Electric heating – Heating devices – Combined with container – enclosure – or support for material...
Reexamination Certificate
1999-07-20
2001-06-12
Walberg, Teresa (Department: 3742)
Electric heating
Heating devices
Combined with container, enclosure, or support for material...
C219S405000, C392S416000, C118S724000
Reexamination Certificate
active
06246030
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a heat processing method and a heat processing apparatus for heating a substrate, such as an LCD substrate or a semiconductor wafer.
BACKGROUND OF THE INVENTION
Conventionally, in a process for manufacturing a semiconductor device, a series of processes is performed upon the surface of a substrate such as a semiconductor wafer (referred to as a ‘wafer’ hereinafter). That is, a circuit pattern is contracted and exposed upon a photo-resist formed on the substrate's surface using a photo-lithography technique, and then the substrate is developed.
During these coating and developing processes, a wafer is coated with a resist, exposed, and then developed. The wafer is heated (baked) before and after these processes, if necessary. Namely, there are performed so-called dehydration baking for drying the wafer, so-called pre-baking (PREBAKE) for heating and removing the resist solution included in the resist, so-called post-exposure baking (hereinafter referred to as ‘PEB’) performed between exposure and development, post-baking (POBEBAKE) performed after development, and so forth.
A heat processing apparatus performing such heat processing comprises a base disposed in a process container for mounting a wafer and a heat generator (such as a heater) buried inside the base. The heat generator heats to a high temperature (such as 120° C.) to heat the wafer. With the influence of this heat generator, the temperature around the base will also rise to approximately 120° C.
SUMMARY OF THE INVENTION
In a conventional heat processing apparatus, however, no special temperature adjusting means is disposed on the inner side or the ceiling of the process container. Therefore, temperature gradually drops from 120° C. as it gets farther away from the base and nearing the inner side and the ceiling of the process container, resulting in uneven temperature distribution of air inside the process container. Such unevenness of temperature causes convection such as air eddy in the space above the wafer mounted upon the base. When this convection comes in contact with the resist film formed upon the wafer or the developed wafer during heat processing, it may cause a development mark or unevenness in the thickness of the resist film, and decrease the yield rate.
An object of the present invention is to provide a heat processing method and a heat processing apparatus which makes the temperature distribution uniform in the space above the substrate while heat processing.
To solve the above-described problem, a first aspect of the present invention is a heat processing method composing the steps of mounting a substrate on a base disposed in a process container, heating the mounted substrate to a predetermined temperature with a heating means disposed inside the base, supplying a gas pre-heated to said predetermined temperature into the process container, and causing said heated gas to pass through a space above the mounted substrate.
A second aspect of the present invention is a heat processing apparatus for heating a substrate mounted on a base to a predetermined temperature with a heating means disposed inside the base, the base disposed in a process container, the apparatus comprising supplying section having a supply vent and supplying a gas into the process container through the supply vent, and means for pre-heating the gas to the predetermined temperature before supplying the gas into the process container, wherein the supply vent is disposed at one of the bottom and the side of the process container.
A third aspect of the present invention is a heat processing apparatus for heating a substrate mounted on a base to a predetermined temperature with a heating means disposed inside the base, the base disposed in a process container, the apparatus comprising, supplying section having a supply vent and supplying a gas into the process container through the supply vent, and means for pre-heating the gas to the predetermined temperature before supplying the gas into the process container, wherein the supply vent of is disposed around the base.
In the present invention, a gas pre-heated to a predetermined temperature is supplied to the process container, and the heated gas passes through a space above the mounted substrate.
Since the gas heated to a predetermined temperature passes through the space above the mounted substrate while heat processing, temperature distribution is kept uniform in the space above the substrate. Therefore, convection disturbing uniform temperature distribution is prevented, and the desired heat processing may be achieved.
These and other objects and profits of the invention can be easily defined by the following explanations and the accompanied drawings.
REFERENCES:
patent: 4976996 (1990-12-01), Monkowski et al.
patent: 5479874 (1996-01-01), Correa
Fuqua Shawntina
Rader Fishman & Grauer
Tokyo Electron Limited
Walberg Teresa
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