JP2607479B2 - Scrubber for recycling mirror-surface wafers for foreign substance inspection - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scrubber for regenerating a mirror-surface wafer used for foreign substance management in a semiconductor wafer processing process.

[Conventional technology]

In a semiconductor wafer processing process, foreign matter in the process has a great effect on the manufacturing yield. Therefore, before executing the process, a foreign substance test using a mirror-finished wafer as a dummy wafer is performed, and various measures are taken based on the test results. In the test using the mirror-surface wafer, the mirror-surface wafer that has been used once is cleaned with a scrubber in order to reuse the mirror-surface wafer.

Conventionally, this type of scrubber has a configuration including a high-pressure nozzle for injecting cleaning water at high pressure and a mohair brush rotated on a mirror-finished wafer, for brush rinse, brush scrub, high-pressure scrub and spin drying. Cleaning is performed according to the procedure. Particularly, in brush scrubbing, a mohair brush is rotated to brush scour the surface of a mirror-finished wafer, and in high-pressure scrubbing, scrubbing is performed by projecting cleaning water ejected from a high-pressure nozzle onto the entire surface of a mirror-finished wafer. .

Japanese Utility Model Application Laid-Open No. 51-84371 discloses a semiconductor substrate cleaning apparatus characterized in that the surface of a semiconductor substrate is mechanically brushed and cleaned with a rotating brush. However, Japanese Utility Model Application Laid-Open No. 51-84371 discloses brushing the semiconductor substrate while spraying the cleaning liquid, and does not disclose a configuration in which the brush does not contact the semiconductor substrate when the cleaning liquid is sprayed.

[Problems to be solved by the invention]

In such a conventional scrub, a relatively large foreign substance caught in the mohair brush during the brush scrub comes into contact with the wafer surface, so that a scratch is easily generated. In addition, since the amount of high-pressure cleaning water sprayed from the high-pressure nozzle is relatively small, it is difficult to completely remove fine foreign matters from the mirror-finished wafer surface. For this reason, it is difficult to regenerate the mirror-finished wafer due to the remaining foreign matters and the generation of scratches, which causes an increase in manufacturing cost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer scrubber capable of effectively cleaning a mirror-finished wafer, preventing the generation of foreign particles and scratches on the wafer, and reliably reproducing the wafer.

[Means for solving the problem]

The wafer scrubber of the present invention is provided with a low pressure nozzle that sprays cleaning water at a low pressure in parallel with the high pressure nozzle, and furthermore, this low pressure nozzle is configured to be able to operate before the brush scrub and after the high pressure scrub, respectively. ing.

[Action]

According to this configuration, relatively large foreign matter can be washed away by projecting the low-pressure cleaning water sprayed from the low pressure nozzle onto the entire surface of the mirror wafer before the brush slab. The occurrence of scratches can be prevented without being involved. Further, by flowing the cleaning water collected from the low pressure nozzle to the mirror-finished wafer after the high pressure scrub, fine foreign matters can be washed away, and the foreign matters can be surely removed.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a main part of one embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA, and FIGS. 3 and 4 are a plan view and a front view of the entire apparatus.

In these figures, the scrubber is a scrubber 1
A loading unit 2 for loading and unloading a wafer into and from the scrub unit 1; and a control unit 3 for operating the scrub unit 1.

As shown in detail in FIGS. 1 and 2, the scrub section 1 has a wafer chuck 11 on which a mirror-surface wafer W is placed and which can be rotated at a high speed, and a brush unit 11A and a brush chuck 11A opposed thereto. And a cleaning unit 1B.

The brush unit 1A has a mohair brush 14 attached to the tip of an elevating arm 13 which is moved up and down by an elevating rotor 12. This mohair brush 14 is rotated in a direction perpendicular to the mirror wafer W by a chain 12a. . The elevating rotor 12 and the arm 13 are connected to a telescopic rod 15a of a horizontally arranged cylinder 15, and the cylinder 15 can reciprocate in the left-right direction in FIG.

Further, the cleaning unit 1B has a cleaning nozzle head 18 for spraying cleaning water attached to a tip of an L-shaped arm 17 provided integrally with a movable rod 16a of a cylinder 16, and the mohair brush 14 Is reciprocated in the same direction. The washing nozzle head 18 is provided with a high pressure nozzle 18a for ejecting washing water at high pressure and a low pressure nozzle 18b for ejecting washing water at low pressure. Here, the injection pressure of the high pressure nozzle 18a is set to 200 kg / cm ² , and the injection pressure of the low pressure nozzle 18b is set to 6 kg / cm ² .

 Reference numeral 19 denotes a collecting pan for collecting pure water for brush rinsing.

The loading unit 2 sends out the mirror wafer W set in the loader 21 to the pre-alignment unit 22,
And, this is transferred to the scribing unit 1 by the handler 23. The handler 23 can also take out the wafer after the scrub is completed from the scrub section 1 to the unloader 24.

The control unit 3 includes a control power supply 31, a panel 32 for setting operation timings of the scrubbing unit 1, a rotation speed and a time of the wafer chuck 32, a high-pressure pure water generating unit 33 for high-pressure scrub, and a pressurizing pressure of the brush unit. An adjustment gauge 34 and a forced fan 35 for discharging water mist generated during spin drying together with the drying nitrogen gas are provided.

According to the scrubber having the above structure, the wafer can be scrubbed in the step of FIG.

First, when the mirror-finished wafer W is set on the scrub section 1 by the loader 21 and the handler 23, the wafer chuck 11
Rotated at 300rpm. At this time, the low pressure nozzle
Low pressure pure water is sprayed onto the wafer surface from 18b, and the wafer is pre-cleaned with a large amount of pure water flowing over the wafer surface. As a result, relatively large foreign matter can be washed away from the wafer surface.

Meanwhile, on the other hand, pure water is supplied while rotating the mohair brush 14 to perform brush rinsing for about 5 hours.

The mohair brush 14 is lowered by the elevating rotor 12 and the elevating arm 13 to contact the surface of the wafer W, and performs a brush scrub for about 20 seconds by its rotation operation. As a result, fine foreign matter adhering to the wafer surface is peeled off from the wafer surface.

Then, the pure pressure finely squeezed from the high pressure nozzle 18a is sprayed onto the wafer surface at a pressure of about 120 kg / cm ² , and the nozzle 18a
Is reciprocated about the entire surface of the wafer for about 30 seconds. Then, about 1 liter of pure water was again applied at low pressure from the low pressure nozzle 18b.
Post cleaning is performed by spraying the entire surface of the wafer for 5 seconds, and fine foreign substances remaining on the wafer surface are washed away. Then, the wafer is rotated by the wafer chuck 11 at 7000 rpm for 20 seconds to perform spin drying.

Thus, the scrub process is completed, and the wafer is stored in a required cassette by the operation of the handler 23 and the unloader 24, and the entire process is completed.

Therefore, according to this scrub, a pre-cleaning step is added before the brush scrub, and a post-cleaning step is performed after the high pressure scrub, as can be seen from the conventional step shown in FIG. 5 (b). Has been added.

For this reason, large foreign substances existing on the wafer surface can be reliably removed by pre-cleaning during brush scrubbing, so that scratches caused by the large foreign substances being caught in the brush do not occur. Further, even after the high pressure scrub, the fine foreign matter still remaining on the wafer surface can be surely removed by the post-cleaning, so that the fine foreign matter does not remain. Thereby, extremely good cleaning can be realized, and the reuse efficiency of the mirror surface wafer can be increased.

〔The invention's effect〕

As described above, the present invention provides a low pressure nozzle that injects cleaning water at a low pressure in parallel with the high pressure nozzle, and further operates the low pressure nozzle before the brush scrub and after the high pressure scrub to perform pre-cleaning and cleaning. It is configured to be able to perform post-cleaning, so that a pre-cleaning process using a low-pressure nozzle can prevent scratches from occurring during scrubbing, in which relatively large foreign substances on the mirror-surfaced wafer have been removed. Fine foreign matters remaining on the surface can be washed away, thereby making it possible to reliably prevent scratches and foreign matters from remaining on the wafer, and improve the scrubbing effect of the wafer.

[Brief description of the drawings]

FIG. 1 is a plan view of a main portion of the scrubber of the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, FIG. 3 is a plan view of the overall configuration of the scrubber of the present invention, and FIG. FIG. 5 (a) is a cleaning process diagram in the present invention, FIG. 5 (b)
FIG. 2 is a conventional cleaning step diagram. 1 ... Scrubbing section, 1A ... Brush unit, 1B ... Cleaning unit, 2 ... Loading section, 3 ... Control section, 11 ...
… Wafer chuck, 12… Lift rotor, 13… Lift arm, 14… Mohair brush, 15… Cylinder, 16… Cylinder, 17… Arm, 18… Cleaning nozzle head, 18 a…
… High pressure nozzle, 18b …… Low pressure nozzle, 19 …… Collection tray, 21 …… Loader, 22 …… Prealignment unit, 23 …… Handler, 24 …… Unloader, 31 …… Control power, 32 …… Setting panel, 33 High pressure pure water generator, 34 Pressure adjusting gauge, 35 Force fan, W Mirror wafer.

Continuation of the front page (72) Inventor Shigeo Shimomura 3300 Hayano, Mobara-shi Inside the Mobara Plant of Hitachi, Ltd. (56) References JP-A-57-102024 (JP, A) JP-A-61-26226 (JP, A JP-A-61-18958 (JP, A) JP-A-60-194335 (JP, U)

Claims (1)

(57) [Claims] 1. A wafer chuck for mounting a mirror-surface wafer for foreign substance inspection, a low-pressure cleaning water nozzle for spraying cleaning water, a brush for brush-scrubbing the mirror-surface wafer, and a cleaning water jet from the low-pressure cleaning water nozzle. A high-pressure washing water nozzle for injecting washing water at high pressure, wherein the brush and the mirror-finished wafer are washed with the low-pressure washing water nozzle before the brush scrubbing the mirror-finished wafer with the brush, and the brush scrubbing step is performed. Then, after the step of cleaning the mirror-finished wafer with the cleaning water sprayed from the high-pressure cleaning water nozzle and cleaning with the high-pressure cleaning water nozzle, the low-pressure cleaning water nozzle can be operated to clean the mirror-finished wafer. A scrubber for regenerating a mirror-surface wafer for foreign substance inspection, characterized in that the scrubber is configured as described above.