JP2000150466A - Ito dry etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of non-volatile substance for faster etching by, related to dry etching of an indium tin oxide which uses hydrogen iodide gas, allowing a gas linear velocity to be a specific value or above in a specified pressure range between an application electrode which holds a substrate and a counter electrode comprising a gas blowing port. SOLUTION: Related to dry etching for an indium tin oxide(ITO) which uses a gas comprising hydrogen iodide(HI), pressure is 0.1-100 Pa, with high-frequency parallel flat-plate capacitance coupling discharge electrode, an application electrode which holds a substrate with an ITO, and a counter electrode comprising a blowing port which supplies hydrogen iodide provided. A gas linear velocity S/V calculated from a plane formed by connecting periphery of counter application electrode and counter pole, in short the outer circumference area S of inter-electrode space, and a volume flow-rate V in vacuum of a gas comprising the hydrogen iodide released from it is at least 0.8 m/second. Fast etching is performed while non-volatile substance is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for dry etching of ITO. More specifically, the present invention relates to dry etching of indium oxide (hereinafter, referred to as ITO) using hydrogen iodide gas, which enables substantially faster etching than conventional ITO. About the method.

[0002]

2. Description of the Related Art An ITO thin film is also used as a pixel electrode of a liquid crystal display. However, it is necessary to perform patterning in order to arrange the thin film on a predetermined area and position. At present, a wet etching method using an acid such as hydrochloric acid, phosphoric acid, or ferric chloride is used. However, in accordance with a demand for higher definition of a liquid crystal display, a need for further fine processing has arisen. Specifically, when used as a pixel electrode of a liquid crystal display, there are a top ITO method in which ITO is disposed on the upper side as viewed from the TFT and a bottom ITO method in which ITO is disposed on the lower side.

According to the demand for high definition, the processing width is set to 4
μm or less, and to about 1 μm in the near future, but if wet etching is used,
It is not possible to meet such a demand for fine processing. Although a partition of one adjacent pixel is provided, reflection from an adjacent pixel is prevented in this partition. By making the width of this break as small as possible,
As a result, the pixel electrode area can be increased. Therefore, fine processing of etching is required. Also, IT
In the top ITO method in which O is disposed above the TFT, there is a possibility that the metal aluminum wiring layer is corroded in the wet etching method. Therefore, a dry etching method has been used.

[0004] As a problem of wet etching, an etching residue floats and remains on a device. Therefore, it is necessary to change the etchant frequently.
This not only consumes a large amount of etching solution, but also turns them into industrial waste. For the above reasons, wet etching has been conventionally used, but there is a trend to shift to dry etching, and in the future, dry etching will become the mainstream in ITO etching.

[0005] What is used as dry etching is
Using a capacitively coupled 13.56 MHz high frequency power supply,
RIE by placing a substrate on the cathode electrode
(Reactive Ion Etching RIE) method is common. This is because using existing equipment is more economical as a result.

For dry etching, methane (CH
₄ ) A method using a mixed gas of gas and hydrogen (H ₂ ), a method using chlorine (Cl ₂ ) gas, a method using hydrogen bromide (HBr), and the like. However, these methods have problems that the dry etching capability is likely to depend on the apparatus, the range in which good dry etching characteristics can be obtained is narrow, and the dry etching rate is low.

On the other hand, a dry etching method using a hydrogen iodide gas has features such as a small dependence on the apparatus and a high etching rate as compared with the above-mentioned gas system. The dry etching method using hydrogen iodide gas is becoming mainstream. The dry etching of ITO using hydrogen iodide gas is disclosed in Japanese Patent Application Laid-Open No. 8-97190,
It has a good anisotropic shape as fast as 2,000 ° / sec or more. Further, dry etching can be performed without leaving a residue on the substrate.

However, the definition of the etching rate itself is ambiguous, and it is not clear at what point the etching rate is. In other words, it is not clear whether the etching rate is 1000Å / sec or more immediately after the start of dry etching, or the etching rate is 1000Å / sec or more after a sufficient time has elapsed after the etching has proceeded sufficiently. . This is because the dry etching does not start immediately when the etching gas flows and discharge starts, but overlooks that the etching is started after a certain period of time.
In the dry etching of ITO, after the start of discharge, a latent period (Incubati
on Time) exists. Therefore, it is difficult to perform practical dry etching unless it is clear at which point the etching rate is reached.

Further, when dry etching using hydrogen iodide gas is actually performed, no residue is left on the substrate, but by continuing dry etching, a yellow or white nonvolatile nonvolatile material is formed. It comes to adhere to the inner wall of the dry etching apparatus, and eventually inhibits the etching itself. Therefore, after performing dry etching a certain number of times, it is necessary to open the chamber and wipe off the yellow or white non-volatile substance generated and adhered using an alcohol-based volatile chemical. Affects yield.

The identity of the non-volatile substance is also an aggregate of InI ₃ , a compound of indium (In) and iodine (I), and iodine. At the same time, the method for suppressing generation of non-volatile substances (defined as deposits in the presentation) using NF ₃ is also clearly shown. However, this is for suppressing the generation of non-volatile substances, and does not provide any guidance for improving the etching rate of ITO in a substantial aspect.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for performing dry etching of ITO using hydrogen iodide gas in a high speed without generating non-volatile substances generated during dry etching. And to provide a method for performing dry etching.

Liquid crystal display (hereinafter referred to as LCD)
An ITO film used as a display electrode is formed on a substrate such as a glass plate and is patterned by dry etching. The thickness of the ITO film to be used is usually 1000 ° or less, and the initial etching rate is important.

Further, as the etching rate increases, the amount of non-volatile substances increases. This is because the constituent material of the non-volatile substance contains InI ₃ which is a product at the time of dry etching. Therefore, it must be said that it is extremely difficult to improve the etching rate and suppress the generation of non-volatile substances. In order to solve this problem, it was also an object of the present invention to understand the mechanism of dry etching and the mechanism of generation of non-volatile substances.

[0014]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors focused on the flow rate of a gas containing hydrogen iodide gas and changed the flow rate of a gas having a flow rate higher than the conventional flow rate. By supplying from a small hole provided in the counter electrode, while substantially improving the etching rate,
The present inventors have found that it is possible to advance dry etching while minimizing the generation of non-volatile substances, and have completed the present invention.

That is, the present invention relates to (1) hydrogen iodide (H
Indium tin oxide (ITO) using gas containing I)
Dry etching conditions: (a) pressure from 0.1Pa
(B) a device comprising a high-frequency parallel plate capacitively coupled discharge electrode in the range of 100 Pa, an application electrode for holding a substrate with ITO, and a counter electrode having a blowing hole for supplying a gas containing hydrogen iodide. (C) Assuming that a surface formed by connecting the periphery of each of the opposing application electrode and the opposing electrode is the outer peripheral area S of the interelectrode space, the outer peripheral area S of the interelectrode space and iodine released therefrom are used. An ITO dry etching method, wherein a gas linear velocity S / V calculated from a volume flow rate V of the gas containing hydrogen iodide in vacuum is at least 0.8 m / sec, (2) the hydrogen iodide Gas containing hydrogen iodide and at least one of helium, neon, argon, krypton, xenon, and hydrogen
IT according to (1), characterized in that it consists of a kind of gas.
(3) The ITO dry etching method according to (1), wherein the apparatus has a function of maintaining the surface temperature of the inner surface at least 100 ° C.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Non-volatile substances generated in dry etching of ITO using hydrogen iodide gas adhere to the inner wall of the chamber when good dry etching is performed. Hard to adhere to the surface. Therefore, using a parallel plate electrode having the same area shape, a glass plate is set upright on the electrode, and I
When dry etching of TO was performed for about 90 minutes,
The non-volatile material adhered to the vertical glass plate in a manner that describes the shape of the plasma. That is, the non-volatile substance does not adhere to the portion exposed to the plasma, and the non-volatile substance adheres so as to draw an arc outside the plasma region. Considering that the non-volatile substance is not attached to both electrode surfaces, this non-volatile substance was generated and attached outside the plasma.

Further, the non-volatile substance was collected and analyzed for its components. This non-volatile substance is yellow-white,
Some of them have deliquescence, and when exposed to the air, they absorb the moisture in the air and become liquefied. ICP
As a result of qualitative analysis by the (inductively coupled plasma) emission method, it was found that this non-volatile substance contained a large amount of iodine. In addition, metal components such as In (indium), Si (silicon), and Al (aluminum) were also detected. Next, when the non-volatile substance left on the Teflon test piece was analyzed for metal components,
In was the largest component. In comes from components etched from ITO.

Further, the bonding state of this non-volatile substance was analyzed by XPS (X-ray photoelectron spectroscopy).
It was possible to detect the peak of In in a valence state. From the above results, InI ₃ and iodine are basic substances of this nonvolatile substance. ITO advances the etching by evaporating InI ₃ having a high vapor pressure as a product thereof by hydrogen iodide. InI ₃ itself has a high vapor pressure. Conversely, the high vapor pressure of InI ₃
O etching is good.

However, since InI ₃ itself has a high vapor pressure, it is usually difficult to adhere to the inner wall of the chamber as a non-volatile substance. Recalling from the results of the qualitative analysis of ICP that iodine was the most frequently detected, this depot is basically an aggregate of InI ₃ and iodine. That is, inside the plasma, InI ₃ is formed by a reaction with hydrogen iodide on the ITO surface, then evaporates in a two-body structure, and floats as it is. At that point, no coagulation effect due to iodine occurs. However, once
Immediately after deviating from the plasma region, the surrounding iodine radicals adhere by collision, and the adhered iodine acts as a binder to adhere to another InI _3. As a result of increasing its volume, it is observed as a non-volatile substance.

In order to reach a method for suppressing the generation of non-volatile substances, it is necessary to clarify the generation mechanism of non-volatile substances. In general, as for the formation of fine particles in plasma, a group of Watanabe of Kyushu University has been conducting energetic research using silane. In particular, at the 59th Academic Lecture Meeting of the Japan Society of Applied Physics 15a-Q-18, a detailed presentation was made on the growth of fine particles and the method of eliminating them. According to Watanabe et al.'S theory, the mechanism by which silane generates its higher radicals and grows into fine particles is that some higher silanes combine to grow into neutral clusters and be trapped in the cathode sheath. , And further grow into fine particles by the action of van der Waals force or the like. Therefore, by increasing the gas flow rate in the neutral cluster generation region, the neutral clusters are eventually sputtered without growing into fine particles.

Now, a similar growth mechanism is the HI of ITO.
Non-volatile substances generated during etching can also be considered. In other words, what grows from something as a nucleus is a neutral cluster. And this neutral cluster grows further and becomes a non-volatile substance. Then, due to the increase in the gas flow velocity, the neutral cluster does not grow into a non-volatile substance and flows as a neutral cluster or in a state before the neutral cluster.

Clarify what a non-volatile substance is. First, the identity of the non-volatile substance was analyzed and examined, and it was an aggregate of InI ₃ and iodine. Many iodine radicals are generated in hydrogen iodide gas plasma. And this iodine radical is represented by I
It has the property that it can grow rapidly if certain conditions are met, as if accumulation had occurred selectively on the TO surface. Accordingly, as a result of aggregation of iodine radicals having InI ₃ as a nucleus, it is comparable to a neutral cluster having a certain size.

FIG. 1 shows an outline of an apparatus used for etching used in the present invention. The equipment used for the etching test was 1
It is provided with a capacitively coupled parallel flat plate of 0 cmφ. Hydrogen iodide gas is blown out in a shower form from a total of 45 small holes having a diameter of 1 mm and attached to an anode electrode provided on the upper part. On the other hand, an ITO film-formed on a glass substrate is placed on the cathode, and etching is performed by applying plasma.

The execution time of dry etching was basically 2 minutes. This is because the thickness of the ITO is usually 1000 ° or less in the case of a TFT-LCD, and is completed within a very short time of 2 minutes.

The etched film thickness is measured by a stylus film thickness meter (DEKT).
AK-II) was used to measure the level difference from the portion covered with the polyimide tape. The amount of the generated non-volatile substance was determined by measuring the weight change before and after the installation of an aluminum foil (thickness: 15 μm) which was attached to the inner wall of the chamber with an electronic balance. In addition,
A butterfly valve is installed immediately before the turbo molecular pump so that as much hydrogen iodide gas can flow as possible, and the gas in the chamber can be exhausted without giving resistance as much as possible.

As for the dry etching characteristics of ITO using hydrogen iodide gas, there is an incubation period during which dry etching hardly proceeds, as shown in FIG. 2, and thereafter etching proceeds rapidly. By shortening the incubation period, an effective high-speed dry etching of an ITO film having a thin thickness of about 1000 ° can be achieved.

By selecting good dry etching conditions, the incubation period can be reduced to 1 minute or less.
As a result, after 2 minutes, an IT
The O film can be completely removed by etching.

Then, the result of confirming the etching mechanism of ITO will be described. In order to confirm the degree of progress of dry etching by ITO hydrogen iodide gas, the etching time is divided into predetermined times.
At this time, the element attached to the ITO is analyzed by SIMS. The process is performed in the initial state, after 30 seconds, 1 minute, and 3 minutes. These situations are summarized in FIG.

The thickness of the ITO used for the dry etching is 1.2 μm. The detected elements are iodine (I) and indium (In), oxygen (O) and hydrogen (H).
It is. In addition, about I, In, and O, the detected secondary ion intensity is plotted, and the concentration is not specified as an absolute amount. However, as for hydrogen, its ion concentration is required, and the obtained reading multiplied by 10 ¹⁹ becomes the actual concentration. Also,
Separately, the position of the surface is entered according to the etching depth obtained by the stylus film thickness meter.

In the initial state, that is, in the state where etching is not performed, a position having a depth of 0 μm is the surface of the ITO. After 30 seconds from the start of the etching, iodine is accumulated on the ITO surface. But 3
After 0 seconds, the etching has not progressed. Even after a lapse of one minute, although iodine was accumulated, etching was not substantially progressed. However, at three minutes, the etching proceeded, and a thickness of 7000 ° was removed by etching. In addition, the absolute amount of accumulated iodine tended to decrease.

Considering the above, the odor period
In other words, iodine is accumulated on the ITO surface.
Of course, the accumulated iodine and In in ITO
The reaction product InI_ThreeForm
However, during the incubation period, InI _ThreeCan evaporate from the surface
It is in a state that can not be done.

As a result, the lower part of the accumulated iodine layer and the upper layer of ITO participate in the reaction.
Etching is performed only when the generated volatile components evaporate from the surface. In the state where iodine is accumulated, InI ₃ cannot escape from the ITO surface, that is, the etching does not proceed. However, an increase in the pressure inside the storage iodine layer due to the formation of the volatile substance causes the storage iodine layer to evaporate through the storage iodine layer. When this evaporation path is formed,
In addition, the evaporation of InI ₃ is facilitated, further increasing the etching rate.

The etching thickness accelerates with time
, Which means that InI _ThreeFormation speed and
It indicates an increase in the evaporation rate. This is due to the formation of the path
InI_ThreeIncrease the evaporation rate of the water or vice versa
Due to an increase in the reaction area with iodine that has entered. This is Yo
Mechanics of dry etching of ITO with hydrogen iodide gas
Is a rhythm.

The relationship between the hydrogen iodide gas flow rate and the RF output was examined. The conditions used for the study of etching and generation of non-volatile substances are shown below. Etching conditions: Power supply Substrate installation Applied electrode side Frequency 13.56 MHz (RF) RF power 200 W Electrode area 78.5 cm ² Electrode spacing 5 cm Internal pressure 6.7 Pa Gas flow rate Hydrogen iodide gas 10 to 100 sccm Etching time 2 minutes Non-volatile Material generation study conditions Power supply board installation Applied electrode side Frequency 13.56 MHz (RF) RF power 200 W Electrode area 78.5 cm ² Electrode spacing 5 cm Internal pressure 6.7 Pa Gas flow rate Hydrogen iodide gas 10 to 100 sccm Etching time 2 min × 15 times = 30 minutes

FIG. 4 shows the result of the examination.
Shown in In order to improve the etching rate, the improvement of the hydrogen iodide gas flow rate and the improvement of the RF output both show great effects.
This is shown in FIG. 5, where the etching rate is on the Y axis and the hydrogen iodide gas flow rate is on the X axis. Since the etching rates are separately displayed according to the RF output, the etching rates increase as the RF output increases. At the same time, with an increase in the flow rate of the hydrogen iodide gas, the etching rate is improving. Up to a range of 100 sccm, the larger the gas flow rate, the greater the degree of improvement in the etching rate.

This is because the increase in the RF output is proportional to the increase in the flux of the etching species in the plasma. However, an increase in the flux means an increase in the amount reaching the ITO surface or an increase in etching species. However, the etching rate is remarkably improved with an increase in the flow rate of the hydrogen iodide gas, and has another function.

On the other hand, the relationship with the amount of generated non-volatile substances is complicated. FIG. 6 shows the amount of deposited matter on the Y axis and the flow rate of hydrogen iodide gas on the X axis. In the low flow rate region up to 30 sccm, at each RF output, non-volatile material increases in proportion to the increase in flow rate. However, the flow rate of hydrogen iodide gas further increased to 50
Above sccm, the mechanism of non-volatile material generation becomes more complex. For example, at 200 W, the generation amount of the non-volatile substance is reduced at a maximum where the flow rate of the hydrogen iodide gas is 30 sccm. Although the respective tendencies are different, the same tendencies can be confirmed at 150 W and 100 W.

FIG. 7 was prepared in order to show what operating conditions would enable high-speed dry etching while minimizing the generation of non-volatile substances.
FIG. 7 (a) shows the etching rate under each operating condition with the RF output and the hydrogen iodide gas flow rate, which are operating factors, as the Y axis and the X axis, respectively, and a contour line corresponding to the change in the etching rate can be drawn. . Ie RF output,
As the etching rate increases, the etching rate increases. FIG. 7B shows how the amount of generated non-volatile substance is. Also in this case, contour lines can be drawn in accordance with the amount of generated nonvolatile substances. Unlike the case of the etching rate, it is slightly complicated. The increase in the flow rate of the hydrogen iodide gas suppresses the generation of non-volatile substances. In other words, according to these results,
The operating conditions for generating a large amount of nonvolatile substances and the operating conditions for suppressing the generation have been clarified. 7 (a) and 7 (b)
By superimposing, it is possible to confirm at a glance the range in which higher-speed dry etching can be performed while minimizing the generation of nonvolatile substances.

In order to make the conditions for performing the dry etching at a high speed more general while suppressing the non-volatile substances, the conditions will be summarized in consideration of the gas line flow velocity. For example, the size of the electrodes used in this experiment is 10 cmφ, and the electrode spacing is 5 cm. Further, the gas is supplied in a shower form from the anode electrode, and expands and discharges the plasma space from inside to outside. Since the pressure during dry etching is 6.6 Pa, when the flow rate of the hydrogen iodide gas is 70 sccm, the emission linear velocity from the end of the electrode is 1.13 m / sec. This gas linear velocity has a great effect on the effect of suppressing the generation of non-volatile substances, and at the same time enables high-speed dry etching of ITO.

In order to define the linear velocity, an outer peripheral area S of the space between the electrodes is defined. This is the area of the surface formed by connecting the respective periphery of the opposing application electrode and the opposing electrode. FIG. 8 shows some of these examples. FIG. 8 includes an application electrode on the side on which the ITO substrate is installed and a counter electrode provided with a large number of small holes for gas release. This is the area of the surface formed by connecting the outer edges of the counter electrode.

Further, the supplied gas is represented by a volume flow rate V in the pressure state. Usually, a numerical value defined by a gas amount per unit time at 1 atm and 0 ° C. (standard state) is used as the supplied gas. Usually, the flow rate indicated by the standard state gas flow rate per minute is used. Now, assuming that the gas flow rate in the standard state is v sccm, the volume flow rate V required in the present invention can be obtained as V = v × P / 10135, where P is the pressure under given etching conditions. Therefore, the linear velocity when emitted from the space between the electrodes to the outside is V / S. Using the etching apparatus disclosed in the present invention, 70 sccm
When the gas is supplied, the obtained V / S value is 1.13
m / sec.

At a RF output of 200 W and a hydrogen iodide gas flow rate of 70 sccm, the etching thickness in 2 minutes is 1000 °, which is equivalent to the standard thickness of 1000 ° in a TFT-LCD. In the early stage of etching, the required function is sufficiently satisfied. This etching rate is further increased by increasing the RF output value.

As a condition for enabling high-speed dry etching of ITO that can withstand practical use, the V / S value is 0.8 m / sec or more. Further, the upper limit of the V / S value can be determined. Under a low pressure condition in dry etching, the gas flow that can flow while maintaining a given low pressure state is limited by the capacity of an exhaust system. In other words, the condition for suppressing the generation of the non-volatile substance while maintaining the high-speed dry etching of 500 ° / min or more is that the V / S value is 0.8 m / sec or more. Depends on the device performance,
It is desirable to be as large as possible.

Accordingly, FIG. 9 shows the etching rate and the amount of generation of the non-volatile substance obtained when the RF output is 200 W on the S / V value on the X-axis. According to FIG. 9, the S / V value improves the etching rate of ITO from a substantially initial stage while minimizing the generation of non-volatile substances.

The pressure conditions suitable for dry etching of ITO using hydrogen iodide are 0.1 Pa to 0.1 Pa.
It is in the range of 100 Pa. More preferably, it is in the range of 0.5 Pa to 10 Pa. If the pressure is lower than this, the gas itself is mainly exhausted, and a sufficient amount of gas to form a discharge cannot be maintained in the apparatus. Further, under a pressure condition higher than this pressure range, neutral hydrogen iodide which is not dissociated by plasma is mainly used, and the dry etching rate is reduced. In addition, a state in which many non-volatile substances are easily generated is brought.

Further, it is also possible to mix an inert gas such as helium, neon, argon, krypton, or xenon as a gas by mixing with hydrogen iodide gas. Since these can collide with an electrode, particularly a high frequency application electrode, with positive ions, the etching rate of dry etching is improved, and the anisotropic etching performance is further improved.

The mixing of hydrogen gas is also within this range. Hydrogen gas does not have a great effect, but it is not preferable to dilute the hydrogen iodide gas and lower the dry etching performance of the hydrogen iodide gas as a result. A preferred amount is equal to or less than a hydrogen iodide gas equivalent.

However, it is not preferable to mix oxygen. This results in the reduction of trivalent InI ₃ released into the gas phase from ITO as a volatile substance, and as a result,
This results in the formation of InI, which is low in vapor pressure and low in vapor pressure, and results in a residue substance having low volatility.

Further, the frequency applied to the high-frequency electrode is
It is 1 MHz or more and 150 MHz or less. More preferably, it is 5 MHz or more and 80 MHz or less, and most preferably 13.56 MHz or more and 50 MHz or less.
As for the frequency applied to the high-frequency electrode, increasing the frequency improves the amount of radical generation. Therefore, by increasing the frequency, the dry etching rate of ITO can be improved.

In order to increase the volatility of the non-volatile residue, it is desirable for the device to have a function of maintaining its surface temperature at least at 80 ° C. More preferably at least 100 ° C, most preferably at least 15 ° C.
0 ° C. Even if a heating mechanism is not provided, the amount of the residual substance adhered can be significantly reduced by using the conventional methods described in the present invention, but the addition of the heating mechanism makes the effect more effective. But 300
Heating above ℃ is not preferred. This is because when heated to 300 ° C. or more, trivalent InI ₃ is reduced due to thermal energy and is converted to monovalent InI ₃ having a low vapor pressure.

Therefore, the temperature of the inner wall of the apparatus is 80 ° C. or more,
The temperature is preferably 300 ° C or lower, more preferably 100 ° C or higher and 300 ° C or lower. Most preferably, it is 150 ° C. or more and 300 ° C. or less.

[0052]

According to the present invention, an operation method for performing the dry etching of ITO substantially at high speed while minimizing the generation of non-volatile substances in the apparatus in the dry etching of ITO, which has been impossible so far, is provided. Clarified.

[Brief description of the drawings]

FIG. 1 is an outline of a dry etching apparatus used in the present invention.

FIG. 2 is a diagram showing a time dependency of an etching thickness when dry etching of ITO is performed using a hydrogen iodide gas.

FIG. 3 is a diagram in which the depth direction distribution of each element is confirmed by SIMS for each of time-division etchings in order to model the progress of dry etching of ITO. (a) is the result of plotting the ching speed before the start of etching, (b) is the result after 30 seconds,
(c) is the result after 1 minute, and (d) is the result after 3 minutes.

FIG. 4 shows the results when the RF output and the hydrogen iodide gas flow rate were changed using the dry etching apparatus used in the present invention.
FIG. 4 is a diagram plotting a relationship between an etching thickness and a generated amount of a nonvolatile substance.

FIG. 5 is a diagram re-plotted with the etching rate on the Y axis and the hydrogen iodide gas flow rate on the X axis in FIG. 4;

FIG. 6 is a diagram in which the amount of generated nonvolatile matter is plotted on the Y axis and the flow rate of hydrogen iodide gas is plotted on the X axis in FIG. 4;

FIG. 7 shows, in FIG. 4, the hydrogen iodide gas flow rate on the X-axis and the RF output on the Y-axis, (a) a contour line showing the etching rate, and (b) a contour line showing the amount of non-volatile substance generated. FIG.

FIG. 8 shows a surface formed by connecting the periphery of each of the opposing application electrode and the opposing electrode as the outer peripheral area S of the interelectrode space. 3A and 3B are diagrams illustrating a case where the cross-sectional areas are equal to each other and a case where the cross-sectional area of (b) the applied electrode is larger than that of the counter electrode.

FIG. 9 is a diagram showing (a) an etching rate, and (b) a generation amount of a nonvolatile substance, with the S / V value on the X axis.

[Explanation of symbols]

1 Etching chamber 21 High-frequency counter electrode 22 High-frequency application electrode 31 Exhaust system piping 32 Pressure adjustment valve 33 Turbo molecular pump 34 Oil rotary pump 41 Plasma 42 Gas supply piping 43 Gas flow direction 51 Substrate with ITO 52 Insulating substrate (glass plate)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 HA06 JA24 MA08 MA19 NA27 NA29 PA01 4K057 DA20 DB20 DD03 DE01 DE09 DE14 DE15 DE20 DG06 DG07 DM02 DM08 DN02 5F004 AA16 BA04 BB11 BB13 BB18 BB28 DA00 DA04 DA17 DA22 DA23 5 323 CA01

Claims (3)

[Claims] The conditions for dry etching of indium tin oxide (ITO) using a gas containing hydrogen iodide (HI) are as follows: (a) the pressure is in the range of 0.1 Pa to 100 Pa;
(B) using a device consisting of a high-frequency parallel plate capacitively coupled discharge electrode, an application electrode for holding a substrate with ITO, and a counter electrode having a blowing hole for supplying a gas containing hydrogen iodide; Assuming that a surface formed by connecting the respective peripheries of the application electrode and the counter electrode to each other is the outer peripheral area S of the interelectrode space, the outer peripheral area S of the interelectrode space and the gas containing hydrogen iodide released therefrom An ITO dry etching method, wherein a gas linear velocity S / V calculated from a volume flow rate V in a vacuum is at least 0.8 m / sec. 2. The ITO according to claim 1, wherein the gas containing hydrogen iodide comprises hydrogen iodide and at least one of helium, neon, argon, krypton, xenon, and hydrogen. Dry etching method. 3. The apparatus according to claim 1, wherein the temperature of the inner surface is at least 80 ° C.
2. The ITO dry etching method according to claim 1, further comprising a function of maintaining the thickness of the ITO.