TWI333235B - Edge bead removal by an electro polishing process - Google Patents

Description

1333235 发明, INSTRUCTION DESCRIPTION: TECHNICAL FIELD OF THE INVENTION The preferred embodiment of the present invention relates generally to the removal of a deposited conductive layer along the edge of a substrate. More particularly, embodiments of the present invention relate to an electrode constructed to polish a substrate edge during electrochemical mechanical processing of a substrate surface. I [Prior Art] In the fabrication of integrated circuits (1C) and other electronic devices, when a conductive layer is deposited on a substrate (for example, a copper layer for filling features in a dielectric material), it often leads to excessive Copper is deposited on one side of the substrate and surrounds the periphery of the substrate of the face. Excess copper on this surface causes problems such as short circuits in the circuit. In addition, even if the edge portion is a portion of the substrate that is unacceptable, excess copper beyond the edge of the substrate can cause delamination of the copper layer and other problems. Therefore, the excess copper must be removed from both the edge of the substrate and the face prior to subsequent processing of the substrate, and such subsequent processing can include adding # and removing conductive, semiconductive, and dielectric materials. An additional layer or the like to form multiple interconnects of the integrated circuit. Electrochemical mechanical treatment (Ecmp) grinds the substrate by electrochemical decomposition and at the same time a lower mechanical friction force than the conventional chemical mechanical polishing (CMP) process, and the excess is removed from the surface of the substrate surface. Copper. Electrochemical decomposition is performed by applying a bias between the cathode and the surface of the substrate to remove the copper from the surface of the substrate into a surrounding electrolyte solution. The bias voltage can be applied to the substrate surface by a conductive contact disposed on the substrate or by using an abrasive material 3 1333235 which can be used to polish the substrate. The mechanical component of the Ecmp polishing process is provided by the relative motion between the substrate and the abrasive material, the relative motion enhancing the efficiency of removing the copper from the substrate. The direct contact between the substrate and the abrasive material can be removed - to protect the passive layer of copper, thereby being able to be polished and planarized by Ecmp. Conventional CMP only effectively removes the surface of the substrate surface. Excess copper, but failed to remove excess copper from the edge of the substrate because the abrasive material does not contact the edge of the substrate. Therefore, there is a need to provide an edge bead removal step (EBR) between the deposition step and the conventional CMP process. The EBR can occur in the same system used for deposition and includes an additional, time consuming process from spinning the substrate as a nozzle directs the etching solution along the edge of the substrate onto the excess copper. The nozzle for the EBR needs to be adjusted and coordinated so as to exclusively direct the etching solution to the desired edge portion of the substrate. Thus, in this 1C manufacturing, because of the additional EBR step, the yield is slowed, resulting in increased costs, increased deposition system complexity, and the need to use additional consumable materials. φ Therefore, there is a need for an improved method and apparatus for removing a deposited conductive layer along the edge of a substrate. SUMMARY OF THE INVENTION The present invention is generally directed to a method and apparatus for removing a deposited conductive layer using an electrode along the edge of the substrate, the electrode holder constituting an edge of the substrate that can be electrically ground. Electro-grinding of the edge of the substrate can occur simultaneously during electrochemical mechanical processing (Ecmp) of a substrate surface. In one embodiment, a power supply applies a bias voltage between the base 4 1333235 plate and at least two electrodes. The electrodes form a first electrode region at the edge of the substrate at a sufficient potential to electrically polish the edge of the substrate to remove the conductive layer from the edge of the substrate. A second electrode region having a lower potential than the first electrode region is aligned adjacent to the substrate surface during processing to enable Ecmp to be applied to the substrate surface. [Embodiment]

SUMMARY OF THE INVENTION The present invention generally relates to the removal of edge beads (EBR) from a substrate by an electrical polishing process. The electro-grinding process can have one or more electrodes adjacent the edge of the substrate and having a sufficient potential to specifically polish the electrodes of the edge, occurring simultaneously during electrochemical mechanical processing (Ecmp) of the substrate. Although an Ecmp station utilizing the electrode to electrically polish the edge will be disclosed herein, it will be appreciated that the electrode can also be used in an Ecmp station without a polishing pad to electrically polish the edge of the substrate. Furthermore, when the electrode is part of the Ecmp stage itself, the Ecmp station and the polishing pad can be used to polish the substrate. For example, other Ecmp stations can use different carrier heads and/or different ones as described herein. Table assemblies are all within the scope of the invention. 1 depicts a partial cross-sectional view of a non-standard processing station that utilizes a specific embodiment of the abrasive tamper assembly 106 to remove an edge bead from a substrate 120. The processing station 100 includes a carrier head assembly 118 that is designed to hold the substrate 120 against a table assembly 142 disposed in the Ecmp station 132. The substrate 120 is ground with relative motion provided between the substrate 120 and the stage assembly 142. The relative motion can be rotational, horizontal, or some combination thereof, and the relative motion can be provided by either or both of the carrier head assembly 118 and the set of five members 142. An arm 164 coupled to the base i3 supports the carrier securing assembly 118 above the Ecmp stage 132. The carrier head assembly 118 generally includes a drive system 102 that is coupled to the carrier head I for providing at least rotational motion of the carrier head 122. Alternatively, the carrier head 122 can be actuated toward the Ecmp table 132 such that the substrate 120 retained in the carrier head 122 can abut against one of the processing surfaces 104 of the Ecm station 132 during processing. The carrier head 122 includes a housing 124 that defines a center recess and a buckle 126 that retains the substrate 120. The carrier head 122 can be a TITAN HEADTM or TITAN PROFILERTM wafer carrier made by Applied Materials, Inc. of Santa Clara, California. The Ecmp station 132 generally includes a table assembly 142 having an upper stage 114 and a lower stage 148 that are rotatably disposed on the base 158. A bearing 154 between the table assembly 142 and the base 158 facilitates rotation of the table assembly 142 relative to the base 151. A motor 160 provides the rotary motion to the table assembly M2. A top surface 116 of the upper stage 114 can support the abrasive boring assembly 106 thereon. The lower stage 148 is affixed to the upper stage 114 by a plurality of conventional fastening members, such as a plurality of fastening means (not shown), between the upper and lower stages 114, 148. (one of them is shown in Figure 1) to ensure that they are aligned with each other. The upper stage 114 and the lower stage 148 can be made of a single, unitary member as desired. A gas chamber 138 (plenum 138) defined in the stage assembly 142 can be partially formed in at least one of the upper and lower stages 114, 148. In the specific embodiment described in the 1st 1333235 circle, a recessed region 144 partially formed in the lower surface of the upper stage 114 can define at least one hole 118 formed by the gas chamber 138β in the upper stage U4 to allow electrolyte The process may be supplied to the plenum 138 by an electrolyte source 170 flowing through the table assembly 142 and contacting the substrate 120. A cover 150 coupled to the upper stage 114 surrounds the recessed area 144 and partially defines the boundary of the plenum 138. Alternatively, the electrolyte may be dispensed onto the top surface of the abrasive crucible assembly 1 6 using a tube (not shown).

At least one contact assembly 134 is disposed on the table assembly 142 as the polishing pad assembly 1 〇 6 extends to or beyond the upper surface of the polishing pad assembly 106 and is designed to Suitable for electrically coupling the substrate 120 to a power source 166. A counter electrode (described below) of the pad assembly 1-6 is coupled to different terminals of the power source 166 to establish a -potential between the substrate 120 and the counter electrodes. In other words, during processing, the contact assembly 134 applies a bias voltage to the substrate 120 by electrically coupling the substrate 120 to one of the terminals of the power source 166, and the substrate 120 is fixed against the polishing pad assembly. 1〇6. The polishing pad assembly 1〇6 is coupled to the other terminal of the power source 166. The electrolyte is introduced from the electrolyte source 170 and placed in the Ecmp station, and a circuit is completed between the substrate 120 and the counter electrodes. The conductive electrolyte facilitates removal of material from the surface and edges of the substrate 120. Fig. 2 is a partial cross-sectional view showing the polishing pad assembly 1〇6 and the stage assembly 142 of Fig. 1. The polishing pad assembly 106 includes at least one electrically conductive layer 210 and a layer 212 overlying the treated surface 214. In one embodiment, at least one permeable passage 218 is formed through at least the upper layer 212 and extending at least to the conductive layer 210 to allow the electrolyte to be established between the substrate 120 and the conductive layer 210. A conductive path. For some embodiments, it has thousands of channels 218. Part of the channel 218 may be required to polish the face of the substrate 120, while other channels may be required to polish the edge of the substrate. Thus, Figure 2 graphically depicts only a few channels 218, which are preferably more than shown. The conductive layer 210 and the upper layer 212 of the polishing pad assembly 106 can be combined into a unitary assembly using adhesives, bonding, compression, molding, and the like. An example of a polishing pad assembly to which the present invention is applicable and which is beneficial to the present invention is disclosed in U.S. Patent Application Serial No. 1/455,941, issued toK. Abraded conductive abrasive article '', attorney's docket number 4100P4), and U.S. Patent Application Serial No. 1/455,895, filed on Jun. 6, 2003. "Mechanical Grinding of Conductive Abrasive Articles", attorney Docket No. 41 00P5, the entire disclosure of which is hereby incorporated by reference herein in its entirety herein in its entirety the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire all all all all all all all all all all all all all all all all all all each Alloy, woven fabric coated with metal layer, conductive polymer, conductive pad, etc. Conductive metal containing tin, nickel, copper, gold, etc. The conductive metal also contains a corrosion-resistant metal such as coated on activities such as copper, zinc, aluminum, etc. Tin, nickel, or gold above the metal. The conductive alloy contains inorganic alloys and metal alloys, such as bronze, brass, stainless steel, or palladium-tin alloys in other alloys. Magnetic suction, electrostatic attraction can be utilized. A vacuum, an adhesive, or the like is held on the top surface 116 of the upper stage 114 of the stage assembly 142. Other layers, such as a release liner, a liner, and other adhesive layers, may be disposed on the conductive layer 210 and above. Between the stages 114 to facilitate easy processing from the processing station 100 'insert, and remove V5' 5'52'5 ^ the abrasive 塾 assembly 1 〇 6» the conductive layer 210 contains at least one ~ internal reverse electrode 209 and an external counter electrode 211, which are not separated from each other by an electric 1, e W 213 or other dielectric spacer. A first terminal 202 rib is known to fit the internal electrode 209 to the a power source 166, and a second terminal 2 〇3 π assists the external electrode 211 to the power source 166. For example, stainless steel screws (not shown) are respectively fixed to the bow wires 204, 205 of the power source 1 66 and the The power supply 166 supplies a first voltage to the external electrode 211, and the first voltage is higher than the first current supplied to the internal electrode 209. Thus, the guide and the like 1: layer 210 comprises the last independent electrode region defined by the electrodes 2〇9 Isolated from each other. The conductive layer should also be made of a material that is compatible with the chemical properties of the electrolyte to minimize interference with the electrodes 209 2 1 1 . For example, the metal in the electrolyte chemistry is stable. The electrode region 211 can be substantially circumscribed to the outer periphery of one of the polishing pad assemblies 1 〇 6 such that when the substrate 12G and the gantry group 142 move relative to each other, the electrode of the external electrode 211 The region extends at least to one of the edges 220 of the substrate 12. When the substrate 120 and the stage assembly 142 move relative to each other, the electrode region of the internal electrode 2〇9 extends over an area corresponding to one of the substrates 12” The proximity of the external electrode 211 relative to the edge end 22〇 and the proximity of the internal electrode 209 to the surface 221 ensure that the electrode regions of the electrodes 2〇9, 211 extend to appropriate portions of the substrate 12〇. During Ecmp, the electrode regions of each of the electrodes 209, 211 are substantially maintained adjacent to the edge 220 of the substrate 120 and the face 221, respectively. The carrier head can be swept so that the edge 220 is sometimes tied to the inner counter electrode 209. 9 1333235

In operation, the first electric bunker applied to the internal electrode may cause the face 221 of the substrate 120 to undergo a typical Ecmp process due to electrochemical decomposition and direct contact between the steel layer 222 and the handle substrate 214. Caused by friction. The contact between the copper layer 222 and the processing surface 214 can remove a passive layer 222 from the copper layer and can polish and planarize the surface 221. The copper layer 222 extending onto the edge 220 of the substrate 12 is not yet removed in a separate edge bead removal (EBR) step, as shown in FIG. 2, before the Ecmp polishing of the substrate 120. except. However, since the copper layer 222 surrounding the edge 22 is not in contact with the processing surface 214, the Ecmp cannot remove the copper layer 222 surrounding the edge 220.

In a particularly advantageous aspect of the invention, during the Ecmp, a high voltage difference between the external electrode 211 and the substrate 120 can remove the steel layer 222 along the edge 220 of the substrate 12 without the need for the additional Separate Ebr steps. The power source 166 supplies the second voltage to the external electrode 211 such that the voltage difference between the external electrode 211 and the substrate 12 is sufficient to remove the copper layer 222 under the bias, without the need for the processing. Any wear on surface 214. Although the pure layer protects the copper layer 22 from the voltage difference between the substrate 120 and the internal electrode 209, the passivation layer does not protect the copper layer 222 from the substrate at the second voltage. 12〇 and a high voltage difference between the external electrodes 211. Thus, the second voltage supplied to the external electrode 211 can remove or polish the copper layer 222 surrounding the edge 220 of the substrate 2 via an electrical polishing process. The control of removing the copper layer 222 from the edge 22 of the substrate 12 is only required to adjust the voltage supplied to the external electrode 211. Since the external electrode 211 only faces or is adjacent to the edge 220, the outer 10 1333235

The electrode 211 can be specifically removed from the edge 220 of the substrate 120 and possibly a small portion of the perimeter of the face 221 adjacent the edge 220. Therefore, the external electrode 221 only electrically polishes the edge 220, and the remaining portion of the substrate 120 facing or adjacent to the internal electrode 209 is ground by the Ecmp technique. The number of copper layers 222 removed around the periphery of the face 221 depends on the level of the second voltage of the external electrode 211 and the proximity of the outer electrode 211 to the periphery of the face 221 . Electro-grinding of the edge 220 can occur simultaneously with Eemp of the face 221 such that the copper layer 222 is not affected by throughput during processing from the edge 220 to the substrate 120.

The voltage supplied to the internal electrode 209 depends on the Ecmp system and the chemistry used therewith to achieve the desired Ecmp properties such as rate, polishing profile 'flattening, tantalum and surface roughness. To allow Ecmp polishing of the face 221 of the substrate 120, the power supply 166 is preferably supplied with a positive bias of approximately zero volts (V) (typically grounded) to the substrate 120, and preferably at zero V to approximately The first voltage is supplied to the internal electrode 209 at -5 V, most preferably about -2 V or -3 V. The power source 166 supplies the second voltage to the external electrode 211 at a sufficient voltage to electrically polish the copper layer 222. Therefore, the power source 166 preferably supplies the second voltage to the external electrode 2 1 1 at -4V to -20V, and most preferably about -10V. Although a minimum of two separate electrode regions is required to provide separate electro-grinding and Ecmp for the substrate as described herein, additional electrodes providing additional electrode regions can be utilized to modify the Ecmp performance and can be traversed. The surface 221 of the substrate 120 achieves good uniformity. Preferably, the number of electrode regions varies from 3 to 5' and the outermost electrode region is dedicated to electrically grinding the copper 11 1333235 layer 22 2 from the edge 220, such as provided by the outer electrode 211.

Figure 3 shows a bottom view of a five zone conductive layer 310 for the Ecmp stage, which simultaneously provides polishing of the substrate and removal of the edge bead. The conductive layer 310 comprises Providing five electrodes 306, 307, 308, 309, 311» of the five zones - the gap 313 can separate the electrodes 306, 3 07, 30 8 , 309, 31 1 'each electrode comprises for coupling to a power source Individual terminals 316, 317, 318, 319, 321 . Typical gaps of 1.0 to 2 mm are 3 1 3 to minimize interference in each interval. Figure 4 shows a graph illustrating one from the electrodes 306, 307, 308,

Each of 3 09, 3 1 1 has an effect on the shape of one of the substrates along each of its radii. Curves 406, 407' 408, 409, 411 represent the percentage of the electrodes 3 06, 3 07, 308, 309, 311 that affect the shape, respectively. As shown by the curve 411, the electrode region formed by an external electrode removes copper only from the edge of the substrate. The relative movement between the substrate and the conductive layer 31 during processing can also remove copper from the edge of the substrate by the electrode regions formed by the electrodes adjacent to the external electrodes. Therefore, the external electrode and the bias of the electrode adjacent to the external electrode as needed provide a sufficiently high voltage difference relative to the substrate to remove copper by electropolishing, and the bias of the remaining electrodes can be Ecmp. Figure 5 shows a graph which directly illustrates the copper thickness on a substrate before Ecmp as indicated by curve 501 and after Ecmp as indicated by curve 502, and uses at least two electrode regions to Electro-grinding provides edge bead removal while enabling Ecmp on the face of the substrate. As shown in the curve 501, in an edge bead removal step, since the thickness does not become zero at the outer diameter, the thickness at the edge of the wafer (e.g., corresponding to 12 1333235 146-1 50 mm) The radius) proves that the edge bead sucking beads have been removed before Ecmp. The curve 052 shows that the face (e.g., the halfway between the temple and the 毫米46 mm) has been ground by Ecmp. The curve 5〇2 is further illustrated in #5〇3 to electrically grind the conductive layer from the edge because the thickness at this point has reached zero. Although the foregoing is directed to other and further embodiments of the present invention, the scope is determined by the following patent application [circular brief description] in order to understand in detail the type of the above-described features of the present invention - the present invention - In particular, the above description may be referred to the specific embodiments, and the description of the embodiments is set forth in the accompanying drawings. However, it is to be understood that the appended claims are only illustrative of the embodiments of the invention, and are not intended to

DETAILED DESCRIPTION OF THE INVENTION The present invention can be devised without being separated from its basic scope, and its first drawing is a partial cross-sectional side view of a processing station of an electrochemical mechanical processing (Ecmp) system. Figure 2 is a partial cross-sectional view of one embodiment of a polishing pad assembly illustrating a two-region reverse electrode architecture capable of removing copper from the edge of the substrate. The third aspect is a bottom view of a five-zone counter electrode for an Ecmp system that simultaneously polishes one side of the substrate and the edge of the substrate, thus eliminating the need for a conventional edge bead removal step. The fourth line is a curve 圊' which illustrates the contribution of each of the opposing electrodes (as described in Section 3) to the abrasive profile and the edge of the substrate. 13 1333235 Figure 5 is a graph illustrating the copper thickness on a substrate before and after the use of an electrode to provide Embp for edge bead removal via electrospinning. [Main component symbol description]

100 Processing Station 102 Drive System 104 Processing Surface 106 Abrasive Pad Assembly 108 Hole 114 Upper Table 116 Top Surface 118 Carrier Head Assembly 120 Substrate 122 Carrier Head 124 Housing 126 Buckle 130 Base 132 Ecmp Table 134 Contact Assembly 138 Air Chamber 142 Table assembly 144 recessed area 146 positioning pin 148 lower table 150 cover 154 bearing 158 base 160 motor 166 power supply 170 electrolyte source 202 first terminal 203 second terminal 204 ' 205 fixed lead 209 internal reverse electrode 210 conductive layer 211 external reverse To the electrode 212, the upper layer 213, the gap 214, the processing surface 218, the transparent channel 220, the edge 221, the surface 14, the first layer, the surface of the copper layer 306' 307 ' 308 ' 309 ' 3 11 , the electrodes 316 , 317 , 318 , 319 ' 321 terminal gap 502 curve 3 10 five Zone conductive layer 313 % 406, 407, 408, 409, 41 1 ' 501, 503

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Claims (1)

1333235 A pick-up, patent application scope: 1. A method for processing a substrate, comprising: contacting a substrate with a polishing pad assembly, the polishing pad assembly comprising: a conductive portion and an upper portion, the upper portion having a processing surface in contact with one surface of the substrate, wherein the conductive portion has a first electrode and a second electrode; and an electrical bias is applied to the first electrode of the polishing pad assembly to be adjacent to the surface of the substrate Forming a first electrode region having a first voltage potential selected to electrochemically mechanically (Ecmp) the surface of the substrate; and applying an electrical bias to the second electrode of the polishing pad to Forming a second electrode region having a second voltage potential adjacent to an edge of the substrate adjacent to the substrate member, the potential is selected to simultaneously electrically polish the substrate around the substrate during the Ecmp period a material formed on the edge, wherein the second voltage potential is higher than the first voltage. 2. The method of claim 2, further comprising adjusting the application to the non-physical entity A voltage potential on the first electrode of the polishing pad assembly surrounding the edge of the substrate is contacted to control electrical polishing of the edge. 3. The method of claim 1, wherein the first and second electrode regions are formed by at least two concentric electrodes. The method of claim 3, wherein the voltage difference between the substrate and the first electrode section is less than 5 volts. 5. The method of claim 3, wherein the voltage difference between the substrate and the second electrode section is between 4 volts and 20 volts. 6. The method of claim 3, further comprising providing a predetermined abrasive profile by forming an additional electrode region facing the surface of the substrate. 7. The method of claim 1, further comprising removing a portion of the deposited conductive layer along the edge of the substrate at a higher removal rate, the rate being higher than the conductive layer A portion covers the rate of the surface of the substrate. 8. An apparatus for processing a substrate, comprising: a polishing pad assembly including a conductive portion and an upper portion, the upper portion having a processing surface in contact with a surface of the substrate, wherein the The conductive portion includes: a first electrode region 'which faces one side of the substrate and extends over a region corresponding to the surface of the substrate and is selected to enable electrochemical mechanical processing (Ecmp) of the surface a voltage potential; a second electrode region adjacent to an edge of the substrate that is not physically contacting the processing surface of the polishing pad assembly, the second 17 1333235 electrode region being at a second voltage potential, the second potential Selecting to electrically polish a material formed around the edge of the substrate; and at least one power source adapted to supply the first voltage potential to the first electrode region and to supply the second voltage potential to the second Electrode zone. 9. The device of claim 8, wherein the second voltage potential is higher than the first voltage potential. 10. The device of claim 8 wherein the first and second electrode regions are formed by at least two concentric electrodes. 11. The apparatus of claim 8, wherein the first electrode region is formed by an internal electrode adjacent to a surface of the substrate. 12. The device of claim 8 wherein the second electrode region is formed by substantially circumscribing an outer periphery of one of the polishing pad assemblies by an outer electrode adjacent the edge of the substrate. 13. The device of claim 8 wherein the voltage difference between the substrate and the first electrode section is less than 5 volts. 18 1333235 14. The apparatus of claim 8 wherein the voltage difference between one of the electrode sections is 4 volts and 20 volts. 4 15. The device of claim 8 is a device having a plurality of additional electrode regions on the surface. Each additional electrode is selected to be Ecmp and to provide a predetermined abrasive profile. Between the substrate and the second. Containing the voltage potential of the region facing the substrate 19