Patent Publication Number: US-9833876-B2

Title: Polishing apparatus and polishing method

Description:
BACKGROUND 
     Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon. Many integrated circuits are typically manufactured on a single semiconductor wafer, and individual dies on the wafer are singulated by sawing between the integrated circuits along a scribe line. The individual dies are typically packaged separately, in multi-chip modules, or in other types of packaging, for example. 
     After the material is deposited on the wafer by a chemical vapor deposition (CVD) process, for example, the wafer is polished by a chemical mechanical polishing (CMP) process in a CMP apparatus. Although existing devices and methods for CMP process have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. Consequently, it would be desirable to provide a solution for polishing wafers in CMP apparatuses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure, and the advantages of the present disclosure, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic view of a polishing apparatus in accordance with some embodiments of the disclosure. 
         FIG. 2  is a side view of a polishing apparatus in accordance with some embodiments of the disclosure. 
         FIG. 3  is a top view of a dispensing device in accordance with some embodiments of the disclosure. 
         FIG. 4  is a flow chart of a polishing method in accordance with some embodiments of the disclosure. 
         FIGS. 5A to 5F  are top views or side views of the polishing apparatus during processes in accordance with some embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The making and using of various embodiments of the disclosure are discussed in detail below. It should be appreciated, however, that the various embodiments can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative, and do not limit the scope of the disclosure. 
     It should be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of the disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. Moreover, the performance of a first process before a second process in the description that follows may include embodiments in which the second process is performed immediately after the first process, and may also include embodiments in which additional processes may be performed between the first and second processes. Various features may be arbitrarily drawn in different scales for the sake of simplicity and clarity. Furthermore, the formation of a first feature over or on a second feature in the description may include embodiments in which the first and second features are formed in direct or indirect contact. 
     Some variations of the embodiments are described. It is understood that additional operations can be provided before, during, and after the method, and some of the operations described can be replaced or eliminated for other embodiments of the method. 
     Embodiments of a polishing apparatus are provided. The polishing apparatus is configured to polish wafers on a polishing pad by a polish process and clean particles remaining on the polishing pad. 
       FIG. 1  is a schematic view of a polishing apparatus  1  in accordance with some embodiments of the disclosure.  FIG. 2  is a side view of the polishing apparatus  1  in accordance with some embodiments of the disclosure. In some embodiments, the polishing apparatus  1  is a chemical mechanical polishing (CMP) apparatus. The polishing apparatus  1  is configured to polish a wafer W 1 . The polishing apparatus  1  includes a base  10 , a polishing device  20 , a first dispensing device  30 , a second dispensing device  40 , a retaining device  50 , and a roughening device  60 . 
     The polishing device  20  is disposed on the base  10 . The polishing device  20  is configured to polish the wafer W 1 . The polishing device  20  includes a polishing pad  21  and a rotation mechanism  22 . The polishing pad  21  is configured to polish the wafer W 1 . The polishing pad  21  is disposed on the rotation mechanism  22 . The rotation mechanism  22  is disposed on the base  10 . The rotation mechanism  22  is configured to rotate the polishing pad  21 . 
     In some embodiments, the diameter of the polishing pad  21  is about two times to about four times of the diameter of the wafer W 1 . In some embodiments, the wafer W 1  has a diameter in a range from about 200 mm to about 600 mm. For example, the wafer W 1  has a diameter about 300 mm or 450 mm. In some embodiments, the polishing pad  21  has a diameter in a range from about 400 mm to 2000 mm. For example, the polishing pad  21  has a diameter in a range from about 600 mm to about 1000 mm. 
     As shown in  FIGS. 1 and 2 , the first dispensing device  30  is disposed on the base  10 . The first dispensing device  30  is configured to dispense slurry and washing liquid onto a polishing surface  211  of the polishing pad  21 . In some embodiments, the washing liquid is water or deionized water. The first dispensing device  30  includes a first support  31 , a first dispensing arm  32 , a number of first liquid nozzles  33 , and a number of slurry nozzles  34 . The first support  31  is disposed on the base  10 . 
     The first dispensing arm  32  is disposed on the first support  31 . The first dispensing arm  32  is located over the polishing pad  21 . In some embodiments, the first dispensing arm  32  is a linear structure extended along a first extension axis AX 1 . In some embodiments, the first extension axis AX 1  is parallel to the polishing surface  211 . The first extension axis AX 1  substantially passes though the center of the polishing pad  21 . In some embodiments, the first dispensing arm  32  is a telescoping dispensing arm. 
     The first liquid nozzles  33  are disposed on the first dispensing arm  32 . In some embodiments, the first liquid nozzles  33  are arranged on the first dispensing arm  32  along an extension direction D 1 . In some embodiments, the extension direction D 1  is parallel to the first extension axis AX 1 . The first liquid nozzles  33  are configured to dispense washing liquid onto the polishing surface  211 . In some embodiments, the washing liquid is water or deionized water. 
       FIG. 3  is a top view of the first dispensing device  30  in accordance with some embodiments of the disclosure. As show in  FIGS. 2 and 3 , in some embodiments, each of the first liquid nozzles  33  faces different directions. Therefore, the first liquid nozzles  33  dispense washing liquid toward different directions. In some embodiments, each of the angles of the first liquid nozzles  33  is adjustable. In some embodiments, at least two of the first liquid nozzles  33  face the same direction. In some embodiments, all of the first liquid nozzles  33  face the same direction. 
     For example, in some embodiments, the first liquid nozzles  33  are respectively extended along the dispensing directions D 2   a , D 2   b , D 2   c , D 2   d  and D 2   e . The openings  331  of the first liquid nozzles  33  are respectively perpendicular to the dispensing directions D 2   a  to D 2   e . The first liquid nozzles  33  respectively dispense the washing liquid onto the polishing surface  211  along dispensing directions D 2   a  to D 2   e.    
     The dispensing directions D 2   a  to D 2   e  have acute angles A 1  with respect to the polishing surface  211 . The acute angles A 1  are in a range from about 20 degrees to about 80 degrees. As shown in  FIGS. 2 and 3 , the dispensing directions D 2   a  to D 2   e  are different to each other. In some embodiments, at least two of the dispensing directions D 2   a  to D 2   e  are the same. In some embodiments, all of the dispensing directions D 2   a  to D 2   e  are the same. 
     The dispensing directions D 2   a  to D 2   e  have horizontal components D 3   a , D 3   b , D 3   c , D 3   d  and D 3   e  (the horizontal components D 3   a  to D 3   e  are illustrated under the dispensing directions D 2   a  to D 2   e  in  FIG. 3 ). The horizontal angles A 2  between the first extension axis AX 1  and the horizontal components D 3   a  to D 3   e  are in a range from about 10 degrees to about 160 degrees. 
     As shown in  FIG. 3 , the horizontal components D 3   a  to D 3   e  are different. The horizontal angles A 2  of the horizontal components D 3   a  to D 3   e  of the first liquid nozzles  33  are gradually and progressively greater from the first liquid nozzle  33  adjacent to the edge of the polishing pad  21  to the first liquid nozzle  33  adjacent to the center of the polishing pad  21 . 
     In some embodiments, the horizontal component D 3   a  of the first liquid nozzle  33  adjacent to the edge of the polishing pad  21  is in a range from about 10 degrees to about 60 degrees. In some embodiments, the horizontal component D 3   e  of the first liquid nozzle  33  adjacent to the center of the polishing pad  21  is in a range from about 120 degrees to about 160 degrees. In some embodiments, at least two of the horizontal components D 3   a  to D 3   e  are the same. In some embodiments, all of the horizontal components D 3   a  to are the same. 
     The slurry nozzles  34  are disposed on the first dispensing arm  32 . The slurry nozzles  34  are configured to dispense slurry on the polishing surface  211 . In some embodiments, the slurry nozzles  34  are located at the end of the first dispensing arm  32  adjacent to the center of the polishing pad  21 . In some embodiments, the first dispensing device  30  includes one slurry nozzle  34 . In some embodiments, the slurry includes polishing powder. 
     As shown in  FIG. 1 , the second dispensing device  40  is disposed on the base  10 . In some embodiments, the first and the second dispensing devices  30  and  40  are located at two opposite sides of the polishing pad  21 . In some embodiments, the structure of the second dispensing device  40  is substantially the same as the structure of the first dispensing device  30 . 
     The second dispensing device  40  is configured to dispense washing liquid onto the polishing surface  211  of the polishing pad  21 . The second dispensing device  40  includes a second support  41 , a second dispensing arm  42 , and a number of second liquid nozzles  43 . The second support  41  is disposed on the base  10 . 
     The second dispensing arm  42  is disposed on the second support  41 . The second dispensing arm  42  is located over the polishing pad  21 . In some embodiments, the second dispensing arm  42  is a linear structure extended along a second extension axis AX 2 . In some embodiments, the second extension axis AX 2  is parallel to the polishing surface  211 . The second extension axis AX 2  substantially passes though the center of the polishing pad  21 . In some embodiments, the second extension axis AX 2  overlaps the first extension axis AX 1 . In some embodiments, the second dispensing arm  42  is a telescoping dispensing arm. 
     The second liquid nozzles  43  are disposed on the second dispensing arm  42 . In some embodiments, the structure of the second liquid nozzles  43  is substantially the same as the structure of the first liquid nozzles  33 . In some embodiments, the second liquid nozzles  43  are arranged on the second dispensing arm  42  along the extension direction D 1 . 
     The second liquid nozzles  43  are configured to dispense the washing liquid onto the polishing surface  211 . In some embodiments, each of the angles of the second liquid nozzles  43  is adjustable. Since the angles and the directions of the second liquid nozzles  43  is similar to the angles and the directions of the first liquid nozzles  33  as shown in  FIGS. 2 and 3 , the further description of the angles and the directions of the second liquid nozzles  43  is omitted for sake of brevity. 
     As shown in  FIG. 1 , the retaining device  50  is disposed on the base  10 . The retaining device  50  is configured to dispose the wafer W 1  on the polishing surface  211 . The retaining device  50  includes a first moving mechanism  51 , a first rotation element  52 , and a retaining element  53 . The first moving mechanism  51  is disposed on the base  10 . The first moving mechanism  51  is configured to move the retaining element  53 . The first rotation element  52  is disposed on the first moving mechanism  51 . The first rotation element  52  is configured to rotate the retaining element  53 . 
     The retaining element  53  is disposed on the first rotation element  52 . The retaining element  53  is configured to retaining the wafer W 1 . In some embodiments, the retaining element  53  is a sucking disc. The retaining element  53  retains the wafer W 1  by drawing the upper surface of the wafer W 1 . The area of the retaining element  53  is substantially the same as the wafer W 1 . 
     As shown in  FIG. 1 , the roughening device  60  is disposed on the base  10 . The roughening device  60  is configured to roughen the polishing surface  211 . The roughening device  60  includes a second moving mechanism  61 , a second rotation element  62 , and a roughening disk  63 . The second moving mechanism  61  is disposed on the base  10 . The second moving mechanism  61  is configured to move the roughening disk  63 . The second rotation element  62  is disposed on the second moving mechanism  61 . The second rotation element  62  is configured to rotate the roughening disk  63 . 
     The roughening disk  63  is disposed on the second rotation element  62 . The roughening disk  63  is configured to roughen the polishing surface  211 . In some embodiments, the roughening disk  63  includes a hardness material on a lower surface of the roughening disk  63 . In some embodiments, the hardness material includes a number of diamond particles. The lower surface contacts or faces the polishing surface  211  during a roughening process. 
       FIG. 4  is a flow chart of a polishing method in accordance with some embodiments of the disclosure.  FIG. 5A  is a top view of the polishing apparatus  1  during a polishing process in accordance with some embodiments of the disclosure.  FIG. 5B  is a side view of the polishing apparatus  1  during the polishing process in accordance with some embodiments of the disclosure. As shown in  FIGS. 4, 5A and 5B , in step S 101 , the polishing pad  21  is rotated by the rotation mechanism  22 . The rotational speed of the polishing pad  21  is in a range from about 50 rpm to about 120 rpm. 
     In the step S 103 , the first dispensing device  30  dispenses slurry L 1  onto the center area of the polishing surface  211  of the polishing pad  21  via the slurry nozzle  34 . Sine the polishing pad  21  is rotated, the slurry L 1  is distributed on the polishing surface  211  by a centrifugal force. In some embodiments, the position of the slurry nozzle  34  is changed by adjusting the length of the first dispensing arm  32 . Therefore, the slurry L 1  is uniformly dispensed onto the polishing surface  211 . 
     In the step S 105 , the wafer W 1  is disposed on the polishing surface  211  by the retaining device  50 . A lower surface of the wafer W 1  facing the polishing surface  211  is polished by the polishing pad  21  during the polish process. The slurry L 1  is continually dispensed by the first dispensing device  30  during polishing the wafer W 1 . In general, the polishing surface  211  is rough. The wafer W 1  is polished by the polishing surface  211  by the relative movement between the wafer W 1  and the polishing pad  21 . 
     In some embodiments, the first moving mechanism  51  moves the wafer W 1  on the polishing surface  211  as shown in  FIGS. 5A and 5B . Afterwards, the wafer W 1  is rotated on the polishing surface  211  by the first rotation element  52 . In some embodiments, the rotational speed of the wafer W 1  is in a range from about 50 rpm to about 120 rpm. 
     Furthermore, the wafer W 1  is pressed on the polishing surface  211  by the first moving mechanism  51 . In some embodiments, the force applied on the wafer W 1  by the first moving mechanism  51  is in a range from about 50 nt to about 500 nt. 
       FIG. 5C  is a top view of the polishing apparatus  1  during a cleaning process in accordance with some embodiments of the disclosure.  FIG. 5D  is a side view of the polishing apparatus  1  during the cleaning process in accordance with some embodiments of the disclosure. In the step  107 , as shown in  FIG. 5C  and  FIG. 5D , the wafer W 1  is removed from the polishing surface  211  by the first moving mechanism  51  after the wafer W 1  is polished. 
     In general, there some particles P 1  are remained on the polishing pad  21  after the wafer W 1  is polished. In the step S 109 , the first and the second dispensing devices  40  dispense the washing liquid onto the polishing surface  211  after the wafer W 1  is removed. During the washing liquid is dispensed, the polishing pad  21  is continually rotated. Therefore, the particles P 1  are washed away by the washing liquid. In some embodiments, by the dispensing directions of the washing liquid, the force of the washing liquid impacting the particles P 1  on the polishing surface  211  is increased. Furthermore, since the first and the second liquid nozzles  33  and  43  are located over two opposite sides of the center of the polishing surface  211 , the washing liquid flows through most area of the polishing surface  211 . Therefore, the cleanness efficiency of the polishing pad  21  is improved. 
     In some embodiments, the position of the first and the second liquid nozzles  33  and  43  are changed by adjusting the length of the first and the second dispensing arms  32  and  42  to improve the cleanness efficiency of the polishing pad  21 . 
     In general, after the wafer W 1  is polished on the polishing surface  211 , the roughness of the polishing surface  211  is decreased. Therefore, the roughening disk  63  is used to increase the roughness of the polishing surface  211 . 
       FIG. 5E  is a top view of the polishing apparatus  1  during the roughening process in accordance with some embodiments of the disclosure.  FIG. 5F  is a side view of the polishing apparatus  1  during the roughening process in accordance with some embodiments of the disclosure. In the step S 111 , the roughening disk  63  is disposed on the polishing surface  211  by the second moving mechanism  61  to roughen the polishing surface  211 . 
     The roughening disk  63  is rotated by the second rotation element  62 . In some embodiments, the rotational speed of the roughening disk  63  is in a range from about 20 rpm to about 80 rpm. Furthermore, the roughening disk  63  is pressed on the polishing surface  211  by the second moving mechanism  61 . In some embodiments, the force applied on the roughening disk  63  by the second moving mechanism  61  is in a range from about 100 nt to about 800 nt. 
     Since the lower surface of the roughening disk  63  has hardness material, such as diamond particles, the polishing surface  211  is roughed by the relative movement between the roughening disk  63  and the polishing pad  21 . 
     When the polishing surface  211  is roughed by the roughening disk  63 , there are some particles P 1  are generated on the polishing surface  211 . Therefore, the first and the second dispensing devices  40  dispense the washing liquid on the polishing surface  211 . Furthermore, the polishing pad  21  is rotated. The particles P 1  are washed away by the washing liquid. 
     In the step S 113 , the roughening disk  63  is removed from the polishing surface  211  by the second moving mechanism  61 . The first and the second dispensing devices  40  stop dispensing the washing liquid onto the polishing surface  211 . 
     Embodiments of a polishing apparatus are provided. The polishing apparatus includes a number of dispensing devices. The dispensing devices dispense washing liquid on a polishing surface of a polishing pad. In some embodiments, the dispensing devices are located at two opposite sides of the polishing pad. Therefore, the washing liquid flows through most area of the polishing surface, and the particles on the polishing surface are washed by the washing liquid. Furthermore, the dispensing devices dispense washing liquid onto the polishing surface along dispensing directions. The dispensing directions have acute angles with respect to the polishing surface. Therefore, the force of the washing liquid impacting the particles on the polishing surface is increased. The cleanness efficiency of the polishing pad is improved. 
     In some embodiments, the polishing apparatus is provided. The polishing apparatus includes a polishing pad having a polishing surface. The polishing apparatus also includes a dispensing device including a dispensing arm located over the polishing pad and a liquid nozzle disposed on the dispensing arm. The liquid nozzle is configured to dispense washing liquid onto the polishing surface along a dispensing direction. The dispensing direction has an acute angle with respect to the polishing surface. 
     In some embodiments, the polishing apparatus is provided. The polishing apparatus includes a polishing pad having a polishing surface. The polishing apparatus also includes a first dispensing device including a first dispensing arm located over the polishing pad and a first liquid nozzle, disposed on the first dispensing arm. The first liquid nozzle is configured to dispense washing liquid onto the polishing surface along a first dispensing direction. The polishing apparatus further includes a second dispensing device including a second dispensing arm located over the polishing pad and a second liquid nozzle disposed on the second dispensing arm. The second liquid nozzle is configured to dispense washing liquid onto the polishing surface along a second dispensing direction. The first dispensing direction has a first acute angle with respect to the polishing surface, and the second dispensing direction has a second acute angle with respect to the polishing surface. 
     In some embodiments, the polishing method is provided. The polishing method includes rotating a polishing pad and dispensing slurry on a polishing surface of the polishing pad. The polishing method also includes disposing a wafer on the polishing surface and removing the wafer from the polishing surface. The polishing method further includes dispensing washing liquid on the polishing surface along a first dispensing direction via a first liquid nozzle of a first dispensing arm. The first dispensing direction has a first acute angle with respect to the polishing surface. 
     Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. For example, it will be readily understood by those skilled in the art that many of the features, functions, processes, and materials described herein may be varied while remaining within the scope of the present disclosure. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. In addition, each claim constitutes a separate embodiment, and the combination of various claims and embodiments are within the scope of the disclosure.