JP2014099598A - Damper for polishing pad conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pad conditioner device which remarkably suppresses vibrations or eliminates vibrations.SOLUTION: A conditioner device 160 used for polishing a substrate includes: a conditioner head 166 which is built so as to receive an end effector 170 for adjusting a surface of a polishing pad; an arm 164 which supports the conditioner head; a base 162 which supports the arm; and a damper system 190 which is fixed to the base. The base includes an actuator 180 which is connected with the arm for moving the arm and the conditioner head in a lateral direction above the polishing pad. The damper system is formed so as to suppress vibrations of the arm.

Description

  The present disclosure relates to polishing pad conditioning.

  Integrated circuits are typically formed on a substrate by sequentially depositing a conductive layer, a semiconductor layer, or an insulating layer on a silicon wafer. Various manufacturing processes require planarization of layers on the substrate. For example, when polishing a metal layer to form vias, plugs, and lines in a trench of the patterned layer, such as a particular application, the top layer is polished until the top surface of the patterned layer is exposed. The When planarizing a dielectric layer for other applications, such as photolithography, the upper layer is polished until the desired thickness remains above the lower layer.

  Chemical mechanical polishing (CMP) is one accepted planarization method. This planarization method typically requires that the substrate be mounted on a carrier or polishing head. The exposed surface of the substrate is typically placed in contact with the rotating polishing pad. The carrier head places a controllable load on the substrate and presses the substrate against the polishing pad. The abrasive polishing slurry is usually supplied to the surface of the polishing pad.

  After a CMP process is performed over a period of time, the surface of the polishing pad wears out and becomes smooth due to accumulation of slurry by-products and / or material removed from the substrate and / or polishing pad . When worn down and smoothed, the pad roughness is reduced and the applied local pressure is reduced, thereby reducing the polishing rate. Furthermore, when worn down and smoothed, the polishing pad may lose some of its ability to hold slurry, further reducing the polishing rate.

  In general, the characteristics of a polishing pad that has been worn away and smoothed can be restored by an adjustment process using a pad conditioner. The pad conditioner is used to remove unwanted deposits on the polishing pad and regenerate the surface of the polishing pad to the desired roughness. A normal pad conditioner includes an abrasive head that is entirely embedded with diamond abrasive grains, and the pad surface of the polishing pad that has been worn down and smoothed is rubbed against the abrasive grain head to regenerate the surface structure of the pad. be able to.

  In some adjustment systems that use several polishing schemes, the pad conditioner, particularly the pad conditioner arm, exhibits significant vibrations. The vibration is harmful to the arm and can reduce the effectiveness of the adjustment process. Moreover, this vibration can be heard in many cases and can actually make an unacceptably loud sound. However, by placing a tuned mass damper at the bottom of the conditioner, the vibration can be significantly reduced or eliminated.

  In one aspect, a conditioner apparatus for use in polishing a substrate includes a conditioner head configured to receive an end effector for adjusting a surface of the polishing pad, an arm that supports the conditioner head, and an arm. A supporting base and a damper system fixed to the base are included. The base is connected to the arm and includes an actuator that moves the arm and the conditioner head laterally over the polishing pad. The damper system is configured to reduce arm vibration.

  Embodiments can include one or more of the following features. The actuator can be a rotary actuator configured to sweep the arm over the polishing pad. The damper system is fixed to the rotary actuator and can rotate with the rotary actuator. The damper system can include a damper mass. The damper mass can be attached to the base by at least one damper. The at least one damper may be a damping material layer. The damper mass can be attached to the base by a plurality of dampers. The plurality of dampers can include a dashpot. The plurality of dampers can be arranged so as to define a main axis parallel to the axis of the main vibration mode of the arm. The plurality of dampers can be arranged to define a main axis parallel to the longitudinal axis of the arm. The conditioner head may include a vertical actuator connected to the end effector and controlling the vertical position of the end effector. In another aspect, a non-transitory computer program product tangibly embodied in a machine-readable storage device includes instructions for performing the method.

  Multiple implementations may optionally include one or more of the following advantages. The vibration of the pad conditioner, particularly the pad conditioner arm can be reduced. The effectiveness of the adjustment process can be improved. Noise generated by the pad conditioner can be reduced.

  The details of one or more implementations are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.

It is a schematic sectional side view of an example of a grinding | polishing apparatus. It is a top view of the polish station of polish device. It is sectional drawing of a conditioner apparatus. It is a top view of the base of an adjustment apparatus.

  Like reference numbers and designations in the various embodiments indicate like elements.

  FIG. 1 shows an example of a polishing apparatus 100. The polishing apparatus 100 includes a rotatable disk-shaped platen 120, and a polishing pad 110 is positioned on the platen. The platen 120 is operable to rotate about the axis 125. For example, the motor 122 can rotate the drive shaft 124 to rotate the platen 120. The platen 120 can rotate at about 30-200 rpm.

  The polishing pad 110 can have a polishing surface 116. The polishing pad 110 can be a two-layer polishing pad having an outer polishing layer 112 and a softer backing layer 114. The layer that provides the polishing surface 116, eg, the outer polishing layer 112, can be a porous polyurethane, eg, IC-1000 material.

  The polishing apparatus 100 can include a port 130 that dispenses a polishing liquid 132, such as slurry, onto the polishing pad 110 to the pad. The slurry 132 can include silica abrasive particles, for example, the slurry can be SS-12.

  The polishing apparatus 100 includes at least one carrier head 140. Although only one carrier head 140 is shown, more carrier heads can be provided to hold additional substrates so that the surface area of the polishing pad 110 can be used efficiently.

  The carrier head 140 is operable to hold the substrate 10 in contact with the polishing pad 110. The carrier head 140 can independently control polishing parameters associated with each substrate, such as pressure. The carrier head 140 can include a retaining ring 142 that retains the substrate 10 under the flexible membrane 144. The pressure applied to the substrate 10 is controlled by pressurizing one or more chambers behind the membrane 144. For ease of illustration, only three chambers are shown in FIG. 1, but there can be one or two chambers, four or more chambers, eg, five chambers.

  The carrier head 140 is suspended from a support structure 150, such as a carousel or track, and is connected to the carrier head rotation motor 154 by a drive shaft 152 so that the carrier head can rotate about an axis 155. The carrier head 140 can rotate at about 30-200 rpm. Optionally, the carrier head 140 can vibrate laterally, for example, on a slider on the carousel 150 or track, or by rotational vibration of the carousel itself. In operation, the platen rotates about its central axis 125 and the carrier head rotates about its central axis 155 and translates laterally across the top surface of the polishing pad.

  The polishing apparatus can also include a polishing pad conditioner 160 that scrapes the polishing pad 110 to maintain the polishing pad 110 in a consistent polishing state. The polishing pad conditioner 160 includes a base 162, an arm 164 capable of laterally sweeping over the polishing pad 110, and a conditioner head 166 connected to the base 162 by the arm 164. The base 162 is attached to the frame 102 of the polishing apparatus 100 and the frame 102 can also support other components, such as the platen 120 and the support structure 150. Conditioner head 166 includes a polishing surface configured to condition surface 116 of polishing pad 110. The polishing surface can be rotatable and the pressure of the polishing surface against the polishing pad can be controllable.

  Referring to FIG. 2, in one mode of operation, the polishing pad 110 is adjusted by the conditioner head 166 while the polishing pad 110 is polishing the substrate 10 attached to the carrier head 140. In some embodiments, the arm 164 is pivotally attached to the base 162 and sweeps left and right to move the conditioner head 166 in an oscillating sweep movement (indicated by arrow S) across the polishing pad 110. The motion of the conditioner head 166 can be synchronized with the motion of the carrier head 140 to prevent a collision.

  Optionally, the polishing apparatus 100 can include a cleaning cup 168 that is supported on the frame 102 and positioned where the arm 164 can position the conditioner head 166 within the cup 168. Is done. The cleaning cup 168 can include a fluid for cleaning the conditioner head 166, or a set of nozzles can be attached to the cup to spray the cleaning liquid onto the conditioner head 166. Before and after the adjustment operation, the conditioner head 166 can be positioned in the cleaning cup 168 for cleaning.

  Referring to FIG. 3, the conditioner head 166 includes an end effector 170 that is rotatable and vertically movable, and the end effector 170 holds the adjustment disk 172. The adjustment disk 172 has a bottom surface in which diamond abrasive grains are embedded, and the surface structure of the pad can be regenerated by rubbing the bottom surface against the surface of the polishing pad. The adjustment disk 172 can be held in the end effector by a magnet or by mechanical fasteners. A gimbal mechanism can be coupled between the end effector 170 and the conditioner head 166, which allows the end effector 170 to tilt at an angle with respect to the arm 164.

  Control of the vertical movement of the end effector 170 and the pressure of the adjustment disk 172 can be provided by a vertical actuator in the conditioner head 166, eg, a pressurizable chamber 174 positioned to apply downward pressure to the end effector 170. . Alternatively, the vertical motion and pressure control may be achieved by a vertical actuator in the base 162 that lifts the arm 164 and the conditioner head 166 as a whole, or the angle of inclination of the arm 164 and hence the conditioner above the polishing pad 110. It can be provided by a pivot connection between the arm 164 and the base 162 that allows the height of the head 166 to be controlled.

  The rotation of the end effector 170 can be provided by a motor in the base 162 that is connected by a belt drive that extends through the arm 164 and engages a drive shaft 174 that is connected to the end effector 170. To do. A description of the conditioner head can be found in US Pat. No. 6,036,583, which is incorporated herein by reference.

  A controller 190 (see FIG. 1), for example, connects a computer to the adjustment device 160 to control the lateral sweep of the arm 164, the rotational speed of the end effector 170, and the downward force of the end effector 170 on the polishing pad. can do.

  The base 162 includes a rotary actuator 180 held on a support 182 fixed to the frame. The arm 164 is fixed to the rotary actuator 180, and the arm 162 is swept laterally across the polishing pad as the actuator 180 rotates.

  A damper system 190 is attached to the base 162 of the conditioner device 160. For example, the damper system 190 can be attached to the rotary actuator 180. In this case, the damper system 190 can rotate with the actuator 180.

  The damper system 190 includes a damper mass 192. The damper mass 192 is a heavy object formed from, for example, metal. The mass of the damper 192 is selected to increase the arm stabilization threshold. A cover 184 extends over the damper mass 192 to protect the damper mass 192 from slurry and other dirt, for example, to prevent corrosion.

  The damper mass 192 can be secured using a rigid connection to the base 162 by, for example, mechanical fasteners, or one or more dampers 194 are positioned between the damper mass 192 and the base 162. can do.

  Each damper 194 can be a dashpot, such as a hydraulic or mechanical damper, or simply a viscoelastic material layer.

  Usually, the main vibration mode is parallel to the longitudinal axis of the arm 164. Accordingly, the damper 194 can be positioned to preferentially reduce vibration in this mode. As shown in FIG. 4, the damper 194 is positioned so that the major axis A of the shape defined by the damper 194 (shown in perspective) is parallel to the longitudinal axis of the arm 164 and is in the same vertical plane. be able to.

  In general, if the damper mass 190 is fixed without damping or with minimal damping, the natural frequency of the arm 164 can be changed so that the vibration of the conditioner arm 164 is significantly reduced. it can. For example, the conditioner device 160 can operate with an acceptable degree of vibration even if the consumable set is different and the range of forces acting downward is different. In general, if the damper mass 190 is connected to the base 162 by sufficient damper 192, the problem vibration can be significantly reduced or substantially eliminated. Thus, the use of damper system 190 greatly expands the range of applications in which the arm can be used without causing any problem vibration.

  Although the above description focuses on the conditioner head, the damper system can also be applied to other cantilever components in the polishing system that are susceptible to vibration. For example, the damper system can be applied to an arm that holds a polishing head.

  The above polishing apparatus and method can be applied in various polishing systems. Either the polishing pad, the carrier head, or both can be moved to provide relative motion between the polishing surface and the substrate. For example, the platen can circulate rather than rotate. The polishing pad can have a shape other than circular. Some aspects of the endpoint detection system may be applicable to linear polishing systems, such as systems where the polishing pad is a linear or reel-to-reel belt that moves linearly. The abrasive layer can be a standard (eg, polyurethane with or without filler) abrasive material, soft material, or fixed abrasive material. The arm can undergo a linear extension motion rather than an angular sweep.

  As used herein, the term “substrate” can include, for example, a product substrate (eg, a substrate including multiple memories or processor dies), a test substrate, a bare substrate, and a gating substrate. The substrate can be at various stages of integrated circuit fabrication, for example, the substrate can be a bare wafer, or the substrate can include one or more deposited and / or patterned layers. it can. The term “substrate” can include circular disks and rectangular sheets.

  Embodiments of the invention and all functional operations described herein include computer software, firmware, or structural means disclosed herein and structural equivalents thereof in digital electronic circuitry or , In hardware, or a combination thereof. Embodiments of the present invention are implemented as one or more computer program products, i.e., for execution by a data processing device, e.g., a programmable processor, a computer or multiple processors or computers, or control the operation of a data processing device. Therefore, it can be implemented as one or more computer programs tangibly embodied in a non-transitory machine-readable storage medium.

  Specific embodiments of the invention have been described. Other embodiments are within the scope of the appended claims.

DESCRIPTION OF SYMBOLS 10 Substrate 100 Polishing apparatus 102 Frame 110 Polishing pad 112 Outer polishing layer 114 Backing layer 116 Polishing surface 120 Platen 122 Motor 124 Drive shaft 125 Shaft 130 Port 132 Polishing liquid 132 Slurry 140 Carrier head 144 Flexible film 150 Support structure 150 Carousel 152 Drive shaft 154 Carrier head rotation motor 155 axis 160 conditioner 162 base 164 arm 166 conditioner head 168 cleaning cup 170 end effector 172 adjustment disk 174 pressurizable chamber 174 drive shaft 180 rotary actuator 182 support 184 cover 190 damper system 192 Damper mass 194 Damper

Claims (11)

A conditioner device used for polishing a substrate,
A conditioner head constructed to receive an end effector for adjusting the surface of the polishing pad;
An arm that supports the conditioner head;
A base that supports the arm, the base including an actuator connected to the arm to move the arm and the conditioner head laterally over the polishing pad;
A damper system secured to the base, the damper system comprising: a damper system configured to reduce vibration of the arm.   The apparatus of claim 1, wherein the actuator comprises a rotary actuator configured to sweep the arm over the polishing pad.   The apparatus of claim 2, wherein the damper system is fixed to the rotary actuator and rotates with the rotary actuator.   The apparatus of claim 1, wherein the damper system includes a damper mass.   The apparatus of claim 4, wherein the damper mass is attached to the base by at least one damper.   The apparatus of claim 5, wherein the at least one damper includes a damping material layer.   The apparatus of claim 6, wherein the damper mass is attached to the base by a plurality of dampers.   The apparatus of claim 7, wherein the plurality of dampers includes a dashpot.   The apparatus of claim 7, wherein the plurality of dampers are arranged to define a main axis parallel to an axis of a main vibration mode of the arm.   The apparatus of claim 7, wherein the plurality of dampers are arranged to define a main axis parallel to a longitudinal axis of the arm.   The apparatus of claim 1, comprising a vertical actuator in the conditioner head, connected to the end effector and controlling a vertical position of the end effector.

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