JP4764313B2 - Durability evaluation method of aluminum alloy electrode - Google Patents

Description

  The present invention belongs to a technical field related to a method for evaluating the durability of an aluminum alloy electrode, and particularly relates to a technical field related to a method for evaluating the durability of an anodized aluminum alloy electrode used in a dry etching apparatus for semiconductors and liquid crystals. It is.

  In a semiconductor or liquid crystal dry etching apparatus, an anodized aluminum alloy electrode (upper electrode, lower electrode) subjected to anodizing treatment to generate plasma is exposed to chlorine-based gas plasma, and the temperature is a maximum of 200 ° C. Furthermore, since it is exposed to hydrochloric acid generated from the plasma component adhering to the electrode when wiping with water for maintenance, it deteriorates with use, particularly when the use temperature is 120 to 200 ° C.

As a result, the function as an electrode is impaired, and any one of the following problems (1) to (4) or two or more problems occur, resulting in the life of the electrode.
(1) A predetermined etching shape is not obtained.
(2) A predetermined etching rate is not achieved.
(3) Etching shape and etching rate (hereinafter also referred to as etching characteristics) vary in the processing substrate (wafer or glass substrate) surface.
(4) The corrosion product of the electrode becomes dust and contaminates the processing substrate.

  When the life of the electrode is determined by the above problems (1), (2), and (4), this is a problem of durability of the entire anodized material.

Therefore, various methods have been proposed for extending the life of the electrode, that is, for improving the durability. In that case, the following evaluation tests (A) to (C) are carried out as durability evaluation test methods, and it is possible to predict the durability comparison with the current material in advance without actually using it.
(A) A material is directly irradiated with plasma to evaluate the amount of wear and damage of the material (see, for example, Japanese Patent No. 2900822, Japanese Patent No. 2944934, and Japanese Patent No. 2900820). Hereinafter, this evaluation test is also referred to as a plasma irradiation test.
(B) Corrosion state is evaluated by exposing a corrosive gas to a material at a high temperature (see, for example, Japanese Patent No. 2900822, Japanese Patent No. 2936334, Japanese Patent No. 2900820). Hereinafter, this evaluation test is also referred to as a hot gas corrosion test.
(C) The material is immersed in an acid to evaluate the corrosion state (see, for example, JP-A-2003-34894 and JP-A-2004-225113). Hereinafter, this evaluation test is also referred to as an acid immersion test.

  On the other hand, when the life of the electrode is limited by the above-mentioned problem (3), there is a problem of variation in the state of the anodized material in one electrode, that is, a part with good durability and a bad part are mixed. It is caused by doing.

  The reason why this durable part and the bad part coexist is that the distribution of the material state of the base aluminum alloy (composition distribution, composition of crystallized substances and precipitates, size distribution, crystal grain shape and size, etc. ), Temperature distribution on the surface of the non-treated material during anodization (due to the set temperature of the treatment liquid, circulation method, etc.), distribution of the treatment solution composition on the treated surface (due to the treatment liquid circulation method) Electrode manufacturing conditions and management methods such as washing variation during water washing and drying variation during drying are affected.

When the manufacturing conditions of the above electrode are controlled to improve the life, the evaluation test for confirming the effect is that a plurality of pieces are cut out from the electrode and the above-mentioned plasma irradiation test and high temperature gas are performed on each piece. There is a method of performing a corrosion test and an acid immersion test and comparing the corrosion resistance between pieces, and obtaining a result that there is a difference in corrosion resistance between pieces in the current material, but no difference in the improved material. However, it is difficult to detect the difference in the local material state in the electrode surface. In the plasma irradiation test, the high temperature gas corrosion test, and the acid immersion test, the processing substrate having the etching characteristics (etching shape and etching rate) is used. In some cases, in-plane variation cannot be detected. Therefore, at present, the effect of improvement is confirmed by actual use, and the appearance of an evaluation test method that can confirm the effect of improvement without actual use is desired.
Japanese Patent No. 2900822 Japanese Patent No.2943634 Japanese Patent No. 2900820 Japanese Patent Laid-Open No. 2003-34894 JP 2004-225113 A

  The present invention has been made by paying attention to such a situation, and the purpose thereof is to treat an anodized aluminum alloy electrode used in a dry etching apparatus with an etching characteristic (etching shape and etching rate). An object of the present invention is to provide an aluminum alloy electrode durability evaluation method capable of predicting the difficulty of occurrence of in-plane variation (whether or not variation is likely to occur) without actually using the aluminum alloy electrode. It is.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. According to the present invention, the above object can be achieved.

  The present invention thus completed and capable of achieving the above object relates to a method for evaluating the durability of an aluminum alloy electrode. The durability evaluation of an aluminum alloy electrode according to claims 1 to 5 of the claims. It is a method and has the following configuration.

  That is, the durability evaluation method for an aluminum alloy electrode according to claim 1 is a durability evaluation method for an aluminum alloy electrode subjected to an anodizing treatment used in a dry etching apparatus, wherein the electrode is heated at a temperature of 120 to 200 ° C. The aluminum alloy electrode durability evaluation method is characterized by measuring the dispersion of leakage current distribution on the surface of the electrode after being held for 1 hour or longer and then immersed in a hydrochloric acid aqueous solution, and then measuring the variation in leakage current distribution on the electrode surface [first invention].

  The durability evaluation method for an aluminum alloy electrode according to claim 2 is the durability evaluation method for an aluminum alloy electrode according to claim 1, wherein the temperature of the aqueous hydrochloric acid solution is 10 ° C. or higher [second invention]. The durability evaluation method for an aluminum alloy electrode according to claim 3 is the durability evaluation method for an aluminum alloy electrode according to claim 1 or 2, wherein the temperature of the aqueous hydrochloric acid solution is 40 ° C. or lower [third invention].

  The durability evaluation method for an aluminum alloy electrode according to claim 4 is a method for evaluating the durability of an aluminum alloy electrode according to any one of claims 1 to 3, wherein the concentration of the hydrochloric acid aqueous solution is 0.1 mass% or more. There is [fourth invention]. The durability evaluation method for an aluminum alloy electrode according to claim 5 is the durability evaluation method for an aluminum alloy electrode according to any one of claims 1 to 4, wherein the concentration of the aqueous hydrochloric acid solution is 10% by mass or less. Fifth invention].

  According to the durability evaluation method for an aluminum alloy electrode according to the present invention, the variation in etching characteristics (etching shape and etching rate) within the surface of the processed substrate is observed for the anodized aluminum alloy electrode used in the dry etching apparatus. It becomes possible to predict the difficulty of generation (whether or not it is easy to generate variation) without actually using the aluminum alloy electrode.

  Since dry etching is performed using plasma, the etching shape and the etching rate (etching characteristics) are affected by the state of the plasma. That is, the reason why the dry etching shape and the etching rate vary within the processing substrate surface is that the plasma state varies within the processing substrate surface. Since the plasma is generated by applying a voltage between the electrodes, the variation in the plasma state is due to the variation in the electrical characteristics of the material in the electrode surface. Therefore, it was considered that the etching characteristics varied in the processing substrate surface because the electrical characteristics of the material in the electrode surface varied.

  Therefore, the electrical characteristics of the electrodes when the dry etching shape and the etching rate varied within the processing substrate surface were investigated. As a result, it was found that the leakage current on the electrode surface varied within the electrode surface.

  Furthermore, all of the new electrodes have no variation in the leakage current of the electrode surface within the electrode surface, and there is no variation in the etching shape and etching rate within the processing substrate surface, but the dry etching shape and etching rate processing substrate surface We examined electrodes that have a difference in use time until the occurrence of variation in the inside. As a result, it was found that the difference between the electrodes can be reproduced by heating the electrodes and then immersing them in an aqueous hydrochloric acid solution (hereinafter also referred to as hydrochloric acid). That is, for a new electrode heated and then immersed in hydrochloric acid, the variation in the leakage current on the electrode surface within the electrode surface was measured, and as a result, the variation in the leakage current on the electrode surface within the electrode surface was observed. It was found that the longer the use time until the variation in the dry etching shape and the etching rate within the surface of the processing substrate occurs, the longer the time.

  That is, it was found that the environment in which the electrode is used can be simulated by heating the electrode and then immersing it in hydrochloric acid. Then, after heating the electrode, by measuring the time until the occurrence of variation in the leakage current on the electrode surface within the electrode surface of the sample immersed in hydrochloric acid, the variation in etching characteristics within the treated substrate surface is caused. It was found that difficulty (whether it is easy to cause variation or not) can be predicted without actually using the electrode.

  Here, the difference between the electrodes cannot be reproduced simply by heating the electrodes, and the difference between the electrodes cannot be reproduced simply by soaking in hydrochloric acid. The difference between the electrodes can be reproduced, and the point is to simulate the use environment by immersing in hydrochloric acid after heating the electrodes.

  This indicates that the anodized aluminum alloy changes its hydrochloric acid resistance once heated. The mechanism of this phenomenon is unknown, and is under intensive analysis.

  In addition, the mechanism that can simulate the operating environment of the actual machine by immersing the electrode in hydrochloric acid after heating the electrode has not been elucidated, but the electrode operating temperature is simulated by heating, and the electrode is exposed to chlorine-based gas plasma by immersing in hydrochloric acid. I think that it can simulate the exposure to hydrochloric acid during maintenance.

  As described above, the environment of use can be simulated by heating the electrodes and then immersing them in hydrochloric acid, and the difference between the electrodes can be reproduced. That is, after the electrode is heated, it is immersed in hydrochloric acid, and if it is examined whether it is difficult to cause variations in the leakage current of the electrode surface within the electrode surface (whether or not the variation is likely to occur), It can be seen that it is difficult to cause variations in etching characteristics within the processing substrate surface (whether or not it is easy to cause variations).

  At this time, when heating the electrode, it is necessary to hold at a temperature of 120 to 200 ° C. for at least 1 hour.

  Therefore, the durability evaluation method for an aluminum alloy electrode according to the present invention is a durability evaluation method for an aluminum alloy electrode subjected to an anodizing treatment used in a dry etching apparatus, and the electrode is heated at a temperature of 120 to 200 ° C. The aluminum alloy electrode durability evaluation method is characterized by measuring the dispersion of the leakage current distribution on the surface of the electrode after dipping in an aqueous hydrochloric acid solution (hydrochloric acid) after holding for more than an hour, and then measuring the variation in leakage current distribution on the electrode surface.

  As can be seen from the above, according to the durability evaluation method for an aluminum alloy electrode according to the present invention, the etching characteristics (etching shape and etching rate) of the anodized aluminum alloy electrode used in the dry etching apparatus are It is possible to predict the difficulty of occurrence of variation within the surface of the processing substrate (whether or not variation is likely to occur) without actually using the aluminum alloy electrode.

  In the durability evaluation method for an aluminum alloy electrode according to the present invention, the holding temperature (heating temperature) of the electrode before immersion in hydrochloric acid is 120 to 200 ° C. This is because the change cannot be reproduced, while if it exceeds 200 ° C., the actual use behavior may not be simulated. When the heating temperature is in the range of 120 to 200 ° C. and the electrode operating temperature or higher, the actual usage status can be simulated more rapidly.

  The reason why the holding time (heating time) of the electrode is set to 1 hour or longer is that if it is less than 1 hour, the use environment cannot be simulated. If the heating time is too long, the evaluation test workability deteriorates, so the heating time is preferably in the range of 1 hour or more and shorter. One hour is enough. The heating environment is not particularly limited and may be in a simple atmosphere.

  When the electrode is held at 120 to 200 ° C. for 1 hour or more and then immersed in hydrochloric acid, the temperature and concentration of the hydrochloric acid and the time of immersion in hydrochloric acid (hereinafter referred to as hydrochloric acid immersion time) are not particularly limited. These may be set as appropriate. That is, when the hydrochloric acid temperature is low and / or the hydrochloric acid concentration is low, the hydrochloric acid immersion time is lengthened. On the other hand, when the hydrochloric acid aqueous solution temperature is high and / or the hydrochloric acid concentration is high, The hydrochloric acid immersion time may be shortened.

  When the temperature of hydrochloric acid is less than 10 ° C., the progress of the reaction is slow, and therefore it is necessary to lengthen the hydrochloric acid immersion time. From the viewpoint of shortening the hydrochloric acid immersion time, the temperature of hydrochloric acid is preferably 10 ° C. or higher [second invention]. When the temperature of hydrochloric acid exceeds 40 ° C., corrosion (pitting corrosion) tends to occur, and the change of the anodic oxide film that occurs in actual use tends to be difficult to reproduce. From the viewpoint of this suppression, the temperature of hydrochloric acid is desirably 40 ° C. or lower [third invention].

  When the concentration of hydrochloric acid is less than 0.1% by mass, the progress of the reaction is slow, and therefore it is necessary to lengthen the hydrochloric acid immersion time. From the viewpoint of shortening the hydrochloric acid immersion time, the concentration of hydrochloric acid is preferably 0.1% by mass or more [fourth invention]. When the concentration of hydrochloric acid exceeds 10% by mass, corrosion (pitting corrosion) is likely to occur, and it becomes difficult to reproduce changes in the anodized film that occur in actual use. From the viewpoint of this suppression, the concentration of hydrochloric acid is preferably 10% by mass or less [fifth invention]. The concentration of hydrochloric acid (hydrochloric acid aqueous solution) refers to the concentration (mass%) of HCl in the aqueous hydrochloric acid solution. That is, [amount (mass) of HCl in hydrochloric acid aqueous solution / amount (mass) of aqueous hydrochloric acid] × 100 = concentration (mass%) of the aqueous hydrochloric acid solution.

  When the temperature of hydrochloric acid is less than 10 ° C. and the concentration of hydrochloric acid is less than 0.1% by mass, the immersion time of hydrochloric acid needs to exceed 10 minutes. For this reason, the efficiency of the durability evaluation test (number of tests / hour ) Is low. From the viewpoint of improving efficiency, it is desirable that the hydrochloric acid temperature is 10 ° C. or higher and the hydrochloric acid concentration is 0.1 mass% or higher.

  When the temperature of hydrochloric acid exceeds 40 ° C. and the concentration of hydrochloric acid exceeds 10% by mass, corrosion (pitting corrosion) is likely to occur, and in order to prevent this, the hydrochloric acid immersion time needs to be less than 30 seconds. The evaluation test work must be performed quickly, and it is difficult, and the measurement accuracy may be lowered due to the large influence of the difference in hydrochloric acid immersion time. In view of this improvement, it is desirable that the hydrochloric acid temperature is 40 ° C. or lower and the hydrochloric acid concentration is 10 mass% or lower.

  The present invention is implemented in the following manner. First, the anodized aluminum alloy electrode is heated. Alternatively, this electrode is divided into pieces and then heated. At this time, heating temperature shall be 120-200 degreeC. The heating time is 1 hour or longer.

  After the electrode (or piece) is heated, it is immersed in hydrochloric acid. Usually, the electrode (or piece) is cooled to room temperature and then immersed in hydrochloric acid. If it is below the temperature of hydrochloric acid, it may be immersed in hydrochloric acid when it is not cooled to room temperature, but it is better to immerse it in hydrochloric acid when it is cooled below the temperature of hydrochloric acid. Is more preferable, and the measurement accuracy is more stable.

  After the electrode (or piece) is immersed in the hydrochloric acid, the leakage current on the electrode surface is measured, and the distribution of the leakage current on the electrode surface in the electrode surface is determined. That is, the variation in leakage current on the electrode surface within the electrode surface is obtained. After the electrode (or piece) is immersed in hydrochloric acid, it is usually washed with water and dried, and then the leakage current on the electrode surface is measured.

  An example of the measurement method and measurement conditions of the leakage current on the electrode surface will be described below. Since an anodized aluminum alloy (an anodized aluminum alloy electrode) has a highly electrically insulating surface coating, a terminal is formed of a conductive material on the surface. As the material of this terminal, stable gold is preferable, and it is formed by vapor deposition or sputtering. In this case, the distribution of the leakage current in the electrode plane cannot be measured unless an independent terminal is used for each measurement point.

  The connection between the terminal and the measuring instrument is made with a probe attached to the end of the conducting wire from the measuring instrument. The shape of the probe may be arbitrary, but a needle-type probe is suitable for reliably contacting the terminal and measuring with good reproducibility.

  Specifically, for example, as shown in FIG. 13, the terminal produced on the surface of the anodized film is connected to the positive electrode of the measuring device, and the aluminum alloy substrate of the electrode is connected to the negative electrode of the measuring device. For example, a screw is screwed in from the aluminum alloy substrate side, and the screw is sandwiched between clips at the end of the lead wire from the measuring instrument. Since the terminals on the surface of the anodized film and the aluminum alloy are electrically conductive, a voltage is applied between the surface of the anodized film and the aluminum alloy substrate interface, and the current (leakage current) flowing between them is measured. become.

  The leakage current measurement voltage (the voltage between the aluminum alloy substrate and the surface of the anodized film) may be set as appropriate. However, since an anodized aluminum alloy causes dielectric breakdown, the dielectric breakdown voltage is measured in advance. The voltage is lower than that.

  The leakage current (current flowing between the aluminum alloy substrate and the anodized film surface) is, for example, several μA to several mA for an anodized aluminum alloy, so use a measuring instrument that can measure it. To do. Although the number of measurement points of the leakage current is preferably as many as possible, it is appropriately set according to the size of the electrode.

  The leakage current on the electrode surface is measured by such a measurement method or measurement condition.

  Examples of the present invention and comparative examples will be described below. The present invention is not limited to this embodiment, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which are within the technical scope of the present invention. include.

[Example 1]
The following two types of aluminum alloy electrodes (anodized aluminum alloy electrodes) are used as electrodes (900 mm x 700 mm) corresponding to the lower electrode (anodized aluminum alloy electrodes) for liquid crystal dry etching equipment. Produced. That is, when anodizing an aluminum alloy electrode, the number of nozzles for bubbling the anodizing solution is set to a normal number (n: 4), and an electrode obtained by anodizing (hereinafter referred to as electrode 1) Then, the number of nozzles for bubbling the anodizing solution was reduced to half of n (n / 2: 2), and an electrode obtained by anodizing (hereinafter referred to as electrode 2) was produced. The anodic oxidation treatment was carried out by a normal method except for the number of bubbling nozzles when the electrode 2 was produced.

  Liquid crystal dry etching was performed using the electrodes 1 and 2 thus fabricated. At this time, the temperature during dry etching was set to 130 ° C. Dry etching was performed until the etching rate of the liquid crystal glass substrate surface varied. That is, dry etching was performed until the uniformity of the etching rate exceeded a specified value (± 5%). The number of glass substrate treatments (dry etching treatments) up to that time was defined as the electrode life.

  As a result, the electrode 2 had a lifetime (durability) of 1/6 that of the electrode 1. This is because the electrode 1 and the electrode 2 are different in the number of nozzles for bubbling the anodizing solution during the preparation (anodizing treatment). This is thought to be due to the increased variation in the state of the

[Example 2]
Ten pieces (50 × 50 mm) were cut out from the above-described electrodes 1 and 2 (one that was not used for dry etching after preparation (anodizing treatment)), and the leakage current of each piece was measured.

  At this time, prior to the measurement of the leakage current, gold having a diameter of 3 mm and a thickness of 0.5 μm was formed as a terminal on the surface of the anodized film of each piece by sputtering. One terminal was used per piece. As a conducting wire for connecting the terminal and the measuring instrument, a tungsten needle probe having a tip of φ500 μm was used, and the probe was brought into contact with the terminal. When measuring the leakage current, the voltage (voltage between the aluminum alloy substrate of the electrode piece and the anodized film surface) was applied from 0 to 1000 V at 2 V / second, and the current at 1000 V (the aluminum alloy of the electrode piece) The current flowing between the substrate and the anodized film surface was measured. This current is a leakage current at a voltage of 1000V.

  The measurement result of said leakage current is shown in FIG. In addition, (1) of FIG. 1 shows the result about the electrode 1 (piece), and (2) of FIG. 1 shows the result about the electrode 2 (piece). That is, the left figure shows the result for the electrode 1 (piece), and the right figure shows the result for the electrode 2 (piece). As shown in FIG. 1, the variation in leakage current in the new state was the same between the electrode 1 and the electrode 2, and the difference in durability between the electrode 1 and the electrode 2 could not be determined.

[Example 3]
Ten pieces (50 × 50 mm) were cut out from the above-mentioned electrodes 1 to 2 and were new (hereinafter also referred to as new electrodes 1 and 2), heated in air at 140 ° C. for 1 hour, and then air-cooled. . And about this piece after this air cooling, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement result of this leakage current is shown in FIG. 2 shows the result for the electrode 1 (piece), and FIG. 2 (2) shows the result for the electrode 2 (piece). As shown in FIG. 2, the leakage current was smaller as a whole than in the case of a new electrode, but the variation in leakage current was about the same between electrode 1 (piece) and electrode 2 (piece). The difference in durability between the electrode 2 and the electrode 2 could not be determined.

[Example 4]
Pieces (50 × 50 mm) were cut out from the new electrodes 1-2, immersed in a 1% by mass aqueous hydrochloric acid solution at 25 ° C. for 2 to 20 minutes (10 pieces each), and then washed with water. And about this piece after this water washing, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement result of this leakage current is shown in FIG. Note that (1-1), (1-2), (1-3), and (1-4) in FIG. 3 show the results for the electrode 1 (piece). ), (2-2), (2-3), and (2-4) show the results for the electrode 2 (piece). That is, the left figure in the figure shows the result for the electrode 1 (piece), and the right figure shows the result for the electrode 2 (piece) (the same applies to the following figures). As shown in FIG. 3, the leakage current increased as a whole as compared with the case of a new electrode, but the variation in leakage current was about the same between the electrode 1 (piece) and the electrode 2 (piece). The difference in durability between electrode 1 and electrode 2 could not be determined.

[Example 5]
A piece (50 × 50 mm) is cut out from the new electrodes 1 and 2 and heated in the atmosphere at 140 ° C. for 1 hour, then air-cooled, and then in a 1% by mass hydrochloric acid aqueous solution at 25 ° C. for 5 minutes. Or it was immersed for 10 minutes (each 10 pieces), and then washed with water. And about this piece after this water washing, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement result of this leakage current is shown in FIG. When heated and immersed in aqueous hydrochloric acid as described above, the variation in leakage current is larger at electrode 2 (piece) than at electrode 1 (piece), and the difference in durability between electrode 1 and electrode 2 can be detected. It was.

[Example 6]
The piece after immersion for 10 minutes in the aqueous hydrochloric acid in Example 5 and washing with water is hereinafter referred to as piece A. In this piece A, what is obtained from the electrode 1 is referred to as piece A-1, and what is obtained from the electrode 2 is referred to as piece A-2.

  About the said new electrodes 1-2 and the piece A, the surface state of the film | membrane was observed with the optical microscope (light microscope). The result is shown in FIG. FIG. 12A is a drawing-substituting photograph showing a micrograph of the surface of piece A-1. FIG. 12B is a drawing-substituting photograph showing a micrograph of the surface of the piece A-2. As can be seen from these figures, in the optical microscope, no difference was observed between the surface states of piece A-1 and piece A-2. That is, the difference in the film state between the electrode 1 and the electrode 2 could not be judged with the optical microscope. Thus, although the conventional evaluation method cannot detect the difference in durability between the electrode 1 and the electrode 2, the method in Example 5 can detect the difference in durability between the electrode 1 and the electrode 2. The method of Example 5 is a method according to the present invention. Therefore, it was confirmed that the present invention can detect a difference in durability that cannot be detected by the conventional evaluation method.

[Example 7]
A piece (50 × 50 mm) is cut out from the new electrodes 1-2, heated in the atmosphere at 110 ° C. to 210 ° C. for 1 hour, then air-cooled, and then in a hydrochloric acid aqueous solution having a concentration of 1% by mass at 25 ° C. For 10 minutes (10 pieces each), and then washed with water. And about this piece after this water washing, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement results of this leakage current are shown in FIGS. The results of Example 4 (not heated) and Example 5 (heating temperature 140 ° C.) are also shown in FIGS. As can be seen from FIGS. 5 to 6, in the above pieces, the heating temperature (heating temperature) of 110 ° C. showed the same tendency as in Example 4 (not heated), and the heating effect was There wasn't. When the heating temperature was 120 ° C. to 200 ° C., a difference in durability between the electrode 1 and the electrode 2 could be detected.

  When the heating temperature was 210 ° C., the leakage current varied even with the electrode 1, and a difference in durability between the electrode 1 and the electrode 2 could not be detected. When the surface of the test piece is observed with an optical microscope, a large crack that does not occur in the actual machine (when used for the lower electrode of the dry etching apparatus) is observed, and it is considered that the leakage current varies due to this.

[Example 8]
A piece (50 × 50 mm) is cut out from the new electrodes 1 and 2 and heated in the atmosphere at 140 ° C. for 0 to 1 hour, then air-cooled, and then in a hydrochloric acid aqueous solution having a concentration of 1% by mass at 25 ° C. It was immersed for 10 minutes (each 10 pieces) and then washed with water. And about this piece after this water washing, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement result of this leakage current is shown in FIG. The results of Example 4 (not heated) and Example 5 (heating time 1 hour) are also shown in FIG. As can be seen from FIG. 7, no difference in durability between the electrode 1 and the electrode 2 was detected when the piece was heated for 45 minutes (heating time). When the heating time is 45 minutes, the heating time is insufficient. When the heating time was 1 hour, a difference in durability between the electrode 1 and the electrode 2 could be detected.

[Example 9]
A piece (50 × 50 mm) is cut out from the new electrodes 1 and 2 and heated in air at 140 ° C. for 1 hour, then air-cooled, and then 0.08 to 0.1% by mass of 9 to 10 ° C. It was immersed in a hydrochloric acid solution having a concentration for 9 to 12 minutes (each 10 pieces) and then washed with water. And about this piece after this water washing, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement results of this leakage current are shown in FIGS. In these figures, the horizontal axis is leakage current (μA) and the vertical axis is frequency (point), but this illustration is omitted (the same applies to FIGS. 10 to 11 below). As can be seen from FIGS. 8 to 9, in the case of immersion in a 0.1 mass% hydrochloric acid aqueous solution at 10 ° C., a difference in durability between the electrodes 1 and 2 could be detected by immersion for 9 minutes. In the case of immersion in a 0.08 mass% hydrochloric acid aqueous solution at 10 ° C., the difference in durability between the electrode 1 and the electrode 2 cannot be detected in the immersion for 10 minutes, and the electrode 1 and the electrode 1 in the immersion for 12 minutes exceeding 10 minutes. Since the difference in durability of the electrode 2 could be detected and it took more than 10 minutes, the evaluation test efficiency was poor. In the case of immersion in a 0.1% by mass hydrochloric acid aqueous solution at 9 ° C., the difference in durability between the electrode 1 and the electrode 2 cannot be detected by immersion for 10 minutes, and the electrode 1 and the electrode can be detected by immersion for more than 10 minutes for 12 minutes. The difference in durability between the two was detected, and it took more than 10 minutes, so the evaluation test efficiency was poor. In the case of immersion in a 0.08 mass% hydrochloric acid aqueous solution at 9 ° C., the difference in durability between the electrode 1 and the electrode 2 cannot be detected by immersion for 10 minutes, and the electrode 1 and the electrode can be detected by immersion for 20 minutes exceeding 10 minutes. The difference in durability between the two was detected, and it took more than 10 minutes, so the evaluation test efficiency was poor.

  Those having an immersion time of more than 10 minutes have poor evaluation test efficiency (number of tests / hour), so it is desirable to use a hydrochloric acid aqueous solution having a concentration of 10% or more and 0.1% by mass that can be evaluated by immersion within 10 minutes.

[Example 10]
Pieces (50 × 50 mm) are cut out from the new electrodes 1 and 2 and heated in the atmosphere at 140 ° C. for 1 hour, then air-cooled, and thereafter, an aqueous hydrochloric acid solution having a concentration of 10 to 11% by mass at 40 to 42 ° C. It was immersed for 10 to 30 seconds (10 pieces each), and then washed with water. And about this piece after this water washing, the leakage current was measured by the method similar to the case of Example 2. FIG.

  The measurement results of this leakage current are shown in FIGS. As can be seen from FIGS. 10 to 11, in the case of immersion in a 10 mass% hydrochloric acid aqueous solution at 40 ° C., a difference in durability between the electrodes 1 and 2 could be detected by immersion for 30 seconds. In the case of immersion in an hydrochloric acid aqueous solution of 11% by mass at 40 ° C., a difference in durability between the electrode 1 and the electrode 2 was detected by immersion for 20 seconds, but the leakage current of the electrode 1 also varied due to corrosion after immersion for 30 seconds. The difference in durability between electrode 1 and electrode 2 could not be detected. In the case of immersion in an aqueous hydrochloric acid solution having a concentration of 10% by mass at 42 ° C., it was possible to detect a difference in durability between the electrodes 1 and 2 after immersion for 20 seconds. The difference in durability between electrode 1 and electrode 2 could not be detected. In the case of immersion in an aqueous 11 mass% hydrochloric acid solution at 42 ° C., a difference in durability between the electrode 1 and the electrode 2 could be detected by immersion for 10 seconds, but the leakage current of the electrode 1 also varied due to corrosion after immersion for 30 seconds. The difference in durability between electrode 1 and electrode 2 could not be detected.

  If the immersion time is less than 30 seconds, the evaluation test work must be performed quickly, and the measurement accuracy may decrease due to the large influence of the difference in hydrochloric acid immersion time. Therefore, it is desirable to use an aqueous hydrochloric acid solution having a concentration of 40% or less and 10% by mass that can be evaluated by immersion for 30 seconds or more.

  The durability evaluation method for an aluminum alloy electrode according to the present invention is a method of causing variation in etching characteristics (etching shape and etching rate) within the surface of a processed substrate for an anodized aluminum alloy electrode used in a dry etching apparatus. The difficulty (whether or not it is easy to cause variation) is useful because it can be predicted without actually using the aluminum alloy electrode.

It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 2, (1) of FIG. 1 shows the result about the electrode 1, and (2) of FIG. . It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 concerning Example 3, (1) of FIG. 2 shows the result about the electrode 1, and (2) of FIG. . It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 4, (1-1), (1-2), (1-3), (1-4) of FIG. (2-1), (2-2), (2-3) and (2-4) in FIG. 3 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 5, (1-1), (1-2), (1-3) of FIG. 4 is the result about the electrode 1 (piece), (2-1), (2-2), and (2-3) in FIG. 4 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 concerning Example 7, (1-1), (1-2), (1-3) of FIG. 5 is the result about the electrode 1 (piece), (2-1), (2-2), and (2-3) in FIG. 5 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 concerning Example 7, (1-4), (1-5), (1-6) of FIG. 6 is the result about the electrode 1 (piece), (2-4), (2-5) and (2-6) in FIG. 6 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 8, (1-1), (1-2), (1-3) of FIG. 7 is the result about the electrode 1 (piece), (2-1), (2-2), and (2-3) in FIG. 7 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 9, (1-1), (1-2), (1-3) of FIG. 8 is the result about the electrode 1 (piece), (2-1), (2-2), and (2-3) in FIG. 8 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 9, (1-4), (1-5), (1-6), (1-7) of FIG. (2-4), (2-5), (2-6) and (2-7) in FIG. 9 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 10, (1-1), (1-2), (1-3) of FIG. 10 is the result about the electrode 1 (piece), (2-1), (2-2), and (2-3) in FIG. 10 show the results for the electrode 2 (piece). It is a figure which shows the measurement result of the leakage current of the electrodes 1-2 which concern on Example 10, (1-4), (1-5), (1-6), (1-7) of FIG. (2-4), (2-5), (2-6) and (2-7) in FIG. 11 show the results for the electrode 2 (piece). FIG. 12A is a drawing-substituting photograph showing micrographs of the surfaces of piece A-1 (electrode 1) and piece A-2 (electrode 2) according to Example 6, and FIG. FIG. 12B is for the electrode 2. It is a figure which shows the example of the measuring method of the leakage current of the aluminum alloy electrode surface.

Claims (5)

  A method for evaluating the durability of an anodized aluminum alloy electrode used in a dry etching apparatus, wherein the electrode is held at a temperature of 120 to 200 ° C. for 1 hour or more, then immersed in an aqueous hydrochloric acid solution, A method for evaluating the durability of an aluminum alloy electrode, characterized by measuring variations in leakage current distribution on the electrode surface.   The method for evaluating the durability of an aluminum alloy electrode according to claim 1, wherein the temperature of the aqueous hydrochloric acid solution is 10 ° C or higher.   The method for evaluating the durability of an aluminum alloy electrode according to claim 1 or 2, wherein the temperature of the hydrochloric acid aqueous solution is 40 ° C or lower.   The method for evaluating the durability of an aluminum alloy electrode according to any one of claims 1 to 3, wherein the concentration of the hydrochloric acid aqueous solution is 0.1 mass% or more.   The method for evaluating the durability of an aluminum alloy electrode according to any one of claims 1 to 4, wherein the concentration of the hydrochloric acid aqueous solution is 10% by mass or less.

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