JP2008513596A - Electromechanical treatment of full-sequence metal and barrier layers - Google Patents

Abstract

Methods and apparatus for electrochemically processing metal materials and barrier materials are provided. In one embodiment, a method of electrochemically treating a substrate comprises establishing a conductive path through an electrolyte between an exposed layer of barrier material on the substrate and an electrode, and with a force less than about 2 psi. Pressing the substrate against a processing pad assembly; providing movement between the substrate and a pad assembly in contact with the substrate; and in a barrier processing station during a first electrochemical processing step And electrochemically removing a portion of the exposed layer.
[Selection] Figure 8

Description

Background of the Invention

Field of Invention
[0001] Embodiments of the present invention generally relate to methods of electrochemical processing.

Explanation of related technology
[0002] Electrochemical mechanical planarizing (ECMP) removes conductive material from a substrate surface by electrochemical dissolution while simultaneously reducing the substrate with less mechanical wear compared to conventional planarization processes. This technique is used for polishing. ECMP systems are generally suitable for depositing conductive material on the substrate by reversing the polarity of the bias. Electrochemical dissolution is performed by applying a bias between the cathode and the substrate surface to remove the conductive material from the substrate surface into the surrounding electrolyte. Typically, the bias is applied to the substrate surface by a conductive polishing material on which the substrate is processed. The mechanical component of the polishing process is performed by providing a relative motion between the substrate and the conductive abrasive material, which enhances the removal of the conductive material from the substrate.

  [0003] In many conventional systems, the ECMP of the conductive film is performed after a conventional chemical mechanical process for barrier removal. This process dichotomy (eg, ECMP and CMP on a single system) requires different utilities and process consumables, resulting in higher costs for the owner. Also, since most ECMP processes utilize a low contact pressure between the substrate being processed and the processing surface, the heads used to hold the substrate during processing are typically high contact. When utilized in a conventional CMP process with pressure, it does not provide strong processing performance, resulting in deep erosion of conductive material disposed in trenches or other features. Since the removal rate of conventional low pressure CMP barrier layer processing is typically less than about 100 liters / minute, conventional barrier material CMP processing using low pressure is not suitable for mass production. Thus, a system that is capable of removing barrier materials such as ruthenium, tantalum, tantalum nitride, titanium, titanium nitride, etc. via electrochemical processing would be advantageous.

  [0004] Accordingly, there is a need for improved methods and apparatus for electrochemical processing of metals and barrier materials.

Summary of the Invention

  [0005] Embodiments of the present invention generally provide a method of treating a barrier and metal disposed on a substrate in an electromechanical polishing system. Methods and apparatus for electrochemically processing metals and barrier materials are provided. In one embodiment, a method of electrochemically treating a substrate comprises establishing a conductive path via an electrolyte between an exposed layer of barrier material on the substrate and an electrode, and about 2 psi. Pressing the substrate against the processing pad assembly with less force, providing movement between the substrate and the pad assembly in contact with the substrate, and a first electrical power in the barrier processing station Electrochemically removing a portion of the exposed layer during a chemical treatment process.

  [0006] In another embodiment, a method for electrochemically processing a substrate comprises: removing a conductive layer with a barrier layer disposed thereon at a first processing station of the system; Electrochemically removing the barrier layer at a second processing station of the system using a low substrate contact pressure. The system may include a processing station disposed between the first processing station and the second processing station for removal of the remaining conductive layer using a multi-step removal process.

  [0007] In another embodiment, the method comprises establishing a conductive path via an electrolyte between an exposed layer of barrier material on the substrate and an electrode, and in a barrier processing station. During the first electrochemical treatment step, electrochemically removing a portion of the exposed layer and during or immediately before the breakthrough of the exposed layer of barrier material, Detecting an end point of a chemical treatment process; electrochemically treating the exposed layer of the barrier material in a second electrochemical treatment process within the barrier treatment station; and Detecting an end point of the processing step.

  [0008] In another embodiment, a method of electrochemically processing a substrate includes removing a conductive layer with a barrier layer disposed thereon at a first processing station of the system; Electrochemically removing the barrier layer at a processing station. The system may include a processing station disposed between the first processing station and a second processing station for removal of the remaining conductive layer using a multi-step removal process.

  [0009] In order to provide a more thorough understanding of the manner in which the above-described embodiments of the invention are implemented, a more specific description of the invention, briefly described above, is shown in the accompanying drawings. This can be done with reference to the embodiment. However, the attached drawings are merely illustrative of exemplary embodiments of the present invention and, therefore, should not be considered as limiting the scope of the present invention, but recognize other equally effective embodiments. It should be noted that

  [0024] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements of one embodiment may be advantageously incorporated into other embodiments without requiring further details.

Detailed description

  [0025] Embodiments are provided for systems and methods for removal of conductive and barrier materials from a substrate. Although the embodiments disclosed below focus primarily on removing material, eg, planarization, from the substrate, the teachings disclosed herein teach the substrate and the electrodes of the system. Is intended to be used to electroplate a substrate by reversing the polarity of the electrical bias applied between.

apparatus
[0026] FIG. 1 is a plan view of one embodiment of a planarization system 100 having an apparatus for electrochemically processing a substrate. The exemplary system 100 generally includes a factory interface 102, a loading robot 104, and a planarization module 106. The loading robot 104 is located near the factory interface and the planarization module to facilitate transfer of the substrate 122 between the factory interface 102 and the planarization module 106.

  [0027] The controller 108 is provided to facilitate control and integration of the modules of the system 100. The controller 108 includes a central processing unit (CPU) 110, a storage device 112, and a support circuit 114. The controller 108 is coupled to various components of the system 100, for example, to facilitate control of the planarization process, cleaning process, and transfer process.

  [0028] The factory interface 102 generally includes a cleaning module 116 and one or more wafer cassettes 118. The interface robot 120 is employed to transfer the substrate 122 between the wafer cassette 118, the cleaning module 116, and the input module 124. Input module 12 is positioned to facilitate transfer of substrate 122 between planarization module 106 and factory interface 102 by a gripper, such as a vacuum gripper or mechanical gripper.

  [0029] The planarization module 106 includes at least a first ECMP station 128 disposed within an environmentally controlled enclosure 188. Examples of planarization module 106 that can accommodate benefits from the present invention are MIRRA®, MIRRA MESA ™, REFLEXION (all available from Applied Materials, Inc., Santa Clara, Calif.). ®, REFLEXION LK® and REFLEXION LK Ecmp ™ CMP system. Other planarization modules, including those that use processing pads, planarization webs, or combinations thereof, and those that move the substrate relative to the planarization surface in a rotational, linear or other planar motion are also described It can adapt to the benefits from the invention.

  In the embodiment depicted in FIG. 1, the planarization module 106 includes a first ECMP station 128, a second ECMP station 130, and a third ECMP station 132. Mass removal of the conductive material disposed on the substrate 122 can be performed via an electrochemical dissolution process at the first ECMP station 128. After a large amount of material removal at the first ECMP station 128, the remaining conductive material is removed from the substrate at the second ECMP station 130 via a multi-step electromechanical process and the multi-step process. A portion is configured to remove the remaining conductive material. It is contemplated that one or more ECMP stations may be utilized to perform the multi-step removal process after a mass removal process performed at different stations. Alternatively, each of the first ECMP station 128 and the second ECMP station 130 can perform both removal of a large amount of conductive material and multi-step conductive material removal on a single station. May be used. It is also contemplated that all ECMP stations (eg, the three stations of module 106 depicted in FIG. 1) may be configured to process the conductive layer in a two-step removal process.

  [0031] The exemplary planarization module 106 also includes a transfer station 136 and a carousel 134 disposed on the top or first side 138 of the machine base 140. In one embodiment, transfer station 136 includes an input buffer station 142, an output buffer station 144, a transfer robot 146, and a load cup assembly 148. The input buffer station 142 receives a substrate from the factory interface 102 by the loading robot 104. The loading robot 104 is also used to return the polished substrate from the output buffer station 144 to the factory interface 102. The transfer robot 146 is used to move the substrate between the buffer stations 142, 144 and the load cup assembly 148.

  [0032] In one embodiment, the transfer robot 146 includes two gripper assemblies, each having a pneumatic gripper finger that holds the substrate at the edge of the substrate. The transfer robot 146 may transfer the substrate to be processed from the input buffer station 142 to the load cup assembly 148 and simultaneously transfer the processed substrate from the load cup assembly 148 to the output buffer station 144. An example of a transfer station that can be used to advantage is described in US Pat. No. 6,156,124 issued December 5, 2000 to Tobin.

  [0033] The carousel 134 is centrally located on the base 140. The carousel 134 typically includes a plurality of arms 150, each supporting a planarizing head assembly 152. The two arms 150 depicted in FIG. 1 are shown watermarked so that the planarization surface 126 of the transfer station 136 and the first ECMP station 128 can be seen. The carousel 134 can be indexed so that the planarization head assembly 152 can be moved between the planarization stations 128, 130, 132 and the transfer station 136. One carousel that can be used to advantage is described in US Pat. No. 5,804,507, issued September 8, 1998 to Periov et al.

  [0034] A conditioning device 182 is disposed on the base 140 near each of the planarization stations 128, 130, 132. Conditioning device 182 periodically conditions the planarizing material disposed in stations 128, 130, 132 to maintain a uniform planarization result.

  [0035] FIG. 2 depicts a cross-sectional view of one of the planarization head assemblies 152 positioned over one embodiment of the first ECMP station 128. As shown in FIG. The second and third ECMP stations 130, 132 can be similarly configured. The planarization head assembly 152 generally comprises a drive device 202 coupled to the planarization head 204. The drive 202 generally provides at least rotational movement with respect to the planarizing head 204. The planarization head 204 further provides a first ECMP station 128 so that the substrate 122 held by the planarization head 204 can be positioned opposite the planarization surface 126 of the first ECMP station 128 during processing. Can be actuated. The drive 202 is coupled to a controller 108 that provides a signal to the drive 202 to control the rotational speed and direction of the planarizing head 204.

  [0036] In one embodiment, the planarizing head may be a TITAN HEAD ™ or TITAN PROFILER ™ wafer carrier manufactured by Applied Materials. Generally, the planarizing head 204 includes a housing 214 and a retaining ring 224 that defines a central recess in which the substrate 122 is retained. The retaining ring 224 binds the substrate 122 disposed within the planarization head 204 to prevent the substrate from slipping under the planarization head 204 during processing. The retaining ring 224 can be formed of a plastic material such as PPS or PEEK, a conductive material such as stainless steel, Cu, Au, or Pd, or a combination thereof. It is further contemplated that the conductive retaining ring 224 may be electrically biased to control the electric field during ECMP. Conductive or biased retaining rings tend to slow down the polishing rate near the edge of the substrate. It is contemplated that other planarizing heads may be utilized.

  [0037] The first ECMP station 128 generally includes a platen assembly 230 that is rotatably disposed on the base 140. Platen assembly 230 is supported on base 140 by bearings 238 so that platen assembly 230 can be rotated relative to base 140. The area of the base 140 constrained by the bearing 238 is open and provides a conduit for electrical, mechanical, pneumatic, control signals and connections that communicate with the platen assembly 230.

  [0038] Conventional bearings, rotary unions and slip rings, collectively referred to as rotary coupler 276, transfer electrical, mechanical, fluid, pneumatic, control signals and connections between base 140 and rotary platen assembly 230. Provided to be able to combine. The platen assembly 230 is typically coupled to a motor 232 that provides rotational movement to the platen assembly 230. The motor 232 is coupled to the controller 108 that provides signals for controlling the rotational speed and direction of the platen assembly 230.

  [0039] The top surface 260 of the platen assembly 230 supports the processing pad assembly 222. The processing pad assembly can be held against the platen assembly 230 by magnetic force, attractive force, vacuum, clamping, bonding, or the like.

  [0040] A plenum 206 is defined in the platen assembly 230 to facilitate uniform distribution of electrolyte to the planarization surface 126. Multiple channels, described in more detail below, allow the electrolyte provided from the electrolyte source 248 to the plenum 206 to flow uniformly through the platen assembly 230 and contact the substrate 122 during processing. The platen assembly 230 is formed. It is contemplated that different electrolyte components can be provided during different processing stages or to different ECMP stations 128, 130, 132.

  [0041] The processing pad assembly 222 includes an electrode 292 and at least a planarization portion 290. The electrode 292 is typically composed of a conductive material such as stainless steel, copper, aluminum, gold, silver, and tungsten, among others. The electrode 292 can be hardened, impermeable to electrolyte, permeable to electrolyte, or perforated. At least one contact assembly 250 extends over the processing pad assembly 222 and is adapted to electrically couple a substrate being processed on the processing pad assembly 222 to the power source 242. The electrode 292 is also coupled to the power source 242 so that a potential can be established between the substrate and the electrode 292.

  [0042] Meter 244 is provided to sense a measure indicative of the electrochemical process. Meter 244 may be coupled or positioned between power source 242 and at least one of electrode 292 or contact assembly 250. The meter 244 can also be integrated with the power source 242. In one embodiment, the meter 244 is configured to provide the controller 108 with a measure that indicates processing such as charge, current, and / or voltage. This measure can be utilized by the controller 108 to adjust process parameters in the field or to facilitate detection of endpoints or other process steps.

  [0043] A window 246 is provided through the pad assembly 222 and / or the platen assembly 230 and is configured such that a sensor 254 positioned under the pad assembly 222 can sense a measure of polishing performance. ing. For example, the sensor 254 can be an eddy current sensor or an interferometer, among other sensors. The measure provided to the controller 108 by the sensor 254 provides information that can be utilized to handle profile adjustment in situ, endpoint detection or detection of another point in the electrochemical process. In one embodiment, the sensor 254 is an interferometer capable of producing a collimated beam that is directed to and applied to the surface of the substrate 122 to be polished during processing. The interference between the reflected signals indicates the thickness of the conductive layer of the material being processed. One sensor that can be used to advantage is described in US Pat. No. 5,893,796, issued April 13, 1999 to Birang et al. This is incorporated herein by reference.

  [0044] An embodiment of a processing pad assembly 222 suitable for removal of conductive material from the substrate 122 may include a planarizing surface 126 that is generally substantially dielectric. Other embodiments of the processing pad assembly 222 suitable for removal of conductive material from the substrate 122 may include a planarizing surface 126 that is generally substantially conductive. At least one contact assembly 250 is provided to couple the substrate to a power source 242 so that the substrate can be biased with respect to the electrode 292 during processing. An aperture 210 formed through the planarization layer 290 allows the electrolyte to establish a conductive path between the substrate 122 and the electrode 292.

  [0045] In one embodiment, the planarization portion 290 of the processing pad assembly 222 is a dielectric such as polyurethane. An example of a processing pad assembly that can accommodate the benefits from the present invention was filed on June 6, 2003 (titled “CONDUCTIVE PLANARIZING ARTICLE FOR ELECTROCHEMICAL MECHANIC PLANARIZING”). US patent application Ser. No. 10 / 455,941 by Hu et al., Filed Jun. 6, 2003 (titled “CONDUCTIVE PLANARIZING ARTICLE FOR ELECTROCHEMICAL MECHANIC PLANARIZING”). U.S. patent application Ser. No. 10 / 455,895 to Hu et al.

  [0046] FIG. 3A is a partial cross-sectional view of the first ECMP station 128 through two contact assemblies 250, and FIGS. 4A-4C are side views of one of the contact assemblies 250 shown in FIG. It is an exploded view and sectional drawing. The platen assembly 230 includes at least one contact assembly 250 that protrudes therefrom and is coupled to a power source 242 adapted to bias the surface of the substrate 122 during processing. Contact assembly 250 may be coupled to platen assembly 230, a portion of processing pad assembly 222, or an independent element. Although two contact assemblies 250 are shown in FIG. 3A, any number of contact assemblies may be utilized and distributed in any number of configurations relative to the centerline of the platen assembly 230. Good.

  [0047] The contact assembly 250 is generally electrically coupled to the power source 242 via the platen assembly 230, and at least partially via a respective aperture 368 formed in the processing pad assembly 222. It is possible to move so that The position of the contact assembly 250 can be selected to have a predetermined configuration across the platen assembly 230. For a given process, the individual contact assemblies 250 can be repositioned to different apertures 368 and apertures that do not contain contact assemblies allow electrolyte flow from the plenum 206 to the substrate ( The stopper 392 (as shown in FIGS. 3D and 3E) can be plugged or the nozzle 394 can be plugged. One contact assembly that can accommodate the benefits from the present invention is described in US patent application Ser. No. 10 / 455,239 filed May 23, 2003 by Butterfield et al.

  [0048] Although the embodiment of contact assembly 250 described below with respect to FIG. 3A depicts a rotating ball contact, contact assembly 250 is alternatively suitable for electrically biasing substrate 122 during processing. A structure or assembly having a conductive top layer or surface may also be provided. For example, as depicted in FIG. 3B, the contact assembly 250 can include a polymer matrix 354 having conductive particles 356 dispersed therein, or a conductive material or conductive composite, such as a conductive coating fabric. May include a pad structure 350 having an upper layer 352 formed from (i.e., the conductive element is integrally dispersed with or comprises the material comprising the upper layer). Pad structure 350 may include one or more apertures 210 formed through the pad structure for delivery of electrolyte to the top surface of the pad assembly. Another example of a suitable contact assembly is described in US patent application Ser. No. 10 / 940,603 filed Sep. 14, 2004 by Mao et al.

  [0049] In one embodiment, each of the contact assemblies 250 includes a hollow housing 302, an adapter 304, a ball 306, a contact element 314, and a clamp bushing 316. Ball 306 has a conductive outer surface and is movably disposed within housing 302. The ball 306 is disposed in a first position having at least a portion of the ball 306 extending above the planarizing surface 126 and at least a second position where the ball 306 is substantially flush with the planarizing surface 126. be able to. It is also contemplated that the ball 306 may move completely below the planarization surface 126. Ball 306 is generally suitable for electrically coupling substrate 122 to power source 242. It is contemplated that a plurality of balls 306 for biasing the substrate may be disposed within a single housing 358, as depicted in FIG. 3C.

  [0050] The power supply 242 typically provides a positive electrical bias to the ball 306 during processing. During planarization of the substrate, the power supply 242 may optionally apply a negative bias to the ball 306 to minimize chemical disruption to the ball 306 due to process chemical reactions.

  [0051] The housing 302 is configured to provide a conduit for electrolyte flow from the source 248 to the substrate 122 during processing. The housing 302 is manufactured from a dielectric that is compatible with the chemical reaction of the process. A seat 326 formed in the housing 302 prevents the ball 306 from exiting the first end 308 of the housing 302. The sheet 326 may optionally include one or more grooves 348 formed in the sheet that allow fluid flow to exit the housing 302 between the ball 306 and the sheet 326. . Maintaining fluid flow through the ball 306 can minimize the tendency of chemical reactions of the process acting on the ball 306.

  [0052] Contact element 314 is coupled between clamp bushing 316 and adapter 304. Contact element 314 is generally configured to substantially or completely electrically connect adapter 304 and ball 306 depending on the range of positions of the ball within housing 302. In one embodiment, the contact element 314 may be configured as a spring structure.

  [0053] In the embodiment depicted in FIGS. 3 and 4A-4C and shown in detail in FIG. 5, the contact element 314 includes a plurality of curved portions 344 extending from the annular base 342 in a polar array. Including the annular base. The flexure 344 is typically manufactured from an elastic and conductive material suitable for the chemical reaction of the process. In one embodiment, the curved portion 344 is made from gold-plated beryllium copper.

  [0054] Returning to FIGS. 3A and 4A, 4B, the clamp bushing 316 includes an overhang head 424 having a threaded post 422 extending from the overhang head 424. FIG. The clamp bushing 316 can be made from a dielectric or conductive material, or a combination thereof, and in one embodiment is made from the same material as the housing 302. The overhang head 424 prevents the flexure 344 of the contact element 314 from distorting the ball 306 to prevent deflection, restraint and / or damage to the flexure 344 during assembly of the contact assembly 250 and within the range of movement of the ball 306. The curved portion 344 is maintained at an acute angle with respect to the centerline of the contact assembly 250 so that it is positioned to spread around the surface.

  [0055] The ball 306 may be solid or hollow and is typically manufactured from a conductive material. For example, the ball 306 can be manufactured from a polymer material filled with a conductive material such as metal, conductive carbon or graphite, among other metals, conductive polymers, or conductive materials. Alternatively, the ball 306 may be formed from a solid or hollow core that is coated with a conductive material. The core may be non-conductive and may be at least partially coated with a conductive coating.

  [0056] The ball 306 is generally actuated toward the planarization surface 126 by at least one of spring force, buoyancy, or flow force. In the embodiment depicted in FIG. 3, the flow from electrolyte source 248 through the flow path formed by adapter 304 and clamp bushing 316 and platen assembly 230 causes ball 306 to contact the substrate during processing.

  FIG. 6 is a cross-sectional view of one embodiment of the second ECMP station 130. The first ECMP station 128 and the second ECMP station 130 can be similarly configured. The second ECMP station 130 generally includes a platen 602 that supports a generally conductive processing pad assembly 604. The platen 602 can be configured similar to the platen assembly 604 described above to deliver electrolyte through the processing pad assembly 604, or the platen 602 can be placed on the planarized surface of the processing pad assembly 604. There may be a fluid delivery arm 606 disposed near the platen that is configured to deliver fluid. Platen assembly 602 includes at least one of meter 244 or sensor 254 (shown in FIG. 2) to facilitate endpoint detection.

  [0058] In one embodiment, the processing pad assembly 604 includes an insertion pad 612 sandwiched between a conductive pad 610 and an electrode 614. The conductive pad 610 is substantially conductive over the entire processing surface on its upper surface, and is generally a conductive material or, in particular, a polymer matrix or a conductive coating fabric in which conductive particles are dispersed. (I.e., the conductive element is integrated and dispersed with or provided with the material comprising the planarizing surface). The conductive pad 610, the insertion pad 612, and the electrode 614 can be manufactured as a single replaceable assembly. The processing pad assembly 604 is generally permeable or perforated so that electrolyte can pass between the electrode 614 and the top surface 620 of the conductive pad 610. In the embodiment depicted in FIG. 6, the processing pad assembly 604 is perforated with apertures 622 to allow electrolyte to flow there between. In one embodiment, the conductive pad 610 is composed of a conductive material disposed on a polymer matrix disposed on a conductive fiber, for example, tin particles in a polymer matrix disposed on a knitted copper-coated polymer. ing. Conductive pad 610 can also be utilized for contact assembly 250 in the embodiment of FIG. 3C.

  [0059] A conductive foil 616 may additionally be disposed between the conductive pad 610 and the subpad 612. The foil 616 is coupled to the power source 242 and can provide a uniform distribution of the voltage applied by the power source 242 across the conductive pad 610. In embodiments that do not include the conductive foil 616, the conductive pad 610 can be coupled directly to the power source 242 via, for example, a terminal integrated with the pad 610. In addition, the pad assembly 604 may include an insert pad 618 that provides physical strength to the overlying conductive pad 610 along with the foil 616. Examples of suitable pad assemblies are described in US patent application Ser. Nos. 10 / 455,941 and 10 / 455,895, which have already been incorporated by reference.

Method for electrolytic treatment of metal and barrier layer
[0060] FIG. 7 depicts one embodiment of a method 700 for electrotreating a substrate having an exposed conductive layer and an underlying barrier layer that can be implemented for the system 100 described above. The conductive layer can be tungsten, copper, a layer having exposed tungsten and copper, or the like. The barrier layer can be ruthenium, tantalum, tantalum nitride, titanium, titanium nitride, or the like. An insulating layer, typically an oxide, is generally below the barrier layer. The method 700 can be implemented for other electrolytic treatment systems. The method 700 is typically stored in the storage device 112 of the controller 108, typically as a software routine. The software routine may be stored in and / or executed by a second CPU (not shown) located remotely from the hardware controlled by the CPU 110. Good.

  [0061] Although the above process of the present invention has been discussed as being implemented as a software routine, some of the method steps disclosed herein may be performed by hardware as well as a software controller. Also good. Thus, the present invention can be implemented in software running on a computer system, in hardware as an application specific integrated circuit or other type of hardware implementation, or in a combination of software and hardware.

  [0062] FIG. 8 depicts a graph 800 illustrating current 802 and voltage 804 traces for one embodiment of an exemplary removal or planarization method discussed below. Amplitude is plotted on the Y-axis 806 and time is plotted on the X-axis 808.

  [0063] The method 700 begins at step 702 by performing a bulk electrochemical process on a conductive layer formed on the substrate 122. In one embodiment, the conductive layer is a layer of tungsten having a thickness of about 6000 to 8000 mm. Step 702 of the bulk process is performed at the first ECMP station 128. Step 702 of the bulk process generally ends when the conductive layer thickness is about 2000 to about 500 mm.

  [0064] Next, a multi-step electrochemical clearance step 704 is performed to remove the remaining tungsten material and expose the underlying barrier layer, which, in one embodiment, includes titanium or Titanium nitride. The clearance step 704 may be performed on the first ECMP station 128 or one of the other ECMP stations 130, 132.

  [0065] Following the clearance step 704, an electrochemical barrier removal step 706 is performed. Typically, the electrochemical barrier removal step 706 is performed on the third ECMP station 132, but may alternatively be performed on one of the other ECMP stations 128, 130.

  [0066] In one embodiment, the bulk processing step 702 moves, in step 712, the substrate 122 held in the planarization head 204 over the processing pad assembly 222 disposed in the first ECMP station 128. Start by letting. The pad assembly of FIGS. 2, 3A, 4A-4C and 5 is utilized in one embodiment, but alternatively using the pad and contact assembly as described in FIGS. 3B, 3C. It is intended to be good. In step 714, the planarization head 204 is lowered toward the platen assembly 222 and the substrate 122 is placed in contact with the top surface of the pad assembly 222. The substrate 122 is pressed against the pad assembly 222 with a force of less than about 2 pounds per square inch (psi). In one embodiment, the force is about 0.3 psi.

  [0067] In step 716, relative motion between the substrate 122 and the processing pad assembly 222 is provided. In one embodiment, the planarizing head 204 is rotated at about 30-60 revolutions per minute while the pad assembly 222 is rotated at about 7-35 revolutions per minute.

  [0068] In step 718, electrolyte is supplied to the processing pad assembly 604 to establish a conductive path through the assembly between the substrate 122 and the electrode 614. The electrolyte typically includes at least one of sulfuric acid, phosphoric acid, and ammonium citrate.

  [0069] In step 720, the power supply 242 provides a bias voltage between the top surface of the pad assembly 222 and the electrode 292. In one embodiment, the voltage is kept at a constant magnitude less than about 3.5 volts. In another embodiment, where copper is the material being processed, the voltage is kept at a constant magnitude of less than about 3.0 volts. One or more contact elements 250 of the pad assembly 222 are in contact with the substrate 122 so that the voltage can be coupled to the substrate. An electrolytic solution that fills the aperture 210 between the electrode 292 and the substrate 122 results in removal of the tungsten material or other conductive film disposed on the substrate by anodic dissolution in step 722. To provide a conductive path between the power source 242 and the substrate 122. The process of step 722 typically has a tungsten removal rate of about 4000 liters / minute. The process of step 722 using the parameters described above for copper processing generally has a copper removal rate of about 6000 K / min.

  [0070] In step 724, the end point of the bulk electrolysis process is determined. The endpoint can be determined using a first measure of processing generated by meter 244. Meter 244 can provide charge, voltage or current information that is utilized to determine the remaining thickness of a conductive material (eg, a tungsten or copper layer) on the substrate. In another embodiment, optical techniques such as an interferometer that utilizes sensor 254 may be utilized. The remaining thickness can be measured or calculated directly by subtracting the amount of material removed from a given original film thickness. In one embodiment, the endpoint is determined by comparing the charge removed from the substrate with a target charge amount for a predetermined area of the substrate. Examples of endpoint technologies that can be used are US patent application Ser. No. 10 / 949,160 filed Sep. 24, 2004, US patent application Ser. No. 10 filed Jan. 22, 2002. / 056,316 and US patent application Ser. No. 10 / 456,851 filed Jun. 6, 2002. Other endpoint techniques that may benefit from the above method described herein will be described later with reference to FIGS.

  [0071] Step 724 is configured to detect the end point of the process prior to the breakthrough of the tungsten layer. In one embodiment, the remaining tungsten layer in step 724 has a thickness of about 500 to about 2000 mm.

  [0072] The clearance processing step 704 begins at step 726 by moving the substrate 122 held in the planarization head 204 over the processing pad assembly 604 disposed in the second ECMP station 130. In step 728, the planarization head 204 is lowered toward the platen assembly 602 and the substrate 122 is placed in contact with the top surface of the pad assembly 604. In one embodiment, the pad assembly of FIG. 6 is utilized, but the pad assembly and contact assembly as described in FIGS. 2, 3A-3C, 4A-4C, and 5 can be substituted. It is intended that it may be used. The substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 psi. In another embodiment, the force is about 0.3 psi or less.

  [0073] In step 729, relative motion between the substrate 122 and the processing pad assembly 222 is provided. In one embodiment, the planarizing head 204 is rotated at about 30-60 revolutions per minute while the pad assembly 222 is rotated at about 7-35 revolutions per minute.

  [0074] In step 730, electrolyte is supplied to the processing pad assembly 604 to establish a conductive path between the substrate 122 and the electrode 614 through the processing pad assembly. The electrolyte component in step 730 is generally the same as the component in step 722.

  [0075] In step 731 of the first clearance process, a first bias voltage is provided between the top surface of the pad assembly 604 and the electrode 614 by the power source 242. The bias voltage, in one embodiment, is maintained at a constant magnitude in the range of about 1.5 to about 2.8 volts for tungsten processing, and in another embodiment for copper processing, Less than 2.8 volts. This potential difference facilitates the electromechanical polishing process by the current flowing through the electrolyte filling the aperture 622 between the electrode 614 and the substrate 122. The process of step 731 generally has a removal rate of about 1500 Å / min for tungsten and about 2000 Å / min for copper.

  [0076] In step 732, the end point of the electrochemical treatment step 731 is determined. The endpoint can be determined using a first measure of processing generated by meter 244 or by sensor 254. In one embodiment, the endpoint is determined by sensing a first discontinuity 810 of the current detected by meter 244. The discontinuity 810 appears when the underlying layer begins to break through a conductive layer (eg, a tungsten layer). Since the underlying layer has a different resistivity than the tungsten layer, the resistance across the processing cell (ie, from the conductive portion of the substrate to the electrode 292) is the exposed area of the underlying layer. Changes as the area of the tungsten layer relative to changes, resulting in a change in current.

  [0077] In response to endpoint detection in step 732, a second clearance process step 734 is performed to remove the remaining tungsten layer. The substrate is pressed against the pad assembly with a pressure less than about 2 psi, and in another embodiment, the substrate is pressed against the pad assembly with a pressure of about 0.3 psi or less. In step 734, a second voltage is provided from power source 242. The second voltage may be the same as or less than the voltage applied in step 730. In one embodiment, the second voltage is about 1.5 to about 2.8 volts. The voltage is kept at a constant magnitude and facilitates the electromechanical polishing process through the electrolyte filling the aperture 622 between the electrode 614 and the substrate 122. The process of step 734 generally has a removal rate of about 500 to about 1200 liters / minute for both the copper and tungsten processes.

  [0078] In step 736, the end point of the second clearance step 734 is determined. The endpoint can be determined using meter 244 or using a second measure of processing provided by sensor 254. In one embodiment, the endpoint is determined by sensing a second discontinuity 812 of the current detected by meter 244. The discontinuity 812 is the percentage of the area during which the underlying layer is fully exposed through the tungsten layer remaining in features (eg, plugs or other structures) formed in the substrate 122. appear.

  [0079] Optionally, a third clearance process step 738 may be performed to remove any remaining debris from the conductive layer. The third clearance process step 738 is typically a timed process and is performed at the same or lower voltage level as compared to the second clearance process step 734. In one embodiment, the third clearance process step 738 (also referred to as overpolishing) has a duration of about 15 seconds to about 30 seconds.

  [0080] The electrochemical barrier removal step 706 includes, in step 740, moving the substrate 122 held in the planarization head 204 over the processing pad assembly 604 disposed in the third ECMP station 132. Begins. In step 741, the planarization head 204 is lowered toward the platen assembly 602 and the substrate 122 is placed in contact with the top surface of the pad assembly 604. In one embodiment, the pad assembly of FIG. 6 is utilized, but the pad assembly and contact assembly as described in FIGS. 2, 3A-3C, 4A-4C, and 5 are alternatively utilized. It is intended that it may be. The barrier material exposed on the substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 psi, and in one embodiment less than about 0.8 psi.

  [0081] In step 742, relative motion between the substrate 122 and the processing pad assembly 222 is provided. In one embodiment, the planarizing head 204 is rotated at about 30-60 revolutions per minute while the pad assembly 222 is rotated at about 7-35 revolutions per minute.

  [0082] In step 744, electrolyte is supplied to the processing pad assembly 604 to establish a conductive path through the electrolyte between the substrate 122 and the electrode 614. The electrolyte component used for removing the barrier may be different from that for removing tungsten. In one embodiment, the electrolyte component supplied to the third ECMP station 132 includes phosphoric acid or sulfuric acid and a catalyst. The electrolyte can be adapted to prevent or suppress oxide formation on the barrier layer. The catalyst may be Ti or other barrier layer so that the barrier layer can be easily removed and / or dissolved with minimal removal of copper or tungsten, or without removing copper or tungsten. Is selected to react selectively with the complexing agent. The electrolyte component may additionally contain a pH adjusting agent and a chelating agent such as amino acids, organic amines and phthalic acid, or other organic carboxylic acids, picolinic acid or derivatives thereof. In some cases, the electrolytic solution may contain an abrasive. Abrasives may be desirable to remove the underlying oxide layer.

  [0083] In a first barrier process step 746, a bias voltage is provided from the power source 242 between the top surface of the pad assembly 604 and the electrode 614. The voltage is maintained at a constant magnitude in the range of about 1.5 to about 3.0 volts. A conductive path is established through the electrolyte filling the aperture 622 between the electrode 614 and the substrate 122 to facilitate the electromechanical polishing process. The process of step 746 generally has a titanium removal rate of about 500 to about 1000 liters / minute. The removal rates for other barrier materials are similar.

  [0084] In step 748, the end point of the electrolytic treatment step 746 is determined. The end point can be determined by meter 244 or using a first measure of processing provided by sensor 254. The current and voltage traces of the electrochemical barrier removal step 706 are similar to the configuration for traces 802, 804 of FIG. 8, and are therefore omitted for the sake of brevity. In one embodiment, the endpoint of step 748 is determined by sensing a first discontinuity in current detected by meter 244. The first discontinuity appears when the underlying layer (typically an oxide) begins to break through the barrier layer. Since the underlying oxide layer has a different resistivity than the barrier layer, a change in resistance across the processing cell indicates a breakthrough of the barrier layer.

  [0085] In response to endpoint detection in step 748, a second clearance process step 750 is performed to remove the remaining tungsten layer. In step 750, a second voltage is supplied from the power source 242. The second voltage can be less than or equal to the voltage of the first barrier clearance step 746. In one embodiment, the voltage is about 1.5 to about 2.5 volts. The voltage is kept constant and a current is passed through the electrolyte that fills the aperture 622 between the electrode 614 and the substrate 122 to facilitate the electromechanical polishing process. The process of step 750 generally has a removal rate that is less than the first barrier removal step 746, from about 300 to about 600 liters / minute.

  [0086] In step 752, the end point of the electrochemical processing step 750 is determined. The end point can be determined by meter 244 or using a second measure of processing generated by sensor 254. In one embodiment, the endpoint is determined by sensing a second discontinuity in current detected by meter 244. The second discontinuity appears as a percentage of the area during which the oxide layer is completely exposed through the barrier layer remaining in the feature formed in the substrate 122.

  [0087] Optionally, a third clearance process step 754 may be performed to remove remaining debris from the barrier layer. The third clearance process step 754 is typically a timed process and is performed at the same or lower voltage level as compared to the second clearance process step 750. In one embodiment, the third clearance process step 754 (also referred to as overpolishing) has a duration of about 15 seconds to about 30 seconds.

  [0088] FIG. 7 depicts one embodiment of a method 700 for electrolytically treating a conductive material such as copper, tungsten, tantalum, tantalum nitride, titanium, titanium nitride, etc. that can be implemented for the system 100 described above. It is a thing. The method 700 can be implemented for other electrolytic treatment systems. Method 700 is typically stored in storage device 112 of controller 108, typically as a software routine. The software routine may be stored and / or executed by a second CPU (not shown) that is remote from the hardware controlled by the CPU 110.

  [0089] Method 700 begins at step 702 by performing a bulk electrolysis process on the conductive layer, eg, copper formed on substrate 122. In one embodiment, the bulk process step 702 is performed at the first ECMP station 128. Bulk process step 702 generally ends when the conductive layer is about 2000 to about 1000 inches thick.

  [0090] Next, a multi-step electrochemical clearance step 704 is performed to remove the remaining copper material and expose the underlying barrier layer, typically tantalum, tantalum nitride, titanium, titanium nitride, etc. The The clearance step 704 may be performed on the first ECMP station 128 or one of the other ECMP stations 130, 132.

  [0091] Following the clearance step 704, an electrochemical barrier removal step 706 is performed. Typically, the electrochemical barrier removal step 706 is performed on the third ECMP station 132, but may alternatively be performed on one of the other ECMP stations 128, 130.

  [0092] In one embodiment, the bulk processing step 702 moves, in step 712, the substrate 122 held in the planarization head 204 over the processing pad assembly 222 located in the first ECMP station 128. Start by letting. In one embodiment, the pad assembly of FIGS. 2, 3A, 4A-4C, and 5 is utilized, but the pad assembly and contact assembly as described in FIGS. 3B, 3C, and 6 may be used. It is intended that it may be used alternatively. In step 714, the planarization head 204 is lowered toward the platen assembly 230 and the substrate 122 is placed in contact with the top surface of the pad assembly 222. In one embodiment, the substrate 122 is pressed against the pad assembly 222 with a force of less than about 2 psi.

  [0093] In step 716, relative motion between the substrate 122 and the processing pad assembly 222 is provided. In one embodiment, the planarizing head 204 is rotated at less than about 50 revolutions per minute while the pad assembly 222 is rotated at least at about 50 revolutions per minute.

  [0094] In step 718, electrolyte is supplied to the processing pad assembly 222 and a conductive path is established between the substrate 122 and the electrode 222 through the electrolyte. In step 719, current is provided from the power source 242 and flows between the top surface of the pad assembly 222 and the electrode 294. In one embodiment, the current is kept at a constant magnitude in the range of about 4 to about 5 amps. Steps 716, 718, and 719 are performed substantially simultaneously.

  [0095] In embodiments where tungsten is processed, the current is about three times that used in copper processing to achieve the same removal rate. For example, step 719 can provide about 12 to about 15 amps to remove the tungsten conductive layer.

  [0096] The top surface of the pad assembly 222 is in contact with the substrate 122 so that the current can be coupled to the substrate. The electrolyte filling the aperture 210 between the electrode 292 and the substrate 122 provided a conductive path between the power source 242 and the substrate 122 and was placed on the surface of the substrate 122 by anodic dissolution in step 720. Facilitates an electromechanical polishing process that results in the removal of conductive materials such as copper. The process of step 720 generally has a removal rate of about 6000 K / min.

  [0097] At step 722, the endpoint of the bulk electrolysis process is determined. The endpoint can be determined using a first measure of processing generated by meter 244. Meter 244 can provide charge, voltage, or current information that is utilized to determine the remaining thickness of conductive material (eg, a copper layer) on the substrate. In another embodiment, interferometric technology that utilizes sensor 254 may be utilized. The remaining thickness can be measured or calculated directly by subtracting the amount of material removed from a given original film thickness. In one embodiment, the endpoint is determined by comparing the charge removed from the substrate with a target charge amount for a predetermined area of the substrate. Examples of endpoint technologies that can be used are US patent application Ser. No. 10 / 056,316 filed Jan. 22, 2002 and No. 10/456 filed Jun. 6, 2002. , 851 specification.

  [0098] Step 722 is configured to detect the end point of the process prior to the breakthrough of the copper layer. In one embodiment, the remaining copper layer in step 722 has a thickness of about 1000 to about 2000 mm.

  [0099] One embodiment of the clearance processing step 704 will now be discussed with additional reference to the graph 800 of the current and voltage traces 802, 804 depicted in FIG. Amplitude is plotted on the y-axis 806 and time is plotted on the x-axis 808.

  [00100] The clearance processing step 704 begins at step 724 by moving the substrate 122 held in the planarization head 204 over a processing pad assembly 604 disposed in the second ECMP station 130. In step 726, the planarization head 204 is lowered toward the platen assembly 602 and the substrate 122 is placed in contact with the top surface of the pad assembly 604. In one embodiment, the pad assembly of FIG. 6 is utilized, but the pad assembly and contact assembly as described in FIGS. 2, 3A-3C, 4A-4C, and 5 can be substituted. It is intended that it may be used. In one embodiment, the substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 psi. In step 728, electrolyte is supplied to the processing pad assembly 604 to establish a conductive path through the electrolyte between the substrate 122 and the electrode 614.

  [00101] In a first clearance process step 730, a first current is provided from the power source 242 and flows between the top surface of the pad assembly 604 and the electrode 614. In one embodiment, the current (illustrated by current trace 802) is maintained at a constant magnitude in the range of about 5 to about 4 amps and fills the aperture 622 between the electrode 614 and the substrate 122. Accelerates the electromechanical polishing process through the liquid. The process of step 730 generally has a removal rate similar to that of step 722.

  [00102] In step 732, the end point of the electrolysis process step 730 is determined. The endpoint can be determined using a first measure of processing generated by meter 244 or by sensor 254. In one embodiment, the endpoint is determined by sensing a first discontinuity 810 of the voltage detected by meter 244. The first discontinuity 810 appears when the underlying layer begins to break through a conductive layer (eg, a copper layer). Since the underlying layer has a specific resistance different from that of the copper layer, the resistance across the processing cell (ie, from the conductive portion of the substrate to the electrode 292) is exposed to the underlying layer. It changes as the area of the copper layer relative to the area changes.

  [00103] Utilizing a current (or voltage) for endpoint detection removes tungsten because the close refractive properties between the tungsten material and the underlying titanium nitride material make conventional optical sensing difficult. Particularly useful in the process.

  [00104] In response to endpoint detection in step 732, a second clearance process step 734 is performed to remove the remaining copper layer. In step 734, a second current is provided from power source 242. The current is kept at a constant magnitude less than the current in step 730 and facilitates the electromechanical polishing process through the electrolyte filling the aperture 620 between the electrode 614 and the substrate 122. For example, the current can be provided in the range of about 1.5 to about 4.5 amps. The process of step 734 generally has a removal rate of about 500 to about 1500 liters / minute. In a tungsten process, the current can be about 4.5 to about 13.5 amps to obtain a removal rate of 500 to 2000 liters / minute.

  [00105] In step 736, the end point of the electrolysis process step 734 is determined. The endpoint can be determined using a second measure of processing generated by meter 244 or by sensor 254. In one embodiment, the endpoint is determined by sensing a second discontinuity 812 in the voltage detected by meter 244. The discontinuity 812 appears when the underlying barrier layer is fully exposed and the copper layer substantially remaining in features (eg, copper lines and vias) formed in the substrate 122 is removed.

  [00106] Optionally, a third clearance process step 738 may be performed to remove any remaining debris from the conductive layer. The third clearance process step 738 is typically a timed process and is performed at the same or lower current level as compared to the second clearance process step 732. In one embodiment, the third clearance process step 738 (also referred to as overpolishing) has a duration of about 15 to about 30 seconds. During step 738, the current may be reduced below the current level for previous processing steps, for example, 0.5-3 amps.

  [00107] The electrochemical barrier removal step 706 includes, in step 740, moving the substrate 122 held in the planarization head 204 over a processing pad assembly 604 disposed in the third ECMP station 132. Begins. In step 742, the planarizing head 204 is lowered toward the platen assembly 602 and the substrate 122 is placed in contact with the top surface of the pad assembly 604. In one embodiment, the pad assembly of FIG. 6 is utilized, but the pad assembly and contact assembly as described in FIGS. 2, 3A-3C, 4A-4C, and 5 can be substituted. It is intended that it may be used. In one embodiment, the substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 psi. In step 744, electrolyte is supplied to the processing pad assembly 604 to establish a conductive path through the electrolyte between the substrate 122 and the electrode 614. The electrolytic solution used for removing the barrier may be different from the electrolytic solution used for removing copper.

  [00108] In one embodiment, the electrolyte component supplied to the third ECMP station 132 includes phosphoric acid or sulfuric acid and a catalyst. The electrolyte can be adapted to prevent or inhibit the formation of oxides on the barrier layer. The catalyst may be Ti or other barrier layer so that the barrier layer can be easily removed and / or dissolved with minimal or no copper or tungsten removal. Is selected to react selectively with the complexing agent. The electrolyte component may additionally contain pH adjusters and chelating agents such as amino acids, organic amines and phthalic acids, or other organic carboxylic acids, picolinic acids or derivatives thereof. In some cases, the electrolytic solution may contain an abrasive. Abrasives may be desirable to remove the underlying oxide layer.

  [00109] In a first barrier process step 746, a first current is provided from the power source 242 and flows between the top surface of the pad assembly 604 and the electrode 614. In one embodiment, the current is maintained at a constant magnitude in the range of about 1.5 to about 6 amperes, and through an electrolyte that fills the aperture 620 between the electrode 614 and the substrate 122, and electromechanical polishing. Promote the process. The process of step 746 has a removal rate of about 500-2000 kg / min.

  [00110] In step 748, the end point of the electrolysis process 746 is determined. The endpoint can be determined using a first measure of processing provided by meter 244 or by sensor 254. The current and voltage traces of the electrolytic barrier removal step 706 are similar to the traces depicted in FIG. 8, and are therefore omitted for the sake of brevity. In one embodiment, the endpoint of step 748 is determined by sensing a first discontinuity in the voltage detected by meter 244. The first discontinuity appears when the underlying layer (typically an oxide) begins to break through the barrier layer. Since the underlying oxide layer has a different resistivity than the barrier layer, a change in resistance across the processing cell indicates a breakthrough of the barrier layer.

  [00111] In response to endpoint detection in step 748, a second clearance process step 750 is performed to remove the remaining copper layer. In step 748, a second current is provided from the power source 242. The current is kept at a constant magnitude less than the current in step 746 and facilitates the electromechanical polishing process through the electrolyte filling the aperture 620 between the electrode 614 and the substrate 122. For example, in one embodiment, the current can be provided in the range of about 3.5 to about 2.5 amps. The process of step 748 generally has a removal rate of about 1000 liters / minute.

  [00112] In step 752, the end point of the electrolysis process step 750 is determined. The endpoint can be determined using a second measure of processing provided by meter 244 or by sensor 254. In one embodiment, the endpoint is determined by sensing a second discontinuity in the voltage detected by meter 244. The second discontinuity appears when the oxide layer is fully exposed.

  [00113] Optionally, a third clearance process step 754 may be performed to remove remaining debris from the barrier layer. The third clearance process step 754 is typically a timed process and is performed at the same or lower current level as compared to the second clearance process step 746. In one embodiment, the third clearance process step 754 (also referred to as overpolishing) has a duration of about 15 to about 30 seconds.

  [00114] FIG. 9 is a flow diagram of another embodiment of a method 900 for electrochemical processing. Method 900 includes that the electrochemical process is facilitated by a constant voltage provided by power supply 242 as depicted in graph 1000 of current and voltage traces 1002, 1004 shown in FIG. Is substantially the same as the method 800 described above. Amplitude is plotted on the y-axis 1006 and time is plotted on the x-axis 1008.

  [00115] In one embodiment, the method 900 begins at step 902 by performing a bulk electrolysis process on the conductive layer, eg, a copper layer, formed on the substrate 112. Bulk process step 902 generally ends when the conductive layer is about 2000 to about 10000 mm thick.

  [00116] Next, a multi-step electrolytic clearance step 904 is performed to remove the remaining copper material and expose the underlying barrier layer. The clearance step 904 can be performed on the first ECMP station 128 or one of the other ECMP stations 130, 132. Following the clearance step 904, an electrolytic barrier removal step 906 is performed. Typically, the electrolytic barrier removal step 906 is performed on the third ECMP station 132, but may alternatively be performed on one of the other ECMP stations 128, 130.

  [00117] In one embodiment, the bulk processing step 902 is substantially the same as the bulk processing step 702 described above. Bulk processing step 702 utilizes a substantially constant voltage supplied from power source 242 to facilitate the electrochemical process. In one embodiment, the voltage is kept at a constant magnitude in the range of about 1 to about 4 volts. The end point of the bulk electrolysis process is determined by the total charge removed from the conductive layer, as described above, for example, among other methods for endpoint detection. It should be noted that during the first processing step illustrated in the left portion of trace 1002, the current decreases as the conductive layer becomes thinner. This is particularly important when tungsten is removed, so the slope of the trace can be used to determine the removal rate or the remaining thickness of the conductive layer. Thickness vs. current change information can be empirically determined or calculated and stored in a database accessible to the controller 108 used for endpoint detection, removal pro application control or other process control.

  [00118] Next, a clearance processing step 904 is performed. The clearance processing step 904 is the same as step 904 described above except that the electrolysis process is accelerated at a constant voltage. In one embodiment, the voltage is constant for both bulk processing step 902 and clearance processing step 904. In another embodiment, the voltage that facilitates clearance processing step 904 may be less than the previous processing step.

  [00119] The first endpoint of process step 904 is ascertained by detecting a first discontinuity 1010 in current trace 1002 monitored by meter 244. The first endpoint may alternatively be determined by other methods. Detection of the first discontinuity 1010 represents a breakthrough of the copper layer.

  [00120] The second endpoint of process step 904 is ascertained by detecting a second discontinuity 1012 in current trace 1002. The second endpoint may be confirmed by alternative methods. The second discontinuity identifies the clearance of the copper layer. Optionally, a timed over-polishing process may be performed during the clearance processing step 904 after detection of the second end point identified by the second discontinuity 1012.

  [00121] The electrochemical barrier removal step 906 is substantially the same as the barrier removal step 706 described above, except that the electrochemical process is facilitated at a substantially constant voltage. The voltage is generally kept at a substantially constant magnitude that is less than or equal to the voltage utilized in steps 902 and 904. In one embodiment, the voltage is maintained at a substantially constant magnitude that is less than about 3 volts for at least the bulk portion of the barrier removal. The voltage may optionally be reduced relative to the removal portion of the residue of the barrier removal process.

  [00122] Accordingly, the present invention can provide an improved apparatus and method for electropolishing a substrate. The apparatus advantageously facilitates efficient bulk and residual metal and barrier material removal from the substrate using a single tool. Utilizing an electrochemical process for full-sequence metal and barrier removal can provide low erosion and dishing of the conductor and minimize oxide loss during processing. The methods and apparatus described by the teachings herein may be used to deposit material material on a substrate by reversing the polarity of the bias applied to the electrode and substrate. Is intended.

  [00123] While the above is directed to embodiments of the invention, other and additional embodiments of the invention may be devised without departing from the basic scope of the invention. In addition, the scope of the present invention is determined by the appended claims.

It is a top view of an electromechanical polishing system. 2 is a cross-sectional view of one embodiment of a first electromechanical polishing (ECMP) station of the system of FIG. FIG. 3 is a partial cross-sectional view of a bulk ECMP station via two contact assemblies. FIG. 6 is a cross-sectional view of an alternative embodiment of a contact assembly. FIG. 6 is a cross-sectional view of an alternative embodiment of a contact assembly. It is sectional drawing of a plug. It is sectional drawing of a plug. 2 is a side view, exploded view and cross-sectional view of one embodiment of a contact assembly. FIG. It is one Embodiment of a contact body. FIG. 6 is a perspective view of another embodiment of another ECMP station. 1 is a flow diagram of one embodiment of a method for electrolytically treating a conductive material and a barrier material. 1 is a flow diagram of one embodiment of a method for electrolytically treating a conductive material and a barrier material. 1 is a flow diagram of one embodiment of a method for electrolytically treating a conductive material and a barrier material. FIG. 6 depicts a graph illustrating current and voltage trajectories versus time for one embodiment of an exemplary electrolytic treatment method. 1 is a flow diagram of one embodiment of a method for electrolytically treating a conductive material. 1 is a flow diagram of one embodiment of a method for electrolytically treating a conductive material. FIG. 4 is a graph of voltage versus current plots for an exemplary electrolytic process. FIG. 6 is a flow diagram of another embodiment of a method for electrolytically treating a conductive material. FIG. 6 is a graph of current and voltage plots for an exemplary electrolytic process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... System, 108 ... Controller, 110 ... CPU, 112 ... Memory | storage device, 128 ... 1st ECMP station, 130 ... 2nd ECMP station, 132 ... 3rd ECMP station, 204 ... Planarization head, 222 ... Processing Pad assembly, 244 ... meter, 254 ... sensor, 810 ... first discontinuity, 812 ... second discontinuity.

Claims (38)

A method for electrolytically treating a substrate,
Establishing a conductive path between the exposed layer of barrier material on the substrate and the electrode via an electrolyte;
Pressing the substrate against the processing pad assembly with a force of less than about 2 psi;
Providing movement between the substrate and a pad assembly in contact with the substrate;
Electrochemically removing a portion of the exposed layer during a first electrochemical processing step in a barrier processing station;
A method comprising: The first electrochemical treatment step further comprises:
Detecting an end point of the first electrochemical treatment process at or immediately before the breakthrough of the exposed layer made of a barrier material;
Electrochemically treating the exposed layer of the barrier material in a second electrochemical treatment step in the barrier treatment station;
Detecting an end point of the second electrochemical treatment step;
A method comprising: Establishing the conductive path comprises:
The method of claim 1, further comprising flowing an electrolyte from below the electrode in contact with the substrate through the processing pad assembly. The second electrochemical treatment step comprises:
Detecting a first end point;
Electrolytically treating the substrate at a slower rate;
Detecting a second endpoint representative of the remaining barrier material removed from the substrate;
The method of claim 2, further comprising: Detecting the first end point comprises:
The method of claim 4, further comprising detecting a first discontinuity in current flowing between the substrate and the electrode. Detecting the second end point comprises:
The method of claim 5, further comprising detecting a second discontinuity in current flowing between the substrate and the electrode.   The method of claim 1, wherein the electrolyte further comprises a catalyst and at least one of sulfuric acid, phosphoric acid, amino acid, organic amine, phthalic acid, organic coalic acid, or picolinic acid or derivatives thereof.   The method of claim 1, further comprising electrochemically removing a conductive layer disposed over the barrier layer in the processing system.   The method of claim 1, wherein the barrier material is at least one of ruthenium, titanium, titanium nitride, tantalum, and tantalum nitride. A method of electrochemically treating a substrate having an exposed conductive layer and an underlying barrier layer,
Establishing a conductive path through the electrolyte between the exposed layer of conductive material on the substrate and an electrode, wherein the conductive material is copper or tungsten;
Electrochemically removing a portion of the exposed layer in a first processing station during a first electrochemical processing step;
Transferring the substrate to a barrier removal station;
Pressing the substrate against a processing pad assembly disposed in the barrier removal station with a force of less than about 2 psi;
Establishing a conductive path through the electrolyte between the barrier layer and the electrode;
Electrochemically treating the barrier layer;
A method comprising: Detecting an end point of the first electrochemical treatment process at or immediately before the breakthrough of the exposed layer of the conductive material;
Electrochemically treating the exposed layer of the conductive material in a second electrochemical treatment step;
Detecting an end point of the second electrochemical treatment step;
The method of claim 10, further comprising: The barrier processing step further includes
Detecting an end point of the first electrochemical treatment step at or immediately before the breakthrough of the exposed layer of the barrier material;
Electrochemically treating the exposed layer of the barrier material in a second electrochemical treatment step in the barrier treatment station;
Detecting an end point of the second electrochemical treatment step;
The method of claim 10, comprising: The second electrochemical treatment step further comprises:
The method of claim 12, further comprising overpolishing the substrate after detecting the second endpoint. Detecting the first end point further comprises:
The method of claim 12, comprising detecting a first discontinuity in current flowing between the substrate and the electrode. Detecting the second end point further comprises:
The method of claim 14, comprising detecting a second discontinuity in current flowing between the substrate and the electrode.   The method of claim 10, wherein the electrolyte in the barrier removal station further comprises a catalyst and at least one of sulfuric acid or phosphoric acid.   The method of claim 16, wherein the electrolyte in the first processing station has a different component than the electrolyte in the first processing station. A method for electrolytically treating a substrate,
Establishing a conductive path through the electrolyte between the exposed layer of barrier material on the substrate and the electrode;
Electrochemically removing a portion of the exposed layer in a barrier processing station during a first electrochemical processing step;
Detecting an end point of the first electrochemical treatment step at or immediately before the breakthrough of the exposed layer of the barrier material;
Electrochemically processing the exposed layer of the barrier material in a second electrochemical processing step in the barrier processing station;
Detecting an end point of the second electrochemical treatment step;
A method comprising: Contacting a barrier material on the substrate to a processing pad assembly;
Moving the substrate relative to the pad assembly in a polishing motion;
The method of claim 18 comprising: The second electrochemical treatment step further comprises:
Detecting a first end point;
Processing the substrate at a slower rate;
Detecting a second endpoint representative of the remaining barrier material removed from the substrate;
The method of claim 18 comprising: Detecting the first end point further comprises:
Detecting a first discontinuity in the potential difference between the substrate and the electrode, wherein the step of detecting the second end point further detects a second discontinuity in the potential difference between the substrate and the electrode. 21. The method of claim 20, comprising the step of: Detecting the first end point further comprises:
21. The method of claim 20, comprising detecting a first discontinuity in current flowing between the substrate and the electrode. Detecting the second end point further comprises:
Detecting a second discontinuity in current flowing between the substrate and the electrode;
23. The method of claim 22, comprising.   The method of claim 18, further comprising electrochemically removing a conductive layer disposed on the barrier layer in the processing system.   The method of claim 18, further comprising determining a remaining thickness of the barrier layer from a change in current between the substrate and the electrode. A method of electrochemically treating a substrate having an exposed conductive layer and an underlying barrier layer,
Establishing a conductive path through the electrolyte between the exposed layer of conductive material on the substrate and an electrode;
Electrochemically removing a portion of the exposed layer in a first processing station during a first electrochemical processing step;
Detecting an end point of the first electrochemical treatment process at or immediately before the breakthrough of the exposed layer of the conductive material;
Electrochemically treating the exposed layer of the conductive material in a second electrochemical treatment step;
Detecting an end point of the second electrochemical treatment step;
Transferring the substrate to a barrier removal station;
Electrochemically treating the barrier layer;
A method comprising: The first electrochemical treatment step is performed in the first treatment station;
27. The method of claim 26, wherein the substrate is transferred to a second processing station where the second electrochemical processing step is performed. The second electrochemical treatment step further comprises:
Detecting a first end point;
Processing the substrate at a slower rate;
Detecting a second endpoint representing the remaining conductive material removed from the substrate;
28. The method of claim 27, comprising: Detecting the first end point further comprises:
Detecting a first discontinuity in potential difference between the substrate and the electrode;
Detecting a second discontinuity in potential difference between the substrate and the electrode;
30. The method of claim 28, comprising: Detecting the first end point further comprises:
Detecting a first discontinuity in current flowing between the substrate and the electrode;
Detecting a second discontinuity in current flowing between the substrate and the electrode;
30. The method of claim 28, comprising: The barrier electrochemical treatment step further includes
Detecting a first end point;
Processing the substrate at a slower rate;
Detecting a second endpoint representative of the barrier material removed from the substrate;
27. The method of claim 26, comprising: Detecting the first end point further comprises:
Detecting a first discontinuity in potential difference between the substrate and the electrode;
Detecting a second discontinuity in potential difference between the substrate and the electrode;
32. The method of claim 31, comprising: Detecting the first end point further comprises:
Detecting a first discontinuity in current flowing between the substrate and the electrode;
Detecting a second discontinuity in current flowing between the substrate and the electrode;
32. The method of claim 31, comprising:   27. The method of claim 26, further comprising determining a thickness of the conductive material from a change in current. A method of electrochemically treating a substrate having an exposed conductive layer and an underlying barrier layer,
Placing the substrate on a processing pad assembly in a first processing station of a processing system;
Establishing a conductive path through the electrolyte between the exposed layer of conductive material on the substrate and the electrode;
Providing a polishing motion between the processing pad assembly and the substrate in contact with the processing pad assembly;
Electrochemically removing a portion of the exposed layer in a first electrochemical processing step in the first processing station;
Detecting an end point of the first electrochemical treatment process at or immediately before the breakthrough of the exposed layer of the conductive material;
Electrochemically treating the exposed layer of the conductive material in a second electrochemical treatment step;
Detecting an end point of the second electrochemical treatment step;
Transferring the substrate to a barrier removal station;
Establishing a conductive path through the electrolyte between the barrier layer and the electrode in the barrier removal station;
Electrochemically removing portions of the barrier layer during a first electrolytic barrier treatment step in a barrier treatment station;
Detecting an end point of the first electrolytic barrier treatment step at the time of or just before the breakthrough of the barrier material;
Electrochemically processing the barrier material in a second electrochemical barrier processing step within the barrier processing station;
Detecting an end point of the second electrochemical treatment step;
A method comprising: Detecting at least two end points of the barrier processing step and the conductive material processing step;
36. The method of claim 35, comprising detecting a discontinuity in potential difference between the substrate and the electrode. Detecting at least two end points of the barrier treatment step and the copper treatment step;
36. The method of claim 35, comprising detecting a current discontinuity measured between the substrate and the electrode.   36. The method of claim 35, further comprising determining a remaining thickness of the conductive material from a change in current.

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