JP2001259548A - Method for treating surface of glass substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the adhesion of the electrode layer formed on the surface of a glass substrate as a membrane at the time of manufacture of a solar cell. SOLUTION: In the method for treating the surface of the glass substrate, the surface of the glass substrate having the electrode layer formed thereon as a thin film is ultrasonically cleaned before washed with an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating a surface of a glass substrate on which an electrode layer is formed as a thin film.

[0002]

2. Description of the Related Art Generally, when manufacturing a solar cell,
As a pretreatment for forming a thin electrode layer as a lower electrode on the surface of the glass substrate, it is necessary to clean the surface of the glass substrate to remove particles.

[0003] Conventionally, however, it is considered that the acid dissolves the glass and is not suitable for cleaning the glass substrate. Therefore, the surface of the glass substrate is cleaned with an organic solvent.

[0004]

The problem to be solved is that if an electrode layer is formed as a thin film on the surface of a glass substrate washed with an organic solvent, the adhesion of the electrode layer is weak,
This means that the electrode layer peels off from the glass substrate during use of the solar cell.

[0005]

In the surface treatment method for a glass substrate according to the present invention, basically, the surface of the glass substrate is made fine and the adhesion of the electrode layer formed on the glass substrate is reduced. To improve the surface, the surface of the glass substrate is etched with an acid.

In this case, in particular, in the present invention, if the surface of the glass substrate is etched with an acid while the surface is contaminated with dirt and impurities, relatively large debris adhering to the surface is removed. The surface of the glass substrate is ultrasonically cleaned as a pretreatment, and then the cleaning is performed so as to prevent the adhesiveness of the electrode layer which remains as it is without being removed by etching and is formed thereon as a thin film from being reduced. The etched surface is etched with an acid.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a processing step before a thin film of an electrode layer as a lower electrode is formed on the surface of a glass substrate when the method for processing a surface of a glass substrate according to the present invention is adopted.

Here, first, as a first step, the surface of the glass substrate is ultrasonically cleaned with pure water. The ultrasonic cleaning is performed by ultrasonic waves in a frequency range of about 20 to 850 KHz.

Next, as a second step, the glass substrate is immersed in hydrogen fluoride to make the surface finer by an etching effect.

Next, as a third step, the hydrogen fluoride is washed away with running water.

Finally, as a fourth step, IPA
(Isopropyl alcohol) Dry the glass substrate with a dryer.

Thus, contamination (surface contamination) such as dust and impurities attached to the surface of the glass substrate is effectively removed by ultrasonic cleaning. Then, by immersing the ultrasonically cleaned glass substrate in hydrogen fluoride, particles on the glass surface are removed, and the surface of the glass substrate is finely divided in microns by an etching effect.

Therefore, the fine surface of the glass substrate increases the surface area, substantially increases the contact area with the electrode layer formed on the glass substrate, and improves the adhesion between the two.

Now, for example, as shown in FIG.
When an electrode layer 2 of molybdenum Mo is formed to a thickness of 0.5 μm on a glass substrate 1 made of soda-lime glass SLG having a thickness of 0.5 μm, etching conditions for the surface of the glass substrate 1 using hydrogen fluoride and Table 1 below shows the surface state of the electrode layer 2 formed on the etched surface of the glass substrate 1.

[0015]

Therefore, from the above results, it is effective to perform etching for 10 minutes or less using hydrogen fluoride having a concentration of 5% or less when actually manufacturing a solar cell.

Now, the electrode layer is formed as a thin film on the surface of a glass substrate etched with hydrogen fluoride under the same conditions, and the same electrode layer is formed on the surface of a glass substrate washed with an organic solvent as in the prior art. The peeling load of the electrode layer was measured by performing a scratch test with the thin film formed as described above, and the result was 553 g for the sample etched with hydrogen fluoride and 271 g for the sample washed with the organic solvent. Met.

FIG. 3 shows the measurement results of a scratch test of a sample etched with hydrogen fluoride water at that time. FIG. 4 shows a measurement result of a scratch test of the sample washed with the organic solvent at that time.

According to the measurement result of the scratch test, it is found that the sample etched with hydrogen fluoride has about twice the adhesion strength as the sample washed with the organic solvent.

Further, an electrode layer was formed under the same conditions on the surface of a glass substrate which was ultrasonically cleaned with pure water and then etched with hydrogen fluoride, and the surface of a glass substrate which was only etched with hydrogen fluoride. As a result of performing a scratch test at that time, the peeling load of the electrode layer in both samples was measured. As a result, 410 g of the sample not subjected to ultrasonic cleaning was 543 g of the sample subjected to ultrasonic cleaning.

FIG. 5 shows a measurement result of a scratch test of a sample which was subjected to ultrasonic cleaning with pure water and then etched with hydrogen fluoride water at that time. FIG. 6 shows a measurement result of a scratch test of a sample which was just etched with hydrogen fluoride water at that time.

According to the measurement results of the scratch test, the ultrasonic cleaning before etching the surface of the glass substrate with an acid dramatically improves the adhesion to the electrode layer formed on the surface of the glass substrate. It turns out that it improves.

[0023]

As described above, in the method for treating the surface of a glass substrate according to the present invention, the surface of the glass substrate on which the electrode layer is formed as a thin film is ultrasonically cleaned and then etched with an acid. It is possible to effectively remove contaminants such as dust and impurities attached to the surface of the glass substrate and particles on the glass surface, which are factors that reduce the adhesion of the electrode layer formed as a thin film on the surface of the glass substrate. . The surface of the glass substrate is fine due to the etching effect and the surface area is increased, and the contact area with the electrode layer formed on the glass substrate is substantially increased, thereby improving the adhesion between the two. ing.

[Brief description of the drawings]

FIG. 1 is a view showing a procedure of a processing step when a method for treating a surface of a glass substrate according to the present invention is specifically carried out.

FIG. 2 is a diagram showing a sample in which an electrode layer is formed on a glass substrate.

FIG. 3 is a characteristic diagram showing a measurement result of a scratch test of a sample in which an electrode layer is formed as a thin film on a surface of a glass substrate etched with hydrogen fluoride water.

FIG. 4 is a characteristic diagram showing a measurement result of a scratch test of a sample in which an electrode layer is formed as a thin film on a surface of a glass substrate washed with a conventional organic solvent.

FIG. 5 is a characteristic diagram showing measurement results of a scratch test of a sample in which an electrode layer is formed as a thin film on the surface of a glass substrate which has been subjected to ultrasonic cleaning with pure water and then etched with hydrogen fluoride water.

FIG. 6 is a characteristic diagram showing a measurement result of a scratch test of a sample in which an electrode layer is formed as a thin film on the surface of a glass substrate which is only etched with hydrogen fluoride water without ultrasonic cleaning with pure water.

[Explanation of symbols]

 1 glass substrate 2 electrode layer

Claims (2)

[Claims] 1. A method of treating a surface of a glass substrate, wherein the surface of the glass substrate on which an electrode layer is formed as a thin film is subjected to ultrasonic cleaning and then etched with an acid. 2. The surface treatment method for a glass substrate according to claim 1, wherein etching is performed for 10 minutes or less using a hydrogen fluoride solution having a concentration of 5% or less.