Cleaning and liquid contact with solids – Apparatus – Automatic controls
Reexamination Certificate
1998-10-06
2001-07-17
Stinson, Frankie L. (Department: 1743)
Cleaning and liquid contact with solids
Apparatus
Automatic controls
C134S05600D, C134S0580DL, C134S113000, C134S902000, C134S181000
Reexamination Certificate
active
06260562
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to substrate cleaning apparatus and methods for supplying a cleaning liquid from a nozzle to and cleaning substrates such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, substrates for optical disks and the like. More particularly, the invention relates to a technique of performing a cleaning process while moving a nozzle so that a cleaning liquid supply position on a surface of a substrate moves at least between center and edge of the substrate.
(2) Description of the Related Art
A conventional substrate cleaning apparatus of the type noted above includes, for example, a spin support mechanism for supporting and spinning a substrate, a jet nozzle for discharging a high-pressure jet of cleaning liquid under a fixed pressure, and a moving mechanism for moving the nozzle so that a cleaning liquid supply position on the surface of the substrate moves at a fixed speed at least between center and edge of the substrate.
This apparatus supplies the cleaning liquid over the entire surface of the substrate by moving the nozzle while spinning the substrate, so that the cleaning liquid supply position on the surface of the substrate moves at least between center and edge of the substrate. In this way, the substrate surface is cleaned with particles of dust and the like removed therefrom.
The cleaning liquid discharge pressure is one of the cleaning conditions that greatly influence the effect of cleaning. Thus, the discharge pressure is varied for each lot of substrates with different degrees of particle adhesion, for each type of substrate or for each individual substrate.
The above conventional apparatus has the following drawback.
The substrate in a spin moves, in a central region thereof, at low speed relative to the nozzle, and at increasing speed toward the edge. The central region of the substrate moving at low relative speed may undergo an excessive impact of the cleaning liquid. Generally, the cleaning liquid discharge pressure which is one of the cleaning conditions is set to achieve an optimal cleaning result for the central region of the substrate. With the discharge pressure selected to suit the central region, edge regions of the substrate moving at high relative speed cannot be cleaned sufficiently. Such uneven cleaning results have adverse effects on subsequent substrate treatment.
A different substrate cleaning apparatus includes, instead of the above jet nozzle, a nozzle for discharging a cleaning liquid with ultrasonic vibration of a fixed frequency. This apparatus supplies the cleaning liquid with ultrasonic vibration over the entire surface of a substrate by reciprocating the nozzle over the substrate surface while spinning the substrate at a fixed speed. In this way, the substrate surface is cleaned with particles of dust and the like removed therefrom by ultrasonic vibration.
An ultrasonic frequency or output applied to the cleaning liquid is one of the cleaning conditions that greatly influence the effect of cleaning. Thus, the ultrasonic frequency or output is varied for each lot of substrates with different degrees of particle adhesion, for each type of substrate or for each individual substrate.
This conventional apparatus also has the following drawback.
The substrate moves, in a central region thereof, at low speed relative to the nozzle, and at increasing speed toward the edge. The central region of the substrate moving at low relative speed may undergo an excessive impact of the ultrasonic vibration applied to the cleaning liquid. Generally, the ultrasonic output which is one of the cleaning conditions is set to achieve an optimal cleaning result for the central region of the substrate. With the ultrasonic output selected to suit the central region, edge regions of the substrate moving at high relative speed cannot be cleaned sufficiently. Such uneven cleaning results have adverse effects on subsequent substrate treatment.
SUMMARY OF THE INVENTION
The present invention has been made having regard to the state of the art noted above, and its object is to provide a substrate cleaning apparatus and method for uniformly cleaning an entire surface of a substrate by varying cleaning conditions according to a cleaning liquid supply position moving over the substrate surface.
The above object is fulfilled, according to the present invention, by a substrate cleaning apparatus comprising:
a spin support device for supporting and spinning a substrate;
a nozzle for discharging a cleaning liquid with a given cleaning condition from a discharge opening;
a moving device for moving the nozzle over a surface of the substrate such that a supply position in which the cleaning liquid discharged from the nozzle is supplied moves at least between center and edge of the substrate;
a cleaning condition adjusting device for adjusting the cleaning condition; and
a control device for controlling the cleaning condition adjusting device to vary the cleaning condition according to the supply position movable over the surface of the substrate.
The substrate spun by the spin support device has a moving speed relative to the nozzle which varies from position to position on the substrate surface. However, the control device controls the cleaning condition adjusting device to vary the cleaning condition according to the cleaning liquid supply position on the substrate surface, thereby to assure a constant level of cleaning. Consequently, the entire surface of the substrate is cleaned uniformly.
Preferably, the cleaning condition is a discharge pressure of the cleaning liquid discharged from the discharge opening of the nozzle, the cleaning condition adjusting device is a discharge pressure adjusting device for adjusting the discharge pressure, and the control device is operable for controlling the discharge pressure adjusting device to adjust the discharge pressure according to the supply position movable over the surface of the substrate.
The control device controls the discharge pressure adjusting device to adjust the discharge pressure according to the cleaning liquid supply position movable over the substrate surface. Consequently, the same level of cleaning is obtained for any position on the substrate surface.
It is also preferred that the cleaning condition is an ultrasonic output applied to the cleaning liquid discharged from the nozzle, the cleaning condition adjusting device is an ultrasonic output adjusting device for adjusting the ultrasonic output, and the control device is operable for controlling the ultrasonic output adjusting device to adjust the ultrasonic output according to the supply position movable over the surface of the substrate.
The control device controls the ultrasonic output adjusting device to adjust the ultrasonic output applied to the cleaning liquid according to the cleaning liquid supply position. Thus, a constant level of cleaning is obtained over the entire surface of the substrate spun by the spin support device. The ultrasonic output may be varied to fix the level of cleaning, thereby to clean the entire surface of the substrate uniformly with relative ease.
Preferably, the substrate cleaning apparatus according to the invention further comprises a position detecting device for detecting the supply position movable over the surface of the substrate, the control device being operable for controlling the cleaning condition adjusting device based on the supply position detected by the position detecting device.
The control device controls the cleaning condition adjusting device based on the cleaning liquid supply position over the substrate surface detected by the position detecting device. Thus, the cleaning condition may be adjusted according to the cleaning liquid supply position accurately detected, to ensure a constant level of cleaning. Consequently, the entire surface of the substrate is cleaned uniformly with increased assurance.
REFERENCES:
patent: 4564280 (1986-01-01), Fukuda
patent: 5364474 (1994-11-01),
Morinishi Kenya
Morita Akihiko
Nishimura Joichi
Ohtani Masami
Arent Fox Kintner & Plotkin & Kahn, PLLC
Dainippon Screen Mfg. Co,. Ltd.
Stinson Frankie L.
LandOfFree
Substrate cleaning apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Substrate cleaning apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Substrate cleaning apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2515082