JP4790322B2 - Processing apparatus and processing method - Google Patents

Description

  The present invention relates to a processing apparatus and a processing method, and more particularly, to a processing apparatus including a polishing unit that chemically and mechanically polishes the surface of a workpiece, and a processing method using the same.

  In a semiconductor device manufacturing process, a plurality of rectangular areas are defined by scheduled cutting lines called streets arranged in a grid on the surface of a semiconductor wafer having a substantially disk shape, and a semiconductor circuit is formed in each of the rectangular areas. . Individual semiconductor chips are formed by separating the semiconductor wafer on which a plurality of semiconductor circuits are formed in this way along the streets. An optical device wafer is divided into a plurality of regions by streets formed in a lattice pattern on the surface of a sapphire substrate or the like, and an optical device in which a gallium nitride compound semiconductor or the like is laminated is formed in the partitioned regions. Yes. Such optical device wafers are separated into optical devices such as individual light emitting diodes and laser diodes along the planned separation line, and are widely used in electrical equipment.

  As described above, in order to reduce the size and weight of individual semiconductor chips, the back surface of the semiconductor wafer is usually cut prior to cutting the semiconductor wafer along the streets and separating the semiconductor chips into individual semiconductor chips. Is formed to a predetermined thickness. The grinding of the back surface of the semiconductor wafer is usually performed by pressing diamond grinding grains against the back surface of the semiconductor wafer while rotating a grinding tool formed by bonding with a bond such as a resin bond at a high speed.

  When the back surface of the semiconductor wafer is ground by such a grinding method, processing strain such as microcracks is generated on the back surface of the semiconductor wafer, thereby reducing the bending strength of the individually separated semiconductor chips. Wet etching that chemically etches the back surface of the ground semiconductor wafer using an etchant containing nitric acid and hydrofluoric acid as a countermeasure to remove the processing strain generated on the back surface of the ground semiconductor wafer. A dry etching method using an etching method or an etching gas is used. Further, a CMP (Chemical Mechanical Polishing) method for polishing the back surface of a ground semiconductor wafer using loose abrasive grains has been put into practical use.

  By the way, there is a problem that the semiconductor wafer is damaged when the semiconductor wafer is transferred from the grinding device to the etching device or the polishing device in order to etch or polish the semiconductor wafer ground by the grinding device.

  In order to solve such a problem, for example, as described in Patent Document 1, a holding means for holding a semiconductor wafer, and a grinding means for grinding one surface of the semiconductor wafer held by the holding means, Has been proposed in which a polishing means for polishing a ground surface of a semiconductor wafer held by a holding means and ground by a grinding means has been proposed.

  In the flat surface processing apparatus described in Patent Document 1, CMP is performed using a polishing pad using loose abrasive grains as a polishing means. When such CMP is performed, the surface of the polishing pad is used. The surface of the polishing pad must be cleaned because clogging occurs. Therefore, the planar processing apparatus is provided with a polishing pad cleaning stage, and the polishing pad is periodically moved to clean the polishing pad.

JP 2000-254857 A

  However, in the case of the configuration of the flat surface processing apparatus described in Patent Document 1, a polishing pad cleaning stage must be separately provided in addition to the grinding stage and the polishing stage, so that the apparatus becomes large. was there.

  In addition, the polishing pad is usually cleaned between the polishing process and the next polishing process, and the next semiconductor wafer cannot be polished until the cleaning of the surface of the polishing pad is completed. Therefore, even if the grinding process of the semiconductor wafer to be polished next is completed and the semiconductor wafer is moved to the polishing position, the polishing process cannot be started immediately and a waiting time is required, resulting in a decrease in throughput. There was a problem. Further, in some cases, the polishing pad must be cleaned each time polishing of one semiconductor wafer is completed. In such a case, the waiting time is particularly long, so that the throughput is greatly reduced. Was.

  Accordingly, the present invention has been made in view of such problems, and its object is to prevent an increase in the size of the apparatus and to enable the polishing process to be started as soon as the semiconductor wafer grinding process is completed. It is an object of the present invention to provide a new and improved processing apparatus and a processing method using the same.

  As a result of intensive studies to solve the above problems, the present inventors have provided a polishing pad cleaning means in the vicinity of the chuck table located at the polishing position of the workpiece, and the polishing pad is cleaned at the end of the polishing process. It has been found that the simultaneous use of the water polishing step to be performed can prevent an increase in the size of the apparatus and improve the throughput, and the present invention has been completed based on this finding.

That is, according to one aspect of the present invention, there is provided a chuck table for holding a workpiece; a polishing pad having a larger diameter than the workpiece; and a processing liquid supply means for selectively supplying a polishing liquid and a cleaning liquid. Polishing means for polishing the workpiece by bringing a polishing pad into contact with the workpiece from the upper side of the workpiece held by the chuck table; in the vicinity of each of the plurality of chuck tables disposed on the turntable ; And a polishing pad cleaning means that is fixed on the table and cleans the surface of the polishing pad from below.

  In the above processing apparatus, the polishing means performs chemical mechanical polishing while supplying a polishing liquid to the processing surface of the workpiece held on the chuck table, and the polishing pad cleaning means includes the polishing pad in the radial direction of the polishing pad. The surface of the polishing pad is cleaned while moving relative to the surface.

The processing apparatus further includes a turntable provided with a plurality of chuck tables and rotatably provided; a grinding means for grinding a workpiece held on the chuck table; and a polishing means, you polished workpiece is ground by the grinding means.

  As described above, according to the processing apparatus according to the present invention, since the polishing pad cleaning means is provided in the vicinity of the chuck table located at the polishing position of the workpiece, a separate cleaning stage is not required. Can be prevented.

In the processing apparatus, the polishing pad cleaning means cleans the surface of the polishing pad when the processing liquid supply means stops supplying the polishing liquid and supplies the cleaning liquid (during a so-called water polishing process). you.

  Thus, according to the processing apparatus according to the present invention, the surface of the workpiece is cleaned at the same time by using the water polishing process for cleaning the surface of the workpiece performed at the end of the polishing process. When the process is completed, the next polishing process can be started immediately, the waiting time can be eliminated, and the throughput can be improved.

  The polishing pad cleaning means is configured to relatively move at least from the center to the outer periphery of the polishing pad. With this configuration, the front surface of the polishing pad can be cleaned if the polishing pad is rotating in the horizontal direction at the same time as the polishing pad cleaning means is relatively moving.

  The polishing pad cleaning means can be configured as, for example, a liquid ejecting means for ejecting liquid, a two-fluid ejecting means for mixing and ejecting liquid and gas, a brush means, and the like.

  According to another aspect of the present invention, in the processing method using the processing apparatus as described above, the polishing surface for polishing the workpiece held on the chuck table is applied to the processing surface of the workpiece. , By stopping the supply of the polishing liquid and supplying cleaning water, the above-mentioned processed surface is polished with the polishing pad, and the polishing pad cleaning means and the polishing pad are moved relative to each other in the radial direction so that the surface of the polishing pad is A processing method characterized by washing is provided.

  As described above, according to the processing method of the present invention, the surface of the polishing pad is simultaneously cleaned using the water polishing process for cleaning the surface of the semiconductor wafer performed at the end of the polishing process, so that the previous polishing process is completed. Then, the next polishing process can be started immediately, waiting time can be eliminated, and throughput can be improved.

  According to the present invention, the polishing pad cleaning means is provided in the vicinity of the chuck table located at the polishing position of the workpiece, and the polishing pad is cleaned simultaneously with the water polishing step performed at the end of the polishing step. It is possible to provide a processing apparatus and a processing method using the same that can prevent an increase in size and improve the throughput.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, the overall configuration of a semiconductor wafer processing apparatus 1 configured as an example of a processing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing the overall configuration of the semiconductor wafer processing apparatus 1 according to the present embodiment.

  As shown in FIG. 1, a semiconductor wafer processing apparatus 1 is configured as an apparatus that grinds the back surface of a semiconductor wafer 50, which is an example of a workpiece, and polishes the ground surface of the ground semiconductor wafer. Yes. The semiconductor wafer 50 is, for example, a substantially disc-shaped silicon wafer such as 8, 12 inches. The semiconductor wafer processing apparatus 1 grinds the back surface (surface opposite to the circuit surface on which the semiconductor elements are formed) of the semiconductor wafer 50 to reduce the thickness to, for example, 50 to 100 μm. Furthermore, the grinding surface (surface to be polished) of the semiconductor wafer 50 that has been thinned by grinding is polished and the ground surface is flattened (mirror finish) with high accuracy.

  Each component of the semiconductor wafer processing apparatus 1 will be specifically described. As shown in FIG. 1, a semiconductor wafer processing apparatus 1 includes, for example, a housing 2, a rough grinding unit 3, a finish grinding unit 4, a polishing unit 5, a polishing unit moving mechanism 6, a processing liquid supply unit 7, For example, four chuck tables 9 installed on the turntable 8, cassettes 11 and 12, a position table 13, a transfer arm 15, a robot pick 20, and a spinner cleaning device 30 are mainly provided.

  In the semiconductor wafer processing apparatus 1, in order to solve the problem that the semiconductor wafer is damaged or bent when the semiconductor wafer is transferred from the grinding apparatus to the polishing apparatus due to the increase in size and thickness of the semiconductor wafer, the grinding is performed. Both the means (grinding units 3 and 4) and the polishing means (polishing unit 5) are provided.

  The rough grinding unit 3 performs rough grinding on the back surface of the semiconductor wafer 50 by pressing the back surface of the semiconductor wafer 50 held on the chuck table 9 while rotating the grinding wheel 3b mounted on the lower end of the spindle 3a. . Similarly, the finish grinding unit 4 presses the back surface of the semiconductor wafer 50 after the rough grinding while rotating the grinding wheel 4b mounted on the spindle 4a, thereby causing the back surface of the semiconductor wafer 50 to be pressed. Finish grinding with high accuracy.

  The polishing unit 5 presses the back surface of the semiconductor wafer 50 after finish grinding held on the chuck table 9 while rotating the polishing pad 5b attached to the lower end of the spindle 5a, thereby rotating the back surface of the semiconductor wafer 50. Polishing. The polishing unit moving mechanism 6 moves the polishing unit 5 in the horizontal direction (the radial direction of the polishing pad 5b, the X-axis direction in FIG. 1) and the vertical direction (the axial direction of the spindle 5a, the Z-axis direction in FIG. 1). it can. Further, the processing liquid supply unit 7 selectively supplies the polishing liquid and the cleaning liquid to the processed surface of the semiconductor wafer 50 after the grinding process during the polishing process. The machining liquid supply unit 7 is connected to the upper end portion of the polishing unit 5 via the machining liquid supply path 72 and supplies the polishing liquid or the cleaning liquid to the polishing unit 5. The polishing unit 5, the polishing unit moving mechanism 6 and the machining liquid supply unit 7 constitute the polishing means according to this embodiment as a whole. Details of the polishing means will be described later.

  The turntable 8 is a disk-shaped table provided on the upper surface of the housing 2 and can be rotated in the horizontal direction. On the turntable 8, for example, four chuck tables 9 (9a to 9d) are arranged at equal intervals with a phase angle of 90 degrees, for example. The chuck table 9 has a vacuum chuck on its upper surface, and holds the semiconductor wafer 50 placed thereon by vacuum suction. The chuck table 9 can be rotated in the horizontal direction by a rotation drive mechanism (not shown) during grinding and polishing. The chuck table 9 having such a configuration is sequentially moved to the carry-in / carry-out area A, the rough grinding area B, the finish grinding area C, the polishing area D, and the carry-in / carry-out area A by the rotation of the turntable 8.

  The cassettes 11 and 12 are containers for semiconductor wafers having a plurality of slots. The cassette 11 accommodates the semiconductor wafer 50 before grinding, while the cassette 12 accommodates the semiconductor wafer 50 after polishing. The position table 13 is a table on which the semiconductor wafer 50 taken out from the cassette 11 is temporarily placed and its center is aligned.

  The transfer arm 15 is configured to be movable in the horizontal direction (Y-axis direction), and transfers the semiconductor wafer 50 before grinding that is placed on the position table 13 and is located in the carry-in / out area A. 9a. Further, the transfer arm 15 transfers the polished semiconductor wafer 50 placed on the chuck table 9 a located in the carry-in / out region A and places it on the spinner table of the spinner cleaning device 30.

  The robot pick 20 includes a wafer holder (for example, a U-shaped hand), and the semiconductor wafer 50 is sucked and held by the wafer holder and transferred. Specifically, the robot pick 20 carries the semiconductor wafer 50 before grinding from the cassette 11 to the position table 13. Further, the polished semiconductor wafer 50 is transferred from the spinner cleaning device 30 to the cassette 12.

  The spinner cleaning device 30 cleans the polished semiconductor wafer 50 and removes contamination such as grinding scraps and polishing scraps adhering to the ground and polished processed surface.

  Next, the operation of the semiconductor wafer processing apparatus 1 having the above configuration will be described. First, the robot pick 20 takes out one semiconductor wafer 50 before grinding, which is placed in the cassette 11, carries it, and places it on the position table 13. Next, the position table 13 aligns the center of the mounted semiconductor wafer 50. Further, the transfer arm 15 transfers the semiconductor wafer 50 aligned at the center and places it on the chuck table 9 arranged in the loading / unloading area A. The chuck table 9 holds the semiconductor wafer 50 placed thereon by vacuum suction.

  Next, the turntable 8 is rotated so that the chuck table 9 holding the semiconductor wafer 50 is moved to the rough grinding region B and positioned below the rough grinding unit 3. In this state, the back surface of the semiconductor wafer 50 is roughly ground by the rough grinding unit 3. Further, the turntable 8 is rotated, and the chuck table 9 holding the roughly ground semiconductor wafer 50 is moved to the finish grinding area C and positioned below the finish grinding unit 4. In this state, the back surface of the semiconductor wafer 50 is finish ground by the finish grinding unit 4. The grinding wheel 4b for finish grinding uses finer abrasive grains than the grinding wheel 3b for rough grinding, so that higher precision grinding is performed.

  After the finish grinding process is completed, the turntable 8 is further rotated, and the chuck table holding the semiconductor wafer 50 subjected to the finish grinding process is moved to the polishing region D and positioned below the polishing unit 5. In this state, the back surface of the semiconductor wafer 50 is polished by the polishing unit 5. This polishing process is performed in order to remove the work-affected layer of the semiconductor wafer 50 that has been subjected to finish grinding, and to mirror-finish the back surface of the semiconductor wafer 50. At the same time as this polishing process, another subsequent semiconductor wafer 50 is finish-ground by the finish grinding unit 4, and further another semiconductor wafer 50 is roughly ground by the rough grinding unit 3, thereby efficiently processing the wafer. Can be

  Next, the turntable 8 is further rotated, and the chuck table 9 holding the polished semiconductor wafer 50 is moved to the loading / unloading area A again. Next, the polished semiconductor wafer 50 is unloaded by the transfer arm 15 and transferred to the spinner cleaning device 30. The spinner cleaning device 30 cleans and removes the contamination adhering to the back surface (the ground and polished processed surface) of the semiconductor wafer 50. Thereafter, the robot pick 20 sucks and holds the cleaned semiconductor wafer 50 by the wafer holding unit, and accommodates the semiconductor wafer 50 in the cassette 12.

  In the semiconductor wafer processing apparatus 1, the semiconductor wafer 50 is ground and polished as described above. Polishing in the semiconductor wafer processing apparatus 1 is performed by CMP (Chemical Mechanical Polishing) in which polishing is performed with a polishing pad using loose abrasive grains as polishing means. Since clogging occurs on the surface of the polishing pad, the surface of the polishing pad must be cleaned.

  Recently, at the end of the polishing process, so-called water polishing is often performed in which the polishing liquid supplied at the time of polishing is switched to cleaning water and then supplied with the polishing pad in contact with the surface of the semiconductor wafer. . This water polishing is performed in order to reduce the burden of spinner cleaning performed later by dropping polishing debris to some extent from the surface of the semiconductor wafer. Normally, the polishing pad is cleaned after this water polishing.

  Therefore, the next semiconductor wafer 50 cannot be polished until the surface of the polishing pad 5b is cleaned. That is, even if the grinding process of the semiconductor wafer 50 to be polished next is completed and the semiconductor wafer 50 moves to the polishing region D, the polishing process cannot be started immediately, and a waiting time is required. There was a problem that decreased. Further, in some cases, the polishing pad 5b may have to be cleaned every time the polishing of one semiconductor wafer 50 is completed. In such a case, the waiting time is particularly long, and thus throughput is increased. It was greatly reduced.

  Therefore, in the polishing unit 5 of the semiconductor wafer processing apparatus 1 according to the present embodiment, the polishing pad cleaning means 40 (FIGS. 5 to 5 described later) is provided in the vicinity of the chuck table 9 located in the polishing region D where the semiconductor wafer 50 is polished. 7), and when the water polishing is performed, the surface of the polishing pad 5b is cleaned using the polishing pad cleaning means 40 at the same time. As a result, it is not necessary to provide a separate polishing pad cleaning stage as in the prior art. Also, when the next semiconductor wafer is polished after the water polishing step, the polishing pad cleaning has already been completed. Since the semiconductor wafer can be polished, the throughput can be improved.

  Hereinafter, based on FIGS. 2-4, the structure of the grinding | polishing means which concerns on this embodiment is demonstrated in detail. 2 and 3 are a perspective view and a side view, respectively, showing configurations of the polishing unit 5 and the polishing unit moving mechanism 6 according to the present embodiment, and FIG. 4 is a working fluid supply unit according to the present embodiment. 7 is an explanatory diagram showing an internal configuration of FIG.

  As described above, the polishing means according to the present embodiment mainly includes the polishing unit 5 that performs polishing on the back surface of the semiconductor wafer 50 after grinding, and the polishing that moves the polishing unit 5 in the horizontal direction and the vertical direction. The unit moving mechanism 6 and a processing liquid supply unit 7 for selectively supplying a polishing liquid and a cleaning liquid at the time of polishing are configured.

  The polishing unit 5 is disposed in the polishing region D and is configured to perform chemical mechanical polishing (CMP polishing) on the back surface of the semiconductor wafer 50. Specifically, as shown in FIGS. 2 and 3, the polishing unit 5 includes a spindle 5a and a polishing pad 5b attached to the tip of the spindle 5a. The polishing pad 5b has a larger diameter than the semiconductor wafer 50, and the polishing liquid is held on the chuck table 9 from a processing liquid supply path 72 (described later) for supplying a polishing liquid containing loose abrasive grains inside the polishing pad 5b. The back surface of the semiconductor wafer 50 is subjected to CMP polishing while being supplied to the semiconductor wafer 50. Further, the polishing pad 5b rotates at a predetermined speed in the horizontal direction, for example, when a driving force of a motor (not shown) is transmitted through the spindle 5a.

  Further, as shown in FIG. 3, the processing liquid (polishing liquid or cleaning liquid) supplied from the processing liquid supply unit 7 so as to penetrate the inside of the spindle 5a along the axial direction of the spindle 5a is polished on the polishing surface of the semiconductor wafer 50. A machining fluid supply path 72 is provided for supplying to the substrate. The machining liquid supply path 72 further penetrates through the central portion of the polishing pad 5b attached to the tip of the spindle 5a, and an injection port 72a for injecting the machining liquid is formed at the tip. On the other hand, the end of the machining liquid supply path 72 opposite to the injection port 72a is connected to a machining liquid supply unit 7 described later.

  As shown in FIGS. 2 and 3, the polishing unit moving mechanism 6 includes, for example, a moving base 61, a horizontal movement support member 62 that supports the horizontal movement of the polishing unit 5, and the moving base 61. And a pair of horizontal movement guide members 63 for guiding the movement of the horizontal movement support member 62 in the X axis direction, and a horizontal movement guide member 63 extending in the X axis direction. A ball screw 65 that engages with the support member 62 and is rotationally driven by the electric motor 64, a vertical movement support member 66 that supports the vertical movement of the polishing unit 5, and a Z-axis direction are arranged. , Two pairs (four) of vertical movement guide members 67 for guiding the movement of the vertical movement support member 66 in the Z-axis direction, and the ball screw 6 engaged with the vertical movement support member 66 and rotated by an electric motor 68. Consisting of.

  The polishing unit moving mechanism 6 having such a configuration moves the polishing unit 5 in the X-axis direction by rotating the ball screw 65 and moving the horizontal movement support member 62 in the X-axis direction along the horizontal movement guide member 63. Can be made. Further, the polishing unit moving mechanism 6 moves the polishing unit 5 in the Z-axis direction by rotating the ball screw 69 and moving the vertical movement support member 66 along the vertical movement guide member 67 in the Z-axis direction. Can do.

  For example, as shown in FIG. 4, the processing liquid supply unit 7 includes a processing liquid supply path 72 that supplies a processing liquid (polishing liquid or cleaning liquid) to the polishing unit 50, a polishing liquid storage tank 74 that stores the polishing liquid, A cleaning liquid storage tank 76 for storing a cleaning liquid used for removing contamination on the surface of the semiconductor wafer 50, a processing liquid supply pump 78 for sending the processing liquid to the processing liquid supply path 72, and a polishing liquid for controlling the supply of the polishing liquid A supply valve 742 and a cleaning liquid supply valve 762 for controlling the supply of the cleaning liquid are provided.

  The machining liquid supply unit 7 having such a configuration is configured to supply a plurality of types of machining liquid between the surface to be polished (that is, the back surface of the semiconductor wafer 50) and the polishing pad 5b during the polishing process. . Specifically, for example, an alkaline liquid (slurry) containing abrasive grains as a polishing liquid is stored in the polishing liquid storage tank 74, pure water is stored as a cleaning liquid in the cleaning liquid storage tank 76, and the polishing liquid supply valve 742 is opened and closed. By switching between opening and closing of the cleaning liquid supply valve 762, either the polishing liquid or the cleaning liquid can be selectively supplied.

  In the semiconductor wafer processing apparatus 1 having the above-described configuration, when the turntable 8 rotates and the semiconductor wafer 50 subjected to finish grinding is positioned in the polishing region D, the polishing pad 5b provided in the polishing unit 5 is used. The semiconductor wafer 50 is brought into contact from the upper side of the semiconductor wafer 50 held on the chuck table 9 located in the polishing region D, and a polishing liquid containing free abrasive grains is supplied from a processing liquid supply path 72 inside the polishing pad 5b. 50 finish ground surfaces are chemically mechanically polished (CMP).

  Here, the chuck table 9 and the polishing pad 5b are configured to be rotatable in the horizontal direction (on the XY plane). When the polishing unit 5 is polishing the semiconductor wafer 50, the chuck table 9 and the polishing pad Both 5b rotate in the same direction or in the opposite direction. Further, in order to increase the polishing efficiency, in addition to the above rotation, polishing may be performed while the polishing pad 5b is swung in the horizontal direction (X-axis direction) during the polishing process.

  Next, when the polishing process for polishing the back surface of the semiconductor wafer 50 is completed, the polishing liquid supply valve 744 of the processing liquid supply unit 7 is closed and the cleaning liquid supply valve 764 is opened to supply the polishing liquid containing the free abrasive grains. Switching from pure water to pure water, polishing (so-called water polishing) while supplying pure water. This water polishing is performed for the purpose of removing contamination such as polishing dust adhering to the semiconductor wafer 50.

  By the way, in the step of chemically and mechanically polishing the back surface of the semiconductor wafer 50, the free abrasive grains contained in the polishing liquid enter the irregularities on the surface of the polishing pad 5b, causing the polishing pad 5b to be clogged, or polishing pad 5b. The loose abrasive particles adhering to the surface of the semiconductor wafer 50 may damage the surface of the semiconductor wafer 50 when the next semiconductor wafer 50 is polished. Accordingly, it is necessary to clean the polishing pad 5b. However, if a separate cleaning step for the polishing pad 5b is provided, the throughput decreases as described above. Therefore, in the present embodiment, the water polishing step is performed. At this time, the surface of the polishing pad 5b is cleaned by using the polishing pad cleaning means 40 at the same time.

  For example, as shown in FIG. 3, the polishing pad cleaning means 40 according to the present embodiment is provided near the chuck table 9 within a range in which the polishing unit 5 moves in the X-axis direction (horizontal direction), for example, a cleaning brush. , Provided in the form of a fluid injection nozzle or the like. Hereinafter, the configuration and operation of the polishing pad cleaning means 40 will be described in detail.

  First, the configuration of the polishing pad cleaning means 40 will be described with reference to FIG. 5A and 5B are top views for explaining the configuration and arrangement of the polishing pad cleaning means 40 according to the present embodiment. FIG. 5A is a first installation example, and FIG. 5B is a second installation example. It is shown.

  As shown in FIG. 5, the polishing pad cleaning means 40 is disposed at least in the vicinity of the chuck table 9d located in the polishing region D where the semiconductor wafer 50 is polished. Specifically, for example, as shown in FIG. 5 (a), four polishing pad cleaning means 40a to 40d are arranged in the vicinity of the four chuck tables 9a to 9d arranged on the turntable 8, respectively. It is good also as a structure fixed and installed on the table 8. FIG. In this case, the polishing pad cleaning means 40a to 40d are used when each of the four chuck tables 9a to 9d is located in the polishing region D. On the other hand, when the chuck tables 9a to 9d are located in the other carry-in / carry-out area A, rough grinding area B, and finish grinding area C, the polishing pad cleaning means 40a to 40d are not used.

  Further, as shown in FIG. 5B, one polishing pad cleaning means 40 may be supported by a movable support member 45, and the movable support member 45 may be supported by a fixed support member 46. The right end of the movable support member 45 is connected to the substantially central portion of the fixed support member 46 fixedly installed outside the turntable 8, and the movable support member 45 has the right end as a fulcrum as a fulcrum in FIG. As shown by the arrow of b), it is provided so that rotation is possible. As a result, the polishing pad cleaning means 40 can be retracted to the outside of the turntable 8 when not in use, and only in the vicinity of the chuck table 9d shown in FIG. 5B when the water polishing step is performed. Can be positioned.

  Thus, by providing the polishing pad cleaning means 40 so as to be retractable, the polishing pad cleaning means 40 is brought into contact with the polishing pad cleaning means 40 and the polishing pad 5b or the grinding wheels 3b and 4b during a normal polishing process. Etc. can be prevented.

  As the polishing pad cleaning means 40 having the above-described configuration, for example, a liquid ejecting means for ejecting a liquid such as pure water, or a two-fluid ejected by mixing a liquid such as pure water and a gas such as air. A spraying means, a brush means having a cleaning brush, and the like are conceivable.

  Hereinafter, a method for cleaning the polishing pad 5b using the polishing pad cleaning means 40 will be described in detail with reference to FIGS. FIG. 6 is an explanatory diagram showing a method for cleaning the polishing pad 5b using the polishing pad cleaning means 40A according to the present embodiment. FIG. 7 shows the polishing pad cleaning means 40B according to a modification of the present embodiment. It is explanatory drawing which shows the washing | cleaning method of the used polishing pad 5b.

  FIG. 6 shows an example in which the polishing pad cleaning means 40 is a cleaning water jet nozzle 40A as a liquid jet means. The cleaning water jet nozzle 40A includes cleaning water supply means 42A. In the example shown in FIG. 6, a liquid such as pure water W is sprayed from the cleaning water supply means 42A toward the surface of the polishing pad 5b, for example, and free abrasive grains adhering to the surface of the polishing pad 5b are removed. By removing, the polishing pad 5b is cleaned.

  At this time, the polishing pad cleaning means 40 can be made to act on the entire surface of the polishing pad 5b by swinging the polishing pad 5b in the horizontal direction (X-axis direction). That is, the cleaning water jet nozzle 40A as the polishing pad cleaning means 40 causes at least a distance d from the outer peripheral portion to the center of the polishing pad 5b in the radial direction of the polishing pad 5b by the swinging of the polishing pad 5b in the X axis direction. Relative movement along. Further, since the polishing pad b rotates in the horizontal direction while the polishing pad 5b is positively moved in the X-axis direction, the polishing pad is moved by moving the cleaning water jet nozzle 40A in the radial direction of the polishing pad 5b. The entire surface of 5b can be cleaned.

  Even when the polishing pad cleaning means 40 is a two-fluid injection means, the polishing pad 5b can be cleaned as in the case of the cleaning water injection nozzle 40A.

  FIG. 7 shows an example in which the polishing pad cleaning means 40 is a cleaning brush 40B as a brush means. The cleaning brush 40B includes brush bristles 42B. Instead of spraying the cleaning water onto the polishing pad 5b as in the case of FIG. 6, after bringing the bristles 42B into contact with the surface of the polishing pad 5b, the polishing pad 5b is swung and the cleaning brush 40B is moved to the polishing pad 5b. By moving relative to the radial direction, loose abrasive grains and the like adhering to the surface of the polishing pad 5b can be scraped off. Since the operation of the cleaning brush 40B other than the above is the same as that in the case where the cleaning water jet nozzle 40A is used as the polishing pad cleaning means 40, detailed description thereof is omitted.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above embodiment, the example of the semiconductor wafer 50 has been described as a specific example of the workpiece, but the present invention is not limited to such an example. Workpieces are, for example, various semiconductor substrates, sapphire substrates, glass materials, ceramic materials, metal materials, synthetic resin materials such as plastics, or electronic material substrates for forming magnetic heads, laser diode heads, etc. There may be. Further, the shape of the workpiece may be an arbitrary shape such as a substantially elliptical plate or a substantially rectangular plate in addition to the substantially disk shape.

  In the above embodiment, the workpiece processing apparatus includes the two grinding units 3 and 4, but is not limited to this example, and is configured to include only one or three or more grinding units. You can also

  In the above embodiment, the polishing pad cleaning unit 40 is fixed and the polishing pad 5b is moved to move the polishing pad cleaning unit 40 in the radial direction of the polishing pad 5b. The present invention is not limited to such an example, and the polishing pad cleaning means 40 may be moved.

  In the above embodiment, the polishing pad cleaning means 40 is configured to be retractable, and the polishing pad cleaning means 40 is configured to be rotatable. However, the present invention is not limited to this example. However, the cleaning means supporting members (45, 46) may be moved up and down and left and right.

  The present invention can be applied to a processing apparatus and a processing method, and in particular, can be applied to a processing apparatus including a polishing unit for chemically and mechanically polishing the surface of a workpiece and a processing method using the same.

1 is a perspective view showing an overall configuration of a semiconductor wafer processing apparatus according to a first embodiment of the present invention. It is a perspective view which shows the structure of the grinding | polishing unit which concerns on the same embodiment. It is a side view which shows the structure of the grinding | polishing unit which concerns on the same embodiment. It is explanatory drawing which shows the internal structure of the process liquid supply unit which concerns on the same embodiment. It is a top view for demonstrating the structure and arrangement | positioning of the polishing pad washing | cleaning means based on the embodiment. It is explanatory drawing which shows the cleaning method of the polishing pad using the polishing pad cleaning means which concerns on the embodiment. It is explanatory drawing which shows the cleaning method of the polishing pad using the polishing pad cleaning means which concerns on the modification of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor wafer processing apparatus 3 Rough grinding unit 4 Finish grinding unit 5 Polishing unit 5a Spindle 5b Polishing pad 6 Polishing unit moving mechanism 7 Processing liquid supply unit 8 Turntable 7 Chuck table 9 Processing liquid supply unit 11, 12 Cassette 15 Transfer arm 20 Robot pick 30 Spinner cleaning device 40 Polishing pad cleaning means 40A Cleaning water jet nozzle 40B Cleaning brush 45 Cleaning unit support member 50 Semiconductor wafer 72 Processing liquid supply path

Claims (6)

A chuck table for holding the workpiece;
A turntable provided with a plurality of chuck tables and rotatably provided;
Grinding means for grinding the workpiece held on the chuck table;
A polishing pad having a diameter larger than that of the workpiece; and a processing liquid supply means for selectively supplying a polishing liquid and a cleaning liquid; and the upper side of the workpiece held on the chuck table. Polishing means for polishing the workpiece by contacting with the workpiece;
A polishing pad cleaning means provided on the turntable in the vicinity of each of the plurality of chuck tables disposed on the turntable and cleaning the surface of the polishing pad from below;
With
The polishing means is held by the chuck table and chemically and mechanically polished while supplying a polishing liquid to the processing surface of the workpiece ground by the grinding means ,
The polishing pad cleaning means cleans the surface of the polishing pad when the processing liquid supply means supplies the cleaning liquid while moving relative to the polishing pad in the radial direction of the polishing pad. A processing device characterized by The processing apparatus according to claim 1, wherein the polishing pad cleaning unit relatively moves at least from a center portion to an outer peripheral portion of the polishing pad. The polishing pad cleaning means, characterized in that it is a liquid ejecting means which ejects liquid, machining apparatus according to claim 1 or 2. The polishing pad cleaning means, characterized in that it is a two-fluid injection means for injecting a mixture of liquid and gas, processing apparatus according to claim 1 or 2. The polishing pad cleaning means, characterized in that it is a brush unit, the processing apparatus according to claim 1 or 2. In the processing method using the processing apparatus of any one of Claims 1-5 :
During the polishing step of polishing the workpiece held on the chuck table, the supply of the polishing liquid to the processing surface of the workpiece is stopped, and the cleaning water is supplied to the processing surface. And polishing the surface of the polishing pad by relatively moving the polishing pad cleaning means and the polishing pad in the radial direction.

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