JPH09134886A - Ramping temperature control method for semiconductor manufacturing equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To eliminate the time delay in ramping temperature control and achieve the target temperature quickly and accurately. 1. A ramping temperature control method for controlling a temperature of a semiconductor manufacturing apparatus according to a set value SV of a temperature change, a deviation value α between a set value SV and an actual temperature of the semiconductor manufacturing apparatus is obtained in advance, and temperature control is performed. Within the range (time t1 ') that does not exceed the target value, the temperature control is performed according to the set value SV' corrected by adding the deviation value α, and the target value is theoretically achieved by the set value SV. The interval from the time t2 when the temperature reaches the target value is made as short as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control method for a semiconductor manufacturing apparatus such as a vertical diffusion / CVD apparatus, and more particularly to a ramping temperature control method for achieving a target temperature by a lamp input.

[0002]

2. Description of the Related Art In order to perform a predetermined process on a substrate such as a semiconductor wafer or a glass substrate, for example, in an electric furnace of a semiconductor manufacturing apparatus, it is required to achieve a target temperature quickly and accurately. Such temperature control is performed by controlling the operation amount input to the heater control unit that controls the heating heater, and controlling the control amount output from the heater control unit to the heating heater. That is, the control amount is changed to a desired target value by changing the operation amount, and thereby the furnace temperature of the electric furnace by the heater is changed to a target value.

There are various methods for controlling the temperature of the semiconductor manufacturing apparatus, and one of them is the ramping control method. In this ramping control method, the target temperature (target value) for the control amount of the heater control means
When giving, the control amount is not immediately controlled toward the target value, but the rate of temperature change per unit time is given as a ramp input and gradually controlled toward the target value over time. For example, the control amount in the temperature stable state is 800
When the target temperature is 850 ° C. and the target value is 850 ° C., the ramp input is given at a rate of increase of 5 ° C./min to gradually change the temperature inside the electric furnace.

[0004]

Here, in the ramping temperature control method as described above, since the additional value control is performed, there is a difference between the set value (SV) due to the lamp input and the actual temperature change in the furnace. However, there is a problem that it takes a long time for the temperature inside the furnace to stabilize at the target temperature (target value). That is, as shown in FIG. 1, when the set value (SV) is used as a ramp input to raise the furnace temperature to the target value from time t0 to time t1, the actual change in furnace temperature is Deviations occur later than the set value and the temperature in the furnace stabilizes at the target value at time t2, which is later than time t1.

Such a delay in temperature control may not only delay the manufacturing process in the semiconductor manufacturing apparatus but may also deteriorate the quality of the product, and improvement thereof has been strongly desired. The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to eliminate a time delay in ramping temperature control and achieve a target value quickly and accurately.

[0006]

In order to achieve the above object, a ramping temperature control method for a semiconductor manufacturing apparatus according to the present invention is a ramping temperature control method for controlling a temperature of a semiconductor manufacturing apparatus according to a set value of a temperature change. A deviation value between the set value and the actual temperature of the semiconductor manufacturing apparatus is obtained in advance, and temperature control is performed according to a set value corrected by adding the deviation value within a range not exceeding a target value for temperature control. And

[0007]

In the temperature control in the semiconductor manufacturing equipment, the process value is repeatedly set under the same process condition (temperature condition, lamp input value, control parameter, etc.). The deviation value from the in-furnace temperature can be accurately obtained in advance by several trials. In the present invention, such a deviation value is obtained in advance, the set value of the lamp input used in the actual process processing is corrected by adding this deviation, and this correction is performed within the range not exceeding the target value of the temperature control. The ramping temperature control is performed using the set value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A ramping temperature control method for a semiconductor manufacturing apparatus according to an embodiment of the present invention will be described with reference to the drawings. First, before starting the ramping temperature control in the actual process treatment, the furnace temperature control by the lamp input is tried several times, and the deviation value between the set value by the lamp input and the actual furnace temperature of the semiconductor manufacturing equipment is calculated. Get in advance. That is, as shown in FIG. 1, the set value (SV) of the lamp input
The deviation value of the in-furnace temperature change with respect to is previously obtained, and this deviation value is stored in the table as a correction value α in association with the lamp input value and other process conditions.

Thereafter, the actual process processing is started, and the lamp input is corrected using the correction value α stored in the table when controlling the ramping temperature. That is, as shown in FIG. 2, when it is attempted to raise the furnace temperature to the target value from time t0 to time t1, the lamp input is changed to the set value (SV) used in the related art and the correction is performed. Temperature control is performed as a set value (SV ′) to which the value α is added. In this case, the corrected set value (SV ′) is used only until the time t1 ′ at which the target value is achieved by the set value (SV ′), and thus the temperature in the furnace is set to the target value. It prevents the situation that it greatly exceeds.

Here, in this embodiment, the operation amount input to the heater control means as a control target is PID (proportional / integral / derivative) controlled, and the set value given to this PID control is immediately set as the target value. The control and the ramping control in which the set value given to the PID control is the temperature change rate per unit time can be selected. In PID control,
As shown in FIG. 5, the operation amount input to the controlled object 2 is finely controlled by feedback processing by PID calculation based on the set value (SV ′) and the controlled variable (PV) of the controlled object 2, and is set as a target from the controlled object. The controlled variable is output.
That is, the target set value (S
V ') is input, and the operation amount (Y) for achieving the target value is input from the PID calculation means 1 to the control target (heater control means) 2. Then, the control amount (PV) output from the controlled object 2 is fed back to the PID calculation means 1 so that the control amount (PV) becomes a target value.

Next, the ramping temperature control method of this embodiment, which is carried out by the controller attached to the semiconductor manufacturing apparatus, will be described with reference to the processing procedure shown in FIG. First, it is determined whether the temperature is controlled by the lamp input (step S
1) In the case of control in which the set value is immediately set as the target value, the target value for temperature control is set as the set value (SV ') for PID control.
(Step S2), and temperature control by PID control is executed (step S3).

On the other hand, in the case of temperature control by lamp input, the correction value α stored in the table in advance is read (step S5), and this correction value α is set to the set value (SV) to be used for control. In addition, it is determined whether this value (SV + α) is equal to or greater than the target value (step S6). As a result, if it is equal to or more than the target value, the control in which the correction value α is added is stopped, and the target value for temperature control is set to the set value (SV ′) for PID control (step S2). PID control (step S3) is executed. On the other hand, the value (S
If V + α) is less than the target value, the corrected set value is used as the set value (SV ′) used for PID control (step S7), and PID control (step S3) is executed.

The above temperature control process is repeatedly performed periodically, and the target value can be achieved quickly and accurately even in the ramping control. That is, as shown in FIG. 2, when the temperature is controlled using the correction set value (SV ′) obtained by adding the correction value α to the set value (SV) by the lamp input, the time when the target value is achieved by the set value The time interval between t1 and the time t2 when the temperature inside the furnace actually stabilizes at the target value can be greatly shortened compared to the conventional case. In this case, the correction set value (SV ′) to which the correction value α is added theoretically reaches the target value at the time t1 ′ earlier than the time t1, so the correction by the correction value α is performed until the time t1 ′. It is avoided that the temperature in the furnace is overshot and overshoots the target value.

In the above embodiment, the embodiment based on the PID control is shown. However, the present invention can be applied to other control systems as well. The deviation may be corrected so as to minimize the influence of the tracking delay.

[0015]

As described above, according to the ramping temperature control method for a semiconductor manufacturing apparatus according to the present invention, the set value is corrected by using the deviation value due to the tracking delay. The target value can be changed quickly and accurately. Therefore, the electric furnace or the like of the semiconductor manufacturing apparatus can be quickly and accurately controlled to a predetermined temperature, the delay of the manufacturing process by the semiconductor manufacturing apparatus is prevented, and the accuracy of the process treatment is improved to achieve high quality. The product can be manufactured stably.

[Brief description of the drawings]

FIG. 1 is a graph illustrating an operation of a conventional ramping temperature control.

FIG. 2 is a graph illustrating an operation of ramping temperature control according to an exemplary embodiment of the present invention.

FIG. 3 is a flowchart showing a processing procedure of ramping temperature control according to an embodiment of the present invention.

FIG. 4 is a block diagram illustrating PID control.

[Explanation of symbols]

 2 controlled object, PV controlled variable, SV, SV 'set value, α deviation value,

Claims (1)

[Claims] 1. A ramping temperature control method for controlling a temperature of a semiconductor manufacturing apparatus according to a set value of a temperature change, wherein a deviation value between the set value and an actual temperature of the semiconductor manufacturing apparatus is obtained in advance, and a temperature control target is obtained. A ramping temperature control method for a semiconductor manufacturing apparatus, wherein temperature control is performed according to a set value corrected by adding a deviation value within a range not exceeding the value.