JPH05299333A - Bake processing equipment - Google Patents

Abstract

PURPOSE:To improve temperature stability of proximity bake in the bake processing of a wafer in a photolithography process. CONSTITUTION:The radiation heat of a water 1 which is mounted on a hot plate 2 via proximity pins 3 is detected with a sensor 5. On the basis of the output signal of the sensor 5, the surface temperature of the wafer 1 is calculated with an operation processing part 6. On the basis of the temperature output signal, the output of a heater 4 is so controlled with a temperature control part 7 that the wafer surface temperature by heating with a heater 4 becomes equal to a previously set temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for baking a semiconductor integrated circuit in a manufacturing process, especially after applying a photoresist in a photolithography process, after exposing or after developing.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional baking apparatus places a semiconductor substrate (hereinafter referred to as a wafer) 1 on a hot plate 2 having a heater 4 and a temperature detecting sensor 8 incorporated therein, and a semiconductor substrate (hereinafter referred to as a wafer) 1 is mounted on the hot plate 2. The temperature of the heater 4 is controlled by the temperature controller 7 based on the output signal, and the wafer 1 is baked at a predetermined temperature.

Conventionally, a method of directly placing a wafer on a hot plate (so-called contact bake) has been generally used. In this method, however, the back surface of the wafer adheres to the front surface of the hot plate, so that the back surface of the wafer is exposed. The adhesion of dust is a problem.

For this reason, recently, a so-called proximity pin 3 has been provided for performing a baking process with a clearance of about 0.1 to 0.2 mm provided without bringing the wafer and the hot plate into close contact with each other, and the wafer 1 is placed thereon. It is a method of carrying out a baking process by placing.

[0005]

In the contact bake, the wafer temperature is the same as the surface temperature of the hot plate because the hot plate and the wafer are in close contact. However, in the proximity bake, the wafer is in close contact with the hot plate. Since the contact bake is heat conduction to the wafer because it does not exist, the proximity bake is heat transfer, so the efficiency is poor, and as shown in FIG. 4, the distance between the hot plate and the wafer ( There is a phenomenon that the surface temperature of the wafer becomes lower as the (proximity gap) becomes larger.

The proximity gap is apt to change easily due to dust or the like adhering to the proximity pin, and the proximity gap is apt to change due to the influence of the warp of the wafer itself.

For the above reasons, the proximity bake has a problem that it is difficult to keep the wafer surface temperature constant as compared with the contact bake.

An object of the present invention is to provide a bake processing apparatus that keeps the wafer surface temperature constant in a proximity bake.

[0009]

In order to achieve the above object, a baking apparatus according to the present invention comprises a radiant heat sensor,
A radiant heat sensor, comprising a calculation processing section and a temperature control section, and placing a semiconductor substrate on a hot plate heated by a heater via a proximity pin to perform a baking treatment on the substrate. Is to detect the radiant heat from the semiconductor substrate heated by the hot plate, the arithmetic processing unit is to calculate the surface temperature of the semiconductor substrate based on the output signal of the radiant heat sensor, the temperature control unit,
Based on the temperature output signal from the arithmetic processing unit, the output of the heater for heating the hot plate is controlled to an output value where the substrate surface temperature reaches the set temperature.

[0010]

[Function] The radiant heat from the wafer is detected by the sensor on the upper part of the wafer, the surface temperature of the wafer is calculated from the output signal of this sensor, and the temperature is preset based on the temperature output signal after the calculation processing. Controls the heater output.

When the proximity gap changes, the conventional technique changes the surface temperature of the wafer, making it impossible to perform a baking process at a predetermined temperature. On the other hand, in the baking apparatus of the present invention, A sensor provided on the upper portion of the wafer detects a change in the surface temperature, whereby the output of the heater can be controlled so that the wafer reaches a predetermined temperature.

[0012]

The present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic view showing Embodiment 1 of the present invention.

In the figure, a wafer 1 is supported on a proximity pin 3 and placed on a hot plate 2. A sensor 5 that detects radiant heat from the wafer 1 is installed above the wafer 1, and the sensor 5 is connected to an arithmetic processing unit 6. The arithmetic processing unit 6 calculates the surface temperature of the wafer 1 based on the output signal of the sensor 5.

Further, the temperature control section 7 controls the output of the heater 4 incorporated in the hot plate 2 based on the temperature output signal of the arithmetic processing section 6 so that the surface temperature of the wafer becomes a set value.

As a result, the wafer 1 is baked at the surface temperature below the set value.

(Second Embodiment) FIG. 2 is a schematic view showing a second embodiment of the present invention.

In the proximity bake, the wafer is usually placed on the three pins, but the three pins (one pin in FIG. 2) is caused by the dust on the back surface of the wafer or the pin surface. Omit the proximity pin of
If only one of the two (only two of them are shown) has a different height than the other pins, the temperature of the wafer in this part will be higher than in other parts, Or it will be low.

In the second embodiment, three radiant heat detecting sensors 5 are arranged above the three proximity pins, and the arithmetic processing section 6, the temperature control section 7, and the heater 4 are also provided in three systems.

The three sets of heaters 4 incorporated in the hot plate 1 are installed so as to correspond to the arrangement of the radiant heat detection sensor 5, which causes a deviation in the height of the three proximity pins 3. Even if the proximity gap becomes non-uniform, there is an advantage that the temperature difference generated on the wafer surface can be reduced because the three heaters 4 independently control the temperature.

[0021]

As described above, according to the present invention, the temperature of the wafer surface is detected and the temperature is controlled, so that stable baking processing can always be performed without being affected by the change in the proximity gap. Have an effect.

[Brief description of drawings]

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

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

FIG. 3 is a schematic view showing a conventional baking processing apparatus.

FIG. 4 is a diagram showing a relationship between a proximity gap and a wafer surface temperature in a conventional baking processing apparatus.

[Explanation of symbols]

 1 Wafer 2 Hot Plate 3 Proximity Pin 4 Heater 5 Radiant Heat Detection Sensor 6 Arithmetic Processing Section 7 Temperature Control Section

Claims (1)

[Claims] 1. A radiant heat sensor, an arithmetic processing unit, and a temperature control unit, wherein a semiconductor substrate is placed on a hot plate heated by a heater via a proximity pin to perform a baking process on the substrate. In the baking processing device, the radiant heat sensor detects radiant heat from the semiconductor substrate heated by the hot plate, and the arithmetic processing unit calculates the surface temperature of the semiconductor substrate based on the output signal of the radiant heat sensor. The temperature control unit controls the output of the hot plate heating heater to an output value at which the substrate surface temperature reaches the set temperature based on the temperature output signal from the arithmetic processing unit. Bake processing equipment.