CONTROLLED PROFILE POLISHING PLATEN

- Applied Materials, Inc.

Chemical-mechanical polishing assemblies may include an upper platen characterized by a first surface and a second surface opposite the first surface. The upper platen may define a recess in the second surface of the upper platen. The upper platen may define a flexure between the first surface and the second surface within the recess. The assemblies may include a polishing pad coupled with the first surface of the upper platen. The assemblies may include a plate coupled with the upper platen along the second surface of the upper platen. The plate may define a volume within the recess of the upper platen between the second surface of the upper platen and the plate.

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Description
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority to U.S. Provisional Application Ser. No. 63/166,692, filed Mar. 26, 2021, which is hereby incorporated by reference in its entirety for all purposes.

TECHNICAL FIELD

The present technology relates to semiconductor systems, processes, and equipment. More specifically, the present technology relates to components incorporated in chemical-mechanical polishing systems.

BACKGROUND

Chemical-mechanical polishing is commonly used in semiconductor processing to planarize or polish layers of material formed over a semiconductor substrate. In typical processing, a substrate is pressed against a rotating polishing pad on which a polishing slurry is flowed. Material formed along the substrate is removed through a combination of chemical interaction of the polishing slurry and mechanical interaction with the polishing pad. As processes increase in complexity, and non-uniformity of material formation on a substrate increases, standard chemical-mechanical polishing systems may be incapable of adequately responding to material structures to be polished.

Thus, there is a need for improved systems and methods that can be used to improve systems for increased polishing and removal precision. These and other needs are addressed by the present technology.

SUMMARY

Chemical-mechanical polishing assemblies may include an upper platen characterized by a first surface and a second surface opposite the first surface. The upper platen may define a recess in the second surface of the upper platen. The upper platen may define a flexure between the first surface and the second surface within the recess. The assemblies may include a polishing pad coupled with the first surface of the upper platen. The assemblies may include a plate coupled with the upper platen along the second surface of the upper platen. The plate may define a volume within the recess of the upper platen between the second surface of the upper platen and the plate.

In some embodiments, the recess defined within the second surface of the upper platen may be an annular recess defined about the upper platen. The recess defined within the second surface of the upper platen may be a stepped recess. The plate may be coupled with the upper platen along a recessed ledge within the stepped recess. The volume defined within the recess of the upper platen may be sealed with an elastomeric element disposed between the plate and the second surface of the upper platen. One or more stops may extend from the plate towards the flexure of the upper platen. The one or more stops may define a maximum deflection distance for the flexure defined by the upper platen. The one or more stops may include a plurality of stops. A first stop of the plurality of stops may be characterized by a height different from a second stop of the plurality of stops. The assemblies may include a pneumatic pump fluidly coupled with the volume within the recess of the upper platen. A fluid line from the pneumatic pump may couple with the plate. The assemblies may include a compliant wall extending from the plate to the second surface of the upper platen within the recess. The compliant wall may divide the volume within the recess of the upper platen into a first zone and a second zone. The first zone may be fluidly isolated from the second zone. The pneumatic pump may include a first fluid line extending to the first zone and a second fluid line extending to the second zone. The pneumatic pump may be operable to independently pump or purge each of the first zone and the second zone. The flexure may be characterized by a varying cross-sectional thickness across the flexure.

Some embodiments of the present technology may encompass polishing assemblies. The assemblies may include an upper platen characterized by a first surface and a second surface opposite the first surface. The upper platen may define a recess in the second surface of the upper platen. The upper platen may be characterized by a first cross-sectional thickness external to the recess. The upper platen may be characterized by a second cross-sectional thickness along a portion defining the recess. The assemblies may include a polishing pad coupled with the first surface of the upper platen. The assemblies may include a plate coupled with the upper platen along the second surface of the upper platen. The plate may define a volume within the recess of the upper platen between the second surface of the upper platen and the plate.

In some embodiments, the second cross-sectional thickness may be characterized by a thickness of less than or about 15 mm. A portion of the upper platen characterized by the second cross-sectional thickness of the upper platen may be located across a central axis of the upper platen. One or more protrusions may extend from the plate towards the upper platen. Each protrusion of the one or more protrusions may be characterized by an annular shape about the plate. The assemblies may include a pneumatic pump fluidly coupled with the volume within the recess of the upper platen. A fluid line from the pneumatic pump may couple with the plate. The assemblies may include a bellows extending from the plate to the second surface of the upper platen through the volume. The bellows may divide the volume within the recess of the upper platen into a first zone and a second zone. The first zone may be fluidly isolated from the second zone. The pneumatic pump may include a first fluid line extending to the first zone and a second fluid line extending to the second zone. The pneumatic pump may be operable to independently pump into, or purge from, each of the first zone and the second zone.

Some embodiments of the present technology may encompass polishing assemblies. The assemblies may include an upper platen characterized by a first surface and a second surface opposite the first surface. The upper platen may define a recess in the second surface of the upper platen. The upper platen may define a flexure between the first surface and the second surface within the recess. The assemblies may include a polishing pad coupled with the first surface of the upper platen. The assemblies may include a plate coupled with the upper platen along the second surface of the upper platen. The plate may define a volume within the recess of the upper platen between the second surface of the upper platen and the plate. The assemblies may include a pneumatic pump fluidly coupled with the volume within the recess of the upper platen. A fluid line from the pneumatic pump may fluidly access the volume.

In some embodiments, the flexure may be characterized by a varying cross-sectional area across the flexure. The assemblies may include a compliant wall extending from the plate to the second surface of the upper platen through the volume. The compliant wall may divide the volume within the recess of the upper platen into a first zone and a second zone. The first zone may be fluidly isolated from the second zone. The pneumatic pump may include a first fluid line extending to the first zone and a second fluid line extending to the second zone. the pneumatic pump may be operable to independently pump into, or purge from, each of the first zone and the second zone. One or more protrusions may extend from the plate towards the upper platen. The one or more protrusions may define a maximum inward deflection distance of the flexure.

Such technology may provide numerous benefits over conventional systems and techniques. For example, the platen flexures may allow improved conformance to materials exposed along a semiconductor substrate to be polished. Additionally, platen configurations according to the present technology may afford unique contact applications across a substrate surface, instead of affecting a location limited to a specific radial position. These and other embodiments, along with many of their advantages and features, are described in more detail in conjunction with the below description and attached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 shows a schematic cross-sectional view of an exemplary processing system according to some embodiments of the present technology.

FIGS. 2A-2B show schematic partial cross-sectional views of exemplary polishing assemblies according to some embodiments of the present technology.

FIG. 3 shows a schematic partial cross-sectional view of an exemplary polishing assembly according to some embodiments of the present technology.

FIG. 4 shows a schematic partial cross-sectional view of an exemplary polishing assembly according to some embodiments of the present technology.

FIGS. 5A-5B show schematic partial cross-sectional views of exemplary polishing assemblies according to some embodiments of the present technology.

FIG. 6 shows selected operations in a method of semiconductor processing according to some embodiments of the present technology.

Several of the figures are included as schematics. It is to be understood that the figures are for illustrative purposes, and are not to be considered of scale unless specifically stated to be of scale. Additionally, as schematics, the figures are provided to aid comprehension and may not include all aspects or information compared to realistic representations, and may include exaggerated material for illustrative purposes.

In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the letter.

DETAILED DESCRIPTION

Chemical-mechanical polishing often includes a multi-component system including a polishing assembly and a carrier head. A semiconductor substrate may be clamped into the carrier head, inverted, and depressed against a polishing pad on the polishing assembly. When non-uniform features or multiple films characterized by different physical properties are being removed, some systems may be able to modulate the pressure at which different zones of the substrate contact the polishing pad. For example, the carrier head may include chambers in which a pressure may be adjusted to increase or decrease a pressure applied to the substrate in that region. Similarly, a retaining ring extending outside of the substrate can be pressed with increased or decreased pressure to impact an overall effect on the substrate.

While these systems may provide a great degree of tuning to polishing operations, the systems may be limited in terms of certain fine-tune adjustments. For example, while a pressure may be applied to zones on the backside of the substrate, the chambers in the carrier head may often be circular or annular, and may only affect a specific radial zone about the substrate. Additionally, adjusting pressure on the backside of the substrate may afford less minute adjustments on polishing based on the need for the force to be applied through the thickness of the substrate.

The present technology overcomes these issues with conventional polishing systems by providing an adjustable surface on a polishing platen. Allowing a shape of the polishing platen to be modified may afford improved accommodations directly to the front side of the substrate being processed, and where the material to be removed is located. Additionally, by including different zones of accommodation in the platen according to some embodiments of the present technology, patterns of polishing can be produced that are not limited to specific radial zones of the substrate. Because the substrate may be rotated about a separate axis from which the platen may be rotated, adjustments along the platen surface may impact unique and more complex patterns on the substrate.

Although the remaining disclosure will routinely identify specific polishing processes utilizing the disclosed technology, it will be readily understood that the systems and methods are equally applicable to a variety of other chemical-mechanical polishing processes and systems. Accordingly, the technology should not be considered to be so limited as for use with the described polishing systems or processes alone. The disclosure will discuss one possible system that can be used with the present technology before describing systems and methods or operations of exemplary process sequences according to some embodiments of the present technology. It is to be understood that the technology is not limited to the equipment described, and processes discussed may be performed in any number of processing chambers and systems, along with any number of modifications, some of which will be noted below.

FIG. 1 shows a schematic cross-sectional view of an exemplary polishing system 100 according to some embodiments of the present technology. Polishing system 100 includes a platen assembly 102, which includes a lower platen 104 and an upper platen 106. Lower platen 104 may define an interior volume or cavity through which connections can be made, as well as in which may be included end-point detection equipment or other sensors or devices, such as eddy current sensors, optical sensors, or other components for monitoring polishing operations or components. For example, and as described further below, fluid couplings may be formed with lines extending through the lower platen 104, and which may access upper platen 106 through a backside of the upper platen. Platen assembly 102 may include a polishing pad 110 mounted on a first surface of the upper platen. A substrate carrier 108, or carrier head, may be disposed above the polishing pad 110 and may face the polishing pad 110. The platen assembly 102 may be rotatable about an axis A, while the substrate carrier 108 may be rotatable about an axis B. The substrate carrier may also be configured to sweep back and forth from an inner radius to an outer radius along the platen assembly, which may, in part, reduce uneven wear of the surface of the polishing pad 110. The polishing system 100 may also include a fluid delivery arm 118 positioned above the polishing pad 110, and which may be used to deliver polishing fluids, such as a polishing slurry, onto the polishing pad 110. Additionally, a pad conditioning assembly 120 may be disposed above the polishing pad 110, and may face the polishing pad 110.

In some embodiments of performing a chemical-mechanical polishing process, the rotating and/or sweeping substrate carrier 108 may exert a downforce against a substrate 112, which is shown in phantom and may be disposed within or coupled with the substrate carrier. The downward force applied may depress a material surface of the substrate 112 against the polishing pad 110 as the polishing pad 110 rotates about a central axis of the platen assembly. The interaction of the substrate 112 against the polishing pad 110 may occur in the presence of one or more polishing fluids delivered by the fluid delivery arm 118. A typical polishing fluid may include a slurry formed of an aqueous solution in which abrasive particles may be suspended. Often, the polishing fluid contains a pH adjuster and other chemically active components, such as an oxidizing agent, which may enable chemical mechanical polishing of the material surface of the substrate 112.

The pad conditioning assembly 120 may be operated to apply a fixed abrasive conditioning disk 122 against the surface of the polishing pad 110, which may be rotated as previously noted. The conditioning disk may be operated against the pad prior to, subsequent, or during polishing of the substrate 112. Conditioning the polishing pad 110 with the conditioning disk 122 may maintain the polishing pad 110 in a desired condition by abrading, rejuvenating, and removing polish byproducts and other debris from the polishing surface of the polishing pad 110. Upper platen 106 may be disposed on a mounting surface of the lower platen 104, and may be coupled with the lower platen 104 using a plurality of fasteners 138, such as extending through an annular flange shaped portion of the lower platen 104.

The polishing platen assembly 102, and thus the upper platen 106, may be suitably sized for any desired polishing system, and may be sized for a substrate of any diameter, including 200 mm, 300 mm, 450 mm, or greater. For example, a polishing platen assembly configured to polish 300 mm diameter substrates, may be characterized by a diameter of more than about 300 mm, such as between about 500 mm and about 1000 mm, or more than about 500 mm. The platen may be adjusted in diameter to accommodate substrates characterized by a larger or smaller diameter, or for a polishing platen 106 sized for concurrent polishing of multiple substrates. The upper platen 106 may be characterized by a thickness of between about 20 mm and about 150 mm, and may be characterized by a thickness of less than or about 100 mm, such as less than or about 80 mm, less than or about 60 mm, less than or about 40 mm, or less. In some embodiments, a ratio of a diameter to a thickness of the polishing platen 106 may be greater than or about 3:1, greater than or about 5:1, greater than or about 10:1, greater than or about 15:1, greater than or about 20:1, greater than or about 25:1, greater than or about 30:1, greater than or about 40:1, greater than or about 50:1, or more.

The upper platen and/or the lower platen may be formed of a suitably rigid, light-weight, and polishing fluid corrosion-resistant material, such as aluminum, an aluminum alloy, or stainless steel, although any number of materials may be used. Polishing pad 110 may be formed of any number of materials, including polymeric materials, such as polyurethane, a polycarbonate, fluoropolymers, polytetrafluoroethylene polyphenylene sulfide, or combinations of any of these or other materials. Additional materials may be or include open or closed cell foamed polymers, elastomers, felt, impregnated felt, plastics, or any other materials that may be compatible with the processing chemistries. It is to be understood that polishing system 100 is included to provide suitable reference to components discussed below, which may be incorporated in system 100, although the description of polishing system 100 is not intended to limit the present technology in any way, as embodiments of the present technology may be incorporated in any number of polishing systems that may benefit from the components and/or capabilities as described further below.

FIG. 2A shows a schematic partial cross-sectional view of an exemplary polishing assembly 200 according to some embodiments of the present technology. For example, polishing assembly 200 may illustrate further details regarding a portion of platen assembly 102 described above, and may include any component, feature, or characteristic of that assembly or polishing system 100, as well as any other polishing system with which polishing assembly 200 may be incorporated. It is to be understood that polishing assembly 200 is not illustrated to any particular scale, and is included merely to illustrate aspects of the present technology.

As illustrated, polishing assembly 200 may include an upper platen 205, which may be characterized by a first surface 207 and a second surface 209 opposite the first surface. Polishing assembly 200 may be incorporated in a polishing system where upper plate 205 may be coupled with a lower platen, such as lower platen 104 described above, along second surface 209, such as along an exterior region of the second surface of upper platen 205 as described previously. In some embodiments, upper platen 205 may define a recess 210 within the second surface 209 of upper platen 205. The recess may be formed in a region of the upper platen characterized by a reduced thickness as illustrated. For example, upper platen 205 may be characterized by a first cross-sectional thickness at one or more locations external and/or internal to recess 210, such as any of the thicknesses as discussed previously with regard to upper platen 106. Additionally, upper platen 205 may be characterized by a second cross-sectional thickness along a portion of upper platen 205 defining recess 210, and which may be less than the first cross-sectional thickness.

For example, the second cross-sectional thickness, which may be or include a number of thicknesses as discussed further below, may be less than or about 15 mm, and may be less than or about 12 mm, less than or about 10 mm, less than or about 9 mm, less than or about 8 mm, less than or about 7 mm, less than or about 6 mm, less than or about 5 mm, less than or about 4 mm, less than or about 3 mm, less than or about 2 mm, or less. Although an upper platen made of stainless steel may be characterized by reduced thicknesses as compared to aluminum, for example, in some embodiments the second cross-sectional thickness may be greater than or about 0.5 mm, greater than or about 1.0 mm, greater than or about 1.5 mm, or greater, which may ensure the section may maintain sufficient rigidity to withstand a downward force of a carrier head depressing a substrate against the platen as will be described further below.

By maintaining a reduced thickness across at least a portion of the upper platen 205 where the recess is defined, a flexure 215 may be formed within the upper platen between the first surface 207 and the second surface 209 along the recessed portion of the upper platen 205.

Polishing assembly 200 may include a polishing pad 220 as previously described, and which may be coupled with the upper platen 205 along the first surface 207 of the upper platen. During operation, a substrate 222, such as being held by a carrier head as previously described, may be depressed against the surface of the polishing pad opposite a surface coupled with the upper platen as shown. Additionally, polishing assembly 200 may include a plate 225 coupled with the upper platen along the second surface of the upper platen 205. Recess 210 may be or include a stepped recess as illustrated, and plate 225 may be coupled with the upper platen along a recessed ledge 227 within the stepped recess. The plate 225 and the upper platen 205 may define a volume 230 within the recessed portion of the upper platen. The volume 230 may be defined between the recessed portion of the upper platen and the plate 225, such as about a region including the flexure 215. Plate 225 may be sealingly coupled with the upper platen, such as by welding, bonding, or other coupling, or the plate may be removably coupled or fastened with the upper platen as illustrated. One or more elastomeric elements 232 may be disposed or seated between the plate 225 and the second surface of the upper platen 205, which may ensure a fluid seal during pressurized or vacuum operation as discussed below.

The flexure 215 may be operated in a passive configuration or an active configuration in some embodiments, and may adjust a profile of the upper platen 205 and polishing pad 220 during operation. During passive operation, a substrate being polished may be depressed against the polishing pad with an amount of force by the carrier head. This force may be applied to compress the flexure 215 downward in a sloped of concave manner, which may adjust the profile of the polishing pad as it impacts material on the surface of the substrate. The amount of deflection of the flexure 215 may be controlled by the downward pressure applied by the carrier head. Because the localized force applied against the flexure may be limited to an area about the carrier head, a unique contact application may be produced at the leading and trailing edges of the flexure as the platen rotates and the flexure begins to depress at a leading edge and reverts to a more planar arrangement from the trailing edge.

Additionally, the flexure 215 may be operated in an active manner with additional components of the polishing assembly. For example, and as illustrated in FIG. 2A, a pneumatic pump 235 may be coupled with the volume 230 formed adjacent the flexure 215. A fluid line 237 or port may be fitted or seated or otherwise coupled within the plate 225, and may provide fluid access to the volume 230. The pneumatic pump 235 may draw a vacuum within the volume 230, and which may produce a concave profile along the flexure, and which may be controlled more readily than with a downward force of a carrier head. Additionally, pneumatic pump 235 may be operated to increase pressure within the volume by delivering air or some fluid from a fluid source 239 into volume 230, and which may produce a convex profile along the flexure 215. To limit an amount of deflection of the flexure during passive or active operation, one or more stops or protrusions 240 may extend from the plate 225 within the volume and towards the upper platen 205. The protrusions may be sized to define a maximum deflection distance for the flexure. The protrusions may be characterized by an annular shape, and may extend in rings about the plate 225 as illustrated, and may be of any size or shape as will be discussed further below. The protrusions may be part of plate 225 in some embodiments, or may be coupled with or adhered with the plate.

As illustrated in FIG. 2A, in some embodiments recess 210, as well as volume 230 and plate 225, may be characterized by an annular shape about a central axis 245 of the polishing assembly 200. The recess may be formed to any radial length, and may be greater than or less than a diameter of a substrate to be processed. For example, the recess may be characterized by a radial length greater than or about 10% of a diameter of a substrate being processed, and may be characterized by a radial length greater than or about 25% of a diameter of a substrate being processed, greater than or about 50% of a diameter of a substrate being processed, greater than or about 75% of a diameter of a substrate being processed, greater than or about 90% of a diameter of a substrate being processed, greater than or about 100% of a diameter of a substrate being processed, greater than or about 110% of a diameter of a substrate being processed, greater than or about 120% of a diameter of a substrate being processed, or more.

Additionally, as illustrated in FIG. 2B, polishing assemblies according to some embodiments of the present technology may be characterized by a circular or oval-shaped volume. For example, polishing assembly 250 as illustrated, may show a variation of the polishing assembly 200 of FIG. 2A, and polishing assembly 250 may include any component, feature, or characteristic as described above. As illustrated, polishing assembly 250 includes similar features of polishing assembly 200, although recess 260 may extend across the central axis of upper platen 255 along a diameter less than an outer diameter of the upper platen 205. Accordingly, a flexure 265 formed along the upper platen, or a reduced second cross-sectional thickness of the platen, may be modified to produce a slope, concave profile, or convex profile across a central axis of the upper platen. Plate 270 may similarly be shaped as a round or oval component, which may be seated within or otherwise coupled with the upper platen 255 to produce a volume 275 as previously described. By utilizing oval, circular, or annular volumes, a number of variations may be provided according to embodiments of the present technology for polishing semiconductor substrates. Additionally, when the volume extends continuously across the central axis through the polishing assembly, the diameter of the volume may extend any of the percentages relative to a diameter of a substrate being polished as noted above, and may be double or triple any of the percentages noted.

Turning to FIG. 3 is shown a schematic partial cross-sectional view of an exemplary polishing assembly 300 according to some embodiments of the present technology. Polishing assembly 300 may show aspects of any polishing assembly previously described, and may illustrate additional features of polishing assemblies according to embodiments of the present technology. For example, polishing assembly 300 may show additional details of features of polishing system 100, or polishing assemblies 200 or 250 as discussed above, as well as may be included with any other feature or structure described in the present disclosure. Although polishing assembly 300 shows an annular-type volume formed in the assembly, it is to be understood that any aspect of polishing assembly 300 may be incorporated with any structure previously described, and polishing assembly 300 is not intended to limit the present technology to the specific configurations as shown.

Polishing assembly 300 may include any of the features discussed previously for any polishing assembly or system, and is shown in only a partial view to illustrate particular features of the structure. For example, polishing assembly 300 may include an upper platen 305, which may be characterized by a first surface 307 and a second surface 309 opposite the first surface. A recess 310 may be defined within second surface 309, which may define a flexure 315 as previously described. A polishing pad 320 may be coupled with first surface 307 of the polishing assembly, and a plate 325 may be coupled with the second surface 309 as discussed above. A volume 330 may be defined between the plate 325 and the recessed portion of the second surface of the upper platen as previously described. Similarly, a pneumatic pump 335 may be fluidly coupled with the volume with a fluid line 337 as discussed above, and which may access the volume through plate 325, such as with a port defined in the plate 325, for example.

As shown with polishing assembly 300, assemblies according to some embodiments of the present technology may include features to accommodate the flexure, including protrusions 340 or hard-stops, which may define an inward deflection distance of the flexure 315 as previously described. As shown, in some embodiments of the present technology, the protrusions may be shaped to adjust or control the deflection of the flexure. For example, in order to limit indentation, or to control a profile of the deflection, protrusions 340 may be characterized by any number of shapes or profiles. For example, protrusions 340a and 340c, which may extend outward of a center of the flexure, may be characterized by a first height. Additionally, protrusion 340b, which may be located axially in line with a maximum location of deflection, may be characterized by a second height different from the first height, such as lower than the first height. By including stops of different heights, stress on the flexure can be more evenly dispersed during deflection.

Additionally, in some embodiments any of the flexures may be characterized by sloped, curved, or beveled profiles as shown in protrusion 340a, and any or all protrusions may include rounded edges as illustrated with protrusion 340c. By adjusting an upper profile of the protrusions, and by limiting any sharp corners, for example, the flexure 315 may be protected and stress may be controlled during operation. Because the protrusions 340 may not be exposed to polishing slurries or other processing environment conditions, the protrusions may be formed of any number of materials, including a metal similar to the platen or the plate, as well as any polymeric, plastic, rubber, or other material, including combination materials, which may support and protect the flexure when in contact with the flexure.

Additionally, in some embodiments the interior volume 330 of the polishing assembly, including any polishing assembly discussed elsewhere, may include one or more dividers 345, which may provide multiple interior zones within the volume defined within the upper platen. Dividers may be or include a compliant material, which may be formed as a dividing wall extending from the plate 325 to the second surface 309 of the upper platen within the recess, such as coupling with a backside of the flexure 315 as illustrated. The dividers 345 may fluidly isolate adjacent interior zones within the volume, which may allow multiple effects to be applied in some embodiments of the present technology.

For example, in some embodiments, pneumatic pump 335 may include a first fluid line 337a extending to a first interior zone 350a, and a second fluid line 337b extending to a second interior zone 350b. Although only two such couplings are illustrated, it is to be understood that any number of interior zones and/or fluid couplings may be incorporated in polishing assemblies according to embodiments of the present technology, and which may include any number of dividers 345 to produce the zones. Because the divider 345b may fluidly isolate first interior zone 350a from second interior zone 350b, pneumatic pump 335 may independently pressurize and/or purge the two zones. Accordingly, the zones may be pressurized and/or purged to different degrees, or one or more zones may be pressurized, while one or more separate zones may be purged according to embodiments of the present technology. Consequently, configurations encompassed by the present technology, and depending on the number of independent zones incorporated, may be shaped to produce gradual slopes or curves, M-shaped, W-shaped, or other wave profiles. Consequently, a variety of unique polishing surfaces may be produced and applied against material to be polished on a semiconductor substrate.

Dividers 345 may be or include any number of materials or shapes, and may be or include any material previously described, including metals, polymers, rubbers, or other materials that may be coupled between the plate and the upper platen, and may withstand pressure or vacuum applied within the volume. The materials may be included in a number of ways, including a bellows configuration, such as shown with divider 345a, as well as a compressible or extendable compliant wall, as shown with divider 345b. Any number of other profiles may be used and may be adapted to an amount of deflection intended within any interior zone of the assembly.

FIG. 4 shows a schematic partial cross-sectional view of an exemplary polishing assembly according to some embodiments of the present technology. Polishing assembly 400 may show aspects of any polishing assembly previously described, and may illustrate additional features of polishing assemblies according to embodiments of the present technology. For example, polishing assembly 400 may describe additional details of features of polishing system 100, or polishing assemblies 200 or 250 as discussed above, as well as may be included with any other feature or structure described in the present disclosure. Similar to polishing assembly 300, although polishing assembly 400 shows an annular-type volume formed in the assembly, it is to be understood that any aspect of polishing assembly 400 may be incorporated with any structure previously described, and polishing assembly 400 is not intended to limit the present technology to the specific configurations as shown.

Polishing assembly 400 may include any of the features discussed previously for any polishing assembly or system, and is shown in only a partial view to illustrate particular features of the structure. For example, polishing assembly 400 may include an upper platen 405 during operation of the flexure 410, which may include any of the features or characteristics of any polishing assembly previously described. A vacuum may be applied to the volume as shown, which may draw the flexure towards the protrusions 415. Although the discussion is based on a vacuum being applied, the volume may also be pressurized to produce the opposite effect, and form a convex shape as illustrated in dashed lines 420.

In embodiments according to the present technology, the flexures may be characterized by a stiffness to provide controlled deformation based on pressurization or vacuum applied to an interior zone or the volume. For example, in some embodiments, the flexure 410, or any flexure described elsewhere, may be characterized by a stiffness of less than or about 0.10 mm/kPa, which may be an increasing stiffness, and may be characterized by a stiffness of less than or about 0.05 mm/kPa, less than or about 0.01 mm/kPa, less than or about 0.005 mm/kPa, less than or about 0.001 mm/kPa, or less. Additionally, the flexure may be formed, or the protrusion may be positioned and sized, to provide a maximum deflection available of less than or about 1.0 mm, and may provide a maximum deflection available of less than or about 0.75 mm, less than or about 0.70 mm, less than or about 0.65 mm, less than or about 0.60 mm, less than or about 0.55 mm, less than or about 0.50 mm, less than or about 0.45 mm, less than or about 0.40 mm, less than or about 0.35 mm, less than or about 0.30 mm, less than or about 0.25 mm, less than or about 0.20 mm, less than or about 0.15 mm, less than or about 0.10 mm, or less. Accordingly, by pressurizing or applying vacuum to a zone in a controlled manner, minute adjustments in the deflection of the flexure may be afforded in one or more zones within the volume.

FIGS. 5A-5B show schematic partial cross-sectional views of exemplary polishing assemblies according to some embodiments of the present technology, and may illustrate additional details of flexures according to embodiments of the present technology. Flexures as illustrated and discussed in relation to the figures may be incorporated in any polishing assembly discussed elsewhere, including any previously noted polishing assembly. As shown in the figures, in some embodiments, flexures may be characterized by a varying cross-sectional thickness across the flexure. For example, as shown in FIG. 5A, flexure 505 may be characterized by a tapered thickness across the flexure. Although shown extending in one direction, in embodiments the taper may extend in the opposite direction, or may extend towards the middle of the flexure before becoming thicker again. By adjusting the thickness of the flexure in one or more locations, or across a region of the flexure, deflection characteristics may be modified. For example, in the example illustrated in FIG. 5A, based on the taper, a location of maximum deflection may move from a center point of the flexure towards the tapered end. In embodiments one or more stops 510 may be adjusted to accommodate the offset deflection.

Additionally, as shown in FIG. 5B, flexure 520 may be characterized by a sloped shape towards a center of the flexure. The varying width may increase support at higher stress locations or coupling locations for the flexure. It is to be understood that the exemplary configurations illustrated in FIGS. 5A and 5B are intended only as examples, and any number of variations and modifications will be understood to be encompassed by the present technology. The variance within a flexure from a greatest cross-sectional thickness to a lowest cross-sectional thickness may be less than or about 5.0 mm, and may be less than or about 4.5 mm, less than or about 4.0 mm, less than or about 3.5 mm, less than or about 3.0 mm, less than or about 2.5 mm, less than or about 2.0 mm, less than or about 1.5 mm, less than or about 1.0 mm, less than or about 0.5 mm, or less, in embodiments according to the present technology.

Polishing assemblies explained above and according to embodiments of the present technology may be used in chemical-mechanical polishing operations. FIG. 6 shows selected operations in a method 600 of semiconductor processing according to some embodiments of the present technology. Method 600 may include one or more operations prior to the initiation of the stated method operations, including semiconductor processing to develop one or more layers of material on a substrate, and clamping a substrate to a carrier head of a polishing system as previously described. A polishing slurry may be applied to a polishing pad, and the carrier head may be positioned to depress the substrate against the polishing pad. In some embodiments, either before or during application of the carrier head against the polishing pad, a pressure or vacuum may be applied at operation 605 to a volume within an upper platen as previously described, and which may cause a flexure to deform against the pressure. The pressure may be adjusted in one or more interior zones of a volume, which may produce any variety of shapes of the flexure as previously described. The substrate may then be polished at operation 610 utilizing the specifically configured flexure configuration produced. In some embodiments, the pneumatic pump may not be used, and a flexure may passively be employed by deflection due to pressure by the carrier head and/or substrate. By utilizing flexures according to embodiments of the present technology, more complex polishing operations may be performed by utilizing an additional tuning mechanism for contacting the substrate to be polished.

In the preceding description, for the purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. It will be apparent to one skilled in the art, however, that certain embodiments may be practiced without some of these details, or with additional details.

Having disclosed several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the embodiments. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present technology. Accordingly, the above description should not be taken as limiting the scope of the technology.

Where a range of values is provided, it is understood that each intervening value, to the smallest fraction of the unit of the lower limit, unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Any narrower range between any stated values or unstated intervening values in a stated range and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of those smaller ranges may independently be included or excluded in the range, and each range where either, neither, or both limits are included in the smaller ranges is also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “a flexure” includes a plurality of such flexures, and reference to “the protrusion” includes reference to one or more protrusions and equivalents thereof known to those skilled in the art, and so forth.

Also, the words “comprise(s)”, “comprising”, “contain(s)”, “containing”, “include(s)”, and “including”, when used in this specification and in the following claims, are intended to specify the presence of stated features, integers, components, or operations, but they do not preclude the presence or addition of one or more other features, integers, components, operations, acts, or groups.

Claims

1. A polishing assembly comprising:

an upper platen characterized by a first surface and a second surface opposite the first surface, wherein the upper platen defines a recess in the second surface of the upper platen, and wherein the upper platen defines a flexure between the first surface and the second surface within the recess;
a polishing pad coupled with the first surface of the upper platen; and
a plate coupled with the upper platen along the second surface of the upper platen, and defining a volume within the recess of the upper platen between the second surface of the upper platen and the plate.

2. The polishing assembly of claim 1, wherein the recess defined within the second surface of the upper platen comprises an annular recess defined about the upper platen.

3. The polishing assembly of claim 1, wherein the recess defined within the second surface of the upper platen is a stepped recess, wherein the plate is coupled with the upper platen along a recessed ledge within the stepped recess, and wherein the volume defined within the recess of the upper platen is sealed with an elastomeric element disposed between the plate and the second surface of the upper platen.

4. The polishing assembly of claim 1, wherein one or more stops extend from the plate towards the flexure of the upper platen, and wherein the one or more stops define a maximum deflection distance for the flexure defined by the upper platen.

5. The polishing assembly of claim 4, wherein the one or more stops comprise a plurality of stops, and wherein a first stop of the plurality of stops is characterized by a height different from a second stop of the plurality of stops.

6. The polishing assembly of claim 1, further comprising:

a pneumatic pump fluidly coupled with the volume within the recess of the upper platen, wherein a fluid line from the pneumatic pump couples with the plate.

7. The polishing assembly of claim 6, further comprising:

a compliant wall extending from the plate to the second surface of the upper platen within the recess, wherein the compliant wall divides the volume within the recess of the upper platen into a first zone and a second zone, and wherein the first zone is fluidly isolated from the second zone.

8. The polishing assembly of claim 7, wherein the pneumatic pump comprises a first fluid line extending to the first zone and a second fluid line extending to the second zone, and wherein the pneumatic pump is operable to independently pump or purge each of the first zone and the second zone.

9. The polishing assembly of claim 1, wherein the flexure is characterized by a varying cross-sectional thickness across the flexure.

10. A polishing assembly comprising:

an upper platen characterized by a first surface and a second surface opposite the first surface, wherein the upper platen defines a recess in the second surface of the upper platen, wherein the upper platen is characterized by a first cross-sectional thickness external to the recess, and wherein the upper platen is characterized by a second cross-sectional thickness along a portion defining the recess;
a polishing pad coupled with the first surface of the upper platen; and
a plate coupled with the upper platen along the second surface of the upper platen, wherein the plate defines a volume within the recess of the upper platen between the second surface of the upper platen and the plate.

11. The polishing assembly of claim 10, wherein the second cross-sectional thickness is characterized by a thickness of less than or about 15 mm.

12. The polishing assembly of claim 10, wherein a portion of the upper platen characterized by the second cross-sectional thickness of the upper platen is located across a central axis of the upper platen.

13. The polishing assembly of claim 10, wherein one or more protrusions extend from the plate towards the upper platen, and wherein each protrusion of the one or more protrusions is characterized by an annular shape about the plate.

14. The polishing assembly of claim 10, further comprising:

a pneumatic pump fluidly coupled with the volume within the recess of the upper platen, wherein a fluid line from the pneumatic pump couples with the plate.

15. The polishing assembly of claim 14, further comprising:

a bellows extending from the plate to the second surface of the upper platen through the volume, wherein the bellows divides the volume within the recess of the upper platen into a first zone and a second zone, and wherein the first zone is fluidly isolated from the second zone.

16. The polishing assembly of claim 15, wherein the pneumatic pump comprises a first fluid line extending to the first zone and a second fluid line extending to the second zone, and wherein the pneumatic pump is operable to independently pump into, or purge from, each of the first zone and the second zone.

17. A polishing assembly comprising:

an upper platen characterized by a first surface and a second surface opposite the first surface, wherein the upper platen defines a recess in the second surface of the upper platen, and wherein the upper platen defines a flexure between the first surface and the second surface within the recess;
a polishing pad coupled with the first surface of the upper platen;
a plate coupled with the upper platen along the second surface of the upper platen, and defining a volume within the recess of the upper platen between the second surface of the upper platen and the plate; and
a pneumatic pump fluidly coupled with the volume within the recess of the upper platen, wherein a fluid line from the pneumatic pump fluidly accesses the volume.

18. The polishing assembly of claim 17, wherein the flexure is characterized by a varying cross-sectional area across the flexure.

19. The polishing assembly of claim 17, further comprising:

a compliant wall extending from the plate to the second surface of the upper platen through the volume, wherein the compliant wall divides the volume within the recess of the upper platen into a first zone and a second zone, wherein the first zone is fluidly isolated from the second zone, wherein the pneumatic pump comprises a first fluid line extending to the first zone and a second fluid line extending to the second zone, and wherein the pneumatic pump is operable to independently pump into, or purge from, each of the first zone and the second zone.

20. The polishing assembly of claim 17, wherein one or more protrusions extend from the plate towards the upper platen, and wherein the one or more protrusions define a maximum inward deflection distance of the flexure.

Patent History
Publication number: 20220305613
Type: Application
Filed: Feb 16, 2022
Publication Date: Sep 29, 2022
Applicant: Applied Materials, Inc. (Santa Clara, CA)
Inventors: Steven M. Zuniga (Soquel, CA), Bum Jick Kim (Irvine, CA), Jay Gurusamy (Santa Clara, CA)
Application Number: 17/673,511
Classifications
International Classification: B24B 37/26 (20060101);