JPH05182916A - Method and apparatus for plasma-processing - Google Patents

Abstract

PURPOSE:To always plasma-process under suitable processing conditions by so controlling an object to be deeply controlled in relation to a monitored value that physically and chemically monitored values during plasma-processing become predetermined values. CONSTITUTION:A state of plasma-processing is monitored by detectors such as a self-bias detector 8, a spectral intensity detector 9, a plasma density detector 10, etc., and monitored results are input to a CPU 1. The CPU 1 selects, if the monitored results do not coincide with processing conditions to be a target, an object to be controlled in deepest relation with the discordant monitored value, calculates the degree of an increase or decrease in the object to be controlled, and controls the object to be controlled. For example, if the plasma density is not a predetermined value, applying power is selected and controlled. Thus, a plasma-process by a closed loop can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method and a plasma processing apparatus for manufacturing an integrated circuit or the like on a silicon wafer by depositing or etching a thin film on the surface of the silicon wafer.

[0002]

2. Description of the Related Art Plasma processing is to perform film formation (CVD) and etching on the surface of a wafer (substrate to be processed) by utilizing plasma obtained by exciting a reaction gas under reduced pressure.

In such a plasma processing step, applied power, operating pressure, gas species and its composition, exhaust capacity, bias voltage, frequency of applied power supply, processing time, etc. are used as processing conditions (hereinafter referred to as recipe). Set and process.

Conventionally, this recipe has been set in advance by obtaining various conditions empirically and / or theoretically depending on the processing purpose of the substrate to be processed, the object to be processed, the apparatus used, and the like.

[0005]

As described above, in the conventional plasma processing, the processing conditions are set in advance and the processing is performed under the fixed conditions. Therefore, if the processing conditions are not appropriate, or if the processing conditions become incorrect during the process, there is a problem that the scheduled plasma processing cannot be performed or the processing accuracy decreases and product quality is affected. It was

In view of the above situation, the present invention intends to carry out plasma processing while monitoring physical and chemical monitor values during processing and always maintaining appropriate processing conditions.

[0007]

The present invention monitors a physical or chemical monitor value during plasma processing and controls a control target deeply related to the monitor value so that the monitor value becomes a predetermined value. Plasma processing method and detector for monitoring physical and chemical monitor values during plasma processing such as plasma density, electron temperature, emission spectral intensity, and self-bias voltage, and control target such as applied power and operating pressure based on the detection result Of these, an arithmetic processing unit that selects a control target that is closely related and calculates the control amount,
The present invention relates to a plasma processing apparatus including a controller that controls the controlled object based on a signal from the arithmetic processing unit.

[0008]

The physical and chemical monitor values during processing required to achieve the required processing performance are monitored, and the monitor values to be changed are most relevant in order to maintain the monitor values at predetermined targets. Control deep control target.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Physical and chemical monitor values that affect plasma processing conditions include a self-bias voltage in a plasma generation state, plasma emission spectral intensity, plasma density, and electron temperature. These monitor values are related to the self-bias voltage. Is the voltage value in the circuit, and the emission spectral intensity of the plasma, plasma density, electron temperature, etc.
It can be detected by a plasma probe measurement or the like.

The factors to be controlled include applied voltage, operating pressure, applied power, etc. The self-bias voltage, the emission spectral intensity of plasma, the plasma density, the electron temperature, etc. are related to each other, If any one of the factors to be controlled fluctuates, a plurality of the monitor values will fluctuate.

However, the inventor of the present invention pays attention to the fact that there are the physical and chemical monitor values that are particularly closely related to each control target factor, and when a certain monitor value is managed at a predetermined value, the control target that is strongly related to each other. Controlling a factor, and when other monitor values fluctuate due to this control, it tries to control and converge the control target factor that is particularly closely related to the fluctuating monitor value to make it converge and control the processing condition to an appropriate one. Is.

Alternatively, when any one of the control target factors is changed, the influence coefficient between the affected monitor value and the control target factor is previously obtained by an experiment or the like, and a certain monitor value is set to a predetermined value. In the case of managing the above, it is intended to control a plurality of control target factors.

A description will be given below with reference to FIG.

In the figure, 1 is an arithmetic processing unit (CPU),
The CPU 1 has an input device 2 for inputting processing conditions, a storage device 3 for storing the set processing conditions, a display device 4 for displaying processing conditions, processing progress, processing results, etc., and applied power control for controlling the processing conditions. 5, the operating pressure controller 6, the applied power controller 7 ... Are connected, and the detection results from the self-bias detector 8, the emission spectral intensity detector 9, the plasma density detector 10, etc. are input to the CPU 1. It is supposed to be.

As described above, basic processing conditions are input from the input device 2, and the processing conditions are stored in the storage unit 3. Plasma processing is performed based on the input processing conditions, and the state of the plasma processing is monitored by detectors such as the self-bias detector 8, the emission spectral intensity detector 9, and the plasma density detector 10, and the monitoring result is as described above. It is input to the CPU 1.

When the monitoring result and the target processing condition do not match, the CPU 1 selects a control target that is most closely related to the monitor values that do not match, and further increases or decreases the control target. It is calculated whether or not the control target is controlled.

The control result is detected by the detector, it is judged whether or not the desired state is controlled, and if the desired state is not reached, the above-mentioned control is repeated.

For example, if the plasma density is not a predetermined value as a result of monitoring, the CPU 1 selects the applied power that is a control target closely related to the plasma density, and changes the applied power value to vary the applied power. The applied power controller 5 calculates and outputs a control signal to the applied power controller 5. The applied power controller 5 controls the applied power, which is one of the plasma generation conditions, by increasing or decreasing the applied voltage, the applied current, and the like. The state of plasma is detected by the plasma density detector 10, and the control result is fed back to the CPU 1.

As described above, the CPU 1 may select a plurality of control objects and simultaneously control a plurality of control objects.

[0021]

As described above, according to the present invention, the physical and chemical monitor values during processing, which are important for achieving the processing performance required in plasma processing, are monitored to optimize the plasma processing conditions. Since it is controlled as described above, plasma processing by a closed loop becomes possible, and excellent effects such as improvement of processing reliability and easy analysis of the cause of a processing failure when a processing failure occurs are exhibited.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 CPU 2 Input device 3 Storage device 4 Display device 5 Applied power controller 6 Operating pressure controller 7 Applied power controller 8 Self bias detector 9 Emission spectral intensity detector 10 Plasma density detector

Claims (2)

[Claims] 1. A plasma processing method comprising monitoring a physical or chemical monitor value during plasma processing, and controlling a control target deeply related to the monitor value so that the monitor value becomes a predetermined value. .. 2. A detector for monitoring physical and chemical monitor values during plasma processing such as plasma density, electron temperature, emission spectral intensity, and self-bias voltage, and control of applied power, operating pressure, etc. based on the detection result. A plasma processing apparatus comprising: an arithmetic processing unit that selects a control target that is closely related to one of the targets and calculates a control amount; and a controller that controls the control target based on a signal from the arithmetic processing unit. ..