Patent Publication Number: US-11648644-B2

Title: Polishing pad conditioning apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0000251 filed on Jan. 2, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Apparatuses consistent with example embodiments relate to a polishing pad conditioning apparatus. 
     2. Description of the Related Art 
     In the manufacturing process of a semiconductor device, a chemical mechanical polishing (CMP) process using a CMP device may be used for planarizing (or level out) a wafer. A CMP device of the related art includes a polishing pad for polishing a surface of a wafer and a polishing pad conditioning apparatus including a diamond disk for conditioning a polishing surface of the polishing pad. However, in such a device, there may be the issue of foreign materials entering an outer housing of the device and advancing towards a rotary motor which drives the diamond disk to rotate for conditioning the polishing surface of the polishing pad. Also, the part of the device on which the diamond disk is installed may experience uneven pressure and break. 
     SUMMARY 
     One or more example embodiments may provide a polishing pad conditioning apparatus capable of preventing foreign materials from entering a housing of the apparatus and moving towards a rotary motor rotating a conditioning disk. 
     One or more example embodiments may also provide a polishing pad conditioning apparatus capable of reducing uneven wear of a conditioning disk and capable of reducing damage to a structure having the conditioning disk installed thereon. 
     According to an aspect of an example embodiment, there is provided a polishing pad conditioning apparatus including an apparatus body, a pivot arm provided on the apparatus body and including a housing having an internal space and provided at a distal end portion of the pivot arm and a head unit disposed at the distal end portion of the pivot arm. The head unit includes: a rotary motor provided in the internal space of the housing, the rotary motor including a rotary shaft; a foreign material blocking member connected to the rotary shaft; a disk holder connected to the rotary shaft; and a conditioning disk coupled to the disk holder. The foreign material blocking member includes a fluid flow groove configured to guide a movement of fluid for preventing foreign objects from entering the housing on an outer surface of the foreign material blocking member. 
     According to an aspect of another example embodiment, there is provided a polishing pad conditioning apparatus including an apparatus body, a pivot arm extending from the apparatus body and including a housing having an internal space and provided at a first end portion of the pivot arm, and a head unit disposed at the first end portion of the pivot arm. The head unit includes: a rotary motor provided in the internal space of the housing and comprising a rotary shaft, a deformation member connected to the rotary shaft of the rotary motor, a disk holder connected at a first portion of the deformation member along an axial direction of the deformation member, and a conditioning disk coupled to the disk holder. The deformation member includes a deformation groove for reducing deformation stress induced by an external force to the conditioning disk. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and/or other aspects, features, and advantages of the disclosure will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    illustrates a chemical mechanical polishing apparatus including a polishing pad conditioning apparatus according to an example embodiment; 
         FIG.  2    illustrates a polishing pad conditioning apparatus according to an example embodiment; 
         FIG.  3    illustrates an exploded perspective view of a head unit of a polishing pad conditioning apparatus including a fluid flow groove according to an example embodiment; 
         FIG.  4    illustrates a cross-sectional view taken along line X-X′ of  FIG.  2   ; 
         FIG.  5    illustrates an enlarged view of an example embodiments of a fluid flow groove; 
         FIG.  6    illustrates an enlarged view of another example embodiment of a fluid flow groove; 
         FIG.  7    illustrates an enlarged view of yet another example embodiment of a fluid flow groove; 
         FIG.  8    illustrates an enlarged view of yet another example embodiment of a fluid flow groove; and 
         FIG.  9    illustrates an enlarged view of yet another example embodiment of a fluid flow groove. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, example embodiments of the present inventive concept will be described with reference to the accompanying drawings. 
       FIG.  1    illustrates a chemical mechanical polishing apparatus  10  including a polishing pad conditioning apparatus  100  according to an example embodiment. 
     Referring to  FIG.  1   , a chemical mechanical polishing apparatus  10  may include, for example, a turntable  20 , a wafer carrier  40 , a slurry dispensing unit  50 , and a polishing pad conditioning device  100 . 
     The turntable  20  may be rotatably installed on a rotary shaft (not illustrated), and a top portion of the turntable  20  may have the shape of a circular flat plate. The turntable  20  may be rotated in a predetermined direction, for example, in a counter-clockwise direction or in a clockwise direction. 
     In addition, a polishing pad  30  may be installed on a top surface of the turntable  20 , and the polishing pad  30  may be, for example, a hard polyurethane pad. 
     The wafer carrier  40  may have the shape of a circular plate with a smaller diameter than that of the polishing pad  30 . A wafer W can be mounted on the wafer carrier  40 . The wafer W mounted on the wafer carrier  40  may be rotated while touching the polishing pad  30 . While a planarization process for the wafer W is in progress, CMP may be performed using slurry dispensed from the slurry dispensing unit  50 . Further, the slurry dispensing unit  50  may be disposed so as to be able to dispense the slurry towards a center portion of the turntable  20  (or the polishing pad  30 ). Accordingly, the dispensed slurry may be evenly distributed onto the polishing pad  30  by the centrifugal force. 
     The polishing pad conditioning apparatus  100  may be an apparatus for conditioning a polishing surface of the polishing pad  30 . The polishing pad conditioning apparatus  100  can keep the surface roughness of the polishing surface of the polishing pad  30  in an optimal condition by polishing the polishing surface. For example, the polishing pad conditioning apparatus  100  may control (i.e., to restore or to maintain) the surface roughness of the wafer W, by polishing the polishing pad  30  while the polishing pad  30  polishes the wafer W, or after polishing of the wafer W has stopped. 
       FIG.  2    illustrates a polishing pad conditioning apparatus  100  according to an example embodiment,  FIG.  3    illustrates an exploded perspective view of a head unit  160  of a polishing pad conditioning apparatus  100  according to an example embodiment, and  FIG.  4    is a cross-sectional view taken along line X-X′ of  FIG.  2    illustrating a head unit  160  and a pivot arm  140 . 
     Referring to  FIG.  2    to  FIG.  4   , the polishing pad conditioning apparatus  100  includes, for example, an apparatus body  120 , a pivot arm  140 , and a head unit  160 . 
     The apparatus body  120  may be disposed in proximity to the turntable  20 . The apparatus body  120  may be provided with a main motor (not illustrated) for rotating the pivot arm  140  in a circumferential direction R of the apparatus body  120 . Further, the apparatus body  120  may be provided with an air cylinder (not illustrated) for moving the head unit  160  towards the polishing pad  30  provided on the turntable  20  or for moving the head unit  160  away from the polishing pad  30 . 
     More specifically, by the main motor and the air cylinder provided on the apparatus body  120 , the pivot arm  140  may be rotated in a circumferential direction of the apparatus body  120 , thereby rotating about a pivot center of the apparatus body  120 . 
     The pivot arm  140  may be installed on the apparatus body  120 , and in particular, may be installed on the apparatus body  120  so as to be rotatable about the pivot center. For example, the pivot arm  140  may include a mounting part  142  mounted on the apparatus body  120 , an arm part  144  extending from the mounting part  142  in a radial direction of the apparatus body  120 , and a housing  146  disposed at a distal end portion of the arm part  144 . In particular, the pivot center (not illustrated) may be disposed inside the mounting part  142 . The pivot arm  140  may be formed of metal material. 
     Also, the arm part  144  may be provided with a sensor mounting part  144   a  in which a sensor  180  is installed. The sensor  180  installed in the sensor mounting part  144   a  may detect and assess the roughness of the polishing surface of the polishing pad  30 . For example, the sensor mounting part  144   a  may be disposed in proximity to the housing  146 . The arm part  144  may be formed as a hollow pipe, and a fluid flow tube  102  for guiding of fluid and various wires may pass through the inside of the arm part  144 . 
     Further, the housing  146  has an internal space. For example, a lower end portion of the housing  146  may be provided with a reduced diameter part  146   a  having a smaller diameter than that of an upper portion of the housing  146  as shown in  FIG.  4   . Also, the housing  146  may include a fluid flow path  146   b  through which the fluid flows to be discharged from the housing  146 . In particular, the fluid supplied from the fluid flow tube  102  passing through the arm unit  144  may flow inside the fluid flow path  146   b . In the example embodiment, the fluid flowing through the fluid flow path  146   b  may be air, an inert gas (for example, nitrogen gas, argon gas, etc.), or water. Also, the fluid flowing through the fluid flow path  146   b  may be discharged from the housing  146  through a space formed by an inner surface of the reduced diameter part  146   a  and an outer surface of a foreign material blocking member  164 . Accordingly, foreign objects can be prevented from entering the reduced diameter part  146   a  of the housing  146  from the exterior thereof. 
     The head unit  160  may be disposed at the distal end portion of the pivot arm  140 . For example, the head unit  160  may include a rotary motor  162  provided in the housing  146 , the foreign material blocking member  164 , a deformation member  166 , a disk holder  168 , and a conditioning disk  170 . 
     The rotary motor  162  may be installed in the housing  146  so as to be disposed in the internal space of the housing  146  of the pivot arm  140 . Further, the rotary motor  162  may be provided with a rotary shaft  162   a  to which the foreign material blocking member  164  is detachably attached. The rotary motor  162  serves to generate a rotational force for rotating the foreign material blocking member  164 , the deformation member  166 , and the conditioning disk  170  along with the disk holder  168 . 
     The foreign material blocking member  164  may be installed on the rotary shaft  162   a  of the rotary motor  162 . In particular, the foreign material blocking member  164  may be disposed at the reduced diameter portion  146   a  of the housing  146 . In addition, on the outer surface of the foreign material blocking member  164 , the fluid flow groove  164   a  may be formed to guide the fluid in order to prevent foreign objects from entering through the reduced diameter portion  146   a  of the housing  146 . For example, the fluid flow groove  164   a  may have a spiral shape or a curved shape, and these shape of the fluid flow groove  164   a  may be disposed facing towards a rotational direction of the foreign material blocking member  164 . Accordingly, through the spiral-shaped fluid flow groove  164   a , a fluid movement from the inside of the housing  146  to the exterior of the housing  146  may be created. Thus, foreign objects can be prevented from entering through the reduced diameter portion  146   a  of the housing  146  from the exterior thereof. For example, the (spiral-shaped or curved) fluid flow groove  164   a  may be formed to have a predetermined width w and depth d. For example, the (spiral-shaped or curved) fluid flow groove  164   a  may be formed to have a uniform width w and depth d. The example embodiments of the fluid flow groove  164   a  will be described in more detail below. 
     Referring to  FIG.  3   , the deformation member  166  may be disposed between the foreign material blocking member  164  and the disk holder  168 . For example, the deformation member  166  may be manufactured integrally with the foreign material blocking member  164  and the disk holder  168 , or may be manufactured separately and then assembled with the foreign material blocking member  164  and the disk holder  168 . Also, the deformation member  166  may include a deformation groove  166   a  for deformation of the deformation member  166  when an external force is applied to an outer surface thereof. For example, the deformation groove  166   a  may include a first deformation groove  166   a - 1  formed horizontally to the rotary shaft  162   a  and a second deformation groove  166   a - 2  disposed perpendicularly to the first deformation groove  166   a - 1 . 
     For example, the first deformation groove  166   a - 1  may be provided in plurality, and the plurality of first deformation grooves  166   a - 1  may be disposed in an axial direction and may be spaced apart from each other in a circumferential direction of the deformation member  166 . The second deformation groove  166   a - 2  may extend from the first deformation grooves  166   a - 1 , and a plurality of second deformation grooves  166   a - 2  may extend from a single first deformation groove  166   a - 1 . 
     As described above, because the first and second deformation grooves  166   a - 1  and  166   a - 2  are formed in the deformation member  166 , upon application of an external force, the deformation member  166  can be easily deformed with six degrees of freedom (three axial directions, and rotational directions around the three axial directions). To this end, the deformation member  166  may be made of an elastic material. For example, the deformation member  166  may be made of various materials, such as composite material, synthetic resin, and metal. 
     Accordingly, the deformation member  166  can reduce the uneven wear of the conditioning disk  170  and can further reduce damage to the disk holder  168 . In other words, when an external force is applied to the deformation member  166 , the deformation member  166  can reduce the shock or impact through deformation, and the conditioning disk  170  may be maintained to be perpendicularly in contact with the polishing pad  30 . 
     Although in this example embodiment, the deformation groove  166  is described as including only the first and second deformation grooves  166   a - 1  and  166   a - 2 , the deformation groove  166  may further include a third deformation groove (not shown) which is formed obliquely with respect to the first deformation groove  166   a - 1 . 
     The disk holder  168  may be disposed below the deformation member  166  and may be connected to the rotary shaft  162   a  by means of the deformation member  166  and the foreign material blocking member  164 . The disk holder  168  may have the shape of a circular plate. Also, the disk holder  168  may be formed of material with a larger weight than that of the deformation member  166 . 
     The conditioning disk  170  may be affixed to the disk holder  168 . Polishing particles, such as artificial diamond particles for example, may be evenly fixed onto a circular disk by means of a nickel (Ni) bonding layer. 
     As described above, the uneven wear of the conditioning disk  170  may be reduced through the deformation member  166 . Further, damage to the disk holder  168  may be reduced through the deformation member  166 . 
     A fluid movement from the inside of the housing  146  to the exterior thereof may be created through the foreign material blocking member  164 , thereby preventing foreign objects from entering the housing  146  through the reduced diameter portion  146   a  of the housing  146 . In other words, the fluid movement created through the fluid flow groove  164   a  formed on the outer surface of the foreign material blocking member  164  may serve to prevent the foreign objects from entering the housing  146 . 
     Furthermore, by causing the fluid flowing through the fluid flow path  146   b  to be discharged from the housing  146 , foreign objects can be further prevented from entering the housing  146  from the exterior thereof. 
     Hereinbelow, example embodiments of the fluid flow groove  164   a  of the foreign material blocking member  164  will be described in conjunction with drawings. 
       FIG.  5    is an enlarged view illustrating an example embodiments of a fluid flow groove  164   a - 1 . 
     Referring to  FIG.  5   , the fluid flow groove  164   a - 1  may have a spiral shape, and the spiral shape of the fluid flow groove  164   a - 1  may be disposed facing towards a rotational direction of the foreign material blocking member  164 . Accordingly, the fluid movement of the fluid to the exterior of the housing  146  from the inside of the housing  146  may be created through the spiral-shaped fluid flow groove  164   a - 1 . Thus, foreign materials can be prevented from entering the housing  146  from the exterior thereof. For example, the fluid flow groove  164   a - 1  may be formed to have width w 1  at an upper end portion of the outer surface of the foreign material blocking member  164  being smaller than width w 2  at a lower end portion of the outer surface of the foreign material blocking member  164 . In other words, the width of the fluid flow groove  164   a - 1  may be formed to increase from the upper end portion to the lower end portion. Accordingly, the pressure at the upper end portion of the outer surface of the foreign material blocking member  164  may be greater than the pressure at the lower end portion of the outer surface of the foreign material blocking member  164 . Consequently, in the foreign material blocking member  164 , the fluid may flow from the upper end portion of greater pressure, towards the lower end portion of lesser pressure due to the pressure difference. 
       FIG.  6    is an enlarged view of another one of the modified embodiments of the fluid flow groove. 
     Referring to  FIG.  6   , the fluid flow groove  164   a - 2  may have a spiral shape, and the spiral shape of the fluid flow groove  164   a - 2  may be disposed facing towards a rotational direction of the foreign material blocking member  164 . The fluid movement from the inside of the housing  146  to the outside of the housing  146  may be created through the spiral-shaped fluid flow groove  164   a - 2 . Accordingly, foreign objects can be prevented from entering the housing  146  from the exterior thereof. For example, the fluid flow groove  164   a - 2  may be formed to have depth d 1  at an upper end portion of the outer surface of the foreign material blocking member  164  being less than depth d 2  at a lower end portion of the outer surface of the foreign material blocking member  164 . In other words, the depth of the fluid flow groove  164   a - 2  may be formed to increase from the upper end portion to the lower end portion. Accordingly, the pressure at the upper end portion of the outer surface of the foreign material blocking member  164  may be greater than the pressure at the lower end portion of the outer surface of the foreign material blocking member  164 . Consequently, in the foreign material blocking member  164 , the fluid can flow from the upper end portion of greater pressure towards the lower end portion of lesser pressure due to the pressure difference. Meanwhile, width w 1  at an upper end portion of the fluid flow groove  164   a - 2  is substantially identical to width w 2  at a lower end portion of the fluid flow groove  164   a - 2 . 
       FIG.  7    is an enlarged view of another example embodiments of the fluid flow groove  164   a - 3 . 
     Referring to  FIG.  7   , a fluid flow groove  164   a - 3  may have a linear shape and may be formed in a direction parallel to the axial direction of the rotary shaft  162   a . In other words, the fluid flow groove  164   a - 3  may be formed in an axial direction of the foreign material blocking member  164 . Through the fluid flow groove  164   a - 3 , provided in plurality and spaced apart from one another in a circumferential direction on the outer surface of the foreign material blocking member  164 , a fluid movement from the inside of the housing  146  to the outside of the housing  146  may be created. Accordingly, foreign objects can be prevented from entering the housing  146  from the exterior thereof. For example, the fluid flow groove  164   a - 3  may be designed to have a predetermined width w and depth d. For example, the fluid flow groove  164   a - 3  may be formed to have an overall uniform width w and depth d. 
       FIG.  8    is an enlarged view of yet another example embodiments of the fluid flow groove  164   a - 4 . 
     Referring to  FIG.  8   , a fluid flow groove  164   a - 4  may have a linear shape and may be formed in a direction parallel to the extending direction of the rotary shaft  162   a . In other words, the fluid flow groove  164   a - 4  may be formed in an axial direction of the foreign material blocking member  164 . Accordingly, through the fluid flow groove  164   a - 4 , provided in plurality and spaced apart from one another in a circumferential direction on the outer surface of the foreign material blocking member  164 , a fluid movement from the inside of the housing  146  to the outside of the housing  146  may be created. Accordingly, foreign objects can be prevented from entering the housing  146 . For example, the fluid flow groove  164   a - 4  may be formed to have a width w 1  at an upper end portion of the outer surface of the foreign material blocking member  164  being smaller than a width w 2  at a lower end portion of the outer surface of the foreign material blocking member  164 . In other words, the width of the fluid flow groove  164   a - 4  may be formed to increase from the upper end portion towards the lower end portion. Accordingly, the pressure at the upper end portion of the outer surface of the foreign material blocking member  164  may be greater than the pressure at the lower end portion of the outer surface of the foreign material blocking member  164 . Consequently, in the foreign material blocking member  164 , the fluid can flow from the upper end portion of greater pressure towards the lower end portion of lesser pressure. 
       FIG.  9    is an enlarged view of yet another example embodiments of the fluid flow groove  164   a - 5 . 
     Referring to  FIG.  9   , a fluid flow groove  164   a - 5  may have a linear shape and may be formed in a direction parallel to the extending direction of the rotary shaft  162   a . In other words, the fluid flow groove  164   a - 5  may be formed in an axial direction of the foreign material blocking member  164 . Accordingly, through the fluid flow groove  164   a - 5 , provided in plurality and spaced apart from one another in a circumferential direction on the outer surface of the foreign material blocking member  164 , a fluid movement from the inside of the housing  146  to the outside of the housing  146  can be created. Accordingly, foreign objects can be prevented from entering the housing  146  from the exterior thereof. For example, the fluid flow groove  164   a - 5  may be formed to have depth d 1  at an upper end portion of the outer surface of the foreign material blocking member  164  being less than depth d 2  at a lower end portion of the outer surface of the foreign material blocking member  164 . In other words, the depth of the fluid flow groove  164   a - 5  may be formed to increase from the upper end portion towards the lower end portion. Accordingly, the pressure at the upper end portion of the outer surface of the foreign material blocking member  164  may be greater than the pressure at the lower end portion of the outer surface of the foreign material blocking member  164 . Consequently, in the foreign material blocking member  164 , a fluid can flow from the upper end portion of greater pressure towards the lower end portion of lesser pressure. 
     According to example embodiments of the present inventive concept, there may be provided a polishing pad conditioning apparatus capable of preventing foreign objects from entering a housing of the apparatus and moving towards a rotary motor rotating a conditioning disk. 
     Furthermore, according to example embodiments of the present inventive concept, there may be provided a polishing pad conditioning apparatus capable of reducing uneven wear of a conditioning disk and reducing damage to a structure having the conditioning disk installed thereon. 
     While example embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present inventive concept as defined by the appended claims.