JP3883256B2 - Polishing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polishing apparatus, and more particularly to a polishing apparatus that polishes a material to be polished such as a semiconductor wafer to a flat and mirror surface.
[0002]
[Prior art]
In recent years, as semiconductor devices are highly integrated, circuit wiring is becoming finer and the distance between wirings is becoming narrower. Along with this, the depth of focus becomes shallow when circuit formation is performed by optical lithography or the like, so that a higher flatness of the imaging surface of the stepper is required. Chemical mechanical polishing as a means to flatten the surface of a semiconductor wafer by pressing the wafer held by a carrier against the polishing cloth while supplying a polishing liquid containing abrasive grains to the polishing cloth affixed on a rotating turntable (CMP) is performed.
[0003]
As such a polishing apparatus, a polishing apparatus having a polishing table that periodically moves in a plane and a gripping member that presses a polishing surface of a material to be polished against the polishing table is used. Further, in such a polishing unit, a storage device for storing the material to be polished, a cleaning device for cleaning the material to be polished in the polishing device, and an inversion provided adjacent to the storage portion A polishing apparatus to which an apparatus and a conveying apparatus for transferring a material to be polished between these units or apparatuses are added is used.
[0004]
For example, as shown in FIG. 4, the storage units 100 a and 100 b for storing the material to be polished, at least two polishing units 106 a and 106 b each having a turntable 102 and a top ring 104, Cleaning devices 108a to 108d for cleaning and drying the material polished in 106b, a conveying device 110 for transferring the material to be polished between these devices, and reversing machines 112a and 112b for reversing the material to be polished It has. Each unit is disposed in an air-conditioning accommodating space in a rectangular parallelepiped shape constructed of a frame, for example, considering the processing flow as a whole and the conveyance of the material to be polished.
[0005]
Since this polishing apparatus has two polishing units, when performing polishing work in multiple stages by changing the polishing liquid in the production of compound semiconductors, etc., contamination by the previous polishing liquid is prevented, and the quality and yield are reduced. Further, in the case of one-stage polishing, it can be used in parallel with each polishing unit to increase the throughput.
[0006]
[Problems to be solved by the invention]
However, in the above polishing apparatuses described above, since various apparatuses for performing each processing step are densely arranged in the same accommodation space, for example, splashes of polishing liquid emitted from the polishing units 106a and 106b are washed. There is a possibility of contaminating the cleaned wafer in the apparatus 108d. Therefore, it is conceivable to prevent contamination by partitioning each processing unit with a partition wall according to the required cleanliness. However, in that case, there is a problem that it becomes more difficult for a person to access each device than in the past, and maintenance such as inspection and repair becomes difficult.
[0007]
Accordingly, an object of the present invention is to provide a polishing apparatus capable of easily maintaining each apparatus while preventing cross contamination between apparatuses.
[0008]
[Means for Solving the Problems]
The invention according to claim 1, in the polishing apparatus having a plurality of apparatus for performing a plurality of processes including chemical mechanical Migaku Ken of the polishing surface of the abrasive, a plurality of room interior space of the polishing apparatus comprising a wall that divides a closable door provided in a part of the wall of each room, and a guide rail for retracting a predetermined device external to the polishing apparatus of the plurality of devices The predetermined device travels on the guide rail and is retracted outside the polishing device, so that maintenance of other devices can be performed from the place where the predetermined device was originally located. Is a polishing apparatus. As a result, when performing maintenance on each part of the polishing apparatus, the doors provided on part of the wall such as the outer wall or partition wall that divides the room containing each part are opened, so that those parts can be directly accessed. Can be accessed.
[0009]
Further, a space is formed there place of this device by retracting outside of the room by the guide rails a predetermined device, the maintenance required by goes here human.
[0010]
According to a second aspect of the present invention, the predetermined device is provided between a storage device for storing a material to be polished and a polishing device for chemically and mechanically polishing a polishing surface of the material to be polished. The polishing apparatus according to claim 1, wherein the polishing apparatus is a temporary storage chamber for temporarily storing a workpiece to be transferred to and from the polishing apparatus. The temporary storage room is located in a transfer path for transferring the material to be polished between the rooms, and a passage for maintenance to each room is configured by retracting the temporary storage room.
[0011]
According to a third aspect of the invention, since the floor along the guide rail is a polishing apparatus according to claim 1, characterized in that coated with the floorboard, wiring passage for maintenance, piping, driving mechanism, etc. Is not exposed, it is easy for people to pass through, and it is not damaged by catching wiring or the like during the passage.
[0012]
Invention according to claim 4, polishing apparatus according to claim 1, wherein a plurality of cleaning portions there, each one or more of the cleaning section on both sides of the predetermined device is arranged such that It is.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a polishing apparatus according to the present invention will be described below with reference to FIGS. The device is entirely of floor space forming the rectangular end side single 2 groups side polishing apparatus 10a, 10b are arranged, the wafer accommodating cassette 12a at the other end, 12b and placed to Carlo over de -An unload unit 14 is arranged.
[0014]
Two-rail running rails 16a and 16b are laid from the loading / unloading unit 14 along the longitudinal direction of the apparatus with the transfer gate 18 therebetween, and the transfer robots 20a and 20b run on the rails 16a and 16b. Arranged to be possible. At the front end side of the traveling rails 16a and 16b, a buffing device 22 and a tool washing tank 23a for dressing the buffing tool are provided. Next to the traveling rails 16a and 16b, two reversing machines 24a and 24b are provided. And three washing machines 26a, 26b, and 26c are arranged.
[0015]
The two polishing apparatuses 10a and 10b include a turntable 28 with a polishing cloth affixed to the upper surface, a top ring 30 that holds the wafer by vacuum suction and presses it against the turntable 28, and a dressing apparatus 32 that sharpens the polishing cloth. And means for supplying a polishing liquid containing water and abrasive grains to the turntable 28 and the dressing device 32, and the wafer is placed between the top ring 30 at a position facing each transfer line. A pusher 34 for giving and receiving is installed. The top ring 30 can be turned in a horizontal plane, and the pusher 34 can be moved up and down.
[0016]
The buffing device 22 further finishes or cleans and polishes the wafer polished by the polishing devices 10a and 10b. The buffing device 22 is configured as a translation table (buffing tool) with a buff attached thereto. , A top ring (gripping device) 22a for gripping the wafer from the pusher and pressing the wafer against the buffing tool, and a dressing tool (dressing device) 23 for sharpening the buffing tool. ing. FIG. 1 shows a state in which the top ring 22a is on the buffing tool and the dressing tool 23 is on the cleaning tank 23a.
[0017]
When the wafer is polished by the buffing apparatus, the top ring 22a and the dressing tool 23 are moved from the state of FIG. 1, the top ring 22a is positioned on the pusher 36, and the dressing tool 23 is positioned on the buffing tool . While regenerating the buffing tool, the wafer on the pusher 36 is held by the top ring 22a, the top ring 22a and the dressing tool 23 are moved again to the position of FIG. 1, and the wafer is polished by the top ring 22a and the buffing tool. Meanwhile, the dressing tool 23 is cleaned by the cleaning tank 23a . Such a configuration of the buffing apparatus 22 saves space because the polishing tool has a smaller diameter than the case of using a turntable that rotates.
[0018]
The types of the cleaning machines 26a, 26b, and 26c are selected according to the purpose. For example, a pencil type with a sponge at the tip or a roller type with a sponge is used to clean one side or both sides of the wafer. Alternatively, the last-stage cleaning machine 26c is of a type that spins a wafer to dehydrate and dry it.
[0019]
The transfer robots 20a and 20b are provided with joint arms that are refracted in a horizontal plane at the upper part of a carriage that runs on rails 16a and 16b, for example, and two gripping units (hands) at the tips of the upper and lower arms. have. The upper hand of the first robot 20a is a dry hand 38a for handling a wafer before polishing and after drying, the lower hand is a wet hand 38b for handling a wafer before drying, and the upper side of the second robot 20b is A clean hand 38c for handling clean wafers, and a dirty hand 38d for handling wafers in the polishing process on the lower side. The four types of hands 38a to 38d can move up and down, and can enter an upper stage or a lower stage of a transfer gate 18 described later.
[0020]
In this embodiment, the reversing devices 24a and 24b are necessary in relation to the cassette storing method and the robot gripping mechanism. However, the reversing devices 24a and 24b are necessary when the wafer polishing surface is always transferred downward. is not. In addition, it is not necessary in the case of a structure in which the robots 20a and 20b have an inversion function. In this embodiment, the two reversing machines 24a and 24b are selectively used for the one 24a that handles a dry wafer before polishing and the one 24b that handles a wet wafer after polishing.
[0021]
In this polishing apparatus, a rectangular parallelepiped housing space 42 surrounded by an outer wall 40 is partitioned by a partition wall 44 to form a plurality of rooms R _{1 to} R ₅ . That is, loading and unloading unit 14, the first transfer robot 20a, and its inverting unit 24a disposed on the side and two cleaning device 26b, the space is the first room _{R 1} becomes comprising 26c, the second the transfer robot 20b and a space including a reversing machine 24b and the cleaning device 26a disposed on one side of this second chamber R ₂ becomes, the space including the buffing apparatus 22 third chamber R _3, each of the polishing apparatus 10a , 10b are the fourth and fifth rooms R ₄ , R ₅ . In this example, the space R ₆ adjacent to the loading and unloading unit 14 is disposed a control device (not shown), also the space R ₇ adjacent thereto is opened to put a human for maintenance Yes. The partition between the rooms R ₅ and R ₇ and the partition between the rooms R ₁ and R ₇ are for preventing the air in the rooms R ₁ and R ₅ from exiting to the room R ₇ . Since the room R ₇ communicates with the outside of the polishing apparatus (clean room), it is necessary to keep the cleanness high. The following points are important in partitioning each room with the partition wall 44. That is, the rooms R ₄ and R ₅ including the polishing apparatus are most contaminated in the polishing apparatus, and it is important to isolate the rooms R ₄ and R _{5 from the} room R ₁ that requires high cleanliness.
[0022]
A transfer gate 18 is provided between the first room R ₁ and the second room R ₂ for temporarily placing the material to be polished between the rooms. This is a plastic box where wafers are passed between these rooms. As shown in FIG. 3, the interior is partitioned into upper and lower temporary storage chambers 18a and 18b, and a wafer in a dry state in the upper stage and a wafer in a wet state in the lower stage are delivered. Although not shown, a shutter (not shown) is provided at a position facing the pushers 34 and 36 also on the partition between the second room R ₂ and the third and fourth rooms R ₃ and R _4. It has been.
[0023]
Shutters 50a ₁ , 50a ₂ , 50b ₁ , 50b _{2 that} are individually opened and closed for the upper and lower temporary storage chambers 18a, 18b are provided at positions facing the first room R ₁ and the second room R _2. Yes. Further, holes H ₁ , H ₂ , and H ₃ are formed in the upper and lower and intermediate partition walls of the transfer gate 18, respectively, and an air supply duct 19 a is supplied to the holes H ₁ and H ₃ so that clean air flows in sequence. And an exhaust duct 19b is provided. Further, a nozzle for injecting water into the wafer is provided in the temporary storage chamber 18b on the lower stage side. Thus, by blowing air from the upper stage toward the lower stage, it is possible to prevent the particles in the temporary storage chambers 18a and 18b from scattering, and the temporary storage chambers 18a and 18b mutually contaminate the inside. I won't meet you. Further, by using the lower temporary storage chamber 18b for transferring a wet wafer, contamination of the upper temporary storage chamber 18a can be prevented.
[0024]
The reason why the inside of the transfer gate 18 is partitioned into the upper and lower temporary storage chambers 18a and 18b in this way is to increase the throughput first. That is, if there is only one stage, when an unpolished wafer is stored in the transfer gate 18, a polished wafer cannot be put into the transfer gate 18 during that time, and an unpolished wafer leaves the transfer gate for a polished wafer. It is necessary to wait in the cleaning machine 26a until the wafer does not flow smoothly. That is, a waiting time occurs. The same thing happens for unpolished wafers when a polished wafer is stored in a transfer gate. If there are two upper and lower stages, the above-described waiting time does not occur, so the throughput increases. That is, the operation of sending an unpolished wafer from room R ₁ to R ₂ and the operation of sending a polished wafer from R ₂ to R ₁ can be performed simultaneously by four hands.
[0025]
Second, as described above, the two temporary storage chambers 18a and 18b are selectively used for transporting a clean material to be polished and processing a non-clean material to be polished, so that the material to be polished becomes contaminated via the transfer gate 18. This is to prevent this. In this example, a wet wafer is placed in the lower stage, and water is applied to the wafer from a nozzle provided in the box so that particles do not adhere to the wafer. Therefore, the cradle for the wafer in the box is wet and dirty with particles. On the other hand, the upper stage is used exclusively for dry wafers and is not wetted like the lower stage, so the upper stage cradle is not wet. Therefore, the wafer may be temporarily returned to the load / unload unit 14 when a trouble occurs in the apparatus when the wafer is in the upper stage, but the wafer is not contaminated by the upper stage cradle, so the wafer is cleaned. It can be returned to the load / unload unit 14 as it is. If the unpolished wafer is contaminated and returns to the load side, the contaminants (particles) are dried and fixed on the wafer, which becomes a source of scratches on the wafer surface during polishing.
[0026]
Further, in this embodiment, the shutter _{50a 1, 50a 2, 50b 1} , 50b 2 of the transfer gate 18 and below each tentative incubation cabinet 18a, provided for each of the two outlets of 18b the room R _1, R _This is to prevent the air from flowing between the transport gate 18 and the transport gate 18 so as not to contaminate the clean space particularly on the R ₁ side. That is, when the dry hand 38a is put dry wafer upper part only shutter 50a ₁ is opened, further opens the shutter 50b ₁ by closing the shutter 50a _1, take out the dry wafer from the upper to the room R ₂ by dirty hands 38d.
[0027]
Similarly, clean hand 38c is when put the washed wet wafer in the lower part in the cleaning apparatus 26a, opens the shutter 50b _2, to open only shutter 50a ₂ when taken wet hand 38b is a wet wafer from the lower . Since only the necessary shutters are opened in this way, air circulation in the rooms R ₁ and R ₂ and the transfer gate 18 is prevented. Note that the wafer is placed in the temporary storage chamber of the transfer gate, the shutter on the inserted side is closed, and the other shutter is opened, taking a short time to supply clean air from H ₁ , By substituting the air, cross contamination from the transfer gate can be more completely prevented. The room R ₁ is kept clean, whereby the dry hand 38a, the unpolished dry wafer, and the dry wafer that has been polished, washed and dried can be kept clean. The dry hand 38a needs to be kept clean in order to transport the dried dry wafer.
[0028]
This polishing apparatus is provided with a door that can be opened and closed on a part of a wall that partitions each room in order to facilitate maintenance of various apparatuses accommodated in each room. That is, in the first room R ₁ , a pair of foldable folding doors 60 a are provided on the outer wall 40 of the housing space 42 on the side of the cleaning devices 26 b and 26 c, and a partition wall with the maintenance space R ₇ is provided. 44 is also provided with a rotatable door 60b that is rotatable via a hinge. In the second room R ₂ , a pair of foldable doors 60 c that are foldable are provided on the outer wall 40 of the housing space 42 on the cleaning device 26 a side. In the third room R ₃ , a pair of foldable doors 60 d that are foldable are provided on the end side outer wall 40 of the accommodation space 42. In the fourth room R ₄ , a pair of foldable doors 60 e that are foldable are provided on the end side outer wall 40 of the accommodation space 42. In the fifth room R ₅ , a folding door 60 f that can be folded on a partition wall 44 with a maintenance space R ₇ and a rotatable door 60 g that is rotatable via a hinge are provided.
[0029]
The transfer gate 18 is configured so that it can move in the accommodation space 42 along the space R ₈ provided between the first room R ₁ and the second room R ₂ , or can be retracted outside. A pair of rails 64 are laid on the floor surface of the space R ₈ , and the transfer gate 18 can travel on the rails 64. Further, the inlet portion of the space R _8, rotatable rotary door 66 is provided through a hinge.
[0030]
The flow of the wafer when polishing the wafer in the polishing apparatus having such a configuration will be described. The wafers are taken out from the cassettes 12a and 12b containing a plurality of wafers placed on the load / unload unit 14 by the dry hand 38a of the first robot 20a, reversed by the first reversing machine 24a, and then transferred. The shutter 50a _{1 of the} gate 18 is opened and placed again on the upper stage by the dry hand 38a. Then, the wafer is taken out dirty hand 38d of the second robot 20b opens the other of the shutter 50b ₁ of the transfer gate 18 is placed on the pusher 34 of the polishing apparatus 10a or 10b to open the shutter of the partition wall.
[0031]
Hereinafter, in the case of parallel processing, the wafer flows in the order of polishing apparatuses 10a and 10b → buff polishing apparatus 22 → reversing machine 24b → cleaning apparatus 26a. In the case of series processing, the first polishing apparatus 10a → cleaning apparatus 26a. → The second polishing apparatus 10b → the buff polishing apparatus 22 → the reversing machine 24b → the cleaning apparatus 26a. The conveyance between the apparatuses so far is performed by the dirty hand 38d.
Next, a relatively clean and and wet wafer after the first cleaning with the cleaning device 26a, is taken out at a clean hand 38c of the second robot 20b, the lower transfer gate 18 opens the shutter 50b ₂ Place, close the shutter 50b _2. Since the clean hand 38c is used only for transferring the polished wet wafer from the cleaning device 26a to the transfer gate 18, the clean hand 38c can be kept clean, and the clean hand 38c does not contaminate the wafer. .
[0032]
In this embodiment, two polishing apparatuses 10 a and 10 b are provided for one buff polishing apparatus 22. This is because the polishing time in the buffing device 22 is shorter than that in the polishing devices 10a and 10b. In the conventional apparatus, when only one primary polishing apparatus is provided, the secondary polishing apparatus (buff polishing apparatus 22) was not polished until the primary polishing of the next wafer was completed. Since the apparatus has two primary polishing apparatuses 10a and 10b, the primary polishing of the wafer is performed in parallel, and the buffing apparatus 22 for performing the secondary polishing is not allowed to play, thereby increasing the polishing throughput. Can do.
[0033]
Next, the shutter 50a ₂ of the transfer gate 18 is opened, the wafer is taken out by the wet hand 38b of the first robot 20a, and sequentially sent to the second cleaning device 26b and the third cleaning device 26c for cleaning and drying. Do. The wafer dried by the third cleaning device 26c is taken out by the dry hand 38a of the first robot 20a and returned to the cassettes 12a and 12b of the load / unload unit 14.
[0034]
Next, operations for performing maintenance of the polishing apparatus will be described. As described above, the doors 60a to 60g are provided at locations where maintenance is required in each room, and access is possible by opening the doors. For example, when performing maintenance of the third chamber buffing apparatus accommodated in the R ₃ 22 and dressing apparatus 23, by opening a door 60d provided on the outer wall 40 of the housing space 42 that partitions the room R _3, also , when performing maintenance of the polishing apparatus 10a accommodated in the fifth room R _5, the door 60f provided in the partition wall 44 of the space R ₇ for maintenance by opening 60 g, to do this easily and quickly Can do. This door, especially since is also provided at a position close to the inner side of the just not polishing device 10a outside (back door 60f space R _7), can be easily performed inspection and repair of the inner portion.
[0035]
Furthermore, when inspecting and repairing the devices and parts inside, the door 66 is opened, and the door 60b is opened after the transfer gate 18 is moved in the accommodating space 42 or retracted outside, A person enters the place where the transfer gate 18 was originally located, and from here, necessary maintenance for the transfer robot 20b is performed. When the transfer gate 18 is retracted outside the polishing apparatus, the floor surface of the space R ₈ is provided with a floor cover (floor board) 62a that covers the wiring and the transfer gate, and a person can walk on it. It is possible to prevent stepping on or hanging on rails, wiring, etc., and to perform smooth and safe work. Before moving the transfer gate 18, the airflow ducts 19a, 19b are removed.
[0036]
When the transfer gate is retracted in this way, as shown by the hatched lines in FIG. 1, a person's hand or person reaches the position facing the pusher 34 of the polishing apparatus 10a, 10b from the external space, so a relatively complicated part Inspection and repair are easier. Note that the floor lids (floor plates) 62b and 62c are extended halfway along the travel route of the transfer robots 20a and 20b, and cover the ball screws that drive the transfer robots 20a and 20b. In addition, it is possible to prevent the ball screw from being stepped on.
[0037]
In this embodiment, the robots 20a and 20b are each provided with two hands 38a to 38d, and a case where a cleaned wafer, another wafer, and a wet wafer in a dry state are handled separately is used. As a result, there is no contamination through each hand. Furthermore, since the space in the transfer gate 18 is divided into the upper and lower temporary storage chambers 18a and 18b, there is no contamination through the transfer gate 18.
[0038]
The embodiment of the present invention is not limited to the above, and the configuration, number, type, or arrangement in each device is arbitrary. For example, in the case where series or parallel processing is not performed, only one polishing apparatus is sufficient, and accessory equipment may be small. The presence / absence, arrangement, number, type, presence / absence of pushers 34, 36, and the like of the reversing machine are also arbitrary. For example, the transfer robots 20a, 20b may be stationary instead of traveling on rails. In the above embodiment, the first room R ₁ includes the load / unload unit 14. However, the load / unload unit 14 requiring particularly high cleanliness may be covered with a partition wall to be a separate room. Further, a shutter for transferring a wafer between the load / unload unit 14 and the robot 20a may be provided on the partition wall. Thereby, mutual contamination between the loading / unloading unit 14 and, for example, the cleaning devices 26b and 26c can be prevented.
[0039]
【The invention's effect】
As described above, according to the present invention, the internal space is divided into a plurality of rooms to prevent cross-contamination between apparatuses, and a door is provided on a part of the wall of each room, and this is opened during maintenance. As a result, each apparatus can be directly accessed, so that maintenance can be easily performed. Further, by providing a guide rail for moving the device in the room or withdrawing to the outside, the device can be moved by moving the predetermined device facing the door in the room with the guide rail or withdrawing the device to the outside. It is possible to form a space in the place where there is a gap and facilitate maintenance inside the apparatus.
[Brief description of the drawings]
FIG. 1 is a plan view showing a polishing apparatus according to the present invention.
FIG. 2 is a plan view schematically showing the polishing apparatus of FIG.
3 is a perspective view showing a transfer gate of the polishing apparatus of FIG. 1. FIG.
FIG. 4 is a plan view schematically showing a conventional polishing apparatus.
[Explanation of symbols]
10a, 10b Polishing device 14 Load / unload unit 18 Transfer gates 18a, 18b Temporary storage chambers 20a, 20b Robot (transfer device)
23 dressing apparatus 24a, 24b reversing machine 26a, 26b, 26c cleaning device 22 buffing apparatus 60a, 60b, 60c, 60d, 60e, 60f, 60g doors 62a, 62b, 62c floor 64 rail R ₁ to R ₈ room

Claims (4)

In the polishing apparatus having a plurality of apparatus for performing a plurality of processes including chemical mechanical Migaku Ken of the polished surface of the object to be polished,
A wall that divides the internal space of the polishing apparatus into a plurality of rooms ;
A door that can be opened and closed on a part of the wall of each room ;
A guide rail for retracting a predetermined device of the plurality of devices outside the polishing device;
The predetermined device is caused to travel on the guide rail and retract outside the polishing device, so that maintenance of other devices can be performed from the place where the predetermined device was originally located. Polishing device. The predetermined device is provided between a storage device for storing a material to be polished and a polishing device for chemically and mechanically polishing a polishing surface of the material to be polished, and is transferred between the storage device and the polishing device. The polishing apparatus according to claim 1, wherein the polishing apparatus is a temporary storage chamber for temporarily storing a material to be polished.   The polishing apparatus according to claim 1, wherein a floor surface along the guide rail is covered with a floor board. There are multiple cleaning portions, polishing apparatus according to claim 1, characterized in that each one or more of the cleaning section on both sides of the predetermined device is arranged so there.

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