JP2001261372A - Method of etching glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for micro-channeling processing in an anisotropic state on a glass substrate by a wet etching method. SOLUTION: A chromium thin film layer and a resist thin film layer are formed on a glass substrate, and the chromium thin film layer and the glass substrate are subjected to an etching treatment by using each an exclusive-use etching liquid to enable the channel pattern in the anisotropic state to be constructed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching method for finely processing glass, and more particularly to an anisotropic shape rather than an isotropic shape when compared with conventional wet etching of glass. Has a feature that makes it possible to obtain

[0002]

2. Description of the Related Art In a conventional glass etching method, a resist thin film layer is formed on a glass substrate, the resist is exposed to light, a fine pattern is drawn, and the glass is immersed in hydrofluoric acid which is corrosive to glass. Thus, the drawn pattern was actually transferred onto a glass substrate to form a microchannel.

[0003] This method makes it possible to construct a micro channel on a glass substrate. Currently, a micro total analysis system (Micro Total Analysis System) is used.
Analysis Systems), μTA for short
S, or Lab-on-a-Chip, is being studied around the world.

[0004] The background of these studies is that the amount of specimen sample is extremely small, the amount of reagent is extremely small, the amount of waste is greatly reduced, the measurement time is significantly reduced, the analysis resolution is enhanced, and the measurement equipment is extremely small. It is expected that miniaturization is expected.

[0005] For example, Oak Ridge Natio
J. nal Laboratory M. Ramsey
According to the group, a width of 24 μm (hereinafter abbreviated as μm) and an effective length of 200 μm were formed on a glass substrate.
m, separation of rhodamine B and dichlorofluorescein in a microchannel having a channel depth of 7 μm within only 1 ms (Analytical).
Chemistry 70, 3476-3480
1998).

[0006]

According to the above document, however, microchannels are formed on a glass substrate by a wet etching method. However, since the glass itself has no crystal orientation, isotropic etching is performed. A semicircular bowl-shaped channel as shown in FIG. 4 is formed.

In the case of separation analysis using a microchannel, in such a bowl-shaped microchannel, the focal position of irradiation light for detecting a specimen must be accurately maintained, and detection by scattering of output light is required. There was a problem that loss was difficult to avoid.

Another problem of the wet etching method is that the adhesiveness between the glass substrate and the resist thin film layer is poor, and the resist layer gradually peels off when the glass is etched for a long time, so that a desired microchannel cannot be obtained. Therefore, the depth of the channel can be formed only about 10 μm.

In order to solve these wet etching problems, a dry etching method for forming an anisotropic etching shape has also been developed (for example, JP-A-6-219781).
However, as in the case of silicon processing, a dedicated device is required, and it is very expensive, so that there is a problem that no one can use it easily as compared with the wet etching method.

[0010]

In order to solve the above-mentioned problems, the method for etching glass according to the present invention improves the adhesion between a resist thin film layer and a glass substrate, can be applied to etching for a long time, and can be used for deep micro etching. It is characterized in that the channel can be formed and the etching can be performed in an anisotropic trapezoidal shape instead of etching in a bowl shape.

According to the present invention, since the microchannel can be formed deeper than before, the handling of the sample and the reagent becomes easy, and the anisotropic etching pattern can be obtained, so that the sample and the reagent can stably stay. In addition, it is possible to provide a microchannel that facilitates focusing by light irradiation for specimen detection, suppresses scattered light, and can improve detection sensitivity.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The glass etching method according to claim 1 of the present invention is characterized in that the glass is etched by anisotropic etching, and the glass has no crystal orientation. It is possible to form an anisotropic channel shape similar to a silicon substrate on a substrate.

According to the glass etching method of the present invention, a chromium thin film layer is formed on a glass substrate before forming a resist thin film layer serving as a mask pattern for finely processing the glass substrate by wet etching. The glass etching method according to claim 1, wherein the glass is etched by forming a chromium thin film layer and a gold thin film layer on a glass substrate in advance. In this case, the resist layer is prevented from peeling off from the glass substrate, etching can be performed for a long time, and deep microchannels can be achieved.

Next, according to a third aspect of the present invention, there is provided a glass etching method according to the second aspect, wherein the chromium thin film layer on the glass substrate is formed with a resist thin film layer using a dedicated etching solution. 3. The method according to claim 1, wherein said etching has a role of protecting a glass side wall when etching the glass substrate.
In this method, the microchannel pattern transferred and drawn on the resist thin film layer is sequentially transferred to the chrome thin film layer, and finally, the drawing pattern of the resist thin film layer is accurately transferred to the glass substrate. At this time, a small amount of chromium migrates to the glass side wall and serves to protect the etching of the glass side wall, so that isotropic etching is prevented and an anisotropic etching shape is formed. It can be realized.

Next, in the method of etching glass according to claim 4 of the present invention, the method of etching a glass substrate is wet etching using hydrofluoric acid. This is a method for etching glass, and anisotropic etching can be achieved by using hydrofluoric acid, which has been widely used as an etchant for forming microchannels on a glass substrate.

Next, in the method of etching glass according to claim 5 of the present invention, the material of the glass used as the substrate is not particularly selected from glass materials such as borosilicate glass and quartz glass. 1, Claim 2, Claim 3
And the glass etching method according to claim 4, wherein anisotropic microchannels can be realized on the glass substrate without particular limitation on the material of the glass.

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.

In FIG. 1, 30 mm (hereinafter, referred to as 30 mm)
1 shows an example of a microchamber constructed on a borosilicate glass of 50 mm × 550 micrometers (hereinafter abbreviated as μm).

FIG. 1 is a cross-sectional view schematically showing the shape of a microchamber constructed by the glass etching method according to the present invention. A planar structure can be confirmed at the bottom of the microchamber.

The size of the upper part of the glass chamber is 175 μm.
m square, base 110 m square, chamber depth 3
It was 0 μm. This indicates that the glass substrate is anisotropically etched at an angle of about 50 degrees.

FIG. 2 is a schematic view showing the shape of a microchannel constructed from quartz glass as a substrate by the glass etching method according to the present invention from above.

As shown in the schematic diagram of FIG. 2, it can be observed that there is a clear contour between the upper portion and the base portion of the quartz glass substrate similarly to the result of FIG. The existence of this contour is due to the result of etching the quartz glass substrate in an anisotropic manner.

The width of the microchannel is 1 at the top of the substrate.
It was 65 μm, the base was 125 μm, and the depth of the channel was about 30 μm, indicating that etching was performed at an angle of about 40 degrees.

As described above, according to the present invention, microchannels can be formed anisotropically on a glass substrate by wet etching without selecting a glass material.

Next, the process of etching the glass substrate will be described with reference to FIG.

FIG. 3 shows process steps for constructing a microchannel on a glass substrate.

First, to remove organic substances on the surface of the glass substrate, the glass substrate is washed with 5% (hereinafter abbreviated as “%”) hydrofluoric acid for 15 seconds, washed with ultrapure water, and then washed with acetone in acetone.
Sonication for 5 minutes, washing with ultrapure water, then sonication for 5 minutes in methanol, and washing with ultrapure water (A).

Next, in order to deposit a chromium thin film layer on the glass substrate, chromium is vapor-deposited on the glass substrate from which organic substances on the surface have been removed by a sputtering apparatus in which the inside of the chamber is set at 100 degrees for 10 minutes. The thickness of the chromium thin film layer deposited at this time is 2
00 nanometers (nm) (B).

Next, in order to form a resist thin film layer on a glass substrate on which a chromium thin film layer has been deposited, a resist solution (HPR1183 positive resist made by Fuji Film Ohlin Co., Ltd.) is applied to the entire surface of the substrate, and a uniform thickness is applied by a spin coater. The layer was baked to cure the resist thin film layer. The thickness of the resist thin film formed at this time is 2 μm.
(C).

Next, in order to draw a microchannel pattern on the glass substrate on which the resist thin film layer was formed, ultraviolet exposure and development processing were performed (D), and the channel pattern was transferred and drawn on the resist thin film layer (E).

Next, in order to etch the chromium thin film layer, the substrate was immersed in a chromium etching solution (manufactured by Kanto Kagaku) until the glass substrate was exposed (F).

Next, 5% for etching the glass substrate
The substrate was immersed in a hydrofluoric acid solution for 25 hours (G).

Finally, the resist thin film layer used as a mask was washed with acetone to remove it, and the chromium thin film layer was washed with a mixed solution of potassium ferricyanide and sodium hydroxide (H).

By following the above procedure, it becomes possible to construct a microchamber or microchannel for forming an anisotropic etching pattern shown in FIGS. 1 and 2 on a glass substrate. The groove depth of the microchannel to be constructed can be changed by changing the immersion time in hydrofluoric acid.

As described in the above embodiment, the glass etching method of the present invention can be applied without any particular limitation on the material of the glass substrate.

[0036]

As described above, according to the glass etching method of the present invention, the glass substrate is provided with anisotropic microchannels by the wet etching method by depositing the chromium thin film layer on the glass substrate surface. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing the shape of a microchamber constructed in borosilicate glass according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a shape of a microchannel constructed in quartz glass according to the first embodiment of the present invention from above;

FIG. 3 is a process diagram of a microchannel construction of a glass substrate according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing an etching shape of a glass substrate according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Chromium thin film layer 3 Resist thin film layer 4 Mask pattern

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroaki Misawa 232-1 Otsubo, Hachiman-cho, Tokushima City, Tokushima Prefecture 1-31 Otsubo Residence F-term (reference) 4G059 AA01 AB06 AB07 AB11 AC01 BB04 5F043 AA18 BB22 BB27 DD22 FF03 GG10

Claims (5)

[Claims] 1. A method for etching glass, wherein the etching shape of the glass is anisotropic etching. 2. The method according to claim 1, wherein a chromium thin film layer is coated on the glass substrate by vapor deposition before forming a resist thin film layer serving as a mask pattern for finely processing the glass substrate by wet etching. Glass etching method. 3. The method according to claim 2, wherein the chromium thin film layer on the glass substrate is etched by a dedicated etching solution in accordance with a mask pattern formed by the resist thin film layer, thereby protecting the glass side wall when etching the glass substrate. The method for etching glass according to claim 1, wherein the method has a role. 4. The glass etching method according to claim 1, wherein the glass substrate is etched by hydrofluoric acid. 5. The glass according to claim 1, wherein the material of the glass used as the substrate is not particularly selected from glass materials such as borosilicate glass and quartz glass. Etching method.