Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With microwave gas energizing means
Reexamination Certificate
1998-08-26
2001-05-29
Osele, Mark A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With microwave gas energizing means
C156S583200, C134S172000, C216S092000
Reexamination Certificate
active
06238511
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing method and apparatus for use in removing a coating film (a photoresist film and an anti-reflective coating film) formed on a surface of an LCD (liquid crystal display) substrate or on a layer (semiconductor layer, insulating layer, electrode layer) formed on the substrate, from peripheral portion thereof.
In an LCD manufacturing process, a photolithographic technology is usually employed similarly in a manufacturing process for a semiconductor device. In the photolithographic process for LCD, a resist coating film is first formed on a glass substrate. The resultant substrate is pattern-exposed and developed. Thereafter, a semiconductor layer, an insulating layer, and an electrode layer formed on the substrate are selectively etched to obtain an ITO (Indium Tin Oxide) thin film and an electrode pattern.
When a resist solution is applied onto the LCD substrate, it forms a film. Although it is uniform in thickness immediately after the coating, the resist solution rises up at the peripheral portion of the substrate by the influence of the surface tension after rotation is terminated and centrifugal force is no longer applied to the substrate, or with the passage of time. Furthermore, the resist solution spreads and reaches a lower peripheral portion of the substrate G to form an undesirable film. When the non-uniform film (thick in the periphery of the substrate G) is thus formed, the peripheral resist film is not completely removed and left even at the time an integrated circuit pattern is developed. The remaining resist will be removed during the step of transporting the substrate G, leading into particles.
Then, after the resist solution is applied onto the substrate G, the substrate G is transported to a peripheral resist removing mechanism to remove the resist coating film from the peripheral portion of the substrate G. Such a resist removing mechanism is disclosed in U.S. Pat. Nos. 5,718,763 and 5,695,817.
In the meantime, to dissolve the resist solution, a solvent such as n-butyl acetate (NBA) or methylethyl ketone (MEK) has been conventionally used. However, a large amount of the solvent leaks out into the working atmosphere in a factory for producing the LCD substrate in quantity. Under the circumstances, a so-called “safe solvent” having little negative effect on a human body, has been increasingly used. As an example of the safe solvent, an organic solvent such as OK73 thinner (manufactured by TOKYO OHKA KOGYO CO., LTD) may be used. OK73 thinner contains propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) in a ratio of 3:7. As another example, 2-heptanon may be mentioned. 2-heptanon is a less-volatile solvent having a high boiling point (e.g., 140° C. or more).
Of these safe solvents, however, OK 73 thinner has a poorer solubility of the resist film than conventionally employed solvents. It is therefore difficult to remove the resist coating film completely from the peripheral portion of the substrate by a method employing the conventionally-employed solvent.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a substrate processing method and apparatus capable of removing a coating film from a peripheral portion of the substrate swiftly and securely even if a solvent (safe solvent) poor in solubility is used.
According to the present invention, there is provided a method of processing a substrate for removing a coating film from the substrate by dissolving the coating film with a solvent, comprising the steps of:
(a) supplying a solvent independently to each of peripheral portions of an upper surface side and a lower surface side of the substrate; and
(b) supplying the solvent to the peripheral portion of the lower surface side of the substrate in an amount lower than the solvent supplied to the peripheral portion of the lower surface side in the step (a) or lower than that supplied to the peripheral portion of the upper surface side in this step (b); or terminating a supply of the solvent.
In the step (b), it is desirable that the first and second nozzles be moved along the peripheral portion of the substrate while supplying the solvent, and that the scanning speeds of the first and second nozzles be reduced as the first and second nozzles approach a corner portion of the substrate.
It is also desirable, in the step (b), that the first and second nozzles be moved along the peripheral portion of the substrate while supplying the solvent, and that the solvent supply amounts from the first and second nozzles be increased as the first and second nozzles approach a corner portion of the substrate.
Furthermore, it is desirable that a total amount of the solvent supplied from the first and second nozzles in the step (b) be smaller than a total amount of the solvent supplied form the first and second nozzles in the step (a).
It is desirable, in the step (a), that the solvent be supplied from the first and second nozzles at a rate of at least 30 cc/minute, and that the flow route thereof on the substrate along a side of the substrate be 50 mm or more in length.
It is preferred to use an organic solvent containing propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) in a ratio of 3:7, as the solvent. An ether-based organic solvent such as 2-heptanon may be used.
An apparatus for processing a substrate according to the present invention comprises
a table for adsorbing and holding a substrate with a coating surface upward;
a solvent supply mechanism for supplying a solvent, independently to each of peripheral portions of the upper surface side and a lower surface side of the substrate mounted on the table; and
a control mechanism for controlling the solvent supply mechanism to selectively supply the solvent either to both upper surface side and lower surface side or only to the upper surface side.
A method of processing a substrate according to the present invention comprises the steps of:
(A) supplying a solvent from a solvent supply mechanism while sucking the solvent by a suction-discharge mechanism to relatively move the solvent supply mechanism, the suction-discharge mechanism, and the substrate, thereby permitting the solvent supply mechanism and the suction-discharge mechanism to come closer to or go away from a peripheral portion of the substrate;
(B) discharging the solvent and a dissolved matter by the suction-discharging mechanism while supplying the solvent to the peripheral portion of the substrate by the solvent supply mechanism.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 5688411 (1997-11-01), Kutsuzawa et al.
patent: 5695817 (1997-12-01), Tateyama et al.
patent: 5718763 (1998-02-01), Tateyama et al.
patent: 5904164 (1999-05-01), Wagner et al.
patent: 5952050 (1999-09-01), Doan
patent: 5993552 (1999-11-01), Tsukumoto et al.
patent: 6062288 (2000-05-01), Tateyama
patent: 6079428 (2000-05-01), Anai
patent: 2-157763 (1990-06-01), None
patent: 5-114555 (1993-05-01), None
Kawasaki Tetsu
Sada Tetsuya
Sakai Mitsuhiro
Tsukamoto Takeshi
Osele Mark A.
Rader Fishman & Grauer
Tokyo Electron Limited
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