JP2000210864A - Plane polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a two steps of polishing at a high speed as easy as posible by a plane polishing device for general purpose. SOLUTION: This device is provided with a transfer station 61, four polishing stations 53 set to surround the transfer station 61, four wafer heads 52 moving independently respectively, and washing stations 56 provided responding to the wafer heads 52 respectively. At the transfer station 61, the wafer heads 52 change to ride a wafer 50, each polishing station 53 has a rotary platen respectively, and the wafer heads 52 adsorb and hold the wafer 50 at their lower surface, so as to freely move vertically, and at the same time, they can access to the adjacent two positions in the polishing stations 53, the transfer station 61, and the washing stations 56. They are arranged in order, so that the adjacent wafer heads 52 have one position in two places of polishing stations 52 where the adjacent wafer heads 52 can be accessible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar polishing apparatus such as a chemical mechanical polishing and a mechanical polishing of a plate-like material such as a semiconductor wafer by continuous processing or batch processing.

[0002]

2. Description of the Related Art An integrated circuit is typically fabricated by depositing and patterning a conductive film layer, a semiconductor film layer, an insulating film layer, and the like to form a wafer (most commonly, a semiconductor wafer). Formed on top. When the deposition layer is continuously deposited and etched, a three-dimensional shape with many irregularities gradually appears on the uppermost surface of the wafer, that is, the exposed surface of the uppermost layer. This is the height of the top membrane layer,
That is, the distance between the uppermost surface of these layers and the surface of the wafer is the largest at the place where the etching is the least, and the smallest at the place where the etching is the most.

[0003] Such surface irregularities pose a problem for integrated circuit manufacturers. The etching step is typically performed by disposing a resist layer on the exposed surface of the wafer and then selectively removing a portion of the resist to provide an etching pattern on the layer. If the layer is not flat, focusing in photolithography for patterning the resist layer becomes difficult. Therefore, there is a need to planarize the wafer surface and restore the planarity of the layer surface for lithography.

[0004] Chemical mechanical polishing (CMP)
Is one way to do that. In this flattening method,
Typically, it is necessary to place the wafer on the wafer head such that the surface of the wafer to be polished is exposed. The wafer supported by the head is placed against a rotating polishing pad. The head holding the wafer may also be rotated to provide additional movement between the wafer and the polishing pad surface. In addition, a polishing slurry (typically having an abrasive and at least one chemically reactive agent, which are selected to facilitate polishing of the top film layer of the wafer) is provided to the pad. The configuration of the slurry is selected according to the material to be polished, such as an oxide layer.

[0005] The characteristics of the polishing pad are similarly selected,
Specific slurry characteristics and other polishing parameters can provide specific polishing characteristics. Other polishing parameters, such as the relative speed of the wafer and pad and the force pressing the wafer against the pad, affect the polishing rate, finish, and flatness. The actual combination of polishing pads, slurries, and other parameters selected for a given material depends on the polishing rate, which determines a significant portion of the wafer throughput in the equipment, and the desired finish on the wafer surface. Decided based on compromise.

Japanese Patent Application Laid-Open No. 9-174420 proposes an apparatus for increasing the throughput and responding to various polishing conditions. FIG. 5 is an exploded perspective view showing the outline thereof (refer to the official gazette for details).

[0007] This polishing apparatus comprises a lower machine base 1.
, On which the table top 2 and a series of polishing stations 3a, 3b and 3c are mounted. As shown, a fence 4 surrounds the tabletop 2 and contains liquids and slurries that are scattered and drains through a drain (not shown) on the tabletop.

The polishing stations 3a, 3b and 3
c each has a rotating platen 6 with a polishing pad 5 disposed thereon and further has an associated pad conditioner device 7a, 7b and 7c, each of the conditioner devices comprising a conditioner. A rotating arm 9 for holding the head 8 and a cleaning basin 1 for each of the conditioner heads 8
0. The base 1 also supports a transfer station 11 arranged in a square relationship with the three polishing stations 3a, 3b and 3c. The transfer station 11 has a number of functions, including the function of receiving individual wafers from a transfer device (not shown), rinsing them, and retaining them during polishing. A function of transferring them to a wafer head (details will be described later), a function of receiving wafers from the wafer head, a function of cleaning them, and a function of finally returning them to a transfer device (not shown). It also has the function of cleaning the wafer head after the wafer has been unloaded.

Two cleaning stations 12a and 12b
Is located between adjacent ones of the polishing stations 3a, 3b and 3c, and a third washing station 12c is located between the terminal polishing station 3c and the transfer station 11. By these,
The wafer is rinsed while passing from polishing station to polishing station and to transfer station 11.

The rotating multi-head carousel 13 has four wafer head systems 14a, 14b, 14c and 14d, which receive and hold the wafers, and transfer them to the polishing station 3.
Polishing is performed by pressing each of the polishing pads 5 held on the respective platens 6 of a, 3b and 3c. The carousel 13 is supported on a center post 15 and is rotated about a carousel axis by a motor assembly located inside the base 1.

The four wafer head systems 14a, 1
4b, 14c and 14d individually represent the carousel support plate 1
6 are mounted at equal angular intervals around the carousel axis 17. The center post 15 supports the carousel support plate 16 at its center, and the carousel motor (not shown) connects the carousel support plate 16, the wafer head systems 14a, 14b, 14c and 14d and the accompanying wafer. , Around the carousel axis 17.

The wafer head systems 14a, 14b,
Each of 14c and 14d has a wafer head 18, which is rotated about its own axis by a head rotation motor 19 connected thereto by a shaft. The head 18 can be rotated by being driven by a dedicated head rotation motor 19 (one of which is shown with one of the carousel quarter covers 20 removed), and furthermore, has a carousel support. Board 1
It is possible to reciprocate independently and radially in a slot 21 formed in 6. The lifting and lowering of the wafer on the bottom of the wafer head 18 is performed in the wafer head system 14. Wafer head 18
The vertical stroke required to receive the wafer and position the wafer for polishing and cleaning is contained within the wafer head 18.

During actual polishing, three of these wafer head systems (eg, 14a, 14b and 14c)
Of the polishing station 3
Positioned above each of a, 3b and 3c, each of the polishing stations is wet with a polishing slurry in which the surface of the polishing pad 5 acts as a medium for polishing the wafer. During polishing, the wafer head systems 14a, 14b
And 14c independently reciprocate along respective radii of the carousel 13, so that each wafer head 18 independently reciprocates along the diameter of each polishing pad 5.

In use, for example, the fourth wafer head system 14 d is initially located above the wafer transfer station 11. When the carousel 13 rotates, the wafer head systems 14a, 14b,
14c and 14d are arranged above the polishing stations 3b and 3c, the transfer station 11 and the polishing station 3a, respectively. With the carousel 13, each of the wafer head systems 14 is first arranged in sequence above the transfer station 11,
Located one or more above the polishing station 3,
Then, it is returned to the transfer station 11.

Each of the polishing pads 5 is continually or intermittently conditioned by one of the pad conditioners 7, and each of the pad conditioners is independently and separately mounted on a conditioner arm 9. It has a rotating conditioner head 8. It is necessary to have a wear conditioning pad or similar conditioning surface at the bottom of the conditioner head 8. The arm 9 causes the conditioner head 8 to sweep the entire surface of each polishing pad 5 by reciprocating motion between the center and the periphery of the polishing pad 5. The conditioner head 8 is pressed by the pad 5, wears the pad, and performs conditioning.

According to this apparatus, it can be used for various types of polishing sequences.
Here, three main processes are an in-line process, a multi-step process, and a batch process.

When the one-stage polishing is performed in an in-line process, the polishing operation is divided into three steps in separate polishing stations 3, and these steps are substantially equivalent. The same slurry as a polishing pad of the same type has three polishing stations 3a, 3
b and 3c. The wafer head 18 carries the wafer to each polishing station in turn, and at each polishing station, a total of three polishings are performed.
A fraction is done.

In a multi-step process, the polishing process is divided into a number of different processes, and polishing typically proceeds gradually. For example, in the first polishing station 3a, the wafer is roughly polished, in the second polishing station 3b, fine polishing is performed, and in the third polishing station 3c, the wafer is buffed. Buffing is a very delicate polishing, mainly to remove loose foreign matter from the surface. The policing strength is
It depends on the slurry composition, pad material, and other polishing factors. However, the multi-step process has an inherent throughput problem because not all three polishing steps are performed at the same time.

In the batch process, polishing of a plurality of wafers is simultaneously completed completely at each polishing station. Three polishing stations 3a, 3
For b and 3c, the same type of pads are mounted and supplied with the same type of slurry, and polishing of each wafer is completed in one polishing station. That is,
An unpolished wafer is provided to three polishing stations simultaneously.

The differences between an in-line process, a multi-step process, and a batch process are not clearly defined, and a process having one or more of these characteristics may be selected. For example, equivalent in-line or batch polishing is performed using two polishing stations 3a and 3b, and multi-step fine polishing or buffing may be performed in the third polishing station 3c.

[0021]

According to the above-mentioned apparatus, when used in an in-line process, the polishing time is somewhat long, and the cleaning and the transfer of wafers are completed during polishing. T ₁ time, ignoring the travel time of the carousel, the first two subsequent another T _1/3 (= polishing station 3
There is no problem of finishing one sheet each time.

In the case of a multi-step process such as a two-step process, the required polishing time of the first step is T ₃ ,
The necessary policing time in stages and _{T 4, T 3> T 4} > T 3
/ 2, the polishing stations 3a and 3b
The policing station 3c is assigned to the second stage. In this case, it is necessary to sufficiently clean the cleaning station 12b between the polishing station 3b and the polishing station 3c. Therefore the T ₅ from polishing station 3b including the moving time and the washing time to polishing stations 3c, if those completed during the ride of the last wash and the wafer exchange is policing, the first two alternative subsequent T ₄ as
And thus one Shiagariru every + T _5. Here since the first stage of polishing is despite previous wafer has been completed can not be moved well is washed in the cleaning station 12b because it is during polishing of the second stage T ₅
Time is required separately. As described above, when the first-stage polishing is completed, and the standby is performed without cleaning as it is, if the standby time is too long, the abrasive is firmly adhered to the abrasive, and the cleaning becomes difficult.
₅ tends to be long, and the coarse abrasive tends to enter the finishing polishing station 3c without being completely washed. Furthermore, if the slurry used for the first-stage polishing is highly corrosive, it cannot be washed immediately, so that the surface of the wafer is corroded and the smoothness is impaired.

When used in the batch process of the one-stage polishing, one of three wafer heads 18 can be attached and detached during polishing of the wafers of the other wafer heads 18. Therefore, the wafer is moved to the transfer station 11 for attaching and detaching the wafers. The cleaning time must be separately set, and the efficiency is better when used in an in-line process.

Accordingly, the present invention provides a planar polishing apparatus which is a general-purpose type but has an improved index in a multi-step process, particularly in a two-step step polishing, and which has an index comparable to the above-mentioned apparatus even when one-step polishing is performed. .

[0025]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a transfer station, a plurality of polishing stations arranged so as to surround the transfer station, and
The same number of the polishing stations and each independently moving wafer head, comprising a cleaning station provided corresponding to each wafer head,
The transfer station is provided with a plate to be polished, where the wafer head receives the plate and returns the polished plate to and from which the polishing is performed. Each of the stations has a rotating platen, and the wafer head is vertically movable by sucking and holding the wafer on the lower surface, and is rotatable for polishing, and is provided with two adjacent portions of the polishing station. The transfer station and the cleaning station are provided so as to be horizontally movable so as to be accessible, and adjacent wafer heads are sequentially arranged so as to share one of two accessible polishing stations. In the cleaning station, the wafer head holds the plate-shaped material by suction. Providing a planar polishing apparatus characterized in that for cleaning is location. According to this apparatus, when one-stage polishing is performed, each wafer head processes the entire polishing time at one polishing station. Since each wafer head moves independently, it is not disturbed by other wafer heads except for the time at the transfer station shared by each wafer head. Therefore, the operation at the transfer station, that is, the timing of the transfer of the plate material is shifted only, and each wafer head is moved every (the transfer time of the plate material including the movement) + (polishing time) + (the cleaning time including the movement). Process one sheet. When applied to two-stage polishing, a polishing station is assigned to every other location in the first stage and the rest is assigned to the second stage. Then, since the wafer head can access two adjacent polishing stations, two-stage polishing can be performed with them. However, in this case, the wafer head can operate independently, but the polishing station is shared with the adjacent wafer head. Therefore, if the polishing time of the second step is long, it is necessary to wait for the polishing after the completion of the first step. However, since a cleaning station is provided corresponding to each wafer head, it is possible to immediately proceed to cleaning and wait while cleaning, so that the polishing station is vacant before the second stage polishing is started. If the first step is long, a waiting time occurs when the processing of the previous plate-like material is completed and the next plate-like material is polished. However, here, it is not necessary to wait while cleaning. In each case, each wafer head performs one processing per approximately twice as long as the longer polishing time. It is preferable to provide a transfer device that supplies the plate material to be polished to the transfer station and takes out the polished plate material returned therefrom. or,
In particular, as an efficient configuration for performing the two-stage polishing, the number of polishing stations and the number of wafer heads are preferably 2N (N is a positive integer).

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view conceptually showing this.
This polishing apparatus has a transfer station 61 substantially at the center. The transfer station 61 can have many functions like the conventional device. The main function is wafer 50
And a function of receiving the wafer
(Hereinafter referred to as a wafer) 50, a function of receiving the wafer 50 from the wafer head 52, and a function of returning them to the transfer device 51. Further, here, cleaning or drying may be performed before, during or at the end of polishing using a liquid or a gas. Known mechanisms can be applied to the mechanism for providing these functions, and illustration is omitted.

A plurality of, for example, four polishing stations 53 surround the transfer station 61.
a, 53b, 53c and 53d are arranged in a rectangular shape.
As shown in FIG.
3b are close to each other, and there is an interval between the polishings 53a and 53d. This is because the transfer station 61 during polishing at the polishing stations 53a and / or 53d.
To (or from) the wafer. Polishing stations 53a, 53
Each of b, 53c and 53d has a rotating platen (not shown), and in the case of chemical mechanical polishing, a polishing pad (not shown) thereon
Is arranged. In addition, a pad conditioner device and a slurry supply mechanism are provided, but are not shown.

The wafer heads 52a, 52b, 52c,
Reference numerals 52d are attached to the rotating arms 54 so as to hang them, and hold the wafer by suction on the lower surface. And
The arm 54 can be moved up and down in order to change the height position during polishing, movement and wafer transfer. Furthermore, it rotates for polishing. Each arm 5
4 is an arm shaft 55a extending downward from a housing (not shown);
b, c, d attached to the tip of the arm shaft 55a,
It rotates freely by the rotation of b, c, d. Arm shaft 55
a is fixedly arranged so that the wafer head 52a can be positioned at a predetermined position of each of the polishing station 53a and the polishing station 53d by rotation, and can be positioned at the center of the transfer station 61. Similarly, the arm shaft 55c rotates the wafer head 52c by rotating the polishing head 53c.
b and the polishing station 53c are fixedly arranged so that they can be located at predetermined positions of the respective polishing stations 53c and can be located at the center of the transfer station 61.
On the other hand, the arm shaft 55b is
a first position (the state shown in FIG. 1) where b can be positioned at a predetermined position of each of the polishing station 53a and the polishing station 53b by rotation, and a second position where b can be positioned at the center of the transfer station 61. Is provided so as to be movable. Similarly, the arm shaft 55d has a first position (FIG. 1) where the wafer head 52d can be positioned at a predetermined position of each of the polishing station 53c and the polishing station 53d by rotation.
) And a second position that can be positioned at the center of the transfer station 61.

Then, each of the wafer heads 52a, b, c,
d corresponding to each of the cleaning stations 56a, b,
c and d are provided. Here, the cleaning station 56b,
d is a position where the wafer heads 52b and 52d can be respectively arranged when the arm shafts 55b and 55d are at the first position. These washing stations 5
Numeral 6 is for cleaning the wafer while the wafer head 52 holds the wafer by suction, and may be a type which blows up water in a shower shape, or a type in which water blows up from the container and overflows. Alternatively, cleaning using a brush that does not damage the wafer may be used.

A loader (not shown) for mounting the supply-side wafer carrier 62 and an unloader (not shown) for mounting the unloading-side wafer carrier 63 are provided. Then, the wafer carriers 62 and 63 are sequentially raised or lowered to set a height for taking out or storing the wafer 50.

Further, the transfer device (robot hand) 51a which pulls out the wafer 50 stored at the position of the supply-side wafer carrier 62 and sets it at the transfer station 61, and the height of the unloading-side wafer carrier 63 is adjusted. Transfer device (robot hand) for transferring and storing the wafer 50 placed in the transfer station 61 at the closed position
51b. Of course, it is also possible for one transfer device to serve as both.

In this polishing apparatus, each wafer head 52 can access two polishing stations 53 and can operate independently. The rotating platen (not shown) arranged at each polishing station 53 can also independently control the rotating speed. At the time of the polishing operation, each wafer head 52 attracts the wafer 50 and descends, and is positioned on a rotating platen (not shown), and is wet with a polishing slurry acting as a medium for polishing the wafer. Of the polishing pad (not shown). Then, the wafer head 52 rotates on its own and swings on a rotating platen (not shown) by reciprocating rotation of the rotating arm 54 at a predetermined angle.

According to this apparatus, it can be used for various types of polishing sequences. One-stage process and multi-step process. It is particularly suitable for a two-stage process among multi-step processes, but can also be used for a three-stage or four-stage process. In the case of three or more stages, when the two stages have been completed, the wafer is returned to the transfer station 61 and another wafer head 52 is in charge of the subsequent processing.

In the one-stage process, the polishing operation is performed by
Each polishing station 53 is used to process another wafer 50 under the same conditions. Each wafer head 52 has access to only one polishing station 53. Each polishing station performs all necessary polishing.

FIG. 2 shows the operation of the one-stage process by this apparatus.
The description is also given using the time chart shown in FIG. Assuming that the polishing time is somewhat longer and the cleaning and wafer transfer are shorter than the polishing time, the necessary polishing time is T ₁ , the cleaning time (including moving time) is T ₅ , and the wafer transfer, that is, the processed wafer Is placed in the transfer station 61, the wafer is taken out to the take-out side wafer carrier 63, the wafer is carried from the supply side wafer carrier 62 to the transfer station 61, the wafer is sucked and held by the wafer head 53 and moved to the polishing station 53, and polishing is performed. the time to begin to T _10. The current wafer head 52a has finished processing the previous wafer and is still holding the wafer. The other wafer heads 52b, 52c, and 52d
Is maintained during polishing and cleaning.

(1) First, the wafer is transferred to the wafer head 52a. That is, the rotation operation of the rotary arm 54 moves the wafer head 52a to the transfer station 61, moves down, places the processed wafer 50 in the transfer station 61, and then raises it.
a removes the wafer 50 from the supply-side wafer carrier 62 and places it in the transfer station 61, so that the wafer head 52a descends, adsorbs a new wafer 50, and moves up to the polishing station 53a by the rotation of the rotating arm. Then, polishing is started by pressing against a polishing pad (not shown) arranged on a platen (not shown) rotating and moving down. (Time T ₁₀ ) (2) During the polishing for a predetermined time (T ₁ ), the wafer head 52 a rotates and the rotation arm 54
Swing action by the movement of. (3) When the polishing for the predetermined time T ₁ is completed, the wafer head 52a is raised and moved to the cleaning station 56a by the rotation of the rotary arm 54 to perform the cleaning. (Time T ₅₎ or by one cycle at the wafer head 52a is repeated with subsequent this operation end. Although policing Similarly, in the meantime wafer head 52b is carried out the transfer station 61 and conveyors 51a, b is the operation delayed operates only put replacement operation time because it is shared for example wafer head 52a (T _10). Similarly, each of the wafer heads 52c and 52d performs the same operation as the previous wafer head. Of course policing time T ₁ and depending on the relationship with other time in some cases latency occurs.
Polishing time T ₁ in the case of this embodiment does not cause large latency. Then, as shown in FIG.
The other wafer heads each complete one wafer 50 during one cycle of 2a. Therefore, this apparatus requires (T ₁ + T ₅ + T ₁₀ ) / 4 time per sheet.
Wherein T ₁ is in the very long compared to the other times (which includes four similar this embodiment the wafer head) apparatus shown in FIG. 5 per sheet in the case of 1-step process in-line process faster than the time required T _1/3 (= the number of polishing stations 3). However, if the number of polishing stations is increased to four in the apparatus shown in FIG.
Required time per sheet is likely to be slightly faster or equal to this embodiment becomes T _1/4.

A multi-step process, for example, a two-step process will be described with reference to time charts shown in FIGS. FIG. 3 shows the required policing time of the first stage as T
₃ , the required policing time in the second stage is T _4, and T ₃ >
It is the case of T _4. FIG. 4 shows the case where T ₃ <T ₄ . For example, it is assumed that the polishing stations 53a and 53c are assigned to the first stage, and the polishing stations 53b and 53d are assigned to the second stage. Intermediate washing, the washing time includes travel time from the polishing station 53 to the cleaning station 56 for the final washing and T _5. Then, the time of the wafer carrying replacement and T _10. First, T ₃ >
In the case of T ₄ will be described. During the continuous processing, the current wafer head 52a sets a new wafer in the first position.
It is assumed that the step polishing is started. The other wafer heads 52b, 52c, and 52d hold the wafer 50, respectively, and are in the process of polishing and cleaning.

(1) While polishing is performed for a predetermined time (T ₃ ) at the polishing station 53a, the wafer head 52a rotates by itself and swings by the movement of the rotary arm 54. (2) moves to the cleaning station 56a by the rotation operation of the rotating arm 54 by the wafer heads 52a rises After completion policing of the predetermined time T ₃ is cleaned for a predetermined time. (Time T ₅ ) (3) If the polishing station 53d is closed, it stands by while washing, and if the polishing station 53d is empty, the wafer head 52a rises and moves to the polishing station 53d by the rotating operation of the rotary arm 54, and descends. Then, the wafer 50 is pressed against a polishing pad (not shown) arranged on a rotating platen (not shown) to perform a second-stage polishing. (Time T ₄ ) In this case, since the time T ₄ is short, it is vacant and immediately starts the second-stage polishing. While the polishing is performed for a predetermined time (T ₄ ), the wafer head 52a rotates by itself and swings by the movement of the rotating arm 54. (4) to clean the moving wafer head 52a rises After completion policing of the predetermined time T ₄ to the cleaning station 56a by the rotation operation of the rotating arm 54 a predetermined time (T _5). (5) Then, the wafer 50 is transferred to the wafer head 52a. That is, the rotation operation of the rotary arm 54 moves the wafer head 52a to the transfer station 61 and descends to transfer the processed wafer 50 to the transfer station 61.
Then, the take-up side transfer device 51b takes out the wafer 50 and packs it in the take-out side wafer carrier 63. Meanwhile, the supply-side transfer device 51a removes the wafer 50 from the supply-side wafer carrier 62 and places it on the transfer station 61, so that the wafer head 5
2a descends, attracts a new wafer 50, and rises. (Time T ₁₀ ) Here, the polishing station 53
If a is vacant, it is moved to the polishing station 53a by the rotation of the rotary arm, and is pressed against a polishing pad (not shown) arranged on a platen (not shown) rotating and moving down to the first stage. Policing starts, but waits if it is not empty. The waiting time T _X occurs because in this case T3 is long. Thus, one cycle in the wafer head 52a is completed, and thereafter, this operation is repeated.

In the meantime, polishing is performed in the wafer head 52b in the same manner, but the first-stage polishing uses the polishing station 53a in common with the wafer head 52a, so that the timing coincides with the movement of the wafer head 52a. Furthermore, since the transfer station 61 and the transfer devices 51a and 51b are shared, it is necessary to set the timing so that they do not overlap. Thus, for example, as shown in FIG.

In the meantime, polishing is performed in the wafer head 52c in the same manner, but since the transfer station 61 and the transfer devices 51a and 51b are shared, it is necessary to set the timing so that they do not overlap. Therefore, for example, the wafer head 5
2a to become the timing diagram 3 of which send only put replacement time T ₁₀ of the wafer.

In the meantime, polishing is similarly performed on the wafer head 52d, but the first-stage polishing uses the polishing station 53c in common with the wafer head 52c, so that the timing coincides with the movement of the wafer head 52c. Further, in the second stage polishing, the polishing station 53d is shared with the wafer head 52a, so that the wafer must be moved after the wafer head 52a is moved. Furthermore, since the transfer station 61 and the transfer devices 51a and 51b are shared, it is necessary to set the timing so that they do not overlap. Thus, for example, as shown in FIG. As shown in FIG. 3, the first stage polishing time T ₃
If it is sufficiently long and the difference from the polishing time of the second step is to absorb all of the cleaning time T ₅ and put replacement time T ₁₀ is the time they not appear in the process cycle, each wafer head 2 *
T to process one wafer every _three hours.

Next, the case of T ₃ <T ₄ will be described with reference to FIG. The polishing stations 53a and 53c are assigned to the first stage, and the polishing stations 53b and 53d are allocated.
From the polishing station 53 to the cleaning station 56 for cleaning and final cleaning.
Points to T ₅ the washing time includes travel time to the point that the T ₁₀ time wafer carrying replacement is similar to FIG. During the continuous processing, the current wafer head 52
“a” indicates that the second stage polishing has started. The other wafer heads 52b, 52c, and 52d hold the wafer 50, respectively, and are in the process of polishing and cleaning.

(1) Polishing is performed for a predetermined time (T ₄ ) in the polishing station 53d. (2) wafer head 52a After completion policing of the predetermined time T ₄ is moved to the cleaning station 56a performs a cleaning of the predetermined time. (Time T ₅₎ (3) then performs the exchange placed the wafer 50 to the wafer head 52a. (Time T ₁₀₎ (4) waiting if busy polishing station 53a is, if drilled polishing station 53a moves to the wafer head 52a polishing station 53a, to police the first stage. (Time T ₃ ) In this case, since the time T ₃ is short, it is vacant and immediately starts the second-stage polishing. (5) a wafer head 52a After completion policing of the predetermined time T ₃ is cleaned for a predetermined time to move to the cleaning station 56a (T _5). (6) Here, if the polishing station 53d is vacant, the second-stage policing starts, but if not, the process stands by until it is vacant. The waiting time T _X occurs because in this case T ₄ is long. Thus, one cycle in the wafer head 52a is completed, and thereafter, this operation is repeated.

In the meantime, polishing is similarly performed on the wafer head 52d, but the second-stage polishing uses the polishing station 53d in common with the wafer head 52a, so that the timing coincides with the movement of the wafer head 52a. Furthermore, since the transfer station 61 and the transfer devices 51a and 51b are shared, it is necessary to set the timing so that they do not overlap. Thus, for example, as shown in FIG.

In the meantime, polishing is similarly performed on the wafer head 52c, but since the transfer station 61 and the transfer devices 51a and 51b are shared, it is necessary to set the timing so that they do not overlap. Therefore, for example, the wafer head 5
2a to become like Figure 4 of timing delayed by carrying replacement time T ₁₀ of the wafer.

In the meantime, polishing is similarly performed on the wafer head 52b. However, since the polishing on the second floor shares the polishing station 53b with the wafer head 52c, the timing is synchronized with the movement of the wafer head 52c. Thus, for example, FIG. In this case the first stage of the polishing time T ₃ is short enough and the difference from the polishing time of the second stage cleaning time T as shown in FIG. 4 also ₅
If you absorb all or carrying replacement time T ₁₀ is not reflected in the time of their processing cycle, each wafer head to process one wafer every 2 * T ₄ hours. Here, FIG. 5 device shown in (a wafer head this embodiment similar four provided ones) is a necessary policing time brother two stages and T ₄ when the required polishing time of the first stage second stage Step T _3, T ₃
> T _4> T _3/2 and then, if the one Shiagariru this embodiment cleaning time in every T ₄ + T ₅ When T ₅ as of _{2 * T 3/4 = T} 3/2 < has become faster because the finished every T _4. Further, T _3/2> For T ₄ but so that the finished every T _3/2 + T ₅ in the case of the apparatus of FIG 5 fast since it processes one every T _3/2 in the case of this embodiment.

[0047] The apparatus of FIG. 5 and the same polishing speed station this embodiment the four portions, therefore T ₃ the wafer head as _{5> T 3/2> T 4} > For T _4/2 T ₃ /
For 2 + T can one treatment every ₅ This example T ₃ /
It is fast because it can process every two. In _{addition, T 3> T 3/2} > T 4>
_{T 3/3 T 4 + T} 5 towards this embodiment is fast required in the case of.

The operation of the two-stage polishing has been described in the case where the difference between the time of the first-stage polishing and the time of the second-stage polishing is large. In some cases, the occurrence of the waiting time becomes complicated due to the time and the cleaning time.

As described above, according to this embodiment, a high index can be obtained when applied to one-stage polishing, which is comparable to the conventional apparatus shown in FIG. 5, and particularly when applied to two-stage polishing.

Although the above embodiment has been described with reference to a chemical mechanical polishing apparatus, the present invention can be similarly applied to a mechanical polishing apparatus.

[0051]

As described above, according to the apparatus of the present invention, a general-purpose planar polishing apparatus can be used for one-step polishing for high-speed processing, and particularly for two-step polishing for high-speed processing.

[Brief description of the drawings]

FIG. 1 is a plan view conceptually showing an embodiment of the present invention.

FIG. 2 is a time chart when one-stage polishing is performed by the apparatus of the embodiment.

FIG. 3 is a time chart when two-stage polishing is performed by the apparatus of the embodiment (when the polishing time of the first stage is long).

FIG. 4 is a time chart when two-stage polishing is performed by the apparatus of the embodiment (when the polishing time of the second stage is long).

FIG. 5 is a perspective view of a conventional planar polishing apparatus.

[Explanation of symbols]

50 Wafer (plate-like material) 51a, 51b Robot arm (transfer device) 52a, 52b, 52c, 52d Wafer head 53a, 53b, 53c, 53d Polishing station 54 Rotating arm 56a, 56b, 56c, 56d Cleaning station 61 Transfer station

Claims (5)

[Claims] 1. A transfer station, a plurality of polishing stations arranged so as to surround the transfer station, the same number of the polishing stations and independently moving wafer heads, and a plurality of wafer heads corresponding to the respective wafer heads. A cleaning station provided, wherein the transfer station is provided with a plate to be polished, where the wafer head receives the plate and returns the polished plate to it. The polishing stations each have a rotating platen, and the wafer head is vertically movable while holding and holding a wafer on a lower surface, and is capable of rotating for polishing and the polishing station. Washing between two adjacent places, the transfer station A plurality of polishing stations, each of which is horizontally movable so as to be accessible to a polishing station, and adjacent wafer heads are sequentially arranged so as to share one of two accessible polishing stations. A planar polishing apparatus characterized in that a head is arranged for cleaning while holding a plate-shaped material by suction. 2. The wafer head is attached to a rotating arm so as to be vertically movable and freely rotatable with respect to the rotating arm. The movement to the two polishing stations and the cleaning station is performed by rotating the rotating arm. The planar polishing apparatus according to claim 1, wherein the polishing is performed by an operation. 3. The flat polishing machine according to claim 1, further comprising a conveying device for supplying the plate material to be polished to the transfer station, and removing the polished plate material returned therefrom. apparatus. 4. The apparatus according to claim 1, wherein the number of polishing stations and the number of wafer heads are each 2N (N is a positive integer). 5. The apparatus according to claim 1, wherein the number of polishing stations and the number of wafer heads are four.