JPS63250459A - Production of transparent conductive film - Google Patents

Abstract

PURPOSE:To form a transparent conductive film having uniform film quality at a high speed on a substrate with an in-line type sputtering device which forms the film on the substrate while moving the substrate by controlling a variable parameter by the emission intensity of the plasma generated between a conductive jig and metal target. CONSTITUTION:DC magnetron sputtering is executed by using the target 1 consisting of an In-Sn alloy to form a transparent ITO film consisting of In2O3 and SnO on the glass substrate 3 while a conductive substrate holder 4 mounted with the glass substrate 3 is moved successively in an arrow direction in a vacuum vessel and gaseous Ar and gaseous O2 are introduced into the vacuum chamber. The discharge plasma in a discharge space 5 is measured by an optical head 2 in this case and the flow rate of the gaseous O2 is so controlled that the specified emission intensity of the In atoms in the plasma is maintained. The transparent conductive film having a small specific resistance value is formed at a high speed on the glass substrate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method of manufacturing a transparent conductive film used in electronic devices and the like.

BACKGROUND OF THE INVENTION One method for forming a transparent conductive film of metal oxide is to perform sputtering using a metal as a target while introducing oxygen gas into a vacuum container. In particular, a high film formation rate can be obtained by measuring the generated plasma light and controlling variable parameters such as oxygen gas flow rate and discharge current so that the plasma intensity remains constant (Japanese Patent Laid-Open No. 59-63
Publication No. 76). When forming a so-called ITO film containing indium oxide and tin oxide, it is necessary to use a DC magnetron sputtering method using an alloy of In and Sn as a target.
It can be formed at a high deposition rate of n+in.

Problems to be Solved by the Invention With in-line sputtering equipment that deposits films while moving the substrate, it is difficult to deposit a transparent conductive film with uniform quality over the entire surface of the glass substrate using the above plasma light monitoring method. I could not do it. Since the discharge impedance is different between when there is a conductive substrate hole made of stainless steel or the like above the target and when there is an insulating substrate such as glass, there appears to be a difference in the upper discharge state. If the variable parameters are controlled so that the plasma intensity is the same, a reduced film is actually formed on the substrate holder. Under the influence of this, there was a problem in that a reducing film was also formed on the insulating substrate near the substrate holes. An object of the present invention is to solve the above-mentioned problems and provide a manufacturing method for forming a transparent conductive film of uniform quality on a glass substrate using this method even with an in-line sputtering apparatus.

Means for Solving the Problems In the present invention, variable parameters are controlled by the emission intensity of plasma generated between a conductive jig and a metal target.

Regardless of whether or not there is an insulating substrate above the working target, the impedance of the discharge monitors the plasma at a constant location, so a transparent conductive film of constant quality can always be formed.

EXAMPLE A method for manufacturing a transparent conductive film of the present invention will be explained with reference to FIG. Figure 1a is a plan view, and the cross-sectional view along A-8 is shown in Figure 1.
It is shown in the figure. In the figure, 1 is an alloy target of In and Sn and has a size of 127 mm x 381 mm. Introducing Ar gas and 02 gas into the sputtering chamber,
DC magnetron sputtering is performed by applying a DC voltage and discharging at a constant current of 2A. Reference numeral 2 denotes an optical head for measuring plasma, and the flow rate of 02 was controlled so that the light emission intensity of In atoms in the plasma measured by this head became constant. 2501I11 x 360ml11 glass substrate 3
The ITO film was formed while moving the stainless steel substrate holder 4 of 450 m1 x 450 mm in the direction of the arrow at a speed of 150 mm/min one after another in the direction of the arrow. The obtained ITO film was almost transparent anywhere on the substrate, and the resistivity distribution was 6 to 7×1o→Ω·CIW. When this film was annealed in vacuum, it was completely transparent and had a specific resistance of about 2.5xl.
It became O-4Ω·cm.

FIG. 2 shows changes in the emission intensity of In and Ar in plasma and the ratio of the two. In is about 450 nm, A
The luminescence of the peak of about 75 On- was monitored for r. Second
The figure also shows whether there is a glass substrate 3 or a substrate holder 4 on the center of the target 1. Since the plasma state in the space 5 between the stainless steel substrate holder 4 and the target 1 remains constant, the space 5 is
By monitoring the plasma state using the optical head 2, it is possible to always form an ITO film with constant characteristics.

The Ar intensity becomes slightly smaller when the substrate holder 4 is placed above the target 1. Even if the O2 flow rate is controlled so that the ratio of the emission intensities of In and Ar is constant, it is possible to form an ITO film with a more or less constant film quality, although it is slightly oxidized at both ends in the direction of travel.

In magnetron sputtering, a region of high plasma intensity has a donut shape as shown in FIG. Even if the optical head is placed at position 6, the plasma state in space 5 can be substantially monitored, so that an ITO film with constant characteristics can be formed as in the case of position 2.

For comparison, values obtained by monitoring the plasma state in the space 8 using the optical head 7 simultaneously with the optical head 2 are also shown. Although an ITO film of uniform quality is formed on the glass substrate, the emission intensity monitored by the optical head 7 differs when the glass substrate 3 is on the target 1 and when the substrate holder 4 is on the target 1. is thick (changed. This is thought to be because the plasma state in the space 8 has apparently changed significantly. If the optical head 7
When the film is formed while controlling the luminescence intensity of In etc. to be kept constant as monitored by the ITo film, the resulting ITo film is almost transparent at the center of the substrate, but is colored black at both ends in the direction of travel, and remains uncolored even after annealing. It cannot be removed.

In this embodiment, an ITO film has been described, but the present invention can be similarly applied to other transparent conductive films such as a transparent conductive film containing tin oxide as a main component or a transparent conductive film containing cadmium tin oxide as a main component.

The substrate holder 4 was used as a conductive jig to monitor the plasma intensity between the metal target and the conductive jig was fixed between the discharge space 5 and the substrate holder 4, and the conductive jig and the metal target] The same result can be obtained even if the plasma intensity is monitored between the two.It goes without saying that the present invention is also effective in high frequency sputtering.

Effects of the Invention As described above, according to the present invention, it is possible to form a transparent conductive film of uniform quality on a glass substrate at high speed using an in-line sputtering device, and this can be used for electronic devices, etc. It can be widely used as a transparent conductive film and has great practical value.

[Brief explanation of drawings]

FIG. 1 shows a method for manufacturing a transparent conductive film according to the present invention,
(a) is its cross-sectional view, (b) is its plan view, and Figure 2 is
FIG. 3 is a diagram showing changes in the emission intensity of In and Ar in plasma and the ratio thereof during film formation. 1... Target, 2.6.7... Optical head,
3...Glass substrate, 4...Substrate hole goo,
5.8...Discharge space, name of agent Patent attorney Toshio Nakao and one other person

Claims (1)

[Claims] Using a sputtering device that forms a film while moving the substrate, a reactive gas and an inert gas are introduced, and the emission intensity of the plasma generated between the conductive jig and the metal target in the sputtering device is detected. and forming a transparent and conductive compound thin film on the substrate by a reaction between the metal and the reactive gas while controlling variable parameters of the sputtering device using the detected signal. A method for manufacturing a transparent conductive film.