US20090280727A1

US20090280727A1 - Polishing system with three headed carousel

Info

Publication number: US20090280727A1
Application number: US12/118,438
Authority: US
Inventors: Lakshmanan Karuppiah; Tetsuya Ishikawa; Donald J.K. Olgado; Allen L. D'Ambra; Hung Chih Chen
Original assignee: Individual
Current assignee: Applied Materials Inc
Priority date: 2008-05-09
Filing date: 2008-05-09
Publication date: 2009-11-12

Abstract

Embodiments of the present invention provide a polishing module configured to use in a polishing system. The polishing module comprises a base member, two polishing stations disposed on the base member, one load cup, and a carousel having three polishing heads.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
Embodiments of the invention generally relate to an apparatus and method for polishing or planarization of semiconductor substrates.
2. Description of the Related Art
Sub-micron multi-level metallization is one of the key technologies for the next generation of ultra large-scale integration (ULSI). The multilevel interconnects that lie at the heart of this technology require planarization of interconnect features formed in high aspect ratio apertures, including contacts, vias, trenches and other features. Reliable formation of these interconnect features is very important to the success of ULSI and to the continued effort to increase circuit density and quality on individual substrates and die.
In the fabrication of integrated circuits and other electronic devices, multiple layers of conductive, semi-conductive, and dielectric materials are deposited on or removed from a surface of a substrate. Thin layers of conductive, semiconductive, and dielectric materials may be deposited by a number of deposition techniques. As layers of materials are sequentially deposited and removed, the uppermost surface of the substrate may become non-planar across its surface and require planarization.
Planarization is generally performed using Chemical Mechanical Polishing (CMP) and/or Electro-Chemical Mechanical Deposition (ECMP). A planarization method typically requires that the substrate be mounted in a wafer head, with the surface of the substrate to be polished exposed. The substrate supported by the head is then placed against a rotating polishing pad. The head holding the substrate may also rotate, to provide additional motion between the substrate and the polishing pad surface. Further, a polishing slurry (typically including an abrasive and at least one chemically reactive agent therein, which are selected to enhance the polishing of the topmost film layer of the substrate) is supplied to the pad to provide an abrasive chemical solution at the interface between the pad and the substrate. The combination of polishing pad characteristics, the specific slurry mixture, and other polishing parameters can provide specific polishing characteristics.
Polishing is generally performed in multiple steps, each having specific polishing characteristics, to achieve desired results. A polishing system generally has two or more polishing pads configured to perform different polishing steps, and a substrate transfer assembly configured to transfer the substrates among the two or more polishing pads.
However, it remains challenging to achieve high throughput and flexibility to meet process requirements in a polishing system.
Therefore, there is a need for a polishing system with flexibility and improved throughput.

SUMMARY OF THE INVENTION

The present invention provides methods and apparatus for polishing semiconductor substrates with improved throughput.
One embodiment of the present invention provides a polishing module configured to use in a polishing system comprising a base member, two polishing stations disposed on the base member, wherein each of the two polishing stations is configured to polish substrates, a carousel supported by the base member, wherein the carousel comprises three substrate heads each configured to transfer a substrate and polish the substrate against the two polishing stations, and the carousel is configured to simultaneously rotate the three substrate heads about a carousel axis, and a load cup disposed on the base member, wherein the load cup is configured to load substrates to the three substrates heads and to unload substrates from the three polishing heads, and the two polishing stations and the load cup are positioned to allow simultaneous alignment of each of the three substrate heads with one of the two polishing stations and the load cup.
Another embodiment of the present invention provides a polishing system comprising a factory interface configured to receive unpolished substrates from substrate transferring cassettes and transfer polished substrates to the substrate transferring cassettes, a substrate transferring platform configured to receive substrates from the factory interface, a polishing assembly configured to polishing substrates in one or more polishing steps, wherein the polishing assembly comprises a first polishing module comprises a first base member, first and second polishing stations disposed on the first base member, a first carousel supported by the first base member, wherein the first carousel comprises three substrate heads each configured to transfer a substrate and polish the substrate against the first and second polishing stations, and the first carousel is configured to simultaneously rotate the three substrate heads about a first carousel axis, and a first load cup disposed on the first base member, wherein the first polishing station, the second polishing station and the first load cup are positioned to allow simultaneous alignment of each of the three substrate heads of the first carousel with one of the first polishing station, the second polishing station and the first load cup, a polishing robot configured to transfer substrates from the substrate transferring platform to the polishing assembly, and a cleaning assembly to clean polished the substrates.
Yet another embodiment of the present invention provides a method for polishing a substrate comprising transferring a first substrate using a substrate transferring belt towards a polishing assembly, transferring the first substrate from the substrate transferring belt to a first load cup of the polishing assembly, loading the first substrate from the first load cup to a first substrate head mounted on a first carousel having three polishing heads, aligning the first substrate head with a first polishing station of the polishing assembly, polishing the first substrate in the first polishing station, aligning the first substrate head with the first load cup, and unloading the first substrate from the first substrate head to the first load cup.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1 is a schematic top view of a polishing module in accordance with one embodiment of the present invention.

FIG. 2 is a schematic sectional side view of the polishing module of FIG. 1.

FIG. 3 is a schematic plan view of a polishing system in accordance with one embodiment of the present invention.

FIG. 4 is a schematic plan view of a polishing system in accordance with another embodiment of the present invention.

It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
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 disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

DETAILED DESCRIPTION

The present invention provides methods and apparatus for polishing semiconductor substrates with improved throughput and improved flexibility. In one embodiment of the present invention, three polishing heads are mounted on a carousel and are configured to transfer and process substrates among two polishing stations and one load cup. In one embodiment, two three headed carousels are used together. In another embodiment, a three headed carousel is used in combination with polishing heads mounted on pivoting arms.
FIG. 1 is a schematic top view of a polishing module 100 in accordance with one embodiment of the present invention. FIG. 2 is a schematic sectional side view of the polishing module 100 of FIG. 1.
The polishing module 100 is configured to be used alone or in combination in a polishing system. The polishing module 100 generally comprises a base member 101. Two polishing stations 102 a, 102 b, and a load cup 103 are disposed on the base member 101. The polishing module 100 further comprises a carousel 110 mounted on the base member 101. The carousel 110 comprises three head systems 107 a, 107 b, 107 c, each of which is configured to receive, transfer and process a substrate. The carousel 110 is configured to rotate the head systems 107 a, 107 b, 107 c simultaneously and to align the head systems 107 a, 107 b, 107 c with the polishing stations 102 a, 102 b, and the load cup 103.
Each polishing stations 102 a, 102 b comprises a rotatable platen 121 on which a polishing pad 124 is placed. Each polishing station 102 a or 102 b further includes a conditioner head 123 adapted on a rotatable arm 122. A detailed description for the rotatable platen 121 and the polishing pad 124 may be found in co-pending U.S. patent application Ser. No. 10/880,752, filed on Jun. 30, 2004, entitled “Method and Apparatus for Electrochemical Mechanical Processing”, which is herein incorporated as reference. A detailed description for the polishing pad 124 may be found in co-pending U.S. Pat. No. 6,575,825, entitled “CMP Polishing Pad”, which is herein incorporated as reference. Each of the polishing stations 102 may be configured to conduct chemical mechanical polishing (CMP), electrochemical mechanical polishing (ECMP) or buffing.
Each of the head systems 107 a, 107 b, 107 c is configured to receive one substrate, transfer the substrate among the polishing stations 102 a, 102 b and the load cup 103, and polish the substrate by pressing the substrate against any one of the polishing pads 124 on the polishing stations 102 a, 102 b. In one embodiment, the carousel 110 is supported by a center post 118 on the base 101. The carousel 110 is rotatable on the center post 118 about a carousel axis 104 by a motor assembly (not shown) located within the base 101. In one embodiment, the motor assembly may comprise a servo motor.
In one embodiment, the three head systems 107 a, 107 b, 107 c are identical and mounted on a carousel base plate 119 at equal angular intervals about the carousel axis 104. The center post 118 supports the carousel base plate 119 and allows the motor assembly to rotate the carousel base plate 119.
Each head system 107 a, 107 b, 107 c comprises a substrate head 112 which is rotatable about its own axis by a head-rotation motor 111 connected to the substrate head 112 by a shaft. The substrate heads 112 can rotate independently driven by the respective head-rotation motor 111. Each head system 107 a, 107 b, 107 c is independently movable along a slot 116 formed radially on the carousel base plate 119. In one embodiment, for each head system 107 a, 107 b, 107 c, the linear movement along the respectively slot 116 is realized through a slide mounted around the shaft between the head-rotation motor 111 and the substrate head 112. The linear movement of each head system 107 a, 107 b, 107 c is configured to adjust the radial position of each head system 107 a, 107 b, 107 c during alignment with the polishing stations 102 a, 102 b, and the load cup 103. The liner movement may also provide sweeping motion during polishing.
During processing, two of the three head systems 107 a, 107 b, 107 c are positioned above a respective polishing station 102 a, 102 b. The substrate retained on each substrate head 112 is lowered using substrate lowering/raising mechanism within the head system 107 a, 107 b, or 107 c. Polishing is conducted via a relative motion produced between the substrate retained therein and the platen 121 of the respective polishing station 102 a, 102 b. In one embodiment, the relative motion may be a result of a rotation of the platen 121, a rotation of the substrate head 112 and a sweeping motion of the substrate head 112. A suitable head system may be a Titan® polishing head available from Applied Materials, Inc. located in Santa Clara, Calif. A detailed description of the substrate head 112 may be found in U.S. Pat. No. 6,183,354, entitled “Carrier Head with a Flexible Membrane for a Chemical Mechanical Polishing”, and co-pending U.S. patent application Ser. No. 11/054,128 filed on Feb. 8, 2004, entitled “Multi-chamber Carrier Head with a Flexible Membrane”, which are herein incorporated as reference.
The load cup 103 is positioned on the base member 101 such that when two of the three head systems 107 a, 107 b, 107 c are in polishing position above the respective polishing stations 102 a, 102 b, the third head system may be aligned to the load cup 103. The load cup 103 is configured to receive/pass a substrate from/to a substrate transferor, such as a robot, pass/receive the substrate to/from each of the head systems 107 a, 107 b, 107 c. In one embodiment, the load cups 103 may be also adapted to be a wash station for a substrate to be cleaned therein. A detailed description of a load cup may be found in co-pending U.S. patent application Ser. No. 10/988,647, filed on Nov. 15, 2004, entitled “Load Cup for Chemical Mechanical Polishing”, which is herein incorporated as reference.
For a polishing system which is capable of performing multiple-step polishing using multiple polishing stations, flexibility and high throughput are both desired but are usually conflicting. On the one hand, ideal flexibility may be achieved by allowing “random access” of each polishing station. The random access may be achieved by using robots to transfer substrates among polishing stations. However, this random access resolution has a high overhead time of loading/unloading because substrates have to be loaded/unloaded at each polishing station, thus, reducing throughput. On the other hand, a carousel structure, which uses a carousel to transfer polishing heads and substrates mounted thereon among the multiple polishing stations, enables high throughput since loading/unloading is required only once for the entire processing. However, the carousel structure dictates a fixed number of sequential steps with limited flexibility.
The polishing module 100, which has a three-headed carousel and two polishing stations, combines flexibility to a high throughput carousel design by reducing the number of polishing heads of the carousel and allow two or more carousels to be used in combination. During processing, two of the three polishing heads are located over the two polishing stations performing polishing, while the third polishing head is positioned over the load cup performing loading and unloading simultaneously. The arrangement minimizes loading/unloading overhead because loading/unloading is performed in parallel with the polishing process. Two or more polishing modules may be used in combination for added flexibility.
FIG. 3 is a schematic plan view of a polishing system 200 in accordance with one embodiment of the present invention. The polishing system 200 generally includes a factory interface 201, a substrate transferring mechanism 202, a polishing robot 203, a polishing assembly 204, and a cleaning assembly 205.
The factory interface 201 generally comprises an internal robot 211 which is configured to transfer substrates to be polished from one or more substrate storage cassettes 212 to the substrate transferring mechanism 202, and to transfer polished and cleaned substrates from the cleaning assembly 205 back to the one or more substrate storage cassettes 212.
The internal robot 211 only contacts substrates when the substrates are free of polishing solution and is sometimes referred to as a dry robot. In the embodiment, four substrate storage cassettes 212 are connected to the factory interface. In one embodiment, the internal robot 211 may be mounted on a rail or track 213 configured to position the internal robot 211 laterally within the factory interface 201, thereby increasing the range of motion of the internal robot 201.
In one embodiment, the factory interface 201 may have an outlet port 214 designated to deliver unpolished substrates to the substrate transferring mechanism 202. The factory interface 201 may have an inlet port 215 designated to receive polished substrates from the cleaning assembly 205.
In one embodiment, the internal robot 211 of the factory interface 201 may be queued to transfer substrates to the substrate transferring mechanism 202 in synchronization with substrate transfer from the substrate transferring mechanism 202 to the polishing assembly 204 by the polishing robot 203.
In one embodiment, the substrate transferring mechanism 202 comprises a transferring belt 221 disposed between the factory interface 201 and a location within a range of motion of the polishing robot 203. During processing, the transferring-belt 221 may move a substrate transferring surface from the factory interface 201 towards the polishing robot 203 to carry a plurality of substrates 206 from the factory interface 201 towards the polishing assembly 204.
The polishing assembly 204 is modular and configured to perform different polishing recipes. In one embodiment, the polishing assembly 204 comprises two polishing modules 231, 241 disposed side by side. In one embodiment, the polishing modules 231, 241 may be similar to the polishing module 100 of FIG. 1.
The polishing module 231 comprises two polishing stations 233 a, 233 b, one load cup 234, and a carousel 232 configured to align three polishing heads 235 a, 235 b, 235 c with the polishing stations 233 a, 233 b, and the load cup 234. The polishing module 241 comprises two polishing stations 243 a, 243 b, one load cup 244, and a carousel 242 configured to align three polishing heads 245 a, 245 b, 245 c with the polishing stations 243 a, 243 b, and the load cup 244. The polishing modules 231, 241 are disposed symmetrically with the load cups 234, 244 next to one another.
The polishing robot 203 may be positioned in equal distance to the polishing cups 234, 244. During processing, the polishing robot 203 transfers unpolished substrates from the substrate transferring mechanism 202 to the load cups 234, 244, and transfer polished substrates from the load cups 234, 244 to the cleaning assembly 205. The polishing robot 203 may also transfer substrates between the load cups 234, 244 if the polishing recipe requires substrates to be polished in both the polishing modules 231, 241.
The polishing assembly 204 of the present invention may be used to perform a two step polishing in parallel, a four step polishing in series, or a three step polishing by splitting a long polishing step in two polishing stations. Parallel Two Step Polishing
An exemplary two step polishing may be performed parallel in the polishing modules 231, 241. For example, in the polishing module 231, the polishing station 233 a is configured to perform step one while the polishing station 233 b is configured to perform step two.
During processing, the polishing robot 203 drops off a first unpolished substrate in the load cup 234 and the polishing head 235 c can pick up the first substrate thereon.
The carousel 232 may then rotate to align the polishing head 235 c with the polishing station 233 a where the first polishing step is performed on the first substrate. At the same time, the polishing head 235 a is aligned with the load cup 234, where a second substrate may be loaded on the polishing head 235 a.
Upon completing the first polishing step, the carousel 232 rotates again to align the polishing head 235 c with the polishing station 233 b where the second polishing step is performed to the first substrate. At the same time, the polishing head 235 a is aligned with the polishing station 233 a wherein the first polishing step is performed to the second substrate. At the same time, the polishing head 235 b is aligned with the load cup 234, wherein a third substrate may be loaded onto the polishing head 235 b.
Upon completion of polishing steps in both polishing stations 233 a, 233 b, the carousel 232 may rotate again to align the polishing head 235 c with the load cup 234, wherein the first substrate is unloaded and subsequently transferred to the cleaning assembly 205 by the polishing robot 203. A fourth substrate may be transferred to the load cup 234 by the polishing robot 203 from the substrate transferring mechanism 202. The fourth substrate is then loaded on the polishing head 235 c and waiting for the completion of polishing to the second and third substrates in the polishing stations 233 a, 233 b. The process may be repeated.
Similarly, in the polishing module 241, the polishing station 243 a is configured to perform step one while the polishing station 243 b is configured to perform step two. And a similar polishing process may be performed in parallel.

Four Step Polishing

An exemplary four step polishing may be performed in the polishing modules 231, 241. For example, the polishing station 233 a is configured to perform step one, the polishing station 233 b is configured to perform step two, the polishing station 243 a is configured to perform step three, and the polishing station 243 b is configured to perform step four.
During processing, the polishing robot 203 drops off a first unpolished substrate in the load cup 234 and the polishing head 235 c can pick up the first substrate thereon.
The carousel 232 may then rotate to align the polishing head 235 c with the polishing station 233 a where the first polishing step is performed on the first substrate. At the same time, the polishing head 235 a is aligned with the load cup 234, where a second substrate may be loaded on the polishing head 235 a.
Upon completing the first polishing step, the carousel 232 rotates again to align the polishing head 235 c with the polishing station 233 b where the second polishing step is performed to the first substrate. At the same time, the polishing head 235 a is aligned with the polishing station 233 a wherein the first polishing step is performed to the second substrate. At the same time, the polishing head 235 b is aligned with the load cup 234, wherein a third substrate may be loaded onto the polishing head 235 b.
Upon completion of polishing steps in both polishing stations 233 a, 233 b, the carousel 232 may rotate again to align the polishing head 235 c with the load cup 234, wherein the first substrate is unloaded and subsequently transferred to the load cup 244, wherein the first substrate is loaded on the polishing head 245 b. A fourth substrate may be transferred to the load cup 232 by the polishing robot 203 from the substrate transferring mechanism 202. The fourth substrate is then loaded on the polishing head 235 c and waiting for the completion of polishing to the second and third substrates in the polishing stations 233 a, 233 b. The process is repeated.
After loading the first substrate in the polishing head 245 b, the carousel 242 may then rotate to align the polishing head 245 b with the polishing station 243 a where the third polishing step is performed on the first substrate. At the same time, the polishing head 245 c is aligned with the load cup 244, where the second substrate is transferred from the load cup 234 and may be loaded on the polishing head 245 c.
Upon completing the third polishing step, the carousel 242 rotates again to align the polishing head 245 b with the polishing station 243 b where the fourth polishing step is performed to the first substrate. At the same time, the polishing head 245 c is aligned with the polishing station 243 a wherein the third polishing step is performed to the second substrate. At the same time, the polishing head 245 a is aligned with the load cup 244, wherein the third substrate is transferred from the load cup 234 and may be loaded onto the polishing head 245 a.
Upon completion of polishing steps in both polishing stations 243 a, 243 b, the carousel 242 may rotate again to align the polishing head 245 a with the load cup 244, wherein the first substrate is unloaded and subsequently transferred to the cleaning assembly 205. The fourth substrate is then in queue in the load cup 244, wherein the fourth substrate is loaded on the polishing head 245 b. At the same time, the second and third substrates are being polished in the polishing stations 243 a, 243 b. Upon completion of the polishing, the process is repeated.

Three Step Polishing

In one embodiment, a three step polishing may be performed using the polishing assembly 204. In one embodiment, the longest polishing step of the process may be split and performed in two consecutive steps. In another embodiment, the longest polishing step may be split to two parallel steps. Thus, the three step polishing becomes a four step polishing. An exemplary process may be similar to the four step polishing described above.
The cleaning assembly 205 is configured to remove dislodged particles and the abrasive polishing material from polished substrates, and then rinse and dry the polished substrates. There are a number of different cleaning methods and mechanisms that may be used individually or in combination in a given cleaning process. For example, a cleaning sequence may include Megasonic vibration, brush-scrubbing and/or bevel cleaning, in addition to further rinsing and drying procedures. The type and number of procedures employed may vary depending on the semiconductor device processing application.
In one embodiment, the cleaning assembly 205 may be a modular, configurable system in which distinct cleaning and drying modules can be arranged in different combinations selectable by a user of the system. A detailed description of a modular cleaning system may be found in U.S. patent application Ser. No. 11/963,458, filed Dec. 21, 2007, entitled “Systems and Methods for Modular and Configurable Substrate Cleaning” (Attorney Docket No. 10860), which is incorporated herein by reference.
In one embodiment, the cleaning assembly 205 may comprises a substrate receiving dock 251, wherein polished substrates may be dropped off by the polishing robot 203. The receiving dock 251 may have a substrate handler configured to orient the substrates in desired orientations for subsequent cleaning process. For example, the substrates are generally horizontally oriented with device side facing down during polishing, while the substrates may be required to be vertical, or horizontal but with device side facing up. An exemplary substrate receiving dock and substrate handler may be found in U.S. patent application Ser. No. 12/026,000, filed Feb. 5, 2008, entitled “Edge Contact Gripper” (Attorney Docket No. 12113), which is incorporated herein by reference.
The cleaning assembly 205 further comprises a wet cleaning module 252 wherein polished substrates may be cleaned to remove particles from the substrates. The wet cleaning module 252 may use various cleaning methods, such as Megasonic vibration, brush-scrubbing, bevel cleaning, and rinsing. Cleaning and rinsing solutions are generally used in the wet cleaning module 252, and substrates stays wet. The wet cleaning module 252 may comprise vertical cleaners, horizontal cleaners, or the combination of vertical and horizontal cleaners. Detailed description of wet cleaner modules may be found in U.S. patent application Ser. No. 11/963,458, filed Dec. 21, 2007, entitled “Systems and Methods for Modular and Configurable Substrate Cleaning” (Attorney Docket No. 10860), and U.S. patent application Ser. No. 11/961,587, filed Dec. 20, 2007, entitled “Horizontal Megasonic Module for Cleaning Substrates” (Attorney Docket No. 10858), which are incorporated herein by reference.
The cleaning assembly 205 further comprises a dryer 254 configured to remove any vapor of cleaning and rinsing solution from cleaned substrates. Detailed description of an exemplary dryer may be found in U.S. patent application Ser. No. 11/967,533, filed Dec. 31, 2007, entitled “Multiple Substrate Vapor Drying System and Methods” (Attorney Docket No. 10857), which is incorporated herein by reference.
The cleaning assembly 205 may further comprise a cleaning robot 253 configured to transfer substrates within the cleaning assembly 205. For example, the cleaning robot 253 may transfer substrates within the wet cleaning module 252 or from the wet cleaning module 252 to the dryer 254.
The dryer 254 may be positioned adjacent the inlet port 215 of the factory interface 201 so that the internal robot 211 of the factory interface 211 may retrieve polished, cleaned and dried substrates at an outlet of the dryer 254.
FIG. 4 is a schematic plan view of a polishing system 200 a in accordance with another embodiment of the present invention. The polishing system 200 a is similar to the polishing system 200 of FIG. 3 except that the polishing system 200 a comprises a polishing assembly 207 which is different from the polishing assembly 204 of the polishing system 200. The polishing assembly 207 comprises two different polishing modules 241 and 271, and is configured to optimize a three step polishing with a long step.
The polishing assembly 207 is modular and configured to perform different polishing recipes. In one embodiment, the polishing module 241 may be similar to the polishing module 100 of FIG. 1.
The polishing module 271 comprises two polishing stations 273 a, 273 b, one load cup 276, and two polishing head assembly 272 a, 272 b. The polishing head assembly 272 a comprises a pivoting arm 274 a and a polishing head 275 a mounted on the pivoting arm 274 a. The pivoting arm 274 a is configured to align the polishing head 275 a with the load cup 276 during loading/unloading, and to align the polishing head 275 a with the polishing station 273 a during polishing. The polishing head assembly 272 b comprises a pivoting arm 274 b and a polishing head 275 b mounted on the pivoting arm 274 b. The pivoting arm 274 b is configured to align the polishing head 275 b with the load cup 276 during loading/unloading, and to align the polishing head 275 b with the polishing station 273 b during polishing. The configuration of the polishing module 271 increases flexibility of the polishing assembly 207 and also reduces cross contamination by limiting the polishing heads 275 a, 275 b to one polishing station.
The polishing modules 231, 271 are disposed symmetrically with the load cups 276, 244 next to one another.
The polishing assembly 207 of the present invention may be used to perform various polishing processes. Particularly, the polishing assembly 207 may be used to perform a three step polishing process with a long step one or a long step two.
Three Step Polishing with a Long Step One
An exemplary three step polishing with a long step one may be performed in the polishing modules 271, 241. For example, the polishing station 273 a and 273 b are both configured to perform step one, the polishing station 243 a is configured to perform step two, and the polishing station 243 b is configured to perform step three. The longest step, step one in this example, is performed in two polishing stations 273 a, 274 a, while the shorter steps are performed in series in the polishing module 241 having a three headed carousel.
During processing, the polishing robot 203 drops off a first unpolished substrate in the load cup 276 and the polishing head 275 a can pick up the first substrate thereon.
The pivoting arm 274 a may then pivot to align the polishing head 275 a with the polishing station 273 a where the first polishing step is performed on the first substrate.
Upon the polishing head 275 a vacant the load cup 276, a second substrate may be dropped off of the polishing robot 203. The polishing head 275 b may be aligned with the load cup 276, where the second substrate may be loaded on the polishing head 275 b. The pivoting arm 274 b may then pivot to align the polishing head 275 b with the polishing station 273 b where the first polishing step is performed on the second substrate.
Upon completing the first polishing step to the first substrate, while the second substrate is still being polished, the pivoting arm 274 a pivots again to align the polishing head 275 a with the load cup 276 wherein the first substrate is unloaded and subsequently transferred to the load cup 244 of the polishing module 241. A third substrate may be delivered to the load cup 276 and loaded on the polishing head 275 a. The polishing head 275 a is then pivoted to the polishing station 273 a to perform the first polishing step to the third substrate.
The process described above may be repeated for the subsequent substrates.
After transferred to the load cup 244, the first substrate is loaded onto the polishing head 245 b. After loading the first substrate in the polishing head 245 b, the carousel 242 may then rotate to align the polishing head 245 b with the polishing station 243 a where the second polishing step is performed on the first substrate. At the same time, the polishing head 245 c is aligned with the load cup 244, where the second substrate is transferred from the load cup 276 and may be loaded on the polishing head 245 c.
Upon completing the second polishing step to the first substrate and loading the second substrate on the polishing head 245 c, the carousel 242 rotates again to align the polishing head 245 b with the polishing station 243 b where the third polishing step is performed to the first substrate. At the same time, the polishing head 245 c is aligned with the polishing station 243 a wherein the second polishing step is performed to the second substrate. At the same time, the polishing head 245 a is aligned with the load cup 244, wherein the third substrate is transferred from the load cup 276 and may be loaded onto the polishing head 245 a.
Upon completion of polishing steps in both polishing stations 243 a, 243 b, the carousel 242 may rotate again to align the polishing head 245 a with the load cup 244, wherein the first substrate is unloaded and subsequently transferred to the cleaning assembly 205. The fourth substrate is then in queue in the load cup 244, wherein the fourth substrate is loaded on the polishing head 245 b. At the same time, the second and third substrates are being polished in the polishing stations 243 a, 243 b. Upon completion of the polishing, the process may be repeated for subsequent substrates.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A polishing module configured to use in a polishing system, comprising:

a base member;

two polishing stations disposed on the base member, wherein each of the two polishing stations is configured to polish substrates;

a carousel supported by the base member, wherein the carousel comprises three substrate heads each configured to transfer a substrate and polish the substrate against the two polishing stations, and the carousel is configured to simultaneously rotate the three substrate heads about a carousel axis; and

a load cup disposed on the base member, wherein the load cup is configured to load substrates to the three substrates heads and to unload substrates from the three polishing heads, and the two polishing stations and the load cup are positioned to allow simultaneous alignment of each of the three substrate heads with one of the two polishing stations and the load cup.

2. The polishing module of claim 1, wherein the three substrate heads are mounted on a carousel base at equal angular intervals about the carousel axis.

3. The polishing module of claim 1, wherein each of the three substrate heads is independently operable.

4. The polishing module of claim 1, wherein each of the three substrate heads has a radial movement relative to the carousel axis.

5. The polishing module of claim 4, wherein the radial movement provides a sweeping motion during polishing.

6. The polishing module of claim 1, wherein each of the two polishing stations comprises:

a platen rotatable about a central axis;

a polishing pad disposed on the platen, wherein the polishing pad has a polishing surface configured to polishing the substrate;

a polishing solution dispenser configured to deliver polishing solution on to the polishing surface; and

a conditioner assembly configured to clean and maintain the polishing pad.

7. A polishing system, comprising:

a factory interface configured to receive unpolished substrates from substrate transferring cassettes and transfer polished substrates to the substrate transferring cassettes;

a substrate transferring platform configured to receive substrates from the factory interface;

a polishing assembly configured to polishing substrates in one or more polishing steps, wherein the polishing assembly comprises a first polishing module comprises:

a first base member;

first and second polishing stations disposed on the first base member;

a first carousel supported by the first base member, wherein the first carousel comprises three substrate heads each configured to transfer a substrate and polish the substrate against the first and second polishing stations, and the first carousel is configured to simultaneously rotate the three substrate heads about a first carousel axis; and

a first load cup disposed on the first base member, wherein the first polishing station, the second polishing station and the first load cup are positioned to allow simultaneous alignment of each of the three substrate heads of the first carousel with one of the first polishing station, the second polishing station and the first load cup;

a polishing robot configured to transfer substrates from the substrate transferring platform to the polishing assembly; and

a cleaning assembly to clean polished the substrates.

8. The polishing system of claim 7, wherein the polishing assembly further comprises a second polishing module disposed against the first polishing module.

9. The polishing system of claim 8, wherein the second polishing module comprises:

a second base member;

third and fourth polishing stations disposed on the second base member;

a second carousel supported by the second base member, wherein the second carousel comprises three substrate heads each configured to transfer a substrate and polish the substrate against the third and fourth polishing stations, and the second carousel is configured to simultaneously rotate the three substrate heads about a second carousel axis; and

a second load cup disposed on the second base member, wherein the third polishing station, the fourth polishing station and the second load cup are positioned to allow simultaneous alignment of each of the three substrate heads of the second carousel with one of the third polishing station, the fourth polishing station and the second load cup,

wherein the polishing robot is configured to transfer substrates between the first and second load cups.

10. The polishing system of claim 8, wherein the second polishing module comprise:

a second base member;

third and fourth polishing stations disposed on the second base member;

a second load cup disposed on the second base member;

a first polishing arm comprising a substrate head, and is configured to pivot the substrate head to align the substrate head with the third polishing station and the second load cup;

a second polishing arm comprising a substrate head, and is configured to pivot the substrate head to align the substrate head with the fourth polishing station and the second load cup, wherein the polishing robot is configured to transfer substrates between the first and second load cups

11. The polishing system of claim 7, wherein the polishing robot is configured to transfer polished substrates to the cleaning assembly.

12. The polishing system of claim 11, wherein the cleaning assembly comprises:

a wet cleaning device;

a dry cleaning device; and

a cleaning robot configured to transfer substrates from the wet cleaning device to the dry cleaning device.

13. The polishing system of claim 12, wherein the factory interface comprises an internal robot, and the internal robot is configured to transfer substrates from the dry cleaning device to the factory interface after a dry cleaning process.

14. The polishing system of claim 7, wherein the substrate transferring platform comprises a substrate transferring belt configured to receive substrates from an internal robot of the factory interface, and the polishing robot is configured to pick substrates from the substrate transferring belt to the first load cup.

15. The polishing system of claim 7, wherein the three substrate heads of the first polishing module are mounted on the first carousel base at equal angular intervals about the first carousel axis.

16. A method for polishing a substrate, comprising:

transferring a first substrate using a substrate transferring belt towards a polishing assembly;

transferring the first substrate from the substrate transferring belt to a first load cup of the polishing assembly;

loading the first substrate from the first load cup to a first substrate head mounted on a first carousel having three polishing heads;

aligning the first substrate head with a first polishing station of the polishing assembly;

polishing the first substrate in the first polishing station;

aligning the first substrate head with the first load cup; and

unloading the first substrate from the first substrate head to the first load cup.

17. The method of claim 15, wherein aligning the first substrate head comprises:

rotating the first carousel; and

moving the first substrate head radially.

18. The method of claim 15, further comprising:

upon finishing polishing the first substrate in the first polishing station, rotating the carousel;

moving the first substrate head radially to align with a second polishing station; and

polishing the first substrate in the second polishing station.

19. The method of claim 15, further comprising:

while aligning the first substrate head with the first polishing station of the polishing assembly, simultaneously loading a second substrate on a second substrate head of the first carousel by aligning the second substrate head with the first load cup;

aligning the first substrate head with a second polishing station of the polishing assembly and simultaneously aligning the second substrate head with the first polishing station; and

polishing the first substrate in the second polishing station and simultaneously polishing the second substrate in the second polishing station;

20. The method of claim 15, further comprising:

after unloading the first substrate to the first load cup, transferring the first substrate from the first load cup to a second load cup of the polishing assembly;

loading the first substrate to a third substrate head of a second carousel having three polishing heads;

aligning the third substrate head with a third polishing station by rotating the second carousel; and

polishing the first substrate at the third polishing station.