans will recognize that the opposing rotational forces or torques exemplified in illustrative configurations can be clockwise and counterclockwise directions, or vice versa, regardless of the rotational directions of the polisher head and/or platen/pad arrangements in a CMP tool provided according to some examples herein.

[0044] FIG. 5 depicts example rotator lock pins for purposes of some examples of the present disclosure. Rotator lock pin 500A comprises a coupling portion, e.g., a threaded portion, 504A, and an arresting portion, e.g., a non-threaded portion, 502A that has a circular cross-sectional area. Rotator lock pin 500B likewise exemplifies a coupling portion, e.g., threaded portion 504B, and an arresting portion, e.g., non-threaded portion, 502B having a hexagonal cross-sectional area. Rotator lock pin 500C exemplifies a coupling portion, e.g., threaded portion, 504C, and an arresting portion, e.g., non-threaded portion, 502C, having a square cross-sectional area. In each of the foregoing examples, the respective lengths of coupling and arresting portions (e.g., threaded and non-threaded portions, respectively) as well as the total length of the rotator lock pins may be variable depending on the form factors of inner and outer bodies of a polisher head. It should be understood that other form factors for rotator lock pins are within the scope of the examples of the present disclosure.

[0045] FIG. 6 depicts cross-sectional views of example restrictor receptacle configurations operative to receive rotator lock pins of suitable form factors for purposes of some examples of the present disclosure. Configuration 600A is illustrative of a receptacle 602A having two vertical sidewalls formed in a polisher head body portion 604A, which may be an inner body portion or an outer body portion. In similar fashion, configurations 600B-600E illustrate different receptacles 602B-602E formed in either of polisher head body portions 604B-604E. Receptacle 602B is exemplified with a curvilinear wall arrangement having a semi-circular or other arcuate cross-sectional area profile. Receptacle 602C is exemplified with a single sloped wall having an angle φ with respect to a vertical plane 606, whereas the opposing sidewall is a vertical wall. Receptacle 602D is illustrative of an arrangement where both sidewalls may be provided as sloped walls, each exemplified with a respective angle with respect to corresponding vertical planes 608, 610, which may be the same (symmetrical sloping) or different (asymmetrical sloping). Receptacle 602E is illustrative of yet another arrangement wherein a notch or V-shaped profile may be provided for accepting a rotator lock pin having a suitable form factor as part of an over-rotation restriction mechanism implemented according to some examples of the present disclosure.

[0046] Although various implementations have been shown and described in detail, the claims are not limited to any particular implementation or example. None of the above Detailed Description should be read as implying that any particular component, element, step, act, or function is essential such that it must be included in the scope of the claims. Where the phrases such as “at least one of A and B” or phrases of similar import are recited or described, such a phrase should be understood to mean “only A, only B, or both A and B.” Reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described implementations that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims.

[0047] It should further be understood that the order or sequence of the acts, steps, functions, components or blocks illustrated in any of the flowcharts and/or block diagrams depicted in the drawing Figures of the present disclosure may be modified, altered, replaced, customized or otherwise rearranged within a particular flowchart/block diagram, including deletion or omission of a particular act, step, function, component or block. Moreover, the acts, steps, functions, components or blocks illustrated in a particular flowchart may be inter-mixed or otherwise inter-arranged or rearranged with the acts, steps, functions, components or blocks illustrated in another flowchart in order to effectuate additional variations, modifications and configurations with respect to one or more processes for purposes of the present disclosure. Accordingly, those skilled in the art will recognize that the example implementations described herein can be practiced with various modifications and alterations within the spirit and scope of the claims appended below.