JP2001271181A - METHOD FOR ETCHING Cr FILM - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, in the case a Cr film is etched by using a Ce-containing etching solution, the etching solution is removed from the sun face of the substrate after the etching by an air knife and pure water washing, however, when pure water is used, Ce hydroxide deposits on the sun face so that immersing the etched plate into an acid solution is necessary for its removal, which results in the increase of treating tanks and the number of operation steps. SOLUTION: In a water washing tank, 32 is CO2 35 is previously, blowed and the value of pH of the pure water 32 is controlled to an acidic region and the pure water is chilled by a refrigerator 36. By this previous adjustment, at the time of washing a glass substrate 1 with a Ce-containing etching solution after etching a Cr film 2 on the substrate, the deposition of Ce hydroxide on the surface of the substrate 1 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for etching a Cr film, and more particularly to an etching method using an etching solution containing Ce.

[0002]

2. Description of the Related Art A method of etching a Cr film with an etching solution containing Ce is disclosed in Japanese Patent Application Laid-Open No. 62-1285.
There are methods disclosed in Japanese Patent Application Laid-Open No. 29-158 and Japanese Patent Application Laid-Open No. 58-1178662.

[0003] JP-A-62-128529 discloses C
After the etching of the r film is completed, the entrance shower is washed with water,
The present invention relates to upper and lower shower nozzle water washing and automatic washing using an air knife or the like.

When an etching solution containing Ce is used for etching a Cr film, Ce as an etching material adheres to the washing nozzle. The adhered matter is ejected to the substrate with the resist pattern during the processing, and the resist pattern is scraped off and the Cr is etched.

[0005] To prevent this, after the etching of the Cr film is completed, the Cr film is switched from an etching solution containing Ce to an acidic solution.

[0006]

In the above-described methods for etching a Cr film, any of the above-described methods for etching a Ce film by etching a Cr film.
This is a process based on the premise of precipitation, and has the problem of increasing the number of processing tanks and the number of steps.

An object of the present invention is to provide a method for etching a Cr film, which prevents the deposition of Ce itself after etching the Cr film using an etching solution containing Ce.

[0008]

According to a first method of etching a Cr film of the present invention, a Cr film is deposited on a substrate, and the Cr film is etched with an etching solution containing Ce (cerium). The Cr film is patterned into a predetermined pattern, and thereafter, an inert gas is blown onto the substrate to remove most of the etching solution from the substrate, and subsequently, the etching solution remaining on the substrate is washed with pure water. A method of etching a Cr film to be removed from the substrate, wherein the step of removing the etching solution remaining on the substrate from the substrate by pure water washing is performed by low-pH pure water washing with a pH value set to 5.0 or less. it features a comprising the low pH of pure water rinsing is carried out by pH value subjected to bubbling treatment of carbon dioxide (CO ₂₎ in pure water above 6.5, the pH of pure water washing with water, Ekion is 10 to 1
It is carried out at 5 ° C.

Next, in a second method for etching a Cr film according to the present invention, a Cr film is deposited on a substrate, and the Cr film is
The Cr film is patterned into a predetermined pattern by etching with an etchant containing e (cerium), and then an inert gas is blown on the substrate to remove most of the etchant from the substrate, A method of etching a Cr film in which the remaining etchant is removed from the substrate by washing with pure water, wherein the inert gas is blown onto the substrate to remove most of the etchant from the substrate; Between the step of removing the etching solution remaining in the substrate by washing with pure water, characterized by having a step of immersing the substrate in an acid solution, wherein the acid solution is nitric acid, hydrochloric acid, perchloric acid A mixed solution containing the etching solution remaining on the substrate from the step of immersing the substrate in an acidic solution. During moving to step of removing, the ratio of the acid solution and the pure water to the total of the acidic solution and the pure water is changed linearly with respect to the immersion time,
That is.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing embodiments of the present invention, the features of the present invention will be briefly described.

The present invention is characterized by a processing method for performing a water-washing process after etching a material to be etched containing a Cr film using an etching solution containing Ce (cerium).

Specifically, after the etching of the material to be etched is completed, the etching solution remains on the substrate even if air is blown. However, when the substrate is subsequently washed with water, carbon dioxide (CO ₂ ) is previously removed. Adjust the pH by bubbling,
Further, pure water kept at a low temperature is prepared, and pure water cleaning is performed through pure water under the conditions.

Next, a first embodiment of the present invention will be described.
This will be described with reference to FIGS.

In this embodiment, the material to be etched is Cr
Of the substrate with an etching solution containing Ce, and a washing tank for washing the Ce attached to the substrate with water after the etching process. The outline of the etching process of the Cr film is as follows.

First, a Cr film 2 as a material to be etched is formed on a glass substrate 1 by magnetron sputtering, a resist film is applied, and the resist film is exposed and developed to form a resist pattern 3.

Next, the Cr film 2 on the glass substrate 1 is
Is selectively etched using the resist pattern 3 as a mask by an etching apparatus 100 using an etching solution containing Thereafter, the resist pattern 3 is peeled off, and the patterning of the Cr film 2 is completed.

Next, the details of the etching process of the Cr film of the present embodiment will be described with reference to FIGS. FIG.
FIG. 2 is a schematic view of the etching apparatus of the present embodiment, and FIG.
FIG. 3 is an explanatory view of an etching process for each of the main steps constituting the etching apparatus.

First, the glass substrate 1 provided with the resist pattern 3 is placed on a transport roller 10 and transported to an etching bath 20.

At this time, an etching solution 22 is drained over the entire surface of the glass substrate 1 with the resist pattern 3 at the entrance shower 21 of the etching bath 20.

Next, the glass substrate 1 with the resist pattern 3
Is transported to the etching tank 20, the etching tank 20
The etchant 22 is showered on the entire surface of the glass substrate 1 from the upper and lower showers 23 inside, and the Cr film 2 is etched (FIG. 2A).

The entrance shower 21 is provided on the entire surface of the glass substrate 1 before the upper and lower showers in order to eliminate non-uniformity of etching generated when the etching liquid 22 is showered on the glass substrate 1 from the upper and lower showers 23. The end of the etching is usually identified using a light transmission sensor or the like (not shown). If the etching speed of the Cr film 2 which is the film to be etched is known, processing may be performed for a fixed time (FIG. 2B).

When the etching of the Cr film 2 is completed, the glass substrate 1 with the resist pattern 3 is transported to the next tank. In general, it is necessary to prevent the etching solution 22 from being carried into the next tank. For the purpose, while the glass substrate 1 is being conveyed in the etching apparatus 100, N ₂ or the like is blown from a unit called an air knife 24 over the entire surface of the glass substrate 1 to remove the etching solution 22 from the surface of the glass substrate 1. It is brought into the next washing tank 30.

The glass substrate 1 is placed in the etching tank 20 described above.
Similarly to the above, in the washing tank 30, pure water 32 enters the entire surface of the glass substrate 1 and is poured from the entrance shower 31.

Next, the pure water 32 is showered from the nozzles of the upper and lower showers 33 for a predetermined time to completely remove the etching solution 22 partially remaining on the surface of the glass substrate 1.

When the rinsing process is completed, the glass substrate 1 is conveyed. At this time, similarly to the etching bath 20, after the rinsing shower is completed, N ₂ is blown with an air knife 34 to pour pure water 32 from the surface of the glass substrate 1. After complete removal, the glass substrate 1 is carried out of the etching apparatus 100 (FIG. 2C).

In this embodiment, the etching of the Cr film 2 is completed and the glass substrate 1 with the resist pattern 3 is placed in the washing tank 30.
Is transported, and is characterized by a processing method when the glass substrate 1 is washed with water in the washing tank 30.

Conventionally, the pure water to be washed in the washing tank has a pH value of about 6.5 to 7.0 and room temperature, but in the present embodiment, the CO ₂ gas 35 is introduced into the pure water 32 to purify the pure water. Water 32p
The H value is controlled to 5.0 or less, and the temperature of the pure water 32 is set to 1
It is characterized in that the glass substrate 1 is treated at a low temperature of about 0 to 15 ° C.

The pH value of CO ₂ is controlled by mixing it into pure water using a commercially available bubbling apparatus. Further, the temperature of pure water can be controlled by controlling the temperature of the pure water at a low temperature using the refrigerator 36.

The washing process with pure water was introduced CO ₂ gas in this embodiment, it is sufficient to practice about a minimum of about 10 seconds, the processing time than this, washing with water flow of washing many becomes the CO ₂ Bubbling is not in time, p during processing
There is no problem even if the H value increases.

The etching solution containing Ce is very acidic and strongly oxidizing, because Ce itself is very acidic and strongly oxidizing.

For this reason, especially when mixed with an alkaline chemical having a high pH value, Ce itself precipitates on the glass substrate as Ce hydroxide. This is more pronounced at higher temperatures. The precipitated Ce hydroxide cannot be removed unless it is immersed again in a strongly acidic chemical (eg, hydrochloric acid / nitric acid / perchloric acid).

The deposited Ce not only lowers the transmittance of the glass substrate but also diffuses into the gate insulating film when forming a thin film transistor, deteriorating the transistor characteristics and causing display unevenness. In the present embodiment, it is possible to prevent the precipitation of Ce hydroxide by mixing CO ₂ into pure water, bringing the pH value of pure water to an acidic region, and lowering the temperature of pure water. it can.

Next, a second embodiment of the present invention will be described.
This will be described with reference to FIG.

FIG. 3A is a schematic diagram showing a washing tank to which the present embodiment focuses, and FIG. 3B shows how the processing liquid of the glass substrate according to the present embodiment changes with processing time. It is a graph.

In the first embodiment, the pure water is bubbled with CO ₂ to prevent the precipitation of Ce hydroxide itself. However, in the second embodiment, Ce hydroxide is deposited without increasing the number of treatment tanks. And a method for removing the same.

The process up to the etching of the Cr film is exactly the same as that of the first embodiment. However, after the etching of the Cr film is completed, the glass substrate is moved from the etching bath to the washing bath 40 and the nitric acid / nitride is supplied to the entrance shower 41. After the shower treatment using the acidic liquid 42 composed of hydrochloric acid / perchloric acid or the like, the upper and lower showers 43 using ordinary pure water 47 may be performed in the same washing tank 40.

At this time, the change in the composition ratio of the processing solution with respect to the processing time from the time when the glass substrate enters the entrance shower 41 of the washing tank 40 to the time when the entire glass substrate completely falls under the upper and lower showers 43 of pure water. FIG. 3B is a graph showing the state focusing on one place of the glass substrate surface.

In the above embodiment, when the glass substrate enters the washing tank in the washing tank, the glass substrate is exposed to the entrance shower of the acidic liquid at the entrance, and then switched to the pure water upper and lower showers. Ce hydroxide remaining on the surface of the glass substrate can be removed.

[0039]

As described above, according to the Cr film etching method of the present invention, pure water is previously added to pure water in the washing tank.
₂ to bring the pH value of pure water to the acidic range,
In addition, by lowering the temperature of pure water, it is possible to prevent precipitation of Ce hydroxide on the surface of the glass substrate when the glass substrate etched with the etching solution containing Ce is washed with water.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an etching apparatus for performing a method for etching a Cr film according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a state of processing in each processing tank constituting the etching apparatus of FIG.

FIG. 3 is a schematic view showing a washing tank for performing a method for etching a Cr film according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Cr film 3 Resist pattern 10 Conveyance roller 20 Etching tank 21, 31, 41 Entrance shower 22 Etching liquid 23, 33, 43 Upper and lower shower 24, 34, 44 Air knife 30, 40 Rinse tank 32, 47 Pure water 35 CO ₂ gas 36 Refrigerator 42 Acid solution 100 Etching device

Claims (7)

[Claims] A Cr film is deposited on a substrate,
The film is etched with an etching solution containing Ce (cerium) to pattern the Cr film into a predetermined pattern, and then an inert gas is blown onto the substrate to remove most of the etching solution from the substrate, Subsequently, a Cr film etching method for removing the etching solution remaining on the substrate from the substrate by washing with pure water, wherein the step of removing the etching solution remaining on the substrate from the substrate by washing with pure water is performed at pH Set the value to 5.
A method for etching a Cr film, comprising washing with low pH pure water set to 0 or less. 2. The low-pH pure water washing has a pH value of 6.5.
_{2. The} method for etching a Cr film according to claim 1, wherein said method is performed by subjecting said pure water to a bubbling treatment of carbon dioxide (CO ₂ ). 3. The low-pH pure water washing has a sound of 10 to 1
3. The method for etching a Cr film according to claim 2, wherein the method is performed while maintaining the temperature at 5 ° C. 4. The method according to claim 1, wherein the low-pH pure water washing is at least 10
4. The method for etching a Cr film according to claim 3, wherein the etching is performed for seconds. 5. The method according to claim 5, wherein a Cr film is deposited on the substrate,
The film is etched with an etching solution containing Ce (cerium) to pattern the Cr film into a predetermined pattern, and thereafter, an inert gas is blown onto the substrate to remove most of the etching solution from the substrate. A method for etching a Cr film in which the etchant remaining on a substrate is removed from the substrate by washing with pure water, wherein the inert gas is blown onto the substrate to remove most of the etchant from the substrate, A step of immersing the substrate in an acidic solution between the step of removing the etching solution remaining on the substrate from the substrate by pure water washing. 6. The method for etching a Cr film according to claim 5, wherein the acidic liquid is a mixed liquid containing nitric acid, hydrochloric acid, and perchloric acid. 7. During a period from a step of immersing the substrate in an acidic solution to a step of removing the etchant remaining on the substrate from the substrate by washing with pure water, the amount of the acidic solution and the pure water with respect to the total of the acidic solution and the pure water is changed. 7. The method for etching a Cr film according to claim 6, wherein the ratio of the acidic liquid and the pure water changes linearly with the immersion time.