JPH06181173A - Heating system - Google Patents

Abstract

PURPOSE:To vary treating temperature of wafer while sustaining the temperature of a hot plate constant. CONSTITUTION:A wafer 1 is supported on proximity pins 3 and a hot plate 2 is disposed on the rear surface of the wafer 1. The proximity pins 3 are moved up and down by means of a pulley 6, a timing belt 8, and a servo motor 7. Consequently, the gap(proximity gap) between the wafer and the hot plate can be varied and thereby treating temperature of wafer can be varied while sustaining the temperature of hot plate constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor integrated circuit manufacturing apparatus, and more particularly to a heat treatment apparatus for baking a wafer after photoresist application, exposure, or development in a photolithography process.

[0002]

2. Description of the Related Art In a conventional heating device, a wafer 1 is supported on a hot plate 2 via a proximity pin 3 as shown in FIG. 5, and a heater 4, a temperature sensor 5, and a temperature control circuit 9 are used to make the hot plate. 2 was temperature-controlled.

To adjust the temperature of the hot plate 2, a method of changing the baking processing temperature of the wafer by changing the amount of electric power applied to the heater in the hot plate, as disclosed in Japanese Patent Laid-Open No. 3-169367, or an actual flat plate 2 is disclosed. As disclosed in Japanese Laid-Open Patent Publication No. 94251, a method of changing the baking processing temperature of the wafer by changing the position of the heater in the hot plate is adopted.

However, none of these methods aims to change the baking temperature during the continuous processing of one wafer, and always sets the temperature at a predetermined temperature in advance. It is assumed that the treatment is performed while keeping the temperature constant.

Therefore, when it is necessary to increase the temperature of the baking process stepwise, a number of hot plates corresponding to the number of steps are provided, and different temperatures are set for each hot plate. Every time, the operation of transferring one wafer to another hot plate having a high temperature during the baking process is required.

Further, depending on the type and film thickness of the photoresist on the wafer to be baked, it is necessary to lower the temperature rising rate of the wafer during the baking process. On the hot plate, the proximity pin is fixed, so changing the heating rate required converting the proximity pin to a different height or adjusting the height.

For this reason, when different baking processing conditions are used, a preliminary work of changing the proximity gap is performed each time the conditions are changed, or hot plates are prepared for each kind of baking processing conditions. Each time, a method of selecting and using a hot plate suitable for the required baking treatment condition has been adopted.

[0008]

[Problems to be Solved by the Invention]
The following problems occur when the baking processing temperature of the wafer is changed on the way by using the method described in Japanese Patent Publication No. 7 and Japanese Utility Model Application Laid-Open No. 2-94251.

First, since the hot plate has a large heat capacity, it is difficult to raise the temperature in a short time. Further, when this problem is dealt with by increasing the amount of electric power of the heater, it is difficult to control the temperature to a constant temperature immediately after reaching a predetermined temperature, and the temperature rises too much to some extent. The phenomenon of shooting occurs remarkably.

Secondly, even if the same temperature processing as the above-described multi-step bake can be performed with one hop rate, when the plurality of wafers are continuously processed, the next wafer is processed. It is necessary to return to the initial temperature before, but in this case too, it is difficult to cool it in a short time due to the large heat capacity of the hot plate, and it takes a considerable waiting time to recover to the initial temperature. And

For these reasons, the current heating apparatus has dealt with the problem by providing a plurality of hot plates in one unit. However, due to the recent sophistication of the manufacturing process of semiconductor integrated circuits, it is possible to deal with the baking processing of wafers. Demands are becoming more stringent, and it is becoming necessary to install more heating devices with more hot plates and increase the number of devices to handle this,
This causes an increase in equipment costs in the construction of semiconductor manufacturing lines and an increase in clean room construction costs due to an increase in equipment installation area.

An object of the present invention is to provide a heating device capable of changing the processing temperature of a wafer while keeping the temperature of the hot plate constant.

[0013]

In order to achieve the above object, a heating device according to the present invention is a heating device having a hot plate, a proximity pin, and a height adjusting mechanism, and the hot plate is fixed. Temperature adjusted to the temperature,
It heats the wafer, and the proximity pins
The wafer is supported at a position heated by the hot plate and is moved up and down with respect to the hot plate, and the height adjusting mechanism changes the height of the proximity pin with respect to the hot plate.

The height adjusting mechanism is provided with a thermometer for measuring the surface temperature of the wafer, and controls the movement of the proximity pin based on the measured value of the thermometer.

[0015]

It is possible to change the proximity gap during the wafer baking process. If the proximity gap is increased while the hot plate temperature is kept constant, the baking temperature of the wafer decreases,
On the contrary, if the proximity gap is made small, it becomes possible to raise the wafer baking temperature.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic view showing a heating apparatus according to Embodiment 1 of the present invention.

In FIG. 1, the wafer 1 is supported on proximity pins 3, and a hot plate 2 is arranged on the lower surface of the wafer 1. A heater 4 and a temperature sensor 5 are incorporated inside the hot plate 2 to keep the hot plate 2 at a constant temperature.

The lower part of the proximity pin 3 is threaded, and the pulley 6 fitted therein is rotated to move the proximity pin 3 up and down. The pulley 6 is connected to the servomotor 7 via a timing belt 8, and thereby the proximity pin 3 can be automatically moved up and down by electric control from the outside.

FIG. 2 shows the relationship between the proximity gap and the wafer temperature. Here, the proximity gap indicates the distance between the wafer 1 and the hot plate 2. It can be seen from FIG. 2 that the wafer temperature decreases as the proximity gap increases. Therefore, as shown in FIG. 3, it is possible to gradually raise the temperature of the wafer by gradually decreasing the proximity gap during the baking processing time of the wafer.

In the first embodiment, the rate of rise of the wafer temperature can be increased by increasing the rate of fall of the proximity pins. Furthermore, by changing the value of the proximity gap, the processing temperature of the wafer can be easily changed.

(Second Embodiment) FIG. 4 is a schematic view showing a second embodiment of the present invention.

The second embodiment is different from the first embodiment in that a radiation thermometer 9 for indirectly measuring the surface temperature of the wafer is installed above the wafer.

The temperature of the wafer being baked is measured in real time by the radiation thermometer 9, and this temperature signal is fed back to the motor control circuit 10 by the arithmetic processing unit 12 to reduce the difference from the desired wafer temperature. To control the proximity gap. According to this embodiment,
Compared with the first embodiment, there is an advantage that a more accurate baking process can be performed.

[0025]

As described above, according to the present invention, by changing the proximity gap during the baking processing of the wafer, the processing temperature of the wafer can be easily changed while keeping the temperature of the hot plate constant. be able to.

In the prior art, when it is desired to change the processing temperature of a wafer on the way, a plurality of hot plates each having a different temperature are prepared and one wafer is sequentially processed during processing. Although it is necessary to carry out an operation such as loading and replacing, in the present invention, since the same processing can be realized by one hot plate, the cost of the apparatus and the installation area can be reduced, and the wafer during processing can be further reduced. It is possible to shorten the processing time by eliminating the need for the transfer operation.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a proximity gap and a wafer temperature.

FIG. 3 is a diagram showing a temperature change of a wafer when a proximity gap is changed during wafer processing.

FIG. 4 is a schematic diagram showing a second embodiment of the present invention.

FIG. 5 is a schematic view showing a conventional heating device.

[Explanation of symbols]

 1 Wafer 2 Hot Plate 3 Proximity Pin 4 Heater 5 Temperature Sensor 6 Pulley 7 Servo Motor 8 Timing Belt 9 Temperature Control Circuit 10 Motor Control Circuit 11 Radiation Thermometer 12 Calculation Processor

Claims (2)

[Claims] 1. A heating device having a hot plate, a proximity pin, and a height adjusting mechanism, wherein the hot plate is for adjusting the temperature to a constant temperature to heat the wafer, and the proximity pin is for The wafer is supported at a position heated by the hot plate and is moved up and down with respect to the hot plate. The height adjusting mechanism is to change the height of the proximity pin with respect to the hot plate. Heating device. 2. The height adjusting mechanism includes a thermometer for measuring the surface temperature of the wafer, and controls the movement of the proximity pin based on the measurement value of the thermometer. The heating device according to 1.