WO2018118047A1

WO2018118047A1 - Conditioning disks to condition semiconductor wafer polishing pads

Info

Publication number: WO2018118047A1
Application number: PCT/US2016/068054
Authority: WO
Inventors: Alexander Tregub; Ken A. Delbridge
Original assignee: Intel Corp
Current assignee: Intel Corp
Priority date: 2016-12-21
Filing date: 2016-12-21
Publication date: 2018-06-28
Anticipated expiration: 2019-06-21

Abstract

Conditioning disks to condition semiconductor wafer polishing pads are disclosed. An example chemical mechanical planarization conditioning disk includes a substrate and a nodule projecting a first height from the substrate. The conditioning disk further includes a protective structure projecting from the substrate. The protective structure is adjacent the nodule. The protective structure has an upper surface at a second height relative to the baseline surface. An area of the upper surface of the protective structure is greater than a top surface of the nodule.

Description

CONDITIONING DISKS TO CONDITION

SEMICONDUCTOR WAFER POLISHING PADS

FIELD OF THE DISCLOSURE

[0001] This disclosure relates generally to semiconductor device fabrication, and, more particularly, to conditioning disks to condition semiconductor wafer polishing pads.

BACKGROUND

[0002] Semiconductor device manufacturing involves the formation and electrical interconnection of microelectronic devices on a semiconductor substrate. Some common example substrates include silicon wafers and gallium arsenide wafers. The degree of planarity of a semiconductor wafer can have a significant impact on the quality and/or performance of integrated circuits formed thereon. Accordingly, semiconductor wafers typically undergo a process of chemical mechanical planarization (also sometimes referred to as chemical mechanical polishing) to polish or smooth out the surface of the wafers prior to subsequent processing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 illustrates and example chemical mechanical planarization (CMP) apparatus with a conditioning disk constructed in accordance with the teachings disclosed herein.

[0004] FIG. 2 is a plan view of an example prominent surface feature on the example conditioning disk of FIG. 1.

[0005] FIG. 3 is a cross-sectional view of the example prominent surface feature of FIG. 2 taken along the line 3-3.

[0006] FIG. 4 shows the polishing pad of FIG. 1 pressed against the example prominent surface feature of FIGS. 1-3.

[0007] FIG. 5 is a plan view of another example prominent surface feature that may be implemented on the example conditioning disk of FIG. 1. [0008] FIG. 6 is a cross-sectional view of the example prominent surface feature of FIG. 5 taken along the line 6-6.

[0009] FIG. 7 is a cross-sectional view of another example prominent surface feature that may be implemented on the example conditioning disk of FIG. 1.

[0010] FIG. 8 shows cross-sectional views of three example nodules that may be implemented in connection with any of the example prominent surface features of FIG. 1-7.

[0011] FIG. 9 shows cross-sectional views of the three example nodules of FIG. 8 after the nodules have been worn down to approximately half their original height.

[0012] FIG. 10 is a graph illustrating the relationship between nodule height and disk aggressiveness derived from tested results.

[0013] FIG. 11 is a graph illustrating the relationship between nodule width and disk aggressiveness derived from tested results.

[0014] FIG. 12 is a graph illustrating the relationship between the number of nodules and disk aggressiveness derived from tested results.

[0015] FIG. 13 is a flowchart of an example method to manufacture any of the example prominent surface features of FIG. 1-7 on the example conditioning disk of FIG. 1.

DETAILED DESCRIPTION

[0016] Chemical mechanical planarization (CMP) is a known method of planarizing or polishing the surface of a layer of a substrate such as a semiconductor wafer. CMP combines chemical etching and mechanical abrasion to remove roughness on the surface of the wafer. More particularly, a surface of a wafer is moved against a polishing pad having a textured surface. A slurry is provided between the surface of the wafer and the polishing pad. The interaction between the wafer and the polishing pad, in conjunction with the slurry, results in the polishing of the facing surface of the wafer. The interaction between the wafer and the polishing pad also causes the polishing pad to become smoother, which reduces the effectiveness with which the pad may polish the wafer. Accordingly, during the CMP polishing process and/or between such polishing operations, the polishing pad is roughened by a conditioning disk with an abrasive surface to restore the textured surface of the polishing pad.

[0017] Important performance characteristics of a conditioning disk include the disk aggressiveness and the disk stability. Disk aggressiveness refers to the rate at which a disk is able to cut or otherwise roughen a polishing pad. Disk stability refers to the consistency of the disk aggressiveness over time. The abrasive surface of a many known conditioning disks wear down relatively quickly, thereby reducing the aggressiveness of the disk.

Furthermore, the ability of a conditioning disk to reliably roughen a polishing pad changes over time as the disk wears down such that there is relatively high process variability in the disk's use over an extended period of time. As a result of the loss of aggressiveness and the limited stability, conditioning disks are replaced relatively frequently. This high replacement frequency increases costs due to the need for replacement parts as well as the downtime experienced while such parts are being replaced.

[0018] Example CMP conditioning disks disclosed herein have a significantly longer useful life with better control of the performance characteristics (e.g., aggressiveness, stability, etc.) than other previously known conditioning disks. Example conditioning disks disclosed herein include one or more nodules with specifically designed geometries that protrude from baseline surface on a conditioning disk (e.g., the underlying surface at the base of the nodule that would be present if the nodule was absent). Such nodules have been found to increase both the aggressiveness (e.g., polishing pad cut rate) and stability (e.g., consistency of the

aggressiveness over time) of conditioning disks, thereby improving the effectiveness of such disks.

[0019] While a protruding nodule improves the aggressiveness and stability of a conditioning disk, the nodule, by its nature of protruding beyond other portions (e.g., all other portions) of the surface of the disk, is likely to wear down relatively fast. Accordingly, in some examples, the conditioning disk includes one or more protective structure(s) positioned adjacent to each nodule. The protective structure(s) protrude from the baseline surface of the conditioning disk. In some examples, a top surface of the protective structure (i.e., the surface furthest away from the baseline surface at the protruding end of the protective structure) has a larger area than the top surface of the nodule to distribute a load created by pressing the conditioning disk against the polishing pad. The distribution of load across the larger area (e.g., the combined area defined by the protruding end of the nodule and the protective structure(s)) reduces pressure on the nodule, thereby reducing the rate at which the nodule may be worn away. In this manner, the useful life of the conditioning disk can be substantially increased when compared to other known disks. In some examples, the nodule has a height (relative to the baseline surface) that is slightly greater than the height of the protective structure(s) to enable the nodule to provide a desired degree of aggressiveness. In some examples, the difference in height between the nodule and the protective structure approximately corresponds to a thickness of a hard film coating applied to the surface of the nodule. The coating may be applied to increase the wear resistance of the nodule.

[0020] FIG. 1 illustrates an example CMP apparatus 100 with a conditioning disk 102 constructed in accordance with the teachings disclosed herein. During a CMP process, as represented in FIG. 1, a semiconductor wafer 104 (or any other suitable substrate to be polished) is supported by a wafer carrier 106. In the illustrated example, the wafer 104 is inverted such that a normally top surface 108 (i.e., the surface on which microelectronic devices are formed) is facing downward toward a polishing pad 110. The polishing pad 110 is fixedly mounted to a platen 112 that is rotated about an axis 114. Although the wafer 104 and the polishing pad 110 are shown spaced apart in FIG. 1, during CMP operations, the top surface 108 of the wafer 104 is pressed against the polishing pad 110 to cause the rotating polishing pad 110 to polish the wafer 104. In some examples, the wafer carrier 106 rotates the wafer 104 about a second axis 116. Further, in some examples, a wafer support arm 118 may move (as represented by the arrow 120) in the plane of the surface of the polishing pad 110 to cause the wafer 104 to translate along the surface of the polishing pad 110 during the polishing operation.

[0021] As the platen 112 and polishing pad 110 rotate, a slurry dispenser 122 dispenses a slurry 124 onto the surface of the polishing pad 110. The slurry 124 may contain abrasive particles and/or chemical etchants to facilitate the polishing of the wafer 104. In particular, the surface roughness of the top surface 108 of the wafer 104 is substantially removed (e.g., reduced or even eliminated) by the combined action of the chemicals in the slurry 124 and the physical abrasion brought about by relative movement (e.g., rotational and/or translational) between the polishing pad 110 and the wafer 104.

[0022] As asperities or other portions of the wafer 104 are removed by the polishing pad 110, a combination of slurry and debris tends to clog pores in the surface of the polishing pad 110, such that over time, the polishing pad 110 becomes less effective. Accordingly, in the illustrated example, the surface of the polishing pad 110 is cleaned, repurposed, and/or conditioned by the conditioning disk 102 supported by a disk carrier 126. More particularly, the conditioning disk 102 is pressed against and moved relative to the polishing pad 110 to roughen up the surface of the polishing pad 110 and restore the desired surface texture and roughness of the pad 110. The relative movement between the polishing pad 110 and the conditioning disk 102 may result from rotation of the polishing pad 110 on the rotating platen 112.

Furthermore, in some examples, the disk carrier 126 rotates the conditioning disk 102 about a third axis 130 while a disk support arm 132 moves laterally (represented by arrow 134) to create additional modes of relative movement between the conditioning disk 102 and the polishing pad 110. In the examples of FIG. 1, the roughening of the polishing pad 110 occurs at the same time that the wafer 104 is polished. In other examples, the roughening and polishing may be done at different times and/or on different machines.

[0023] In the illustrated example of FIG. 1, the conditioning disk 102 includes at least one prominent surface feature 136 that protrudes from a baseline surface 128 of the conditioning disk 102. In the illustrated example, the baseline surface 128 corresponds to a surface of the disk 102 facing the polishing pad 1 10. In other examples, the baseline surface 128 may correspond to a pedestal or other intermediate component attached to conditioning disk 102. As shown in the illustrated example, the prominent surface feature 136 includes a nodule 138 and one or more protective structure(s) 140 adjacent to the nodule 138. In the illustrated example, the nodule 138 is the primary component to roughen or conditioning the polishing pad 1 10. That is, the nodule 138 is the primary contributing factor to the aggressiveness of the conditioning disk 102. In some examples, the protective structure(s) 140 serve to protect the nodule 138 to thereby increase its useful life by reducing the rate at which the nodule 138 wears down. The protective structure(s) 140 may have a height (relative to the baseline surface 128) that is either equal to or less than the nodule 138. That is, in some examples, the nodule 138 defines the maximum height of the prominent surface feature 136.

[0024] In some examples, the conditioning disk 102 includes only one prominent surface feature 136 (as shown in FIG. 1). In other examples, more than one prominent surface feature 136 may be included (e.g., 2, 3, 4, 5, 10, 15, 20, etc.). Unlike some known conditioning disks that include hundreds of micro-replicated surface features distributed across the surface 128 of the disk, in some examples disclosed herein, the total number of prominent surface features 136 may be relatively limited (e.g., less than 30). In examples where there are two or more prominent surface features 136, the height of each prominent surface feature 136 (and corresponding nodule 138) relative to the baseline surface 128 of the underlying substrate is substantially the same (e.g., within +/- 5 μιτι).

[0025] While tests have shown that a relatively limited number of nodule(s) 138 protruding beyond the rest of the surface 128 of the

conditioning disk 102 may improve the aggressiveness of the conditioning disk 102, absent corrective measures (e.g., the provision of protective structure(s)) the relatively high loads experienced by the nodule(s) 138 may result in the nodules 138 wearing down relatively quickly. Wearing down of the nodule(s) 138 can result in a reduction of aggressiveness and

corresponding loss of stability or consistency in the effectiveness of the conditioning disk 102. Accordingly, in examples disclosed herein, the protective structure(s) 140 are positioned adjacent to the nodule(s) 138 to reduce the rate at which the nodule(s) 138 wear down. In particular, the protective structure(s) 140 in the illustrated example serve to take some of the load from the polishing pad 110 to reduce the load experienced by the corresponding nodule(s) 138. In this manner, the nodule(s) 138 have been found to wear down much more slowly than in the absence of the protective structure(s) 140, thereby increasing the service life of the conditioning disk 102.

[0026] FIG. 2 is a plan view of the example prominent surface feature 136 on the example conditioning disk 102 of FIG. 1 while FIG. 3 is a cross- sectional view of the example prominent surface feature 136 taken along the line 3-3 of FIG. 2. As shown in the illustrated examples, the nodule 138 is a truncated pyramid with four sidewalls 202, 204, 206, 208 and a flat top surface 210. In some examples, the pyramid shape of the nodule 138 may not be truncated such that there is no flat top surface 210 because the four sidewalls 202, 204, 206, 208 converge to a central point. Further, while the example nodule 138 of FIGS. 2 and 3 is in the shape of a pyramid, the nodule 138 may have any other suitable shape (e.g., conical, cylindrical, polyhedral, etc.).

[0027] In the illustrated example of FIG. 2, the protective structure(s) 140 have a generally rectangular shape positioned adjacent the nodule 138 on either side (e.g., adjacent the sidewalls 204, 208 in FIG. 2). As a result, at least some sides (e.g., corresponding to the sidewalls 202, 206 in FIG. 2) of the nodule 138 are exposed or unprotected. In some examples, only one protective structure 140 is positioned adjacent the nodule 138 such that all other sides are exposed. In other examples, additional protective structure(s) 140 may be included at different locations to surround additional (e.g., all) sides of the nodule 138 (e.g., four protective structures with one adjacent each of the four sidewalls 202, 204, 206, 208). More generally, there may be any suitable number of protective structures 140 adjacent the nodule 138 positioned at any suitable location to surround some or all of the nodule 138. [0028] While FIG. 2 shows the protective structure(s) 140 as being generally rectangular in shape, the protective structure(s) 140 may be any other suitable shape. In some examples, the protective structure(s) 140 is L- shaped, U-shaped, or otherwise shaped to extend around multiple sides of the nodule. In some examples, regardless of the shape of the protective structure(s) 140 from an overhead view (as shown in FIG. 2), the protective structure(s) 140 have a generally rectangular cross-section (as shown in FIG. 3) with lateral walls 212 that are substantially perpendicular to a substantially flat upper surface 214 and substantially perpendicular to the baseline surface 128 of the conditioning disk 102. As a result, the upper surface 214 may be substantially parallel to the baseline surface 128 of the conditioning disk 102 and, thus, substantially parallel to the surface of the polishing pad 110 when in use. In this manner, when the conditioning disk 102 is pressed against the polishing pad 110, the polishing pad 110 is likely to engage with substantially the entire upper surface 214 of the protective structure(s) 140, thereby enabling the resulting load to be distributed across substantially the entire upper surface 214 of the protective structure(s) 140 and the top surface 210 of the nodule 138. In some examples, the cross-section of the protective structure(s) 140 may be in a shape other than a rectangle. For example, the lateral walls 212 may be at an angle relative to a direction normal to the baseline surface 128. In some examples, the lateral walls 212 may be curved or otherwise not straight. In some examples, the upper surface 214 may not be flat, for example, it may be concave, convex, etc.

[0029] As shown in the illustrated example of FIG. 2, the area of the upper surface 214 of the protective structure(s) 140 is significantly greater than the area of the top surface 210 of the nodule 138. In some examples, the area of the upper surface 214 of the protective structure(s) 140 is at least twice the area of the top surface 210 of the nodule 138. In some examples, the area of the upper surface 214 of the protective structure(s) 140 is at least five times the area of the top surface 210 of the nodule 138. In some examples, the area of the upper surface 214 of each protective structure 140 may be similar to the top surface 210 of the nodule 138 but a combined total area of all protective structures 140 adjacent the nodule 138 is greater than the top surface 210 of the nodule. As a result of the larger surface area, the protective structure(s) 140 may significantly reduce the load applied to the nodule 138 because the load is distributed over a larger area including the upper surface 214 of the protective structure(s) 140 and the top surface 210 of the nodule 138. In some examples, the nodule 138 may experience a greater load per unit area than the protective structure(s) 140 because the nodule 138 is taller than the protective structure(s) 140. However, testing has shown that the protective structure(s) 140 still significantly reduce the rate of wear of the nodule 138 when compared with a similar nodule 138 that does not have adjacent protective structure(s) 140.

[0030] Furthermore, as the nodule 138 begins to wear away such that the difference in height between the nodule 138 and the protective structure(s) 140 reduces, the ability of the protective structure(s) 140 to reduce the rate of wear of the nodule 138 increases. For example, FIG. 4 shows the polishing pad 1 10 of FIG. 1 pressed against the example prominent surface feature 136 of FIGS. 1 -3 after the nodule 138 has worn down to the same height as the protective structure(s) 140. The illustrated example of FIG. 4 is inverted relative to the illustrated example of FIG. 1. As shown in the illustrated example, once the nodule 138 has worn down to the height of the protective structure(s) 140, additional wear on the nodule 138 is significantly reduced because the polishing pad 110 interfaces with the upper surfaces 214 of the protective structure(s) 140 with the same force as the nodule 138. With the much larger area of the upper surfaces 214, the impact of the load on the nodule 138 is significantly reduced, thereby greatly reducing the rate at which the nodule 138 wears away.

[0031] In some examples, the protective structure(s) 140 are constructed with rounded edges 216 at the intersection of the lateral walls 212 and the upper surface 214. In some examples, the rounded edges 216 have a radius of at least 5 μιτι. The rounded edges 216 reduce the impact (and, thus, reduce the aggressiveness) of the protective structure(s) 140 on the polishing pad 1 10. That is, as shown in FIG. 4, when the polishing pad 110 is pressed against and moved (e.g., rotated and/or translated) relative to the conditioning disk 102, the rounded edges 216 reduce the ability of the protective structure(s) 140 to cut or otherwise roughen the surface of the polishing pad 110. As a result, the nodule 138 is the primary structure contributing to the aggressiveness of the conditioning disk 102. In some examples, the aggressiveness of the protective structure(s) 140 is negligible such that the nodule 138 is the only structure substantially contributing to the

aggressiveness of the disk 102. Accordingly, in some examples, the aggressiveness of the conditioning disk 102 can be precisely controlled based on the geometric design (e.g., shape, width, height, sidewall angle, etc.) of the nodule 138 as described more fully below

[0032] As mentioned above, the nodule 138 and the protective structure(s) 140 may be designed with any suitable shape, another example of which is shown in FIGS. 5 and 6. In particular, FIG. 5 is a plan view of another example prominent surface feature 502 that may be implemented on the conditioning disk 102 of FIG. 1. FIG. 6 is a cross-sectional view of the example prominent surface feature 502 taken along the line 6-6 of FIG. 5. In the illustrated example of FIGS. 5 and 6, the prominent surface feature 502 includes a nodule 504 that has a generally truncated conical shape with a round sidewall 506 and a flat top surface 508. In some examples, the nodule 504 may not be truncated such that there is no flat top surface 508 because the nodule 504 forms a completed cone with the sidewall 506 rising to a central point.

[0033] In the illustrated example of FIGS. 5 and 6, the prominent surface feature is implemented as a single protective structure 510 that entirely surrounds the nodule 504. Thus, in some examples, the protective structure 510 may partially or completely enclose the nodule 504 (e.g., within a plane of the baseline surface 128). As with the protective structure(s) 140 of FIGS. 1- 3, the example protective structure 510 of FIGS. 5 and 6 includes lateral walls 512 that are substantially perpendicular to a substantially flat upper surface 514 to form a generally rectangular cross-section. Further, a perimeter of the upper surface 514 of the example protective structure 510 (where the lateral walls 512 join the upper surface 514) exhibits rounded edges 516. As represented in the illustrated example of FIG. 5, the area of the upper surface 514 is significantly larger than the area of the top surface 508 of the nodule 504. The presence of the upper surface 514 reduces the load experienced by the nodule 504 because a significant portion of the load is distributed across a relatively larger area than the top surface 508 of the nodule 504 alone.

[0034] FIG. 7 is a cross-sectional view of another example prominent surface feature 700 that may be implemented on the conditioning disk 102 of FIG. 1. In the illustrated example, the prominent surface feature 700 includes a nodule 702 with one or more adjacent protective structure(s) 704. As shown in FIG. 7, the nodule 702 includes an inner structure 706 and a film 708 coating the inner structure 706. In some examples, the inner structure 706 is made of the same material as the protective structure(s) 704 and the underlying substrate (e.g., the conditioning disk 102). In some examples, the film 708 is a diamond film. In other examples, the film 708 may be formed of any other suitable material that increases the hardness (to increase wear resistance) and/or increases the chemical resistance of the nodule 702. In some examples, as shown in FIG. 7, the film 708 is specifically applied to some or all of the surface of inner structure 706 of the nodule 702 to the exclusion of the protective structure(s) 704 and the rest of the baseline surface 128 of the conditioning disk 102. In other examples, the protective structure(s) 704 and/or the baseline surface 128 may be completely or partially coated with the film 708. In some examples, a similar film may be applied to the illustrated examples of FIGS. 1-6.

[0035] In the illustrated example of FIG. 7, a difference between a height 710 of the protective structure(s) 704 and a height 712 of the nodule 702 (including the film 708) approximately equals a thickness 714 of the film 708. In other words, in some examples, the height 712 of the protective structure(s) 704 approximately equals the height of the underlying inner structure 706 of the nodule 702. Thus, the portion of the nodule 702 that protrudes beyond an upper surface 716 of the protective structure(s) 704 corresponds to the film 708. As a result, the film 708 may remain exposed on the top surface 718 of the nodule 702 approximately until the nodule 702 has worn away to the height of the protective structure(s) 704 in a similar manner to that shown in FIG. 4. In some examples, the difference between the height 710 of the protective structure(s) 704 and the height 712 of the nodule 702 is less than the thickness 714 of the film 708 such that at least a portion of the film 708 may remain on the top surface 718 of the nodule 702 even after the nodule 702 has been worn down to the height of the protective structure(s) 704. In some examples, the thickness 714 of the film 708 ranges from approximately 5 μιτι to 20 μιτι. In some examples, the film thickness 714 ranges from approximately 1 μιτι to 25 μιτι or greater. In some examples, the film thickness 714 may be as high as 50 μιτι.

[0036] FIG. 8 shows cross-sectional views of three example nodules 802, 804, 806 that may be used in connection with any of the example prominent surface features 136, 502, 700 of FIG. 1-7. The first example nodule 802 includes sidewalls 808 that have a relatively large angle relative to a direction normal to a baseline surface from which the nodule 802 projects. The second example nodule 804 includes sidewalls 812 that have a smaller angle relative to the first nodule 802. The third example nodule 806 includes sidewalls 816 that are substantially parallel to the normal direction (i.e., substantially vertical). In the illustrated examples, each of the nodules 802, 804, 806 have the same base width 820 and the same height 822. As a result, the differing slopes of the sidewalls 808, 812, 816 of each of the nodules 802, 804, 806 result in differing sizes of the top surface 810, 814, 818 for each of the nodules 802, 804, 806. The interplay between sidewall slope and the corresponding size of the top surface has been found to impact the aggressiveness of a nodule with an increase in the slope (e.g., a greater angle with respect to the vertical direction) corresponding to an increase in aggressiveness. In some examples, the slope or angle of nodule sidewalls may be greater than as shown for the first nodule 802 in FIG. 8. For example, the angle may range from directly vertical (as in the third nodule 806) to an angle of approximately 45 degrees. [0037] While increasing the slope or angle of sidewalls may increase the aggressiveness of a nodule, the increased slope may reduce the stability or consistency of the nodule over time as well as the service life as explained with reference to FIG. 9. FIG. 9 shows cross-sectional views of the three example nodules 802, 804, 806 of FIG. 8 after the nodules have been worn down to approximately half their original height. The new top surfaces 902, 904 of the first and second nodules 802, 804 shown in FIG. 9 are larger than the original top surfaces 810, 814 shown in FIG. 8 because of the angled sidewalls 808, 812. As a result of this change in the size of top surface, the aggressiveness of the nodules 802, 804 will be reduced. Furthermore, the variability in the aggressiveness of the first nodule 802 (indicative of low stability or consistency) is greater for the second nodule 804 because of the greater slope of the sidewalls 808 of the first nodule 802. In contrast to the first and second nodules 802, 804, the size of the new top surface 906 of the third nodule 806 shown in FIG. 9 is no different than the top surface 818 shown in FIG. 8 because of the vertical sidewalls 816. As a result, the aggressiveness of the third nodule 806 is more consistent over time than the other two nodules 802, 804, which corresponds to better stability.

Additionally, the greater width at the top of the third nodule 806 compared with the top of the first nodule 802 as shown in FIG. 8 may reduce the rate at which the third nodule 806 is worn down relative to the first nodule 802. Thus, while the first nodule 802 may be more aggressive than the third nodule 806, the third nodule 806 is likely to have a longer service life than the first nodule 802 in addition to providing improved stability or consistency during that useful life.

[0038] As demonstrated from the discussion of FIGS. 8 and 9, there are tradeoffs between the aggressiveness, stability, and useful life of nodules that can be defined based on the design of nodules including the angle of nodule sidewalls and the resulting size of the top surface of the nodules. As mentioned above, the impact of the different sidewall angles of the nodules 802, 804, 806 of FIGS. 8 and 9 are based on all three nodules 802, 804, 806 having the same width 820 and height 822. However, the width and height of nodules are additional factors that may be different between different nodules to impact the tradeoffs mentioned above. In particular, FIG. 10 is a graph illustrating the relationship between nodule height and disk aggressiveness derived from tested results. The graph in FIG. 10 is represented using relative units because the impact of a particular height of a nodule on the

aggressiveness of a conditioning disk depends upon other factors (e.g., the nodule width, slope of nodule sidewalls, nodule shape, etc.). Similarly, FIG. 11 is a graph illustrating the relationship (in relative units) between nodule width (at the base) and disk aggressiveness. As shown in FIGS. 10 and 1 1 , testing has shown that the aggressiveness of a conditioning disk exhibits a generally quadratic relationship with both the height and width of nodules on the disk. By way of example, the width of nodules may range from approximately 10 μηι to 100 μηι. In some examples, the height of nodules may range from 10 μηι to 150 μηι. In some examples, the height may range from approximately 75 μηι to 100 μηι.

[0039] Another factor that may contribute to the performance (e.g., the aggressiveness, stability, and/or useful life) of the conditioning disk 102 is the number of nodules positioned on the disk 102. FIG. 12 is a graph illustrating the relationship between the number of nodules and disk aggressiveness (in relative units) derived from tested results. As shown in the illustrated example, disk aggressiveness increases generally linearly with an increase in the number of nodules. While this relationship is linear for a relatively low number of nodules (e.g., less than 30), it is expected that the relationship may not be maintained for very high numbers of nodules (e.g., over 100) because the load created by pressing the conditioning disk 102 against the pad 110 would be relatively evenly distributed across all nodules such that there is an insufficient localized force to produce desired levels of aggressiveness.

However, on the other hand, an increase in the number of nodules is likely to increase the service life and stability of the conditioning disk 102 because the rate of wear on each individual nodule will be reduced.

[0040] As outlined above, there are many factors in the structure of the example nodules disclosed herein including the shape of a nodule (e.g., conical vs. pyramidal), the height of a nodule, the width of a nodule, and the slope of nodule sidewalls. These structural factors, in combination, may define the size of the top surface of a nodule that is to be in direct contact with a polishing pad (e.g., the polishing pad 1 10) to be conditioned, which may affect the performance characteristics of the nodule including aggressiveness, stability, and/or service life. Furthermore, in some instances, changes to any of the nodule design factors can result in tradeoffs between different ones of the performance characteristics. That is, nodules that are designed to be more aggressive often exhibit less stability or consistency over time. Furthermore, such nodules typically wear away at a faster rate resulting in a shorter useful life. By contrast, nodules designed for greater stability or longer life are often less aggressive.

[0041] In some examples, the need to make these tradeoffs is at least partially mitigated through the use of protective structure(s) (e.g., the protective structure(s) 140, 510, 704) as described above. That is, the protective structure(s) serve to relieve load on the nodule to substantially reduce the rate of wear of the nodule, which leads to increased stability and a longer useful life. As a result, nodule geometry may be designed with much more focus on the desired aggressiveness. Of course, nodules may still be designed with geometry consistent with relatively high stability and/or long useful life regardless of the presence of protective structure(s). However, in such examples, the protective structure(s) still serve to protect the nodule. In other words, the reduced wear on the nodules afforded by placing protective structure(s) adjacent thereto enables greater freedom in designing nodules that meet particular needs of different CMP processes (e.g., when different materials are involved).

[0042] In some examples, the level of protection provided by protective structure(s) may depend on the geometry and/or position of the protective structure(s) relative to the adjacent nodule. For example, the closer the height of the protective structure(s) is to the height of the adjacent nodule and/or the larger the area of the upper surface of the protective structure(s) (based on the protective structure shape) relative to the top surface of the adjacent nodule, the more protection the protective structure(s) will provide. Thus, example heights for the protective structure(s) are comparable to the nodule ranging from approximately 10 μηι to 150 μηι. In some examples, the nodule height will be somewhat greater than the height of the protective structure(s). In some examples, the protective structure(s) will be at least 75% the height of the adjacent nodule the protective structure(s) are designed to protect and/or within 50 μηι of the height of the nodule. In some examples, the protective structure(s) may be substantially the same height as the nodule. The width of the protective structure(s) may also be similar to the nodule width (e.g., 10 μηι to 100 μηι). However, to increase the area of the upper surface of the protective structure(s), in some examples, the width may be much higher (e.g., 200 μιτι, 500 μιτι, 1 mm, etc.). Further, the distance between protective structure(s) and the nodule may also play a role in the level of protection provided. In some examples, the distance between the top surface of a nodule and the upper surface of an adjacent protective structure is less than the width of the nodule. Thus, protective structure(s) constructed in accordance with the teachings disclosed herein provide additional design factors that can be adjusted to strike the proper balance between the various tradeoffs in different applications.

[0043] FIG. 13 is a flowchart of an example method to manufacture any of the example prominent surface features 136, 502, 700 of FIG. 1-7 on the example conditioning disk 102 of FIG. 1. The example method begins at block 1302 by identifying performance characteristics for the conditioning disk 102. The performance characteristics may include aggressiveness (e.g., cut rate) and stability (e.g., consistency over time). In some examples, the performance characteristics are specified based on the particular application to which the conditioning disk 102 is to be applied. At block 1304, the example method involves specifying nodule geometry and count based on the performance characteristics. Nodule geometry specifications may include the nodule shape, the nodule height 712, 822 (e.g., relative to the baseline surface 128 of the conditioning disk 102), the nodule width 820 (e.g., at the base), and/or the slope of the sidewalls 202, 204, 206, 208, 506, 808, 812, 816 of the nodule 138, 504, 702, 802, 804, 806. Nodule count refers to the number of nodules 138, 504, 702, 802, 804, 806 included on the conditioning disk 102.

[0044] At block 1306, the example method involves specifying protective structure geometry and position based on the performance characteristics and nodule geometry. Protective structure geometry and position may include the shape of the protective structure(s) 140, 510, 704, the height 710 of the protective structure(s) 140, 510, 704, the area of the upper surface 214, 514, 716 of the protective structure(s) 140, 510, 704, the number of protective structure(s) 140, 510, 704 to surround the nodule, the location of the protective structure(s) 140, 510, 704 around the nodule, and/or the distance of the protective structure(s) 140, 510, 704 from the nodule.

[0045] At block 1308, the example method involves forming the nodule(s) 138, 504, 702, 802, 804, 806 and the protective structure(s) 140, 510, 704 on a baseline surface 128 of the conditioning disk 102. In some examples, the nodule(s) 138, 504, 702, 802, 804, 806 and the protective structure(s) 140, 510, 704 may be integrally formed on the baseline surface 128 of the conditioning disk 102 out of the same material as the underlying substrate. In others examples, the nodule(s) 138, 504, 702, 802, 804, 806 and the protective structure(s) 140, 510, 704 may be separately formed on the baseline surface 128 out of the same or different material as the underlying substrate.

[0046] At block 1310, the example method involves applying a protective film 708 to some or all of the nodule(s) 138, 504, 702, 802, 804, 806. In some examples, the protective film 708 may also be applied to some or all of the protective structure(s) 140, 510, 704 and/or exposed portions of the baseline surface 128 of the conditioning disk 102.

[0047] Although the example method is described with reference to the flowchart illustrated in FIG. 13, many other methods of manufacturing the example conditioning disk 102 in accordance with the teachings disclosed herein may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Similarly, additional operations may be included in the manufacturing process before, in between, or after the blocks shown in FIG. 13.

[0048] From the foregoing, it will be appreciated that methods, apparatus and articles of manufacture disclosed herein provide conditioning disks used in CMP processes that have a significantly longer service life than other known disks because nodules, as the primary component to roughen or conditioning a polishing pad, are protected by adjacent protective structure(s). In addition to increasing the service life of conditioning disks, examples disclosed herein enable the manufacturing of conditioning disks with specific performance characteristics needed in particular applications. In particular, nodule geometry may be specifically designed to increase or decrease the aggressiveness of the conditioning disk while maintaining stability and a long service life because of the protective structure(s).

[0049] Example 1 is a chemical mechanical planarization conditioning disk that includes a substrate, a nodule proj ecting a first height from the substrate, and a protective structure projecting from the substrate. The protective structure is adjacent the nodule. The protective structure has an upper surface at a second height relative to the substrate. An area of the upper surface of the protective structure is greater than a top surface of the nodule.

[0050] Example 2 includes the subj ect matter of Example 1, wherein an edge joining a lateral wall of the protective structure and the upper surface of the protective structure is rounded.

[0051] Example 3 includes the subj ect matter of any one of Examples 1 or 2, wherein the nodule includes an inner structure and a protective film at least partially coating the inner structure.

[0052] Example 4 includes the subj ect matter of Example 3, wherein the protective structure is at least partially coated by the protective film.

[0053] Example 5 includes the subj ect matter of any one of Examples 3 or 4, wherein the protective film is not on the protective structure.

[0054] Example 6 includes the subj ect matter of any one of Examples 3-5, wherein a difference between the first height and the second height corresponds to a thickness of the protective film. [0055] Example 7 includes the subj ect matter of any one of Examples 3-5, wherein a difference between the first height and the second height is less than a thickness of the protective film.

[0056] Example 8 includes the subj ect matter of any one of Examples 3-7, wherein the protective film is a diamond coating.

[0057] Example 9 includes the subj ect matter of any one of Examples 1-8, wherein the protective structure at least partially encloses the nodule.

[0058] Example 10 includes the subject matter of any one of Examples 1-9, wherein the protective structure is one of a plurality of protective structures adjacent the nodule.

[0059] Example 11 includes the subject matter of any one of Examples 1-10, wherein a lateral wall of the protective structure is substantially perpendicular to a baseline surface of the substrate.

[0060] Example 12 includes the subject matter of any one of Examples 1-1 1, wherein the upper surface of the protective structure is substantially parallel with a baseline surface of the substrate.

[0061] Example 13 includes the subject matter of any one of Examples 1 -12, wherein the area of the upper surface of the protective structure is at least five times greater than the top surface of the nodule.

[0062] Example 14 includes the subject matter of any one of Examples 1 -13, wherein the nodule is one of a plurality of nodules proj ecting from the substrate. Each of the plurality of nodules exhibiting substantially a same width and a sidewall positioned at substantially a same angle relative to a direction normal to a baseline surface of the substrate.

[0063] Example 15 includes the subject matter of Example 14, wherein a total number of the nodules on the conditioning disk is less than thirty.

[0064] Example 16 is a chemical mechanical planarization

conditioning disk that includes a baseline surface and a prominent surface feature projecting from the baseline surface. The prominent surface feature includes a nodule having a first surface at an end of the nodule furthest away from the baseline surface. The prominent surface feature includes a protective structure adjacent the nodule. The protective structure has a second surface facing away from and substantially parallel to the baseline surface. An area of the second surface is greater than the first surface.

[0065] Example 17 includes the subject matter of Example 16, wherein a perimeter of the second surface of the protective structure is defined by a rounded edge.

[0066] Example 18 includes the subject matter of any one of Examples 16 or 17, wherein the nodule includes a protective film.

[0067] Example 19 includes the subject matter of Example 18, wherein the first surface of the nodule is at a first height relative to the baseline surface and the second surface of the nodule is at a second height relative to the baseline surface, a difference between the first height and the second height is less than or equal to a thickness of the protective film.

[0068] Example 20 includes the subject matter of any one of Examples 18 or 19, wherein the protective film is a diamond film.

[0069] Example 21 includes the subject matter of any one of Examples 16-20, wherein the protective structure extends entirely around the nodule.

[0070] Example 22 includes the subject matter of any one of Examples 16-20, wherein the protective structure is one of a plurality of protective structures positioned at spaced apart locations around the nodule.

[0071] Example 23 is a chemical mechanical planarization

conditioning disk that includes a nodule proj ecting from a substrate and a protective structure projecting from the substrate adjacent the nodule. The protective structure having a lateral wall and an upper surface. The lateral wall is connected to the upper surface via a rounded edge.

[0072] Example 24 includes the subject matter of Example 23, wherein the nodule projects from the substrate a first height and the protective structure projects from the substrate a second height less than the first height.

[0073] Example 25 includes the subject matter of any one of Examples 23 or 24, wherein an area of the upper surface of the protective structure is greater than a top surface of the nodule. [0074] Example 26 includes the subject matter of any one of Examples 23-25, wherein the upper surface of the protective structure is substantially flat.

[0075] Example 27 includes the subject matter of any one of Examples 23-26, wherein the upper surface of the protective structure is substantially parallel with a baseline surface of the substrate.

[0076] Example 28 includes the subject matter of any one of Examples 23-27, wherein the nodule includes an inner structure and a protective film at least partially coating the inner structure.

[0077] Example 29 includes the subject matter of Example 28, wherein the inner structure of the nodule projects from the substrate a first height and the protective structure projects from the substrate a second height.

[0078] Example 30 includes the subject matter of Example 29, wherein the first height is substantially the same as the second height such that the protective film on the inner structure projects beyond the second height.

[0079] Example 31 includes the subject matter of Example 29, wherein the second height is greater than the first height by less than a thickness of the protective film.

[0080] Example 32 includes the subject matter of any one of Examples 23-31, wherein the protective structure at least partially surrounds the nodule.

[0081] Example 33 includes the subject matter of any one of Examples 23-32, wherein the protective structure is one of a plurality of protective structures adjacent the nodule.

[0082] Example 34 includes the subject matter of Example 33, wherein a combined total area of the upper surfaces of the plurality of protective structure is greater than an area of a top surface of the nodule.

[0083] Example 35 includes the subject matter of any one of Examples 23-32, wherein the nodule is one of a plurality of nodules projecting from the substrate and the protective structure is one of a plurality of protective structures. Each of the plurality of nodules is associated with corresponding ones of the plurality of protective structures. [0084] Example 36 a method of manufacturing a chemical mechanical planarization conditioning disk that includes forming a nodule on a substrate and forming a protective structure on the substrate adjacent to the nodule. An area of an upper surface of the protective structure is greater than a top surface of the nodule.

[0085] Example 37 includes the subject matter of Example 36, wherein the protective structure includes a rounded edge between the upper surface and a lateral wall of the protective structure.

[0086] Example 38 includes the subject matter of any one of Examples 36 or 37, further including coating the nodule with a protective film.

[0087] Although certain example methods, apparatus and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the claims of this patent.

Claims

What Is Claimed Is:

1. A chemical mechanical planarization conditioning disk comprising:

a substrate;

a nodule projecting a first height from the substrate; and

a protective structure projecting from the substrate, the protective structure adjacent the nodule, the protective structure having an upper surface at a second height relative to the substrate, an area of the upper surface of the protective structure being greater than a top surface of the nodule.

2. The chemical mechanical planarization conditioning disk of claim 1, wherein an edge joining a lateral wall of the protective structure and the upper surface of the protective structure is rounded.

3. The chemical mechanical planarization conditioning disk of any one of claims 1 or 2, wherein the nodule includes an inner structure and a protective film at least partially coating the inner structure.

4. The chemical mechanical planarization conditioning disk of claim 3, wherein the protective structure is at least partially coated by the protective film.

5. The chemical mechanical planarization conditioning disk of any one of claims 3 or 4, wherein the protective film is not on the protective structure.

6. The chemical mechanical planarization conditioning disk of any one of claims 3-5, wherein a difference between the first height and the second height corresponds to a thickness of the protective film.

7. The chemical mechanical planarization conditioning disk of any one of claims 3-5, wherein a difference between the first height and the second height is less than a thickness of the protective film.

8. The chemical mechanical planarization conditioning disk of any one of claims 3-7, wherein the protective film is a diamond coating.

9. The chemical mechanical planarization conditioning disk of any one of claims 1-8, wherein the protective structure at least partially encloses the nodule.

10. The chemical mechanical planarization conditioning disk of any one of claims 1-9, wherein a lateral wall of the protective structure is substantially perpendicular to a baseline surface of the substrate.

11. The chemical mechanical planarization conditioning disk of any one of claims 1-10, wherein the upper surface of the protective structure is substantially parallel with a baseline surface of the substrate.

12. The chemical mechanical planarization conditioning disk of any one of claims 1-11, wherein the nodule is one of a plurality of nodules projecting from the substrate, each of the plurality of nodules exhibiting substantially a same width and a sidewall positioned at substantially a same angle relative to a direction normal to a baseline surface of the substrate.

13. The chemical mechanical planarization conditioning disk of claim 12, wherein a total number of the nodules on the conditioning disk is less than thirty.

14. A chemical mechanical planarization conditioning disk comprising:

a baseline surface; and

a prominent surface feature projecting from the baseline surface, the prominent surface feature including a nodule having a first surface at an end of the nodule furthest away from the baseline surface, the prominent surface feature including a protective structure adjacent the nodule, the protective structure having a second surface facing away from and substantially parallel to the baseline surface, an area of the second surface being greater than the first surface.

15. The chemical mechanical planarization conditioning disk of claim 14, wherein a perimeter of the second surface of the protective structure is defined by a rounded edge.

16. The chemical mechanical planarization conditioning disk of any one of claims 14 or 15, wherein the nodule includes a protective film.

17. The chemical mechanical planarization conditioning disk of any one of claims 14-16, wherein the protective structure extends entirely around the nodule.

18. The chemical mechanical planarization conditioning disk of any one of claims 14-17, wherein the protective structure is one of a plurality of protective structures positioned at spaced apart locations around the nodule.

19. A chemical mechanical planarization conditioning disk comprising:

a nodule projecting from a substrate; and

a protective structure projecting from the substrate adj acent the nodule, the protective structure having a lateral wall and an upper surface, the lateral wall connected to the upper surface via a rounded edge.

20. The chemical mechanical planarization conditioning disk of claim 19, wherein an area of the upper surface of the protective structure is greater than a top surface of the nodule.

21. The chemical mechanical planarization conditioning disk of any one of claims 19 or 20, wherein the upper surface of the protective structure is substantially flat.

22. The chemical mechanical planarization conditioning disk of any one of claims 19-21, wherein the nodule is one of a plurality of nodules projecting from the substrate and the protective structure is one of a plurality of protective structures, each of the plurality of nodules associated with corresponding ones of the plurality of protective structures.

23. A method of manufacturing a chemical mechanical planarization conditioning disk, comprising:

forming a nodule on a substrate; and

forming a protective structure on the substrate adjacent to the nodule, an area of an upper surface of the protective structure being greater than a top surface of the nodule.

24. The method of claim 23, wherein the protective structure includes a rounded edge between the upper surface and a lateral wall of the protective structure.

25. The method of any one of claims 23 or 24, further including coating the nodule with a protective film.