Cleaning and liquid contact with solids – Apparatus – With plural means for supplying or applying different fluids...
Reexamination Certificate
1998-05-01
2001-09-11
Utech, Benjamin L. (Department: 1765)
Cleaning and liquid contact with solids
Apparatus
With plural means for supplying or applying different fluids...
C134S153000, C134S902000, C015S088200, C015S102000
Reexamination Certificate
active
06286525
ABSTRACT:
BACKGROUND OF THE INVENTION
(1). Field of the Invention
The present invention relates to substrate cleaning apparatus and substrate cleaning methods for cleaning surfaces of substrates such as semiconductor wafers, glass substrates for liquid crystal displays, glass substrates for photomasks and substrates for optical disks. In particular, a surface of such a substrate is cleaned while the substrate is spun, with cleaning devices such as cleaning brushes, high-pressure cleaning nozzles or ultrasonic cleaning nozzles.
(2). Description of the Related Art
A conventional substrate cleaning apparatus of this type, generally, includes one cleaning device supported by one support arm. The one cleaning device supported by the support arm is moved over a surface of a spinning substrate between the spin center and the outer periphery of the substrate to clean the entire surface of the substrate.
Where various cleaning devices such as a cleaning brush, a high-pressure cleaning nozzle and an ultrasonic cleaning nozzle are provided, each cleaning device is supported by a separate support arm. Each support arm (or cleaning device) is separately driven by an individual drive mechanism. A selected one of the cleaning devices is moved over a surface of a spinning substrate between the spin center and the outer periphery of the substrate to clean the entire surface of the substrate.
Conventional apparatus with such constructions have the following drawbacks.
Substrate size has been increasing in recent years, and in the case of semiconductor wafers, for example, 8-inch wafers are giving way to 300 mm wafers. Substrates have a larger turning radius (length from spin center to outer periphery) than before. Consequently, a longer time is now required for one cleaning device to move from the spin center to the outer periphery of a substrate. An extended cleaning time is becoming a matter of concern.
The spin velocity of a substrate is progressively higher toward the outer periphery thereof. When, for example, an entire surface of a substrate is cleaned with the same type of cleaning brushes and with the same conditions, regions adjacent the spin center of the substrate are vulnerable to damage, while peripheral regions may be cleaned insufficiently. Such a tendency is all the more outstanding with large substrates. Thus, in cleaning a surface of a large substrate with cleaning brushes, there has been a desire to clean central regions of the substrate with a soft cleaning brush such as a mohair brush in order to avoid damage, and peripheral regions with a hard cleaning brush such as a PVA brush in order to obtain an excellent cleaning result. Such a requirement may be satisfied with a conventional apparatus only by following a troublesome procedure. That is, the soft cleaning brush is attached to the support arm first to clean central regions of a large substrate. When the central regions have been cleaned, the support arm is moved to a retracted position once, and the soft brush is replaced with the hard one. Subsequently, peripheral regions of the large substrate are cleaned with the hard cleaning brush. This procedure poses a problem of low cleaning efficiency and extended cleaning time.
Where a cleaning process is performed by using various cleaning devices, a conventional apparatus cannot clean a surface of a substrate with the various cleaning devices at a time since the support arms supporting the respective cleaning devices would interfere with one another. Thus, the cleaning devices must be selected successively and driven individually for use. While one cleaning device is engaged in a cleaning operation, the other cleaning devices are kept on standby in retracted positions. All this results in low cleaning efficiency and extended cleaning time.
Moreover, the conventional apparatus has a complicated construction and is costly since a plurality of drive mechanisms are provided for the respective support arms supporting the different cleaning devices.
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 of simple construction which promotes cleaning efficiency and achieves a reduced cleaning time.
The above object is fulfilled, according to the present invention, by an apparatus for cleaning a surface of a substrate, comprising:
a substrate supporting device for supporting the substrate;
a substrate spinning device for spinning the substrate supported by the substrate supporting device;
a cleaning device for cleaning the surface of the substrate;
a support arm for supporting the cleaning device; and
a support arm displacing device for displacing the support arm to move the cleaning device supported by the support arm between a cleaning position and a retracted position;
wherein the support arm supports the cleaning device including a plurality of cleaning devices, the support arm displacing device displacing the support arm to move simultaneously the cleaning devices supported by the support arm between the cleaning position and the retracted position;
the apparatus further comprising a cleaning displacement device for simultaneously moving the cleaning devices supported by the support arm, over the surface of the substrate supported by the substrate supporting device and spun by the substrate spinning device.
In another aspect of the invention, there is provided a method of cleaning a surface of a substrate, comprising the steps of.
placing the substrate in position;
moving a plurality of cleaning devices supported by a support arm from a retracted position to a cleaning position;
spinning the substrate; and
cleaning the surface of the substrate by simultaneously moving the cleaning devices supported by the support arm, over the surface of the substrate in a spin.
According to the above substrate cleaning apparatus and method, a plurality of cleaning devices supported by one support arm are simultaneously moved over a surface to be cleaned of a substrate supported and spun. In this way, the surface of the substrate is cleaned simultaneously by the plurality of cleaning devices to improve cleaning efficiency and shorten cleaning time even for large substrates. Further, compared with a conventional apparatus having a plurality of drive mechanisms for driving a plurality of support arms, respectively, the apparatus according to the present invention can move the plurality of cleaning devices with a reduced number of drive mechanisms. This provides a simplified construction and a cost reduction.
Where the cleaning devices supported by the support arm include one type of cleaning devices, these cleaning devices may share the task of cleaning the surface of the substrate to be cleaned. This feature improves cleaning efficiency and shortens cleaning time even for large substrates.
Where the cleaning devices supported by the support arm include different types of cleaning devices, these cleaning devices may be operated simultaneously to clean the surface of the substrate to be cleaned. The different types of cleaning devices may clean the substrate efficiently to shorten cleaning time.
Where the cleaning devices supported by the support arm include different types of cleaning devices, the cleaning devices may be adapted switchable, separately by type, between a cleaning state and an inoperative state. This construction allows a selection between simultaneous cleaning with the plural types of cleaning devices and separate cleaning with each type of cleaning device. A change from one type of cleaning device to another type for use in cleaning treatment may be made simply by switching each type of cleaning device between cleaning state and inoperative state. Thus, such change may be effected speedily.
Where the cleaning devices supported by the support arm include different types of cleaning devices, the support arm may support a plurality of each different type cleaning devices. Then, the different types of cleaning devices supported by the support arm may be simultaneously operated
Morita Akihiko
Nishimura Joichi
Ohtani Masami
Anderson Matthew
Dainippon Screen Mfg. Co.
Ostrolenk Faber Gerb & Soffen, LLP
Utech Benjamin L.
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