JP2964192B2 - Heating equipment for semiconductor device manufacturing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device for applying a predetermined heat treatment to a semiconductor wafer by applying heat through a hot plate .
The present invention relates to a heating device for manufacturing .

[0002]

2. Description of the Related Art For example, in a photolithography process for manufacturing a semiconductor device, an adhesion process for improving the adhesion between a photoresist and a semiconductor wafer is performed prior to the application of a photoresist. Then, a heat treatment (prebake) for removing the solvent in the resist, polymerizing the resist, and solidifying the photoresist film is performed.

As an example of a heating device used for such adhesion processing and pre-baking, a semiconductor wafer is mounted on a heating plate made of a metal plate having a built-in heating resistor, and heat generated by the heating resistor is generated. It is provided to the wafer via a hot plate. Then, in order to heat the wafer at a predetermined set temperature, the temperature controller controls the power supplied to the resistance heating element to perform temperature control such that the temperature of the hot plate is set to the predetermined set temperature.

[0004] This type of temperature controller includes, for example, PID
A controller is used. The temperature of the hot plate (measured temperature) detected by the temperature sensor is compared with the set temperature,
When the comparison error is given to the PID controller, PID
The controller calculates a control amount for matching the temperature of the hot plate to the set temperature by calculating a predetermined calculation formula combining the proportional operation (P), the integral operation (I), and the differential operation (D),
This control amount is given to the power supply unit as a control signal.

[0005]

As described above, the temperature controller of this type of heating device controls the temperature of the hot plate by a closed loop mechanism including a PID controller. It has a function to prevent the situation. However, this temperature control function may not work. For example, if the temperature sensor becomes abnormal,
Even if the actual temperature of the hot plate is high, the PID controller determines that the hot plate temperature is low and continues to output a positive control amount to the power supply unit to match the measured temperature to the set temperature. May be amplified. Also, even if the microcomputer constituting the PID controller runs away,
An improper control amount is given to the power supply unit from the PID controller, and the hot plate may overheat.

Therefore, as a safety measure, a thermostat is attached to the hot plate, and when the temperature of the hot plate is overheated to a predetermined temperature higher than the above set temperature, the thermostat is operated at that temperature to forcibly switch the power supply circuit ( (Hardware-like). In this case, when the power supply to the heating resistor is cut off and the hot plate cools down, the thermostat switches to the original state, the power supply circuit conducts, and the heating resistor again generates heat and heats the hot plate. Then, when the temperature of the hot plate exceeds the operating temperature of the thermostat again, the power supply circuit is shut off. But,
Since the thermostat is a switch mechanism that mechanically opens and closes, a failure may occur such that the switch remains closed and does not open even when the operating temperature is reached. As a result, there is no stopping the increase in the temperature of the hot plate, and as a result, the hot plate or the wafer may be burned, or may be ignited from the hot plate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a multi-stage safety protection mechanism prevents a loss of a hot plate or a fire accident as much as possible, and provides a highly accurate temperature control.
Semiconductor device that enables adjustment and protection operation and easy replacement and repair
An object of the present invention is to provide a heating device for manufacturing a chair .

[0008]

To achieve the above object, according to the Invention The semiconductor device manufacturing heating apparatus of the present invention, semiconductor
Semiconductor device that performs predetermined processing by heating the body wafer
The semiconductor wafer is placed on a heating device for manufacturing.
For the front side of the first plate and the back of this first plate
A second plate integrally joined from the side,
Discrete first, second and third notches in the second plate
A heat conductive heat plate arranged and provided in the
An electric power supply is provided between the first and second plates to convert electric power into heat.
Heat generating means for generating heat by replacement; and the second press of the hot plate.
Back of the first plate through a first notch of the plate
A temperature sensor detachably mounted in a state of contact with the heating plate, and supplying the temperature of the hot plate to the heat generating means in accordance with an output signal of the temperature sensor so as to match a temperature set for the heating process. A hot plate temperature controlling means for controlling electric power, and a second notch of the second plate of the hot plate.
Can be attached and detached in contact with the back of the first plate
And a switch circuit electrically connected in series to the heating means, wherein the switch circuit is provided when the first temperature sensor detects a first operating temperature higher than the set temperature. blocked, and the temperature switch means for holding the cut-off state irrespective of the temperature of the hot plate until predetermined reset operation is performed, first the second plate of the hot plate
3 contacts the back surface of the first plate through the notch
And a temperature fuse electrically connected in series to the heating means and melting at a second operating temperature higher than the first operating temperature.

[0009]

In normal operation, the temperature of the hot plate is returned to the set temperature by the adjusting function of the hot plate temperature control means even if the temperature of the hot plate is going to rise above the set temperature. When the hot plate temperature control unit fails and the temperature of the hot plate rises and reaches a first operating temperature higher than the set temperature, the temperature switch unit operates to cut off the power supply to the heat generating unit. Here, the temperature switch means does not return until the reset operation is performed irrespective of the temperature of the hot plate, that is, even if the temperature of the hot plate falls below the first operating temperature or the set temperature, Overheating and shutting off are not repeated many times. Also, the temperature switch means
In the event of a failure, the stage at which the temperature of the hot plate reaches the second operating temperature
On the floor, the thermal fuse melts and supplies power to the heating means.
Cut off, which prevents the hotplate temperature from getting higher
Is done. Temperature sensor and temperature switch of hot plate temperature control means
The temperature sensitive part of the means and the thermal fuse are located on the second side on the back side of the hot plate.
First, second and third discretely formed plates
3 is detachably buried and mounted in the notch of
A single deposition temperature (more precisely, the temperature of the first plate of the hot plate)
Temperature), high-precision temperature adjustment and protection
And repair can be easily performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a configuration of a heating device according to an embodiment of the present invention. This heating device may be used, for example, for a pre-baking process or a post-baking process in a resist coating process in semiconductor device manufacture.

In this heating device, the hot plate 10 is a disk made of a metal having high thermal conductivity, for example, aluminum.
On the upper surface 10a, a semiconductor wafer 12 is mounted as an object to be processed. Inside the heating plate 10, a heating resistor 14, a temperature sensor 16, a temperature sensing portion 18a of a thermostat 18, and a temperature fuse 20 are embedded and mounted.

Heating resistor 14 is connected to thermal fuse 20, SS
R (Solid State Relay) 24 and relay switch 26
Are electrically connected in series, and the power from the AC power supply 22 is S
The heating resistor 14 is supplied to the heating resistor 14 via the SR 24, the thermal fuse 20, and the relay
4 generates resistance heat, and the heat heats the hot plate 10, so that the wafer 12 is subjected to a heat treatment through the hot plate 10.

The switching of the SSR 24 is controlled by a pulse width control signal SM from the temperature control circuit 28, and the SSR 24 operates to supply AC power to the heating resistor 14 for a time corresponding to the pulse width of the control signal SM.

The temperature control circuit 28 compares the output signal (temperature detection signal) of the temperature sensor 16 with a set value to generate a comparison error, and a PID controller obtains a control amount corresponding to the comparison error. Generates a pulse width control signal SM corresponding to. Thus, the temperature control circuit 28
Performs a closed-loop temperature control so that the temperature of the hot plate 10 is adjusted to the set temperature.

The temperature control circuit 28 is connected to the main controller 30, and exchanges a hot plate temperature measurement value, a status signal, a control signal, and the like between the two. When the main controller 30 detects an abnormality or failure of the temperature control circuit 28 from the communication with the temperature control circuit 28, the main controller 30 supplies a control signal SX to a switch control circuit 32, which will be described later,
6 is cut off. The temperature sensor 16
For example, it comprises a platinum temperature sensor or a thermocouple. In this embodiment, the temperature sensor 16, the temperature control circuit 28 and the SSR 24 constitute a hot plate temperature control mechanism.

The thermostat 18 has a temperature sensing part 18a.
Is embedded in the hot plate 10. When the temperature of the hot plate 10 exceeds the first predetermined temperature, the thermostat 18 operates to output a predetermined output signal SR, and in response to the signal SR, the switch control circuit 32 shuts off the relay 26. It has become. The operating temperature of the thermostat 18 is set within a range where the hot plate 10 is not damaged by overheating.
Is selected to be higher than the set temperature range. For example,
When the set temperature range of the hot plate 10 is 180 ° C. or less, the operating temperature of the thermostat 18 is selected to be about 230 ° C. In this embodiment, the thermostat 18, the switch control circuit 32, and the relay 26 constitute a temperature switch mechanism.

The thermal fuse 20 makes thermal contact with the hot plate 10 and is electrically connected in series with the heating resistor 14. Therefore, when the heating plate 10 is overheated and exceeds a second predetermined temperature higher than the first predetermined temperature, the temperature fuse 20 is melted and power is not supplied to the heating resistor 14. The operating temperature of the thermal fuse 20 is selected to be higher than the operating temperature of the thermostat 18 and within a range that does not cause damage from the hot plate 10 due to ignition or the like, for example, about 300 ° C.

FIG. 2 shows a mounting structure of the temperature sensor 16, the thermostat temperature sensing portion 18a and the temperature fuse 20 to the hot plate 10 of the present heating apparatus. The hot plate 10 is a face plate 10 on the front side which has been subjected to a surface treatment such as a tuffram treatment.
A, and a heater plate 10B on the back side in which a coiled nichrome wire or the like is incorporated as the heating resistor 14. The face plate 10A is formed in a tray shape as shown in the figure when viewed from the back side, and has a circular convex surface portion 10b at the center thereof, and an annular concave portion between the peripheral edge portion 10c of the face plate 10A and the central convex surface portion 10b. Annular heater plate 10
By fitting B, both plates 10A and 10B are integrally joined.

Notch portions 10d, 10e and 10f are discretely formed in the heater plate 10B.
A temperature sensor 16 is fixed in d, a thermostat temperature sensing part 18a is in the notch 10e, and a temperature fuse 20 is fixed in the notch 10f by screws or the like in a state of contacting the back surface of the face plate 10A. Be attached. Both terminals 14a and 14b of the heating resistor 14 are connected to a fuse 20 and a relay switch 26 (not shown in FIG. 2) outside the heater plate 10B.

As described above, the temperature sensor 16, the thermostat temperature sensing portion 18a and the temperature fuse 20 are detachably embedded in the cutouts formed by the face plate 10A and the heater plate 10B. The same temperature of the hot plate can be sensed by the unit, and installation, replacement and repair are easy.

Next, an operation of preventing excessive heating in the present heating device will be described. In a normal state, that is, as long as the hot plate temperature control mechanism including the temperature sensor 16, the temperature control circuit 28, and the SSR 15 is operating normally, even if the temperature of the hot plate 10 exceeds the set temperature, the negative feedback control is performed. The temperature of the hot plate 10 is returned to the set temperature by reducing the power supply to the heating resistor 14 by working.

However, when an abnormality occurs in the hot plate temperature control mechanism and normal temperature control cannot be performed, an abnormal situation is transmitted to the main controller 30 through the temperature control circuit 28, and the main controller 30 switches to the switch control circuit 32. Control signal SX to turn off the relay switch 26. As a result, the power supply to the heating resistor 14 is stopped, and the excessive heating of the heating plate 10 is prevented.

However, if there is an abnormality in the PID controller or the communication control unit in the temperature control circuit 28, an abnormal situation of the hot plate temperature control mechanism may not be transmitted to the main controller 30. In this case, the hot plate 10 overheats,
When that temperature exceeds the operating temperature of the thermostat 18 (about 230 DEG C.), the thermostat 18 operates and generates an output signal SR. Then, in response to this signal SR, the switch control circuit 32 cuts off the relay switch 26 and cuts off the power supply to the heating resistor 14. Therefore, the overheating of the hot plate 10 is stopped before the tufram treated surface of the face plate 10A is burned. Further, the switch control circuit 32 has a state storage function, and until the reset operation is performed from the outside, the hot plate 10
Even if the temperature of the thermostat 18 becomes lower than the operating temperature of the thermostat 18, the power supply to the heating resistor 14 is not restored.

As described above, even if the hot plate 10 is overheated due to the failure of the hot plate temperature control mechanism, the thermostat 1 is normally used.
8. The temperature switch mechanism including the switch control mechanism 32 and the relay 26 operates to prevent the temperature of the hot plate 10 from rising excessively,
0 can be reused.

If the temperature switch mechanism breaks down and power continues to be supplied to the heating resistor 14, the hot plate 10 is overheated to such an extent that the treated surface of the face plate 10A is burned. When the temperature exceeds the operating point of the thermal fuse 20 (about 300 ° C.), the thermal fuse 20 melts, and at that time, the power supply to the heating resistor 14 is cut off. As a result, the hot plate 10 cannot be reused, but damage such as ignition is prevented beforehand, so that secondary disasters to nearby members, devices, and the like are avoided. Further, once the thermal fuse 20 is melted, power is not resupplied to the heating resistor 14 unless a new thermal fuse is attached, so that there is no reheating of the hot plate 10 and there is a possibility that the danger may recur. Absent.

As described above, in the heating apparatus of this embodiment, the hot plate temperature control mechanism (16, 28, 24)
And when the hot plate temperature control mechanism fails, the main controller 30 or the temperature switch mechanism (18,
32, 26) prevent overheating of the heating plate 10 and protect the heating plate 10, and when the temperature switch mechanism breaks down, the temperature fuse 20 blows itself to ensure overheating of the heating plate 10. The safety and reliability have been greatly improved because the fires were stopped and fires were prevented. Further, since the temperature sensor 16, the thermostat temperature sensing part 18a and the temperature fuse 20 are detachably embedded in the heating plate 10, respectively, the same heating plate temperature can be sensed by the temperature sensing parts of each part, so that high accuracy can be achieved. The temperature control and protection operation can be performed with ease, and replacement and repair can be easily performed.

The operating temperature of the thermal fuse 20 can be set to a temperature at which the hot plate 10 can be reused, for example, about 250 ° C. It is also possible to provide a plurality of thermostats 18 having different operating temperatures in parallel and to operate the temperature switch mechanism in multiple stages. The configuration and control method of the hot plate temperature adjusting mechanism may be other than the above-described embodiment. Further, a heating resistor 1 is used as a heating means.
Instead of 4, an infrared lamp, an induction heater, or the like can be used.

As described above, according to the heating device for manufacturing a semiconductor device of the present invention, a multi-stage safety protection mechanism is provided.
As much as possible to prevent burnout or fire accidents
・ Improvement of reliability and feeling of each part
The hot plate can be attached to and detached from the hot plate, and the same hot plate temperature is detected.
High-precision temperature adjustment and protection
Operation and easy replacement and repair.
it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a heating device according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a mounting structure of sensors on a hot plate according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Hot plate 12 Semiconductor wafer (processed object) 14 Heating resistor 16 Temperature sensor 18 Thermostat 20 Temperature fuse 22 AC power supply 24 SSR 26 Relay switch 28 Temperature control circuit 30 Main controller 32 Switch control circuit

Claims (1)

(57) [Claims] 1. A semiconductor wafer is heated to perform a predetermined process.
In a heating device for manufacturing a semiconductor device , a first plate on a front side for mounting the semiconductor wafer.
And the second plate integrally connected to the first plate from the back side.
And the second plate is provided with first and second plates.
And a heat transfer device having a third cutout portion provided discretely.
A conductive hot plate, and first and second plates of said hot plate.
A heating means provided between the heating plate and the heat generating means for converting electric power into heat and generating heat, and a first cutout of the second plate of the heating plate.
Detachable while in contact with the back surface of the first plate
A hot plate temperature control having an attached temperature sensor and controlling electric power supplied to the heat generating means so as to adjust the temperature of the hot plate to a set temperature for the heat treatment in accordance with an output signal of the temperature sensor; Means and via a second notch in said second plate of said hot plate
Detachable while in contact with the back surface of the first plate
Has an attachment has been temperature-sensing portion and said heating means to electrically switch circuits connected in series, interrupting the switch circuit a first operating temperature higher than the set temperature when the temperature sensing portion senses And a temperature switch means for maintaining the cutoff state irrespective of the temperature of the hot plate until a predetermined reset operation is performed, and a third cutout portion of the second plate of the hot plate.
Detachable while in contact with the back surface of the first plate
A heating device for manufacturing a semiconductor device, comprising: a temperature fuse mounted and electrically connected in series to the heating means, and melting at a second operating temperature higher than the first operating temperature.