JPH0345177Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a microamperometry electrode formed on an insulating substrate.

(Prior Art and its Problems) Conventionally, electrochemical analysis is used as one of the means for measuring the concentration of ions and redox substances in a solution, and various electrochemical devices for this purpose are known. For example, in an electrochemical device for measuring hydrogen peroxide, when a platinum electrode is set at +0.6 V with respect to a saturated electrode using a potentiometer (e.g., potentiostat), hydrogen peroxide is oxidized on the electrode and It takes advantage of the fact that a current flows depending on the hydrogen oxide concentration (Shuichi Suzuki, ed., "Ion Electrodes and Enzyme Electrodes", p.80 Kodansha Scientific)
1981). In recent years, in the field of chemical analysis, particularly in the field of clinical chemistry analysis, with the increase in the number of analyzes and the number of analysis items, miniaturization of each analysis sample has been promoted, and there is a strong demand for miniaturization of the measurement electrode itself. However, conventional devices are composite electrodes that include a saturated liquid electrode that requires an internal solution and a liquid junction.
Miniaturization was difficult. On the other hand, devices have also been constructed that quantify hydrogen peroxide using only two electrodes without using a saturated electrode. This device uses platinum for the anode and silver-silver chloride for the cathode.
It is set to 0.65V (2nd "Fundamentals and Applications of Sensors" Symposium Proceedings P43). however,
This electrode has a three-dimensional shape with a platinum electrode surrounded by silver and silver chloride, so it can be miniaturized using silicon IC manufacturing processes (resist patterning, vacuum evaporation, sputtering, etc.). It is not suitable for mass production.

(Purpose of the invention) The purpose of the invention is to provide a microamperometry electrode that has a simple shape and is suitable for mass production.

(Structure of the device) At least two noble metal electrodes are formed on an insulating substrate from near one end of the substrate to near the other end, and the electrodes are formed in the center of the insulating substrate except for near both ends. A microamperometry electrode characterized by having a structure in which the electrode is covered with an insulating film.

(Description of Configuration) Next, the present invention will be described with reference to FIGS. 1 to 6.

FIG. 1 is a plan view showing an example of the present invention, in which a noble metal electrode is formed on one main surface of an insulating substrate having an elongated planar shape. Figures 2, 3 and 4
The figures are the dashed-dotted lines A-A', B-B', and
In the cross-sectional view along C-C', 1 is the noble metal electrode, 2 is the noble metal electrode,
3 indicates an insulating substrate, 3 indicates an insulating film, and 4 indicates a metal electrode from which a lead wire is drawn.

As the insulating substrate, for example, an insulating substrate such as a sapphire substrate or a semiconductor substrate such as a silicon substrate whose surface is covered with an insulating film can be used.
Gold and platinum are suitable as noble metals for electrodes. When platinum is used, a metal such as gold or aluminum is layered as the lead wire extraction electrode 4 in order to facilitate aluminum bonding or lead wire extraction using solder. For example, as an insulating film
Oxides such as Ta ₂ O ₅ and nitrides such as SI ₃ N ₄ can be used. The noble metal, oxide, and nitride can be formed by vapor deposition, sputtering, or the like. By changing the voltage settings,
Cations such as Zr ²⁺ , Cd ²⁺ , Pb ²⁺ , Cu ⁺² , C1 ^- ,
Anionic redox substances such as dichromate and permanganate such as ^1- can be measured. It can also be used as an electrode for measuring solution conductivity.

(Example) As an example of the present invention, an amperometric electrode having the shape shown in FIG. 1 was created. The size of the chip was 0.5 mm x 6 mm. Sapphire was used for the insulating substrate, and gold was used for the noble metal for the electrodes. Further, Ta ₂ O ₅ was formed as an insulating film.

Since a large amount of money was used, lead wire extraction electrodes were not formed.

FIG. 5 and FIG. 6 show an example in which hydrogen peroxide was measured using the electrode. FIG. 5 shows current changes due to potential scanning between the two electrodes when hydrogen peroxide is added and when hydrogen peroxide is not added. The current value around +1.1V changes significantly due to the addition of hydrogen peroxide. Therefore, we set the potential between the two electrodes to 1.1V, changed the hydrogen peroxide concentration, and measured the changes in the current value. As a result, as shown in Figure 6, there was a good straight line between the hydrogen peroxide concentration and the current value. A relationship was obtained.

Note that the shape of the noble metal electrode portion shown in FIG. 1 can also be easily changed according to the method of the present invention. 7th
An example of changing the shape of the electrode portion is shown in FIG. 7th
When electrodes having the shapes shown in Figs. 8 and 8 were used, the current-voltage characteristics were basically the same, but an increase in the current value was observed. The current value in the shape shown in FIG. 7 was 10% higher than in the shape shown in FIG. 1, and the current value in the shape shown in FIG. 8 was 20% higher than in the shape shown in FIG.

(Effects of the invention) Since the micro amperometric electrode of the invention has a structure in which a noble metal electrode is formed in a planar shape on one main surface of an insulating substrate, it is possible to use a semiconductor IC manufacturing process during manufacturing, and It is easy to obtain a chemically oxidized electrode. By miniaturizing the electrode, only a small amount of noble metal can be used, and therefore an inexpensive electrode can be obtained.

In addition, since the electrode of the present invention is formed on a flat insulating substrate, it is easy to obtain an electrode with a functional film such as a permselective film formed on the surface, and it is also possible to form a large number of electrodes on-chip. .

Furthermore, by manufacturing the microamperometry electrode of the present invention using a semiconductor IC manufacturing process, an electrode with uniform characteristics can be easily obtained.

[Brief explanation of the drawing]

Figure 1 is a plan view showing an example of the present invention; Figure 2 is a plan view showing an example of the present invention;
Figures 3 and 4 are A-A shown in Figure 1, respectively.
It is a sectional view taken along A', BB', and CC'. FIG. 5 is a voltamgram when the electrode of the present invention is used as a hydrogen peroxide electrode, and FIG. 6 is a diagram showing a calibration curve for hydrogen peroxide. FIG. 7 and FIG. 8 are diagrams showing an embodiment in which the shape of the electrode part is changed. In the figure, 1... noble metal electrode, 2... insulating substrate, 3... insulating film, 4... lead wire drawing metal electrode.

Claims (1)

[Scope of utility model registration request] At least two noble metal electrodes are formed in a planar shape on one main surface of the insulating substrate from near one end of the substrate to near the other end, and the electrodes are formed in a planar shape from near one end of the substrate to near the other end, and the electrodes are A microamperometry electrode characterized by having a structure in which the center portion is covered with an insulating film.