JP2000024910A - Grinding method and device for wafer and manufacturing of wafer by using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely grind a wafer under the same grinding condition by sending a dummy wafer to each wafer retaining head. SOLUTION: A head loading module 16 receives a wafer W and a dummy wafer W' adsorbed and conveyed by a convey robot 14 on its loading part 161 at a point of a rotatable arm 160 in the delivery position A from the convey robot 14. A grinding part 17 for grinding the surfaces of the wafer W and the dummy wafer W' is mounted in adjacent to the head loading module 16. The grinding part 17 comprises a rotatable platen 170 comprising a grinding pad on its upper surface, a rotatable carousel at an upper part of the platen 170, and a plurality of heads rotatably mounted at a lower outer edge part of the carousel at specific intervals. The wafer W and the dummy wafer W' of the loading part 161 of the head loading module 16 are pressed to a lower surface part of the head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing method and a polishing apparatus for polishing a surface of a semiconductor wafer or the like forming an integrated circuit, and a method of manufacturing a wafer using the polishing apparatus.

[0002]

2. Description of the Related Art A wafer polishing apparatus of this type includes a disk-shaped platen having a polishing pad attached to a surface thereof, and a plurality of wafer polishing apparatuses for holding one surface of a wafer to be polished and bringing the other surface of the wafer into contact with the polishing pad. It is widely known to provide a wafer holding head and perform polishing by supplying a slurry containing abrasive grains between a polishing pad and a wafer while relatively moving these wafer holding heads and the platen. I have.

As one example, there is disclosed a wafer holding head adopting a floating head structure having an advantage that a contact pressure of a wafer against a polishing pad can be made uniform (US Pat. No. 5,205,0).
No. 82).

As shown in FIG. 4, the wafer holding head includes a hollow head main body 1, a diaphragm 2 stretched horizontally in the head main body 1, and a carrier 3 fixed to the lower surface of the diaphragm 2. The carrier 3 is pressed downward by supplying pressurized air from a pressurized air source 6 through a shaft 5 to an air chamber 4 defined by the diaphragm 2.

[0005] A retainer ring 7 is arranged on the outer periphery of the carrier 3 so that the lower end protrudes below the carrier 3. The retainer ring 7 holds the outer periphery of the wafer attached to the lower surface of the carrier 3, and holds the wafer being polished. A problem such as detachment from the carrier 3 is prevented.

[0006]

By the way, wafers to be polished in the above-mentioned conventional polishing apparatus require strict product management. Generally, a predetermined number of wafers (for example, 25 wafers) are stored in a wafer cassette. It is managed on a wafer cassette basis. In the conventional polishing apparatus, when the number of wafer holding heads that hold and simultaneously polish wafers does not match the common divisor of the number of wafers stored in the wafer cassette (for example, when six wafers are provided). However, there is a problem in that, when the wafers are sequentially polished, a fractional number of wafers is left at the end in number of the wafer holding heads. In this case, if only this fractional wafer is directly used in the polishing apparatus, there is a problem that polishing conditions are different from those of other wafers.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably polish a large number of wafers stored in a wafer storage section under the same polishing conditions. Another object of the present invention is to provide a wafer polishing method and a polishing apparatus capable of smoothly continuing polishing of a large number of wafers without interruption, and a method of manufacturing a wafer using the polishing apparatus.

[0008]

According to a first aspect of the present invention, a platen having a polishing pad adhered to a surface thereof and one surface of a wafer to be polished are held, and the other surface of the wafer is brought into contact with the polishing pad. A plurality of wafer holding heads,
In a wafer polishing method of polishing the other surface of the wafer with the polishing pad by the relative motion between the wafer holding head and the platen, the wafer is sequentially supplied to each wafer holding head from a wafer storage unit that stores a large number of wafers. Then, while polishing these wafers, the remaining unpolished wafers in the wafer storage section,
When it becomes less than the number of wafer holding heads,
A dummy wafer having the same shape and the same material as the wafer is supplied to each of the wafer holding heads together with the remaining unpolished wafer to polish the wafer.

According to a second aspect of the present invention, the wafer and the dummy wafer after polishing are washed and dried and returned to the wafer storage section and the dummy wafer storage section.

A third aspect of the present invention is a platen having a polishing pad attached to a surface thereof, and a plurality of wafer holding heads holding one surface of a wafer to be polished and bringing the other surface of the wafer into contact with the polishing pad. In a wafer polishing apparatus for polishing the other surface of the wafer with the polishing pad by the relative movement between the wafer holding head and the platen, a wafer storage section for storing a large number of wafers, and the same shape as the wafer And a dummy wafer storage unit that stores dummy wafers of the same material, and a transfer unit that is provided between the wafer storage unit and the dummy wafer storage unit and each of the wafer holding heads, and that transfers the wafer and the dummy wafer. It is provided with.

According to a fourth aspect of the present invention, there is provided a method comprising the steps of:
A cleaning and drying unit for cleaning and drying the wafer and the dummy wafer is provided.

In the method and apparatus for polishing a wafer according to the first and third aspects, when the number of remaining unpolished wafers in the wafer accommodating portion becomes smaller than the number of wafer holding heads, the remaining number of unpolished wafers is reduced. By supplying a dummy wafer of the same shape and the same material as the above wafer together with the unpolished wafer to each of the above wafer holding heads and polishing the wafer, all the wafers stored in the wafer storage unit have the same polishing conditions. And the polishing of a large number of wafers is smoothly continued without interruption.

In the method and apparatus for polishing a wafer according to the second and fourth aspects of the present invention, the wafer and the dummy wafer after polishing are washed and dried to return to the original wafer storage section and the dummy wafer storage section. By returning,
A series of steps involved in the polishing step are smoothly performed while taking into account the quality control of the wafer. According to a fifth aspect of the present invention, a wafer is manufactured by polishing the surface of the wafer using the polishing apparatus according to the third or fourth aspect. In the method of manufacturing a wafer according to the fifth aspect, a predetermined number of wafers are continuously polished under the same conditions even if a fraction occurs in the polishing step, so that a large number of wafers of the same quality can be obtained. Wafers are manufactured smoothly and easily.

[0014]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. Reference numeral 10 in these figures
Is a wafer storage unit that stores a large number of wafers W,
A dummy wafer storage unit 11 for storing a dummy wafer W ′ having the same shape and the same material as the wafer W is provided adjacent to the wafer storage unit 10.

In each of the wafer storage unit 10 and the dummy wafer storage unit 11, for example, a wafer cassette capable of storing 25 wafers is mounted, and two wafers are stored in the wafer storage unit 10. A cassette is mounted, and one wafer cassette is placed in the dummy wafer storage unit 11, respectively.

Adjacent to the wafer storage section 10 and the dummy wafer storage section 11, these wafer storage sections 1
A single articulated robot 13 that mounts the wafers 0 and 11 or the dummy wafer W ′ on the mounting table 12 is provided. The articulated robot 13 has a pair of support claws 1.
Reference numeral 30 is used to support and transport the outer edge of the wafer W or the dummy wafer W 'in each of the wafer storage sections 10 and 11.

In the mounting table 12, the wafers W or the dummy wafers W 'sent from the respective wafer storage sections 10 and 11 are stacked in multiple stages (for example, six stages) with a predetermined interval therebetween. It is configured as follows. Further, adjacent to the mounting table 12, the mounting table 1
A transfer robot 14 for transferring the wafer W or the dummy wafer W 'on the second wafer 2 is provided. The transfer robot 14 is configured to adsorb the center of the wafer W or the dummy wafer W ′ by a forked bifurcated end of an arm 140 that can move forward and backward, and is rotatable, and has a linear transfer path 141. The wafer W or the dummy wafer W 'is transported to the transfer position A in the polishing chamber 15.

In the polishing chamber 15, a head loading module 16 for receiving the wafer W or the dummy wafer W 'from the transfer robot 14 is provided. The head loading module 16 transfers the wafer W or the dummy wafer W ′ sucked and transferred by the transfer robot 14 at the transfer position A with the transfer robot 14.
It is received by the mounting portion 161 at the tip of the rotatable arm 160.

Then, adjacent to the head loading module 16, the wafer W or the dummy wafer W '
There is provided a polishing section 17 for polishing the surface. The polishing unit 17 includes a rotatable platen 170 having a polishing pad adhered to an upper surface thereof, a carousel 171 rotatably provided above the platen 170, and a carousel 1
A plurality of (for example, six) heads (wafer holding heads) 172 rotatably provided at predetermined intervals on the outer edge of the lower surface of the head 71, and the head loading module 16 The wafer W or the dummy wafer W ′ of the mounting portion 161 is pressed.

Further, adjacent to the polishing section 17, a transfer position B
A head loading module 18 for carrying out the head is provided. The head loading module 18 has a configuration similar to that of the head loading module 16 and places a polished wafer W or a dummy wafer W ′ on a placement section 181 at the tip of a rotatable arm 180. Then, it is carried out to the delivery position B.

At the transfer position B, a transfer robot 19 for receiving the wafer W or the dummy wafer W ′ from the head loading module 18 is provided adjacent to the polishing chamber 15. This transfer robot 1
Numeral 9 is adapted to adsorb the central portion of the wafer W or the dummy wafer W 'by the forked bifurcated end of the arm 190 which can be moved forward and backward, and which is rotatable. The wafer is lifted and carried out to the wafer standby unit 21 of the cleaning unit 20.

The wafer waiting section 21 has a space for accommodating a large number (for example, 6 + emergency 6) wafers W or dummy wafers W '. Wash with water
Further, drying of the wafer W or the dummy wafer W 'is prevented.

Further, below the wafer waiting section 21, a wafer W
Alternatively, a first scrub portion 22 for cleaning by pressing a brush or the like against both surfaces of the dummy wafer W 'is provided.
A second scrubbing part 23, which is adjacent to the wafer waiting part 21 and the first scrubbing part 22 and is cleaned by pressing a brush or the like against both surfaces of the wafer W or the dummy wafer W 'using pure water, and hydrofluoric acid. And a chemical cleaning unit 24 for cleaning the wafer W or the dummy wafer W ′ using
It is arranged up and down.

These wafer standby units 21, the first and second
Two transfer robots 25 for transferring the wafer W or the dummy wafer W ′ are provided between the scrubbing units 22 and 23 and the chemical cleaning unit 24 by the wafer standby unit 21 and the first and second wafers.
The scrubbing parts 22 and 23 and the chemical cleaning part 24 are arranged to face each other.

Adjacent to the chemical cleaning section 24, a transfer robot 27 for transferring the wafer W or the dummy wafer W 'which has completed the chemical cleaning in the chemical cleaning section 24 to the rinse drying section 26 is provided. The transfer robots 25 and 27 support and transfer the outer edge of the wafer W or the dummy wafer W '.

The rinsing drying section 26 cleans the wafer W or the dummy wafer W 'after the chemical cleaning with pure water and spin-drys it by centrifugal force. Further, the wafer W or the dummy wafer W ′ after the spin drying is completed is returned to the wafer storage section 10 or the dummy wafer storage section 11 by the articulated robot 13.

The articulated robot 13, the transfer robot 14, the head loading modules 16 and 18,
Transfer means for transferring the wafer W and the dummy wafer W ′ is schematically configured by the transfer robots 19, 25, and 27.

Further, the wafer W and the dummy wafer W '
The washing and drying section for washing and drying the
, A main part includes a wafer standby unit 21, first and second scrub cleaning units 22 and 23, a chemical cleaning unit 24, and a rinsing drying unit 26.

The wafer storage unit 10 is adjacent to a clean room for loading and unloading a wafer cassette storing the wafers W, and is maintained at a lower pressure than the clean room.
The inside of the polishing chamber 15 is maintained at the lowest pressure.

Next, a case where the wafer W is polished by the polishing apparatus configured as described above will be described.
First, when two wafer cassettes accommodating a large number of wafers W are carried into the wafer accommodating section 10, the articulated robot 13 is operated to take out the wafers W from the wafer cassettes, and sequentially place the mounting tables 12 Place on top.
Next, the transfer robot 14 transfers the wafer W on the mounting table 12.
And transported to the transfer position A in the polishing chamber 15.

At the transfer position A, the tip of the arm 140 of the transfer robot 14 is placed on the mounting portion 161 at the tip of the arm 160 of the head loading module 16 located below the tip of the arm 140 of the transfer robot 14. Is transferred to the wafer W.

Subsequently, the arm 160 of the head loading module 16 is rotated, and the mounting portion 161 at the tip of the arm 160 is mounted on one of the heads 172 rotatably provided below the carousel 171 of the polishing portion 17. Located one below. Then, the mounting portion 161 of the arm 160 is raised, and the wafer W mounted on the mounting portion 161 is pressed against the lower surface of the head 172 and water-adhered.

Further, by rotating the carousel 171 by a predetermined angle and repeating the above-described transfer operation of the wafer W, the wafer W transferred by the transfer robot 14 is sequentially transferred to each head 172 via the head loading module 16. Paste on the underside.

When the wafers W are all loaded into the six heads 172 in this way, the carousel 171 is lowered together with the heads 172 and approaches the platen 170, and then the platen 170, the carousel 171 and each head 172 are moved. By rotating each head, each head 1
The polishing of each wafer W is started by the relative movement between the plate 72 and the platen 170.

When the polishing of the six wafers W in the polishing section 17 is completed, the head loading module 1
8 by repeating the rotation operation of the arm 180 and the rotation operation of the carousel 171, the wafer W stuck on the lower surface of each head 172 is placed on the mounting portion 181 at the tip of the arm 180 of the head loading module 18. Delivered sequentially and carried out to the delivery position B.

Next, at the transfer position B, the wafer W on the mounting portion 181 at the tip of the arm 180 of the head loading module 18 is sucked up by the tip of the arm 190 of the transfer robot 19 and lifted up.
Is sent to the wafer standby unit 21.

Then, the wafer W to which pure water has been applied in the wafer standby section 21 is transferred to the two transfer robots 2.
5, the first scrub section 22 and the second scrub section 2
3. The cleaning solution is sequentially sent to the chemical cleaning section 24, where the double-sided scrub cleaning processing and the chemical cleaning processing are sequentially performed.

Subsequently, the wafer W that has been subjected to the chemical cleaning process is sent to the rinse drying unit 26 by the transfer robot 27, where the wafer W is cleaned with pure water, and further subjected to spin drying by centrifugal force. The wafer is returned to the original wafer cassette by the joint robot 13.

By performing this operation continuously, six wafers W in one wafer cassette are sequentially polished. When the number of wafers W in the wafer cassette is less than six, the dummy wafer W 'is taken out of the dummy wafer storage unit 11 in place of the insufficient wafer W and transported to the polishing unit 17, Polishing is performed together with W.

Thus, in the polishing section 17, the wafers W can always be polished under the same polishing conditions, and the same polishing process can be performed on all the wafers W.
Next, the wafer W after completion of polishing and the dummy wafer W ′ are subjected to cleaning and drying processes by the same operation as described above, and then the wafer W is stored in the wafer storage unit 10.
In addition, the dummy wafer W 'is
Are returned by the articulated robot 13 respectively.

In this manner, the wafer storage unit 10
When the polishing processing of all the wafers W in the individual wafer cassettes is completed, these wafer cassettes are unloaded, and two new wafer cassettes requiring polishing processing are newly loaded, and the above-described operation is repeated. Since each wafer W subjected to such a polishing treatment is reliably polished under the same polishing conditions, each wafer W manufactured through this polishing step can ensure the same high quality. it can.

The number of wafers W that can be accommodated in the wafer cassette described in this embodiment or the number of wafers W that can be simultaneously polished in the polishing section 17 is not limited to this. When the remaining wafers W in one wafer cassette become fractional in the course of the polishing process sequentially at 17, the dummy wafer storage unit 11 removes the number of dummy wafers necessary for simultaneous polishing of the polishing unit 17. If W 'is supplied, the same effect as in the present embodiment can be obtained.

Further, the dummy wafer W 'in the dummy wafer storage section 11 can be used at the time of starting up the operation of the polishing system of the present embodiment or the like, and can also be used for monitoring at the time of trial operation or operation restart. In this case, since the wafer W as a product is not used, the wafer W is not damaged, and the operation can be smoothly and easily confirmed.

[0044]

According to the method and apparatus for polishing a wafer according to the first and third aspects of the present invention, when the number of remaining unpolished wafers in the wafer storage portion becomes smaller than the number of wafer holding heads. By supplying a dummy wafer of the same shape and the same material as the wafer together with the remaining unpolished wafer to each of the wafer holding heads and polishing the wafer, all the wafers stored in the wafer storage unit are made the same. Can be reliably performed under the above polishing conditions, and the polishing of a large number of wafers can be smoothly continued without interruption.

Further, according to the third aspect of the present invention, by using the dummy wafer in the dummy wafer storage section, the dummy wafer can be used as a monitor for a trial operation or a restart of the operation at the time of starting up the operation of the polishing process. Can be.
Accordingly, since a wafer serving as a product is not used, the wafer is not damaged, and the operation can be smoothly and easily confirmed.

According to the method and apparatus for polishing a wafer according to the second and fourth aspects of the present invention, the original wafer storage section and the dummy wafer storage section are obtained by cleaning and drying the polished wafer and the dummy wafer. By returning to the above, a series of steps accompanying the polishing step can be smoothly performed while taking into account the quality control of the wafer. further,
According to the method of manufacturing a wafer according to claim 5 of the present invention, a predetermined number of wafers are continuously polished under the same conditions, even if a fraction occurs in the polishing step. Thus, a large number of wafers of the same quality can be manufactured smoothly and easily.

[Brief description of the drawings]

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

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view of FIG. 1;

FIG. 4 is a cross-sectional view showing a wafer holding head in a conventional wafer polishing apparatus.

[Explanation of symbols]

 Reference Signs List 10 wafer storage unit 11 dummy wafer storage unit 170 platen 172 head (wafer holding head) W wafer W 'dummy wafer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Adachi 985 Ino-no-ino, Ginya, Ikuno-cho, Asago-gun, Hyogo Pref. AC01 CB01 DA17

Claims (5)

[Claims] A platen having a polishing pad attached to a surface thereof, and a plurality of wafer holding heads holding one surface of a wafer to be polished and bringing the other surface of the wafer into contact with the polishing pad. In a wafer polishing method for polishing the other surface of the wafer with the polishing pad by the relative movement between the wafer holding head and the platen, the wafer is sequentially supplied to each wafer holding head from a wafer storage unit that stores a large number of wafers, While performing the polishing of these wafers, when the remaining unpolished wafers in the wafer storage section are smaller than the number of the wafer holding heads, the same shape and the same material as the wafers together with the remaining unpolished wafers Supplying the dummy wafer to each of the wafer holding heads and polishing the wafer. The polishing method of Doha. 2. The method for polishing a wafer according to claim 1, wherein the wafer and the dummy wafer after polishing are washed and dried and returned to the wafer storage section and the dummy wafer storage section. 3. A platen having a polishing pad attached to a surface thereof, and a plurality of wafer holding heads for holding one surface of a wafer to be polished and for abutting the other surface of the wafer on the polishing pad. In a wafer polishing apparatus for polishing the other surface of a wafer with the polishing pad by a relative movement between a wafer holding head and the platen, a wafer storage section for storing a large number of wafers, and a dummy wafer having the same shape and the same material as the wafer And a transfer means for transferring the wafer and the dummy wafer provided between the wafer storage section and the dummy wafer storage section and each of the wafer holding heads, and for transferring the wafer and the dummy wafer. Wafer polishing equipment. 4. The wafer according to claim 3, wherein a cleaning / drying unit for cleaning and drying the wafer and the dummy wafer is provided between the wafer holding head and the wafer storage unit and the dummy wafer storage unit. Polishing equipment. 5. A method for manufacturing a wafer, comprising manufacturing a wafer by polishing the surface of the wafer using the polishing apparatus according to claim 3.