Coating apparatus – Control means responsive to a randomly occurring sensed... – Temperature responsive
Reexamination Certificate
1999-01-29
2001-05-08
Edwards, Laura (Department: 1734)
Coating apparatus
Control means responsive to a randomly occurring sensed...
Temperature responsive
C118S724000, C118S725000, C118S641000, C118S058000, C118S069000
Reexamination Certificate
active
06228171
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a heat processing apparatus such as a heating apparatus and a preheating apparatus to be installed in a semiconductor manufacturing system for manufacturing a semiconductor device.
In a photolithography process for manufacturing a semiconductor device and an LCD, resist is coated on a substrate, and the resultant resist coating film is exposed to light and developed. Such a series of processing is carried out in a coating/developing system. The coating/developing system has heating units such as a prebake unit and a postbake unit. These heating units have a hot plate with a built-in heater of a resistance heating type.
The wafers W are processed in units (lots) each consisting of, e.g., 25 wafers. Each lot is processed under the same recipe (individual processing program). Heating is performed under the conditions such as prebaking temperature and postbaking temperature according to the recipe. The wafers belonging in the same lot are heated under the same conditions.
Then, when one lot is completed and a new lot is subjected to the processing, the recipe is switched to a new recipe, accordingly, so that temperature of the hot plate changes. When the heat processing temperature is allowed to change from a low temperature range to a high temperature range, the temperature of the hot plate can be changed immediately if electric supply to the hot plate is increased. However, the heat processing temperature is allowed to switch from the high temperature range to the low temperature range, the temperature of the hot plate cannot be decreased in a short time. This is because a conventionally used heating unit employs an air cooling method. To be more specifically, the hot plate is cooled by blowing a cold air thereon. Since the hot plate (metal disk of approximately 16 mm thick) has a large heat capacity, it takes a long time to decrease the temperature of the hot plate to a desired temperature, thus lowering a throughput.
To overcome the low throughput, if hot plates are provided so as to correspond to the number of different recipes, the hot plates will occupy a huge space. As a result, the apparatus will increase in size and its control system will be more complicated.
To use a single hot plate for different heat processes, it is possible to consider an apparatus equipped with a hot plate having a refrigerant circulating therein to cool the hot plate in a short time. The apparatus of this type has a problem in that the structure of the hot plate becomes complicated, increasing the manufacturing cost.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a heat processing apparatus capable of decreasing temperature of a hot plate in a short time and in a high throughput without complicating a control system.
The heat processing apparatus according to the present invention has
a heating section having a hot plate for heating a substrate in a heat conduction manner;
refrigeration medium for decreasing temperature of the hot plate in a heat exchange manner by bringing the refrigeration medium in direct or indirect contact with the hot plate;
a refrigeration section for storing the refrigeration medium while cooling;
a transport mechanism for taking out the refrigeration medium from the refrigeration section, transporting the refrigeration medium to the heating section, mounting the refrigeration medium on the hot plate, picking up the refrigeration medium from the hot plate, taking out the refrigeration medium from the heating section, and transporting the refrigeration medium to the refrigeration section;
setting means for setting a heat processing temperature for the substrate; and
a controller for controlling temperature of the hot plate by using the refrigeration medium so as to reach the heat processing temperature set by the setting means.
The heat processing apparatus further comprises a sensor for detecting temperature of the hot plate.
In this case, it is preferable that the controller should control the contact time for the hot plate in contact with the refrigeration medium on the basis of the temperature of the hot plate detected by the sensor and the heat processing temperature determined.
In the case where the refrigeration medium includes a plurality of refrigeration members different in heat capacity, it is preferable that the controller should select one or two refrigeration members from the refrigeration members on the basis of the temperature of the hot plate detected by the sensor and the heat processing temperature determined, and that the transport mechanism should transport the one or two refrigeration members selected, from the refrigeration section to the heating section, mounting the one or two refrigeration members on the hot plate to allow the one or two refrigeration members in contact with the hot plate for the contact time, and transporting the one or two refrigeration members from the heating section to refrigeration section.
In the case where the refrigeration medium includes a plurality of refrigeration members different in heat capacity, the refrigeration members may be different in thickness and in material.
Furthermore, it is preferable that the controller should control temperature for cooling the refrigeration medium in the refrigeration section on the basis of the temperature of the hot plate detected by the sensor and the heat processing temperature determined.
It is further preferable that the refrigeration medium has a plan-view shape substantially the same as that of the substrate.
It is still preferable that the refrigeration medium should be made of a material containing no harmful ingredients to not only the substrate but also a film formed on the substrate.
Incidentally, it is preferable that the transporting mechanism should place the refrigeration medium on the hot plate so as to cover an area of the hot plate at which the substrate comes in contact with the hot plate or near which the substrate is placed so as to face the hot plate.
Furthermore, the refrigeration section has
a plurality of cooling plates each cooling the corresponding refrigeration medium refrigerant in a heat conduction manner,
a lift mechanism having a plurality of pins pushing up the refrigeration medium from each of the cooling plates; and
a plurality of compartments each surrounding the corresponding cooling plate.
The refrigeration section has
a cooling plate for collectively cooling the refrigeration medium stacked one upon the other in multiple stages,
a lift mechanism having a plurality of pins for pushing up at least one of the refrigeration medium from the cooling plate, and
a compartment surrounding the cooling plate.
In this case, the pins may be arranged on a common concentric circle in the same plane.
Alternatively, the pins are arranged by being divided on two concentric circles in the same plane.
Note that it is preferable that a high purity silicon (Si), silica glass (SiO
2
) and silicon carbide (SiC) may be used as the refrigeration medium. This is because they are stable even in a high temperature range and no possibility of contaminating a silicon wafer.
The refrigeration medium desirably has substantially the same plan-view shape as the substrate. In this case, the refrigeration medium refrigerants can be designed so as to have various heat capacities by changing thickness and material of the refrigeration medium.
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: 4886571 (1989-12-01), Suzuki et al.
patent: 5817178 (1998-10-01), Mita et al.
patent: 1-168026 (1989-07-01), None
Edwards Laura
Rader Fishman & Grauer
Tokyo Electron Ltd.
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