KR20090013407A - Apparatus for grinding wafer - Google Patents

Abstract

A wafer polishing apparatus is provided to prevent defects from being generated in the surface of wafer by preventing the foreign material adheres to the pad of the handler. The handler(90) moves the polished wafer to the corresponding process and has the pad(92) contacted with the wafer. The removing part of a foreign substance(110) removes the foreign material which can stick to the pad. The rotary power part supplies the rotation power to the removing part of a foreign substance. One or more rotating bar is combined with the rotary power part and is rotatable on the central axis of the rotary power part.

Description

Wafer Grinding Equipment {Apparatus for grinding wafer}

The present invention relates to a wafer polishing apparatus, and more particularly, to prevent the occurrence of defects on the surface of the wafer by preventing foreign matter from adhering to the pad of the handler that moves the wafer having been polished to the process. In addition, the present invention relates to a wafer polishing apparatus capable of preventing degradation of performance and efficiency of a DAF (Dicing Attached Film) laminating facility due to a defect generated.

In the wafer fabrication process of forming a semiconductor integrated circuit on the active surface of the wafer, the wafers introduced into the wafer fabrication process in order to suppress damage of the wafer generated during movement or handling between the wafer fabrication apparatuses are substantially a semiconductor package. It is provided in a considerably thicker state than the wafers used in the manufacturing process.

Therefore, after the wafer fabrication process, a process of polishing one surface (rear surface) of the unnecessary wafer is involved before being provided to the semiconductor package fabrication process. Through the polishing of the back surface of the wafer, it is possible to reduce the volume of the semiconductor chip and to ensure good heat dissipation characteristics when packaged and used.

Conventional wafer polishing apparatus for polishing the back of the wafer is an apparatus for polishing the back of the wafer in the order of rough grinding, fine grinding and polishing processes.

This conventional wafer polishing apparatus includes a turntable that is rotatable, four chuck tables provided on the turntable, a wafer cassette for supply and a wafer cassette for storage provided on one side of the turntable. do. A polishing unit that performs a polishing process on the wafer adsorbed on the chuck table is installed on each of the three chuck tables.

As will be described in detail later, four chuck tables are provided for vacuum suction of wafers, and four chuck tables are provided at edge portions along the circumferential direction of the turntable, and rotate together with the turntable at predetermined angles as the turntable rotates.

At this time, the four chuck tables are divided into a standby table on which the wafer waits, a roughing table in which the roughing process is performed, a finishing table in which the finishing process is performed, and a polishing table in which the polishing process is performed.

The polishing unit is installed on the roughing table, the finishing table and the polishing table, except for the waiting table, which is a portion where the wafer is supplied or taken out. Briefly with respect to the polishing unit, the polishing unit is provided with a roughing wheel installed on the top of the roughing table to roughly polish the initial wafer rear surface, and a polishing wheel mounted on the top of the finishing table to precisely polish the back surface of the wafer where the roughing process is completed. And a polisher installed on the polishing table and polishing the back surface of the wafer, in which the finishing process is completed, by chemical mechanical polishing (CMP).

The supply wafer cassette and the storage wafer cassette are provided in proximity to the waiting table. The supply wafer cassette provides a wafer to be subjected to the back polishing process to the waiting table, and the receiving wafer cassette is provided with a wafer on which the back polishing process is completed.

On the other hand, before the polished wafer is stored in the wafer cassette for storage, or after the wafer is stored, that is, the polishing process is completed, the wafer is transferred to a cleaning spinner which is one of the processes and undergoes a cleaning process. In this case, a separate handler transfers the wafer to the cleaning spinner. Such handlers may be used to transfer wafers from the cleaning spinner to the Dicing Attached Film (DAF) laminating facility, as well as between the polishing table and the cleaning spinner.

However, in the conventional wafer polishing apparatus, as the process of transferring the wafer polished by the handler to the process is repeated, foreign matter may accumulate and adhere to the pad of the handler. Since a device for cleaning is not provided, foreign matter stuck to the pad of the handler cannot be removed, and therefore, foreign matter stuck to the pad of the handler may cause defects on the surface of the wafer on which the polishing process is completed.

If the defective wafer is transferred to a DAF (Laminating Attached Film) Laminating Facility afterwards, the wafer may be cracked, which may act as a factor that degrades the facility performance and efficiency. It is urgent to improve the structure for cleaning the pad.

An object of the present invention is to prevent the occurrence of defects on the surface of the wafer by preventing foreign matter from adhering to the pad of the handler for moving the wafer that has been polished to the corresponding process, and furthermore, to the wafer where the defect is generated. Accordingly, the present invention provides a wafer polishing apparatus capable of preventing performance and efficiency of DAF (Dicing Attached Film) laminating equipment from being lowered.

The object is, according to the present invention, a handler having a pad for moving a wafer having been polished to a corresponding process, the pad being substantially in contact with the wafer; And a foreign material removing portion provided in an adjacent region of the handler to remove foreign matters that can be fixed to the pad.

Here, the foreign material removing unit, the rotating power unit for generating a rotating power; At least one rotating bar coupled to the rotating power unit and rotatable about a central axis of the rotating power unit; And at least one oil stone coupled to the rotating bar to remove foreign matters that can be adhered to the pad while in contact with the pad.

The at least one rotating bar may be a pair of rotating bars provided on both sides of the rotating power unit opposite to the center axis of the rotating power unit, wherein the at least one oil stone is the pair of rotating bars Each can be combined into one.

At least one washing water spray nozzle for spraying washing water toward the pad may be further provided at the pair of rotating bars.

The foreign material removing unit, a pair of roller support parts spaced apart from each other; And at least one viscous roller which is rotatably coupled to the roller support and removes the foreign matter adhered to the pad while in rolling contact with the pad.

A tape roller may be further provided between the pair of roller supports to remove foreign substances on the outer surface of the viscous roller by contacting the viscous roller.

The foreign material removing unit may be an etching solution receiving tank provided around the handler and removing the foreign matter which can be fixed to the pad by immersing the pad.

According to the present invention, it is possible to prevent the occurrence of defects on the surface of the wafer by preventing foreign matter from adhering to the pad of the handler which moves the wafer which has been polished to the corresponding process. It is possible to prevent the performance and efficiency of DAF (Dicing Attached Film) laminating equipment from being lowered.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 is a block diagram of a wafer polishing apparatus according to a first embodiment of the present invention.

As shown in this figure, the wafer polishing apparatus according to the present embodiment includes a turntable 10 that is rotatable, a rough polishing portion 30 that undergoes a rough grinding process, and a fine finish. The polishing polishing part 50 which performs a grinding process, and the polishing polishing part 60 which carries out a polishing process are provided.

The rough polishing unit 30, the finishing polishing unit 50, and the polishing polishing unit 60 are each provided along the circumferential direction on the turntable 10, and the backside (one surface or one side or the like) of the wafer W and the process is sequentially performed. Back surface).

Four chuck tables (not shown) are provided on the turntable 10 of the wafer polishing apparatus according to the present embodiment, and three on the top of three chuck tables except the standby table 21 among the four chuck tables. A polishing unit (not shown) is provided.

For reference, the four chuck tables without reference numerals refer to the waiting table 21, the roughing table 31, the finishing table 51, and the polishing table 61, and again with no reference numerals. The three polishing units point to the roughing wheel 32, the finishing wheel 52 and the polisher 62.

At this time, the structures of the four chuck tables are all provided in the same manner, and are provided at equal intervals along the circumferential direction of the turntable 10. Since these four chuck tables are rotated by the turntable 10, substantially four chuck tables serve as the standby table 21, the roughing table 31, the finishing table 51 and the polishing table 61. Perform. In the present embodiment, however, for convenience of description, the chuck table at the moment located in the roughing wheel 32, the finishing wheel 52, and the polisher 62 is respectively roughed table 31, finished table 51, and the like. The polishing table 61 is called.

By this logic, in the present embodiment, the roughing table 31 and the roughing wheel 32 are paired to form the rough polishing part 30, and the finishing table 51 and the finishing wheel 52 are paired. The finishing polishing unit 50 and the polishing table 61 and the polisher 62 are paired to form the polishing polishing unit 60. Each component is demonstrated sequentially.

The turntable 10 is a portion where four chuck tables are supported along the circumferential direction on the upper surface thereof. The turntable 10 may be manufactured in a disk shape. The lower portion of the turntable 10 is coupled to the table shaft 12 to form the center of rotation of the turntable 10. Although not shown in detail, the table shaft 12 is coupled to a bearing for smooth rotation.

As described above, the four chuck tables include a waiting table 21 on which the wafer W waits, a roughing table 31 on which a roughing process proceeds, a finishing table 51 on which a finishing step proceeds, It is divided into a polishing table 61 in which a polishing process is performed.

The waiting table 21, the roughing table 31, the finishing table 51, and the polishing table 61 which are four chuck tables are radially installed in the edge part along the circumferential direction on the turntable 10. As shown in FIG. At this time, the turntable 10 rotates the chuck tables collectively so that any chuck table can be positioned at the position of the neighboring chuck table by rotation, and at the same time, each step of the wafer W polishing process is performed. Allow it to proceed. That is, the four chuck tables serve as the waiting table 21, the roughing table 31, the finishing table 51, and the polishing table 61 by the rotation of the turntable 10.

Looking at the chuck table by position, it is divided into the waiting table 21, the roughing table 31, the finishing table 51, and the polishing table 61 in a clockwise direction, which are 90 degrees to each other at the center of the turntable 10. Can be placed in any position. The turntable 10 rotates by 90 degrees every predetermined time, and the rotation period of the turntable 10 may be set based on the longest running time of the wafer W polishing process.

On the other hand, the supply wafer cassette 15 and the storage wafer cassette 16 are provided on one side of the turntable 10 adjacent to the standby table 21. A conveyer 17 is provided between the standby table 21, the supply wafer cassette 15, and the storage wafer cassette 16. The wafer W to be polished can be transferred from the wafer cassette 15 for supply to the waiting table 21 by the transfer machine 17, and on the contrary, the polished wafer W is stored from the waiting table 21. Can be transferred to a wafer cassette 16 for use. For reference, when the wafer W to be polished is transferred from the wafer cassette 15 for supply to the standby table 21 by the feeder 17, the wafer W is aligned with an alignment means such as a camera (not shown). It may be desirable to transfer to the waiting table 21 after the process of aligning the position of the) is further advanced.

Three polishing units are installed on the roughing table 31, the finishing table 51, and the polishing table 61, except for the waiting table 21. That is, the three polishing units are installed on the roughing table 31 to roughly polish the back surface of the initial wafer W, and are installed on the finishing table 51 to finish the roughing process. Polishing wheel 52 for precisely polishing the back surface of the wafer W, and the back surface of the wafer W, which is installed on the polishing table 61 and completed the finishing process, is polished by chemical mechanical method (CMP). And a polisher 62.

The roughing wheel 32 which forms the rough polishing part 30 together with the roughing table 31 has a particle size of 300 to 350 mesh, for example, 325 mesh, and thus the final wafer W is targeted. Roughly polish the back surface of the wafer (W) to 20 to 30㎛ thicker than the thickness.

The finishing wheel 52 forming the finishing polishing part 50 together with the finishing table 51 has a particle size of 1500 to 2500 mesh, for example 2000 mesh, and precisely polishes the rear surface of the rough polished wafer W to a target thickness. do.

The polisher 62 forming the polishing polishing portion 60 together with the polishing table 61 may also be referred to as a polishing polishing pad. The polisher 62 may be covered with a cloth-like material on its underside. Has a conventional configuration in which a slurry feed is formed. The polisher 62 mirrors the back surface of the finely polished wafer W to the final thickness using the slurry.

On the other hand, before the wafer W, which has been polished through the above-described process, is stored in the wafer cassette 16 for storage or after the wafer W is stored, that is, the wafer W in which the polishing process is completed, a cleaning spinner (not shown). Transferred to a cleaning process.

This is performed by the handler 90 to be described with reference to FIGS. 2 and 3 below. As described above, the handler 90 is used to transfer the polished wafer W to the cleaning spinner, but in addition, the cleaning spinner is equipped with a DAF (Dicing Attached Film) laminating facility. It can also be used to transport them. Therefore, the positional limitation on the handler 90 of the present embodiment will be omitted. That is, the handler 90 of this embodiment is considered to refer to everything used for a particular process.

Since the handler 90 serves to transport the wafer W, which has been substantially polished, the handler W needs to be transported in a clean state. Otherwise, if the foreign matter is buried on the wafer (W), defects are bound to occur on the surface of the wafer (W).

Therefore, the pad 92 of the handler 90 substantially in contact with the wafer W needs to be managed in a clean state, that is, in a state in which foreign matter is not stuck.

However, in the prior art, since there is no means for removing (cleaning) the foreign matter stuck to the pad 92 of the handler 90, the wafer W is transferred to the wafer W in the process of transferring the wafer W as a result. Defect has been generated.

If a wafer with defects (not shown) is subsequently transferred to a DAF (Dicing Attached Film) laminating facility, the wafer may be broken, which may act as a factor that degrades the facility performance and efficiency. It is necessary to manage to prevent foreign matter from adhering to the pad 92 of the handler 90. To this end, in this embodiment, the foreign material removing unit 110 is provided. The foreign material removing unit 110 will be described with reference to FIGS. 2 and 3.

2 and 3 are schematic side and plan views showing the structure of the foreign material removing unit according to the first embodiment of the present invention, respectively.

As shown in these figures, the foreign material removing unit 110 of the present embodiment serves to remove foreign matter that is provided in the adjacent region of the handler 90 and which can be fixed to the pad 92. The foreign material removing unit 110 is largely provided with a rotary power unit 111, a pair of rotary bars 112, and a plurality of oil stones (113, oil stone).

The rotary power unit 111 is a part forming the central body in the foreign material removing unit 110 of the present embodiment, and serves to rotate the pair of rotary bars 112 substantially. Therefore, the rotary power unit 111 may be implemented by a combination of a motor and a gear. For example, a gear such as a sprocket may be mounted on the shaft of the motor, and a pair of rotating bars 112 may be coupled thereto.

The pair of rotating bars 112 are provided on both sides of the rotating power unit 111 with respect to the rotating power unit 111. The pair of rotary bars 112 is rotated around the rotary power unit 111 when the rotary power unit 111 is operated. Of course, since the scope of the present invention is not limited thereto, one rotation bar 112 may be provided, or three or more rotation bars 112 may be provided.

The oil stone 113 serves to remove foreign matter that can be adhered to the pad 92 in a state in which the oil stone 113 is substantially in contact with the pad 92. The oil stone 113 is coupled to the pair of rotating bars 112 one by one. Since the pair of rotary bars 112 rotate about the rotary power unit 111, the oil stone 113 contacts the pad 92 while rotating along the pair of rotary bars 112 and then the pad 92. Remove the foreign matter that can stick to). At this time, the oil stone 113 may be implemented so as to be freely rotatably coupled to the pair of rotary bars 112 individually.

For reference, the oil stone 113 refers to a polishing tool capable of processing from rough grinding to a fairly smooth polishing. Since the pad 92 of the handler 90 is usually made of a silicon material, its surface is easily damaged, and foreign matter is likely to stick. Therefore, in such a case, when the pad 92 is gently polished with the oil stone 113, the surface of the damaged pad 92 may be smoothly recovered and foreign matter may also be removed.

On the other hand, the pair of rotating bar 112 may be further provided with at least one washing water spray nozzle 114 for spraying the washing water toward the pad (92).

When the cleaning water injection nozzle 114 is provided and the pad 92 is gently polished with the oil stone 113 while spraying the cleaning water through the cleaning water injection nozzle 114, the effect of removing foreign matters is further improved. It becomes possible. Of course, since the scope of the present invention is not limited thereto, the washing water injection nozzle 114 is not necessarily provided.

The operation of the wafer polishing apparatus having such a configuration will be described below.

First, the conveyer 17 grips the wafer W from the supply wafer cassette 15 and transfers it to the waiting table 21. In this case, as described above, the process of aligning the position of the wafer W by an alignment means such as a camera (not shown) may be further performed.

When the wafer W is positioned on the standby table 21, the turntable 10 is rotated 90 degrees clockwise with the table axis 12 as the axis. When the wafer W is positioned on the roughing table 31 by the rotation of the turntable 10, the rear surface of the wafer W is roughly polished by the roughing wheel 32.

After the back surface of the wafer W is roughly polished by the roughing wheel 32, the turntable 10 is rotated 90 degrees again, so that the wafer W is positioned on the finishing table 51 and then to the finishing wheel 52. As a result, the back surface of the wafer W is polished. Then, after the polishing process is performed by the polisher 62 by the rotation of the turntable 10 by 90 degrees, the wafer W, which has been polished, is again placed on the standby table 21.

On the other hand, the wafer W positioned on the waiting table 21 is finally transferred to the wafer cassette 16 for storage through the conveyor 17, and the wafer W thus polished is stored in the wafer cassette 16 for storage. The wafer W may be transferred to a cleaning spinner (not shown) before undergoing the storage process or after being stored, that is, the polishing process is completed.

At this time, the polished wafer W is attracted to the pad 92 of the handler 90 and transferred to the cleaning spinner.

However, when this process, that is, the process of repeatedly transferring the polished wafer W to the cleaning spinner while the handler 90 is repeatedly performed, there is a fear that foreign matters may be fixed to the pad 92 of the handler 90. When it is determined that the foreign matter is fixed, the foreign matter that can be fixed to the pad 92 may be removed through the foreign material removing unit 110 of the present embodiment.

Looking at the operation of removing the foreign matter briefly, first, the rotary power unit 111 is operated to rotate a pair of rotating bar 112. When the pair of rotating bars 112 rotate, the oil stone 113 coupled thereto contacts the pad 92 to smoothly polish the pad 92 to remove foreign substances. At this time, if the cleaning water jetting nozzle 114 is provided in the debris removing unit 110, the pad 92 may be polished with the oil stone 113 while spraying the cleaning water through the cleaning water jetting nozzle 114. As a result, the effect of removing foreign matter can be doubled.

As described above, according to this embodiment, the defect is prevented from sticking to the surface of the wafer W by preventing foreign matter from adhering to the pad 92 of the handler 90 which moves the wafer W on which the polishing process is completed to the process. It is possible to prevent the occurrence of the defect, and furthermore, it is possible to prevent the performance and the efficiency of the DAF (Dicing Attached Film) laminating facility due to the defect W generated.

4 is a schematic side view showing the structure of the foreign material removing unit according to the second embodiment of the present invention.

Unlike the above-described embodiment, the foreign material removing part 210 of the present embodiment is rotatably coupled to the pair of roller support parts 211 and the roller support parts 211 which are disposed to be spaced apart from each other, and the handler 90 And at least one viscous roller 212 for removing foreign matter adhered to the pad 92 while rollingly contacting the pad 92.

A tape roller 213 may be further provided between the pair of roller support portions 211 to contact the viscous roller 212 to collect and remove foreign substances on the outer surface of the viscous roller 212.

Briefly looking at the operation of removing the foreign matter by this configuration, first, the pad 92 of the handler 90 is moved in the direction of Fig. 4 (a), and at the same time the viscous roller 212 is rotated.

Then, the surface of the pad 92 is in contact with the rotating viscous roller 212, the foreign matter which can be adhered to the surface of the pad 92 by this operation is transferred to the viscous roller 212 to the surface of the pad 92 Sticky foreign matter is removed. The foreign matter transferred to the viscous roller 212 can be recovered toward the tape roller 213 which again rotates in contact with the viscous roller 212 and its outer surface.

Even when the foreign material removing unit 210 as in the present embodiment is used, foreign matter is prevented from adhering to the pad 92 of the handler 90 which moves the wafer W having been polished to the process, thereby preventing the foreign matter from sticking. It is possible to prevent the occurrence of defects on the surface, and furthermore, to prevent the deterioration of the performance and efficiency of the DAF (Dicing Attached Film) laminating equipment due to the wafer W having the defects. It is enough to achieve.

5 is a structural diagram of a foreign material removing unit according to a third embodiment of the present invention.

Unlike the foreign material removing unit 110 and 210 of the above-described embodiments, the foreign material removing unit 310 of the present embodiment is provided around the handler 90 and the pad 92 is immersed to remove the foreign matter that can be fixed to the pad 92. It is applied as the etching liquid storage tank 310 to be.

That is, the handler 90 is lowered in the direction of FIG. 5B so that the pad 92 is immersed in the etching solution of the etching solution receiving tank 310 and foreign matter is removed by the chemical reaction of the etching solution. . 5, even if configured, there is no problem to achieve the effect of this embodiment.

However, in order to apply the foreign matter removing unit 310 to the etching solution container 310 as shown in FIG. 5, and to allow the pad 92 of the handler 90 to be immersed in the etching solution container 310, the handler 90 is illustrated in FIG. 5. The structure which raises and lowers in 5 (b) direction is calculated | required. However, such a configuration can be easily implemented by pneumatic, hydraulic and pneumatic cylinders or actuators, or a combination of a motor and a ball screw, so a detailed description thereof will be omitted.

As described above, the present invention is not limited to the described embodiments, and various modifications and changes can be made without departing from the spirit and scope of the present invention, which will be apparent to those skilled in the art. Therefore, such modifications or variations will have to be belong to the claims of the present invention.

1 is a block diagram of a wafer polishing apparatus according to a first embodiment of the present invention.

2 and 3 are schematic side and plan views showing the structure of the foreign material removing unit according to the first embodiment of the present invention, respectively.

4 is a schematic side view showing the structure of the foreign material removing unit according to the second embodiment of the present invention.

5 is a structural diagram of a foreign material removing unit according to a third embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

10: turntable 12: table axis

14 cross roller bearing 15 wafer cassette for supply

16: storage wafer cassette 17: transfer machine

21: waiting table 30: rough grinding

31: roughing table 32: roughing wheel

50: finishing polishing part 51: finishing table

52: finishing wheel 60: polishing polishing unit

61: polishing table 62: polisher

90: handler 92: pad

110,210,310: Foreign body removal part

Claims (7)

A handler for moving a polished wafer to a corresponding process, the handler having a pad substantially in contact with the wafer; And And a foreign material removing unit provided in an adjacent region of the handler to remove the foreign matter adhered to the pad. The method of claim 1, The foreign material removing unit, A rotating power unit for generating rotating power; At least one rotating bar coupled to the rotating power unit and rotatable about a central axis of the rotating power unit; And And at least one oil stone coupled to the rotating bar to remove the foreign matter adhered to the pad in contact with the pad. The method of claim 2, The at least one rotation bar is a pair of rotation bars are provided in pairs on both sides of the rotation power unit facing the center axis of the rotation power unit, And said at least one oil stone is coupled to each of said pair of rotating bars one by one. The method of claim 3, And at least one washing water spray nozzle for spraying the washing water toward the pad. The method of claim 1, The foreign material removing unit, A pair of roller supports spaced apart from each other; And And at least one viscous roller which is rotatably coupled to the roller support and removes foreign matter adhered to the pad while being in rolling contact with the pad. The method of claim 5, Wafer polishing apparatus, characterized in that the tape roller (tape roller) for removing the foreign matter on the outer surface of the viscous roller in contact with the viscous roller is further provided between the pair of roller support. The method of claim 1, The foreign material removing unit is a wafer polishing apparatus, characterized in that the etching solution container is provided in the periphery of the handler and the pad is immersed to remove the foreign matter that can be fixed to the pad.

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