JPH077758B2 - Pressure controller for sputtering equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pressure control device for a sputtering apparatus that supplies electric power to a semiconductor substrate or the like from a DC power source to perform sputtering processing on the substrate.

Conventionally, when a film is formed on a substrate in a sputtering apparatus of this type, an electrode and a substrate to be processed are provided in a vacuum processing chamber so as to face each other, and a constant flow rate of Ar gas is introduced into the chamber to form a vacuum pump. Then, it is general to supply electric power of a relatively small voltage from a DC power source to the electrodes and the substrate while performing vacuum evacuation so that the pressure in the chamber becomes constant. In this case, the substrate is replaced with a new one each time the sputtering process is completed, and the process is continued, but the sputtering current flowing through the electrode and the substrate is very small, for example, in the range of about 1 A or less due to changes in the state of the electrode, etc. The thin film formation rate of the substrate changes due to the change and a minute change of the current, which makes it difficult to form a thin film of uniform film quality on each substrate. Further, if the sputtering current changes during film formation on a certain substrate, the film quality will not be stable and a high-performance film cannot be formed.

An object of the present invention is to provide an apparatus capable of forming a film with good film quality by controlling the introduction of a processing gas into a vacuum processing chamber of a sputtering apparatus having a DC power source to prevent minute changes in the sputtering current. In the vacuum processing chamber provided with an exhaust pipe connected to a vacuum pump and an introduction pipe for introducing a processing gas such as Ar gas, an electrode and a substrate to be sputter-deposited are provided so as to face each other. In a sputtering apparatus of a type in which a DC power source is energized from a DC power source through a power supply circuit so as to generate a plasma discharge, a current measuring device for detecting a current flowing through the power supply circuit is provided and the introduction is performed. The pipe is provided with a flow control valve for adjusting the flow rate of the processing gas flowing through the pipe, and the flow control valve adjusts the flow rate of the processing gas when the detected current value of the current measuring device increases or decreases above a set current value. Characterized in that to connect the controller to control almost set current value current values.

An embodiment of the present invention will be described with reference to the drawings, with reference numeral (1)
Is a vacuum processing chamber, (2) is an exhaust pipe connected to the vacuum pump (4) from the processing chamber (1) through a valve (3),
(5) is an introduction pipe for introducing a processing gas such as Ar gas into the processing chamber (1) through a stop valve (6), and (7) is opposed to the substrate (8) in the processing chamber (1). The cathode electrode (7) and the substrate (8) are provided with a constant voltage power from a DC power supply (9) through a power supply circuit (10).

This structure is the same as the conventional one. In this structure, for example, when the cathode electrode (7) starts sputtering or when an abnormal discharge occurs, released gas is emitted and the pressure fluctuates, which increases the ionic current. It is not possible to prevent the processing speed of the substrate (8) from changing.

Therefore, in the present invention, the current measuring device (11) is provided in the power supply circuit (10).
And a flow control valve (12) for adjusting the flow rate of the processing gas in the introduction pipe (5), and the operation of the flow control valve (12) is controlled by the controller (13). When the detected current value of the current measuring device (11) increases or decreases with respect to the set current value, for example, the current value at which the board (8) can be subjected to a preferable discharge process, the controller (13) produces a difference value between the current values. The valve opening of the flow control valve (12) is changed according to the vacuum processing chamber (1)
Control to change the internal pressure. Specifically, when the difference value is positive, that is, when the detected current value exceeds the set current value, the controller (13) reduces the valve opening degree of the flow control valve (12) to the vacuum processing chamber (1). An instruction to reduce the flow rate of the inflowing processing gas is given to the valve (12), and when the difference value is negative, that is, when the detected current value is lower than the set current value, the controller (13) controls the flow control valve (12). If the instruction to increase the valve opening and increase the flow rate of the processing gas is given, and the detected current value matches the set current value, the controller (1
In 3), since the valve opening of the valve (12) is maintained in that state, no instruction is given to change the valve opening. The valve opening of the flow control valve (12) can be changed in a short time, and the amount of processing gas introduced into the vacuum processing chamber (1) can be slightly changed. It is possible to quickly and precisely control the flow rate of the processing gas in response to the above condition and restore the current value to the set value.

The reason why the current flowing through the electrode (7) and the substrate (8) decreases when the flow rate of the processing gas flowing into the vacuum processing chamber (1) is reduced when the current detected by the current measuring device (11) is large is Although it is not clear, it is presumed that the cause is that the partial pressure of the processing gas in the chamber (1) becomes small. Conversely, if the processing gas is increased when the detected current is small, the partial pressure of the processing gas becomes smaller. It is considered that the current flowing through the rising electrode (7) and the substrate (8) increases, and the processing speed of the substrate (8) can be controlled in proportion to the magnitude of the current.

The current measuring device (11) detects a current flowing through the power supply circuit (10) by converting it into a voltage, and the voltage signal is optically isolated to the indicating controller (14) so as to prevent noise from entering. Introduced via (15). In the indicating controller (14), the detected current value and the set current value represented by the voltage signal are calculated, and the difference value is the same as the amplifier (15) in the amplifier (16).
A voltage signal is input to the controller (13) via.
(17) is a manual / automatic changeover switch, (18) is a flow rate controller for manually operating the controller (13), (19) is a flow rate indicator, and (20) is an introduction pipe (5).
Is a flow rate sensor for detecting the flow rate of the processing gas.

The operation will be described. The inside of the vacuum processing chamber (1) is evacuated through the exhaust pipe (2) and a processing gas such as Ar gas is introduced through the introduction pipe (5), and then the electrode (7) and the substrate. (8)
Plasma discharge is generated in the gas between and to form a thin film of the substance of the electrode (7) on the surface of the substrate (8), for example.

When the film forming speed of the substrate (8) changes due to the consumption of the electrode (7) or the pressure change in the chamber (1) due to the change of the exhaust speed from the exhaust pipe (3), the power supply circuit (10) Is detected by the measuring instrument (11) as a minute change in the current value of. When the detected current value deviates to the plasma side from the preferable set current value, the controller (13) operates the flow rate control valve (12) to reduce the processing gas flow rate, and when deviated to the negative side, the processing gas flow rate increases. Since the valve (12) continues to operate until the detected current value and the set current value match or almost match, the processing speed of the substrate (8) is related to the change of the electrode (7), the pressure change of the chamber (1), etc. Can be maintained almost constant.

As described above, according to the present invention, the electrodes in the vacuum processing chamber of the sputtering apparatus, the current measuring device for detecting the current from the DC power source flowing to the substrate is provided, and the current value detected by this increases or decreases with respect to the set current value. Since the controller controls the flow control valve to control the flow rate of the processing gas flowing into the vacuum processing chamber, the flow rate of the processing gas can be changed minutely in response to minute changes in the current value. It is possible to restore the set current value to a desired value, and the substrate can be subjected to film formation processing with good film quality at a constant speed without being affected by changes in the electrode state and discharge state, and it is possible to process multiple substrates uniformly. Has the effect of.

[Brief description of drawings]

 The drawing is a diagram of an embodiment of the invention. (1) ... vacuum processing chamber, (2) ... exhaust pipe (5) ... introduction pipe, (7) ... electrode (8) ... substrate, (9) ... DC power supply (10) ... power supply circuit, (11) ... current Measuring instrument (12) ... Flow control valve, (13) ... Controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyo Miyagawa 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside the Totsuka Plant, Hitachi Ltd. (72) Inventor Satoru Hashimoto 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa (72) Inventor, Misao Kuroshita 49-11, Sasanodai, Asahi-ku, Yokohama-shi, Kanagawa (56) References JP-A-57-180131 (JP, A) JP-A-56-7432 (JP, A) JP-A-60-206028 (JP, A)

Claims (1)

[Claims] 1. A vacuum processing chamber provided with an exhaust pipe connected to a vacuum pump and an introduction pipe for introducing a processing gas such as Ar gas, the electrodes and the substrate to be sputter-deposited are provided facing each other.
In a sputtering device for energizing the electrode and the substrate from a DC power supply through a power supply circuit so as to generate plasma discharge in the processing gas, a current measuring device for detecting a current flowing through the power supply circuit is provided and A flow control valve for adjusting the flow rate of the processing gas flowing through the introduction pipe is provided, and the flow control valve adjusts the flow rate of the processing gas when the detected current value of the current measuring device increases or decreases more than the set current value. A pressure control device for a sputtering apparatus, which is connected to a controller for controlling a detected current value to a substantially set current value.