EP1395392A1

EP1395392A1 - Improved method and apparatus for bi-directionally polishing a workpiece

Info

Publication number: EP1395392A1
Application number: EP02746526A
Authority: EP
Inventors: Homayoun Talieh; Konstantin Volodarsky; Jalal Ashjaee; Douglas W. Young; Vulf Perlov; Efrain Velazquez; Mark Henderson; Bernard M. Frey
Original assignee: ASM Nutool Inc
Current assignee: ASM Nutool Inc
Priority date: 2001-06-12
Filing date: 2002-06-12
Publication date: 2004-03-10
Also published as: JP2004528998A; KR20040025689A; TW552177B; WO2002100594A1; WO2002100594A8; KR100665748B1; CN1638919A; AU2002316240A1

Abstract

A chemical mechanical polishing apparatus and method uses a portion of a polishing pad (130) that is disposed under tension between a supply spool (160) and a receive spool (162) such that it will not degrade, a single drive system that allows for efficient bi-directional linear motion, and a mechanism that provides tension to either the supply spool or the receive spool and the other spool being locked during processing. If a new section of the polishing pad is needed, the same motor (770) that provided the tension is used to advance the polishing pad a determined amount. Further, during processing, a feedback mechanism (fig 8) is used to ensure that the tension of the polishing pad is consistently maintained.

Description

IMPROVED METHOD AND APPARATUS FOR BI-DIRECTIONALLY POLISHING A

WORKPIECE

FIELD The present invention relates to the manufacture of semiconductor wafers and more particularly to methods and apparatus for polishing a semiconductor wafer or workpiece to a high degree of planarity and uniformity at high bi-directional linear or reciprocating speeds. In particular, the invention relates to a bi-directional linear chemical mechanical polishing apparatus that includes a moving portion of a polishing belt that is disposed so that a frontside thereof does not degrade as it is supported within a support mechanism disposed between a supply spool and a receive spool. Also provided is a single drive method and system for a bidirectional linear chemical mechanical polishing apparatus, and a method and system of polishing pad tensioning in a chemical mechanical polishing apparatus.

BACKGROUND

Chemical mechanical polishing (CMP) of materials for VLSI and ULSI applications has important and broad application in the semiconductor industry. CMP is a semiconductor wafer flattening and polishing process that combines chemical removal of layers such as insulators, metals, and photoresists with mechanical polishing or buffering of a wafer layer surface. CMP is generally used to flatten surfaces during the wafer fabrication process, and is a process that provides global planarization of the wafer surface. For example, during the wafer fabrication process, CMP is often used to flatten/polish the profiles that build up in multilevel metal interconnection schemes. Achieving the desired flatness of the wafer surface must take place without contaminating the desired surface. Also, the CMP process must avoid polishing away portions of the functioning circuit parts.

Conventional systems for the chemical mechanical polishing of semiconductor wafers will now be described. One conventional CMP process requires positioning a wafer on a holder rotating about a first axis and lowered onto a polishing pad rotating in the opposite direction about a second axis. The wafer holder presses the wafer against the polishing pad during the planarization process. A polishing agent or slurry is typically applied to the polishing pad to polish the wafer. In another conventional CMP process, a wafer holder positions and presses a wafer against a belt-shaped polishing pad while the pad is moved continuously in the same linear direction relative to the wafer. The so-called belt-shaped polishing pad is movable in one continuous path during this polishing process. These conventional polishing processes may further include a conditioning station positioned in the path of the polishing pad for conditioning the pad during polishing. Factors that need to be controlled to achieve the desired flatness and planarity include polishing time, pressure between the wafer and pad, speed of rotation, slurry particle size, slurry feed rate, the chemistry of the slurry, and pad material.

Although the CMP processes described above are widely used and accepted in the semiconductor industry, problems remain. For instance, there remains a problem of predicting and controlling the rate and uniformity at which the process will remove materials from the substrate. As a result, CMP is a labor intensive and expensive process because the thickness and uniformity of the layers on the substrate surface must be constantly monitored to prevent overpolishing or inconsistent polishing of the wafer surface.

U.S. Patent No. 6,103,628, assigned to the assignee of the invention, describes a reverse linear chemical mechanical polisher, also referred to as bi-directional linear chemical mechanical polisher, that operates to use a bi-directional linear motion to perform chemical mechanical polishing. In use, a rotating wafer carrier within a polishing region holds the wafer being polished.

While advantageous, a more efficient and inexpensive method and apparatus for polishing a semiconductor wafer is still needed, including a system that does not degrade the frontside of the wafer, a system that provides a for a more efficient drive system that creates the reverse linear (or bi-directional linear) motion, and a system that provides for more efficient tensioning of the polishing belt.

SUMMARY

The invention overcomes the identified limitations and provides an improved method and apparatus for bi-directionally polishing a workpiece. Consequently, a number of advantages may be obtained using the invention including the following.

An advantage of the invention is to provide methods and apparatus that polish a semiconductor wafer with uniform planarity. Another advantage of the invention is to provide methods and apparatus that polish a semiconductor wafer with a pad having high bi-directional linear or reciprocating speeds.

Another advantage of the invention is to provide a polishing method and system that provides a "fresh" polishing pad to the wafer polishing area, thereby improving polishing efficiency and yield.

A further advantage of the invention is to provide a drive system that provides incremental movement for a polishing pad that is diposed between a supply spool and a receive spool, and that operates upon a portion of the polishing pad disposed between the supply spool and the receive spool in such a manner that does not degrade the frontside of the polishing pad by the support mechanism used to hold the portion of the polishing pad, such that the lifetime of the polishing pad is maximized.

Another advantage of the invention is the provision for a single casting that houses the polishing pad, including the supply spool, the receive spool, and pad path rollers.

These and other advantages of the invention, among others, either singly or in combination, are obtained by providing methods and apparatus that polish a wafer with a pad having high bi-directional linear speeds. The invention includes a polishing pad or belt secured to a mechanism that allows the pad or belt to move in a reciprocating manner, i.e. in both forward and reverse directions, at high speeds. The constant bi-directional movement of the polishing pad or belt as it polishes the wafer provides superior planarity and uniformity across the wafer surface. When a fresh portion of the pad is required, as well as during polishing with a moving portion of the pad, the pad is moved through a drive system containing rollers, such that the rollers touch a back side of the pad, thereby eliminating sources of friction other than the wafer that is being polished, and maximizing the lifetime of the polishing pad. In one aspect of the invention, the rollers touch only the back side of the pad so that the rollers do degrade the pad surface.

In another embodiment , the invention provides the above advantages with a method and apparatus for producing bi-directional linear polishing that uses a flexible pad. In one aspect, a horizontal drive assembly moves a horizontal slide member that is horizontally moveable over rails attached to a single casting. Openings within the casting exist for the inclusion of the supply spool, the receive spool and the pad path rollers. A drive assembly translates the rotational movement of a motor into the horizontal bi-directional linear movement of the horizontal slide member. With the polishing pad properly locked in position, preferably being attached between the supply spool and the receive spool, horizontal bi-directional linear movement of the horizontal slide member creates a corresponding horizontal bi-directional linear movement of a portion of the polishing pad. Thus, the portion of the polishing pad disposed within a polishing area of the chemical mechanical polishing apparatus can polish a top front surface of a wafer using the bi-directional linear movement of the portion of the polishing pad.

In yet another embodiment, the invention provides a portion of the polishing pad is disposed under tension between a supply spool and a receive spool, with a motor providing the tension to either the supply spool or the receive spool and the other spool being locked during processing. If a new section of the polishing pad is needed, the same motor that provided the tension, if connected to the receive spool, is used to advance the polishing pad a determined amount. Further, during processing, a feedback mechanism is used to ensure that the tension of the polishing pad is consistently maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other advantages of the invention will become apparent and more readily appreciated from the following detailed description of the presently preferred exemplary embodiment of the invention taken in conjunction with the accompanying drawings, of which:

Figure 1 illustrates a bi-directional linear polisher according to the invention; Figure 2 illustrates a simplified illustration of a drive mechanism for providing a fresh portion of the polishing pad according to the invention; and

Figures 3 A and 4B illustrate side and cross-sectional views of a polishing apparatus that includes a drive mechanism for providing a fresh portion of the polishing pad according to the invention. Figure 4 illustrates a perspective view of a pad drive system that includes a horizontal slide member that is horizontally moveable over a stationary casting using drive components according to the invention;

Figure 5 illustrates a polishing pad path through components of the casting that provide for a processing area in which bi-directional linear motion of the polishing pad results; Figure 6 illustrates a side view of a horizontal slide member and the drive system according to the invention; Figures 7A and 7B illustrate a tensioning and incrementing mechanism according to the invention;

Figure 8 illustrates the controller used to control the tensioning and incrementing mechanism according to the invention; and Figure 9 illustrates a flowchart of preferred operation using the tensioning and incrementing mechanism according to the invention.

DETAILED DESCRIPTION

The invention is directed to CMP methods and apparatus that can operate at high bi- directional linear pad or reciprocating speeds and a reduced foot-print. The high bi-directional linear pad speeds optimize planarity efficiency while the reduced foot-print reduces the cost of the polishing station. Further, because the polishing pad is adapted to travel in bi-directional linear directions, this reduces the pad glazing effect, which is a common problem in conventional CMP polishers. Because the pad travels in bi-directional linear directions, the pad (or pad attached to a carrier) is substantially self-conditioning.

Figure 1 illustrates a processing area 120 for a bi-directional linear polishing apparatus. A portion of the bi-directional linearly moving pad 130 for polishing a front wafer surface 112 of a wafer 110 within a processing area is driven by a drive mechanism. The wafer 110 is held in place by a wafer carrier 140 and can also rotate during a polishing operation as described herein. Below the pad 130 is a platen support 150. During operation, due to a combination of tensioning of the pad 130 and the emission of a fluid, such as air, water, or a combination of different fluids from openings 154 disposed in the top surface 152 of the platen support 150, the bi-linearly moving portion of the pad 130 is supported above the platen support 150 in the processing area, such that a frontside 132 of the pad 130 contacts the front surface 112 of the wafer 110, and the backside 134 of the pad 130 levitates over the top surface 152 of the platen support 150. While the portion of the pad 130 within the processing area moves in a bi-linear manner (see reference number 136), the two ends of the pad 130 are preferably connected to source and target spools 160 and 162 illustrated in Figure 5, respectively, allowing for incremental portions of the pad 130 to be placed into and then taken out of the processing area. Further, during operation, various polishing agents without abrasive particles or slurries with abrasive particles can be introduced, depending upon the type of pad 130 and the desired type of polishing, using nozzles 180. For example, the polishing pad 130 can contain abrasives embedded in the frontside 132, and can be used with polishing agents but not a slurry being introduced, or with a polishing pad 130 that does not contain such embedded abrasives instead used with a slurry, or can use some other combination of pad, slurry and/or polishing agents. The polishing agent or slurry may include a chemical that oxidizes the material that is then mechanically removed from the wafer. A polishing agent or slurry that contains colloidal silica, fumed silica, alumina particles etc., is generally used with an abrasive or non-abrasive pad. As a result, high profiles on the wafer surface are removed until an extremely flat surface is achieved.

While the polishing pad can have differences in terms of whether it contains abrasives or not, any polishing pad 130 according to the invention needs to be sufficiently flexible and light so that a variable fluid flow from various openings 154 on the platen support can affect the polishing profile at various locations on the wafer. Further, it is preferable that the pad 130 is made from a single body material, which may or may not have abrasives impregnated therein. By single body material is meant a single layer of material, or, if more than one layer is introduced, maintains flexibility such as obtained by a thin polymeric material as described herein. An example of a polishing pad that contains these characteristics is the fixed abrasive pad such as MWR66 marketed by 3M company that is 6.7 mils (0.0067 inches) thick and has a density of 1.18 g/cm³. Such polishing pads are made of a flexible material, such as a polymer, that are typically within the range of only 4-15 mils thick. Therefore, fluid that is ejected from the openings 154 on the platen support 150 can vary by less than 1 psi and significantly impact the amount of polishing that will occur on the front face 112 of the wafer 110 that is being polished, as explained further hereinafter. With respect to the pad 130, the environment that the pad 130 is used in, such as whether a linear, bi -linear, or non-constant velocity environment will allow other pads to be used, although not necessarily with the same effectiveness. It has been determined, further, that pads having a construction that has a low weight per cm² of the pad, such as less than 0.5 g/cm², coupled with the type of flexibility that a polymeric pad achieves, also can be acceptable.

Another consideration with respect to the pad 130 is its width with respect to the diameter of the wafer 110 being polished, which width can substantially correspond to the width of the wafer 110, or be greater or less than the width of the wafer 110. As will also be noted hereinafter, the pad 130 is preferably substantially optically transparent at some wavelength, so that a continuous pad 130, without any cut-out windows, can allow for detection of the removal of a material layer (end point detection) from the front surface 112 of the wafer 110 that is being polished, and the implementation of a feedback loop based upon the detected signals in order to ensure that the polishing that is performed results in a wafer 110 that has all of its various regions polished to the desired extent.

The platen support 150 is made of a hard and machineable material, such as titanium, stainless steel or hard polymeric material. The machineable material allows formation of the openings 154, as well as channels that allow the fluid to be transmitted through the platen support 150 to the openings 154. With the fluid that is ejected from the openings 154, the platen support 150 is capable of levitating the pad. In operation, the platen support 50 will provide for the ejection of a fluid medium, preferably air, but water or some other fluid can also be used. This ejected fluid will thus cause the bi-linearly moving pad 130 to levitate above the platen support 150 and pushed against the wafer surface when chemical mechanical polishing is being performed.

The support plate for supporting the polishing pad will now be described. The polishing pad is held against the wafer surface with the support of the support plate, which may be coated with a magnetic film. The backside of the support material to which the polishing pad is attached may also be coated with a magnetic film, thus causing the polishing pad to levitate off the support plate while it moves at a desired speed. It should be understood that other conventional methods can be used to levitate the polishing pad off the support plate while it polishes the wafer surface, such as air, magnetic, lubricant, and/or other suitable liquids.

Figure 2 provides a simplified illustration of a drive mechanism for providing a fresh portion of the polishing pad according to the invention, which provides for a translation of rotational motion to linear up and down motion. As shown, rotation of an axle, for example illustrated as axle 231 associated with motor 232 will result in rotation of two drive mounts 238 and 240. To each of these drive mounts is attached some motion translation mechanism 242 and 244, respectively, which are roughly 180 degrees out of phase as attached to the drive mounts 238 and 240. While shown is a slotted adapter for translating the rotational movement to linear movement, the mechanism can also be constructed in a number of other ways, for example, using connecting rods. These mechanisms are supports to which the different end portions 210a and 210b of the polishing belt 210 are attached, respectively. Moreover, the polishing belt is preferably supported in position, and in particular an appropriate position within a polishing area (not shown), by a support mechanism, shown for example as rollers 212, from a backside of the polishing belt. Rotation of the drive mounts 238 and 240 results in the complementary reciprocating linear motion, such that when drive mount 238 is moving in an upward linear direction, drive mount 240 is moving in a downward linear direction. Thus, with the polishing belt 210 properly positioned between a supply spool and a receive spool (not shown), this movement of the drive mounts 238 and 240 results in bi-directional linear movement according to the invention. Since the support mechanism supports the polishing belt from the backside, and the polishing side (i.e. front side) does not contact the support mechanism, sources of friction other than the wafer that is being polished are minimized from the polishing side of the pad. Consequently, the polishing side of the pad is not degraded by the support mechanism.

Figures 3A and 3B illustrate side and cross sectional views, respectively, of a specific implementation of the drive mechanism described above with respect to Figure 7 in accordance with the invention.

The polishing apparatus 300 includes a driving mechanism having a bi-directional linear, or reverse linear, polishing belt 310 for polishing a wafer (not shown) that is supported by the wafer housing (not shown). A processing area 316 has a section of the polishing belt 310 that is supported by a platen 323, which platen 323 is capable of providing "gimbaling" action for leveling/suspending the section of the polishing belt 310 above it. In addition, an air or magnetic bearing may be positioned underneath the processing area 316 to control the pressure between the section of the polishing belt 310 and the wafer surface during the polishing process.

Besides the processing area 316, the polishing apparatus 300 includes in its top portion a supply spool 311 , a receiving spool 315, and a polishing belt support mechanism 312, shown as rollers 312a, 312b, 312c, 312d, 312e, 312f, 312g, 312h. Rollers 312a, 312d, 312e and 312h are fixed in position, whereas roller pairs 312b and 312c, as well as 312f and 312g, are attached to respective drive supports 320 and 322, which are each moved in a complementary reciprocating linear motion that is obtained using a driving mechanism 330. The drive mechanism includes a motor 332, which, via a belt 334 drives axle 336, which in turn will rotate each of the two drive mounts 338 and 340, which in turn provide movement to the elbows 342 and 344, respectively. Each end of the elbows 342 and 344 can rotate about the respective pivot points such as pivot points 342a and 342b illustrated in Figure 3B.

With the polishing belt 310 fed between the supply spool 311 and the receiving spool 315, it is apparent that a frontside of the polishing belt 310 will only contact a surface of the wafer or workpiece being polished, while the backside of the polishing belt will be in contact with various surfaces to ensure alignment, including the various rollers 312 described above.

As is apparent, rotation of the axle associated with motor 332 will cause rotation of the belt 334 and the corresponding axle 336, and rotation of the two drive mounts 338 and 340. To each of these drive mounts is attached one of the elbows 342 and 344, which attachments are preferably 180 degrees out of phase. Rotation of the drive mounts 338 and 340 results in the complementary reciprocating linear motion, such that when drive support 320 is moving in an upward linear direction, drive support 322 is moving in a downward linear direction. Thus, with the polishing belt 310 properly positioned between the supply spool 311 and the receive spool 315 and attached, via roller pairs 312b, 312c and 312f, 312g to the drive supports 320 and 322, respectively, this movement of the drive supports 320 and 322 will result in the bi-directional linear movement according to the invention.

Advancing the polishing belt 310, whether that advancement takes place in incremental step portion movement or in larger step portion movement, whether that movement is while the polishing belt 310 is polishing a wafer or between times that polishing belt 310 is polishing a wafer, will allow for a new portion of the polishing belt 310 to come off of the supply spool 311 and a previously used portion to be taken up by the receiving spool 315. The mechanism used to implement this movement is preferably a conventional clutch mechanism that is connected to the supply spool 311, which is used to adjust the tension of the polishing belt 310 between the supply spool 311 and the receiving spool 315. After the section of the polishing belt 310 is used to polish one or more wafers in the processing area, a new section of the polishing belt 310 is fed to the processing area in the manner described above. In this manner, after one section of the polishing belt 310 is worn out, damaged, etc., the new section can be used. Consequently, using the present invention, all or most sections of the polishing belt 310 in the supply spool 311 will be used. It is noted that the feeding of a new section of the polishing belt 310 to the processing area can occur in between times that polishing of the wafers is occurring, or the polishing belt 310 can gradually be advanced, such that the new section of the polishing belt 310 is a new portion, along with a portions that have been previously used, with that portion of the polishing belt 310 that is within the polishing area and closest to the receiving spool 315 having been used the most, and that portion of the polishing belt 310 that is within the polishing area and closest to the supply spool 311 having been used the least.

A second conventional motor (not shown) is connected to the receiving spool 315 for rotating the same so that sections of the polishing belt 310 can be pulled from the supply spool 311 to the receiving spool 315. For example, when the second motor is activated and the clutch resistance is properly adjusted, the second motor rotates the receiving spool 311 in a manner such that sections or portions of the polishing belt 310 are received therein. In a similar manner, the tension of the polishing belt 310 between the supply spool 311 and receiving spool 315 can be adjusted by providing the appropriate motor torque and clutch resistance. This technique can be used to provide the proper contact pressure between the polishing belt 310 and the wafer surface in the processing area 316. Figures 4 through 9 depict an improved drive system 400 that provides highly reliable smooth and continuous bi-linear reciprocating movement of the portion of the polishing pad. Referring to Figure 5, a path 536 that the polishing pad 530 travels within the pad drive system 400 between the supply spool 560 and the receive spool 562 is illustrated. As shown, from the supply spool 560 and alignment roller 514B the path 536 includes passing through top 528C and then bottom 528D right slide rollers of the slide member 520, and then over each of rollers 512A, 512B, 512C and 512D in a rectangularly shaped path and then around each of the bottom 528B and then top 528A left slide rollers of the slide member 520, and then to the alignment roller 514A and receive spool 562. As is apparent from Figure 5, and with reference to the points "Al, A2, Bl, B2, and C, with the polishing pad 530 properly locked in position, preferably being attached between a supply spool 560 and the receive spool 562, horizontal bi-directional linear movement of the horizontal slide member 520 creates a corresponding horizontal bi-directional linear movement of a portion of the polishing pad. Specifically, for example, as the horizontal slide member 520 moves from right to left from position PI to position P2, the point Al on the pad 530 will remain in the same position relative to the receive spool 562, but the point A2 will have moved through the left side rollers 528 A and 528B of the horizontal slide member 520. Similarly, the point Bl on the pad 530 will remain in the same position relative to the supply spool 560, and the point B2 will have moved through the right side rollers 528D and 528C of the horizontal slide member 520. As is apparent, by this movement, the point C will have moved linearly through the processing area. It is noted that the point C will move twice as far horizontally as compared to the horizontal movement of the horizontal slide member 520. Movement of the horizontal slide member 520 in the opposite direction will cause the point C of the polishing pad 530 to also move in the opposite direction. Thus, the portion of the polishing pad disposed within a polishing area (point C) of the chemical mechanical polishing apparatus can polish a top front surface of a wafer using the bi-directional linear movement of the portion of the polishing pad 530. With the path 536 and the bi-linear pad movement mechanism having been described, a further description of the components within the path 536, and the horizontal movement drive assembly 550 associated therewith, will now be provided.

As additionally illustrated in Figures 4 and 6, the horizontal slide member 520 is horizontally moveable over rails 540. The rails 540 are attached to a casting 510, made of a metal such as coated aluminum, which casting also has all of the other pad path generating components attached thereto as well. Thus, various openings within the casting 510 exist for the inclusion of these pad path components, including the supply spool 560 and the receive spool 562 (which are each attached to a spool pin associated therewith), as well as each of rollers 512A, 512B, 512C, 512D, 514A and 514B, as well as a large opening for a roller housing 521 and pin connection piece 522A that connect together the sidepieces 522B1 and 522B2 of the horizontal slide member 520. The rails 540, one on each side of the casting 510, provide a surface for mounting rails 540 on which the horizontal slide member 520 will move. As illustrated in Figure 6, the horizontal slide member 520 is mounted on the rails 540 using carriage members 526. The carriage members 526 moveably hold the wafer in positions above and below the rail and can be used to reduce friction between the rails 540 and the horizontal slide member 520. The carriage members 526 may include sliding elements such as metal balls or cylinders (not shown) to facilitate sliding action of the horizontal sliding member 520.

With respect to the horizontal slide member 520, as illustrated in Figures 4 and 6, a support structure 522 is shaped with side-walls 522B1 and 522B2 with connecting piece 522A attached between them. The carrier members 526 are attached to the inner sides of the side-walls 522B1, 522B2. Further, the roller housing 521 is shaped with sidepieces 521 Al and 521 A2, with a connecting piece 52 IB between them. The roller housing 521 is supported by the support structure 522. In this respect, side pieces 521 Al and 521 A2 of the roller housing are attached to the side walls 522B1, 522B2 of the support structure 522, using support pieces 523. Attached between the two side pieces 521 Al and 521 A2, in the vicinity of the connecting piece 521B, are four rollers 528 A-D, with left side rollers 528 A-B on one side of the connecting piece 52 IB and right side rollers 528C-D on the other side of the connecting piece 52 IB.

Furthermore, a pin 530 is downwardly disposed from the pin connection piece 522A as shown in Figure 6, which pin 530 will connect to a link 564 associated with the horizontal drive assembly 550, described hereinafter. The horizontal drive assembly 550 will cause horizontal bid-directional linear movement of the pin 530, and therefore the horizontal bid-directional linear movement of entire horizontal slide member 520 along the rails 540.

The horizontal drive assembly 550, as shown in Figure 5, is comprised of a motor 552 that will rotate shaft 554. Shaft 554 is connected to transmission assembly 556 that translates the rotational movement of the shaft 554 into the horizontal bi-directional linear movement of the horizontal slide member 520. In a preferred embodiment the transmission assembly 556 contains a gearbox 558 that translates the horizontal rotational movement of shaft 554 into a vertical rotational movement of shaft 560. Attached to shaft 560 is a crank 562 to which one end 564A of the link 564 is attached, with the other end 564B of the link 564 being attached to the pin 530, thereby allowing relative rotational movement of the pin 530 within the other end 564B of the link 564, which when occurring will also result in the horizontal bi-linear movement of the pin 530.

Thus, operation of the horizontal drive assembly 550 will result in the bi-directional linear movement of the horizontal slide member 520, and the corresponding horizontal bidirectional linear movement of a portion of the polishing pad 530 within the processing area. During processing the polishing pad can be locked in position between the supply spool

560 and the receive spool 562. As such, while a portion of the pad 530 within the processing area moves in the horizontal bi-directional linear manner, the pad can also be unlocked so that another portion of the polishing pad will move within the processing area, allowing incremental portions of the pad to be placed into and then taken out of the processing area. While have the pad 530 locked in position at both the supply spool 560 and the receive spool 562 will work, it has been found that more effective results can be achieved using a tensioning mechanism at one end of the portion of pad 530 in cooperation with the drive system. In particular, as illustrated in Figures 7A and 7B, a processing system is shown with the parts needed for the present discussion, which includes a horizontal slide member 720 that includes rollers 728 A and 728B that are connected together using an connector piece 722. The polishing pad 530 travels in a pad path 536 that is similar to that described previously with reference to Figure 5, from the supply spool 760 and alignment roller 714B, through the horizontal slide member roller 728B, and then around both rollers 712B and 712A, to the horizontal slide member roller 728A, and then to the receive spool 762 via the alignment roller 714A. It should be noted, however, that this simplified version is not preferred, since a portion of the frontside of the pad 530 will touch the rollers 728A and 728B.

Further, as shown in Figures 7A and 7B, a belt 772 is connected between a tensioning and incrementing motor 770, which is referred to as the motor 770 hereinafter, and the receive spool 762. Further, a lock mechanism 780, such as a clamp mechanism, is illustrated. In this embodiment, tensioning of the pad may be obtained by locking the supply spool 760 using the lock mechanism 780 and activating the motor 770 with a predetermined torque value to rotate the receive spool 762 which is connected to the motor 770 through the belt 772. Further, incrementing of the pad is obtained by unlocking the lock mechanism to release the supply spool 760, and rotating the motor 770, preferably at a low rpm, until for example a used section of the pad is taken up by the receive spool 762, and a new pad section is brought over the processing area.

Figure 8 depicts greater detail of the control system for controlling the tensioning and incrementing motor 770 and the lock mechanism 780. As shown, power for the motor 770 and a controller 820 is provided by power source 810, which provides appropriate power along line 814 to a driver 824 and likely a different appropriate power along line 812 to controller 820. Controller 820 includes a computer or microcontroller of some type, as is known in the art.

Further, line 822 from the controller inputs the predetermined torque value to the motor control unit 804 as a TORQUE signal, specifically to torque control unit 826. The predetermined torque value for the motor 770 may be a torque value that is about 10 % less than the rated torque value of the lock mechanism 780. The line 823 from the torque control unit inputs the TORQUE signal to the driver 824. Line 816 returns the TORQUE signal that is received from the driver 824 to the controller for feed-back or self-check purposes. If self-check is not desired, the line 816 is removed. As will be described hereinafter, the TORQUE signal is used to maintain the tension on the receive spool 762 at a desired level during processing. The driver 824, through the line 828a, applies this torque value to the motor 770 as electrical current.

If the pad needs to be incremented, however, with an appropriate signal from the controller, the motor 770 is rotated, preferably at a low rpm, and the pad is advanced. As the motor rotates, it generates predetermined number of encoder pulses per revolution. The encoder pulses generated by the motor 770 are fed back to the driver 824 through the line 828b and then from the driver 824 to the controller 820 through the line 828c. By counting the pulses, the controller 820 tracks the position of the pad, as it is advanced by the motor 770. In one example, a single revolution of the motor 770 advances the pad 280 millimeters. An exemplary motor maybe Model no. SG255SA-GA05ACC which is available from Yaskawa Electric Co., Tokyo, Japan. In this particular example, the motor 770 generates 8192 pulses per revolution. These pulses are sent to the driver serially. However, encoder pulses are typically ignored by the controller when performing tensioning, because the motor 770 may try to rotate at a certain speed, but of course it will not be able to move since pad is constrained by the lock mechanism 280 on the supply spool.

Upon receipt of process sequence commands and external signals, such as the TORQUE signal discussed above, controller 820 will generate control signals along line 822 that are used by the motor control unit 804 to control the motor 770. In particular, the signals generated include an ON/OFF signal, as well as a TENSION signal that is used to supply the motor control unit 804 with an indication of the proper amount of power to supply to the motor 770 in order to achieve the desired tension on the receive spool 562 during processing. Controller 820 will also generate a BRAKE signal along line 830, which preferably passes through a relay 832 to the lock mechanism 780, which is preferably implemented as an electromagnetic clamp brake that is used to lock the supply spool 560 in position. A monitor 840 and a user-input device 850 such as a keyboard are also preferably connected to the controller 820.

The motor control unit 804 includes a driver 824 and a torque adjustment unit 826. Power supplied to the driver 824 is varied in dependence upon a signal that is generated by the torque adjustment unit 826. Operation of the tensioning and incrementing of the portion of the pad 530 according to the invention will now be further described with reference to the flowchart illustrated in Figure 9, with reference to the other Figures discussed above.

As illustrated, during processing, initially in step 910, the controller 820 provides an OFF signal to both the motor control unit 804 and the lock mechanism 780. This causes both the supply spool 760 and the receive spool 762 to rotate freely, thereby allowing the initial threading of the pad 530 through the pad path 536 as described above with reference to Figure 7A. Once threaded and processing is to occur, step 920 follows, at which time controller 820 provides an ON signal to the lock mechanism 780, followed by a TENSION signal to the motor control unit 804, which TENSION signal turns on the motor 770 and applies tension to the receive spool 762. Thus, the supply spool 760 becomes locked, and the receive spool 762 is held under tension, thereby appropriately tensioning the entire portion of the pad 530 therebetween, including that portion of the pad 530 that is in the processing area 120 illustrated in Figure 1.

Thereafter, step 930 is begun and processing will occur. During processing, the controller 820 will initiate the bi-directional linear movement of the pad 530 using the pad drive system 500 discussed above with reference to Figure 5 for example. During processing using a specific portion of the pad 530, typically some number of wafers 110 can be processed, which may result in the turning on and off of the pad drive system 500.

At some point, however, the portion of the pad 530 used for polishing will need to be replaced, and another portion of pad 530 provided. While an entirely new portion of pad 530 will be described as being provided, it is anticipated that incremental or continuous portions can also be provided. When any new portion of pad 530 is needed from the supply spool 760, the same operation will apply. In particular, the controller 820 will first provide in step 930 an OFF signal to the motor control unit to signal that the motor 770 should be turned off. Thereafter follows step 940, in which an OFF signal will also be provided to the lock mechanism 780, thereby turning off the brake and unlocking the supply spool 760. Step 960 then follows, in which the controller 820 signals to the motor control unit 804 to increment the pad 530 some specified amount, which amount will correspond to the linear distance the pad 530 is desired to move. Upon this signal, the motor control unit 804 turns on the motor 770 and advances the pad by rotating the receive spool 762. As previously mentioned this specific amount that the pad is incremented may be determined through the encoder pulses generated by the rotating motor 770. Once the pad advancement occurs, step 920 is then initiated again, so that the supply spool 760 can be locked and the receive spool tensioned as described above.

The description provided above illustrates a preferred manner of providing tension during processing for the portion of the pad 530 that is in the processing area, as well as the incrementing of the pad 530, using the same motor 770. It is understood that although described as tensioning the receive spool 762 and locking the supply spool 760 during processing, that tensioning the supply spool 760 and locking the receive spool 762 during processing is another manner of implementing the invention.

While the tensioning and incrementing is preferably accomplished using the single motor 770, it is understood that if two motors, one attached to the receive spool and the other to the supply spool, that a variety of arrangements for tensioning and incrementing would also exist.

It is understood that the second embodiments of the invention with receiving and supply spools can use various numbers of rollers, various types of drive mechanisms, and the like, which cooperate to provide the bi-directional linear or reciprocating motion and is intended to be within the spirit and scope of the invention. In addition, other similar components and devices may be substituted for the ones described above.

In addition, the layout or geometry of the polishing pad/belt with respect to the wafer as illustrated in the first and second embodiments can be changed from those illustrated herein to other positions. For example, one can position the polishing pad/belt above the wafer, position the polishing pad/belt vertically with respect to the wafer, etc.

It is to be understood that in the foregoing discussion and appended claims, the terms "wafer surface" and "surface of the wafer" include, but are not limited to, the surface of the wafer prior to processing and the surface of any layer formed on the wafer, including conductors, oxidized metals, oxides, spin-on glass, ceramics, etc. Although various preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and/or substitutions are possible without departing from the scope and spirit of the invention as disclosed in the claims.

The subject matter of the invention includes at least the following features. 1. A method of providing bi-directional linear polishing comprising the steps of: providing a polishing belt on a support mechanism between a supply area and a receive area, the polishing belt having a first end and a second end and a polishing side and a backside, such that the first end initially comes off the supply area and is connected to the receive area and the second end remains connected to the supply area; polishing by bi-directionally linearly moving a portion of the polishing belt within a polishing area; advancing the polishing belt to obtain another portion that will be used for polishing, wherein the step of advancing advances the polishing belt over the support mechanism such that the polishing side of the polishing belt is not degraded by the support mechanism; polishing by bi-directionally linearly moving the another portion of the polishing belt; and repeating the steps of advancing and polishing using another portion. 2. A method according to above wherein the step of advancing advances the polishing belt over a plurality of rollers within the support mechanism that support the polishing belt from the backside of the polishing belt and not the polishing side of the polishing belt.

3. A method according to above further including the steps of: introducing a first workpiece to the polishing area prior to polishing using the portion of the polishing belt; removing the first workpiece when polishing of the first workpiece is completed; and introducing a second workpiece to the polishing area prior to polishing using the another portion of the polishing belt.

4. A method according to above wherein during the step of polishing, there is also included the step of tensioning the portion of the polishing belt within the polishing area. 5. A method according to above wherein the step of tensioning uses the plurality of rollers disposed between the supply area and the receive area.

6. A method according to above wherein the steps of polishing with the portion of the polishing belt includes the steps of: causing a first plurality of rollers to reciprocate vertically, thereby causing the portion to move bi-directionally linearly; causing a second plurality of rollers to rotate about a stationary axis, thereby providing the polishing area therebetween; and maintaining contact between a workpiece with the portion of the polishing belt within the polishing area.

7. A method according to above wherein the steps of causing are implemented by translating rotational motion to linear motion using a drive system. 8. A method according to above wherein the steps of polishing with the another portion of the polishing belt includes the steps of: causing the first plurality of rollers to reciprocate vertically, thereby causing the another portion to move bi-directionally linearly; causing the second plurality of rollers to rotate about the stationary axis, thereby providing the polishing area therebetween; and maintaining contact between another workpiece with the another portion of the polishing belt within the polishing area. 9. A method according to above wherein the steps of causing during the steps of polishing with the portion and the steps of causing during the steps of polishing with the another portion are implemented by translating rotational motion to linear motion using a drive system.

10. A method according to above wherein the step of causing the first plurality of rollers to reciprocate vertically results in at least one roller moving vertically in one direction when at least another roller is moving vertically in an opposite direction.

11. A method according to above wherein the step of advancing gradually advances to the another portion such that there is an overlap between the portion and the another portion.

12. A method according to above wherein during the step of advancing a previously used portion is received into the receive area and a new portion comes off the supply area. 13. A method according to above wherein the steps of polishing perform abrasive polishing.

14. A method according to above wherein the steps of polishing perform non-abrasive polishing.

15. A method according to above wherein, during the steps of polishing, there is simultaneously occurring a step of providing a force to the backside of the polishing belt within the polishing area.

16. A method according to above wherein the step of providing the force applies air.

17. A method according to above wherein the steps of polishing use a polishing belt that has a width greater than a width of a workpiece being operated upon. 18. A method according to above wherein the steps of polishing use a polishing belt that has a width less than a width of a workpiece being operated upon.

19. A method according to above wherein the step of advancing gradually advances to the another portion such that there is an overlap between the portion and the another portion.

20. A method according to above wherein during the step of advancing a previously used portion is received into the receive area and a new portion comes off the supply area. 21. A method according to above wherein the steps of polishing perform abrasive polishing.

22. A method according to above wherein the steps of polishing perform non-abrasive polishing. 23. A method according to above wherein, during the steps of polishing, there is simultaneously occurring a step of providing a force to the backside of the polishing belt within the polishing area.

24. A method according to above wherein the step of providing the force applies air.

25. A method according to above wherein the steps of polishing use a polishing belt that has a width greater than a width of a workpiece being operated upon.

26. A method according to above wherein the steps of polishing use a polishing belt that has a width less than a width of a workpiece being operated upon.

27. A polishing apparatus adapted to polish using a polishing belt having a first end and a second end and a polishing side and a backside, comprising: a receive area to which the first end of the polishing belt can be connected; a supply area to which the second end of the polishing belt can be connected; a support structure that provides a path for the polishing belt to travel between the receive area and the supply area, such that a workpiece processing area exists along the path, the support structure being constructed such that the polishing side of the polishing belt is not used by the support structure to support the polishing belt; a first drive mechanism that is capable of bi-directionally linearly polishing by bi-directionally linearly moving a portion of the polishing belt within the processing area; and a second drive mechanism that provides for advancing the polishing belt, such that another portion of the polishing belt can be located within the processing area and used for bi-directional linearly polishing by bi- directionally linearly moving the another portion of the polishing belt within the processing area. 28. An apparatus according to above further including a tensioning mechanism to tension the portion of the polishing belt within the polishing area.

29. An apparatus according to above wherein the tensioning mechanism is a clutch.

30. An apparatus according to above wherein the support structure includes a plurality of rollers disposed on a polishing belt path that exists between the supply area and the receive area and wherein the polishing belt advances of the plurality of rollers so that only the backside of the polishing belt and not the polishing side of the polishing belt contacts the plurality of rollers. 31. An apparatus according to above wherein the plurality of rollers includes: a first plurality of rollers that reciprocate vertically, thereby causing the portion to move bi- directionally linearly; and a second plurality of rollers that rotate about a stationary axis, thereby providing the polishing area therebetween. 32. An apparatus according to above wherein the first plurality of rollers includes at least one roller that moves vertically in one direction when at least another roller moves vertically in an opposite direction.

33. An apparatus according to above wherein the first drive mechanism translates rotational motion to linear motion at two different end portions of the polishing belt. 34. An apparatus according to above wherein the first drive mechanism includes: a motor; at least one axle which can be rotated using the motor; a pair of drive mounts connected to the at least one axle; and a pair of polishing belt attachment mechanism such that each polishing belt attachment mechanism is coupled between an end portion of the polishing belt and a different one of the pair of drive mounts and wherein using the motor causes rotation of the at least one axle, rotation of the pair of drive mounts and reciprocating linear motion of pair of polishing belt attachment mechanisms and the end portions of the polishing belt.

35. A method according to above wherein: the step of polishing by bi-directionally moving the portion of the polishing belt within the polishing area moves the portion of the polishing belt over the support mechanism so that only the backside of the polishing belt contacts the support mechanism; and the step of polishing by bi-directionally moving the another portion of the polishing belt within the polishing area moves the another portion of the polishing belt over the support mechanism so that only the backside of the polishing belt contacts the support mechanism.

36. A method apparatus according to above wherein the steps of providing and advancing the polishing belt each cause the first end and the second end of the polishing belt to be positioned so that the portion and the another portion, respectively, can be moved during the steps of polishing.

37. A method according to above wherein during the step of polishing, there is also included the step of tensioning the portion of the polishing belt within the polishing area. 38. A method according to above wherein, during the steps of polishing, the first end and the second end of the polishing belt remain stationary within the supply area and the receive area, respectively.

39. A method according to above wherein during the step of polishing, there is also included the step of tensioning the portion of the polishing belt within the polishing area.

40. A method according to above wherein the steps of polishing each further include the step of levitating a certain portion of the polishing belt within the polishing area over a platen to cause contact, and thereby the polishing, between the frontside of the polishing belt and a frontside of a workpiece being polished. 41. A method according to above wherein the steps of polishing each further include the step of levitating a certain portion of the polishing belt within the polishing area over a platen to cause contact, and thereby the polishing, between the frontside of the polishing belt and a frontside of a workpiece being polished.

42. An apparatus according to above wherein the support structure supports the portion of the polishing belt so that the polishing side of the polishing belt is not used by the support structure to support the portion of the polishing belt while the portion of the polishing belt is being used to bi-directionally linearly polish within the processing area.

43. An apparatus according to above wherein the receive area is adapted to position the first end of the polishing belt and the supply area is adapted to position the second end of the polishing belt so that so that the portion and the another portion, respectively, can be bi- directionally linearly moved by the first drive mechanism to bi-directionally linearly polish within the processing area.

44. An apparatus according to above wherein the second drive mechanism further provides for tensioning of the portion and the another portion of the polishing belt within the processing area when the portion and the another portion, respectively, are within the processing area.

45. An apparatus according to above wherein the second drive mechanism further provides for tensioning of the portion and the another portion of the polishing belt within the processing area when the portion and the another portion of the polishing belt, respectively, are within the processing area. 46. A method of creating a bi-directional linear movement of a portion of a polishing pad disposed within a processing area used for chemical mechanical polishing of a workpiece comprising the steps of: creating rotational movement of a drive shaft; translating the rotational movement on the drive shaft to a bi-directional linear movement of a slide member; and causing the bi-directional linear movement of the portion of the polishing pad within the processing area with the bi-directional linear movement of the slide member corresponds, the bi-directional linear movement of the portion of the polishing pad being used when chemically mechanically polishing the workpiece.

47. A method according to above wherein during the step of causing the polishing pad is disposed between a supply spool and a receive spool.

48. A method according to above wherein during the step of causing the polishing pad passes through rollers disposed on the slide member.

49. A method according to above wherein the step of translating provides horizontal bidirectional linear movement of the slide member, and the step of causing provides horizontal bi- directional linear movement of the portion of the polishing pad within the processing area.

50. A method according to above wherein the portion of the polishing pad moves horizontally at least two times as far as the slide member moves horizontally.

51. A method according to above wherein the portion of the polishing pad moves a greater amount than the slide member. 52. A method according to above wherein the step of causing includes providing a pad path on a plurality of rollers.

53. A method according to above wherein the pad path provides that only a back surface of the polishing pad will physically contact the plurality of rollers.

54. A method according to above wherein during the step of causing the polishing pad passes through rollers disposed on the slide member.

55. A method according to above wherein the step of translating provides horizontal bidirectional linear movement of the slide member, and the step of causing provides horizontal bidirectional linear movement of the portion of the polishing pad within the processing area.

56. A method according to above wherein the portion of the polishing pad moves horizontally at least two times as far as the slide member moves horizontally. 57. A method according to above wherein the portion of the polishing pad moves a greater amount than the slide member.

58. A method according to above wherein the step of causing includes providing a pad path on a plurality of rollers. 59. A method according to above wherein the pad path provides that only a back surface of the polishing pad will physically contact the plurality of rollers.

60. An apparatus for creating bi-directional linear motion within a predetermined area with a portion of a polishing pad corresponding to a processing area used for chemical mechanical polishing of a workpiece using a solution comprising: a drive assembly that contains a rotatable shaft; a slide member that is moveable within a slide area, the slide member being mechanically coupled to the drive assembly, such that rotation of the rotatable shaft creates bilinear movement of the slide member; and wherein the polishing pad is disposed through the slide member, such that bi-linear movement of the slide member creates a corresponding bilinear movement of the portion of the polishing pad, the bi-linear movement of the portion of the polishing pad being used when chemically mechanically polishing the workpiece.

61. An apparatus according to above wherein the drive assembly includes: a gear box coupled to the rotatable shaft and which contains another rotatable shaft; a crank coupled to the another rotatable shaft; and a link coupled between the link and the slide member.

62. An apparatus according to above wherein the slide member includes a plurality of rollers.

63. An apparatus according to above wherein the bi-linear movement of the slide member is horizontal.

64. An apparatus according to above wherein the bi-linear movement of the portion of the polishing pad in the processing area is horizontal. 65. An apparatus according to above further including a plurality of rollers that provides a pad path between a supply spool and a receive spool.

66. An apparatus according to above wherein the plurality of rollers are arranged such that the pad path provides that only a back surface of the polishing pad will physically contact the plurality of rollers. 67. A drive assembly for providing a path for horizontal linear movement of a portion of a polishing pad within a processing area, the polishing pad being disposed between a supply spool and a receive spool, the drive assembly comprising: a driving device that contains a rotatable shaft; a single casting of metal, the casting containing openings, the casting further including a horizontal slide area; a supply pin, a receive pin, and a plurality of rollers disposed within the openings on the casting, the supply pin and the receive pin capable of having the supply spool and the receive spool respectively attached thereto with the polishing pad being disposed therebetween; and a horizontal slide member that is horizontally moveable within the horizontal slide area, the horizontal slide member being mechanically coupled to the driving device and capable of being coupled to the polishing pad, such that rotation of the rotatable shaft creates horizontal movement of the slide member and will create the horizontal linear movement of the polishing pad.

68. An apparatus according to above wherein the horizontal slide member moved in a bilinear movement direction and is capable of causing horizontal bi-linear movement of the portion of the polishing pad.

69. An apparatus according to above wherein the driving device includes: a gear box coupled to the rotatable shaft and which contains another rotatable shaft; a crank coupled to the another rotatable shaft; and a link coupled between the link and the horizontal slide member.

70. An apparatus according to above further including a plurality of rails attached to the casting on which the horizontal slide member is horizontally moveable.

71. A method of tensioning a portion of a polishing pad within a processing area comprising the step of: providing a polishing pad having a portion disposed within a processing area, one end attached to a supply spool, and another end attached to a receive spool, locking one of the supply spool and the receive spool, such that movement of the corresponding end of the polishing pad will not occur; and tensioning the corresponding other end of the polishing pad from the other of the supply spool and the receive spool using a tensioning mechanism so that bi- linear movement of the portion of the polishing pad within the processing area using another drive mechanism occurs while the polishing pad is tensioned by the tensioning mechanism.

72. A method according to above wherein: the step of locking locks the supply spool; the step of tensioning tensions from the receive spool; and further including the step of incrementally moving the polishing pad so that another portion is disposed within the processing area, the step of incrementally moving using the tensioning mechanism to incrementally move the polishing pad. 73. A method according to above wherein the step of incrementally moving includes the steps of: eliminating tension from the receive spool; unlocking the supply spool; and incrementally moving the polishing pad using the tensioning mechanism while the supply spool is unlocked. 74. A method according to above wherein the step of tensioning includes the steps of: continuously monitoring the tension applied to the polishing pad; and continuously adjusting the tension based upon the continuously monitored tension.

75. A method according to above wherein the step of continuously monitoring the tension monitors a current supplied to a motor that is used in the step of tensioning. 76. A method according to above wherein the step of tensioning uses the motor to tension to the receive spool and to incrementally move the polishing pad.

77. A method according to above wherein the step of providing further provides a plurality of rollers disposed on a slide member and another plurality of rollers.

78. A method according to above wherein the step of providing provides a pad path in which only a back surface of the polishing pad will physically contact the plurality of rollers and the another plurality of rollers.

79. A method according to above wherein the step of tensioning uses the motor to tension to the receive spool and to incrementally move the polishing pad.

80. A method according to above wherein the step of tensioning tensions an entire portion of the polishing pad disposed between the supply spool and the receive spool.

81. A method according to above wherein the pad path passes over the plurality of rollers and the another plurality of rollers.

82. A method according to above wherein the step of tensioning includes the steps of: continuously monitoring the tension applied to the polishing pad; and continuously adjusting the tension based upon the continuously monitored tension.

83. A method according to above wherein the step of continuously monitoring the tension monitors a current supplied to a motor that is used in the step of tensioning.

84. A method according to above wherein the step of tensioning uses the motor to tension to the receive spool and to incrementally move the polishing pad. 85. An apparatus for tensioning and incrementing a portion of a polishing pad within a processing area used for chemical mechanical polishing of a workpiece using a solution comprising: a drive assembly that contains a rotatable shaft; a slide member that is moveable within a slide area, the slide member being mechanically coupled to the drive assembly, such that rotation of the rotatable shaft creates bi-linear movement of the slide member, wherein the polishing pad is disposed through the slide member, such that bi-linear movement of the slide member creates a corresponding bi-linear movement of the portion of the polishing pad; and a supply spool; a receive spool; a plurality of rollers that create a pad path between the supply spool and the receive spool; and a tensioning mechanism that provides tension to the receive spool, and thereby the portion of the polishing pad, when the portion of the polishing pad is being used to chemically mechanically polishing the workpiece. 86. An apparatus according to above wherein the tensioning mechanism is coupled to the receive spool.

87. An apparatus according to above further including a locking mechanism coupled to the supply spool.

88. An apparatus according to above further including a controller that controls the tension provided by the tensioning mechanism.

89. An apparatus according to above wherein the controller receives a feedback signal that assists in controlling the tension provided by the tensioning mechanism.

90. An apparatus according to above wherein the tensioning mechanism further provides for incrementing the polishing pad. 91. An apparatus according to above wherein the tensioning mechanism will increment the polishing pad when the locking mechanism unlocks the supply spool.

Claims

1. A method of providing bi-directional linear polishing comprising the steps of: providing a polishing belt on a support mechanism between a supply area and a receive area, the polishing belt having a first end and a second end and a polishing side and a backside, such that the first end initially comes off the supply area and is connected to the receive area and the second end remains connected to the supply area; polishing by bi-directionally linearly moving a portion of the polishing belt within a polishing area; advancing the polishing belt to obtain another portion that will be used for polishing, wherein the step of advancing advances the polishing belt over the support mechanism such that the polishing side of the polishing belt is not degraded by the support mechanism; polishing by bi-directionally linearly moving the another portion of the polishing belt; and repeating the steps of advancing and polishing using another portion.

2. A method according to claim 1 wherein the step of advancing advances the polishing belt over a plurality of rollers within the support mechanism that support the polishing belt from the backside of the polishing belt and not the polishing side of the polishing belt.

3. The method according to claim 2 further including the steps of: introducing a first workpiece to the polishing area prior to polishing using the portion of the polishing belt; removing the first workpiece when polishing of the first workpiece is completed; and introducing a second workpiece to the polishing area prior to polishing using the another portion of the polishing belt.

4. The method according to claim 3 wherein during the step of polishing, there is also included the step of tensioning the portion of the polishing belt within the polishing area.

5. The method according to claim 4, wherein the step of tensioning uses the plurality of rollers disposed between the supply area and the receive area.

6. The method according to claim 2 wherein the step of advancing gradually advances to the another portion such that there is an overlap between the portion and the another portion.

7. The method according to claim 1 wherein during the step of advancing a previously used portion is received into the receive area and a new portion comes off the supply area.

8. The method according to claim 2 wherein, during the steps of polishing, there is simultaneously occurring a step of providing a force to the backside of the polishing belt within the polishing area.

9. The method according to claim 9 wherein the step of providing the force applies air.

10. The method according to claim 1 wherein the step of advancing gradually advances to the another portion such that there is an overlap between the portion and the another portion.

11. The method according to claim 1 wherein during the step of advancing a previously used portion is received into the receive area and a new portion comes off the supply area.

12. The method according to claim 1 wherein: the step of polishing by bi-directionally moving the portion of the polishing belt within the polishing area moves the portion of the polishing belt over the support mechanism so that only the backside of the polishing belt contacts the support mechanism; and the step of polishing by bi-directionally moving the another portion of the polishing belt within the polishing area moves the another portion of the polishing belt over the support mechanism so that only the backside of the polishing belt contacts the support mechanism.

13. The method according to claim 12 wherein the steps of providing and advancing the polishing belt each cause the first end and the second end of the polishing belt to be positioned so that the portion and the another portion, respectively, can be moved during the steps of polishing.

14. The method according to claim 13, wherein, during the steps of polishing, the ends of the polishing belt not being used for polishing remain rolled within the supply area and the receive area, respectively, so that the polishing side of the polishing belt rolled within the supply area and the receive area is not degraded during the steps of polishing.

15. The method according to claim 14 wherein: during the step of polishing by bi-directionally moving the portion of the polishing belt within the polishing area, the portion of the polishing belt is moved using a plurality of moving and rotatable rollers of the support mechanism that only contact the backside of the portion of the polishing belt; and during the step of polishing by bi-directionally moving the another portion of the polishing belt within the polishing area, the another portion of the polishing belt is moved using the plurality of moving and rotatable rollers of the support mechanism that only contact the backside of the another portion of the polishing belt.

16. The method according to claim 15 wherein, during the steps of polishing, there is also included the step of tensioning the portion and the another portion, respectively, of the polishing belt within the polishing area.

17. The method according to claim 13 wherein, during the steps of polishing, the first end and the second end of the polishing belt remain stationary within the supply area and the receive area, respectively.

18. The method according to claim 17 wherein during the step of polishing, there is also included the step of tensioning the portion of the polishing belt within the polishing area.

19. The method according to claim 18 wherein the steps of polishing each further include the step of levitating a certain portion of the polishing belt within the polishing area over a platen to cause contact, and thereby the polishing, between the frontside of the polishing belt and a frontside of a workpiece being polished.

20. The method according to claim 12 wherein the steps of polishing each further include the step of levitating a certain portion of the polishing belt within the polishing area over a platen to cause contact, and thereby the polishing, between the frontside of the polishing belt and a frontside of a workpiece being polished.

21. The method according to claim 20 wherein: during the step of polishing by bi-directionally moving the portion of the polishing belt within the polishing area, the portion of the polishing belt is moved using a plurality of moving and rotatable rollers of the support mechanism that only contact the backside of the portion of the polishing belt; and during the step of polishing by bi-directionally moving the another portion of the polishing belt within the polishing area, the another portion of the polishing belt is moved using the plurality of moving and rotatable rollers of the support mechanism that only contact the backside of the another portion of the polishing belt.

22. A polishing apparatus adapted to polish using a polishing belt having a first end and a second end and a polishing side and a backside, comprising: a receive area to which the first end of the polishing belt can be connected; a supply area to which the second end of the polishing belt can be connected; a support structure that provides a path for the polishing belt to travel between the receive area and the supply area, such that a workpiece processing area exists along the path, the support structure being constructed such that the polishing side of the polishing belt is not used by the support structure to support the polishing belt; a first drive mechanism that is capable of bi-directionally linearly polishing by bi- directionally linearly moving a portion of the polishing belt within the processing area; and a second drive mechanism that provides for advancing the polishing belt, such that another portion of the polishing belt can be located within the processing area and used for bidirectional linearly polishing by bi-directionally linearly moving the another portion of the polishing belt within the processing area.

23. The apparatus according to claim 22 further including a tensioning mechanism to tension the portion of the polishing belt within the polishing area.

24. The apparatus according to claim 22 wherein the support structure includes a plurality of rollers disposed on a polishing belt path that exists between the supply area and the receive area and wherein the polishing belt advances of the plurality of rollers so that only the backside of the polishing belt and not the polishing side of the polishing belt contacts the plurality of rollers.

25. The apparatus according to claim 22 wherein the support structure supports the portion of the polishing belt so that the polishing side of the polishing belt is not used by the support structure to support the portion of the polishing belt while the portion of the polishing belt is being used to bi-directionally linearly polish within the processing area.

26. The apparatus according to claim 25 wherein the receive area is adapted to position the first end of the polishing belt and the supply area is adapted to position the second end of the polishing belt so that so that the portion and the another portion, respectively, can be bi- directionally linearly moved by the first drive mechanism to bi-directionally linearly polish within the processing area.

27. The apparatus according to claim 26 wherein the second drive mechanism further provides for tensioning of the portion and the another portion of the polishing belt within the processing area when the portion and the another portion, respectively, are within the processing area.

28. The apparatus according to claim 22 wherein the second drive mechanism further provides for tensioning of the portion and the another portion of the polishing belt within the processing area when the portion and the another portion of the polishing belt, respectively, are within the processing area.

29. A method of creating a bi-directional linear movement of a portion of a polishing pad disposed within a processing area used for chemical mechanical polishing of a workpiece comprising the steps of: creating rotational movement of a drive shaft; translating the rotational movement on the drive shaft to a bi-directional linear movement of a slide member; and causing the bi-directional linear movement of the portion of the polishing pad within the processing area with the bi-directional linear movement of the slide member corresponds, the bidirectional linear movement of the portion of the polishing pad being used when chemically mechanically polishing the workpiece.

30. The method according to claim 29 wherein during the step of causing the polishing pad passes through rollers disposed on the slide member.

31. The method according to claim 30 wherein the step of translating provides horizontal bidirectional linear movement of the slide member, and the step of causing provides horizontal bidirectional linear movement of the portion of the polishing pad within the processing area.

32. The method according to claim 30 wherein the portion of the polishing pad moves a greater amount than the slide member.

33. The method according to claim 32 wherein the pad path provides that only a back surface of the polishing pad will physically contact the plurality of rollers.

34. The method according to claim 29 wherein the step of translating provides horizontal bidirectional linear movement of the slide member, and the step of causing provides horizontal bidirectional linear movement of the portion of the polishing pad within the processing area.

35. The method according to claim 29 wherein the portion of the polishing pad moves a greater amount than the slide member.

36. The method according to claim 29 wherein the pad path provides that only a back surface of the polishing pad will physically contact a plurality of rollers on a pad in the step of causing.

37. An apparatus for creating bi-directional linear motion within a predetermined area with a portion of a polishing pad corresponding to a processing area used for chemical mechanical polishing of a workpiece using a solution comprising: a drive assembly that contains a rotatable shaft; a slide member that is moveable within a slide area, the slide member being mechanically coupled to the drive assembly, such that rotation of the rotatable shaft creates bi-linear movement of the slide member; and wherein the polishing pad is disposed through the slide member, such that bi-linear movement of the slide member creates a corresponding bi-linear movement of the portion of the polishing pad, the bi-linear movement of the portion of the polishing pad being used when chemically mechanically polishing the workpiece.

38. The apparatus according to claim 37 wherein the drive assembly includes: a gear box coupled to the rotatable shaft and which contains another rotatable shaft; a crank coupled to the another rotatable shaft; and a link coupled between the link and the slide member.

39. The apparatus according to claim 38 wherein the slide member includes a plurality of rollers.

40. The apparatus according to claim 39 wherein the bi-linear movement of the slide member is horizontal.

41. The apparatus according to claim 40 further including a plurality of rollers that provides a pad path between a supply spool and a receive spool.

42. The apparatus according to claim 41 wherein the plurality of rollers are arranged such that the pad path provides that only a back surface of the polishing pad will physically contact the plurality of rollers.

43. A method of tensioning a portion of a polishing pad within a processing area comprising the step of: providing a polishing pad having a portion disposed within a processing area, one end attached to a supply spool, and another end attached to a receive spool. locking one of the supply spool and the receive spool, such that movement of the corresponding end of the polishing pad will not occur; and tensioning the corresponding other end of the polishing pad from the other of the supply spool and the receive spool using a tensioning mechanism so that bi-linear movement of the portion of the polishing pad within the processing area using another drive mechanism occurs while the polishing pad is tensioned by the tensioning mechanism.

44. The method according to claim 43 wherein: the step of locking locks the supply spool; the step of tensioning tensions from the receive spool; and further including the step of incrementally moving the polishing pad so that another portion is disposed within the processing area, the step of incrementally moving using the tensioning mechanism to incrementally move the polishing pad.

45. The method according to claim 44 wherein the step of incrementally moving includes the steps of: eliminating tension from the receive spool; unlocking the supply spool; and incrementally moving the polishing pad using the tensioning mechanism while the supply spool is unlocked.

46. The method according to claim 43 wherein the step of tensioning includes the steps of: continuously monitoring the tension applied to the polishing pad; and continuously adjusting the tension based upon the continuously monitored tension.

47. The method according to claim 46 wherein the step of tensioning uses the motor to tension to the receive spool and to incrementally move the polishing pad.

48. The method according to claim 47 wherein the step of providing further provides a plurality of rollers disposed on a slide member and another plurality of rollers.

49. The method according to claim 43 wherein the pad path passes over the plurality of rollers and the another plurality of rollers.

50. An apparatus for tensioning and incrementing a portion of a polishing pad within a processing area used for chemical mechanical polishing of a workpiece using a solution comprising: a drive assembly that contains a rotatable shaft; a slide member that is moveable within a slide area, the slide member being mechanically coupled to the drive assembly, such that rotation of the rotatable shaft creates bi-linear movement of the slide member, wherein the polishing pad is disposed through the slide member, such that bi-linear movement of the slide member creates a corresponding bi-linear movement of the portion of the polishing pad; and a supply spool; a receive spool; a plurality of rollers that create a pad path between the supply spool and the receive spool; and a tensioning mechanism that provides tension to the receive spool, and thereby the portion of the polishing pad, when the portion of the polishing pad is being used to chemically mechanically polishing the workpiece.

51. The apparatus according to claim 50 wherein the tensioning mechanism is coupled to the receive spool.

52. The apparatus according to claim 51 further including a locking mechamsm coupled to the supply spool.

53. The apparatus according to claim 52 further including a controller that controls the tension provided by the tensioning mechanism.

54. The apparatus according to claim 52 wherein the controller receives a feedback signal that assists in controlling the tension provided by the tensioning mechanism.

55. The apparatus according to claim 52 wherein the tensioning mechanism further provides for incrementing the polishing pad.

56. The apparatus according to claim 55 wherein the tensioning mechanism will increment the polishing pad when the locking mechanism unlocks the supply spool.