JPH01287264A - Production of transparent conductive film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to I/O devices used in recent video equipment, OA equipment, etc.
The present invention relates to a method for manufacturing a transparent conductive film of TO (Indium Tin Oxide).

BACKGROUND OF THE INVENTION Although there are various methods for producing a transparent conductive film of ITO, the recent mainstream method is sputtering, which has a high film forming speed. A conventional method for manufacturing a transparent conductive film using a sputtering method will be briefly described below. In the schematic diagram of the sputtering apparatus shown in FIG. 3, a cathode 3 to which a sputtering target 2 is attached is installed in a vacuum chamber 1 with an electrical insulator 4 in between. Board 5
is placed on the substrate holder 6 facing the sputtering target 2 . Electric power from a sputtering power supply 11 is supplied between the cathode 3 and the vacuum chamber 1, and plasma is generated between the sputtering target 2 and the substrate 5. The vacuum chamber 1 also includes a vacuum exhaust system 7 and a vacuum gauge 1.
2. A gas introduction system is installed. The gas introduction system consists of an argon gas introduction system 8 and an oxygen gas introduction system 9, each of which is equipped with a gas flow rate regulator 10, 10'.

The inside of the vacuum chamber is adjusted to a predetermined degree of vacuum by an evacuation system 7, and the degree of vacuum at that time is measured by a vacuum gauge 12. Here, the sputtering target 2 used when producing the ITO transparent conductive film is a sintered ITO target or an indium and tin alloy target. When using a sintered target, the film quality is best when a small amount of oxygen gas (10% or less) is mixed with argon gas, and when an alloy target is used, a few tens of percent of oxygen gas is mixed to form the film. Met.

Problems to be Solved by the Invention ITO has conductivity because tin acts as a donor and because oxygen vacancies exist in indium oxide. To generate oxygen vacancies, IT
There are cases where the oxygen content in the O thin film is somewhat less than the stoichiometric oxygen content of indium oxide (11203), so controlling the oxygen content during film formation is very important. However, even if the amount of oxygen is precisely controlled (especially when using a sintered ITO target, the filling rate of the target is only about 95% at most, and the remaining 5% is contained in the target voids). IT film formed by impure gas mainly composed of nitrogen scum
It was taken into the O film and deteriorated the quality of the ITO film.

In addition, nitrogen is often the main component of the scum released from the vacuum chamber and minute leak gases, and these gases are also used in IT.
The quality of the O film was getting worse. Therefore, it was not possible to achieve the desired yield of the ITO film produced.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a method for manufacturing an ITO transparent conductive film at a high yield.

Means for Solving the Problems The transparent conductive film manufacturing method of the present invention is based on the ratio In/lo of the oxygen gas intensity Io and nitrogen gas intensity In in the vacuum chamber, which is measured with a quadruple barrel mass spectrometer attached to the vacuum chamber. A transparent conductive film is created when the value of , which performs film formation.

Effect According to the above structure, when producing a transparent conductive film of ITO, the film is formed only when nitrogen gas, which has an adverse effect on film quality, is below a predetermined value, so that a transparent conductive film with good film quality is always stable. A film is formed.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a configuration diagram of a sputtering apparatus used in the transparent conductive film manufacturing method of the present invention. Note that parts common to the conventional example are given the same numbers.

A cathode 3 to which a sputtering target 2 is attached is installed in a vacuum chamber 1 with an electrical insulator 4 interposed therebetween. The substrate 5 is placed on a substrate holder 6 facing the sputtering target 2. Sputtering power supply 1
1 is supplied between the cathode 3 and the vacuum chamber 1, and a plasma is generated between the sputtering target 2 and the substrate 5. In addition, the vacuum chamber 1 includes a vacuum exhaust system 7.
, a vacuum gauge 12, a quadruple barrel mass spectrometer 13, and a gas introduction system are installed. The gas introduction system consists of an argon gas introduction system 8 and an oxygen gas introduction system 9, each of which has a waste flow rate regulator 1.
0.10' is attached, and a minute flow rate regulator 15 is further added to the oxygen gas introduction system. vacuum chamber 1
The inside of the chamber is adjusted to a predetermined degree of vacuum by an evacuation system 7, and the degree of vacuum at that time is measured by a vacuum gauge 12, and the gas composition is measured by a quadruple barrel mass spectrometry system 13. Here, the vacuum gauge 12,
The output signal from the calculation unit 14 of the quadruple bucket mass spectrometry system 13 is input to the film forming controller 16, and the film forming control signal is sent to the power source 11,
It is designed to be sent to a minute flow rate regulator 15.

FIG. 2 is a diagram showing an example of control conditions in the film forming controller 16 in the transparent conductive film manufacturing method of the present invention, and shows the ratio In/lo of the nitrogen gas intensity In and the oxygen gas intensity Io, and The relationship between the concentration of oxygen gas introduced in

The effects of this embodiment will be described below.

The interior of the vacuum chamber 1 is evacuated to a high vacuum before gas is introduced, and the degree of vacuum at that time is monitored by a vacuum gauge 12.

When a predetermined degree of vacuum is reached, sputtering gases of argon gas and oxygen gas are introduced, power necessary for sputtering is supplied from power source 11, and plasma is generated between cathode 2 and substrate 5.

In this example, a sputtering target 2 which is a sintered ITO target is used, and when the sputtering target 2 is sputtered by plasma, indium, tin, oxygen and nitrogen contained in the voids in the sputtering target 2 are removed from the target surface. Impure gases whose main components are mainly in the atomic state come out.

Here, when the nitrogen gas concentration in the gas present in the vacuum chamber 1 exceeded a certain value, the quality of the ITO film deteriorated. It was found that it is impossible to completely eliminate nitrogen gas, and that it has little effect on ITO film quality below a certain concentration. The amount of gas introduced and the power supplied are adjusted using the film forming controller 16 so that the ratio of nitrogen gas intensity to oxygen gas intensity is less than the value shown in FIG. conduct. This adjustment method will be briefly described below. Regarding the supplied power, if the power is small, a relatively large amount of nitrogen gas with low excitation energy will be emitted, so nitrogen gas is emitted from the sputtering target 2 with a small power for a certain period of time after the start of discharge. Note that film formation is not performed within this time.

Next, the electric power is gradually increased, and film formation is performed when the ratio of nitrogen gas intensity to oxygen gas intensity becomes less than a predetermined value (the value shown in FIG. 2). Here, in addition to the power supply adjustment described above, the amount of oxygen gas introduced into the vacuum chamber 1 is also finely adjusted so that the nitrogen gas concentration does not exceed a predetermined value.

Further, when the oxygen gas concentration in the argon gas increases, the film forming rate decreases, so in that case, the supplied power is increased to prevent the film forming rate from decreasing. Such adjustment of the gas flow rate and power supply is handled by a feedback mechanism within the film forming control machine, so that stable film forming is always performed.

Next, when an alloy target of indium and tin is used, it is basically the same as when using the above-mentioned sintered target, except that the amount of oxygen gas introduced into the vacuum chamber is larger, and it can be controlled in the same way. Stable film formation is possible.

Effects of the Invention The transparent conductive film manufacturing method of the present invention can always stably form an ITO transparent conductive film without being affected by nitrogen gas, which is an impurity gas during film formation, so that the product yield can be improved. improves. In addition, since the film forming conditions are automatically controlled, it can be expected to have a significant effect on maintenance-free film forming and labor savings.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a film forming apparatus used in a transparent conductive film manufacturing method according to an embodiment of the present invention, Fig. 2 is a diagram showing control conditions of gas composition in the same manufacturing method, and Fig. 3 is a diagram showing a conventional transparent conductive film manufacturing method. FIG. 2 is a configuration diagram of a film forming apparatus in a film manufacturing method. 13... Quadruple seed mass spectrometer, 14... Arithmetic unit, 15... Minute flow rate regulator, 16... Film forming controller. Agent's name: Patent attorney Toshio Nakao, 1 fool

Claims (3)

[Claims] (1) Oxygen gas intensity Io in the vacuum chamber is measured using a quadrupole mass spectrometer attached to the vacuum chamber using a thin film manufacturing apparatus equipped with a vacuum chamber, a vacuum evacuation system, a gas introduction system, a power supply, etc. and the ratio I of nitrogen gas intensity In
A transparent conductive film manufacturing method for manufacturing a transparent conductive film when n/Io is less than or equal to a predetermined value. (2) Oxygen gas intensity Io measured with a quadrupole mass spectrometer
2. The method for producing a transparent conductive film according to claim 1, wherein the power supplied from the power supply is adjusted so that the ratio In/Io of the nitrogen gas intensity In and the nitrogen gas intensity In is equal to or less than a predetermined value. (3) Oxygen gas intensity Io measured with a quadrupole mass spectrometer
2. The method of manufacturing a transparent conductive film according to claim 1, wherein the gas composition introduced into the vacuum chamber is changed so that the ratio In/Io of the nitrogen gas intensity In and the nitrogen gas intensity In becomes equal to or less than a predetermined value.