KR20070046187A - Full sequence metal and barrier layer electrochemical mechanical processing - Google Patents

Abstract

Methods of electrochemically processing metals and barrier materials are provided. In one embodiment, a method of electrochemically processing a substrate forms an electrically-conductive path through an electrolyte between an electrode and an exposed layer of barrier material on the substrate, the substrate being less than about 2 psi relative to the processing pad assembly. Pressurizing with force, providing motion between the substrate and the pad assembly in contact with each other, and electrochemically removing a portion of the exposed layer during a first electrochemical processing step at the barrier processing station. do.

Description

FULL SEQUENCE METAL AND BARRIER LAYER ELECTROCHEMICAL MECHANICAL PROCESSING

Embodiments of the present invention relate generally to a method of electrochemical processing.

Electrochemical mechanical planarization (ECMP) is a technique used to remove conductive material from a substrate surface by electrochemical dissolution while simultaneously polishing the substrate with less mechanical wear compared to conventional planarization processes. In general, ECMP systems can also be applied to deposit conductive materials on a substrate by reversing the polarity of the bias. Electrochemical dissolution is accomplished by applying a bias between the cathode and the substrate surface to remove the conductive material from the substrate surface to the surrounding electrolyte. Typically, a bias is applied to the substrate surface by the conductive polishing material on which the processing substrate is placed. The mechanical component of the polishing process is carried out by providing relative motion between the substrate and the conductive polishing material, which relative motion facilitates the removal of the conductive material from the substrate.

In many conventional systems, conventional chemical mechanical processing for barrier removal is followed by ECMP of the conductive film. Such dichotomous processing (eg, ECMP and CMP in a single system) requires a variety of equipment and process consumables, resulting in high costs. In addition, since most ECMP processes use a small contact pressure between the substrate being processed and the processing surface, the head used for holding the substrate during processing is typically robust when used in conventional CMP processes with large contact pressures. ) Does not provide processing performance, which results in high wear of the conductive material in trenches or other features. Since the removal rate of low pressure conventional CMP barrier layer processing is generally less than about 100 kW / min, conventional CMP processing of barrier materials using low pressure is not suitable for mass production. Thus, it would be desirable to have a system that can be used to remove barrier materials such as ruthenium, tantalum, tantalum nitride, titanium, titanium nitride, and the like through an electrochemical process.

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

In general, embodiments of the present invention provide a method of processing a barrier and metal disposed on a substrate in an electrochemical planarization system. Methods and apparatus are provided for electrochemically processing metal and barrier materials. In one embodiment, a method of electrochemically processing a substrate comprises establishing an electro-conductive path through an electrolyte between an electrode and an exposed layer of barrier material on the substrate, the substrate having a force of less than about 2 psi relative to the processing pad assembly. Pressing to, providing motion between the substrate and the pad assembly in contact with each other, and electrochemically removing a portion of the exposed layer during the first electrochemical processing step at the barrier processing station.

In another embodiment, a method of electrochemically processing a substrate may include removing a conductive layer having a barrier layer underneath at a first processing station of the system, and using a low contact pressure on the processing pad of the substrate. 2 electrochemically removing the barrier layer at the processing station. The system may include a processing station located between the first and second processing stations and for removing residues of the conductive layer using a multi-step removal process.

In another embodiment, the method establishes an electro-conductive path through an electrolyte between the electrode and the exposed layer of barrier material on the substrate, electrochemically removing a portion of the exposed layer during the first electrochemical processing at the barrier processing station. Removing the barrier material, detecting an endpoint of the first electrochemical processing step at or before breakthrough of the exposed layer of barrier material, and during the second electrochemical processing step at the barrier processing station. Electrochemically processing the exposed layer of, and detecting an endpoint of the second electrochemical processing step.

In another embodiment, a method of electrochemically processing a substrate includes removing a conductive layer with a barrier layer disposed underneath at a first processing station of the system, and electrochemically removing the barrier layer at a second processing station of the system. It includes a step. The system may include a processing station located between the first and second processing stations and for removing residues of the conductive layer using a multi-step removal process.

BRIEF DESCRIPTION OF THE DRAWINGS In order to achieve the above-described embodiments of the present invention and to understand in more detail, the present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings. It is to be understood, however, that the appended drawings illustrate only typical embodiments of the invention, and thus, do not limit the scope of the invention, and other equivalent, effective embodiments are possible.

1 is a plan view of an electrochemical mechanical planarization system.

2 is a cross-sectional view of one embodiment of a first electrochemical mechanical planarization (ECMP) station of the system of FIG. 1.

3A is a partial cross-sectional view of a bulk ECMP station through two contact assemblies.

3B and 3C are cross-sectional views of another embodiment of a contact assembly.

3D and 3E are cross-sectional views of the plug.

4A and 4B are side and exploded views of one embodiment of a contact assembly.

5 is a perspective view illustrating one embodiment of a contact element.

6 is a perspective view of another embodiment of another ECMP station.

7 is a flow diagram of one embodiment of a method for electroprocessing conductive material and barrier material.

FIG. 8 is a graph showing time and current traces and voltage traces in one embodiment of an exemplary electrical processing method. FIG.

9 is a flow diagram of one embodiment of a method for electroprocessing a conductive material.

10 is a graph illustrating voltage and current plots for an exemplary electrical process.

11 is a flow chart of another embodiment of a method for electroprocessing a conductive material.

12 is a graph illustrating current and voltage plots for an exemplary electrical process.

For ease of understanding, like reference numerals designate like elements throughout the drawings. Without further explanation, it will be appreciated that the components of one embodiment may be advantageously used in other embodiments.

Embodiments of a method and system for removing conductive material and barrier material from a substrate are provided. While the embodiments described below focus primarily on removing material from the substrate, for example, planarization, the disclosure disclosed herein is directed to reversing the substrate by inverting the polarity of the electrical bias applied between the electrode and the substrate of the system. It will be appreciated that it can also be used for electroplating.

1 is a plan view of one embodiment of a planarization system 100 having an apparatus for electrochemically processing a substrate. In general, such exemplary system 100 includes a factory interface 102, a loading robot 104, and a planarization module 106. The loading robot 104 is disposed adjacent to the factory interface 102 and the flattening module 106 to assist transfer of the substrate 122 therebetween.

A control unit 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 memory 112, and support circuits 114. The controller 108 is connected to various components of the system 100 to help control the planarization, cleaning and transfer processes, for example.

In general, factory interface 102 includes a cleaning module 116 and one or more wafer cassettes 118. The interface robot 120 is used to transfer the substrate 122 between the wafer cassette 118, the cleaning module 116, and the input module 124. The input module 124 is positioned to help transfer the substrate between the flattening module 106 and the factory interface 102, for example by a gripper such as a vacuum gripper or mechanical clamp.

The planarization module 106 includes at least a first electrochemical mechanical planarization (ECMP) station 128 disposed in the environment controlled enclosure 188. Examples of planarization module 106 that may be advantageously employed in the present invention include MIRRA ^® , MIRRA MESA ^TM , REFLEXION ^® , REFLEXION ^® LK, and the like provided by Applied Materials, Inc., Santa Clara, CA. REFLEXION LK Ecmp ^™ chemical mechanical planarization system. Other planarization modules utilizing processing pads, planarization webs, or combinations thereof, and other planarization modules that move the substrate relative to the planarization surface relative to the planarization surface in a rotational, linear, or other planar motion direction are advantageous in the present invention. May be applied.

In the embodiment shown in FIG. 1, the planarization module 106 includes a first ECMP station 128, a second ECMP station 130, and a third ECMP station 132. Bulk removal of the conductive material disposed on the substrate 122 will be performed through an electrochemical dissolution process at the first ECMP station 128. After removing the bulk material at the first ECMP station 128, the remaining conductive material is removed from the substrate through a multi-step electrochemical mechanical process at the second ECMP station 130, wherein some of the multi-step process removes the remaining conductive material. It is configured to. One or more ECMP stations may be used to perform a bulk removal process at another station followed by a multi-step removal process. Alternatively, bulk and multistage conductive material removal may be performed in a single station using respective first and second ECMP stations 128 and 130. All ECMP stations (eg, three stations of module 106 shown in FIG. 1) may be configured to process the conductive layer in a two step removal process.

Exemplary planarization module 106 also includes a transport station 136 and a carousel 134 disposed on the top or first side 138 of the machine base 140. In one embodiment, the 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 the substrates 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. A transfer robot 146 is used to transfer the substrate between the buffer stations 142, 144 and the load cup assembly 148.

In one embodiment, the transfer robot 146 includes two gripper assemblies, each gripper assembly having a pneumatic gripper finger that holds the substrate using 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 while simultaneously transferring the processed substrate from the load cup assembly 148 to the output buffer station 144. Examples of transfer stations that can preferably be used are described in US Pat. No. 6,156,124, filed December 5, 2000 to Tobin.

The cursor cell 134 is disposed at the center on the base 140. Typically, the curler cell 134 includes a plurality of arms 150, each arm supporting the flattening head assembly 152. Two of the arms 150 shown in FIG. 1 are shown in dashed lines, so that the flattening surface of the first ECMP station 128 and the transfer station 136 can be seen. The cursor cell 134 is indexable such that the flattening head assemblies 152 may be moved between the flattening stations 128, 130, 132 and the transfer station 136. One cursor cell that can be used advantageously is disclosed in US Pat. No. 5,804,507 to Perlov et al. On September 8, 1998.

Conditioning device 182 is disposed on base 140 adjacent each flattening station 128, 130, 132. Conditioning device 182 periodically condition the planarization material disposed at stations 128, 130, and 132 to maintain uniform planarization results.

2 is a cross-sectional view showing one of the flattening head assemblies 152 located on one embodiment of the first ECMP station 128. The second and third ECMP stations 130 and 132 may be similarly configured. Generally, the flattening head assembly 152 includes a drive system 202 coupled to the flattening head 204. The drive system 202 generally provides at least rotational movement with respect to the flattening head 204. The planarization head 204 is directed towards the first ECMP station 128 such that the substrate 122 held in the planarization head 204 is disposed against the planarization surface 126 of the first ECMP station 128 during processing. Can be additionally operated. The drive system 202 is coupled to the control unit 108, which provides a signal to the drive system 202 to control the speed and direction of rotation of the flattening head 204.

In one embodiment, the planarization head may be a TITAN HEAD ^™ or TITAN PROFILER ^™ wafer carrier manufactured by Applied Materials, Inc. Generally, the planarization head 204 includes a housing 214 and a retaining ring 224, which form a central recess in which the substrate 122 is held. Retaining ring 224 surrounds substrate 122 located within planarizing head 204 to prevent the substrate from slipping out from below planarizing head 204 during processing. The retaining ring 224 may be made of a plastic material such as PPS, PEEK, or the like, or a conductive material such as stainless steel, Cu, Au, Pd, or the like, or a combination thereof. It may also be possible to electrically bias the conductive retaining ring 224 to control the electric field during ECMP. Conductive or biased retaining ring 224 tends to slow the polishing rate near the edge of the substrate. Other planarization heads may be used.

Generally, the first ECMP station 128 includes a platen assembly 230 rotatably disposed on the base 140. The platen assembly 230 is supported above the base 140 by a bearing 238 so that the platen assembly 230 can be rotated relative to the base 140. The area of the base 140 surrounded by the bearing 238 is open and provides conduits for electrical, mechanical, pneumatic, control signals and connections that are in communication with the platen assembly 230.

Conventional bearings, rotary unions and slip rings, collectively referred to as rotary coupler 276, are provided to couple electrical, mechanical, pneumatic, control signals and connections between base 140 and rotary platen assembly 230. have. Typically, the platen assembly 230 is connected to a motor 232 that provides rotational motion to the platen assembly 230. The motor 232 is connected to a controller 108 that provides a signal to control the rotational speed and direction of the platen assembly 230.

Top surface 260 of platen assembly 230 supports processing pad assembly 222. The processing pad assembly 222 is held relative to the platen assembly 230 by magnetic attraction, vacuum, clamps, adhesion, and the like.

Plenum 206 is formed in platen assembly 230 to help distribute the electrolyte evenly with respect to planarization surface 126. Multiple passageways, as described in more detail below, are formed in the platen assembly 230 such that electrolyte provided from the electrolyte source 248 to the plenum 206 is uniform through the platen assembly 230 during processing. Flow rate and uniform contact with the substrate 122. Various electrolyte compositions may be provided during different processing steps or at different ECMP stations 128, 130, 132.

Processing pad assembly 222 includes an electrode 292 and at least planarization portion 290. Typically, electrode 292 is made of a conductive material such as stainless steel, copper, aluminum, gold, silver and tungsten. Electrode 292 may be solid, electrolyte impermeable, electrolyte permeable or perforated. One or more contact assemblies 250 are configured to extend above the processing pad assembly 222 and to electrically connect the substrate being processed on the processing pad assembly 222 to a power source 242. In addition, an electrode 292 is connected to the power source 242 such that an electrical potential is formed between the substrate and the electrode 292.

An instrument 244 is provided for detecting a metric indicative of an electrochemical process. Meter 244 can be located or coupled between power source 242 and one or more electrodes 292 or contact assembly 250. In addition, the meter 244 may be integrally configured with the power source 242. In one embodiment, the meter 244 may be configured to provide the controller 108 with a metering index of processing, such as charge, current, and / or voltage. Using this measurement, control 108 may adjust processing parameters in-situ or facilitate endpoint or other process stage detection.

A window 246 is provided through the pad assembly 222 and / or the platen assembly 230, and configured to allow a sensor 254 located below the pad assembly 222 to sense a measurement index of the polishing operation. Can be. For example, the sensor 254 may be a sensor such as an eddy current sensor or an interferometer. The measurements provided by the sensor 254 to the controller 108 provide information that can be used for in-situ processing profile adjustment, endpoint detection or other point detection in the electrochemical process. In one embodiment, the sensor 254 is an interferometer capable of generating a collimating light beam that is delivered to one side of the substrate 122 that is polished during processing. Interference between the reflected signals is indicative of the thickness of the conductive layer of material being processed. One sensor that can be used advantageously is disclosed in US Pat. No. 5,893,796, issued April 13, 1999 to Birang et al., Which is incorporated herein by reference in its entirety.

In general, embodiments of the processing pad assembly 222 suitable for removing conductive material from the substrate 122 will include a planarization surface 126 that is substantially dielectric. Other embodiments of processing pad assembly 222 suitable for removing conductive material from substrate 122 may generally include planarizing surface 126 that is substantially conductive. One or more contact assemblies 250 are provided to connect the substrate to a power source 242 such that the substrate can be biased against the electrode 292 during processing. An opening 210 formed through the planarization layer 290 allows the electrolyte to form a conductive path between the substrate 122 and the electrode 292.

In one embodiment, the planarization portion 29 of the processing pad assembly 222 is a dielectric, such as polyurethane. Examples of processing pad assemblies that can be advantageously applied to the present invention are described in US Patent Application No. 10 / 455,941 ("Conductive Flattening Product for Electrochemical Mechanical Flattening") filed June 6, 2003 by Y. Hu et al. US Patent Application No. 10 / 455,895 ("Conductive Planarization Products for Electrochemical Mechanical Planarization"), filed June 6, 2003 by Hu et al.

3A is a partial cross-sectional view of a first ECMP station 128 through two contact assemblies 250, and FIGS. 4A-4C are side, exploded and cross-sectional views of the contact assembly 250 shown in FIG. 3A. Platen assembly 230 includes one or more contact assemblies 250 protruding from the platen assembly and is coupled to a power source 242 that applies a bias to the surface of substrate 122 during processing. Contact assembly 250 may be coupled to platen assembly 230, processing pad assembly 222, or other separate element. Although two contact assemblies 250 are shown in FIG. 3A, any number of contact assemblies can be used and arranged in any number of configurations relative to the centerline of the platen assembly 230.

In general, contact assembly 250 may be moved to extend at least partially through each opening 368 formed in processing pad assembly 222 and electrically coupled to power source 242 via platen assembly 230. have. The location of contact assembly 250 may be selected to have a predetermined configuration over platen assembly 230. In a predetermined process, individual contact assemblies 250 may be repositioned within other openings 368, and stoppers 392 may be plugged into the openings that do not receive contact assemblies or nozzles 394 (FIG. 3D-). (As shown in 3e), the nozzle allows electrolyte to flow from the plenum 206 to the substrate. One contact assembly that may be advantageously applied to the present invention is disclosed in US patent application Ser. No. 10 / 445,239, filed May 23, 2003 to Butterfield et al.

Although the contact assembly 250 described below in connection with FIG. 3A shows a rolling ball contact, the contact assembly 250 is instead suitable for electrically biasing the substrate 122 during processing. It may also include an assembly or structure having a conductive top layer or surface. For example, as shown in FIG. 3B, the contact assembly 250 may include a pad structure 350 made of a pad material 350 conductive material or a conductive composite and having a top layer 352, wherein Examples of conductive composites include conductor coated fabrics or polymer matrices 354 with conductive particles 356 dispersed therein. Pad structure 350 may include one or more openings 210 formed therethrough for delivering electrolyte to the top surface of the pad assembly. Another example of a suitable contact assembly is disclosed in US patent application Ser. No. 10 / 940,603 filed September 14, 2004 by Mao et al.

In one embodiment, each contact assembly 250 includes a hollow housing 302, an adapter 304, a ball 306, a contact element 314 and a clamp bushing 316. The ball 306 has a conductive outer surface and is movably disposed within the housing 302. The ball 306 is in a first position where at least a portion of the ball 306 extends above the planarization surface 126 and at least in a second position where the ball 306 is substantially flush with the planarization surface 126. Can be located. Ball 306 may only be moved below the planarization surface 126. In general, the ball 306 is suitable for electrically connecting the substrate 122 to the power source 242. As shown in FIG. 3C, multiple balls 306 for biasing the substrate may be disposed in one housing 358.

In general, power supply 242 provides a positive electrical bias for ball 306 during processing. Optionally, between planarization operations of the substrate, the power source 242 may provide a negative bias to the ball 306 to minimize process chemical attack of the ball 306.

The housing 302 is configured to provide a conduit that allows electrolyte to flow from the source 248 to the substrate 122 during processing. The housing 302 is made of a dielectric material compatible with the process chemistry. The seat 326 formed in the housing 302 prevents the ball 306 from escaping from the first end 308 of the housing 302. Optionally, the seat 326 may include one or more grooves 348, which allow fluid to exit the housing 302 between the ball 306 and the seat 326. Maintaining fluid flow through the ball 306 may reduce the tendency of process chemicals to attack the ball 306.

Contact element 314 is coupled between clamp bushing 316 and adapter 304. In general, the contact element 314 is configured to electrically connect the adapter 304 and the ball 306 throughout or substantially throughout the range of ball positions in the housing 302. In one embodiment, contact element 314 is configured in the form of a spring.

In the embodiment shown in FIGS. 3, 4A-4C and 5, the contact element 314 includes an annular base 342 in which a number of flexures 344 extend into a polar array. . Generally, the deformable portion 344 is made of a resilient conductive material suitable for use with process chemicals. In one embodiment, the deformable portion 344 is made of beryllium copper plated with gold.

Referring again to FIGS. 3A and 4A-4B, clamp bushing 316 includes a flared head 424 from which threaded posts 422 extend. Clamp bushing 316 may be made from a dielectric or conductor material, or a combination thereof, and in one embodiment, is made from the same material as housing 302. The flared head 424 holds the deformable portion 344 at an acute angle with respect to the centerline of the contact assembly 250 such that the deformable portion 344 of the contact element 314 is positioned to unfold around the surface of the ball 306. This prevents bending, binding and / or damage to the deformable portion 344 during assembly of the contact assembly 250 and over the range of motion of the ball 306.

The ball 306 may be solid or hollow and is typically made of a conductive material. For example, the ball 306 may be metal; Conductive polymers; Or a polymeric material filled with a conductive material such as metal, conductive carbon, or graphite. Instead, the ball 306 may be formed of a solid or hollow core coated with a conductive material. The core may be non-conductive and may be at least partially coated with conductive covering.

In general, the ball 306 is actuated towards the flattening surface 126 by one of spring force, buoyancy or flow forces. In the embodiment shown in FIG. 3, flow through the adapter 304 and the clamp bushing 316 and the platen assembly 230 from the electrolyte source 248 during processing forces the ball 306 into contact with the substrate.

6 is a cross-sectional view of one embodiment of a second ECMP station 130. The first and third ECMP stations 128, 132 can be configured similarly to each other. Generally, the second ECMP station 130 includes a platen 602 that supports the processing pad assembly 604 as a whole. The platen 602 may be configured similar to the platen assembly 230 described above to deliver electrolyte through the processing pad assembly 604, or the platen 602 may be disposed adjacent to the fluid delivery arm 606. And may supply electrolyte to the planarization surface of the processing pad assembly 604. The platen assembly 602 includes one or more meters 244 or sensors 254 (see FIG. 2) to assist in endpoint detection.

In one embodiment, the processing pad assembly 604 includes an intermediate pad 612 sandwiched between the conductive pad 610 and the electrode 614. Conductive pad 610 is substantially conductive over the upper processing surface and generally is a conductive material or conductive composite (ie, the conductive element comprises or is integrally distributed with the material comprising the planarization surface). For example, the conductive composite includes a conductive coating fabric or a polymer matrix in which conductive particles are dispersed. Conductive pads 610, intermediate pads 612, and electrodes 614 may be made of a single replaceable assembly. In general, the processing pad assembly 604 may be permeable or perforated to allow electrolyte to pass between the top surface 620 of the conductive pad 610 and the electrode 614. In the embodiment shown in FIG. 6, processing pad assembly 604 is perforated by opening 622 to allow electrolyte to pass through. In one embodiment, conductive pad 610 may be comprised of a conductive material disposed on a polymer matrix disposed on conductive fibers, such as tin particles in a polymer matrix disposed on a woven copper coated polymer. Conductive pads 610 may also be used in the contact assembly 250 of the embodiment shown in FIG. 3C.

The conductive foil 616 may be further disposed between the conductive pad 610 and the subpad 612. Foil 616 is connected to power source 242 and distributes the voltage supplied by power source 242 evenly across conductive pad 610. In embodiments that do not include conductive foil 616, conductive pad 610 may be directly connected to power source 242, for example, via a terminal integral with the pad 610. In addition, the pad assembly 604 can include an intermediate pad 618, which, together with the foil 616, provides mechanical strength to the conductive pad 610 on top. Examples of suitable pad assemblies are disclosed in the aforementioned US patent applications 10 / 455,941 and 10 / 455,895.

Metal and Barrier  Floor Electroprocessing  Way

FIG. 7 illustrates an embodiment of a method 700 for electroprocessing a substrate having an exposed conductive layer and a lower barrier layer, which may be implemented on the system 100 described above. The conductive layer may be tungsten, copper, a layer with both exposed tungsten and copper, and the like. The barrier layer may be ruthenium, tantalum, tantalum nitride, titanium, titanium nitride, or the like. A dielectric layer, which is typically an oxide, is generally located below the barrier layer. The method 700 may also be practiced in other electrical processing systems. In general, the method 700 is stored as a software routine in the memory 112 of the controller 108. The software routine may also be stored and / or executed by a second CPU (not shown) located remote from hardware controlled by the CPU 110.

Although the process of the present invention is described as being implemented as a software routine, some steps of the methods described herein may be executed in hardware as well as by software controls. In that case, the invention may be practiced in the form of software executed on a computer system, in hardware or other types of hardware embodiments, such as application specific integrated circuits, or in a combination of software and hardware.

8 shows a graph 800 showing a current trace 802 and a voltage trace 804 over one embodiment of an exemplary removal or planarization method as described below. Sizes are listed on the Y-axis 806 and times are written on the X-axis 808.

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 tungsten layer having a thickness of about 6000-8000 mm 3. In general, bulk process step 702 ends when the thickness of the conductive layer is between about 2000 and about 500 microns.

Next, a multi-step electrochemical cleaning step 704 is performed to remove the remaining tungsten to expose the underlying barrier layer, which in one embodiment is titanium or titanium nitride. The cleaning step 704 may be performed at the first ECMP station 128 or at one of the other ECMP stations 130, 132.

After the cleaning step 704, an electrochemical barrier removal step 706 is performed. Typically, the electrochemical barrier removal step 706 is performed at the third ECMP station 132, but may instead be performed at one of the other ECMP stations 128, 130.

In one embodiment, the bulk processing step 702 is performed by moving the substrate 122 held in the flattening head 204 upwards of the processing pad assembly 222 disposed in the first ECMP station 128. 712). Although the pad assemblies of FIGS. 2, 3A, 4A-4C are used, in one embodiment, the pad and contact assemblies shown in FIGS. 3B-3C may be used instead. In step 714, the flattening head 204 is lowered toward the platen assembly 230 to contact the substrate 122 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.

In step 716, relative motion between the substrate 122 and the processing pad assembly 222 is provided. In one embodiment, the flattening head 204 is rotated at a speed of about 30-60 rpm, and the pad assembly 222 is rotated at a speed of about 7-35 rpm.

In step 718, an electrolyte is supplied to the processing pad assembly 604 to form a conductive path between the substrate 122 and the electrode 614. Typically, the electrolyte comprises one of sulfuric acid, phosphoric acid and ammonium citrate.

At step 720, a power source 242 provides a bias voltage between the electrode 292 and the top surface of the pad assembly 222. In one embodiment, the voltage is maintained at a constant magnitude of less than about 3.5 volts. In another embodiment where the material being processed is copper, the voltage is maintained 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 and allow voltage to be connected. The electrolyte filling the opening 210 between the electrode 292 and the substrate 122 provides a conductive path between the power source 242 and the substrate 122 to drive the electrochemical mechanical planarization process, resulting in such a step. The tungsten material or other conductive film deposited on the substrate is removed by the anodization method at 722. In general, the process of step 722 has a tungsten removal rate of about 4000 kPa / min. The process of step 722 using the aforementioned parameters for copper processing generally has a copper removal rate of about 6000 kW / min.

In step 724, an endpoint of the bulk electrical process is determined. The first processing measure provided by instrument 244 may be used to determine the endpoint. Meter 244 provides charge, voltage or current information used to determine the residual thickness of a conductive material (eg, tungsten or copper layer) on a substrate. In other embodiments, optical techniques such as interferometers using sensors 254 may be used. The residual thickness can be measured directly or can be calculated by subtracting the amount of material removed from the predetermined starting film thickness. In one embodiment, the endpoint can be determined by comparing the charge removed from the substrate to a target charge amount for a predetermined region of the substrate. Examples of endpoint techniques that may be used are described in US Patent No. 10 / 949,160, filed September 24, 2004, US Patent Application No. 10 / 056,316, filed January 22, 2002, and June 6, 2002. US patent application Ser. No. 10 / 456,851, filed with. Other endpoint techniques that may be advantageously applied among the methods described herein are described below with reference to FIGS. 9-12.

Step 724 is configured to detect an endpoint of the process prior to breakthrough of the tungsten layer. In one embodiment, the residual tungsten layer has a thickness of about 500 to about 2000 mm 3 in step 724.

The cleaning 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 flattening head 204 is lowered toward the platen assembly 602 to contact the substrate 122 with the top surface of the pad assembly 604. Although the pad assembly of FIG. 6 has been used, in one embodiment, the pad and contact assemblies shown in FIGS. 2, 3A-3C, 4A-4C and 5 may be used instead. The substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 pounds per square inch (psi). In another embodiment, the force is about 0.3 psi or less.

In step 729, relative motion is provided between the substrate 122 and the processing pad assembly 222. In one embodiment, the flattening head 204 is rotated at a speed of about 30-60 rpm, and the pad assembly 222 is rotated at a speed of about 7-35 rpm.

In step 730, electrolyte is supplied to the processing pad assembly 604 to form a conductive path between the substrate 122 and the electrode 614. Typically, the electrolyte composition in step 730 has the same composition as the electrolyte in step 722.

In a first cleaning process step 731, a first bias voltage is applied between the top surface of the pad assembly 604 and the electrode 614 by the power supply 242. The bias voltage, in one embodiment, remains constant at about 1.5 to about 2.8 volts for tungsten processing, and remains below 2.8 volts when processing copper in other embodiments. The potential deviation allows current to flow through the electrolyte filling the opening 622 between the electrode 614 and the substrate 122 to drive the electrochemical mechanical planarization process. In general, the process of step 731 has a removal rate of about 1500 kW / min for tungsten and about 2000 kW / min for copper.

In step 732, the endpoint of the electrical process step 731 is determined. The endpoint may be determined using the first processing measurements provided by instrument 244 or sensor 254. In one embodiment, the endpoint is determined by detecting a first discontinuity 810 of the current sensed by the meter 244. Discontinuities 810 appear when the underlying layer begins to penetrate through the conductive layer (eg, tungsten layer). Because the lower layer has a different resistance than the tungsten layer, the resistance across the processing cell (ie, from the conductive portion of the substrate to the electrode 292) changes as the area of the tungsten layer with respect to the exposed area of the lower layer changes, Accordingly changes the current.

In response to the endpoint detection at step 732, a second wash process step 734 is performed to remove the residual tungsten layer. The substrate is pressed against the pad assembly at a pressure of less than about 2 psi, and in another embodiment the substrate is pressed against the pad assembly at a pressure of about 0.3 psi or less. In step 734, a second voltage is provided from the power source 242. The second voltage may be equal to 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 maintained at a constant magnitude and flows through the electrolyte filling the opening 622 between the electrode 614 and the substrate 122 to drive the electrochemical mechanical planarization process. In general, the process of step 734 has a removal rate of about 500 to about 1200 milliseconds per minute in both the copper and tungsten processes.

In step 736, the end point of the second wash step 734 is determined. The endpoint may be determined using a second processing measurement provided by instrument 244 or sensor 254. In one embodiment, the endpoint is determined by detecting the second discontinuity 812 of the current sensed by the meter 244. Discontinuities 812 appear when the area ratio between underlying layers is fully exposed through the tungsten layer remaining in features (eg, plugs or other structures) formed in substrate 122.

Optionally, a third cleaning process step 738 may be performed to remove residue chips from the conductive layer. Typically, third wash process step 738 is a timed process and is performed at a voltage level equal to or lower than second wash process step 734. In one embodiment, the third cleaning process step 738 (also referred to as an overpolish step) has a duration of about 15 to about 30 seconds.

The cleaning processing step 706 begins at step 740 by moving the substrate 122 held in the planarization head 204 over the processing pad assembly 604 disposed in the third ECMP station 132. In step 741, the flattening head 204 is lowered toward the platen assembly 602 to contact the substrate 122 with the top surface of the pad assembly 604. Although the pad assembly of FIG. 6 has been used, in one embodiment, the pad and contact assemblies shown in FIGS. 2, 3A-3C, 4A-4C and 5 may be used instead. The substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 psi, and in other embodiments, the force is less than about 0.8 psi.

In step 742, relative motion is provided between the substrate 122 and the processing pad assembly 222. In one embodiment, the flattening head 204 is rotated at a speed of about 30-60 rpm, and the pad assembly 222 is rotated at a speed of about 7-35 rpm.

In step 744, electrolyte is supplied to the processing pad assembly 604 to form a conductive path between the substrate 122 and the electrode 614. The electrolyte composition used for barrier removal will be different from the electrolyte used for tungsten removal. In one embodiment, the electrolyte composition provided at the third ECMP station 132 comprises phosphoric acid or sulfuric acid and a catalyst. The electrolyte can be configured to prevent or inhibit the formation of oxides on the barrier layer. The catalyst is selected to selectively react with complexing agents by activating Ti or other barrier layers, thereby allowing easy removal and / or decomposition of the barrier layer with or without minimal removal of copper or tungsten. have. The electrolyte composition may further comprise detergents such as amino acids, organic amines and phthalic acid or other organic phenols, picolinic acid or derivatives thereof, and pH adjusters. The electrolyte may optionally include abrasive agents. Abrasive agents are preferred for removing some of the underlying oxide layer.

In a first barrier process step 746, a bias voltage is provided from the power source 242 between the pad assembly 604 and the electrode 614. The voltage is kept constant at about 1.5 to about 3.0 volts. A conductive path formed through the electrolyte filling the opening 622 between the electrode 614 and the substrate 122 drives the electrochemical mechanical planarization process. In general, the process of step 746 has a titanium removal rate of about 500 kPa / min to about 1000 kPa / min. Similar to the removal rate for other barrier materials.

In step 748, the end point of the electrical process step 746 is determined. The endpoint may be determined using the first processing measurements provided by instrument 244 or sensor 254. Current and voltage traces of the electrochemical barrier removal step 706 are similar to traces 802 and 804 of FIG. 8 and are therefore omitted for clarity. In one embodiment, an endpoint is determined by detecting a first discontinuity of current sensed by meter 244. The first discontinuity appears when the underlying layer (usually an oxide) begins to penetrate the barrier layer. Since the underlying layer has a different resistance than the barrier layer, a change in resistance across the processing cell indicates penetration of the barrier layer.

In response to the endpoint detection at step 748, a second wash process step 750 is performed to remove the residual tungsten layer. At step 750, a second voltage is provided from power source 242. The second voltage may be less than or equal to the voltage of the first barrier cleaning step 746. In one embodiment, the voltage is about 1.5 to about 2.5 volts. The voltage is maintained at a constant magnitude and flows through the electrolyte filling the opening 622 between the electrode 614 and the substrate 122 to drive the electrochemical mechanical planarization process. In general, the process of step 750 has a removal rate of about 300 to about 600 milliseconds per minute less than the first barrier removal step 746.

In step 752, the end point of the electrical process step 750 is determined. The endpoint may be determined using a second processing measurement provided by instrument 244 or sensor 254. In one embodiment, an endpoint is determined by detecting a second discontinuity of current sensed by meter 244. The second discontinuity appears when the area ratio between the oxide layers is fully exposed through the barrier layer remaining on the features formed in the substrate 122.

Optionally, a third cleaning process step 754 may be performed to remove residue chips from the barrier layer. Typically, the third wash process step 754 is a process that is controlled in time and is performed at a voltage level equal to or lower than the second wash process step 750. In one embodiment, the third cleaning process step 754 (also referred to as an overpolishing step) has a duration of about 15 to about 30 seconds.

7 illustrates one embodiment of a method 700 for electroprocessing conductive materials such as copper, tungsten, tantalum, tantalum nitride, titanium, titanium nitride, and the like, which method may be practiced on the system 100 described above. There will be. The method 700 may also be practiced in other electrical processing systems. In general, the method 700 is stored as a software routine in the memory 112 of the control unit 108. The software routine may also be stored and / or executed by a second CPU (not shown) located remote from hardware controlled by the CPU 110.

The method 700 begins at step 702 by performing a bulk electrochemical process on a conductive layer formed on a substrate 122, for example a copper layer. In one embodiment, bulk process step 702 is performed at the first ECMP station 128. Generally, bulk process step 702 ends when the thickness of the conductive layer is between about 2000 and about 1000 microns.

Next, a multi-step electrochemical cleaning step 704 is performed to expose the underlying barrier layer by removing residual copper material, which is typically tantalum, tantalum nitride, titanium, titanium nitride, or the like. The cleaning step 704 may be performed at the first ECMP station 128 or at one of the other ECMP stations 130, 132.

After the cleaning step 704, an electrochemical barrier removal step 706 is performed. Typically, the electrochemical barrier removal step 706 is performed at the third ECMP station 132, but may instead be performed at one of the other ECMP stations 128, 130.

In one embodiment, the bulk processing step 702 is performed by moving the substrate 122 held in the flattening head 204 upwards of the processing pad assembly 222 disposed in the first ECMP station 128. 712). Although the pad assemblies of FIGS. 2, 3A, 4A-4C and 5 have been used, in one embodiment, the pad and contact assemblies shown in FIGS. 3B-3C and 6 may be used instead. In step 714, the flattening head 204 is lowered toward the platen assembly 230 to contact the substrate 122 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 step 716, relative motion between the substrate 122 and the processing pad assembly 222 is provided. In one embodiment, the flattening head 204 is rotated at less than about 50 rpm and the pad assembly 222 is rotated at less than about 50 rpm.

In step 718, electrolyte is supplied to the processing pad assembly 222 to form a conductive path between the substrate 122 and the electrode 294. 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 maintained at a constant magnitude of about 4 to about 5 amps. Steps 176, 178 and 719 are performed substantially simultaneously.

In embodiments where tungsten is processed, the current is about three of the current used in copper processing to achieve the same removal rate. For example, step 719 provides about 12 to about 15 amps for removal of the tungsten conductive layer.

The top surface of the pad assembly 222 is in contact with the substrate 122 and allows current to be connected. The electrolyte filling the opening 210 between the electrode 292 and the substrate 122 provides a conductive path between the power source 242 and the substrate 122 to drive the electrochemical mechanical planarization process, resulting in such a step. The anodization method at 720 removes conductive material such as copper deposited on the surface of the substrate 122. In general, the process of step 720 has a tungsten removal rate of about 6000 m 3 / min.

In step 722, an endpoint of the bulk electrical process is determined. The first processing measure provided by instrument 244 may be used to determine the endpoint. Meter 244 provides charge, voltage or current information used to determine the residual thickness of a conductive material (eg, copper layer) on a substrate. In other embodiments, optical techniques such as interferometers using sensors 254 may be used. The residual thickness can be measured directly or can be calculated by subtracting the amount of material removed from the predetermined starting film thickness. In one embodiment, the endpoint may be determined by comparing the charge removed from the substrate to the target amount of charge for a predetermined region of the substrate. Examples of endpoint techniques that can be used are disclosed in US Patent Application No. 10 / 056,316, filed Jan. 22, 2002, and US Patent Application No. 10 / 456,851, filed June 6, 2002.

Step 722 is configured to detect an endpoint of the process prior to breakthrough of the copper layer. In one embodiment, the residual copper layer has a thickness of about 1000 to about 2000 mm 3 in step 722.

Hereinafter, one embodiment of the cleaning processing step 704 will be described with reference to a graph 800 showing the current trace 802 and the voltage trace 804 shown in FIG. Sizes are listed on the Y-axis 806 and times are written on the X-axis 808.

The cleaning processing step 704 begins at step 724 by moving the substrate 122 held in the planarization head 204 upwards of the processing pad assembly 604 disposed in the second ECMP station 130. . In step 726, the flattening head 204 is lowered toward the platen assembly 602 to contact the substrate with the top surface of the pad assembly 604. Although the pad assembly shown in FIG. 6 is used in one embodiment, the pad and contact assemblies shown in FIGS. 2, 3A-3C, 4A-4C, and 5 may be used instead. In one embodiment, the substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 pounds per square inch (psi). In step 728, electrolyte is supplied to the processing pad assembly 604 to form a conductive path between the substrate 122 and the electrode 614.

In a first cleaning process step 730, a first current is provided from the power source 242 and flows between the electrode 614 and the top surface of the pad assembly 604. In one embodiment, the current (as shown by current trace 802) is maintained at a constant magnitude of about 4 to about 5 amperes and fills the opening 622 between electrode 614 and substrate 122. It flows through to drive the electrochemical mechanical planarization process. In general, the process of step 730 has a removal rate that is approximately similar to step 722.

In step 732, the endpoint of the electrical process step 730 is determined. The endpoint may be determined using the first processing measurements provided by instrument 244 or sensor 254. In one embodiment, the endpoint is determined by detecting the first discontinuity 810 of the voltage sensed by the meter 244. The first discontinuity 810 appears when the underlying layer begins to penetrate the conductive layer (eg, copper layer). Because the bottom layer has a different resistance than the copper layer, the resistance across the processing cell (ie, from the conductive portion of the substrate to the electrode 292) changes as the area of the copper layer relative to the exposed area of the bottom layer changes.

The use of current (or voltage) for endpoint detection is particularly useful in the tungsten removal process because the close reflexivity between tungsten and the underlying titanium nitride material makes conventional optical detection difficult.

In response to the endpoint detection at step 732, a second clean process step 734 is performed to remove the residual copper layer. At step 734, a second current is provided from power source 242. The current is maintained at a constant magnitude less than the current of step 730 and flows through the electrolyte filling the opening 622 between the electrode 614 and the substrate 122 to drive the electrochemical mechanical planarization process. For example, the current will be provided at about 1.5 to about 4.5 amps. Generally, the process of step 734 has a removal rate of about 500 to about 1500 milliseconds per minute. In the tungsten process, the current will be about 4.5 to about 13.5 amps to achieve a removal rate of 500-2000 mA / min.

In step 736, the end point of the electrical process step 734 is determined. The endpoint may be determined using the second processing measurement value provided by meter 244 or sensor 254. In one embodiment, the endpoint is determined by detecting the second discontinuity 812 of the voltage sensed by the meter 244. The second discontinuity 812 appears when the underlying layer is fully exposed and the copper layer remains substantially within the features formed in the substrate 122 (ie, copper lines and vias).

Optionally, a third cleaning process step 738 may be performed to remove residue chips from the conductive layer. Typically, the third wash process step 738 is a process that is controlled in time and is performed at a current level that is equal to or lower than the second wash process step 732. In one embodiment, the third cleaning process step 738 (also referred to as an overpolishing step) has a duration of about 15 to about 30 seconds. During step 738, the current may be lowered to a level lower than the current level in the previous processing step, for example up to about 0.5-3 amps.

By moving the substrate 122 held in the planarization head 204 over the processing pad assembly 604 disposed in the third ECMP station 132, the electrochemical barrier removal step 706 begins at step 740. do. In step 742, the flattening head 204 is lowered toward the platen assembly 602 to contact the substrate 122 with the top surface of the pad assembly 604. Although the pad assembly of FIG. 6 has been used, in one embodiment, the pad and contact assemblies shown in FIGS. 2, 3A-3C, 4A-4C and 5 may be used instead. In one embodiment, the substrate 122 is pressed against the pad assembly 604 with a force of less than about 2 pounds per square inch (psi). In step 744, electrolyte is supplied to the processing pad assembly 604 to form a conductive path between the substrate 122 and the electrode 614. The electrolyte used for barrier removal will be different from the electrolyte used for copper removal.

In one embodiment, the electrolyte composition provided at the third ECMP station 132 comprises phosphoric acid or sulfuric acid and a catalyst. The electrolyte can be configured to prevent or inhibit the formation of oxides on the barrier layer. The catalyst is selected to selectively react with the complexing agent by activating the Ti or other barrier layer, thus allowing easy removal and / or decomposition of the barrier layer with or without minimal removal of copper or tungsten. The electrolyte composition may further comprise detergents such as amino acids, organic amines and phthalic acid or other organic phenols, picolinic acid or derivatives thereof, and pH adjusters. The electrolyte may optionally include abrasive agents. Abrasive agents are preferred for removing some of the underlying oxide layer.

In a first barrier process step 746, a first current is provided from the power source 242 and flows between the electrode 614 and the top surface of the pad assembly 604. In one embodiment, a current is maintained at a constant magnitude of about 1.5 to about 6 amps and flows through an electrolyte filling the opening 622 between the electrode 614 and the substrate 122 to drive the electrochemical mechanical planarization process. In general, the process of step 746 has a removal rate of about 500-2000 dB / min.

In step 748, the end point of the electrical process step 746 is determined. The endpoint may be determined using the first processing measurements provided by instrument 244 or sensor 254. The current and voltage traces of the electrochemical barrier removal step 706 are similar to the traces of FIG. 8 and are therefore omitted for clarity. In one embodiment, the endpoint of step 748 is determined by detecting the first discontinuity of the voltage sensed by meter 244. The first discontinuity appears when the underlying layer (usually an oxide) begins to penetrate the barrier layer. Since the underlying layer has a different resistance than the barrier layer, a change in resistance across the processing cell indicates penetration of the barrier layer.

In response to the endpoint detection at step 748, a second wash process step 750 is performed to remove the residual copper layer. At step 748, a second voltage is provided from power source 242. The current is maintained at a constant magnitude less than the current of step 746 and flows through the electrolyte filling the opening 620 between the electrode 614 and the substrate 122 to drive the electrochemical mechanical planarization process. For example, in one embodiment, a current of about 3.5 to about 2.5 amps can be provided. The process of step 748 has a removal rate of about 1000 milliseconds per minute.

In step 752, the end point of the electrical process step 750 is determined. The endpoint may be determined using a second processing measurement provided by instrument 244 or sensor 254. In one embodiment, an endpoint is determined by detecting a second discontinuity of the voltage sensed by meter 244. The second discontinuity appears when the oxide layer is fully exposed.

Optionally, a third cleaning process step 754 may be performed to remove residue chips from the barrier layer. Typically, third wash process step 754 is a time controlled process and is performed at a current level equal to or lower than second wash process step 746. In one embodiment, the third cleaning process step 754 (also referred to as an overpolishing step) has a duration of about 15 to about 30 seconds.

9 is a flowchart illustrating another embodiment of a method 900 for electrochemical processing. The method 900, except that the electrochemical process is driven by a constant voltage provided by the power source 242 as indicated in the graphs of the current and voltage traces 1002, 1004 shown in FIG. It is substantially similar to the method 800 described above. The size is written on the Y-axis 1006 and the time is written on the X-axis 1008.

In one embodiment, the method 900 begins at step 902 by performing a bulk electrochemical process on a conductive layer such as, for example, a copper layer formed on the substrate 122. In general, the bulk processing step 902 ends when the thickness of the conductive layer is between about 2000 and about 1000 microns.

Next, a multi-step electrochemical cleaning step 904 is performed to expose the underlying barrier layer by removing residual copper material. The cleaning step 904 may be performed at the first ECMP station 128 or at one of the other ECMP stations 130, 132. After the cleaning step 904, an electrochemical barrier removal step 906 is performed. Typically, the electrochemical barrier removal step 906 is performed at the third ECMP station 132, but may instead be performed at one of the other ECMP stations 128, 130.

In one embodiment, the bulk processing step 902 is substantially similar to the bulk processing step 702 described above. Bulk processing step 702 drives the electrochemical process using a substantially constant voltage provided from power source 242. In one embodiment, the voltage is maintained at a substantially constant magnitude of about 1 to about 4 volts. The endpoint of the bulk electrical process is determined by the method as described above, for example using the sum of the charges removed from the conductive layer and other methods for detecting the endpoint. It should be noted that during the first processing step shown in the left portion of the trace 1002, the current decreases as the conductive layer becomes thinner. This is particularly measurable upon tungsten removal, so that the slope of the trace can be used to determine the removal rate or remaining thickness of the conductive layer. The thickness versus current change information can be obtained empirically or calculated and stored in a database accessible to the controller 108 in use in endpoint detection, removal profile control and other process control.

A cleaning processing step 904 is now performed. Cleaning processing step 904 is similar to step 904 described above, except that the electrochemical process is driven at a constant voltage. In one embodiment, the voltage is constant across both bulk and clean processing steps 902, 904. In another embodiment, the voltage driving clean processing step 904 may be less than the voltage of the previous processing step.

The first end point of processing step 904 can be determined by monitoring by meter 244 to detect first discontinuity 1010 in current trace 1002. Instead, other methods may be used to determine the first end point. Detection of the first discontinuity 1010 means breakthrough of the copper layer.

The second end point of the processing step 904 is determined by detecting the second discontinuity 1012 in the current trace 1002. The second end point may be determined by other methods. The second discontinuity indicates cleaning of the copper layer. Optionally, a time-controlled overpolishing step may be performed during the cleaning processing step 904 after detection of the second end point as determined by the second discontinuity 1012.

The electrochemical barrier removal step 906 is substantially similar to the barrier removal step 706 described above, except that the electrochemical process is driven at a substantially constant voltage. In general, the voltage is maintained at a substantially constant magnitude that is equal to or less than the voltage used in steps 902 and 904. In one embodiment, the voltage remains substantially constant at a magnitude less than about 3 volts at least in removing the bulk portion of the barrier. The voltage can be selectively reduced during the residue removal portion of the barrier removal process.

Accordingly, the present invention provides an improved method and apparatus for electrochemically planarizing a substrate. The device makes it possible to effectively remove bulk and residual metals and barrier materials from the substrate using a single tool. Advantageously, by using an electrochemical process in the entire metal and barrier removal process, it is possible to reduce the wear and dishing of the conductor during processing and to minimize the loss of oxides. It will be appreciated that by reversing the polarity of the bias applied to the electrode and the substrate, it may be possible to deposit material on the substrate using the methods and apparatus disclosed herein.

While the embodiments of the present invention have been described above, other embodiments of the present invention will be understood within the basic scope of the present invention, and the scope of the present invention is determined by the following claims.

Claims (38)

As a method of electroprocessing a substrate: Forming an electrically-conductive path through the electrolyte between the exposed layer of barrier material on the substrate and the electrode; Forcing the substrate against a processing pad assembly with a force of less than about 2 psi; Providing motion between the substrate and the pad assembly in contact with each other; And Electrochemically removing a portion of the exposed layer during a first electrochemical processing step at a barrier processing station. The method of claim 1, wherein the first electrochemical processing step comprises: Detecting an end point of the first electrochemical processing step upon or immediately before the breakthrough of the exposed layer of barrier material; Electrochemically processing the exposed layer of barrier material during a second electrochemical processing step at the barrier processing station; And Detecting an end point of the second electrochemical processing step. The method of claim 1, wherein the forming of the conductive paths comprises: Flowing an electrolyte into contact with the substrate through the processing pad assembly from underneath the electrode. 3. The process of claim 2, wherein the second electrochemical processing step is: Detecting a first end point; Electroprocessing the substrate at a slow rate; And Detecting a second end point representative of the residual barrier material being cleaned from the substrate. The method of claim 4, wherein the first endpoint detection step comprises: Detecting a first discontinuity of current flowing between the substrate and the electrode. 6. The method of claim 5, wherein the second endpoint detection step is: Detecting a second discontinuity of current flowing between the substrate and the electrode. The method of claim 1, wherein the electrolyte further comprises at least one of sulfuric acid, phosphoric acid, amino acids, organic amines, phthalic acid, organic phenolic acid, picolinic acid, or derivatives thereof and a catalyst. The method of claim 1, further comprising electrochemically removing a conductive layer disposed above the barrier layer in a processing system. The method of claim 1, wherein the barrier material is at least one of ruthenium, titanium, titanium nitride, tantalum, tantalum nitride. A method of electrochemically processing a substrate having an exposed conductive layer and an underlying barrier layer: Forming an electrically-conductive path through an electrolyte between an 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 during a first electrochemical processing step at a first processing station; Transferring the substrate to a barrier removal station; Pressing the substrate with a force of less than about 2 psi against a processing pad assembly disposed in the barrier removal station; Forming an electrically-conductive path through an electrolyte between the barrier layer and an electrode; And Electrochemically processing the barrier layer. 12. The method of claim 10, further comprising: detecting an endpoint of the first electrochemical processing step at or before breakthrough of the exposed layer of conductive material; Electrochemically processing the exposed layer of conductive material during a second electrochemical processing step; And Detecting an end point of the second electrochemical processing step. The method of claim 10, wherein the barrier processing step comprises: Detecting an end point of the first electrochemical processing step upon or immediately before the breakthrough of the exposed layer of barrier material; Electrochemically processing the exposed layer of barrier material during a second electrochemical processing step at the barrier processing station; And Detecting an end point of the second electrochemical processing step. The method of claim 12, wherein the second electrochemical processing step comprises: Overpolishing the substrate after the second end point detection. 13. The method of claim 12, wherein said first endpoint detection step comprises: Detecting a first discontinuity of current flowing between the substrate and the electrode. 15. The method of claim 14, wherein said second endpoint detection step comprises: Detecting a second discontinuity of current flowing between the substrate and the electrode. The method of claim 10, wherein the electrolyte at the barrier removal station further comprises a catalyst and at least one of sulfuric acid or phosphoric acid. 17. The method of claim 16, wherein the electrolyte at the first processing station and the electrolyte at the barrier removal station have different compositions. As a method of electrical processing of a substrate: Forming an electrically-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 during a first electrochemical processing step at a barrier processing station; Detecting an end point of the first electrochemical processing step upon or immediately before the breakthrough of the exposed layer of barrier material; Electrochemically processing the exposed layer of barrier material in a second electrochemical processing step at a barrier processing station; And Detecting an end point of the second electrochemical processing step. 19. The method of claim 18, further comprising: contacting a barrier material on the substrate with a processing pad assembly; And Moving the substrate relative to the pad assembly during a polishing movement. 19. The process of claim 18, wherein the second electrochemical processing step is: Detecting the first endpoint; Processing the substrate at a slow speed; And Detecting a second end point representative of the residual barrier material being cleaned from the substrate. The method of claim 20, wherein the first endpoint detection step comprises: Detecting a first discontinuity of the potential difference between the substrate and the electrode; The second end point detection step is: Detecting a second discontinuity of the potential difference between the substrate and the electrode. The method of claim 20, wherein the first endpoint detection step comprises: Detecting a first discontinuity of current flowing between the substrate and the electrode. 23. The method of claim 22, wherein said second endpoint detection step comprises: Detecting a second discontinuity of current flowing between the substrate and the electrode. 19. The method of claim 18, further comprising electrochemically removing a conductive layer disposed above the barrier layer in a processing system. 19. The method of claim 18, wherein the remaining thickness of the barrier layer is determined from a change in current between the substrate and the electrode. A method of electrochemically processing a substrate having an exposed conductive layer and an underlying barrier layer: Forming an electrically-conductive path through the electrolyte between the exposed layer of conductive material on the substrate and the electrode; Electrochemically removing a portion of the exposed layer during a first electrochemical processing step at a first processing station; Detecting an end point of the first electrochemical processing step upon or immediately before the breakthrough of the exposed layer of conductive material; Electrochemically processing the exposed layer of conductive material in a second electrochemical processing step; Detecting an end point of the second electrochemical processing step; Transferring the substrate to a barrier removal station; And Electrochemically processing the barrier layer. 27. The method of claim 26, wherein the first electrochemical processing step is performed at the first processing station; And Transferring the substrate to a second processing station in which the second electrochemical processing step is performed. 28. The method of claim 27, wherein said second electrochemical processing step comprises: Detecting the first endpoint; Processing the substrate at a slow speed; And Detecting a second end point representative of the residual barrier material being cleaned from the substrate. 29. The method of claim 28, wherein said first endpoint detection step comprises: Detecting a first discontinuity of the potential difference between the substrate and the electrode; And Detecting a second discontinuity in the potential difference between the substrate and the electrode. 29. The method of claim 28, wherein said first endpoint detection step comprises: Detecting a first discontinuity of current flowing between the substrate and the electrode; And Detecting a second discontinuity of current flowing between the substrate and the electrode. 27. The method of claim 26, wherein said barrier electrochemical processing comprises: Detecting the first endpoint; Processing the substrate at a slow speed; And Detecting a second end point representative of the barrier material being cleaned from the substrate. 32. The method of claim 31, wherein said first endpoint detection step comprises: Detecting a first discontinuity of the potential difference between the substrate and the electrode; And Detecting a second discontinuity in the potential difference between the substrate and the electrode. 32. The method of claim 31, wherein said first endpoint detection step comprises: Detecting a first discontinuity of current flowing between the substrate and the electrode; And Detecting a second discontinuity of current flowing between the substrate and the electrode. 27. The method of claim 26, further comprising determining a thickness of the conductive material from a change in current. A method of electrochemically processing 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 the processing system; Forming an electrically-conductive path through the electrolyte between the exposed layer of conductive material on the substrate and the electrode; Providing a polishing movement between the substrate and the processing pad assembly in contact with each other; Electrochemically removing a portion of the exposed layer during a first electrochemical processing step at the first processing station; Detecting an end point of the first electrochemical processing step upon or immediately before the breakthrough of the exposed layer of conductive material; Electrochemically processing the exposed layer of conductive material in a second electrochemical processing step; Detecting an end point of the second electrochemical processing step; Transferring the substrate to a barrier removal station; Forming an electrically-conductive path through an electrolyte between an electrode disposed in the barrier removal station and a barrier layer; Electrochemically removing a portion of the barrier layer during a first electrochemical barrier processing step at the barrier processing station; Detecting an end point of the first electrochemical barrier processing step at or before breakthrough of the barrier material; Electrochemically processing the barrier material in a second electrochemical barrier processing step at a barrier processing station; And Detecting an end point of the second electrochemical processing step. 36. The method of claim 35, wherein detecting at least two endpoints of the barrier and conductive material processing steps comprises: Detecting discontinuities in the potential difference between the substrate and the electrode. 36. The method of claim 35, wherein detecting at least two endpoints of the barrier and copper processing steps comprises: Detecting discontinuities in the current measured between the substrate and the electrode. 36. The method of claim 35, further comprising detecting the remaining thickness of the conductive material from changes in current.

Images