JP2807844B2 - Substrate heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a substrate heating apparatus.

(Prior Art) Generally, in a process of manufacturing a semiconductor device, a process of heating a substrate such as a semiconductor wafer to a predetermined temperature may be required, and a substrate heating apparatus is used in such a heat treatment process. Have been.

For example, in a step of transferring a circuit pattern using a precise photo transfer technique, a heating process called baking is performed, for example, after a photoresist liquid is applied to a semiconductor wafer.

A substrate heating apparatus that performs such a heating process includes, for example, a heating plate provided with heating means such as a resistance heating heater, a temperature sensor for detecting the temperature of the heating plate, and a resistance heating using a signal from the temperature sensor as a reference signal. It is composed of a temperature controller for adjusting the power supplied to the heater and controlling the temperature.

Then, the semiconductor wafer is placed on a hot plate controlled to a predetermined temperature by the temperature control device, and a heating process is performed. In addition, by placing the semiconductor wafer on the minute pins provided on the hot plate, a minute gap is provided between the hot plate and the semiconductor wafer, and the hot plate and the semiconductor wafer are brought into close contact with each other without contact. There is also a substrate heating device for heating in a state where the substrate is heated.

(Problems to be Solved by the Invention) However, in recent years, semiconductor devices tend to be highly integrated, and circuit patterns thereof have been increasingly miniaturized. For this reason, it has been desired that even the above-described conventional substrate heating apparatus can carry out processing with higher accuracy.

The present invention has been made in view of such a conventional situation, and has as its object to provide a substrate heating apparatus capable of performing a heat treatment more accurately than in the past.

[Means for Solving the Problems] That is, according to the present invention, in a substrate heating apparatus for heating a substrate by bringing the heating means into contact with or close to the substrate, a temperature detecting means for detecting a temperature of the heating means And control means for calculating an integrated value of the temperature detected by the temperature detecting means and the heating time of the substrate, and controlling the heating time so that the integrated value becomes a predetermined value. And

(Operation) The present inventors have conducted a detailed investigation and found that in the substrate heating apparatus, the temperature of the heating means (for example, a heating plate) is controlled to a predetermined temperature, but the temperature is not controlled when the heating process starts and ends. Loading a substrate (eg, a semiconductor wafer) on a hot plate
Upon unloading, the temperature of the hot plate fluctuates to some extent, and it takes a certain amount of time for this variation to subside. For this reason, even if the heat treatment is performed for a predetermined time, the temperature of the hot plate fluctuates during this time, so that the processing state changes due to the temperature fluctuation. Also, such temperature fluctuations
Since it varies depending on various conditions, for example, the temperature of the semiconductor wafer to be loaded, the processing interval, the processing time, and the like, it is difficult to suppress it.

Therefore, in the substrate heating device of the present invention, the control unit calculates an integrated value of the temperature detected by the temperature detecting unit and the substrate heating time, and sets the substrate heating time so that the integrated value becomes a predetermined value. Control.

The thermal energy for the substrate is determined by the integrated amount of temperature and time. Therefore, the amount of energy applied to the substrate can be made constant by correcting the energy fluctuation caused by the temperature fluctuation with time.

Thus, even if the processing temperature fluctuates, the total amount of heat supplied to the substrate becomes constant, and the processing can be performed more accurately than in the past.

(Example) Hereinafter, an example in which the present invention is applied to a substrate heating apparatus that performs a heating process on a semiconductor wafer or the like coated with a photoresist will be described with reference to the drawings.

As shown in FIG. 1, the substrate heating apparatus 1 is provided with a disk-shaped heating plate 3 on the upper surface of which a semiconductor wafer 2 can be placed. A heating element, for example, a resistance heater (not shown) is provided in the heating plate 3, and a power supply device 4 for supplying electric power is connected to the resistance heater. Further, a temperature sensor 5 for detecting the temperature of the hot plate 3 (the temperature near the mounting surface of the semiconductor wafer 2) is provided in the hot plate 3.

Further, a plurality of, for example, three through holes 6 are provided in the hot plate 3 so as to penetrate in the vertical direction.
Are provided with pins 7 respectively. In addition, hot plate 3
Is connected to a drive mechanism 8 and is configured to be able to move up and down with respect to the pin 7 as indicated by an arrow in the figure. When the semiconductor wafer 2 is loaded and unloaded on the hot plate 3, the hot plate 3 is lowered to protrude the pins 7 onto the hot plate 3, and the semiconductor wafer 2 is supported on the pins 7, A space is provided between the wafer 2 and the hot plate 3 for inserting a wafer support mechanism (not shown) of the transfer device. The drive mechanism 8 is controlled by a drive control unit 9.

Further, similarly to the conventional substrate heating device, the power supply device 4 described above adjusts the power supplied from the power supply device 4 to the resistance heater using the signal from the temperature sensor 5 as a reference signal. There is provided a temperature control device 10 for controlling the temperature at a predetermined temperature set in advance.

Further, in this embodiment, an integrated calorific value control device 11 is provided. The integrated calorific value control device 11 includes an integrated calorific value calculating unit 11a, an integrated calorific value setting unit 11b, and a comparing unit 11c.

The integrated calorie calculating unit 11a receives the wafer load signal (indicating that the semiconductor wafer 2 has been placed on the hot plate 3) from the drive control unit 9 that controls the drive mechanism 8, and the semiconductor wafer 2 The time (processing time) after being placed on the top is measured. Then, an integrated value of the processing time and the temperature detection signal of the temperature sensor 5 is calculated.

The integrated heat quantity setting unit 11b includes a storage unit such as a RAM, for example, and a desired integrated heat quantity set value is set and stored in advance in this storage unit.

The comparison unit 11c compares the integrated heat amount set value set in the integrated heat amount setting unit 11b with the integrated value calculated by the integrated heat amount calculation unit 11a. When the integrated value calculated by the integrated heat amount calculating unit 11a becomes equal to the integrated heat amount set value set in the integrated heat amount setting unit 11b, a process end signal is sent to the drive control unit 9. When a processing end signal is input from the comparison unit 11c, the drive control unit 9 lowers the hot plate 3 by the drive mechanism 8, moves the semiconductor wafer 2 from the hot plate 3 onto the pins 7, and ends the heating process. It is configured.

In the substrate heating apparatus 1 of this embodiment having the above-described configuration, the temperature control device uses the temperature detection signal of the temperature sensor 5 as a reference signal.
10 adjusts the electric power supplied from the electric power supply device 4 to the resistance heater to control the temperature of the hot plate 3 to a predetermined temperature.

Then, the hot plate 3 is lowered by the driving mechanism 8 so that the pins 7 are set to protrude above the hot plate 3, and in this state,
The semiconductor wafer 2 is placed on the pins 7 by, for example, an automatic transfer mechanism.

Thereafter, the hot plate 3 is raised, and the semiconductor wafer 2 is
It is moved onto the hot plate 3 from above, and the heat treatment is started.

At this time, the integrated wafer calorimeter 11a of the integrated calorimeter 11 puts the semiconductor wafer 2 on the hot plate 3 according to the wafer load signal from the drive controller 9 and the temperature detection signal from the temperature sensor 5. The integrated value of the accumulated time (processing time) and the processing temperature is calculated, and in the comparing unit 11c, the integrated heat amount set value set in the integrated heat amount setting unit 11b and the integrated value calculated in the integrated heat amount calculating unit 11a Compare with When the integrated value calculated by the integrated heat amount calculating unit 11a becomes equal to the integrated heat amount set value set in the integrated heat amount setting unit 11b, the comparing unit 11c sends a processing end signal to the drive control unit 9, and the drive control unit 9 drives the drive mechanism 8 to lower the hot plate 3 in response to the process end signal, moves the semiconductor wafer 2 from the hot plate 3 onto the pins 7, and ends the heating process.

Therefore, for example, when the semiconductor wafer 2 is loaded and unloaded on the hot plate 3, even if the temperature of the hot plate 3 fluctuates,
The total amount of heat supplied to the semiconductor wafer 2 becomes constant, so that more accurate processing can be performed as compared with the related art.

In the above embodiment, the substrate heating apparatus 1 in which the semiconductor wafer 2 is directly mounted on the heating plate 3 and heated is described. Is mounted, a minute gap is provided between the heating plate 3 and the semiconductor wafer, and the heating plate 3 and the semiconductor wafer 2 are not brought into contact with each other, and are heated in a state where they are brought close to each other. be able to.

[Effects of the Invention] As described above, according to the substrate heating apparatus of the present invention, even if the processing temperature fluctuates, the total amount of heat supplied to the substrate on which the processing is performed is constant, and the substrate is more accurate than the conventional one. Processing can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a substrate heating apparatus according to one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Substrate heating device, 2 ... Semiconductor wafer, 3 ... Hot plate, 4 ... Power supply device, 5 ... Temperature sensor, 6 ... Through hole, 7 ... Pin, 8 ... Driving mechanism, 9 ...... Drive control unit,
10 …… Temperature control device, 11 …… Integrated calorie control device, 11a…
... Integrated heat amount calculation unit, 11b... Integrated heat amount setting unit, 11c.

Claims (1)

(57) [Claims] 1. A substrate heating apparatus for heating a substrate by bringing a heating means into contact with or close to the substrate, a temperature detecting means for detecting a temperature of the heating means, a temperature detected by the temperature detecting means and the substrate A heating means for calculating an integrated value with the heating time, and controlling means for controlling the heating time so that the integrated value becomes a predetermined value.