JP2881714B2 - Moisture sensitive element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitive humidity sensor using an organic polymer resin material as a moisture sensitive film, and more particularly to an upper electrode formed on a moisture sensitive film and an upper electrode formed on a substrate. The present invention relates to a connection structure with an electrode connection terminal.

[0002]

2. Description of the Related Art FIG. 3 is a plan view for explaining the structure of a conventional moisture-sensitive element of this type. 3A, first, as shown in FIG. 3A, a thin-film lower electrode 2, a lower electrode connection terminal 2a, and an upper electrode connection terminal 4a are formed on the surface of the insulating substrate 1, and then, as shown in FIG. As shown in b), the moisture-sensitive film 3 is formed on the entire area of the insulating substrate 1 except for the connection terminal. Next, as shown in FIG. 3C, after the upper electrode 4 and the extension piece 4b of the upper electrode 4 are formed on the moisture-sensitive film 3 over the upper electrode connection terminal 4a, as shown in FIG. As shown in FIG.
a step portion of the moisture sensitive film 3 between the noble metal film 5 and the extension piece 4b.
After making electrical connection, a lead wire 6 is connected to the connection terminal 4a for the upper electrode and the connection terminal 2a for the lower electrode, and the upper electrode 4 and the lower electrode 2 with respect to the relative humidity of the moisture sensitive film 3 are connected. A change in the capacitance value or impedance between them was detected as a change in humidity. This type of moisture-sensitive element has been proposed in, for example, Japanese Patent Application Laid-Open No. 60-239657.

[0003]

However, the moisture-sensing element thus constructed has a high adhesion between the extended piece 4b of the upper electrode 4 and the noble metal film 5 or the noble metal film 5 and the upper electrode connection terminal 4a. However, there is a problem that peeling is liable to occur and reliability is lowered. In other words, since the metal film overlaps and covers the step portion of the moisture sensitive film 3,
There is a problem that it is difficult to provide mechanical strength as a wiring portion. This is because, in FIG. 3, the upper electrode 4 and the extension piece 4b are formed of, for example, a thin moisture permeable film of gold, and the noble metal film 5 is made of thick gold or platinum. Most of the area of the connection portion has mechanical strength due to the adhesion between the gold and the moisture-sensitive film 3 and is easily peeled off.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to improve the connectivity between an upper electrode and a connection terminal for an upper electrode.
An object of the present invention is to provide a moisture-sensitive element having improved quality and reliability.

[0005]

In order to achieve the above object, the present invention provides a connection terminal for an upper electrode on a substrate and covers a step portion of the moisture-sensitive film from the connection terminal for the upper electrode. formed to the layer of the metal film humidity-sensitive membrane, upper electrode metal film and the upper electrode and the metal film on the humidity sensitive film
The contact was made in a state of being arranged below the pole .

[0006]

As the metal film in the present invention, a material having good adhesion to the moisture-sensitive film, the connection terminal of the upper electrode and the substrate can be selected.
In addition, since the metal film is located under the upper electrode, the adhesion is high.
That is, the connectivity between the upper electrode and the connection terminal for the upper electrode is improved.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a process for explaining a configuration according to one embodiment of a moisture-sensitive element according to the present invention using a manufacturing method thereof. In FIG. 1, first, as shown in FIG. 1A, for example, Pt is formed on an electrode forming surface of a substrate 11 having a thickness of about 0.5 mm made of an insulator such as non-alkali glass or quartz or a semiconductor such as silicon. , Au, Nb / Pt,
A metal layer composed of at least one layer such as Cr / Pt or Ti / Pt is deposited by a vapor deposition or sputtering method.
Å is applied to a thickness of about 1 μm, patterned, and the lower electrode 12, a connection terminal 12 a for the electrode (not shown)
And the connection terminal 14a for upper electrodes is formed.

Next, PMMA and cross-linked PMM are formed over the entire area of the substrate 11 on which the lower electrode 12, the electrode connection terminals 12a and the upper electrode connection terminals 14a are formed.
A, a polymer resin material such as polyimide, polysulfone, or polyethersulfone is applied by spin coating or dipping, heated, and dried to form a moisture-sensitive film 13 having a thickness of about 1 to 10 μm.

Next, the moisture-sensitive film 13 thus formed is formed.
As shown in FIG. 1 (b), the moisture-sensitive film 13 in the electrode connection terminal forming region on the substrate 11 is removed by, for example, a dry etching method, and the lower electrode connection terminals 12a (not shown) and the upper portion are formed. The electrode connection terminals 14a are exposed.
As a result, the etched end 13a of the moisture-sensitive film 13 is formed with a smooth surface curvature.

Next, as shown in FIG. 1C, Cr, Nb, Mo, and Cr extend from the upper surface of the end portion of the moisture-sensitive film 13 to the main surface of the connection terminal 14a for the upper electrode via the etching end portion 13a.
A metal layer having high adhesion to the material of the moisture sensitive film 13 such as Ta, Ti, TiW, NiCr, Pd or Pt is deposited by a vapor deposition or sputtering method to a thickness of about 500 to 1 μm, and is patterned to form a metal. A film 15 is formed.

Next, as shown in FIG. 1D, Au.sub.2 is applied on the moisture-sensitive film 13 including the metal film 15 formed on one end of the moisture-sensitive film 13. A metal having high corrosion resistance and high moisture permeability, such as Cr, Pt or Pd, is deposited by evaporation or sputtering.
An upper electrode 14 is formed by applying a thickness of about 1000 and patterning. Thereby, as shown in the plan view of FIG. 2, one end of the metal film 15 is formed on the main surface of the connection terminal 14 a for the upper electrode, and the other end of the metal film 15 formed on one end of the moisture-sensitive film 13. Upper electrode 14 on side surface
Are formed in contact with each other, that is, the metal film 15 is
A structure is obtained in which the electrodes 14 are placed under the electrodes 14 and are in contact with each other. FIG. 1D shows a cross section taken along line AA 'in FIG.

In such a configuration, the metal film 15
Since the adhesiveness with the moisture-sensitive film 13 is good, the adhesive strength of the upper electrode 14 near the moisture-sensitive film etched end 13a is improved, and the strength is improved . Also, the metal film 15 is placed under the upper electrode 14.
Because the contact is made in the arranged state, the adhesion of the metal film 15
The force increases, making it difficult to peel off.

[0013]

As described above, according to the present invention,
Formed from the upper electrode connecting terminal provided with a connection terminal of the upper electrode on the substrate to humidity sensitive film of the step portion humidity sensitive film to further metal film in the form of coating and a top electrode on the moisture sensitive film Metal film and metal film are arranged under the upper electrode
Close contact between metal film and moisture-sensitive film
As a result , the connectivity between the upper electrode and the connection terminal for the upper electrode is improved, and the moisture-sensitive element having high quality and reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a manufacturing process illustrating a configuration of an example of a moisture-sensitive element according to the present invention.

FIG. 2 is a plan view of the moisture-sensitive element according to the present invention formed by the manufacturing process of FIG. 1;

FIG. 3 is a plan view of a manufacturing process illustrating a configuration of a conventional moisture-sensitive element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate 12 Lower electrode 12a Connection terminal for lower electrodes 13 Moisture sensitive film 13a Etched edge 14 Upper electrode 14a Connection terminal for upper electrode 15 Metal film

Claims (2)

(57) [Claims] 1. A moisture-sensitive element in which a lower electrode, a moisture-sensitive film made of an organic polymer resin material, and a moisture-permeable upper electrode are sequentially laminated on a substrate, wherein a connection terminal for the upper electrode is provided on the substrate. the upper electrode layer of the metal film in the form of covering the step portion of the moisture sensitive film from the connection terminal is formed to over the moisture sensitive film, the gold and the upper electrode and the metal film on the moisture sensitive film
A moisture-sensitive element, wherein the element is in contact with a metal film disposed below the upper electrode . 2. The moisture-sensitive element according to claim 1, wherein the upper electrode connection terminal is formed below the metal film and has a larger area than the metal film.