JPH06120176A - Method and apparatus of etching - Google Patents

Abstract

PURPOSE:To make it possible to perform an etching with high accuracy and efficiency in a dry method, by performing a low temperature plasma etching using a gas containing a lower hydrocarbon or performing a plasma etching using a mixture gas of lower hydrocarbon and hydrogen. CONSTITUTION:An ITO(indium-titanium oxide) film formed on a glass substrate to a thickness of 2000Angstrom by a sputtering method is etched. A methane gas with a power of 1000W, a pressure of 3X10<-3>Torr and a gas flow rate of 60 SCCM is used and also a low temperature plasma etching at 20 deg.C is performed to a lower electrode. As a result, an etching in a required pattern of the ITO is implemented at an etching rate of 500Angstrom per minute. An accuracy of the pattern is extremely high. In this case, a circular arc electrode whose center part is 0.2mm higher than the other parts is used as the lower electrode. Thus, an etching pattern substrate with a good true flatness can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching method and its apparatus. More specifically, the present invention relates to a new etching method that enables dry etching of an oxide conductive film with high accuracy and high efficiency, and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, a thin film etching method by various methods has been developed as a core elemental technology for manufacturing electronic devices, liquid crystal display devices, etc., and has been put to practical use as a liquid phase method or a vapor phase method. ing. However, in the etching process, it is necessary to carefully select the type of target substance, the accuracy and efficiency of etching, etc., and to select a specific means, so it is not always easy to select that means. . Moreover, in the present circumstances, many problems to be solved remain in the etching methods so far.

As one of these problems, ITO (Indium Tin Oxide), which is becoming more important as a touch panel, an electrode of a liquid crystal color filter, etc.,
That is, dry (gas phase) etching of a transparent oxide conductive film such as tin oxide has not been established as a practically satisfactory technique. This oxide conductive film is actually subjected to liquid phase etching using an acid, and its accuracy and efficiency are limited, and the etching rate is at most 200 Å / min. Further, this liquid phase method also has a problem in terms of post-treatment of the treatment liquid. Therefore, realization of etching by a dry method has been strongly desired.

Of course, a dry method has also been studied for the dry etching of ITO and the like. For example, plasma etching with an inert gas such as argon or helium, or one using an etching agent of a mixed gas obtained by adding alcohol such as methanol to this inert gas has been proposed. But these methods also
The reality was that we could not be satisfied in terms of practical accuracy and efficiency.

The present invention has been made in view of the above circumstances, solves the drawbacks of the conventional method for etching an oxide conductive film, and achieves high accuracy in a dry (gas phase) system.
It is an object of the present invention to provide a new etching method for an oxide conductive film and a device therefor, which enables highly efficient etching.

[0006]

In order to solve the above problems, the present invention provides a method for etching an oxide conductive film, which comprises performing low temperature plasma etching with a lower hydrocarbon-containing gas. Further, the present invention is
Plasma etching with a mixed gas of a lower hydrocarbon and a hydrogen gas is also one of its modes.

Explaining in more detail, first, as the oxide conductive film targeted by the present invention, the above-mentioned I
Various materials such as TO (indium tin oxide) and tin oxide are exemplified, and these conductive films can be formed on various substrates such as glass, ceramics and polymer files. . Usually, these conductive films can be formed with a thickness of about 500 to 3000 Å.
1500 with a resistance value of 20 Ω / unit area
It is possible to target a thing of about 1800Å.

For low temperature plasma etching, lower hydrocarbons as described above, more preferably saturated hydrocarbons having about 1 to 4 carbon atoms, for example, lower hydrocarbons such as methane, ethane, propane, butane and isobutane are suitable. , And these can be used alone or in a mixed state. In this case, unsaturated hydrocarbons such as ethylene and propylene may be used or mixed.

The lower hydrocarbon can be used alone or diluted with an inert gas such as argon or helium. The proportion of lower hydrocarbons in this case can be set in an appropriate range of, for example, about 1 to 50 vol%. It is also effective to use hydrogen gas mixed with these lower hydrocarbons for etching. In this case, the mixing ratio is 1: 0.1 as a molar ratio.
It can be about 1: 5. Of course, it goes without saying that these numerical values are only a guideline and can be changed.

In plasma etching, the pressure in the etching reaction region is 1 × 10 ⁻⁴ in a vacuum-exhausted reactor.
It is carried out in the state of glow plasma by low temperature plasma discharge in the range of about 1 × 10 ^-2 Torr. At this time, the substrate may be appropriately heated by a heater or the like.
Various types and structures can be adopted as the reactor for this etching, but more preferably, for example, the parallel plate type illustrated in FIGS. 1 and 2 can be used.

The apparatus illustrated in the perspective view of FIG. 1 and the cross-sectional view of FIG. 2 includes a substrate (1) including a supply section (2) having an elevator mechanism built therein, an etching reaction section (3) and an extraction section (4). Comprised of areas, etching reaction part (3)
Has an upper electrode (31), a lower electrode (32), a quartz cover (33), for example, a substrate holder (34) made of alumina, and the like, and the upper electrode (31) is a lid (35) that can be opened and closed. It is fixed inside, and the lower electrode (32) is fixed and supported by an insulator (36) such as Teflon.

The substrate retainer (34) is allowed to move up and down, and the etching gas is used for the upper electrode (3
1) side is supplied to the reaction zone. In such a device, the lower electrode (32) is centered at 0.
It is also effective to make it arc-shaped with a height of about 2 to 0.3 mm. For example, in a glass substrate, this is an effective means for ensuring the true flatness of the substrate after etching is completed.

Needless to say, the etching method of the present invention can have various modes. Hereinafter, the present invention will be described in more detail with reference to examples.

[0014]

Example 1 Using the apparatus illustrated in FIGS. 1 and 2, an ITO (indium tin oxide) film having a thickness of 2000 Å formed on a glass substrate by a sputtering method was etched.

1000 W power, 3 × 10 ⁻³ Torr pressure,
Methane gas with a gas flow rate of 60 SCCM was used, and the lower electrode was subjected to low temperature plasma etching at a temperature of 20 ° C. As a result, at an etching rate of 500Å / min, I
Etching with the required pattern of TO was realized. The pattern accuracy was extremely good.

In this case, as the lower electrode. An arc-shaped electrode whose center is 0.2 mm higher was used. An etching pattern substrate having excellent flatness was obtained. Example 2 In line with Example 1, methane: H ₂ (molar ratio) = 1: 0.5
, And methane: H ₂ (molar ratio) = 1: 1 were used for etching. Etching of ITO was realized at an etching rate of 600 to 700Å / min.

The etching pattern was very good. Example 3 Using a mixed gas of methane: ethane: H ₂ (molar ratio) = 1: 0.5 and methane: ethane: H ₂ (molar ratio) = 1: 1: 2 while raising the substrate temperature to 60 ° C. Etching was performed. High-precision etching was achieved at a speed of 550 to 600Å / min.

Example 4 Example 1 was realized by mixing methane with argon. The proportion of methane in this case was 20 vol%. The gas flow rate was 80 SCCM. Etching was possible at a rate of 650Å / min.

[0019]

As described in detail above, according to the present invention, highly accurate and highly efficient etching of an oxide conductive film is realized by a dry method. It will lead the future development of dry etching of conductive films.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a device of the present invention.

FIG. 2 is a sectional view corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Supply part 3 Etching reaction part 4 Extraction part 31 Upper electrode 32 Lower electrode 33 Quartz cover 34 Substrate retainer 35 Lid part 36 Insulator

Claims (7)

[Claims] 1. A method for etching an oxide conductive film, which comprises low-temperature plasma etching with a lower hydrocarbon-containing gas. 2. A method for etching an oxide conductive film, which comprises performing a lower plasma etching with a gas containing a lower hydrocarbon and hydrogen. 3. A method for etching an ITO film according to claim 1 or 2. 4. The etching method according to claim 1, wherein the etching is performed with a gas containing methane and / or ethane. 5. In a parallel plate type plasma device having an upper electrode and a lower electrode, the upper electrode is arranged on an inner side surface of the opening / closing lid, and a substrate retainer is arranged on a side portion of the lower electrode, and a reaction is performed. A plasma etching apparatus characterized in that a substrate supply unit and a substrate extraction unit are respectively provided on the left and right sides of the region, and the reaction gas is supplied from the upper electrode side. 6. The etching apparatus according to claim 1, wherein the substrate mounting surface of the lower electrode has an arc shape. 7. A glass substrate I according to claim 6 or 7.
TO film etching equipment.