TW201435339A - Ion sensitive apparatus and method for fabricating the same - Google Patents

Abstract

An ion sensitive apparatus is disclosed in the present invention and at least comprises a substrate, a first electrode, a second electrode, a sensing film and a packaging material. The first electrode comprises a first body and a plurality of first fingers electronically connected with the first body. The second electrode comprises a second body and a plurality of second fingers electronically connected with the second body. Preferably, the first fingers and the second fingers are parallel and intersected with each other to overlap and form a sensing zone. The sensing film is disposed to cover the sensing zone and the packaging material is disposed on the surrounding of the sensing zone for packaging the sensing zone.

Description

Ion sensing device and manufacturing method thereof

The present invention relates to an ion sensing device, and more particularly to an ion sensing device for fabricating a polymer conductive film on a flexible substrate and measuring the resistance of the solution to be tested by using a finger electrode to measure the acid value of the solution to be tested. method.

With the advancement of medical care and the popularization of the concept of eugenics education, the world has gradually entered an aging society, and the proportion of the elderly population has increased significantly. In view of this, health care and care have become one of the most important issues in the 21st century. In particular, the establishment of the "Home Care" real-time monitoring system has the greatest development potential and market value. The so-called medical real-time monitoring is to accurately observe the subtle changes in the human body, so as to prevent the occurrence of diseases or the early treatment of diseases. There are many parts that can be observed for subtle changes, including the pH and composition of sweat, urine, and saliva. To achieve this goal, a sensing platform that accepts human body information into accurate electronic signals must be established. This platform can be called a Transducer.

At present, there are many researches on sensing components, among which the converter platform developed includes: ion selective electrode (ISE, Ion Selective Electrode), ion sensing field effect transistor (ISFET, Ion Sensitive field-effect transistor), optical addressing potential LAPS (Light Addressable Potentiometric Sensor), ion sensing organic field effect transistor (ISOFET, Ion Sensitive Organic) Field Effect Transistor) and sensing platforms such as GaN FETs. However, at present, these sensing platforms still have some parts to be improved, such as non-ideal effects such as time drift, hysteresis, temperature, etc., as well as packaging technology and reference electrode integration.

Of the many types of sensors, ion-sensing field-effect transistors (ISFETs) have received the most attention and attention. The structure of an ion-sensing field effect transistor (ISFET) is similar to that of a metal oxide semiconductor field effect transistor (MOSFET), and only a portion of the metal gate is replaced with a solution to be tested and a reference electrode. It was proposed by P. Bergveld in 1970. After decades of research and improvement by advanced people, it has the advantages of small size, fast response, long life and matching with advanced processes.

The sensing mechanism of the ion-sensing field-effect transistor is mainly that in different solutions to be tested, there are a number of different acid, alkali or neutral ions and the surface of the sensing film reacts and bonds to form a bonding layer on the surface. The potential is formed, and the sensitivity is calculated by using the change of the potential in different concentration solutions, and the sensing model is also called the Site Binding Model. At present, ion sensing field-effect transistors can be applied in a wide range of fields, such as food testing, industrial waste, medical medical testing, environment, agriculture, drinking water testing, etc., but the bottlenecks encountered in their development are mainly It is summarized into the following three points: 1. It is difficult to miniaturize the reference electrode, 2. The stability of the package, and 3. The non-ideal effect of the sensing film.

In terms of the difficulty of miniaturization of the reference electrode, a complete sensing system must contain many parts, in addition to the highly sensitive sensing components and good signal processing wiring, a stable and robust reference electrode (Reference) Electrode, RE) is quite necessary. Therefore, the miniaturization of the reference electrode has been the research that many scholars have been discussing, but it is also the most difficult problem in the sensor miniature technology.

For the currently developed sensing system, the most common reference electrode is a silver chloride electrode (Ag/AgCl), but this electrode has a short lifetime and is difficult to miniaturize and integrate the sensing element on the same wafer. Disadvantages.

In view of the above, the present invention provides an ion sensing device comprising at least a substrate, a first electrode, a second electrode, a sensing film, and a packaging material. The first electrode is disposed on the substrate and has a first body portion and a plurality of first finger portions electrically connected to the first body portion. The second electrode is also disposed on the substrate and has a second body portion and The plurality of second fingers are electrically connected to the second body, and the plurality of first fingers and the plurality of second fingers are parallel to each other and alternately arranged to form a sensing region. The sensing film covers the sensing region, and the encapsulating material is disposed on the periphery of the sensing region to encapsulate the sensing region.

In an embodiment of the invention, the substrate is a plastic substrate.

In an embodiment of the invention, the sensing film is a polymer material, and it may be polydioxylthiophene/poly-p-styrenesulfonic acid (PEDOT:PSS).

In an embodiment of the invention, the first electrode and the second electrode are both a conductive material, and the conductive material is selected from the group consisting of indium tin oxide, aluminum zinc oxide, gallium zinc oxide and indium zinc oxide. group.

In an embodiment of the present invention, the measuring method of the ion sensing device comprises at least the following steps: first, a solution to be tested and an ion sensing device are installed. The membrane reaction was sensed. Next, a resistance change amount between the first electrode and the second electrode is measured, and a pH value of the solution to be tested is obtained by the resistance change amount.

In an embodiment of the invention, wherein the ion sensing device is measurable with a pH value between pH 4 and pH 10.

Another object of the present invention is to provide a method for fabricating the above-described ion sensing device, comprising at least the following steps: First, a substrate is provided. And depositing a conductive film on the substrate, and patterning the conductive film to define a first electrode and a second electrode, wherein the first electrode has a first body portion and a plurality of first portions electrically connected to the first body portion a second electrode having a second body portion and a plurality of second finger portions electrically connected to the second body portion, and the plurality of first finger portions and the plurality of second finger portions are parallel and alternate with each other Arranged to form a sensing region. Then, a sensing film is formed to cover the sensing region, and finally the sensing region is encapsulated.

In an embodiment of the invention, the step of patterning the conductive film further comprises the steps of: first coating a photoresist layer on the conductive film, and performing a developing process on the photoresist layer through a photomask. Then, the photoresist layer not covered by the mask and the conductive film not shielded by the photoresist layer are sequentially removed. Finally, the photoresist layer is removed to complete the process of patterning the conductive film.

In an embodiment of the invention, the step of removing the conductive film not masked by the photoresist layer is performed by a wet etching process.

In an embodiment of the present invention, the ion sensing device measures a pH value of a solution to be tested by a resistance change amount between the first electrode and the second electrode, and the pH value is Between pH 4 and pH 10.

Therefore, the advantages and spirit of the present invention can be as follows A further understanding of the description of the figures is provided.

Please refer to FIG. 1. FIG. 1 is a diagram showing the explosion of components of an ion sensing device according to a preferred embodiment of the present invention. The present invention provides an ion sensing device 100, wherein the ion sensing device includes at least a substrate 10, a first electrode 21, a second electrode 22, and a sense of the bottleneck of the ion sensing device. The film 30 and a packaging material 40 are measured.

Therefore, as shown in Fig. 1, it is preferable that the first electrode 21 and the second electrode 22 are both finger-shaped electrodes. The first electrode 21 is disposed on the substrate 10 and has a first body portion 21a and a plurality of first finger portions 21b electrically connected to the first body portion 21a. In addition, the second electrode 22 is also disposed on the substrate 10 and has a second body portion 22a and a plurality of second finger portions 22b electrically connected to the second body portion 22a, and the plurality of first finger portions 21b and the The plurality of second fingers 22b are parallel and alternately arranged to form a sensing region S. In a preferred embodiment, the first electrode 21 and the second electrode 22 are each a conductive material, and the conductive material is selected from the group consisting of indium tin oxide, aluminum zinc oxide, gallium zinc oxide, and indium zinc oxide. group.

Next, as shown in FIG. 1 , the sensing film 30 covers the sensing region S, and the encapsulating material 40 is disposed on the periphery of the sensing region S to encapsulate the sensing region S. Wherein, the sensing film is a conductive polymer material, and preferably it is polydioxyethylthiophene/poly-p-styrenesulfonic acid (PEDOT:PSS). As the encapsulating material 40, an epoxy resin can be used, but the invention is not intended to be limited thereto.

In the preferred embodiment shown in Figure 1, the substrate 10 is a plastic substrate. That is, used in the ion sensing device 100 provided by the present invention. The substrate 10 is a soft board which has high flexibility, so that the front end of the clothes, straps, diapers, masks or surgical instruments can be easily combined to detect the change of the pH value of the human body fluid at any time.

According to the architecture of the ion sensing device 100 described above, the measurement method is further described as follows. First, a solution to be tested is reacted with the sensing film 30 of the ion sensing device 100. Basically, the above steps are not limited to directly inserting the ion sensing device 100 into the solution to be tested, or dropping the solution to be tested on the sensing film 30. Next, the amount of change in resistance between the first electrode 21 and the second electrode 22 is measured, and by this resistance change amount, the pH value of one of the solutions to be tested is known. It should be noted that the present invention infers the pH value by the amount of resistance change between the first electrode 21 and the second electrode 22, so that the ion sensing device 100 can discard the necessary use in the conventional ion sensing device. The reference electrode and the saturated solution are miniaturized, and the flexible substrate 10 can be used again to explain that the ion sensing device 100 of the present invention can easily incorporate the aforementioned clothes, straps, diapers, masks, or surgical instrument front ends.

Next, another object of the present invention is to provide a method for fabricating the above-described ion sensing device 100. Please refer to FIGS. 2A to 2G for the manufacturing method. FIGS. 2A to 2G are diagrams showing a preferred embodiment of the present invention. Flow chart of the method for manufacturing the ion sensing device.

First, as shown in FIG. 2A, a substrate 10 is provided, and the substrate 10 is preferably a plastic substrate. Next, a conductive film 20 is deposited on the substrate.

Then, as shown in FIG. 2B, a photoresist layer PR is coated on the conductive film 20. In the present invention, the photoresist layer PR may be a positive photoresist or a negative photoresist, the only purpose of which is to pattern the conductive film 20, so the present invention is not intended to be limited to any embodiment.

Next, referring to FIG. 2C, after performing a development process on the photoresist layer PR through a photomask (not shown), the photoresist layer PR not covered by the mask is removed.

Finally, as shown in FIG. 2D, the conductive film 20 not shielded by the photoresist layer PR and the photoresist layer PR are removed to complete the process of patterning the conductive film 20, thereby defining the original conductive film 20 as the first electrode. 21 and the second electrode 22. Preferably, the steps of removing the photoresist layer PR and the conductive film 20 are performed by an etching process, which is preferably a wet etching process, but the invention is not limited thereto.

In addition, the first electrode 21 has a first body portion 21a and a plurality of first finger portions 21b electrically connected to the first body portion 21a, and the second electrode 22 has a second body portion 22a and a second portion. The plurality of second fingers 22b are electrically connected to the body 22a, and the plurality of first fingers 21b and the plurality of second fingers 22b are parallel and alternately arranged to form a sensing area (not shown). As for the material selection of the first electrode 21 and the first body portion 21a and the first finger portion 21b, the second electrode 22, and the second body portion 22a and the second finger portion 22b thereof, as described above, it is no longer Narration.

Then, as shown in FIG. 2E, a sensing film 30 is formed to comprehensively cover the substrate 10 and the first electrode 21 and the second electrode 22 disposed on the substrate 10.

Subsequently, as shown in FIG. 2F, the sensing film 30 is patterned by using another photoresist layer and a photomask (not shown) so that the sensing film covers only the first finger portion 21b of the first electrode 21 and the first portion. The second finger 22b of the two electrodes 22 is formed on the sensing region. Preferably, the sensing film is a conductive polymer material, and it is preferably polydioxyethylthiophene/polybutylenesulfonic acid (PEDOT:PSS), but the invention is not limited thereto.

Finally, as shown in FIG. 2G, since the present invention is only intended to pass through the sensing region formed by the first finger portion 21b of the first electrode 21 and the second finger portion 22b of the second electrode 22 in the ion sensing device 100, The pH value of the liquid or human body fluid is measured, so that the sensing region 40 is further encapsulated by the encapsulating material 40 to isolate the sensing region from other regions. Preferably, the encapsulating material 40 is an epoxy resin and can be disposed on the periphery of the sensing region by dispensing.

Please refer to FIG. 3, which is a schematic diagram showing the relationship between the pH value of the solution to be tested and the resistance change amount of the ion sensing device when the ion sensing device according to a preferred embodiment of the present invention is used for measurement. The ion sensing device provided by the present invention measures the pH value of a solution to be tested by a resistance change amount between the first electrode and the second electrode. As shown in FIG. 3, the ion sensing device can be The different ion concentrations in the solution are measured. Taking hydrogen ions as an example, the energy value measured by the energy is between pH 4 and pH 10, and the range of human body fluid has been covered.

In summary, the present invention provides an ion sensing device and a manufacturing method thereof. Since the ion sensing device of the present invention uses the measurement of the resistance change amount to know the pH value of the solution to be tested, it is not required. The conventional Ag/AgCl reference electrode, which is bulky and easily broken, is pH-tested with a saturated solution of KCl, which can be easily miniaturized. In addition, since the substrate used in the present invention is a flexible substrate, the ion sensing device can be directly sewn into clothes, straps, diapers, masks, surgical instruments, or any highly permeable PP woven fabric to form a detachable. The sensing device senses different parts of the body, so that the control of the patient's condition can be monitored at any time, and the mobility and sensitivity of the home care system can be improved. Of course, the present invention is not limited to application to a home care system, and can be applied to a general industry as a general pH measurement device.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; all other equivalent changes or modifications which are not departing from the spirit of the present invention should be included in the following. Within the scope of the patent application.

100‧‧‧Ion sensing device

10‧‧‧Substrate

20‧‧‧Electrical film

21‧‧‧First electrode

21a‧‧‧First Body

21b‧‧‧ first finger

22‧‧‧second electrode

22a‧‧‧Second body

22b‧‧‧second finger

30‧‧‧Sensing film

40‧‧‧Packaging materials

PR‧‧‧ photoresist layer

S‧‧‧Sensing area

1 is a view showing an exploded view of an element of an ion sensing device according to a preferred embodiment of the present invention; and FIGS. 2A to 2G are views showing a flow chart of a method for fabricating an ion sensing device according to a preferred embodiment of the present invention; Fig. 3 is a view showing the relationship between the pH value of the solution to be tested and the resistance change amount of the ion sensing device when the ion sensing device according to a preferred embodiment of the present invention is used for measurement.

100‧‧‧Ion sensing device

10‧‧‧Substrate

21‧‧‧First electrode

21a‧‧‧First Body

21b‧‧‧ first finger

22‧‧‧second electrode

22a‧‧‧Second body

22b‧‧‧second finger

30‧‧‧Sensing film

40‧‧‧Packaging materials

S‧‧‧Sensing area

Claims (10)

An ion sensing device comprising: a plastic substrate; a first electrode disposed on the plastic substrate and having a first body portion and a plurality of first fingers electrically connected to the first body portion; The second electrode is disposed on the substrate and has a second body portion and a plurality of second fingers electrically connected to the second body portion, wherein the plurality of first fingers and the plurality of second fingers Parallel to each other and alternately to form a sensing region; a sensing film covering the sensing region, wherein the sensing film is a polymer material; and a packaging material disposed on a periphery of the sensing region. The ion sensing device of claim 1, wherein the polymer material comprises polydioxyethylthiophene/poly-p-styrenesulfonic acid (PEDOT:PSS). The ion sensing device of claim 1, wherein the first electrode and the second electrode are both a conductive material. The ion sensing device of claim 3, wherein the conductive material is selected from the group consisting of indium tin oxide, aluminum zinc oxide, gallium zinc oxide, and indium zinc oxide. The ion sensing device of claim 1, wherein the measuring method comprises at least the steps of: reacting a solution to be tested with the sensing film of the ion sensing device; and measuring the first electrode and One of the resistance changes between the second electrodes, And determining the pH value of the solution to be tested by the resistance change amount. The ion sensing device of claim 5, wherein the measurable pH value is between pH 4 and pH 10. A method for fabricating an ion sensing device includes at least the steps of: providing a plastic substrate; depositing a conductive film on the plastic substrate; patterning the conductive film to define a first electrode and a second electrode, wherein the first The electrode has a first body portion and a plurality of first finger portions electrically connected to the first body portion, and the second electrode has a second body portion and a plurality of first portions electrically connected to the second body portion a second finger portion, and the plurality of first finger portions and the plurality of second finger portions are parallel and alternately arranged to form a sensing region; forming a sensing film covering the sensing region, wherein the sensing film is a a polymeric material; and encapsulating the sensing region. The manufacturing method of claim 7, wherein the step of patterning the conductive film further comprises the steps of: coating a photoresist layer on the conductive film; and performing the photoresist layer through a photomask a developing process; removing the photoresist layer not covered by the mask; removing the conductive film not masked by the photoresist layer, by a wet etching process; and removing the photoresist layer. The manufacturing method of claim 7, wherein the first electrode and the second electrode are made of indium tin oxide, aluminum zinc oxide, gallium zinc oxide, and Selected in groups such as indium zinc oxide. The production method according to claim 7, wherein the polymer material comprises polydioxyethylthiophene/poly-p-styrenesulfonic acid (PEDOT:PSS).